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Car deck and subwoofer

By Svoboda
Mar 31, 2003
  1. i don't know if the people here can help me with this question as it is more car audio, but i'm hoping you guys can!!!

    so i have this deck
    http://www.epinions.com/613422_Alpine_CDM_7857_CD_Receiver/display_~full_specs
    and it says it has two preout amp places but no preout sub place. Does this mean the deck can't support a sub? if it has amps, why not a sub?

    if it can't is there anyway i can hook up a sub to it? my friend told me about somehting you can add to the actual amp, but he didn't know much about it.

    any help is greatly appreciated, thanks
     
  2. poertner_1274

    poertner_1274 secroF laicepS topShceT Posts: 4,172

    You will just have to add a lowpass filter. That will filter out all of the high sounds to only send the low bass to the subs. I don't think it will be a big deal to just hook the amp up to the subs directly. If you have a NICE system then you will want the filter, but otherwise I personally don't think it is a big deal. Your sub will just try to play the higher notes and will sound a little garbled, but you can try it and see how you like it. If you don't, then add the filter.
     
  3. Svoboda

    Svoboda TS Rookie Topic Starter Posts: 70

    haha well i just actually cracked the manual and found a way to turn on and off some kind of sub control. it gives you sub volume (maybe bass?) control. so i guess that would work?

    also poertner i am going to get a friend to help me put this stuff in but i don't know if he and i together know everything. i've looked at crutchfield.com for some instructions, you know of any other websites/forums devoted specifially to installing car audio systems?
     
  4. StormBringer

    StormBringer TS Rookie Posts: 2,244

    You will still want to use a filter to get rid of the higher frequencies, most subs are rated between certain frequencies, usually pretty low. You can damage the coils by running higher than rated, or lower than rated frequencies through them.
     
  5. poertner_1274

    poertner_1274 secroF laicepS topShceT Posts: 4,172

    Thanks for clarification SB, I was unsure, as my deck has sub outputs. I'll check around and try to find a good website. But it might take me a day or so, as I have a LOT of schoolwork to do this week.
     
  6. Elcarion

    Elcarion TechSpot Paladin Posts: 169

    There are several ways that you could hook a sub or subs to your system. Do you have an external amp? If so, what make and model is it? Do you plan to purchase an additional amp to power your sub woofer?
    The "something you add" to your system is called a crossover. There are two kinds of crossovers: active and passive. Active crossovers are installed before the amplifier while passive crossovers are installed after the amplifier. Most crossovers offer both low-pass and high-pass features. Active crossovers are 1) More expensive, 2) Provide better sound quality, and 3) Usually provide more tweaking ability as compared with passive crossovers. In the passive crossover realm you have two basic components: 1) capacitors - these are high-pass filters and 2) Coils - these are low-pass filters. The cheapest solution for you might be to put a coil on each sub to filter the high freqencies off (low-pass). It's not the best sounding solution. You should talk to a local car audio shop to see what options you have.

    Most new Alpine receivers have a bass management feature that works with Alpine amplifiers having the same feature. This may be what you found in the manual.
     
  7. Svoboda

    Svoboda TS Rookie Topic Starter Posts: 70

    on my deck if push down a certain button it will say subwoffer on or something like that.

    then under the same menus where i can adjust the bass, fader etc there is a new menu called subwoffer, that can go from -15 to +15 any idea what that does?

    right now my deck's amp is driving my 4 speakers and i am going to get an external amp (probably 250 rms bridged at 4 ohm) for the single woofer i am going to get
     
  8. StormBringer

    StormBringer TS Rookie Posts: 2,244

    the one that goes from -15 to +15 sounds like a gain control. If you are going to get an external Amp for5 the subwoofer, you won't need to worry about any of that anyway. You should have low level outputs jacks(the RCA jacks on the back of the unit) which you will connect to the Amp. Usually, the output on the low level output is within tolerence of most subs, unless you have a specialized sub, then you'll need to check the frequency range of the sub, and the range of the low level out.
     
  9. Svoboda

    Svoboda TS Rookie Topic Starter Posts: 70

    i was thinking about getting the the stuff off of ebay but most of the amps on there are brand x crappy ones. and other the other stuff is sooo expensive it would cost like 400 bucks to get all the stuff. anyone have any ideas of a good website with really good deals on car audio? crutchfield.com is really expensive
     
  10. Elcarion

    Elcarion TechSpot Paladin Posts: 169

    No, low level outputs are simply not amplified to listening levels; they are full range in frequency. The "low" does not refer to the freqency range of the outputs in any way. Svoboda already stated that he does not have a sub woofer output; this IS a low level output that is filtered to only send low frequency output to an external amp. I think you are confusing the term low level with low frequency.
    Yes, Svoboda should worry about filtering high frequencies from the subs. No, he does not necessarily need to do so if he 1) Does not care about the added distortion and 2) The subs are not run near their rated power limit. Sub woofers have very large coils. Because of this is takes a combination of high power to damage them. Tweeters on the otherhand are very susceptible by damage from distortion due to their very small voice coils.
     
