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|11-14-2009, 12:25 AM||#1|
4.9L SC Stroker !!!
Car Audio and the Ford Focus
So here we go from start to finish on every topic. These are the top things I see and deal with in regards to car audio and the ford focus. I have spent hundreds and hundreds of hours working on "sound" inside my ZX4. I am going to share with you what I know about achieving different types of sound inside our vehicles and vehicles in general.This will include a brief history of things as well, some facts people tend to forget about car audio in general. It's important to remember where ya came from in this game.
I will be discussing the ZX4 and ZX3 in detail as I have little exp with the wagons, sorry guys, PM your info and we can include it if it's missing.
Topics covered but not limited to are:
-common terms for car audio
-common equipment for car audio
-common installation techniques for car audio
-common trouble shooting in car audio
then pertaining specifically to OUR cars;
-transient response of the interior of a 2005 Ford Focus
-noise floor and noise floor issues with the Ford focus
-common issues with audio systems and the Ford Focus
-trouble shooting specific issues related to car audio and the Ford Focus
-Why our cars sound the way they do inside
Today I decided to start with some general history to take us into things. Sit back and be ready to learn.
Moderators, I am doing this in parts, maybe at the end or as the topics finish maybe you could help me organize a little better.
History of Car Audio
Source Unit History-
In the 1920's an inventor named William Lear was playing with the idea of building a device that would receive a radio transmission in a moving vehicle. Lear did design the first car radio but didn't have the money to produce it. That happened in 1929 when Paul Galvin and Lear joined forces, and then in 1930 after buying the rights from Lear, Galvin produces the first car radio receiver as an aftermarket add-on. It was called a motorized-victrolla or "motorolla". It took two or three men several days to install it and cost around $150. Galvin Manufacturing became what we know today as Motorolla.With popularity increasing, car manufacturers started offering the radios as an option in 1936. In the early 1960's the 8-track came to be. Its design again coming from William Lear, now the owner of LearJet, the same man that designed the first car radio. The eight track was special because it could play four stereo programs running in parallel on eight tracks for the the length of a single continuous tape loop.
Now here's where it gets personal to us. In 1966 Lear signed a contract with Ford Motor Company, the first manufacturer to offer an in-dash radio-eight track player as a factory option. This format gave Ford the edge in car audio and a boost in sales.
Next came the tape cassette in the mid to late 70's and that dominated the market until... the CD player was born!
In 1984 Pioneer Electronics introduced the first car audio CD player. Then in 1987 Pioneer introduced its "multi-play" magazine format aka the CD changer. Another first for the industry from Pioneer, the first DVD based car navigation system!
First MP3 format CD player was made by Rockford Fosgate in 2000.
First in car DVD audio-format player was from Panasonic in 2001, the advantage being the amount of data you could store on a disc increased so the music quality also went up. There was no need to compress your music and damage its sound quality.
And most recently Pioneer introduced the newest tech advantage in Head Units with the internal Hard Drive system. Load a disc once and have it as long as you own the head unit.
Now let's talk a little about...
History of car audio speakers
The first patent for any type of speaker design is held by Ernst W. Siemens, a German Patent for a non-magnetic parchment diaphragm as the sound radiator of a moving coil transducer. Pheeewww!! Also known in regular peoples terms as a paper cone attached to a voice coil. This was the standard of speakers used until the 1920 when along came Edward Pridham and Peter Jensen to introduce the first production dynamic loudspeaker. The frequency response of this speaker was from 325 Hz to 3000 Hz and they named it the "Magna-Vox" which is Latin for "great voice". Soon after that Magnavox Corporation was started. In 1925 Peter Jensen left Magnavox and created Jensen Radio Manufacturing in 1927.
1924 Jensen introduced the first commercially available 2 way coaxial loudspeaker.
In 1936 Jensen released the first bass reflex enclosed speaker system and in...
In 1952 Jensen released the first horn-type super tweeter and again in
1960 Jensen released the first flat-piston style woofer.
Peter Jensen was the driving force behind what we today call the world of car audio.
Car Amplifier History
Amplifiers are a HUGE part of the car audio industry, from small amplifiers that are built into the head units in our dash's, to the large amplifiers making 1000 watts or more to power huge sub-woofer systems, they are EVERYWHERE! From stock OEM systems to competition systems, there are amps! The name says it all, its main purpose is to amplify.
In 1957 Cerwin Vega introduced the first solid state amplifier for use in car audio systems. It made 125 watts RMS and when it was released it crushed the competitors.
That is until Jim Fosgate, the founder of the legendary Rockford Fosgate introduced the first MOSFET based amplifier design in 1976. It could handle lower impedance levels as well as having the ability to run in stereo and mono modes simultaneously. The basic design of the amplifier didn't change until the 1990 when class D amplifiers were produced. They produced much more power than the other amplifiers and they did it more efficiently.
Hopefully now there can be some common understanding of how car audio started and progressed to roughly where we are now.
Another very important part of this history is owed to the credit of Albert Neville Thiele and Dick Small. Both were pioneers in speaker testing, however, Thiele's work was not recognized until the late 1960's when Small's work which was guided by Thiele's work was released. Without the research of these two men would would still be in the dark ages in regards to speaker performance and applications.
That leads me to the next quick topic, quality sound.
I.A.S.C.A. is an acronym for the International Auto Sound Challenge Association.
but what or who is IASCA?
IASCA is a Car Audio community made up of Auto Sound and Car Show Enthusiasts, Soundoff Competitors and Industry Members that include Car Audio Dealers and their Customers, Distributors, Manufacturers and their Representatives. I am including a link to their site because trying to explain it all here would take days. Just know that if you are looking for the pinnacle of car audio, you can find it here.
Far more often than not, the term "sound quality" gets mentioned directly before or after the terms, "expensive" or "big system", please be aware this is not always the case, usually its not.
According to the pinnacle, IASCA, " SQC (Sound Quality Challenge) scoring is based on the IASCA judging criteria of; Tonal Accuracy, Sound Stage, Imaging, Sound Linearity, and Absence of Noise." so let's look at these individually.
Tonal Accuracy- Tonal accuracy is just that,how accurately can your system duplicate the sound of the original recording.
Sound stage- Sound stage is the ability to visualize the placement of musical instruments and vocalists in a music recording. A good sound stage also allows the listener to perceive the size and space of the performance venue in which the recording was made.
Imaging- Imaging is the ability to visualize the spatial location of various instruments and vocals in a music recording.
Sound Linearity- how evenly music is reproduced throughout the frequency bandwidth. Flat-sounding systems that do not emphasize or de-emphasize one frequency segment over another.
