Internet Info 1994 March/Internet Info CD-ROM (Walnut Creek) (March 1994).iso/answers/rec/car-audio/part3

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From: [e-mail] (Jeffrey S. Curtis)
Newsgroups: rec.audio.car,rec.answers,news.answers
Subject: rec.audio.car FAQ (part 3/3)
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Date: 6 Apr 1994 05:47:18 GMT
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Summary: This article describes the answers to the frequently
     asked questions on the rec.audio.car newsgroup.  This
     article is posted once per month.
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Xref: bloom-beacon.mit.edu rec.audio.car:14905 rec.answers:4774 news.answers:17722

Archive-name: car-audio/part3
Rec-audio-car-archive-name: FAQ/part3
Version: 2.1
Last-modified:  5 Apr 94


      5 Installation

    This section describes how to do what you want once you know
    what it is you want to do.

    5.1 Where should I buy the components I want? [JSC]

    Most of the time, you will either buy from a local dealer, or
    from a mail-order house.  Buying from a local dealer can be
    good because you get to deal directly with a person: you can
    show them your car, ask specific questions, haggle prices, get
    quick service when there are problems, get deals on
    installation, etc.  But there can also be advantages to buying
    mail-order: generally cheaper prices, sometimes better service,
    etc.  In either case, you should always check prices before you
    buy, inquire about warranty service, and ask about trial
    periods.

    5.2 What mail-order companies are out there? [JSC,JM,MM]

    Crutchfield             800/955-3000
    1 Crutchfield Park
    Charlottesville, VA 22906 USA

    Advantages: great customer service; generally knowledgeable
            sales and tech support personnel; custom mounting
            kits, wiring harnesses, etc. free of charge.

    Disadvantages: limited product line; generally higher prices
               than local shops.


    J.C. Whitney            312/???-????
    ?
    Chicago, IL 6060? USA

    Advantages: 10kW amps for $19.99

    Disadvantages: 10kW amps that really only put out 1mW and break
               after first 10 minutes of use.


    Parts Express           800/338-0531
    340 E. First St.
    Dayton, OH 45402 USA

    Advantages: large selection of electronics supplies at
            respectable prices.  Showroom prices said to be
            better than catalog prices.

    Disadvantages: also carries some of the same quality-level
               components as J.C. Whitney.


    Classic Research/Z-Box    602/571-0171
    5070 E. 22nd St.
    Tucson, AZ  85711

    Advantages: creates custom door panels with car audio in mind.

    Disadvantages: only services expensive sports and luxury cars.


    MCM Electronics         800/543-4330
    650 Congress Park Drive
    Centerville, OH 45459-4072

    Advantages: sells lots of decently priced trinkets (fuses, fuse
                holders, wire, etc.) and has excellent service and
                available technical support.

    Disadvantages: ?

    5.3 What tools should I have in order to do a good installation? [JSC]

    Electrical tape - lots of it.  Make sure you get some that can
    withstand extreme temperature ranges.

    Wire cutters/strippers and crimpers.  Get a big pair with
    stripper holes precut for individual wire sizes.

    Angled screwdrivers.  Makes taking dash and rear deck speakers
    out a lot easier.

    Multiple size screwdrivers, both flathead and Phillips.
    Magnetic screwdrivers can be a big help when trying to get
    screws into (or out of) tight spaces.

    Various wrenches, pliers, and socket sets, depending on your
    vehicle.

    Metal drill and saw.  You'll need these if you need to modify
    your vehicle for new speaker cutouts or to accommodate a new
    head unit.

    Hot glue gun.  Good for putting carpeting or door panel trim
    back in place after modifications.

    Razor knife.  Helps for detailed modifications of door panels
    or carpeting, especially when installing new speakers.

    Wire.

    Shrink wrap or flex tubing.  Good for protecting wire,
    especially in the engine compartment.

    Multimeter.  Helps to diagnose installations.

    Extra hardware (screws, nuts, bolts, connectors, etc.).

    Fuse puller and extra fuses.

    Wire ties.  Helps to tuck wire away in otherwise exposed
    areas.

    Small light source.  A flashlight will do - you just want
    something that you can poke around the innards of your car
    with.

    Tape measure.

    5.4 Where should I mount my speakers?

    5.5 What is "rear fill", and how do I effectively use it? [HK,JSC]

    Rear fill refers to the presence of depth and ambience in
    music.  A properly designed system using two channels will
    reproduce original rear fill on the source without rear high
    frequency drivers.  Since recordings are made in two channels,
    that is all you will need to reproduce it.  What is captured at
    the recording session (coincident pair mics, Blumlein mic
    patterns, etc.) by a two channel mic array will capture the so
    called "rear fill" or ambience.  Many of the winning IASCA
    vehicles have no rear high frequency drivers.  Also a lot of
    this has to do with system tuning.  If rear high frequency
    drivers are added, however, the power level of the rear fill
    speakers should be lower than that of the front speakers, or
    else you will lose your front-primary staging, which is not
    what you want (when was the last time you went to a concert and
    stood backwards?).  The proper amount of amplification for rear
    fill speakers is the point where you can just barely detect
    their presence while sitting in the front seat.  Separates are
    not a requirement for rear fill; in fact, you may be better of
    with a pair of coaxial speakers, as separates may throw off
    your staging.

