PSW350 Placement/Phase Assistance...

[PearlcorderS701]

I am running a rather "vintage" Polk PSW350 in my system, and while it has serviced me thus far through a few different systems, I recently re-installed it in a new system when we bought our new house less than a month ago.

Not really happy with the slam I have been experiencing since putting the sub in the new room, I spent a good deal of time today experimenting with placing it in a corner and adjusting the phase control; what I discovered was that placing it in the corner, with the port actually firing into the corner itself (so the sub is catty-cornered when looking at it) may have perhaps made the effect more "loose" and "sloppy" which was expected, but I can't really tell if it improved output or overall tactile slam at all. So, I switched the position back to where it was, directly to the left of the left front main (a Polk RTi12 tower) and ran various sequences off the Haunting (1999) DVD which contains a great deal of ultra low sub bass on the DTS-ES soundtrack and did back-to-back comparisons. I couldn't really tell if one position sounded "better" than the other; from what I can hear, the position against the wall next to the left main channel may have made the bass a bit "tighter" and "more controlled," but with a bit less slam...

Now, with regard to phase, I was advised to leave this switch on "0" degrees (my PSW350 has a toggle for 0 or 180) and to keep the Low Pass Filter of the sub on its HIGHEST position because there is no bypass mode on it. On the 350, this level is "160Hz". While that seems a bit high to me, I jacked that up all the way. I experimented with switching the phase between 0 and 180, but honestly, I cannot tell if there's a difference...is this normal, for the phase not to make an audible difference in most cases? What should I keep it on then? The rear of the sub has the 180 degree position "suggested" by Polk with a white box indicator; is 180 or 0 correct?

For reference, I am running my Onkyo receiver's LFE OUT direct with a single gold plated Monster RCA sub cable to the Polk sub's LFE UNFILTERED IN and keeping all crossovers in the receiver to 80Hz (main, center, surrounds); should this Low Pass knob on the sub make any difference where it's set? As far as placement, if I can't really detect a difference between the corner or the wall next to the left main speaker, should I just leave it where it is, along the main wall next to the left channel? Would it be better not to leave it in the corner because of too much roll off and "boominess"?

 

[TLS Guy]

I am running a rather "vintage" Polk PSW350 in my system, and while it has serviced me thus far through a few different systems, I recently re-installed it in a new system when we bought our new house less than a month ago.

Not really happy with the slam I have been experiencing since putting the sub in the new room, I spent a good deal of time today experimenting with placing it in a corner and adjusting the phase control; what I discovered was that placing it in the corner, with the port actually firing into the corner itself (so the sub is catty-cornered when looking at it) may have perhaps made the effect more "loose" and "sloppy" which was expected, but I can't really tell if it improved output or overall tactile slam at all. So, I switched the position back to where it was, directly to the left of the left front main (a Polk RTi12 tower) and ran various sequences off the Haunting (1999) DVD which contains a great deal of ultra low sub bass on the DTS-ES soundtrack and did back-to-back comparisons. I couldn't really tell if one position sounded "better" than the other; from what I can hear, the position against the wall next to the left main channel may have made the bass a bit "tighter" and "more controlled," but with a bit less slam...

Now, with regard to phase, I was advised to leave this switch on "0" degrees (my PSW350 has a toggle for 0 or 180) and to keep the Low Pass Filter of the sub on its HIGHEST position because there is no bypass mode on it. On the 350, this level is "160Hz". While that seems a bit high to me, I jacked that up all the way. I experimented with switching the phase between 0 and 180, but honestly, I cannot tell if there's a difference...is this normal, for the phase not to make an audible difference in most cases? What should I keep it on then? The rear of the sub has the 180 degree position "suggested" by Polk with a white box indicator; is 180 or 0 correct?

For reference, I am running my Onkyo receiver's LFE OUT direct with a single gold plated Monster RCA sub cable to the Polk sub's LFE UNFILTERED IN and keeping all crossovers in the receiver to 80Hz (main, center, surrounds); should this Low Pass knob on the sub make any difference where it's set? As far as placement, if I can't really detect a difference between the corner or the wall next to the left main speaker, should I just leave it where it is, along the main wall next to the left channel? Would it be better not to leave it in the corner because of too much roll off and "boominess"?