Abscence of noise- Noise refers to anything that does not exist in the original program material, and is created by the vehicle's electronics or the audio system.
So, if you were looking to have a "Pro" system with out having all the sponsors to pay for your equipment you need to do research on how your car interior responds to specific frequencies. Also how it measures up to the criteria above.
Tonal Accuracy starts at the head unit and ends at the listener's ears. Everything in between contributes to it in one way or another. If your Head Unit (referred to as HU from here out) has a high level of distortion upon playback of the media source (cd, mp3, etc) then its only natural that everything in sequence after it will produce the same amount of distortion if not more. It tends to snowball as the signal (music) travels from one piece of equipment to the next unless its "processed" by either an Equalizer or some type of cross-over whether it be before or after the amplifier. Later we will discuss which type of processor goes where in regards to which equipment.
Now on to imaging. Stereo imaging is defined as the illusion of lateral and vertical placement of instruments across a stage. Systems that have a spatial quality in which the sound seems to float in mid-air are said to have good "staging" . Far to often people tend to sacrifice staging and tonal accuracy for higher SPL (Sound Pressure Levels) by adjusting their HU's EQ to emphasize mid and low frequencies because their speakers are not producing those tones accurately according to the ear.
Regarding equalization settings. In most cases, setting your equalizer for maximum smoothness will not result in maximum SPL. Conversely, adjusting your equalizer for maximum SPL will definitely not result in a smooth frequency response. ALWAYS adjust your equalizer for maximum smoothness. This will only affect your SPL slightly. Proper tuning would suggest you lower the frequencies your speakers have no problem recreating, rather than boosting those the speakers are having problems with already causing distortion to occur. So rather than raise the level of your mid's, try dropping the levels of your high's and low's first.
Now here is where years of experience pays dividends to you. This is a chart showing the difference between good frequency response inside the car and bad frequency response inside the car.
Notice that little plateau around the 220 Hz to 320 Hz range? Its because that where the resonant tone of the car took over and increased the SPL across the portion of the frequency range. If all you want to be is loud, higher SPL is created by a higher note.
Figure 3 shows an even response through out the entire audible range. Other wise known as "good sound" in regards to frequency accuracy. Does this mean the vehicle has good sound?
No it does not.
Now we get to the absence of noise. And this is where product and installer have to become one. The installer must drive the car to determine its current acoustic characteristics.
Determine the floor noise level, which pertains to the amount of noise the car makes itself, whether that be from driving and hearing the tires or being parked and hearing "engine-noise", maybe the gains on the amp are set to high creating to much signal? Eliminating the "noise" is 90% installation and 10% product. Even the best products installed incorrectly will not function properly.
Installation of the equipment is going to account for around 75% of total "good sound".
And installation is where I will pick this up tomorrow.
Stay tuned as this thread will cover 20 years of car audio experience and the last four years of it being devoted to the Ford Focus.
MECP 1ST CLASS
FF08 FASTEST OVERALL TRACK TIME
|11-14-2009, 02:17 AM||#2|
4.9L SC Stroker !!!
Glossary of Car Audio Terms
Glossary of common car audio terms.
Acoustics-Sound is simply vibrating air. How fast, how much, and when the air is vibrated, determines what we will ultimately hear as sound. The science of this process is called acoustics.When a speaker cone (or anything else that has the ability to vibrate in the auditory range) moves forward, the air molecules in front of the cone are compressed, causing the molecules to form an accelerating wave forward. This continues to happen until the speaker cone moves in the opposite direction, which causes a rarefaction (or thinning) of the air mass between the speaker and the listener. This is the basic concept of how sound waves are produced.
Amplifier-A device, either a single stage or a large scale circuit with mutiple stages for creating gain, ie. making small signals larger.
All sound is a sinosoidial waveform. It has alternating peaks and valleys. The center point of each wave is the zero, or switching point that separates the positive (top) from the negative (bottom) portion of each wave. When a tube or transistor amplifier operates in Class A, the output tubes or transistors amplify the entire waveform without splitting it into positive and negative halves. In Class AB, used in the overwhelming majority of amplifier designs, the signal is split into two halves, positive and negative, and each half is sent to a tube or transistor circuit for amplification. Both sides work in tandem, and the two halves are recombined at the output section to reconstruct the whole signal. This technique increases the amount of power that can be applied, but increases distortion. Class A amps usually provide lower, often imperceptable distortion, but at the expense of reduced power output.Class D or High Current operation is essentially rapid switching, hence the term switching power amplifier. Here the output devices are rapidly switched on and off at least twice for each cycle. Theoretically, since the output devices are either completely on or completely off they do not dissipate any power. If a device is on there is a large amount of current flowing through it, but all the voltage is across the load, so the power dissipated by the device is zero; and when the device is off, the voltage is large, but the current is zero. Consequently, class D operation (often, but not necessarrily digital) is theoretically 100% efficient, but this requires zero on-impedance switches with infinitely fast switching times -- a product yet to be made; meanwhile designs do exist with efficiencies approaching 90%. This is a design that is increasimgly popular for use in bass systems, where maximum power is necessary, and slightly elevated levels of distortion are easily tolerated.
Baffle- A flat panel that divides the front and rear sound waves produced by a woofer. Sometimes baffle is used to mean an enclosure or the front panel on which the speaker is mounted .
Acoustic Coupling-The interaction between two or more speakers stacked together in an audio system which may produce a sound different from (and often better than) the sound produced by the individual speakers.
Sealed-Acoustic Suspension-A Sealed box system that uses the resistance of the internal air of a sealed enclosure to control the motion of the cone. Sometimes known as an infinite baffle type.
Bandpass (box or enclosure)- An enclosure that is specifically tuned to give maximum energy to a very limited range of frequencies, usually the lowest. In this arrangement, the woofers are fully enclosed in the box with the sound pressure being vented through one or more ports.
Aperiodic- Refers to a type of bass-cabinet loading. An aperiodic enclosure type usually features a very restrictive, (damped), port. The purpose of this restrictive port is not to extend bass response, but to yeild a smoother response pattern by lowering the Q of the system and reducing the impedance peak at resonance. Most restrictive ports are damped with quantities of sound absorbtive material.
Alternating Current-Electricity which flows in opposite directions, alternating at a certain rate (Hz). As supplied by power companies, AC in the United States alternates 60 times per second and is deemed as 60 Hz power.
Alternator Whine-A siren-like whining that appears as the rotational speed of an engine increases. The noise is usually the result of a voltage differential created by more than one ground path or a poor ground path to the affected equipment.