  11. Elcarion

    Elcarion TechSpot Paladin Posts: 169

    The cheapest place that I've found for name brand components is: http://www.carmedia1.com/ . An alternative is local pawn shops; consider their return policy.
    I looked your receiver up. It appears to have Alpine's proprietary BassEngine(tm) feature. This provides for subwoofer level control and Bass center frequency control when used with a complimentary Alpine external amplifier with BassEngine(tm). Be sure to buy an amplifier with a built-in low pass crossover. Then you don't need to worry about most of the crossover discussion.
    The Alpine MRV-T320 2-channel amplifier is $189. It has both BassEngine(tm) and built-in crossover. Bridged output at 4ohms is 400W. You should be able to find a 12" subwoofer, that can handle 400W, in the $110-150 range on the low end. You'll need to purchase or build a box for the subwoofer. Add power cable, rca cables, and speaker wire.
    You're not likely to find new, quality components under $400. Car audio is not a cheap hobby! Good luck!
     
  12. Nic

    Nic TechSpot Paladin Posts: 1,549

    Personally, I wouldn't bother with a subwoofer for your car, unless you wish to damage your hearing. You can get much better sound quality by fitting good speakers with large bass cones. A sub is really only usefull to impress your friends with, but if thats what you're after then good luck!:p
     
  13. poertner_1274

    poertner_1274 secroF laicepS topShceT Posts: 4,172

    Heh Nic, to tell you the truth, I used to have a decent setup in my old car. Nice Bose speakers, but then I decided to get 2 12" subs and it was worth every penny. The sound is so much better, it is unbelievable. My setup is a little more than I need, but I got it all on a good deal from a friend.

    But yes it gets VERY VERY loud, but I don't mind, I like my music loud and sounding good. I'll worry about my hearing later ;)
     
  14. Nic

    Nic TechSpot Paladin Posts: 1,549

    I don't know if you are fully aware of how *dangerous* it can be to turn up the volume of a subwoofer in a confined space such as a car. You really can burst your eardrums quite easily (especially if the windows are up), as the sound will not seem as loud as it really is. Also, I've heard some truly superb systems that don't use subs at all, and are aimed at HiFi buffs. Yes, it can be good to actually *feel* bass notes running down your spine as you drive along, but a good set of quality speakers (8" cones or greater) can provide plenty of bass without the potential of serious injury. If you take a look at top end HiFi systems, you won't find ANY that include a subwoofer, as most HiFi buffs (i.e. the ones that don't care about impressing others with wattage) really prefer realism over bass power. Most users that have subwoofers fitted are more interested in impressing their friends rather than listening to music. I guess its really up to the individual and what they really want from their system.
     
  15. poertner_1274

    poertner_1274 secroF laicepS topShceT Posts: 4,172

    I agree with you 100 percent. I dont' have the money to get the hi-tech stuff, so I take what I can get for cheap. And that is how I got my subs.

    As far as ear problems go, I know exactly how bad it can be, as I have problems already from music.

    But it's all up to the individual as you have said. I'm sure I'll grow out of it soon, but for now it will be loud and deep.
     
  16. Svoboda

    Svoboda TS Rookie Topic Starter Posts: 70

    yea you guys thanks for all the help. i got an amp with a low pass filter and from reading all the stuff you wrote, it would seemt then that it doesn't matter that my deck doesn't have a specific sub preamp out, correct?

    elcarion said this:This provides for subwoofer level control and Bass center frequency control when used with a complimentary Alpine external amplifier with BassEngine(tm)

    can one of you explain the bass center frequency control thing? i found it on my deck but hav no idea what it does and the manual is no help. the amp i got is 300 w rms, and the sub is only 250 rms. my car is a honda, and i dont' want to break the alternator. is this 50 watt differnce going to hurt anything?


    and yes the sub is both for impressing friends, and listening purposes.
     
  17. Nic

    Nic TechSpot Paladin Posts: 1,549

    That 'bass center frequency control thing' sounds like it adjusts the centre frequency at which the bass is boosted by the bass level control. You'll want to adjust this so that you get natural sounding bass, without any bass boom. Use the level control to help adjust the volume of the bass sounds to blend with your other speakers. Normally you would want to set the bass centre frequency as low as possible so that bass sounds don't appear to come directly from the sub, but instead enhance the sound of the other speaker units.

    As far as wattage difference goes, this is not important as you use the sub level control to adjust the output to a level that matches your other speakers.
     
