problem with subwoofer

G

Griffin.R

Audioholic Intern
I have a standard JBL subwoofer i recently decided to hookup to my amplified system, i already have a pioneer sub that performs well but wanted to try a second sub, yet after a few minutes of listening i noticed the jbl was making an odd noise. after further investigation and disassembly i realized it was the sound of the cone moving fast, this is a 4 ohm speaker and the rest of my system is 8 ohm and thats load i have set on amp, could this be the problem or is a problem with the cone itself, any fixes? thanks for any help. also forgot to add these are both ported yet the jbl is a smaller driver than the pioneer. and if it matters both are on a teak would peice, would carpet help?
 
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G

Griffin.R

Audioholic Intern
both powered by my yamaha m-80 natural sound power amplifier, output to bose 901 X2 and then both subs, its set at an 8 ohm load
 
G

Grador

Audioholic Field Marshall
If you have the subwoofers hooked up to the amp in parallel with the speakers then you're providing a dangerously low impedance to the amp.
 
fuzz092888

fuzz092888

Audioholic Warlord
If you're powering the subwoofers directly from the Yamaha amplifier, that would indicate that both subs are passive. In which case how are you implementing a crossover?
 
G

Griffin.R

Audioholic Intern
i am not implementing a crossover that i am aware of, the pioneer has frequency dial on back but the jbl does not. i dont know if this answers question as im not very familiar with crossovers and what not.
 
M

markw

Audioholic Overlord
What type of connections do these subs have? Speaker wires or an RCA jack?
 
G

Griffin.R

Audioholic Intern
both on speaker cables in the high level in, my old amp doesnt have a rca, lfe, or subwoofer specific output.
 
G

Grador

Audioholic Field Marshall
So are these both powered subs? [Do they plug into A/C]
 
fuzz092888

fuzz092888

Audioholic Warlord
It sounds like the JBL is powered by the Yamaha amplifier which would mean it's running full range with no crossover which could explain some weird noises coming from it.
 
G

Grador

Audioholic Field Marshall
It sounds like the JBL is powered by the Yamaha amplifier which would mean it's running full range with no crossover which could explain some weird noises coming from it.
But he mentioned using "high level" inputs as opposed to a possible RCA. I'm really confused at this point.
 
fuzz092888

fuzz092888

Audioholic Warlord
Could he have both connected to the Yamaha, using the terminals or binding posts on the JBL and the high level inputs on the pio?
 
M

markw

Audioholic Overlord
Perhaps I worded that unclearly. Are they powered subwoofers? That is, do they have built in amps and have to be plugged into the wall?
 
M

markw

Audioholic Overlord
wait a minute...

both powered by my yamaha m-80 natural sound power amplifier, output to bose 901 X2 and then both subs, its set at an 8 ohm load
Is there a Bose equalizer somewhere in there? The way you describe that signal path is bizarre, to say the least.
 
G

Griffin.R

Audioholic Intern
grador: yes both plug into a/c, sorry for possibly misleading
 
G

Griffin.R

Audioholic Intern
grador: both are plugged into a/c sorry if i replied wrongly
 
M

markw

Audioholic Overlord
Griff, you are extremely unclear in your writing. to be of any assistance, some facts need to be established.

You know, it's highly possible that JBL sub is toast. Let's explore that possibility. Answer these questions.

First off, Where is that Bose equalizer connected during all this? They add an ungodly amount of bass boost so it's possible it could overdrive the woofer. Take it out of the circuit for these tests.

First, disconnect both subs from the receiver.

Now, hook them up, one at a time to the receiver. Remember, disconnect the first sub when connecting the second one.

Do they both work? Do they both make that noise, or does only one make it?

If only one makes that noise, which one is it?

Now, if NEITHER made that noise, connect them both up in parallel.

If one again makes that noise, which one is it?

If the noise hasn't occured yet, reconnectthe Bose equalizer and tell us what happens.
 
G

Griffin.R

Audioholic Intern
ok ill start from beginning of questions for me, the bose eaqualizer is in there, i have a yamaha rx v371bl 5.1 ch receiver with all my inputs hooked up then the main audio out into the bose eaqualizer amp input (i know i can bypass the equalizer but i like use of bass and treble slides) then amp output into my yamaha m-80 power amp that outputs all through speaker cables (1 bose, jbl sub, in set a)(1 bose, pioneer sub, in set b) speakers on left subs on right outputs so the subs have same output theoretically. both subs are "powered subs" yet im not sure if they are both self amplified. any more questions? and thanks for replies
 
M

markw

Audioholic Overlord
OK, HERE'S a copy of your manual.

Why aren't you simply using the "sub out" jacks to feed the powered subwoofers instead of jerking around with this speaker level stuff??

Anyhow, I'm outta here. I'm not gonna fight to drag more information out of you.
 

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