Amperes (A)-Ampere is a unit measurement of current of electrical energy equal to one coulomb of charge per second. Most DC applications refer to positive current - current which flows from a positive potential to a more negative potential, with respect to a reference point which is designated as zero or neutral potential (usually ground).
The electrons in a circuit flow in the opposite direction as the current itself. Ampere is commonly abbreviated as "amp", not to be confused with amplifiers, of course, which are also commonly abbreviated "amp". In math, the abbreviation for amperes is commonly, "I".
Attenuate- The act of reducing the Amplitude or intensity of a signal. In speaker systems, high frequency drivers are commonly more efficient than low frequency drivers. This creates a need to adjust the driver levels to create a uniform overall frequency response.
AWG- Acronym for American Wire Gauge, a standard for measuring the diameter of wire commonly used in electrical circuits. The higher the AWG number, the smaller the thickness of the conductor. For power carrying, choose lower numbers; for signal only wires, choose a higher number.
Bandpass filter- A filter that has a finite passband, neither of the cutoff frequencies being zero or infinite. The bandpass frequencies are normally associated with frequencies that define the half power points, i.e. the -3 dB points. In multi-driver speaker systems, the Midrange driver may be fed by a bandpass filter.
Bandwidth- Abbr. BW- The numerical difference between the upper and lower -3 dB points of a band of audio frequencies. Used to figure the Q, or quality factor, for a filter.
Basket- The metal frame structure of a standard dynamic loudspeaker. In larger, heavier speakers, this may be made of cast metal for extra strength and rigidity. All the other elements of the speaker are mounted on this structure.
Bass- The portion of the audible sound spectrum that contains the lowest frequencies. These frequencies have the longest wavelength and require considerably greater electrical power to render them at their original strength. In a good modern speaker system, the bass portion of the response curve extends from as high as 500 hertz, down to 20 Hz.
Bass Boost/Enhancer Circuit- An active low pass amplifier section added to some receivers, equalizers, and amplifiers that allows as much as an 18 decibel boost to be applied to an audio signal in the low frequency 35 to 90 Hertz range.
Bass Reflex (box or enclosure)- A speaker box design that makes use of a port or Passive Radiator which allows the energy derived from the motion of the back of speaker cone to be redirected in such a way as to reinforce the front radiation. This smooths and extends the low frequency response, but the effect is sharply Rolled Off on the low end, as the port signal goes back out of phase with the front. The overall effect of this is to tune the bass response to a particular point on the lower end of the spectrum, below which it rolls off sharply.
Bi-Amplification- Some speaker systems with multiple drivers do not contain a crossover network, and they require a separate amplifier for each frequency range. The bi-amplified system still requires an active crossover network to send the proper frequency band to each amplifier and speaker, but it is in the circuit preceding the amplifier and speaker and does not handle the power output
BBE 1 & 2 Processing- A signal processing circuit that provides improvements in imaging and spatial realism by altering the frequency and phase characteristics of portions of the input signal.
Boomy- Usually refers to excessivly reverberant bass response, or a peak in the bass response of a recording, playback, or sound reinforcement system.
Bridged Power- Bridging an amplifier, combines the power output of two channels into one channel. Bridging allows the amplifier to drive one speaker with more power than the amp could produce for two speakers. Because of this high power output, bridging is the best way to drive a single subwoofer.
If the amp is bridgeable, the owner's manual will have directions that tell you how. Usually, an amp is bridged by connecting the speaker leads to the positive (+) terminal from one channel and the negative (-) terminal from the other channel. However, be sure to consult your owner's manual before attempting to bridge your amp!
Also, keep in mind that most amplifiers need to see a 4-ohm load when bridged to mono operation. When bridging an amplifier, use one 4-ohm speaker or, if you prefer multiple woofers, connect two 8-ohm speakers in parallel. Again, consult your manual before operating your amp in bridged mode.
Built-in Crossovers- Frequently used to limit the high-frequencies reaching a subwoofer, a low-pass filter crossover allows only frequencies below the crossover point to be amplified. A high-pass crossover allows only frequencies above the crossover point to be amplified ó used to keep destructive low bass away from small speakers, so they can played safely. Crossovers may be variable or selectable. Continuously Variable means the crossover circuit can be adjusted to any frequency between the listed end points. Selectable means that any of several preset crossover points can be chosen to accomodate variuous driver (speaker) designs.
Cabin Gain- A low frequency boost normally obtained inside a vehicle interior when woofers are optimally in phase, and with the proper enclosures.
Capacitor (Power audio)- Power stabilizing capacitors store the necessary power amplifiers need to punch larger bass notes while limiting clipping. They store energy during intervals when it is not required, which is most of the time, and release it when demand exceeds what is available from the car's power system. The amount of capacitance to be used is half (.5) farad per 500 watts of available RMS power.
Circuit Breaker- An electrical switch that automatically breaks a circuit if the current through it is higher than its rating. Once tripped it can be manually reset. Performs the same function as a fuse, but eliminates the need for replacement after activating.
Channel- Common name for a complete amplifying stage in any audio amplifier. Most amplifiers are denominated as 1, 2, 4, 5, or 6 channel units. Each of these is a discrete audio amp on its own, capable of taking a small line signal input and amplifying it sufficiently to be heard on an appropriate speaker. Some amplifiers are capable of bridging two channels together, to form one channel of double the power of each separately. The manufacturer's instructions differ widely on how to accomplish this, and each must be followed exactly.
Clipping- A signal that results from an amplifier that is either overloaded or underpowered relative to the signal Amplitude it being asked to generate. A clipped waveform is one in which the gently rounded peaks and valleys of the AC audio wave are instead sliced off or clipped, to yield what looks a lot like a square or alternating DC wave. When DC is applied to a speaker, the voice coil has no means of propelling itself relative to a constant magnetic field. Instead, it can only convert the incoming current to heat, and ultimately burns up. The effect of alternating DC on speakers is remarkable, irritating, painful, and short. If you are able to hear evident Distortion at high volume levels, or smell smoke, reduce the volume. It may already be too late for your speakers, but at least you may be able to save the amplifier.
Component System- This term is used in relation to speaker systems, to indicate a system in which separate mounting arrangements are provided for each component of the system. In a typical car system you might see a woofer in a box in the rear, midranges at the side and tweeters mounted on the dash panel. This compares to the typical integrated speaker enclosure in which all the Drivers are mounted in the same box.
Cone- The cone-shaped diaphragm of a speaker. This is directly attached to the voice coil motor which actions produces the pulsation's of air that the ear detects as sound. Also useful for holding ice cream.
