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Car Audio FAQ

Frequently Asked Questions in the rec.audio.car

This is the FAQ list for the Usenet newsgroup rec.audio.car, maintained by Ian D. Bjorhovde , with contributions from many other people (see Section 8). The contents of this document are based on the contributors' opinions; neither the contributors nor the FAQ maintainer accept any responsibility or liability for any damages brought about by the information contained herein.

This document may be freely distributed and reproduced as long as it remains wholly unaltered and includes this notice. If you do redistribute this document, especially on a commercial basis, please contact the FAQ maintainer before doing so.

If you have suggestions for improvements to this document, or if you fail to understand any part of it, please feel free to send a note to the FAQ maintainer or to the author of the relevant section. The initials of the author(s) of each section can be found in brackets following each question.

This document is posted once per month to the Usenet newsgroups rec.audio.car, rec.answers, and news.answers, and is available via anonymous FTP from:

It is also available on the World Wide Web (WWW) and can be accessed using the URL

If you do not have access to FTP or a WWW client (such as Mozilla or Internet Explorer) and cannot find the FAQ on any of the aforementioned newsgroups, you can obtain the FAQ via email by sending email to with the following three lines in the message body:

`send usenet/rec.audio.car/FAQ/part1' `send usenet/rec.audio.car/FAQ/part2' `send usenet/rec.audio.car/FAQ/part3' `send usenet/rec.audio.car/FAQ/part4' `send usenet/rec.audio.car/FAQ/part5'

Note that the rtfm.mit.edu server is a very popular machine, and accordingly, responses to requests may be slow, especially via the mail-server. Please be patient when using this service.

