Explain this fequency info on PSW1000

jimed1

I just noticed that Polk has a new sub, the PSW1000. I was looking at the specs and don't know what this really means.

Overall Frequency Response 20Hz - 160Hz
Lower -3dB Limit 30Hz
Upper -3dB Limit 125Hz

What does it mean that the overall response is 20Hz on the low side, but the Lower -3dB limit is 30Hz.

All of the Polk subs specs are described in this way.
What I really want to know is this thing going to hit 20Hz or just 30Hz.

And for those of you that know, does this apply to the sacred SVS subs too. Like the 26-31 PC. Is the 26Hz a number from the overall response or the lower -3dB limit.

Ok all you speakers geeks, lets hear it...

PolkThug

It will play a 20Hz tone, but with much lower SPL's (loudness).

RuSsMaN

'Overall' is a 10db downpoint.

SVS's specs are at the 3db downpoint.

jimed1

Originally posted by RuSsMaN
'Overall' is a 10db downpoint.

SVS's specs are at the 3db downpoint.

So, are you saying that it plays 20Hz 10dB lower than it will play 30Hz?

I would think it would be 3dB lower since it says -3dB lower limit.

jimed1

BTW. This is the best looking sub I think Polk has ever made. The cherry in the picture is sharp.....

butynski

The PSW1000 is the LSiW with a new BASH amp.

I had the LsiW and was very impressed with its performance. I had been using a PSW1200 for now, hoping the LSiW would be back. I have already called my dealer to get me one on order.

The LsiW had a smoking problem (amp over heating) that is why Polk pulled them off the market.

jimed1

So you have ordered a PSW1000? How much, if you don't mind me asking.

I am wondering if this is the same amp used in the SVS.. Doesn't SVS use BASH amps? Is this an improvement for polk?

unc2701

Holy ****! I'm not the only person in the world with an LSiW... Well, i might be the only person who still has one. I just can't bear to let it go with out having something to replace it with. I guess I could go outside polk, but I just never was a fan of SVS/ HSU and that's about 90% of what you hear 'round these parts. Anyone know when the estimated release on the PSW1000 is?

unc2701

Also, is anyone else amused by this:

"Huge, fire-retardant flat NOMEX® Spiders provide highly reliable mechanical and thermal stability for safe, extended linear motion and long excursion bass."

Funny they should mention that it's fire retardant...

jimed1

I just ordered a PSW505 (used). I hope I like it. It is 300w with the bash amp too.

Did polk not buy back the LSiW's because they were a fire hazzard? You would think they would have to do something to ease the minds of those with one that hadn't fried yet.

bknauss

Assuming the electrical heading means the amplifier, and therefore assuming we're talking about the amplifier bandwidth, the -3dB point is lower.

jimed1

I just ordered a PSW505 (used). I hope I like it. It is 300w with the bash amp too.

Did polk not buy back the LSiW's because they were a fire hazzard? You would think they would have to do something to ease the minds of those with one that hadn't fried yet.

jimed1

Originally posted by bknauss
Assuming the electrical heading means the amplifier, and therefore assuming we're talking about the amplifier bandwidth, the -3dB point is lower.

I am lost. Please a little more detail into this topic without getting too technical.


Russman,
Same goes for your response. I don't understand downpoint.

RuSsMaN

3db down is all you need to be worried about, 10db is so far gone, it doesn't matter where it is anyway. The only thing that listing both a 3db and 10db downpoint does, is let you see how rapidly or gradually the freq response rolls off.

BK, don't you work for Polk? Why would you make a statement like that to confuse people? Of course it is the speaker response, not the amplifier.

-Russ

bknauss

That's why I put the "assuming"s in there... its under the electrical heading on the PSW1000 page. When I see a frequency response in relationship to electrical specs, that generally means its the performance of the amp, not the acoustic response of the system.

jimed1

I am still lost. What do those numbers mean in laymans terms as far as what I am going to hear. I still don't know what is meant by downpoint. Russman said it would hit 20Hz but at a lot lower volume than 30Hz. Am I to think that it will be 3dB less volume at 20Hz than at 30Hz?
Seems like I remember reading a long time ago that doubling amplifier power will only increase volume by 3dB. Is that correct?

Bknauss,
There is a separate section in the specs for amplifier but it only talks about watts and electrical connection.

