What cheap subwoofers don't give you. - AVS Forum
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post #1 of 27 Old 01-18-2013, 06:24 AM - Thread Starter
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I've noticed that a lot of people around here recommend the Polk PSW 505 subwoofer. As a person who has built a number of his own subwoofers I've wondered about how good this product really is in the cosmic scheme of things.

Please don't interpret this post as a critique of the PSW 505 as being a bad value. It has been sold lately for less than $200 and at that price it is not that much more expensive than its cabinetry. As I've said before I've built my own subwoofers and I've paid much more than $200 for just the subwoofer driver, and then spent more than $200 for the power amp to drive it. I've also spent more than $200 for just the active crossover. So, in some sense a $200 subwoofer that actually does something is a bit of a marvel!

As many of you know I've been running a computer model that estimates the capacity of speakers to deliver clean sound as a function of frequency. I decided to use it to see if I could figure out some things about the PSW 505.

I found that an energetic AVR member had run some tests on his own PSW 505 and posted the following graph that I've plotted some more information from the computer model onto:



The first line I added is the black line that is my model for a speaker with a 12" diaphragm and 6.5 mm Xmax. The way that it sits on top of the results for the actual measurement suggests to me that the Xmax of the PSW 505 driver roughly in the 6 or 8 mm range which is well below that achievable with the best available subwoofer drivers. Of course a SOTA 12" driver runs 2-4 times the price of an entire PSW 505 system!

Just for grins I added the red line that shows an estimate of the performance of a SOTA driver with a 12" diaphragm and 30 mm Xmax. Basically, everything below 50 Hz is about 15 dB louder which is quite a bit and would sound really cool if you like to crank things up a bit. This driver might require quite a bit more power to do its best - maybe a kilowatt or two.

One point I see is that no way is it fair to characterize subwoofers based on just the size of their drivers because Xmax can vary so much for a given driver size. My current subwoofer is a far more expensive unit that also has a 12" driver that I hope has far more Xmax than the PSW 505. However there's no way to find out whether or not that is true from most vendor spec sheets, and/or published tests by third parties.
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post #2 of 27 Old 01-18-2013, 06:33 AM
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But four of them spread around a room...
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post #3 of 27 Old 01-18-2013, 07:11 AM
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...would be a bad idea.

Bass waves should radiate from a point source. Multiple subwoofers tend to interfere with each other rather than reinforce each other. Two are manageable if placement is carefully done, but more than two seldom works well at all.
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But four of them spread around a room...
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post #4 of 27 Old 01-18-2013, 07:14 AM
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The PSW505 is a long way from being the best subwoofer in town.

On the other hand, for someone who can't afford $400-700 for a really good sub, it seems to be the best by far for $200. There isn't much else that competes with it at that price...is there?

For someone who has a wimpy underpowered 8-inch or 10-inch piece of crap, it is a major improvement on the cheap.
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post #5 of 27 Old 01-18-2013, 07:18 AM
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Quote:
Originally Posted by commsysman View Post

...would be a bad idea.

Bass waves should radiate from a point source. Multiple subwoofers tend to interfere with each other rather than reinforce each other. Two are manageable if placement is carefully done, but more than two seldom works well at all.

eek.gif

You really should do some reading dated within the past 20 years
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post #6 of 27 Old 01-18-2013, 07:19 AM
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Quote:
Originally Posted by commsysman View Post

...would be a bad idea.

Bass waves should radiate from a point source. Multiple subwoofers tend to interfere with each other rather than reinforce each other. Two are manageable if placement is carefully done, but more than two seldom works well at all.
That claim runs contrary to.. well, everyone in the industry.

We can start with every pro setup in existence (which use dozens or more of every type of driver).
We can include movie theaters, dance clubs, and sports arenas in the above.

http://stereos.about.com/od/optimizingperformance/a/multiplesubs.htm
http://www.soundandvisionmag.com/article/subwoofers-4-2-or-1-0?page=0,3
https://docs.google.com/file/d/0BxgUOGOB5HbfR0JTRF9XZjkyUms/edit?pli=1
http://www.audioholics.com/tweaks/get-good-bass/multiple-subwoofer-setup-calibration-1
http://velodyne.com/tech/the-benefits-of-using-multiple-subs
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post #7 of 27 Old 01-18-2013, 07:23 AM
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Quote:
Originally Posted by commsysman View Post

...would be a bad idea.