Crossover- A device or passive circuit used in systems with separate tweeter and/or midrange Drivers. It Rolls Off frequencies above and below certain points in the range, to allow the sound to be tailored for the specific driver to which it is sent. Most speakers have crossovers that consist of passive elements such as capacitors, coils, and resistors to separate the various frequencies. In a bi-amped or multi-amped system, the crossover is an active device that feeds the various frequency bands to the inputs of the amplifiers that operate the individual drivers.
Crossover Frequencies- The frequencies at which a passive or electronic crossover network divides the audio signals, which are then routed to the appropriate amplifiers or speakers.
Crossover Network- A unit which divides the audio spectrum into two or more frequency bands (Also see Crossover Frequencies).
Crossover Slope- The rate at which a crossover circuit attenuates the blocked frequencies. Slope is expressed as decibels per octave. A 6dB per octave crossover reduces signal amplitude level by 6dB in every octave starting at the crossover point. This means that every time the frequency of the audio signal is changed by a factor of 2 (one octave), the level of the audio signal is attenuated by 6dB. For example, if a low-pass crossover is set at 60Hz with a 6dB slope, you'll see a drop in level of 6dB at 120Hz. With slopes of 12dB and higher, the output beyond the crossover point will be reduced to below the level of audibility.
Cycles per second- See Hertz
As Newton observed, an object once set in ,motion will keep on moving unless a restrictive counterforce is applied. Damping is that force at work in the mechanical resistance that is applied to a speaker cone to keep it from resonating in the absence of an input signal. It is also the factor that is applied as a control voltage by the amplifier for the same purpose. These measures help reduce or dampen Harmonic Distortion. This also improves bass accuracy.
Decibel or dB (see also Efficiency and Sensitivity)
One tenth of a Bel. This is a measurement of the comparative strength of two powers, and can be applied when measuring any signal in the audio, video, and electromagnetic spectrum. If two powers differ by one Bel, there is a difference of 10 times the power. If comparing amplifiers, where one is rated at 10 watts while the other is 100 watts, then we have a difference of 10 decibels, or one Bel. Decibels should be understood as ratios, not fixed quantities.
Destructive Interference ( phase cancellation)
A phenomenon that occurs when speakers are 180 degrees out of phase, i.e., what one speaker is trying to produce, the other speaker is fighting to cancel. One speaker's wave is in the positive phase (rarefaction), while the other speaker's wave is in the negative phase (compression).
Acronym for Deutsche Industrie Norm (Deutsches Institut fuer Normung), the German standardization body. A world reference standard for the mounting parameters of many common receivers ( Head ends) as well as other types of cables and equipment. Single DIN is the standard face size for receivers, and measures 7-3/8"wide by 2-1/4" high. DIN+1/2 measures 7-3/8"wide by 3-3/8"high. Double DIN measures 7-3/8"wide by 4-1/2" high.
Any departure from a true and accurate reproduction of the original waveform. It can include Noise, Clipping Distortion, Harmonic, and Intermodulation Distortion. These last two forms are fairly common in loudspeaker reproduction and can be reduced but not entirely eliminated in the existing technology. It would be fair to say that modern amplifier design fairly eliminates nearly all forms of inherent perceived distortion, leaving only that caused by inappropriate user settings and overloading.
Distortion is the name given to anything that alters a pure input signal in any way other than changing its size. The most common forms of distortion are unwanted components or artifacts added to the original signal, including random and hum-related noise. Distortion measures a system's linearity - or nonlinearity. Anything unwanted added to the input signal changes its shape (skews, flattens, spikes, alters symmetry or asymmetry). A spectral analysis of the output shows these unwanted components. If a circuit is perfect, it does not add distortion of any kind. The spectrum of the output shows only the original signal - nothing else - no added components, no added noise - nothing but the original signal.
An alternate term for: speaker, transducer, or radiator. Properly speaking, the term speaker should refer to an entire sound producing system with whatever combination of woofer, midrange and tweeter; in whatever enclosure type it is housed.
Many factory installed auto speakers are of the dual cone type. Sometimes also referred to as a "full-range" speaker, it uses an inexpensive, efficient design. The small "whizzer" cone in the center of the woofer reproduces high frequencies, but not with the dispersion, range, or intensity of a separate tweeter.
Dual Channel or Dual Voice Coil (speaker)
A woofer with two voice coils mounted to a common cone, which can be connected to separate amplifiers, to produce a common bass output. Since bass has a non-directional character, this still permits the optimum reproduction of the stereo image via other speakers. Care should be taken in making connection, to observe proper polarities, however. Failure to do so can result in the quick extinction of the Driver if the amplifiers are pulling the cone in different directions at once.
The ratio of the loudest (undistorted) signal to that of the quietest (discernible) signal in a unit or system as expressed in decibels (dB). Dynamic range is another way of stating the maximum S/N ratio. With reference to signal processing equipment, the maximum output signal is restricted by the size of the power supplies, i.e., it cannot swing more voltage than is available. While the minimum output signal is determined by the noise floor of the unit, i.e., it cannot put out a discernible signal smaller than the noise. Professional-grade analog signal processing equipment can output maximum levels of +26 dBu, with the best noise floors being down around -94 dBu. This gives a maximum dynamic range of 120 dB - pretty impressive numbers, which coincide nicely with the 120 dB dynamic range of normal human hearing (from just audible to uncomfortably loud).
Efficiency Bandwidth Product. A parameter that helps determine the suitability of a driver for a sealed or ported enclosure. An EBP of less than 50 indicates the driver should be used in a sealed box, 50 - 90 indicates flexible design options including bass reflex, over 90 indicates the need for a ported enclosure. EBP = Fs / Qes
Electrolytic Capacitor or "CAP"
A polarized capacitor with a negative and a positive terminal that is commonly used for DC power filtration and energy storage. As with all capacitors, the dielectic insulator separates two plates and holds a charge. In this case the dielectric is a form of chemical electrolyte that is polarized. Smaller types are mesured in microfarads while the large ones used for amplifier stabilization are measured in farads. Values in the range of .5 to 3 farads are typical for use with car audio amplifiers.
A class of electronic filter circuits designed to augment or adjust electronic or acoustic systems. Equalizers can be fixed or adjustable, active or passive. Most consumer audio equallizers divide the spectrum into 3 to 12 bands, allowing each section to be either increased or decreased in amplitude without changing the response of the rest.
The back-and-forth travel of a cone in a dynamic Driver. How loud a speaker can play depends on how much air it can move without overheating. How much air can be moved is determined by the surface area of the cone as it moves back and forth (Xmax), the Enclosure resonance, and the suspension compliance of the motor system.
