PSW-50 sub replacement driver question

mmcelarn

Hi,
I'm about to replace the driver on my psw50 sub. I'm not sure if it's the driver or the amp, so I'm going the path of least cost first!
I called Polk's 1800 number and talked to a nice lady. She told me that the MW8004 driver that came with the sub is no longer available an that the MW8003 is the replacement. She directed me to Club Polk to further my cause.
What do I do now? Should I locate a local dealer or can I order the driver through the polk website?

Thanks in advance, M

gatemplin

mmcelarn wrote:

Hi,
I'm about to replace the driver on my psw50 sub. I'm not sure if it's the driver or the amp, so I'm going the path of least cost first!
I called Polk's 1800 number and talked to a nice lady. She told me that the MW8004 driver that came with the sub is no longer available an that the MW8003 is the replacement. She directed me to Club Polk to further my cause.
What do I do now? Should I locate a local dealer or can I order the driver through the polk website?

Thanks in advance, M

Pull the driver, hook up a multimeter to the terminals and measure the resistance. You should measure something like 3 to 7 ohms. If it measures open or 0 ohms replace the driver, otherwise look for other problems.

mmcelarn

Now you're scaring me!
I measured the impedence a few days ago and got 3.7ohms. While I had the box open, I looked around for burnt components and obvious faults with the amp - couldnt find any! I assumed that the driver was blown because of the rattley distortion / artifacts in the sound. Just because the driver is offering 4ohms resistance doesnt mean it's responding correctly, right?
What do you recommend now? I guess I can try to talk a friend into allowing me to plug my driver into his sub with respect to the specs.
M

gatemplin

mmcelarn wrote:

Now you're scaring me!
I measured the impedence a few days ago and got 3.7ohms. While I had the box open, I looked around for burnt components and obvious faults with the amp - couldnt find any! I assumed that the driver was blown because of the rattley distortion / artifacts in the sound. Just because the driver is offering 4ohms resistance doesnt mean it's responding correctly, right?
What do you recommend now? I guess I can try to talk a friend into allowing me to plug my driver into his sub with respect to the specs.
M

You can try gently pushing on the driver. If it moves smoothly, and the resistance is in about that range, and the voice coil former isn't seperated from the diaphragm or some other obvious mechanical problem, then the problem is likely elsewhere. Probably the amp.

mantis

I got a psw50, it works great. It's in good condition.

Talk to me,

Dmantis20@aol.com

Or PM me here.

Dan

mmcelarn

well gatemplin, from the few simple tests you're recommended, it appears that the driver is ok. This isnt what I wanted to hear. I'd still like to bring the sub around to a friends house so we can swap drivers to make sure which component is faulty.
I'll keep you posted!

M

gatemplin

Try that to be sure. You can get cheap plate amps from www.partsexpress.com . If you need a new amp, you might as well just build a whole new sub.

mmcelarn

I've read up on speakers in general, I'm not too 'religious' on the topic, but a lot of people say that you absolutely must get the right driver / amp / enclosure combination or you loose a lot of the fidelity because of some sound phenomena. So what I"m asking is - could I get a Dayton sub amp and plug stick it into the polk enclosure without much detriment?

M

jarros

mmcelarn wrote:

I assumed that the driver was blown because of the rattley distortion / artifacts in the sound.

It might be the enclosure that's making the noise. If that's the case, your driver and amp would both be OK. If it is the enclosure, it can be tough to locate and cure the noise.

One way you could check to see if it's the enclosure is to take the sub out of the box but still leave the leads connected. Play some frequency sweeps in the subwoofer's range (I dunno, 30-150Hz?) and see if it makes noise. Be careful about volume though, you don't want it bottoming out. If you still get noise, that means it's either the driver or the amp. If you can swap drivers with a friend, conduct the same tests to see if you can narrow down the problem.

If you find that it is your amp, yes, you can replace it with another one, like a dayton. An amp/driver/enclosure combination isn't crucial, but the driver/enclosure part is. If you're replacing the amp with one that has the same power ratings, I wouldn't worry about it. The problem with that is the amp will be a different size, so you'll have to cut a new hole for the amp, or just build a new enclosure

mmcelarn

So I didnt get to test out the driver on my friends' subs - none of them would let me near their system! A friend in need, huh?

Ok, so the driver arrived in the mail today, I plugged it in right away and ran a few test tones. It seems that it's better but not perfect. The sub is playing music fine and it's listenable, but when I run the test tone, it starts off at 40Hz, and it sounds bad. If you can imagine pursing your lips and blowing like kids do to emulate the sound of a airplane engine - that's what it's like. Depends on the volume too. Above 100Hz it's perfect. Unfortunately, I've no way of telling what frequency it starts to break up and if that's within the specs of the sub - the specs aren't published.
Maybe it was like this when it was new, I didnt listen with such a critical ear back then - I was just glad to hear the boom!
So it'll do for the moment, I might get an external amp some time in the future! Thanks for all the support, I learned quite a lot here, I didnt know speakers were so complex.

M

jarros

It really sounds like it could be the enclosure that's at fault. Did you get a chance to test the driver hooked up to the amp when the speaker wasn't in the enclosure?

If it is the enclosure, you might be able to solve the problem by applying wood glue in all the corners on the inside of the cabinet. It shouldn't take long to do, and in my opinion it's worth spending an hour or so to do it rather than having to live with the noise. Trust me, now that you know it's there you'll have a very hard time getting your mind off it while listening to music or watching movies.