Bass waves should radiate from a point source. Multiple subwoofers tend to interfere with each other rather than reinforce each other. Two are manageable if placement is carefully done, but more than two seldom works well at all.

Wrong as usual. At least you're consistent.
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post #8 of 27 Old 01-18-2013, 07:31 AM
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Well, everyone is an expert here.

I'm certainly glad that providing some facts has stimulated some discussion, however questionable its basis.
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post #9 of 27 Old 01-18-2013, 07:53 AM
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Quote:
Originally Posted by commsysman View Post

...would be a bad idea.
Bass waves should radiate from a point source. Multiple subwoofers tend to interfere with each other rather than reinforce each other. Two are manageable if placement is carefully done, but more than two seldom works well at all.

Can you provide something to back it up thats its a bad idea to have more than two subwoofers?

One subwoofer may be enough output wise, but multiples can give a much smoother freq response at the main listening seat as well as across multiples. Theres things called nulls and peaks that is caused by the room. Mulitples can solve those problems or atleast improve the response. Audyssey can even go a little further in helping improve decay times (boomyness cause by reflections/bouncing) and knocks down peaks (boosted freqs from again the room)
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post #10 of 27 Old 01-18-2013, 07:59 AM
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Originally Posted by gtpsuper24 View Post

Can you provide something to back it up thats its a bad idea to have more than two subwoofers?
It's not a bad idea; quite the contrary. Most experts in the field agree that the best result will be had with four subs, strategically spread around the room. Even better results will usually be had with more than four, but the law of diminishing returns sets in at four, so having more than that won't have nearly as obvious an effect as four compared to two, or two compared to one.

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post #11 of 27 Old 01-18-2013, 08:11 AM
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Originally Posted by commsysman View Post

Well, everyone is an expert here.

Not everyone...
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post #12 of 27 Old 01-18-2013, 08:17 AM
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All one has to do is Google "benefits of multiple subwoofers". In a nutshell you'll come away with what Bill has said. Finding facts aren't hard.


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post #13 of 27 Old 01-18-2013, 08:19 AM
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Quote:
Originally Posted by bfreedma View Post

Not everyone...
http://www.youtube.com/watch?v=FdghRwWfaOQ&feature=related

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post #14 of 27 Old 01-18-2013, 08:33 AM
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I don't have any fancy graphs, but I did an A/B test between my HSU sub and my friend's 12" Polk (can't remember the model) a couple of years ago. There was simply no comparison. The HSU played deeper, punched you in the chest (in a good way), and didn't distort at high volumes. The Polk (almost literally) fell apart at higher volumes.

In general (with all products, not just HT gear), I try to save up to buy something that will last rather than buying something I know I will replace in 2 years. That's just throwing money away.
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post #15 of 27 Old 01-18-2013, 08:42 AM
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Quote:
Originally Posted by bfreedma View Post

Not everyone...

AH HA HA!!!!

On a rare occasion, commsysman will post something that is reasonable and makes me think he, somewhat, knows a thing or two... Then, we have the typical, off the wall post he'll make and it just has me scratching my head! LOL!

At any rate, I have two subs, with two ten inch drivers in each cabinet and things shake quite nicely. I don't notice any resonance or odd frequency problems... rolleyes.gif

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Of course, I got it modified with the TK-427, which cheeks it up another, maybe, 3 or 4 quads per channel.
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post #16 of 27 Old 01-18-2013, 09:06 AM
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Like I said, two can work quite well if placed properly.

I have two Vandersteen subs at one home.

My experience has been that MORE THAN TWO (which is what I SAID), are problematical; not impossible, mind you, but perhaps difficult to get working well.

I'll bet you 10 to 1 that any experienced home theater installation pro will tell you the same thing.
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post #17 of 27 Old 01-18-2013, 09:13 AM
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Quote:
Originally Posted by commsysman View Post

...would be a bad idea.

Bass waves should radiate from a point source. Multiple subwoofers tend to interfere with each other rather than reinforce each other. Two are manageable if placement is carefully done, but more than two seldom works well at all.

Quote:
Originally Posted by commsysman View Post

Like I said, two can work quite well if placed properly.

I have two Vandersteen subs at one home.

My experience has been that MORE THAN TWO (which is what I SAID), are problematical; not impossible, mind you, but perhaps difficult to get working well.

I'll bet you 10 to 1 that any experienced home theater installation pro will tell you the same thing.

That's not what you said at all. Multiple = more than one. And you would still be wrong as multiple subs are not typically problematic.