The basic unit of capacitance. A capacitor has a capacitance of 1F when a charge of 1 Volt across the capacitor produces a current of 1 Ampere through it. Named after Michael Faraday
The tuned frequency of a Vented Enclosure, measured in Hertz. A combination of the resonance frequency of the air in a Port and the resilient pressure of the air in a Ported System. Below this point the Frequency Response of a Tuned Port system rapidly Falls Off, and the system can become unstable if asked to reproduce lower frequencies at high volumes.
The range of frequencies that a speaker will reproduce (lowest frequency to the highest). While the optimal normal is 20 - 20,000 Hz (Hertz), the range of human hearing for individuals is often much more restricted. A good full-range speaker system however, will reproduce as much of this range as possible in order to cover all variations. Individual Drivers are limited to reproducing only that part of the spectrum for which they were made, so their response will be limited, but still a necessary point to consider when designing a complete sound system.
F3 (measured in Hz)
The frequency at which the acoustic power output from a system has fallen to one-half its reference value. Known as the systems 3dB down point. F3: determined by the frequency at which the output is 3dB lower than the level at 100Hz. This frequency was chosen because it is a typical crossover point. In the case of a Bandpass system, F3 is determined by the frequency at which the output is 3dB lower than the level at the middle of the pass band.
A multi-band variable equalizer using slide controls as the amplitude adjustable elements. Named for the positions of the sliders "graphically" illustrating the resulting frequency response of the equalizer. Only found on active (amplified)designs. Center frequency and bandwidth are fixed for each band.
A term that describes anything having an electrical potential of zero relative to other points in a circuit. Most modern vehicles are designed around a negative ground system, with the metal frame being the vehicle's ground.
The term given to the condition that occurs when a voltage potential exists between two separate ground points.
A type of Distortion in which resonance or sympathetic ringing vibrations are added to the original sound to produce second and third harmonics of a fundamental tone in a way that was not present in the original signal. Choosing good Drivers and a well-made enclosure design is essential in overcoming this tendency in speakers.
A term related to the dynamic range of amplifiers, used to express in dB, the level between the typical operating level and the maximum output level (onset of clipping). For example, a nominal +5 dBu system that clips at +25 dBu has 20 dB of headroom. Because the term depicts a pure ratio, there are no units or reference-level associated with headroom, only relative "dB." Therefore headroom expressed in dB accurately refers to both voltage and power. Which means the example above has both 20 dB of voltage headroom, and 20 dB of power headroom.
The measurement of frequency. One hertz is equal to one cycle per second, or the complete cycle of an alternating (AC) waveform. Higher frequencies are measured in kilohertz, (thousands of cycles per second) Megahertz, (millions of cycles per second), etc.
High Pass Filter
An electronic filter of a type commonly incorporated in Crossover circuits that permits the passage of high frequencies while suppressing lower ones. The place in the frequency spectrum where this occurs is called the crossover point and is different for each set of Drivers being considered. The most basic form of such filter is a non-polarized capacitor. Typical values for such a unit would be in the range of 1 to 100 microfarads.
Imaging describes the extent to which an audio system reproduces the directional cues that enable the listener to locate the instruments and vocalists as they were positioned during recording and mixing (See also Soundstage below). Good imaging creates a listening experience that seems natural and lifelike. Since directional cues in sound come mainly in the higher frequencies, the key to attaining the best possible imaging is to have equal and unobstructed path lengths between the tweeters and the listener's ears. That's one of the reasons why matched component speakers, with their versatile tweeter placement, sound as good as they do.
Radiated noise that is transmitted through a magnetic field to surrounding lines. This frequently occurs in long runs owire where power and signal cables are in too close proximity. This is a frequent source of noise and interference.
Waves or vibrations with frequencies below that of audible sound (20 Hz.).
Input Overload Distortion
Distortion caused by too great an input signal being sent to an amplifier or preamplifier. It is not affected by volume control settings and often occurs when mics are positioned too close to the sound source. This distortion may be controllable through the use of an attenuator or pad.
Sometimes spelled Isobaric, this is an enclosure design in which two or more Drivers are coupled together by a sealed air mass to operate as a single driver. With proper sealing and design, very impressive results can be obtained from an unusually small box. A popular version of this simply consists of two woofers placed over each other in a 'clamshell' design. The downside consists of the fact that it does require at least twice the amplifier power as would be needed for a conventional speaker, in order to be operated successfully.
Refers to a receiver mounting system in which the headunit is mounted behind the dash panel with side brackets, employing factory installed trim panels.
Low Pass Filter
A network of components which attenuate all frequencies above a predetermined frequency selected by the designer. Frequencies below cut-off are passed without any effect.
A low Q, or QTS, (reactance) woofer Driver is desirable for use in a vented enclosure.
Those frequencies roughly between 100 and 300 Hertz.
A common term used to describe a VOM. A multimeter usually has the ability to measure volts, ohms, and amperes or milliamperes.
Normally the lowest threshold of useful signal level (although sometimes audible signals below the noise floor may be recovered).
The measurement of electrical resistance and system impedance. It is a measure of the degree to which electrons are limited in both velocity and quantity in passing through a circuit.
A circuit in which two or more devices are connected to the same source of voltage, sharing a common positive and negative point, so that each device receives the full applied voltage.
A multi-band equalizer enabeling control of at least three essential "parameters" of the internal bandpass filter sections. These parameters being: amplitude, center frequency and bandwidth. This allows the user to not only control the amplitude of each band, but also to shift the center frequency and to widen or narrow the width or coverage of the affected section of the aural spectrum.
Sometimes known as a "drone cone," these passive devices respond to internal pressure within the speaker and react to it to produce reinforcing emissions to extend the output of the lower frequencies below the resonance point of the active woofer. They may look like Drivers but they lack an active motor assembly.
In a crossover system, a non-powered component used to separate an audio signal into a specified frequency band before it goes to a particular amplifier or driver. A passive device usually incurs some loss (expressed in decibels) to a system. Typical such components include capacitors, coils, and resistors.
Peak Power Handling (MAX)
Peak power handling refers to the amount of power a speaker is estimated to handle during a brief high-intensity musical burst. Since this can vary with both frequency and amplitude, it is a much less accurate way to judge speaker durability and performance than RMS (see RMS).
A phase-shifted sine wave appears displaced in time from the input waveform. This displacement is called phase delay.
Any audio system which accurately preserves phase relationships between frequencies, i.e., that exhibits pure delay.
The fraction of a complete cycle elapsed as measured from a specified reference point and expressed as an angle. 2. Out of phase in an un-synchronized or un-correlated way.