Your first problem is that you have the sub that isn't. That unit is not a sub, and only fits the definition of a bass module. It is 3db down at 38 Hz and then rolls off 24 db per octave. That is well above sub range. That unit does not even have the bass output of my center channel, and a lot less than my rear surrounds! To be a sub it needs to have an F3 point somewhere south of 30 Hz.

Now your mains have an F3 point of 30 Hz. So your mains can play lower than your sub.

So if the Polk specs of your tower are honest, you will get more bass without your sub. So try setting your speaker set up to sub, none.

If you don't like that, the the next thing to try is to set your mains to large and the low pass receiver crossover to 60 Hz and gradually set your bass module volume to where it gives a slight lift to your mains. However you need to set your mains to large for sure with that set up, as they will be producing most of the bass and the lowest frequencies.

As to your other points in the corner it likely loaded frequencies between 50 and 60 Hz and made it boomy.

As to phase, a phase control needs to be continuously variable between 0 and 180 degrees.

It is impossible to guess all the phase shifts of amps and speakers in the chain. If it so happens that the sub is close to in phase or 180 degrees out of phase with the mains, then either 0 or 180 degrees will have a higher output. However if the phase shift is around 45 degrees then the setting of a switch like yours will make no difference.

So if is deep slam you want you need a new sub, and one of much better quality and performance. I would look at the offerings of HSU and SVS for a start.

 

[AVRat]

http://forums.audioholics.com/forums/showthread.php?t=63756
http://forums.audioholics.com/forums/showthread.php?t=63754

 

[PearlcorderS701]

http://forums.audioholics.com/forums/showthread.php?t=63756
http://forums.audioholics.com/forums/showthread.php?t=63754

You know something, Rat? It slipped my mind that I had posted those before...thanks...

 

[PearlcorderS701]

Your first problem is that you have the sub that isn't. That unit is not a sub, and only fits the definition of a bass module. It is 3db down at 38 Hz and then rolls off 24 db per octave. That is well above sub range.

Perhaps on paper, but I refuse to believe that the 350 is that bad...

That unit does not even have the bass output of my center channel, and a lot less than my rear surrounds! To be a sub it needs to have an F3 point somewhere south of 30 Hz.

That may be by some stretch, but to be honest, looking at your seriousness of your involvement in this "hobby" through pictures you provide, the average HT enthusiast isn't anywhere near where you are -- I mean, how many of us have centers and surrounds that actually play lower than a sub...even one as "weak" as a PSW350??

Now your mains have an F3 point of 30 Hz. So your mains can play lower than your sub.

So if the Polk specs of your tower are honest, you will get more bass without your sub. So try setting your speaker set up to sub, none.

If you don't like that, the the next thing to try is to set your mains to large and the low pass receiver crossover to 60 Hz and gradually set your bass module volume to where it gives a slight lift to your mains. However you need to set your mains to large for sure with that set up, as they will be producing most of the bass and the lowest frequencies.

This is an entirely different issue, and one that I needed to get more input on -- I realize the RTi12's can play seriously low for a somewhat slender tower, but I don't want to run them on full range because I don't want to tax my Onkyo 605 more than it is already. I need to integrate a sub into this situation somehow, and the PSW350 is what I am working with at the moment, regardless of whether it's really "the sub that isn't."

Given that, I have the RTi12 mains crossed over at 80Hz inside the AVR...can you give me a crossover recommendation for these where some of their bass would be used, at least, to integrate decently well with the PSW350, without having to set them to Full Range? Should I be using another crossover point other than 80Hz?

As to your other points in the corner it likely loaded frequencies between 50 and 60 Hz and made it boomy.

Should I just keep it out of the corner and leave it along the main wall, directly to the left of the left main RTi12 tower?

As to phase, a phase control needs to be continuously variable between 0 and 180 degrees.

It is impossible to guess all the phase shifts of amps and speakers in the chain. If it so happens that the sub is close to in phase or 180 degrees out of phase with the mains, then either 0 or 180 degrees will have a higher output. However if the phase shift is around 45 degrees then the setting of a switch like yours will make no difference.