-1.0 Definitions
-1.1 What do all of those acronyms mean? [JSC]
-1.2 What is meant by "frequency response?" [JSC]
-1.3 What is a "soundstage?" What is an "image?" [CD]
-1.4 What is meant by "anechoic?" [JSC]
-2.1 My speakers make this high-pitched whine which matches the engine's RPMs. What is it, and how can I get rid of it? [IDB]
-2.1.1 Level 1: Check out the Amplifier(s)
-2.1.2 Level 2: Reduce the System
-2.1.3 Level 3: Move the Head Unit
-2.1.4 Level 4: Testing the Car
-2.1.5 Level 5: Adding Signal Processors
-2.1.6 Level 6: Processor Isolation Tests
-2.2 My system "pops" when I turn it off. What is happening and how can I get rid of it? [JD]
-2.3 What is the best power wire to use? [JSC]
-2.4 What is the best speaker wire to use? [JSC, JW]
-2.5 I heard that I should run my power wire directly to my car's battery. Why should I bother, and how do I do it? [JSC]
-2.6 Should I do the same thing with my ground wire, then? [JSC, IDB]
-2.7 Sometimes when I step out of my car, I get a really bad shock. What is wrong with my system? [IDB]
-2.8 When my car is running and I have the music turned up loud, my headlights dim with the music. Do I need a new battery or a new alternator? [CD, MO]
-2.9 What is a "stiffening capacitor", and how does it work? [JSC]
-2.9.1 Do I need a capacitor? [MZ]
-2.9.2 Can I just upgrade my headlight wiring instead? [MZ]
-2.9.3 Will the dimming go away if I upgrade the amplifier power/ground wiring? [MZ]
-2.9.4 What do I look for when buying a capacitor? [MZ]
-2.9.5 How do I install a capacitor? [MZ]
-2.9.6 I have more than one amp in my audio system. Which one should I have the capacitor run? [MZ]
-2.9.7 Will my bass response improve by adding a capacitor? [MZ]
-2.10 When should I upgrade my battery or add a second battery? [IDB]
-3.0 Components
-3.1 What do all of those specifications on speakers mean? [JSC, CD]
-3.2 Are component/separates any better than fullrange or coaxials? [JSC, DK]
-3.3 What are some good (and bad) brands of speakers? [JSC]
-3.4 What do all of those specifications on amplifiers mean? [JSC, BG]
-3.5 What does "bridging an amp" mean? [MHa]
-3.5.1 Why should I bridge my amp?
-3.5.2 Why shouldn't I bridge my amp?
-3.5.3 What happens when an amp is bridged?
-3.5.4 Does bridging an amp would halve the impedance of the speakers?
-3.5.5 Can I bridge my 4 channel head unit?
-3.6 What is "mixed-mono?" Can my amp do it? [JSC, IDB]
-3.7 What does "two ohm stable" mean? What is a "high-current" amplifier? [JSC]
-3.8 Should I buy a two or four (or more) channel amplifier? [JSC]
-3.9 What are some good (and bad) brands of amplifiers? [JSC, IDB]
-3.10 What is a crossover? Why would I need one? [JSC]
-3.11 Should I get an active or a passive crossover? [JSC, JR]
-3.12 Should I buy an equalizer? [JSC]
-3.13 What are some good (and bad) brands of equalizers? [HK]
-3.14 What do all of those specifications on tape deck head units mean?
-3.15 What are features to look for in a tape deck?
-3.16 What are some good (and bad) brands of tape decks?
-3.17 What are features to look for in a CD head unit?
-3.18 Should I buy a detachable faceplate or pullout CD player? [IDB]
-3.19 What are some good (and bad) brands of CD head units? [HK]
-3.20 Can I use my portable CD player in my car? Won't it skip a lot? [JSC]
-3.21 What's that weird motor noise I get with my portable CD player? [JSC]
-3.22 What are some good (and bad) brands of portable CD players?
-3.23 What's in store for car audio with respect to MD, DAT and DCC? [HK]
-3.24 Are those FM modulator CD changers any good? What are my other options? [PW, JGr]
-3.25 What kind of changer will work with my factory head unit? [PO]
-3.26 What are some good (and bad) brands of CD changers?
-3.27 Why do I need a center channel in my car, and how do I do it? [HK, JSC]
-3.28 Should I buy a sound field processor? [DK]
-3.29 What are some good (and bad) brands of signal processors? [IDB]
-3.30 I keep hearing that speakers for Company X are made by Company Y. What's the deal? [IDB, DK]
-3.31 What is a Line Driver? Do I need one? [LC,IDB]
-3.32 Can I play MP3 files in my car? [AK]
-4.0 Subwoofers
-4.1 What are "Thiele/Small parameters?" [CD, RDP]
-4.2 How does speaker sensitivity affect real world SPL? Will a higher sensitivity give me a larger SPL? [MS]
-4.3 What are the enclosure types available? [JLD, JG]
-4.4 Which enclosure type is right for me? [IDB, DK]
-4.4.1 Infinite Baffle ("free-air")
-4.4.2 Sealed Box
-4.4.3 Ported Box
-4.4.4 Bandpass Box
-4.5 How do I build an enclosure? [AO]
-4.6 MDF for Dummies [IDB]
-4.6.1 What is MDF? [PS]
-4.6.2 Where can I get MDF? [PS]
-4.6.3 What type of saw blade works best when cutting MDF? [PS]
-4.6.4 What type of router bits work well with MDF? [PS]
-4.7 What driver should I use?
-4.8 Is there any computer software available to help me choose an enclosure and a driver? [JSC, MH, DK]
-4.9 What is an "aperiodic membrane?" [CD, DK]
-4.10 Can I use my subs in the winter? [MS]
-4.11 How can I carpet my enclosure? [AO]
-4.12 Are large magnets always better than small magnets? [ST]
-4.13 I know the box volume required for my subwoofer, but what are the best dimensions for my enclosure? [IDB]
-5.1 Where should I buy the components I want? [JSC]
-5.2 What mail-order companies are out there? [JSC, JM, MM, IDB]
-5.3 What tools should I have in order to do a good installation? [JSC]
-5.5 What is "rear fill", and how do I effectively use it? [HK, JSC]
-5.6 How do I set the gains on my amp? [JSC]
-5.7 How do I select proper crossover points and slopes? [DK]
-5.8 How do I flatten my system's frequency response curve? [IDB, DK]
-5.9 How do I wire speakers "in series" and "in parallel?" [IDB]
-5.10 Are there any alternatives for Dynamat? It's too expensive! [MM, PK]
-5.11 How many devices can I attach to my remote turn-on lead? [IDB]
-5.12 How do I wire a relay in my system? [IDB]
-5.13 How do I design my own passive crossovers? [JSC, JR]
-5.14 How do I build my own passive crossovers? [JSC]
-5.15 Can I split the single pre-amp output from my head unit to drive two amplifiers with a Y-cable? [IDB]
-5.16 How do I turn a stereo signal into a mono signal [BW]
-5.17 How do I determine a speaker's polarity? [IDB]
-5.18 How can I use an oscilloscope to set the gains in my system? [AO]
-5.19 Why are kickpanels such a popular location for mounting speakers? [ES]
-5.20 How can I build custom kickpanels? [MB]
-5.21 What's worse for a speaker, too much or too little power? [IDB]
-5.22 Why is distortion harmful to my speakers? [RK]
-5.23 What tools do I need to cut Plexiglas? [PS]
-5.24 Are there any other special requirements for working with Plexiglas? [PS]
-6.1 What is IASCA, and how do I get involved? [JSC, HK, IDB]
-6.2 What is USAC, and how do I get involved? [HK]
-6.3 What are the competitions like? [HK, CD, IDB]
-6.4 Should I compete? [CD]
-6.5 What class am I in? [HK, JSC]
-6.6 Where can I find out when these Sound-Offs are? [IDB]
-6.7 How do I get sponsored by a manufacturer? [CM]
-7.1 What magazines are good for car audio enthusiasts? [JSC, MI, NML, JR]
-7.2 Are there any newsletters I can read? [IDB]
-7.3 What books can I read? [JSC, JW, TT]
-7.4 Can I contact any manufacturers on-line? [IDB]
-8.0 Credits

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