Alpine CDA-7832 and speaker impedance problem?

aydensdad · 06-27-2002, 09:38 AM

Hey all you car audio gurus... I have an Alpine CDA-7832 head unit, going through some amps and speakers/sub. But one thing I have not yet added to the system are front speakers. As I am on a budget, I'd like to just power the crappy stock speakers for now until I can afford another amp/speaker combo. So, I connect the front speakers to the HU, and I get crackly, distorted sound from the fronts that gets worse with more volume. The speakers are not marked, and I haven't had a chance to measure their impedance. Would this likely be the problem? Are my stock speakers probably rated at 8 ohms when my HU is expecting 4? Can I do anything to the circuit to lessen the impedance or make it work with the Alpine's internal amp? I lost my manual long ago, so I believe the Alpine is rated at 40watts (probably peak, and more like 20-25 rms). But I don't have any specs on what impedance those figures are for, and I can't find an online manual or datasheet. I'll try to contact Alpine... But can anyone help me figure out a hack to make the speakers work with a clean tone? Can I unwind the voice coils halfway to reduce impedance? Are there any simple circuits/components that I can wire into the line to make it work? Please let me know your ideas...

- Aaron

C4M · 06-27-2002, 10:01 AM

Quote:

Originally posted by aydensdad
Hey all you car audio gurus... I have an Alpine CDA-7832 head unit, going through some amps and speakers/sub. But one thing I have not yet added to the system are front speakers. As I am on a budget, I'd like to just power the crappy stock speakers for now until I can afford another amp/speaker combo. So, I connect the front speakers to the HU, and I get crackly, distorted sound from the fronts that gets worse with more volume. The speakers are not marked, and I haven't had a chance to measure their impedance. Would this likely be the problem? Are my stock speakers probably rated at 8 ohms when my HU is expecting 4? Can I do anything to the circuit to lessen the impedance or make it work with the Alpine's internal amp? - Aaron

Std speakers (aftermarket ones at least) present a 4 ohm load, and this is what your deck would be expecting.

If you're not planning a huge system, it's valid to run the fronts off the deck, and just use the amp to power any subs. This might allow you to upgrade the fronts now (fronts being the most important part of a sound system, cept your puter), and maybe go for the package deal later with the amp and the sub. Don't forget to get a crossover for the sub.

C!

aydensdad · 06-27-2002, 11:15 AM

Don't need a crossover, the head unit has a sub out. Anyways, my problem is that the sounds is very crackly and distorted from the stock fronts when run off the Alpine's power. I don't really understand why. The only thing that I can think of is that maybe the impedance isn't matched. Surely not EVERY stock speaker in EVERY car is 4 ohms? Or maybe they are... Who knows?

- Aaron

dazd&confuzd · 06-27-2002, 04:18 PM

It ain't the impedence. Every stock speaker I know of is 4ohms and even if it was 8, it would just have 1/2 the power. Doesn't effect SQ.
Only think I can suggest is take the deck out and recheck all the wires and connectors in the back. If everything looks good, run another set of wires for the speakers. If that still don't work, it's probably something wrong with the internal amp of the alpine.

Jason

C4M · 06-27-2002, 04:28 PM

Quote:

Originally posted by aydensdad
Surely not EVERY stock speaker in EVERY car is 4 ohms? Or maybe they are... Who knows?

Don't know about your stock speakers - but the 4 ohm number is pretty std for mots aftermarket car speakers.

C!