And I'll take that bet - how much do you want to put into escrow before we ask properly certified installers about the value and the difficulty (or lack thereof) of implementing multiple subs. How about I put up my $100 against your $1000?
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post #18 of 27 Old 01-18-2013, 09:18 AM
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By multiple, I meant more than two. I think the context made that quite clear, but if one chooses to not read the entire paragraph, and then intentionally misinterpret a couple of words, one COULD attempt to draw some other meaning out of it. ("more than two seldom works well at all"...).

If that does not agree with your definitions or semantics, then what I meant is now completely clarified for you.

Do you understand what "TEND TO" means?

I never bet more than $1.00. Got ten cents?

biggrin.gif
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post #19 of 27 Old 01-18-2013, 09:34 AM
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Quote:
Originally Posted by commsysman View Post

By multiple, I meant more than two. I think the context made that quite clear, but if one chooses to not read the entire paragraph, and then intentionally misinterpret a couple of words, one COULD attempt to draw some other meaning out of it. ("more than two seldom works well at all"...).

If that does not agree with your definitions or semantics, then what I meant is now completely clarified for you.

Do you understand what "TEND TO" means?

I never bet more than $1.00. Got ten cents?

biggrin.gif

Without bothering to address your redefinition of the word "multiple", your basic statement about multiple subs is incorrect by either use of the word.

Don't propose bets you don't intend to take. Bad form.
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post #20 of 27 Old 01-18-2013, 09:55 AM
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Quote:
Originally Posted by commsysman View Post

The PSW505 is a long way from being the best subwoofer in town.

On the other hand, for someone who can't afford $400-700 for a really good sub, it seems to be the best by far for $200. There isn't much else that competes with it at that price...is there?

For someone who has a wimpy underpowered 8-inch or 10-inch piece of crap, it is a major improvement on the cheap.

Newegg has a 10" energy sub for sale around $200 from time to time. I would take that over the Polk. There are a few bics in the same price range I would pick also. There's nothing special about the Polk.
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post #21 of 27 Old 01-18-2013, 10:01 AM
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Originally Posted by KidHorn View Post

Newegg has a 10" energy sub for sale around $200 from time to time. I would take that over the Polk. There are a few bics in the same price range I would pick also. There's nothing special about the Polk.

If you mean the Energy s10.3 that subwoofer it isn't available anymore. You might get lucky and find one on ebay though.

If you mean the new Energy Power 10 subwoofer that thing is a piece of crap. Low end is 45hz and it has a 50W amp. Might as well get a Polk PSW110 for half the price.

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post #22 of 27 Old 01-18-2013, 10:13 AM
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I'm not trying to throw myself into the cage here but..

I've heard the Klipsch RW-12d is pretty good, in fact, I just purchased one.
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post #23 of 27 Old 01-18-2013, 10:52 AM
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CV makes some good subs for under 400..
Love my CV's
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post #24 of 27 Old 01-24-2013, 02:07 PM - Thread Starter
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Quote:
Originally Posted by JerryLove View Post

But four of them spread around a room...

Or even just two. They are far, far, far from being the best subwoofers around - so far from it that the suggestion that anybody would think so might even be a bit insulting. But if you can score one or two for $200-250 a piece, not such a bad deal, it appears!

The tough trick is finding objective test results, particularly for cheap subwoofers. I just happened to find this data for the PSW 505 by accident.
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post #25 of 27 Old 01-24-2013, 02:24 PM
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Quote:
Originally Posted by GaryWA View Post

I'm not trying to throw myself into the cage here but..

I've heard the Klipsch RW-12d is pretty good, in fact, I just purchased one.

I'm actually considering picking this up for my new budget 7.1 set up. It's $300 at Newegg. Should I save $100 and go with the Polk PSW505?
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post #26 of 27 Old 01-24-2013, 03:00 PM
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If the Klipsch is only $100 more I would go with it. It is a better performer than the Polk especially for $300. I would only consider the Polk if the Klipsch goes back up in price to $499 then the Polk is a better buy.
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post #27 of 27 Old 01-24-2013, 03:03 PM
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Ground plan reading don't tell the full story

If you look at that guys in room frequency response he had great results with the Polk PSW505 flat to 25hz

For $200 the Polk PSW505 is an amazing deal but any dollar amount over $200 there are better options.

If a person can spend more than $200 I recommend them do that. The Klipsch RW-12d is a must buy
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