I just don't hear a difference, after hours of testing this...unless I am wrong. What should I keep the phase switch to then? Why did Polk provide a "white box" indicator outlining that 180 should be the recommended position?

So if is deep slam you want you need a new sub, and one of much better quality and performance. I would look at the offerings of HSU and SVS for a start.

Yes, I indeed have HSU and SVS on my list of must-demo subs; and that will be one of the next upgrades. I realize this and my AVR are the weak links in the system right now.

 

[TLS Guy]

Perhaps on paper, but I refuse to believe that the 350 is that bad...



That may be by some stretch, but to be honest, looking at your seriousness of your involvement in this "hobby" through pictures you provide, the average HT enthusiast isn't anywhere near where you are -- I mean, how many of us have centers and surrounds that actually play lower than a sub...even one as "weak" as a PSW350??



This is an entirely different issue, and one that I needed to get more input on -- I realize the RTi12's can play seriously low for a somewhat slender tower, but I don't want to run them on full range because I don't want to tax my Onkyo 605 more than it is already. I need to integrate a sub into this situation somehow, and the PSW350 is what I am working with at the moment, regardless of whether it's really "the sub that isn't."

Given that, I have the RTi12 mains crossed over at 80Hz inside the AVR...can you give me a crossover recommendation for these where some of their bass would be used, at least, to integrate decently well with the PSW350, without having to set them to Full Range? Should I be using another crossover point other than 80Hz?



Should I just keep it out of the corner and leave it along the main wall, directly to the left of the left main RTi12 tower?



I just don't hear a difference, after hours of testing this...unless I am wrong. What should I keep the phase switch to then? Why did Polk provide a "white box" indicator outlining that 180 should be the recommended position?



Yes, I indeed have HSU and SVS on my list of must-demo subs; and that will be one of the next upgrades. I realize this and my AVR are the weak links in the system right now.

If the specs from Polk say your sub is 3 db down at 38 Hz, it certainly will not be better than that. So paper or not that is the way it is. Your unit can not reproduce the last musical octave no matter what you want to believe.

So I think you are optimal now. I have no suggestions, for improvement other than trying different locations.

A lot of your difficulties are due to lack of knowledge on your part of common terms and grasp of basic essential details.

There is a limit as to how far we can go on a forum like this in educating you.

Therefore you have a responsibility to do some reading and educate yourself in these matters as part of your life long learning program.

Setting up a decent home HT requires a basic fount of technical knowledge and a grasp of the basic aspects of the engineering involved.

I really can't go further to explain this to you unless you are prepared to do some home work. You have to at least understand our language at a minimum, plus some of the physics behind audio reproduction.

 

[PearlcorderS701]

If the specs from Polk say your sub is 3 db down at 38 Hz, it certainly will not be better than that. So paper or not that is the way it is. Your unit can not reproduce the last musical octave no matter what you want to believe.

So I think you are optimal now. I have no suggestions, for improvement other than trying different locations.

A lot of your difficulties are due to lack of knowledge on your part of common terms and grasp of basic essential details.

There is a limit as to how far we can go on a forum like this in educating you.

Therefore you have a responsibility to do some reading and educate yourself in these matters as part of your life long learning program.

Setting up a decent home HT requires a basic fount of technical knowledge and a grasp of the basic aspects of the engineering involved.

I really can't go further to explain this to you unless you are prepared to do some home work. You have to at least understand our language at a minimum, plus some of the physics behind audio reproduction.

I should have learned my lesson the last time I was insulted by you with your harrangs of me being "too stupid" and what you now suggest above -- you like to throw these "educational slandering" bashings around when someone apparently doesn't know as much as you, and it's honestly disheartening and borders on frightening.

The best thing I can do at this point is to put your username on ignore and avoid further communication with you; to CONTINUOUSLY say that I am not grasping anything to the point that the "forum cannot help me" is absolutely ridiculous and walks the fine line of sounding "insane"...if I don't know as much as you, I'm considered "stupid." I gave you credit for the kind of beyond-reproach approach you have in this hobby based on your pictures, and you're still calling me "unable to be helped" in so many other words. That's just bewildering to me.

