Subwoofer noise

 

New member
Username: Revo280

Post Number: 1
Registered: Feb-05
Just installed Polk PSW-303 to my sub-out jack on my receiver. It sounds great but when I was next to the sub to reposition, noticed constant, low "tin" vibration from sub; can also pick up some faint center channel noise (muffled sound of talking)..I can't hear these sounds sitting in my normal listening position. Is this normal characteristics of subwoofer? Any feedback would be greatly appreciated...A/V model below

Sony STR-DE945 A/V
(cross-over set to 90 all the way around, all speakers set to small)
 

Silver Member
Username: Usa2k4

Post Number: 109
Registered: Dec-04
It's quite normal to hear the lower part of the vocal from the subwoofer, especially when the low filter is set as high as 90Hz. The fundamental frequency of male voice can go down to about 85Hz or so, FYI. You can adjust the low filter on the receiver if it's adjustable and if your other speakers can reproduce bass lower than 90Hz. This will take care of the "problem".

The "tin" vibration part is a bit unusual. Are you sure it comes from the sub? Does increasing the volume also increase the vibration? Check for any loose wire inside the subwoofer's box if you don't mind opening it up. I hope the voice coil is OK.
 

New member
Username: Revo280

Post Number: 2
Registered: Feb-05
Thanks for reply. The cross-over can go from 60-180 in 30 step increments (ie 30,60,90, etc). Polk recommended I set crossover for front/channel at 80, though I can't do that. Would 60 be better than 90? My description of "tin" noise was bad. It sounds more like a very faint, muffled blown speaker (may be normal amp noise?) that can only be heard when right next to sub....
 

Silver Member
Username: Usa2k4

Post Number: 110
Registered: Dec-04
I'm not very sure about it. If increasing the volume doesn't increase the noise, it's OK.

Setting the cutoff frequency at 60Hz in most cases would be better than 90Hz as long as the lowest frequency that your speakers can reproduce can go down to about 55Hz or lower. But the manufacturer recommends a setting at 80Hz and this must be a reason, probably because the speakers that come with the sub can't go below 80Hz. In that case, you can connect the front left & right speakers to the sub and the sub to the receiver via the speaker-level in/out on the sub then set the front speakers to Large, the subwoofer to No and set the crossover control on the sub to 80Hz & the cutoff frequency on the receiver to 90Hz. This will work better in your situation.
 

New member
Username: Revo280

Post Number: 3
Registered: Feb-05
The sub has a volume knob and "low pass" knob with range from 60-160 (is this the x-over for sub?).
Also, if I set my front speakers to large, defaults to 120hz cross-over and can't be changed...but if I run thru sub like u suggest, should be fine, should be fine? Thanks for your time....It helps audio/HT newbs like me dial it in :-)
 

Silver Member
Username: Usa2k4

Post Number: 111
Registered: Dec-04
That low pass knob is the crossover control for the subwoofer.

Make sure you set the low pass knob on the sub to 80Hz. The frequencies at 120Hz and below from other channels (center, surround left & right, surround back's) will be routed to the 2 front left & right channels. Then the sound from 80Hz and below will be reproduced by the subwoofer and the sound above 80Hz will go to the 2 front speakers. The 80Hz cutoff will make your sub much less directional than the one at 90Hz and you'll hear much less "leaking" of the higher frequency sound from the subwoofer. If the sound from this setup doesn't please you, you can always go back to the initial setup that you mentioned above.
 

rabbitjoe
Unregistered guest
if i want to run two 12 inch sony xsl1290p5 what sort of powered amp would i need .cheers
 

rabbitjoe
Unregistered guest
if i want to run two 12 inch sony xsl1290p5 what sort of powered amp would i need .cheers
 

rabbitjoe
Unregistered guest
can some one answer that
 

Anonymous
 
Is there a way to find out what the cut off frequency of my speakers are? Bought the polk audio psw202 sub a week back and finally getting around to setting it up properly.

My speakers aren't the same spacing apart so the balance knob was slightly to the right side to fix this. Since I have gotten the sub and send the front channels through it then out to the receiver (set speakers to large and no sub) I have noticed that I have the turn the balance knob almost all the way to the right to get the proper balance.

I sent off an email to harman kardon, and they replied saying that since I have a digital receiver (avr 130) that the only way my sub should be hooked up is through the sub out rca type jack.
 

Silver Member
Username: Usa2k4

Post Number: 114
Registered: Dec-04
Try setting the balance knob at the center then use the test tone & speaker setup on the receiver to adjust the level of each speaker.

What's the make and model of your speakers? The subwoofer has a low pass filter adjustable from 80-160Hz which is to be used with the speaker-level input on the sub. If you connect the sub to the receiver via line-level input, this low pass filter is bypassed and you must use the receiver's low pass filter setting. It can be connected to the receiver by two ways, via the speaker in/out or via the line-in. However, depending on which way you connect it, you must adjust the low pass filter either on the sub or on the receiver accordingly. Since the line-level input on the PSW202 bypasses the sub's crossover, you need to use the receiver's low pass setting. The default low pass setting on the receiver is 100Hz for all speakers or you can manually set the cutoff point for each speaker. 100Hz is a bit high so if you can set the cutoff frequency to something lower than 100Hz and your other speakers can go that low, it would give better overall sound for your system.
 

Bronze Member
Username: Shokhead

Lakewood, CA USA

Post Number: 64
Registered: Jan-05
Set your speakers to small.
 

Nittany300!
Unregistered guest
From the sounds of it, I may have a similar problem ... but not sure.

The Sub on my Polk Audio RM6800 speaker system continually produces low-end vocals ... even when I've got the Yamaha rcvr turned off. Almost as if it is capturing some sort of broadcast signal out of thin air!

It's pretty faint, so not a problem when watching a DVD or DirectTV, but is kind of disturbing when the system is shut off and the room should be quite.

Appreciate any advice on this one!
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