    5.6 How do I set the gains on my amp? [JSC]

    The best way to do this is with a test tone and an
    oscilloscope.  Since most people have neither item, the
    following will work approximately as well.

      1) Disconnect all signal inputs to the amp
      2) Turn all sensitivity adjustments as low as possible
     3) Turn head unit on to around 90% volume (not 100% or else
        you'll have head unit distortion in there - unless you've
        got a good head unit) with some music with which you're
        familiar, and with EQ controls set to normal listening
        positions
      4) Plug in one channel's input to the amp
      5) Slowly turn that channel's gain up until you just start
        to notice distortion on the output
      6) Turn it down just a wee little bit
      7) Disconnect current input
      8) Repeat steps 4-7 with each input on your amp
      9) Turn off head unit
    10) Plug in all amp inputs, and you're done

    If by some chance you do have an oscilloscope (and preferably a
    test disc), you do essentially the same thing as above, except
    that you stop turning the gains up when you see clipping on the
    outputs of the amplifier.

    Note that if you are paralleling multiple speakers on a single
    amp output, you need to set the gains with all of the speakers
    in place, since they will be affecting the power and distortion
    characteristics of the channel as a whole.

    5.7 How do I select proper crossover points and slopes?

    5.8 How do I flatten my system's frequency response curve?


      6 Competition

    This section describes the competition branch of the car audio
    world - what it is, and how to get involved.

    6.1 What is IASCA, and how do I get involved? [JSC,HK]

    IASCA is the International Auto Sound Challenge Association, a
    sanctioning body for car audio competitions held throughout the
    world.  Competitors earn points at each competition, and those
    that perform the best each year can advance to the finals.
    Prizes (trophies, ribbons, and sometimes cash) are usually
    given out to the top competitors in each class at every
    competition.

    There are registration forms for IASCA in every issue of Auto
    Sound and Security (see 7.1).

    6.2 What is USAC, and how do I get involved? [HK]

    USAC is another sanctioning body, similar to IASCA.  However,
    USAC places greater emphasis on SPL measurements than IASCA.

    6.3 What are the competitions like? [HK,CD]

    [HK writes:]

    They are much like loud car shows: a lot of cars parked with
    their hoods/doors/trunks open showing their audio systems.
    There are two types of judging styles: 1) drive through - where
    competitors drive their own vehicles to judging stations to be
    judged, and 2) walk-arounds - where the teams of judges will
    walk around the event site and judge vehicles that fit within
    their judging assignments.  Typically SPL is done first with
    the mic stand in the driver's seat and the competitor in the
    passenger side adjusting only the volume.  Hearing protection
    must be worn.  After SPL measurements are completed, RTA
    measurements are performed by playing pink noise.  When the
    volume level is within the specified "window" around
    90db-110db, the RTA judge will signal you out, and at that
    point you must exit the vehicle for the actual scoring
    measurements.  The next area for judging should be sound
    quality where two judges will sit in your car and judge the
    sound quality based on IASCA's reference CD/tape.  The next
    area is installation judging where the competitor has 5 minutes
    to explain and show the installation of his/her vehicle.  It is
    very useful to have a picture book/album of photos of the
    installation that may not be visible to prove that items not
    visible do exist.  When that is completed, the competitor can
    park the vehicle and show spectators the vehicle.  These
    procedures may differ from show to show, and at the
    regional/final levels they are very strict in what can and
    can't be done, e.g. a judge will make sure no adjustments are
    made after SPL until after sound quality judging is over, ear
    protection, etc.

    [CD writes:]

    Most involve a lot of waiting around.  Thus, they are perfect
    for meeting other people interested in car audio, and seeing
    some installations which may give you some ideas.  They're also
    perfect for listening to some cars that sound a lot better and
    a lot worse than your own.  In IASCA competition, the cars are
    judged on:

      Sound Pressure Level (30pts)
      Frequency Response (40pts)
      Staging (40pts)
      Stereo Image (40pts)
      Frequency Separation/Clarity (40pts)
      Sound Linearity (20pts)
      Absence of Noise (40pts)
      Ergonomics (20pts)
      Wiring/Electrical System Cosmetics and Integrity (35pts)
      Cosmetic Integration Consistency (40pts)
      Component Installation Integrity (55pts)
      General Creativity (20pts)
      Attention to Detail (15pts)

    6.4 Should I compete? [CD]

    You should compete if:

    a) You have an ok sounding stereo
    b) You have an ok installation (i.e. no amps/changers sliding
       around in the trunk)
        c) You'd like some pros to comment on your system
    d) Your feelings won't get hurt if you don't get first
    e) You've been to a contest and talked to competitors about it
    f) You've read the IASCA rulebook
    g) You've listened to the IASCA Test Disc in your car, and
       understand what the sound quality judges are listening for

    You can compete even if you don't do all of the above, but the
    recommendations will help you understand and gain the most from
    competing.