Again, I will stick with this notion: The majority of people in this hobby aren't running center speakers and surround channels that can OUTPERFORM a subwoofer -- ANY subwoofer -- in terms of tactile slam. If I am too stupid to understand why your situation is the norm, or why I don't believe the PSW350 isn't quite as bad as you say it is, so be it. I know I'm not that ignorant.

 

[TLS Guy]

I should have learned my lesson the last time I was insulted by you with your harrangs of me being "too stupid" and what you now suggest above -- you like to throw these "educational slandering" bashings around when someone apparently doesn't know as much as you, and it's honestly disheartening and borders on frightening.

The best thing I can do at this point is to put your username on ignore and avoid further communication with you; to CONTINUOUSLY say that I am not grasping anything to the point that the "forum cannot help me" is absolutely ridiculous and walks the fine line of sounding "insane"...if I don't know as much as you, I'm considered "stupid." I gave you credit for the kind of beyond-reproach approach you have in this hobby based on your pictures, and you're still calling me "unable to be helped" in so many other words. That's just bewildering to me.

Again, I will stick with this notion: The majority of people in this hobby aren't running center speakers and surround channels that can OUTPERFORM a subwoofer -- ANY subwoofer -- in terms of tactile slam. If I am too stupid to understand why your situation is the norm, or why I don't believe the PSW350 isn't quite as bad as you say it is, so be it. I know I'm not that ignorant.

I'm only using the Polk specs. They say it is 3 db down at 38 Hz. Since it is a ported box with a driver mounted on an exterior panel, it is a QB 4 box, by definition. So that means it rolls off at 24 db per octave. That is the physics of it. A box like that will behave like that for me, Polk or anyone else. So what that means is that your sub is 27 db down by 19 Hz.

I'm sorry if you are frustrated, but those are the natural laws of nature, and not mine.

 

[bandphan]

I should have learned my lesson the last time I was insulted by you with your harrangs of me being "too stupid" and what you now suggest above -- you like to throw these "educational slandering" bashings around when someone apparently doesn't know as much as you, and it's honestly disheartening and borders on frightening.

The best thing I can do at this point is to put your username on ignore and avoid further communication with you; to CONTINUOUSLY say that I am not grasping anything to the point that the "forum cannot help me" is absolutely ridiculous and walks the fine line of sounding "insane"...if I don't know as much as you, I'm considered "stupid." I gave you credit for the kind of beyond-reproach approach you have in this hobby based on your pictures, and you're still calling me "unable to be helped" in so many other words. That's just bewildering to me.

Again, I will stick with this notion: The majority of people in this hobby aren't running center speakers and surround channels that can OUTPERFORM a subwoofer -- ANY subwoofer -- in terms of tactile slam. If I am too stupid to understand why your situation is the norm, or why I don't believe the PSW350 isn't quite as bad as you say it is, so be it. I know I'm not that ignorant.

Im not here to burst bubbles... but... the 350 isnt going to cut it I do have a couple of subs for sale if interested, not world beaters but both can hold their own below 23hz

 

[anamorphic96]

Mike,

Have you tried the Onkyo with your mains set to large ? If not. Give it a shot. You have nothing to lose. You might be surprised at what the Onkyo can do.

I'm surprised at what my 506 can do.

As far as what TLS Guy has stated about your sub. He is correct. It is a bass module and not a subwoofer. I don't care how much you want to believe that it's more. It's not. It's physics plain and simple. He is correct in this regard.

So its simple. You have two options.

1. Set your mains to large and roll this way until you can purchase a new sub.

2. Do what you have been doing and use the 350 and find a spot that sounds good to you. We can't tell you where that is. Every room is different. So go with what sounds best to you. It's subjective and personal taste.

As far the phase and crossover go.

1. Leave the crossover on the sub set to 160 since you don't have a bypass. You leave it at 160 so it doesn't conflict with the receiver. The receiver will send everything from 80hz and below to the sub and the mains see 80hz and above and blend properly. The sub will not see anything above 80hz since the receiver is not sending the sub anything above 80. Your mains are doing this part. I hope this makes sense.

2. As far as phase goes. You typically go with the loudest setting. Which ever it is. When I set up my system with my SMS-1 I noticed nothing on my display when I inverted the phase. So I left it at 0. Most people do.