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Car audio and bass cabinet similarities???? No I'm not trying to put those in my cab!

Discussion in 'Amps and Cabs [BG]' started by Matt Call, Jul 22, 2005.

  1. Matt Call

    Matt Call Supporting Member

    Aug 1, 2004
    Minneapolis, MN
    Okay, so I've seen a lot of threads about putting car audio subwoofers into a bass cab. I'm not even remotely interested in that.

    What I'm wondering is, are the basic properties and principles the same? Or even close? I'm considering taking up car audio relatively hardcore (as it were). The thing is, I'd love to be able to build my own cabs someday.

    So basically, I'm wondering how the wiring, impedence, bracing, and everything else like that compares. Any takers?
  2. gilbert46


    Sep 21, 2004
    Sacramento, CA
    I wanna thread-jack on a very similar note.... I need a new 10 for my box. if bass drivers are really 10x better/more sensitive, would it be cool to run a real bass driver in a car? Pretty much like puting a small cab in a car right?
  3. Matt Call

    Matt Call Supporting Member

    Aug 1, 2004
    Minneapolis, MN
    Oooh. Intruiging. Good thread jack. I was worried there for a minute. THat would be awesome if it worked.
  4. mattsk42

    mattsk42 Supporting Member

    You might get a better answer from elitecaraudio.com in their forum. Some of those guys know a lot about imp., wiring, etc, and the difference in home and car. They're a great place for info, too.
  5. Matt Call

    Matt Call Supporting Member

    Aug 1, 2004
    Minneapolis, MN
    Mmmmmm.... span. Me likey.
  6. CrackBass


    Aug 10, 2004
    woofers and subwoofers are very different animals. your typical bass cab 10 will not perform like a good car audio subwoofer. they are louder yes but they lack the deep bass of a sub. there probably is a speaker that would work adequetly (not optimally) but you would have to research it based on the theil parameters of the individual speaker. you might be able to get efficient loud deep bass out of a bass guitar speaker but it would probably require a box bigger than your trunk could hold. everything is a tradeoff in sound. you allways give up something to get something else (size, loudness, bass) but to answer the original poster's question, the rules are the same for both applications, or any sound application. if you know the rules for building a car box, all the same rules apply to bass guitar enclosures, they are just applied differently.
  7. gilbert46


    Sep 21, 2004
    Sacramento, CA
    :) i figured, ive been wanting to ask for a while.
  8. stringtheorist


    Jul 14, 2005
    "Professional" drivers have a shorter excursion, but higher duty cycle. Consumer drivers have a longer excursion (to move more air with less surface area), but at the cost of duty cycle.

    at least that's my understanding.
  9. BruceWane


    Oct 31, 2002
    Houston, TX
    Well, no, "duty cycle" has nothing to do with speakers.

    Pro audio speakers are more efficient than home/car audio speakers, i.e. they produce more db's per watt.

    But home/car audio speakers have a lower frequency range, i.e. they produce more ultra low bass.

    While it may seem that you ought to be able to get both things in one speaker, you just.......can't. High quality speakers of either type operate on the edge of technology. If you get a speaker that goes really low, it won't get loud enough to be useful in a live music situation. When you get a speaker that gets loud enough to work with a live rock n' roll band, it doesn't go low like subs in a car do.

    You can get pretty loud and pretty low, but you start to get in to larger cabinets, and they rapidly become inconvienient.

    So all bass cabs, whether car or home or pro audio, are some combination of a compromise between being loud, low, or small.

    Keep in mind that car audio subs rely pretty heavily on "cabin gain" - i.e. they use the entire interior of the car itself as a sort of cabinet. So while it may seem that with car subwoofers you get a lot of bang out of a fairly small box, in reality the "box" is very large. Once you take car subs out of the car, they lose a LOT of volume.

    edited to add - answering the OP's question.......yes, the concepts of cabinet design and build methods are the same, doesn't matter if it's for your bass or your car or a theater. Get the theile-small parameters for your driver(s), calculate your box size and tuning, then build a good stiff box. The only differences are due to practical matters - you can build home speakers out of MDF (good stuff - but heavy) because you're not going to move them much. You might use fiberglass for car audio boxes because you need to make cabs that conform to odd shapes - but if you used fiberglass for pro audio cabs, they's be heavy as hell and wouldn't stand up to the abuse of multiple load ins and load outs.
  10. Car subs are designed to have a low resonant frequency (Fs), long excursion (Xmax), and high power capacity (Pe). The design is specifically for good performance in a small sealed box located inside an automobile.

    The vehicle cabin provides a bass boost of +12dB per octave. This exactly compensates for the -12dB bass rolloff of a sealed box subwoofer. The net result is flat and very extended bass response. Additionally, the sealed box provides tighter bass than does a vented box.

    The inefficient part (low sensitivity) comes from the designer making the resonant frequency quite low, plus operating in a small box. In this case, he chose Low + Small, and sacrificed Loud. Pick any 2, cannot have all 3 in the same box.

    The maximum amount of noise the driver can make is a function of its displacement. If a 10" displaces 100 mL and a 15" sub displaces 500 mL, the 15" will make more noise. Displacement = Piston Area * Xmax. Efficiency is how much power is required to reach Xmax. Cone excursion increases 4x for every octave lower at the same loudness level, so a long Xmax is required for high SPL at low frequencies.

    True subwoofers are also specialized drivers, meaning they do not respond very high up the scale. Mine are all done above 100 Hz. This is not a problem when used with a crossover at 80 Hz, but they completely suck as full range bass drivers. So does a tweeter for that matter... or anything else used for a job it was not designed to perform.