Main > Audio/Jukebox/MP3 Forum

Car Speakers with PC audio amp?

<< < (2/4) > >>

MaximRecoil:
Have you verified that the car speakers are functional? I assume that the Creative amp has been verified as working properly. You need to do some trouble shooting. There is no reason why a set of functional car speakers should not work with a functioning amp assuming that everything is hooked up properly. A speaker is a speaker. There is no difference in the functionality or application of a car speaker vs. a home speaker. You have a basket, motor (voice coil and magnet assembly), tinsel leads, cone and a surround.

Traditionally, home speakers have an 8 ohm impedance while car speakers have a 4 ohm impedance although this is hardly set in stone. Also, impedance really is not much of an issue although you don't really want to go lower than what the amp is rated for. Going higher (ie: 8 ohm speakers with a 4 ohm rated amp) is fine, although this will halve the power output of the amp. Music is dynamic anyway so the amp, while it may see a nominal impedance of 4 ohms when running 4 ohm speakers, will see actual impedances that jump all over the place.

In regards to the things that you have mentioned:

6 watts per channel going into car speakers rated for 35 watts RMS (root mean squared) = not a problem at all.

Impedance: Make certain that your amp is rated for 4 ohms (double check those original speakers to make sure that they are 4 ohm speakers). This would still not cause a buzzing sound, but running your amp at too low of a nominal impedance will shorten its life.

Use of a car amp: Not a very practical idea unless you have an inverter. Car amps want 12-14.4 volts and good quality inverters are expensive (the kind that they use in car audio shops for their display models). Plus, as I mentioned before, a speaker is a speaker. Car amps will power home speakers and home amps will power car speakers; it makes no difference (know what you are doing when it comes to impedance of course).

Polarity: Not much of an issue. Reversing the polarity on some speakers will cause them to sound different (some you will hear little to no difference, such as with a typical subwoofer) but it would not cause a buzzing noise.

My guess would be that you are getting some sort of interference from somewhere. Try moving cables and wires around. I have a set of PC speakers that will buzz if the wires get all jumbled with the other PC wires. Also, check for shorts and loose connections.

There is nothing inherently wrong with what you are doing with the car speakers to home amp thing. You just need to trouble shoot. Either something is broke or you are getting interference or whatever.



 

KevSteele:
Maxim,

I just did a speaker test, and wired the car speakers to my home stereo -- they sounded fine, and worked as expected.

Next, I verified the impedence of both the original PC speakers and the car speakers, and they're both at 4 ohms.

What I'm getting is just a gentle hum on the car speakers when the amp in the subwoofer is turned up to max. No hint of sound or music, even with the polarity reversed.

I'll do some more troubleshooting, but I'm still leaning towards the theory that there's just not enough power being sent to the speakers, or that the speakers are somehow overloading everything.

That said, I am an audio novice and I reserve the right to be completely, utterly, dumbfoundingly wrong.  :P

I might just buy a more powerful PC amp tomorrow and see if it solves the problem.

Kevin

MaximRecoil:
Very strange. If your amp really does put out 6 watts per channel, that is enough. That is about the same amount of power that a typical factory head unit in a car puts out. Even the "high powered" after-market head units only put out between 12-17 watts per channel RMS on average despite many of their lofty claims.

Just to be sure that I am following you; you can hook up the original speakers and they work fine, and then moments later hook up the car speakers and they only hum with no music or sound effects at all?

You are doing this with a 2.1 set of PC speakers? I have a 2.1 set of speakers on this PC and the amp is on the back of the subwoofer enclosure. There is a heavy cord coming out of the amp (connected to the amp with a round 10 pin plug) and it leads into the back of the right satellite speaker. Then the right satellite speaker has two smaller wires coming out of the back. One connects to the left speaker and the other connects to the sound card on the PC.

Now, if your speakers are set up like mine then there could be something that you missed when you took them apart and hooked up the car speakers. This is going to work differently than connecting a regular component amp (or home receiver) to a pair of speakers. My right speaker has a volume control and headphones jack. This means that there is a simple preamp in there. Does your PC speaker set have a preamp like that? Anyway, it seems kind of complex the way that PC speakers are wired and I have never taken a set of them apart. I would double check though to make sure that the only thing that you are changing is the speakers and that you are not missing anything. From what you said, you are attempting to adjust the volume from the knob on the sub's amp. If your speaker set is like mine, that will only adjust the subwoofer volume because the volume control for the channels of the amp that power the satellite speakers is up on the left satellite speaker itself. I'm just guessing here though because I don't know what you have for a speaker set and I don't know exactly how you have it rigged.

BTW, here is how you can prove to yourself that 6 watts is plenty to make sound through those car speakers. If you have a multimeter (or a volt meter) take and hook the car speakers up to the home stereo again. Start with the volume all the way down and the voltage across the speaker terminals should read 0 or maybe slightly above 0 if the volume isn't completely down. Then slowly turn your volume up until you reach 5 volts across the speaker terminals. That will be your 6 watts (6.25 watts actually) for a 4 ohm speaker. I promise you that by the time you reach 5 volts you will hear them fine. Watts = Voltage^2 / Impedance so in your case it will be 5v^2 which is 25 divided by your impedance of 4 which is 6.25 watts.

As a side benefit of doing that test you will also get to see just how little watts actually need to be fed to a speaker before you start to hear something. I have a feeling that your home stereo will start to make sound come out of those car speakers that you can hear faintly before you get to 1 volt (.25 watts for a 4 ohm speaker).

KevSteele:
Maxim,

Yup -- I can plug in the PC speakers into the PC Subwoofer, and it sounds fine, if I plug in the car speakers, nada.

Just to clarify a bit: the PC subwoofer has the amp unit inside, and on the back are two female RCA-style plugs. I've spliced some RCA male plugs onto the ends of the car speakers, and plug them into the subwoofer.

That's one of the reasons I first thought that the polarity might be an issue, so I re-wired one of the speakers, switching the connections at the speaker end. No improvement.

And yes, I can plug the PC speakers in and I get sound. Plug the car speakers in, and just a faint buzz.

I'll give the voltmeter a whirl today. This is too weird...

Kevin

SS427:
Use of a car amp: Not a very practical idea unless you have an inverter. Car amps want 12-14.4 volts and good quality inverters are expensive (the kind that they use in car audio shops for their display models).

You can also use a stand alone computer power supply instead of an inverter setup.  atx550w,,,20 bucks on ebay,,,,,,,,works great so far (amp and two 8" subs and two 4" speakers below the marquee)

ss

Navigation

[0] Message Index

[#] Next page

[*] Previous page