PSW 650 -11db roll-off at 35Hz

haghighi

Just had my system calibrated by a THX technician, looks like the PSW 650 begins rolling off at 35hz and continues to fall drastically. I am assuming this is the expected behavior. I was a bit dissapointed to hear that the Polk performed poorly compared to many of the others he had calibrated and measured. I realize that room dynamics have quite a lot to do with it, but I believe he calibrated to compensate for the cancellation factors.

Just curious what others have experienced. It seems that I am not getting the low end movie track rumbling on tracks like U571, etc....

As an alternative, the engineer recalibrated the fronts set to large, and it does sound better, but I am a bit worried about performance overall with soundtracks with plenty of LFE info.


Any thoughts or ideas would be appreciated...

fireshoes

While current Polk subs are not much for playing subsonic, I would have to think you have a major room problem to be -11 at 35hz.

jakelm

As a Polk fan, I would have to honestly agree that, thats a typical Polk sub for ya.

fireshoes

-11 at 35hz is not typical of the PSW650 though. We're not talking the PSW10 or 202 here. It's -3db rating is 28hz.

jakelm

I thought he ment it starts a 11db roll off @ 35hz. In which most of Polk's sub's subsonic 12db filter start at 30hz.

jakelm

fireshoes wrote:

It's -3db rating is 28hz.

Then there is about a 12db dro every octive after 28hz. So that and being in a slight null will cancell just about everything under 30hz.

haghighi

The drop is as follows:
-35@35Hz
-45@30Hz
-50@28Hz
-57@25Hz

Room has been eq'd for standing wave and reverb. I was told that speaker placement would not change the subs performance. So what gives?

Calibrator recommended I look at B&W's subs which he says consistenly flat lined down to 20Hz.

What am I really missing from 35Hz to 20Hz? I get a sense the rumbles aren't there for movie soundtracks, but it's okay for most music...

jakelm

haghighi wrote:

I was told that speaker placement would not change the subs performance. So what gives?

.

BOOOOMP....Wrong.. It doesnt matter how well the sub performs...placement WILL effect the performance of a sub in ANY room.

fireshoes

haghighi wrote:

The drop is as follows:
-35@35Hz
-45@30Hz
-50@28Hz
-57@25Hz

Room has been eq'd for standing wave and reverb. I was told that speaker placement would not change the subs performance. So what gives?

Calibrator recommended I look at B&W's subs which he says consistenly flat lined down to 20Hz.

What am I really missing from 35Hz to 20Hz? I get a sense the rumbles aren't there for movie soundtracks, but it's okay for most music...

I seriously hope whoever it was doing the calibration didn't tell you that about placement not affecting performance.

As far the numbers you've given there, is that the amount down from the peak? It's hard to really put that in relation to overall performance if it is, because you could have a pretty big peak in there. We need to figure out how it relates to the average. I'd suggest getting an SPL meter and taking your own measurements and plotting out the readings. Try several different placements for the sub and try to find the flattest response. Your sub is capable of much better than what you are getting.

VR3

sounds like your installer is a B&W fan.

While the Polk isnt a hardcoe sub it should dig to 25hz with room gain.

RuSsMaN

The 650 is a GREAT sub, with a ton of accolades. It is ever bit a hardcore sub, and then some.

fireshoes

I'm going old school Club Polk here; I'm trying to find rat shack spl corrections and bass test tones for download.

Radio Shack analog SPL meter corrections:
http://www.polkaudio.com/forums/showpost.php?p=181692&postcount=52

jakelm

fireshoes wrote:

I'm going old school Club Polk here; I'm trying to find rat shack spl corrections and bass test tones for download.

Radio Shack analog SPL meter corrections:
http://www.polkaudio.com/forums/showpost.php?p=181692&postcount=52

Old school always worked for me....:D

haghighi

jakelm wrote:

BOOOOMP....Wrong.. It doesnt matter how well the sub performs...placement WILL effect the performance of a sub in ANY room.

He said moving my sub would not make a difference, not that it doesn't. Given my room dynamics, it was already in the optimal place.

jakelm

haghighi wrote:

He said moving my sub would not make a difference, not that it doesn't. Given my room dynamics, it was already in the optimal place.

I understand now..


If you want to get really "old school". Put the sub where you sit and crawl around the room along the walls , untill you hear the best output....then place the sub where you ended up.