An opening, usually a tube, in an enclosure, through which sound is permitted to pass.
The measurement across the port opening. Measured as internal diameter (not outer diameter .
The measurement of the length of the port tube.
Any enclosure design with ports. In such designs the internal pressure wave is processed to be used either solely, or in conjunction with the woofer front wave in order to produce sound. A port can be a simple opening, a tube or a Passive Radiator.
Power Handling (continuous or RMS)
A rating of a Driver's ability in optimum conditions to handle a specified amount of audio power (electrical current power) on a constant basis, without damage. This is generally considered to be a conservative and reliable figure to use in judging what types of amplifier power will be most successful with a particular speaker design.
A circuit unit which takes a small signal and amplifies it sufficiently to be fed into the power amplifier for further amplification. A pre-amp includes all of the controls for regulating tone, volume, and channel balance.2
Typically found on headunits, a preamp output provides low level, high quality audio signal for use with external amplifiers.
Also known as the Haas effect, this phenomenon identifies the tendency for the ear to attribute all perceived sound to the nearest emitter, even if a more distant speaker is actually louder. Thus, drums that yield 90 percent or more of their energy in the non-directional lower frequencies are perceived as located in the space created by the tiny amount of higher frequency overtones. It is also for this reason that sounds from the rear speakers of a surround system are delayed by 10 to 30 milliseconds, so that they can be experienced as coming from the rear direction.
The ratio of reactance to resistance in a series circuit, or the ratio of resistance to reactance in a parallel circuit.
The Q of a speaker driver at its free air resonance considering only its electrical losses.
The Q of a speaker driver at its free air resonance considering only its mechanical losses
The total Q or resistance of a woofer and sealed enclosure at the systemís resonance frequency, considering all resistive losses. A Qtc of .7 has smoothest response and the lowest resonant frequency response. A Qtc of above 1.1 should only be used by those who prefer a "boomy" response.
The total resistance in a series or parallel circuit. This takes into account all Driver resistances, both electrical and mechanical.
Usually described as frequency range, this is a system's frequency transmission limits, beyond which the frequency is attenuated below a specified tolerance. Also, the frequency band or bands within which a receiver or component is designed to operate.
In sound waves, the opposite of compression. An area of decreased air pressure caused by a sound wave. In a graphical depiction of a cyclical waveform rarefaction occurs when the wave is in the bottom segment. Sound is simply the alternating compression and rarefaction of air at varying and often overlapping frequencies, within a range to which humans are sensitive.
Rem or Remote wire
The cable connected between the amplifier and the receiver that turns on the amplifier whenever the receiver is on. The receiver's connection supplies a 12 volt signal only, that may be used simultaneously to turn on such devices as an equalizer, amplifier, and to raise the antenna.
The tendency for a mechanical or electrical systems to vibrate or resonate sympathetically at a certain frequency when stimulated by external energy. Every element and material has a particular natural resonance point. The job of the speaker designer is to minimize these output peaks whenever they appear so that a smooth response is created.
The frequency at which a speaker cone vibrates with the least inertia. The point on the spectrum at which it has the greatest amplitude relative to all other applied frequencies.
Abbreviation for reverberation, a complex blend of multiple interacting reflections within an enclosed space which combines with the direct sound from a source and defines the character of the sound in a room or hall. It is also used for a signal processor which can generate an approximation of natural reverb. (Caution: do not confuse with 'Echo' - a different effect altogether.)
The sound field that exists when the reflected sound at a listening position predominates over the direct sound from the source. This contrasts with near field effects. Layout, reflectivity and spatial parameters will strongly influence the creation of this situation.
A device that converts a signal (typically audio and/or video) into a radio frequency. This can be received by a tuner and converted to perceptible information.
A train of pulses that occurs when AC is changed to DC via a rectifier. These pulses are left on the DC if not filtered and regulated properly, or if toomuch current is being drawn.
The maximum deviation from flat response, measured in decibels-it indicates the port's effect on woofer output.
Root Mean Square is a formula that provides a reasonably accurate means of measuring and comparing continuous AC power. The use of this measure is preferred when matching system components, like amplifiers and recievers. (see Power Handling)
A graduated reduction in the strength of audio output above and below certain specified frequencies. (See Crossover)
The effectiveness of any speaker system is a function of the room or environment in which it is played. The coupling of the speaker to the room or listening space is a function that is as critical as that between the woofer and the enclosure. When in doubt, experiment! This is the only practical method of achieving the optimal response form speakers in nearly any situation. Of course, computer modeling based on real time measurements could be substituted, albeit quite expensively.
Sd (a Theile Small parameter)
Effective piston radiating area of a subwoofer driver in square meters.
The frequency attenuation that occurs at a rate of 12 dB per octave.
Signal To Noise Ratio
A measurement of noise level in a device compared to the level of the signal. Higher numbers signify a greater difference, which is better. In technical terms, it is the ratio, expressed in dB, of signal power at a reference point in a circuit, to the noise information that would exist if the signal were removed (the noise floor). The maximum signal to noise ratio (equivalent to dynamic range) of a given piece of equipment can be seen as a measure of functional fidelity. This ratio is how much absolute noise it produces, compared to the highest signal voltage it can pass without distortion.
Sound Pressure Level (SPL)
An acoustic measurement of sound energy. 1 dB SPL is the smallest increment in sound level to which the average human is sensitive. Theoretically, 0 dB SPL is the threshold of human hearing while approximately 120 dB is the threshold of pain.
Total harmonic distortion is a measure of the how much a given audio device may distort a signal through the introduction of added harmonics or overtones. These figures are usually given as percentages. THD figures below approximately 1% are inaudible to most people. However, distortion is a cumulative phenomenon, so that if a receiver, equalizer, signal processor, crossover, and amplifier are all rated at "no greater than 1%THD", together, they could produce 5%THD, which may well be noticeable in the perceived sound.
The work of Neville Theile and Richard Small is considered to have the most impact on the loudspeaker design field. They discovered a method that could predict the frequency response performance, and other characteristics of a loudspeaker system, based on its physical parameters.
Three-way (car speaker)
Three-way or triaxial speakers take the separate woofer and tweeter from a two-way design and add a dedicated midrange Driver for enhanced warmth and texture. The extra high-frequency energy also boosts overall Sensitivity.
A non-repeating sound (such as percussion in music) or an abrupt change of voltage. How a speaker handles transients is a good indicator of its performance.
A type of woofer enclosure consisting of a long tube with a woofer at one end, and a port or Passive Radiator at the other. A good low-end reproducer, this design is very compact and generally used in car stereo.