    6.5 What class am I in? [HK,JSC]

    [HK,JSC write:]

    There are three classes: novice, amateur, and pro.  The novice
    class is intended to be an unintimidating level where beginners
    can start out; however, a competitor may only be in the novice
    class for one year, at which time he is automatically moved to
    the amateur class.  Most competitors stay in the amateur class
    indefinitely, unless they become affiliated with a car audio
    shop or manufacturer, at which point they are moved into the
    pro class.

    [CD writes:]

    Are you or were you employed by a car audio manufacturer or
    dealer?
      Yes:  You compete in pro
       No:  Is this your first year of competing?
              Yes:  You compete in novice for the first year
               No:  You compete in amateur

    Note that modifying your amplifiers, buying your equipment
    below retail, or being sponsored by a manufacturer or dealer
    will get you kicked into pro.

    Also note that any home built active gear in the signal path
    (e.g. custom built equalizers, crossovers, or noise gates) will
    get you kicked out of novice.

    Once you know what group you are, you next need to know what
    power category you are in.  Add up the 4-ohm non-bridged rating
    of all your amplifiers, including your head unit if your head
    unit is powering speakers (rather than exclusively feeding
    amplifiers).  Then, find the category you fit into:

    Novice:  1-50  51-100  101-250  251-500  501+
    Amateur: 1-50  51-100  101-250  251-500  501-1000 1000+
    Pro:        1-100      101-250  251-500  501-1000 1001+

    Thus, if you had a Rockford Punch 40 (20Wx2) and a Punch 60
    (30Wx2), with a head unit that put out 6Wx2 (powering, perhaps,
    a center channel) you're in the 101-250 class.  It does not
    matter if your amps are bridged down to .002 ohms; it's only
    the 4ohm rating that counts.  If you no longer used your head
    unit to power speakers, you would be in the 51-100 class (or
    the 1-100 class if you were a pro).

    Competition is usually most viscious in the 101-250 and 250-500
    categories at typical contests.


      7 Literature

    This section describes various literature which you can read to
    brush up on your car audio skills, or to keep current, or to
    see other people's installations, or whatever else you'd like.

    7.1 What magazines are good for car audio enthusiasts? [JSC,MI,NML]

    Car Audio and Electronics   $21.95/year
    P.O. Box 50267              (12 issues)
    Boulder, CO 80321-0267      800/759-9557

    Car Stereo Review           $17.94/year
    P.O. Box 57316              (6 issues)
    Boulder, CO 80323-7316      303/447-9330

    Auto Sound and Security     $28.95/year
    P.O. Box 70015              (12 issues)
    Anaheim, CA 92825-0015      714/572-2255

    Car Hi-Fi                   #23.60/year
    Freepost                    (8 issues)
    TK660                       081 943 5943
    Leicester
    KE87 4AW

    7.2 Are there any newsletters I can read? [MO,HK]

    Autosound 2000 Tech Briefs  $35.00/year
    2563 Eric Lane, Ste D       (6 issues)
    Burlington, NC 27215        800/795-1830

    7.3 What books can I read? [JSC,JW,TT]

    Loudspeaker Design Cookbook
    by Vance Dickason
    Published by Audio Amateur
    ISBN 0-9624191-7-6
    $25-$30

    Designing Speaker Enclosures
    by David Weems
    Published by ?
    ISBN ?
    $??.??

    Killer Car Stereo on a Budget
    by Daniel L. Ferguson
    Published by Audio Amateur Press
    ISBN 0-9624191-0-9
    $19.95


      8 Credits

    [JSC] Jeffrey S. Curtis ([e-mail])
    [JLD] Jason Lee Davis   ([e-mail])
    [MI]  Matt Ion          ([e-mail])
    [JW]  Jerry Williamson  ([e-mail])
    [CD]  Cal Demaine       ([e-mail])
    [MO]  Mark Obsniuk      ([e-mail])
    [HK]  Harry Kimura      ([e-mail])
    [RDP] Dick Pierce       ([e-mail])
    [BG]  Brian Gentry      ([e-mail])
    [JM]  Jeff Meyers       ([e-mail])
    [MH]  Marvin Herbold    ([e-mail])
    [TT]  Trevor Tompkins   ([e-mail])
    [MM]  Matthew E. Meiser ([e-mail])
    [NML] N. M. Lines       ([e-mail])

--
Jeffrey S. Curtis - [e-mail] <> "You say these days are made of rust:
Network Coordinator - UI Housing Div <> ``Counted out! Counted out in loss!''
   Proton    <  Dodge  >   Pioneer   <> I've got plans to prove them wrong.."
Phase Linear < Stealth > StreetWires <> -- INXS _Full Moon Dirty Hearts_ 1993