bass destortion

79zresto

Member
2007-12-24 9:41 pm
I am restoring a 79 z28 for my son. I have had the factory radio converted to a 4 channel digital pll system to preserve the factory apperance. When I hooked the system up the rear 6 x 9's are destorted. They are polk audio db691 4ohm 100w rms speakers. I hooked a set of speakers from his home stereo that say they are 6ohm and they sound fantastic with no destortion. Does anyone know a solution to my problem. Thanks
 
Wow, those are nice speakers. Maybe there is trash in the voice coils. Sometimes in rear deck speakers, trash can fall into the speakers and get lodged down in the voice coil. When the speaker is moving it will sound horrible. Sometimes you can remove the speaker and vacumm the trash out or turn them upside down while they are playing and let the trash fall out. Otherwise maybe someone blew them with an amp. Those speakers are too new to be worn out with normal use. Also check to see if one of the terminals at the speakers is touching the metal of the car and causing the radio to distort..
 

79zresto

Member
2007-12-24 9:41 pm
SPEAKERS ARE BRAND NEW, MAYBE A MONTH & HALF OLD.

I TRIED THE TRASH IDEA AND THERE WAS A LITTLE TRASH AND I BLEW IT OUT WITH AN AIRHOSE ON LOW PRESSURE AND I MAY GO TRY THAT AGIAN. I CAN'T FIND ANY WHERE THERE IS A GROUND PROBLEM. I HAVE EVEN REMOVED THE RADIO & SPEAKERS FROM THE CAR AND WIRED IT OUT OF THE CAR AND GET THE SAME SOUND.

I WIRED THE 6-OHM SPEAKERS WITH SAME WIRE AND THE SOUND IS REALLY GOOD. SYSTEM IS FOR 4 OHM SPEAKERS.

DOES ANYONE KNOW IF I COULD PUT A 2-OHM OR 4-OHM RESISTOR IN THE LINE TO EACH SPEAKER, IF THAT WOULD HAVE ANY EFFECT?
 
Connecting a resistor in series with the speakers will have an effect but it won't reduce the distortion if the speakers are damaged. The impedance of the load isn't the problem.

If there are no visible signs of damage and it doesn't sound like anything is scraping/scratching when you push in on the cone, the voice coils may have broken loose from the former.

Typing in all caps is annoying enough to some people to cause them not to respond to your thread.
 
Since you took the speakers out of the rear deck, why not bring them inside and connect to the stereo that you borrowed speakers from to test in car. The 6 ohm 4 ohm thing will not be a problem as long as you just connect them for a minute or so and do not turn them up loud. Just see if they have the same noise inside as they did in the car.
 
Are the 6x9's mounted in the rear deck? Did the prev owner have large subs in the trunk?

Rear deck? Trunk?...

Jeez, I saw 79zresto and was thinking 280Z, not Z28.

Well, the out of phase theory still holds anyway. Disregard any comments about little boxes or storage compartments.

Those cars were an absolute gift to car audio, as were the next generation. Any pair of 6x9's should deliver great bass in the rear deck.

Tim
 

jol50

Member
2007-11-08 2:14 am
Even better when you put 10s or 12s between the 6x9 and into the back seat.....:cool: Just plain amazing.

Check the speaker out good, see if the spider is loose from the former, see if the leads in there are hitting the cone or something, see if they make any noise or feel strange when you move them evenly and carefully by hand. Play them upside down for a while with some bass if they have dirt in them. They could be blown, but usually will rub inside.
 

79zresto

Member
2007-12-24 9:41 pm
I tried taking speakers inside and could not tell much difference.

Had already tried the phase thing and that was not the problem either.

I am the only owner the car has ever had. It was my first car and I had it ordered like i wanted it and have had the car since I was 17, so that makes me old, and I am now getting it ready for my son who is 16. The only thing that has been in the trunck was another set of 6x9's that were replaced with these.

Car had excellent sound before with factory stereo, Delco eqlizer and 60 watt amp. The cars were great for sound.

Thanks for everyone's input, but I finally took speakers to local audio shop and the plugged speakers into one of their systems and they sounded fine, so I purchased a new radio to put in the car. I think problem was in it all the time.

thanks