I would download sine waves and play the 30hz - 40hz track (on repeat) while crawling around the room.

haghighi

Vr3MxStyler2k3 wrote:

sounds like your installer is a B&W fan.

While the Polk isnt a hardcoe sub it should dig to 25hz with room gain.

He doesn't own a b&w himself, he was just presenting what he's experienced by the numerous calibrations he's done. Basically he thought the b&w was the most consistent performer down to 20Hz, I don't see why he would mislead me if this is historical data he's collected over time.

haghighi

fireshoes wrote:

I'm going old school Club Polk here; I'm trying to find rat shack spl corrections and bass test tones for download.

Radio Shack analog SPL meter corrections:
http://www.polkaudio.com/forums/showpost.php?p=181692&postcount=52

I have the Digital SPL, this calibrator also had a hand held meter that displayed the specturm range as well as the dB, anyone know where to get something like that, it was really cool, probably like $500 or so...when he ran to through the test tones he was using a $600 mic rig +/- .5db accuracy hooked up to his laptop. Makes me feel so inadequate with my rat shack spl
But hey it does the job, even if I can't see the db's for each frequency

LuckyTage

haghighi wrote:

Just had my system calibrated by a THX technician, looks like the PSW 650 begins rolling off at 35hz and continues to fall drastically. I am assuming this is the expected behavior. I was a bit dissapointed to hear that the Polk performed poorly compared to many of the others he had calibrated and measured. I realize that room dynamics have quite a lot to do with it, but I believe he calibrated to compensate for the cancellation factors.

Just curious what others have experienced. It seems that I am not getting the low end movie track rumbling on tracks like U571, etc....

As an alternative, the engineer recalibrated the fronts set to large, and it does sound better, but I am a bit worried about performance overall with soundtracks with plenty of LFE info.


Any thoughts or ideas would be appreciated...

What A/V Receiver are you using? I found this---> http://www.audioholics.com/education/frequently-asked-questions/handling-various-bass-management-dilemmas

Systems

jakelm wrote: »

...placement WILL effect the performance of a sub in ANY room.

It sure Will.

haghighi,If you place the sub in a corner (if not already)you will get some boundry reinforcement which will increase the output below 35hz.

surfntomm

i have 2 psw650's and if you are not getting rumble in movies such as u571 or LOTR trilogy then either your sub is whack and not working correctly or your room is so big that your sub does not match the kind of money that you could be spending on it with such a huge house. the psw650 sounds very solid at 35 hz and even 30 hz. if you have a laptop download something called a test tone generator and it will play any frequency you want and it can do a sweep too. go to www.download.com and type in test tone generator, you shouldnt have to pay someone to tell you how low your sub can go (only takes 2 min)

LuckyTage

Has anyone ever replaced the subwoofer inside the PSW650 for a newer 10' subs? And if so how does it sound?

haghighi

surfntomm wrote: »

i have 2 psw650's and if you are not getting rumble in movies such as u571 or LOTR trilogy then either your sub is whack and not working correctly or your room is so big that your sub does not match the kind of money that you could be spending on it with such a huge house. the psw650 sounds very solid at 35 hz and even 30 hz. if you have a laptop download something called a test tone generator and it will play any frequency you want and it can do a sweep too. go to www.download.com and type in test tone generator, you shouldnt have to pay someone to tell you how low your sub can go (only takes 2 min)

I have numerous calibration discs. I've tried them all at 30Hz there is barely a peep, at 40Hz I start to hear the rumble. Sub is placed in a corner. Receiver crossover is set to 80Hz (THX) speakers are set to small, everything should pretty much be correct here.

I just don't think this sub is pulling it's weight for it's size and drivers...

RuSsMaN

Quit saying THX this, THX that.

Try a different placement, and some of the options posted above. Room dynamics, reverb? Your 'tech' seems to have a lot of big words in his audio pocket, yet no real advice.

Listen to the polkies here. Placement, phase, and proper calibration and you should be loving life with a 650.

Cheers,
Russ

rskarvan

I've never loved my PSW 650. I've tried... but, I just don't love it.
The sub is in a corner and it just isn't loud enough.
If I turn the volume on the sub all the way up, it distorts.
If I switch the toggle for the +3 db gain, it distorts.

It works... it makes sound... both drivers thump... but, its been a major disappointment. I would love to have a "shake the house" sub... but, 650 just doesn't have much in the way of GET YOUR ATTENTION THUMP.

