Problem with Polk PSW650

BeefJerky

I just recently aqcuired a PSW650 sub to replace a Velodyne VX-10, because I wanted deeper bass as well as a bit more output. The PSW650 definitely does have deeper output, but there does seem to be an issue. It seems that the input on the sub is getting overloaded too easily, especially in the lower frequencies. Once the output from my receiver gets to a certain level, I hear the typical sound of an overloaded input coming from the sub. In addition, when it's doing that, if I adjust the volume on the sub itself, it won't bring it in or out of distortion, just increase or decrease the overall volume including the distortion. As such, I'm almost 100% sure it's the input to the sub itself that is getting overloaded. It seems that even with the sub volume set all the way up, the input overloads long before the amplifier would clip or the drivers would bottom out. I've tried both the LFE and the L/R RCA inputs and they both do the same thing. I tried putting my VX-10 back in, and it does not have the same problem.

My Setup:
Denon AVR-788
Fronts - Polk R50's
Center - Polk CSM
Surrounds - Polk T15
Sub - Polk PSW650

Thanks for any help or suggestions!

apphd

Not sure I follow you on this, but from what I read I would suggest you set the gain on the sub around 50% then go into the AVR and see what the sub volume is at it may be too high set it to 0 if that fixes the problem then add a little but I don't think I would go over +5dB. Also check to see if there is some type of a bass boost turned on in the AVR or your source. I see something called "EXT.IN Subwoofer level" in the Denon manual that says recommended +15dB. Try the +10 or +5 setting.

Two questions for you have you run the auto set up?
What do you have the master volume level at?

Maybe some Denon owners can give you more help.

Welcome to CP and good luck

BeefJerky

Sorry for the delay in replying, but I ended up pretty busy over the weekend.

On my receiver, the LFE level is set at 0, and there is no bass boost enabled. I'm currently running the receiver without Audyssey enabled, at least for testing purposes. I have also tested the speaker-level inputs and they react the same way.

For comparison,for a particular frequency my Velodyne VX-10's input will not be overloaded until the receiver is at -12, while the PSW650 will be overloaded at -32. That of course is a 20db difference in input to the sub, and it shows in the output. The PSW650, even with its volume set to max is *far* from the limits of the amplifier or driver excursion. As such, even the Velodyne with its single 10" driver can get louder. I know the PSW650 should be able to trounce the VX-10 if it was working correctly.

I took off the plate amp, and didn't see anything in particular that looked bad, but there definitely seems to be something wrong in the preamp section.

I have submitted a request to Polk to see if the plate amp is available at a reasonable cost. I'm wondering whether I should just cut my losses and get a new sub at this point.

Thanks for any advice!