A port tube that can be adjusted in length to provide for optimizing, experimentally, the measured low-end response when a speaker enclosure has not been designed for the woofer Driver installed in it.
A port opening, radiator, or tube whose size is precisely specified by the overall design of the enclosure and woofer.
Highs are reproduced by the tweeter, a small speaker mounted inside the woofer cones of multidriver 2 and 3 way car speakers and separately in other systems. Cone tweeters are efficient and the most economical. Dome tweeters - the type found in most home speakers - have a wider angle of dispersion and more accurate. Some domes are made of metals like neodymium or titanium that yield extended high frequency response. Others are made of Mylar, or a fine cloth like silk and produce a smoother if not as extended response.
Having frequencies above the range of human hearing, commonly considered to be 20 kHz. Not to be confused with "supersonic," which means faster than the speed of sound. Ultrasonic frequencies in the signal path can sometimes cause harmonic distortion in audio components that are in the human hearing range and quite audible.
The tendency of an enclosure to produce no spring or pressure on the woofer. Unloading produces an uncontrollable over-excursion of the woofer cone (it vibrates out of control); the speaker will exhibit inadequate power handling at lower frequencies.
VAS- Volume Acoustic Suspension. A volume of air in an enclosure that has the same resistance characteristic in acoustic terms as the speaker's suspension in mechanical terms. This is a factor taken into account when designing enclosures. It specifies the optimum internal volume of the enclosure.
Vas-Compliance.- A measurement in liters or cubic feet of the volume of air that is equal to the compliance of the speaker's total suspension.
Voltage- Voltage is an electrical charge, or potential difference, between two points, one being of higher relative voltage than the other is. A 1.5-volt 'C' battery has 1.5 volts of difference between the positive and negative terminals, for example. The unit of voltage is called the "volt," named after Allesandro Volta.
Watts- A measurement of power. In speakers, wattage is a term that indicates power-handling characteristics in dealing with electrical voltage inputs from the amplifier. RMS or continuous power handling is the only accurate basis for comparing the capabilities of Drivers. In determining the proper power input for a speaker, use this measure only. So-called Peak Power handling is often only the manufacturers best guess at the power dissipation point, beyond which the unit will fail.
Wavelength- The distance between one peak or crest of a sine wave and the next corresponding peak or crest. The wavelength of any frequency may be found by dividing the speed of sound by the frequency.
Wide-Bit Stream Processing- This technology maintains 20-bit precision through the recording process, for clearer reproduction of delicate, low-level music.
Woofer (Subwoofer)- The bass and lower midrange sounds are reproduced by the woofer. To operate efficiently, a woofer's cone should be made of material that is stiff, yet lightweight. Cones made of polymers, polypropylene, light metals, or poly mixed with other materials including carbon strands and metals, provide excellent sound, and stand up to the heat, cold and moisture that car speakers face daily. Paper cones treated for moisture resistance also do a good job, and are usually very efficient. For car usage, untreated cones should be avoided.
The term "Subwoofer" came into common parlance as a result of the need for marketing departments to boost the "heavy hitting" image of their woofer products. Most such subwoofers are more dependent on the accompanying electronics than on the woofer itself. It was a campaign so successful, it is now as difficult to find a woofer as it is to find a "regular strength" antacid tablet. But as far as describing a particular type of Driver, the term is virtually worthless. The ludicrous extent to which the trend has gone is illustrated in the recent appearance of 4 inch "subwoofers."
Study the ratings, specifications, and construction of any woofer you are considering, to see if will be appropriate for your system. In constructing your system, remember to start with the goal first, then the woofer and enclosure, and finally, the amplifier. Everything must work together, and fit together as one coherent system, if you are to be successful.
One area in which the term "subwoofer" does have some authentic application is in the popularity of dedicated low range speakers called powered subwoofers (usually incorporating an amplifier and Crossover) that are used with home-theatre systems to boost the low-end response.
Xmax- A measure of a speaker cone's maximum Excursion (back and forth motion) in one direction while still maintaining a linear behavior (moving in a straight line with high precision). This factor is measured in inches or millimeters. Xmax is more precisely defined as the width of the voice coil that extends beyond the front plate plus 15%. This relates to how far the speaker can move in either direction without appreciable distortion.
Zero Bit Detection- A circuit in a D/A converter that monitors the digital audio bit stream. upon encountering all bits low, or zero bits, the output of the D/A is disconnected from the preamp. This improves the signal-to-noise ratio specification.
MECP 1ST CLASS
FF08 FASTEST OVERALL TRACK TIME
|11-14-2009, 04:20 AM||#3|
I need BOOOOST!!!!!!
dude holy shit. i just read the first post and skipped the second to say holy shit. kudos to you sir!
focus-power P&P head $1100
focus-power DIY turbo kit $1495
tom's first time in Vegas? PRICELESS!
|11-14-2009, 09:25 AM||#4|
If your local to the 502, 270, 812, 606, 859 area, check out FocusXtreme, the Ohio Valley chapter of FF. Monthly meets and kickass people! Join and POST UP!!!
|11-14-2009, 10:44 AM||#5|
Focus Jr. Enthusiast
Yes, I'm looking forward to reading SquillyB's experience and tips for us with the Focus.
(but I think he needs to be clear when he's writing his own words and when he's just cutting/pasting from other people's work: such as that glossary of terms which appears exactly the same wording all over the internet. We should find the original author(s) and give them credit).
|11-14-2009, 12:14 PM||#6|
4.9L SC Stroker !!!
The problem with that is I will have to list every site on the internet that has a glossary of terms because they are all the same.
I purposely left out hundreds of terms that "standard" car audio listeners will never use or have the need to understand. The terms I have picked to include are all going to be discussed as how they pertain specifically to the Ford Focus.
Take the first term, "Acoustics" I gave you the book definition already, so next we'll speak on "Acoustics" in a Ford Focus. Why do our cars sound the way the do? Acoustics! Everything inside the cabin contributes to or diminishes the acoustic performance of your sound system.
Example: Who here knows what tone will produce the highest level of SPL when all tones are played at the same volume across the tonal spectrum of the human ear inside a Ford Focus. This answer is based solely on the vehicles interior acoustics.