My only Polk disappointment is the PSW650.

On a positive note though, I do like that it turns itself on and off flawlessly when a signal is sensed. That is cool.

jakelm

haghighi wrote: »

I have numerous calibration discs. I've tried them all at 30Hz there is barely a peep, at 40Hz I start to hear the rumble. Sub is placed in a corner. Receiver crossover is set to 80Hz (THX) speakers are set to small, everything should pretty much be correct here.

I just don't think this sub is pulling it's weight for it's size and drivers...

Is the sub driver moving at lower the 30hz or does the vibration get less and less? As the FR gets lower the driver should physically want to jump out of the box. If so, move the sub around. If not , the Hp crossover (rumble filter) is set too high.

On both of my subs, as the Fr get lower the excursion is unbelievable and the subs want to jump out of the box. But if I am sitting in the wrong posistion , I cant hear a damn thing. But I can see the sub driver, working and driving.

haghighi

jakelm wrote: »

Is the sub driver moving at lower the 30hz or does the vibration get less and less? As the FR gets lower the driver should physically want to jump out of the box. If so, move the sub around. If not , the Hp crossover (rumble filter) is set too high.

On both of my subs, as the Fr get lower the excursion is unbelievable and the subs want to jump out of the box. But if I am sitting in the wrong posistion , I cant hear a damn thing. But I can see the sub driver, working and driving.

No movement at 30hz or below. I spent time last night changing crossover settings and speaker sizes using frequeny sweeps, anything below 35hz is not there.


One thought I have is to use the Front Speakers R&L on the receivers AMPs since I am just using it as a pre/pro have it set the Fronts set to Large and disable the LFE channel....

jakelm

Looks like whats going on is, the AVR is treating your sub like a main or surround speaker. Set the AVR to treat the mains as large, the hook the preout left or right (or both) from the AVR to the sub.

All in all there is some filter in the signal path that is high pass crossing over below 35-40hz, as if the sub was a "small" speaker.

My HK635 has a built in rumble filter that I can adjust by adjusting the size of the sub. If I set the sub to 8" the rumble filter from the HK starts its slope at 30hz, 10" sloped at 25hz, 12" @ 20hz, 15" @ 15-18hz.

I leave the setting @ 15" and use the Rythmik's rumble filter to control the Hp crossover.

You could try hooking the DVD player directly to the sub. And run your test disk. That might work, but put the sub volume very low then increase.

haghighi

jakelm wrote: »

Looks like whats going on is, the AVR is treating your sub like a main or surround speaker. Set the AVR to treat the mains as large, the hook the preout left or right (or both) from the AVR to the sub.

All in all there is some filter in the signal path that is high pass crossing over below 35-40hz, as if the sub was a "small" speaker.

My HK635 has a built in rumble filter that I can adjust by adjusting the size of the sub. If I set the sub to 8" the rumble filter from the HK starts its slope at 30hz, 10" sloped at 25hz, 12" @ 20hz, 15" @ 15-18hz.

I leave the setting @ 15" and use the Rythmik's rumble filter to control the Hp crossover.

You could try hooking the DVD player directly to the sub. And run your test disk. That might work, but put the sub volume very low then increase.

Not sure how that can happen since I am using the LFE output on the AVR, that would indicate it's not working as it should. Setting the Mains to small or large has no effect, crossover is set at 80hz, a sweep doesn't show a gap or drop from 40Hz up, smooth transition to mains, anything under is 0.

I am using the AVR as a pre/pro so I don't have the pre outs available. I will see if there is a sub sizer option in Pioneer Elite 84...

jakelm

Just recheck all connections .

haghighi

No luck, still have issues. I think I am going to dump this sub for one that can doesn't has such a roll off like this.

haghighi

Just looked up the specs:
Overall Frequency Response 25Hz - 180Hz
Lower -3dB Limit 28Hz
Upper -3dB Limit 125Hz
Crossover
(subwoofer) 60Hz - 160Hz, adjustable Low Pass Filter. Selectable 80Hz High Pass Filter on the line level outputs.
Inputs speaker, line, LFE (unfiltered)
Outputs speaker and line level with optional 80Hz high pass filters

---

Polk reports a 25Hz floor, yet I am getting significant roll off at 40Hz!? What gives.