PolkThug

20Hz will probably be 7db's less than at 30Hz, assuming 30Hz is 3db's less than 50Hz.

jimed1

Ok. I am going to have to read up on this.
How do you know to assume there is a 3dB drop from 50 to 30Hz and then translate that to 7dB drop from 30 to 20Hz?

PolkThug

Typically, "overall response" is +/- 10db's.

The given +/- 3db's reponse is 30Hz-125Hz.
The given overall response is 20Hz-160Hz.

So, 20Hz is -10db from the central point and
30Hz is -3db from the central point.

The difference between 30Hz and 20Hz is 7db (10db-3db)

Regards,
PT

fireshoes

The speaker will play from 30hz to 125hz without varying in volume more than 3db. It will produce sound from 20hz to 160hz but the sound will vary more than 3db higher or lower (probably 10 db).

jimed1

Originally posted by fireshoes
The speaker will play from 30hz to 125hz without varying in volume more than 3db. It will product sound from 20hz to 160hz but the sound will vary more than 3db higher or lower (probably 10 db).

Thanks,
Thats a lot closer to the kind of answer I was looking for, I think......LOL.

bknauss

Here's a copy and paste of the specs section of the PSW1000 page. Anyone else think the electrical section could possibly deal with the amp (especially since the crossover is spec'd there)? Or am I going nuts? I could be going nuts....





Driver Complement
Subwoofer 2 - 10" Diameter (25.40cm)
Dynamic Balance long-throw drivers with Polymer Composite cones

---

Electrical
Overall Frequency Response 20Hz - 160Hz
Lower -3dB Limit 30Hz
Upper -3dB Limit 125Hz
Power Handling (continuous) 400 w
Power Handling (peak) 825 w
Crossover
(subwoofer) 50Hz - 140 Hz

---

Dimensions
Cabinet Size 16-3/4" H x 16-7/8" W x 19-3/8" D
(42.55cm H x 42.86cm W x 49.21cm D)
Enclosure Type
(subwoofer) Vented via slot loaded Power Port

---

Subwoofer Amplifier Specs
Power Output 400 watts Continuous Average Output
Dynamic Power Output 825 watts
Power Requirements 120V or 240V AC 50/60 Hz
Available in 220V? Yes

jimed1

Thanks PolkThug.

I seem to have taken over this post with my incessant sub questions From reading some of your other I see that you like the SVS subs. You mention in another post that they are infrasonic and I am assuming that means we humans can't hear it. At what frequency does that happen and why is important. Is it simply because of the fact that we can feel it.

Say I had one of the SVS that was tuned to 16Hz, would it be loud playing at that frequency? I don't think I have ever seen a sub spec'd that low except for the SVS, but then I am not in the habit of looking at high-end equipment.

I have just bought a PSW505 and it should be here Friday. I am replacing a PSW350 with it. I think from looking at the specs on the 505, it may have a little better response than the PSW1000.

Would you agree?

Overall Frequency Response 23Hz - 160Hz
Lower -3dB Limit 28Hz
Upper -3dB Limit 125Hz
Crossover Variable low pass 60 - 125Hz, 4th order

I say this because the PSW1000 is
Overall 20Hz - 160Hz
Lower -3dB Limit 30Hz

So that mean that the 505 will play louder at 28 Hz than the PSW1000, right? Even though the low side of the overall reponse is not as low as the PSW1000.

Oh, and what does 4th order crossover mean. I know the higher the slope the better but I don't understand 4th order.

Thanks for your wisdom.

Everyone else keep chiming in. Just keep it simple. I don't have my EE degree yet.

butynski

When I had to return my LSiW, my dealer offered to loan me a PSW1200 until Polk came out with a replacement. I did this instead of refunding my money then buying a replacement sub. This gave me time to adduction a few different subs and see what Polk was going to do about a replacement. When I went to get the price of the PSW1000 I was told we could work it out if it was more than my store credit. In the past they have always treated my right.

Originally posted by jimed1
So you have ordered a PSW1000? How much, if you don't mind me asking.

I am wondering if this is the same amp used in the SVS.. Doesn't SVS use BASH amps? Is this an improvement for polk?

PolkThug

Bass below 20Hz is felt and not heard. You may not hear the bass frequencies directly, but you will often hear things in your room shaking, and the lower the frequency, the more further back in your room you may hear things.

When comparing infrasonic bass to regular bass, think in terms of sound pressure levels (SPL) instead of just the term "loud". So, subs like those made by SVS can have just as much SPL at 17Hz, as they do at 25Hz.

Regards,
PT