And the answer is, 136 Hz. Not really what someone would listen to while driving around as its not a pretty sounding note, unless, your burping it at a dB drag competition. However also good to know if your building a notch filter to correct for the acoustics in the cabin area, cant run around with the 130Hz range sounding louder than whats below it in the frequency range. So now that we have the answer, and the reason, we could further discuss why this happens. The materials used inside the cabin contribute a lot to the over all acoustics of the cabin. The materials the seats are made out of, the materials the dash is made out of, how many square inches of each type of material will either make the sound appear very "bright" or very "flat". Hard surfaces contribute to making things "bright" while soft, absorbing materials like cloth seats, headliners, etc., will dampen the sound waves or cause them to "decay" faster. If one was to measure the amount of square inches of "hard" materials inside the cabin, as opposed to the number of square inches of "soft" materials, you would see that the Ford Focus has roughly a 85% "soft" and 15% "hard" interior. These figures are gained by actually removing the vehicles interior and measuring the surface area of the materials used. So using this figure to help understand the acoustics of the cabin area you can determine several things.
1- best location for speakers for SPL or SQ
2- best location for subwoofer/subwoofers for either SPL or SQ
3- What tones will play louder do to the natural environment of the cabin area.
And based on that information a user could now go online and view some of the Thiele/Small parameters of the speakers they are considering purchasing and they will be able to predict relatively accurately how they will perform inside the cabin area of the Ford Focus.
This thread is going to be EPIC and HUGE as it will not only give an understanding of the terms I listed according to MECP definition (where most of them come from FYI) but how those terms relate directly to the Ford Focus and a sound system of any type installed in one. I intend to share roughly 4 years of R&D time inside my ZX4. There will be a lot of editing to move some of the information around to try and make it more user friendly as I go.
My end goal is for the average person to be able to sit down and read this thread from beginning to end, understand basic acoustic principals, basic AC/DC voltage, basic installation techniques, basic trouble shooting, and basic system planning. Not only will they understand the basics, but they will be able to apply those basics through graphs, pictures, and documents to their Ford Focus directly.
As far as resources list goes, I have it but it continues to grow so I wont post it till the end. This list of references is not by any means the best list as it does not include everything. I have yet to find a list or glossary on ANY one site that has everything another sites list will have. For example if you go to the12volt.com and go to caraudio.com the glossaries are VERY similar with some definitions being exactly the same some being very different. One list has things the other doesn't and vice versa. I decided my best bet was to only use the answers I found in my Advanced MECP training manual. The definitions I posted above match those in my book and all come from multiple sources, I chose the ones that where worded the best and the quickest for me to find.
If you really want me to offer a complete list of where these references came from your gonna have to help track down those answers. Just because you read it on the12volt.com doesn't mean they wrote it either nor do most sites gives a list of what references they used to create their glossary of terms.
Our example: acoustics, if I needed to list every source I intended to use on the topic of acoustics, I would have to start with the Chinese in 3000 BC tying knots in the strings of their instruments, fast forward to Aristotle in about 360 BC and how he first figured out sound was created by moving air, and then fast forward again to about 30 BC when Vitruvius wrote the first known document concerning the acoustic properties of theater halls. He was the first person to discuss diffraction, diffusion, interferences of echoes and reverberation in regards to sound.
So as far as finding the original authors goes...
here is the link to the website I pulled about 75% of the definitions off of, notice they will also not list references for their glossary.
SO while the thought is kind and genuine to list the authors of the definitions for the glossary its not going to be as easy as you think. My Advanced MECP training guide doesn't even list all the references and I have no time to look up all these on my own.
MECP 1ST CLASS
FF08 FASTEST OVERALL TRACK TIME
|11-14-2009, 12:23 PM||#7|
Focus Jr. Enthusiast
Don't get me wrong: i'm totally looking forward to reading your own contribution to the audio field and how we can improve sound in the Focus. And you are to be commended for compiling a bunch of info others have created as well. Of course sometimes it is hard to find the source for a particular piece. I was just reminding you that it is proper (and technically illegal to not do so) to distinguish between your own words and those of others (even if we can't figure out who those others were, we can simply say, "Here's a standard glossary of terms found all over the internet, original author unknown" or something like that. That way people won't think it was you who wrote it.)
This info is going to be really helpful. Thanks for doing it!
|11-14-2009, 01:29 PM||#8|
4.9L SC Stroker !!!
I was sooo hoping that when I clicked on this you would be like, "sure I'll help ya" cause that would be sweet.
I am not really a writer per say. I try to use at least the quotations to signify someone else's words. When I read your first post I was thinking that, because its what you were thinking at the end of reading the post is why you said that, and I want people to think about the content itself, 'maybe this guy's a writer or English major? could be useful' ;)
So don't get me wrong, I was just trying to say I wouldn't even know where to start to be able to track down the references because my knowledge on some of the subjects dates back to 3000 BC. Granted I am going to limit it mostly to the period from 2005 to currently as because that's where my experience on our particular vehicles was accumulated.
And for the record, the reason I am doing this is because I am no longer competing in ANY Pro Class Car Audio Competitions. If I compete again it will be because there happened to be a show where I was at, and I was bored right then. With out major structural changes to the interior of the vehicle and its electrical system I cannot go any farther with the car itself.
So I figured why not put it ALL out there. Through the years I have dropped bits and pieces to help other people but never really given out everything I know about the focus and designing sound systems for it. And don't hate, think about it, why would I ? Competing in car audio is difficult. Competing in SQi is VERY difficult. Competing in bass boxing is difficult. Competing in both is ALMOST IMPOSSIBLE! Now add the fact that not only was I competing, but I compete in the IASCA Ultimate Class because I work for an Audio shop and I'm a MECP certified Expert installer. Ultimate Class, let me tell you who else competes in Ultimate Class bass boxing from here in town locally;
Rockford Fosgate, MTX, Kinetik, Sony, Pioneer,Hi-Fonics just to name some that you may recognize. They all have local cars that compete regularly here while in between national shows.
Here's a local event... grab a tissue and sit down, if you thought you knew what I meant when I said compete, you aint gotta a clue!
And if you dont know what bass boxing is, its when you play real music to produce the highest SPL not test tones and burping like you would for dB drag type events. So its basically real systems owned by real people, some sponsored some not, playing real music and real SPL levels you would be able to find out on the street.
MECP 1ST CLASS
FF08 FASTEST OVERALL TRACK TIME
|11-14-2009, 01:29 PM||#9|
I need BOOOOST!!!!!!
i think next you need to do a write up called how to build a 5.oh fofo fo less than fo grand.
focus-power P&P head $1100
focus-power DIY turbo kit $1495
tom's first time in Vegas? PRICELESS!
|11-14-2009, 01:39 PM||#10|
4.9L SC Stroker !!!
step #1 - blow current motor while racing WRX
MECP 1ST CLASS
FF08 FASTEST OVERALL TRACK TIME
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