Larry B.

whenever I post on the electronic section I get ignored so I'll just ask here. I have put the original Deco radio back in and have a quick question I have a medium priced set of pioneer 4X6in the kick panels (no dash speakrs in 69) and a set of 8" optimus speakers in a teardrop shaped enclsure stuffed into the rear corners.(almost unseen) I wired each side in series to achieve the 8 ohm requirement for the delco radio. Here's my question I have a few bass frequencies that tend to "boom" or be louder. The overall sound is real good but I would like to fix the "boom" I realize that the optimus speakers aren't the best but they fit excellent. I'll get rid of them if I have. Any idea's??

77Dream

They may be under-powered, you might try getting a small amp to boost the power too them. 40-50 watts each should be good.

waddell64

:iagree:

Adam

Crickett

:iagree:

bigvette1

Yep the AC Delco radios were about 5-8 watts without the amp and then only about 10 watts RMS per channel. Get a separate amp for the rears that has both the RCA inputs and the inputs for radio output. The AC Delco's did not have the low impedance O/P or line out with the RCA jacks. You may also need an isolation transformer if your speakers in the rear are picking up a lot of junk via the amp. They have them at Radio Shack. Good luck.

Larry B.

I don't get it! What does the low power have to do with just certain frequencies resonating? How would an amp fix that? I am just trying to have a decent sounding radio. Right now it sound very good with the tone control set mid point. Just a couple of bass notes seem to resonate from time to time. :confused:

mrvette

Blue, you are correct in your note above, the amps have nothing to do with it....what you need is an andustable notch filter, and that gets complicated for the typical user....not such a big deal for me, but I have unfair advantage....

it first needs be identified as to exactly what freq is the most offensive, and maybe even a second frequency....and some filters built to put in the input line of the amp, and adjusted around untill the offending loud resonating notes are gone....

McIntosh is one of the very few real stereo companies doing that stuff, for the real home stereos anyway, I"m sure they have something similar for a car too, but I don't in fact know....

what that filter is made of.....quad op amp chip....and about a dozen resisitors, and maybe a dozen capacitors....plus two or four potentiomaters...(volume controls).....

GENE

dman535

The resonance that you are hearing might be the speakers distorting due to lack of power. You may be hitting frequencies that the speakers can reporduce, but there is not enough control of a voice coil to reproduce those sounds. The Delce radios really lack power, if you are dirivng four speakers with a standard delco head unit I am surprised the think had not melted yet. A 50w-75w amp will do wonders for your system.

Larry B.

I wired two 4ohm speakers in series per side. The radio requires 8-10 ohm speakers so I have met that requirement. If I wired them in parallel then It would have been 2 ohms... That WILL cook the unit.

77Dream

Like I said above... you need an amp. Not a very big or expensive one, you could prolly get one for 30 - 50 bucks. Too much amps and the speakers distort then blow, too little amps and they just distort and sound like s**t. How much is too much or too little? That just depends on the speakers. But generally about 40 amps to each one should be in their range.

As for the ohm's, if the speakers are rated wrong then get new ones (speakers are cheap). But from my experience you dont really have to worry about the ohm's that much, I would just hook them up normally. Isn't ohm's just a measure of resistance anyway? How would having less resistance cook the unit? If you hook them up parallel you should be fine. I have never heard a system that sounded good that had speakers wired in a series, except for some complex subwoofer boxes that are powerd by some big amps.

:cheers:

Larry B.

That's a hard concept to explain but if you keep adding speakers in parallel, the amp will overheat... kinda like running an engine wide open in neutral.. It will blow up. V=IR .... ohms law is universal.