  18. Svoboda

    Svoboda TS Rookie Topic Starter Posts: 70

    yea so i got all the stuff finally in the mail, but now i don't know what gauge of speaker wire to get. The stuff to my amp is 8 gauge, but does the thickness for the speaker wire matter? also do any of you know of any good brands. I'll prolly be getting this stuff from my local radio shack.

    thanks
     
  19. poertner_1274

    poertner_1274 secroF laicepS topShceT Posts: 4,172

    I personally don't feel the need to spend a TON of money on speaker wire. I might not be as much of an audiophile as the rest, so I feel that regular wire would work just fine. Others might disagree, but for the price of Monster Cable I don't think it is worth it. As long as it isn't the smallest cheapest stuff you can find you will be ok.
     
  20. Nic

    Nic TechSpot Paladin Posts: 1,549

    Speaker wire is important as it will play a large part in determining the sound of your system. Thin wire tends to make things sound thin, trebly, and lifeless, whereas thicker wires tend to produce full well balanced sound with good bass. There's really a lot more to this than I can write about here so go visit some good HiFi review sites to get you started. Also, you may find that the guage of wire you use will likely be determined by how easily you can route the wires round your vehicle.

    Here's one link to get you started ...

    Choosing the Best Cable for your Application

    PS: It is possible to get good sounds with cheap cable, but it all depends on how well they match the system they are attached to. As long as you get cable that was designed for the purpose, and is of reputable quality, then it'll be fine. Just don't use bell-wire.
     
  21. olefarte

    olefarte TechSpot Ambassador Posts: 1,343   +6

    I agree with almost everything Nic has said in this thread. Most so called speaker wire that you will get at Radio Shack or Wal Mart is going to be 18 guage. For just a little bit more thay will have no name wire that is, I think 12 gauge. I think if you compare the two, you will be much happier with the heavier wire. I've always used Monster Cable in my car and home system and it's very good.

    As to some who say you don't need a subwoofer, I know I sure couldn't do without one. If you are playing CD's and don't have one, you aren't hearing the lowest end on the CD. And when you first get your sub hooked up, you'll want to turn it up so you can hear it, but as time goes by you'll turn it down to a normal level. And I agree, you can hurt your ears if you play your system to loud, but you don't have to play it loud to hear a quality sub.
     
  22. Svoboda

    Svoboda TS Rookie Topic Starter Posts: 70

    ok hopefully this will be my last question:

    how do i determine what i should set the crossover at on my sub?
    from some research it would seem as if the crossover seperates it into two signals, for my satelities and subwoofer.

    the crossover on my amp goes from 40-130 hz. do i need to determine the frequency that my satelites can put out and then set the crossover or what?
     
  23. olefarte

    olefarte TechSpot Ambassador Posts: 1,343   +6

    I would set the sub crossover slightly higher than the lowest frequency of the sats, but in actuallity, I'd play with it to see what sounds best to you.
     
  24. Nic

    Nic TechSpot Paladin Posts: 1,549

    Thanks for your kind comments olefarte. And you're right about subwoofers improving the sound in most systems, in fact I even have a small subwoofer for my dinky little mini-system at home.

    When I said that a sub wasn't necessary, this is only the case if you fit rather large 2-way units on the rear parcel shelf. Combined with the volume of air in the boot of the car, you can get some really deep bass that can shake your car. Really, subwoofers are like equalizers, you really only need one if the rest of your system isn't quite up to the task of producing deep bass.

    Be aware that if you are listening to music at a high volume in your car, with the windows up, then you should turn down the volume *before* opening any windows or doors, as the sound pressure level can increase dramaticaly and exceed the safety limit if you don't. There is a name for this effect, but I can't remember what it was, and you really can burst your eardrums if you are unlucky.

    As regards setting up your subwoofer, you'll have to use your ears. Just remember that you will want to allow only the lowest notes to reach the sub, so the lower the crossover is set the better. This also allows the bass to blend better with your other units so that bass sounds do not appear to be coming directly from the sub, but feel more non-directional. If you set your crossover too low then, you might experience less bass when certain instruments are played.

    Really a lot depends on how the speakers and sub work in your car, as certain parts of the frequency band will be accentuated by the locations of these units.

    Use your ears and experiment, its really the best way.
     
  25. olefarte

    olefarte TechSpot Ambassador Posts: 1,343   +6

    Nic, I totally agree again.

    Kind of off the actual subject, but I used to have a friend that had, I think it was, four 15", four 12 " woofers, two tweeters and two midrange speakers. Now that's a fine mix isn't it. He took out the back seat and had a whole trunk full of amps. Somehow he added an extra alternator and two extra batteries in the trunk, just to run all this stuff. He would wear earplugs and roll the windows down, and still had to silicone his windsheild and back glass every week to keep them from leaking when it rained. At night his headlights would dim in time with the music. Absolutly rediculous.
     
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