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Dropping HU, Going Amp -- what are good reference websites?

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  • Dropping HU, Going Amp -- what are good reference websites?

    I'm not a car stereo "buff". I, like most others, know basic stuff -- don't connect the negative straight to the positive terminal of the battery, power doesn't come from nowhere, everything needs to be ground -- but I don't know squat about Amps. Despite being told multiple times, I still cannot grasp why stereos are rated as "4x40W" nor how that compares to a "100W Amp", if they can even compare at all.

    Anyway, I need an amplifier that takes two inputs, and makes.. uh.. an output. One input comes from the computer, the other comes from a Sirius receiver. I have 7 speakers somewhere in the car, I don't even know where to begin with that kind of wiring. Do I need 7-channel output? I sure hope not, I was hoping to take a nice and inexpensive 2-channel and replicate it, maybe step up to 4-ch to watch movies.

    Anyway, if someone knows the answer and has the time, I'd love to hear advice and replies. Otherwise, I don't mind learning -- but where do I go? What're good car audio review and forum websites?


  • #2
    I'll come back to this if nobody gets here first.


    • #3
      let me give it a whirl.


      You need a "recviever" or a signal splitter if you want both of your signals to be able to go into the amp.

      As for your amplifier, think about it this way: each "channel" output represents one distinct set of sound. you could, theoretically, split stereo sound into 7 speakers, say 3/4. That means 3 speakers would produce left channel sound and 4 would produce right channel sound. This is not optimal. You want your sound balanced. You could take a 4 channel amp (4 sets of sound, usually FR, FL, RR, RL) and split it into 7 speakers, or you could use a more advanced/expensive amp that has 5-7 channels and use that. It is up to you and what quality you want. Theoretically you could get a mono amp and have it run ALL the speakers (if it were rated with enogh power and the impedence matched up), but you would never want to.

      Asl for ratings, "40X4" means 40 watts on each of the 4 channels. a 100W rating doenst mean much unless we know how many channels, and at what impedence that rating is. To lean more about watts and ohms (impedence), check out . It is a great site and if you read on that everything in the section you are looking for (in your case amplifiers), and STILL have questions, i'm sure someone on this board will be able to help out

      Good luck, cherub, if i missed anything imortant, its all you.
      Cheap Laptop, great for Carputer!


      • #4
        Here's how my amplifier works:

                JVC Head Unit----|
                     |           |
                     |           |
             (4 RCA Connecters)  (Wire from antenna remote)-------|
                     |           |                                |
               4-Channel Amplifier-------------(2 RCA Connecters) |
               |     |     |     |               |                |
              Spkr  Spkr  Spkr  Spkr             |                |
                                               2 Channel Amplifier
                                               |                 |
                                            Subwoofer        Subwoofer
        The head unit is four channel and puts out 200 Watts. This means that each speaker will receive a maximum of 200/4 (that's 50) watts of power at the most. Once you put an amplifier on the speakers, this becomes entirely irrelevant. My 4 channel amplifier puts out 900 Watts at the most. This means that each speaker will receive 900/4 watts of power at the most. The amplifier will clean up the sound, so when you turn up the volume, every note is hit perfectly. The 4-Channel amp also has high pass enabled. This means that your speakers aren't going to try to thump. The 2-Channel has low pass, which means the subwoofers wont try to hit high notes. This will increase the time that the speakers and subwoofers last.

        I'm not too familiar with satillite radio, but it should have two RCAs that go out. You can plug this into the Line in on your computer, and let the computer handle it. Stop by Radio Shack and get an adapter that will go from the line out on your computer's sound card to RCAs that will connect to the amplifier. You'll also need a device to convert power from the accessory lead in your car to the 1 volt current that goes into the remote connecter on your amp. This tells the amp to turn on and off. After that just power and ground the amp, doesn't sound like its a problem for you.
        Audio Rockford Fosgate: 900 Watt 4-channel amp, 501bd Mono amp
        Computer AMD 2400+ XP, 1 GB DDR RAM, Orbit Micro 250W DC-DC PSU

        Head units are for cheaters!
        sure some girls fake orgasms.....but it's guys like me who fake the whole relationship