PSA: Things that go Thump in the Night

[USNRET]

Nismo....not quite understanding....when I start calibration...it is looking to have the sub or subs at 75db ....how is this done if the gain is at 100%....

Am I missing something

With my PSAs I have to turn the gain way down to meet the 75db level but then that doesn't begin to get bass much less THUMP in my cavern so I use the pre/pro's sub level adjust to bring them up to what I like at the couch.

[Nismo]

I would venture to say that the room size control shift the FR from a lower extension mode to a higher output mode.  Every db of extra extension cuts output by around 1 db.

So if I understand correctly, based on the setting; small or large.... it would act like an attenuator to dial back the (lower) frequencies (extension) when set to small.

 

Would it minimize only the FR (not dig a s deep), or does it adjust output levels too?

 

Or at that point are the output levels primarily controlled via the  signal from AVR.

 

Conversely, when set to large... it would then provide maximum capabilities?

[Nismo]

 

Nismo....not quite understanding....when I start calibration...it is looking to have the sub or subs at 75db ....how is this done if the gain is at 100%....

Am I missing something

With my PSAs I have to turn the gain way down to meet the 75db level but then that doesn't begin to get bass much less THUMP in my cavern so I use the pre/pro's sub level adjust to bring them up to what I like at the couch.

 

Hmmm. for me it was just the opposite. Out of habit (based on previous subs I've owned) I initially have gain set at 11:00 or 12:00 position when beginning calibration. With the XS30se, I needed to advance the gain to 1:00 o'clock -almost 2:00 o'clock for the 75dB baseline. But regardless Tom V. said no worries, some amps just have more sensitive gain controls than others, the gain just controls the sensitivity of the input jack based on the signal from the AVR (nothing really to do with maximum output capabilities). 

 

Seems to me (at least in my space, with my positioning & orientation of both front & rear drivers) that Audyssey was having calibrating issues. Placement is front left corner (I cannot do near field behind the MPL), so with the 15" front driver pointed at the MLP, with the 15" rear driver pointed at the wall... that was a lot of LFE & output coming from just one side of the 13' x 16' room. Audyssey was overcompensating with distance & cutting back levels. With levels cut back from the source (the AVR)... my gain levels needed to be advanced higher based on the input signal it was receiving. Hope that makes sense.  

 

We both have the same amp & the same gain structure, so I guess our rooms & placements require different gain control to achieve the 75dB baseline.

[derrickdj1]

Remeber, I am speculating.  Ask PSA and see if they want to share their secret, lol.  I consider all of my subs as one unit.  I can EQ the response for low extension or max output.  But, you can't do both.  Depending on room size, one option may be better than the other.  For example, in a smaller room with a lot of cabin gain, the low extension mode may have excellent output and extension.  On the other hand, a large room with little cabin gain trying for max extension may loose enough output and the extra extension is of no benefit and cost output higher up.

[Nismo]

Nismo....not quite understanding....when I start calibration...it is looking to have the sub or subs at 75db ....how is this done if the gain is at 100%....

Am I missing something

Every room & placement will have different demands. Gain control is not the same as volume control. When setting at 75dB (for calibration set up) gain control provides adjustment based on the input signal it receives from your AVR (its not a gauge or indicator of reaching maximum output capabilities of the sub).

 

Since every AVR or processor might be sending a different signal strength to the sub, the gain structure (or sensitivity) will vary, especially when calibrating to various/different room sizes.

 

You might not have to have the gain set at 100% in your space (for 75db).  Tom V. just mentioned to me (for comparison sake) that an ICE amp has different gain structure & is more sensitive  when compared to a BASH amp. In the same room an ICE amp could have gain at 1/3... while a comparable BASH amp could be at 2/3 or even higher. Even if it required 100%... no  real concern because that's not an indication of the the sub reaching it maximum capabilities, you can still adjust sub levels (volume/output levels via the AVR or processor via setting after calibration).

 

Your room & space will determine the gain level needed during calibration. In my case the gain wound up being near the 2:30 position (5:00 is max), then (after calibration) I bumped up sub levels via the AVR in order to increase output levels that were effective. 

[cradeldorf]

you made me remember why I went back to two channel.

[oldred]

I understand what you are saying.....I have never had any sub I have owned set at 100%.......everything from

Velodyne....SVS....Definitive Tech.....Klipsch Rsw......even back in the day before auto calibration.....remember the trusty RS slm.....Don't get me wrong now when calibration is complete I do kick each sub up a couple notches....but that brings them up to #5......but 100%....I aways thought the reason my were set so low to achieve 75db was because RSW rear is active and mine are in a corner stacked about 15 inches from wall.

100%.   Come on.....So when calibration starts do you just disregard the 75db??

Edited September 24, 2015 by oldred

[CECAA850]

 

I would venture to say that the room size control shift the FR from a lower extension mode to a higher output mode.  Every db of extra extension cuts output by around 1 db.

So if I understand correctly, based on the setting; small or large.... it would act like an attenuator to dial back the (lower) frequencies (extension) when set to small.

 

Would it minimize only the FR (not dig a s deep), or does it adjust output levels too?

 

Or at that point are the output levels primarily controlled via the  signal from AVR.

 

Conversely, when set to large... it would then provide maximum capabilities?

 

 

I don't see how that would work without changing the porting (if we're talking about a ported sub).  I don't see how it would work with sealed either.

[Nismo]

 

 

I would venture to say that the room size control shift the FR from a lower extension mode to a higher output mode.  Every db of extra extension cuts output by around 1 db.

So if I understand correctly, based on the setting; small or large.... it would act like an attenuator to dial back the (lower) frequencies (extension) when set to small.

 

Would it minimize only the FR (not dig a s deep), or does it adjust output levels too?

 

Or at that point are the output levels primarily controlled via the  signal from AVR.

 

Conversely, when set to large... it would then provide maximum capabilities?

 

 

I don't see how that would work without changing the porting (if we're talking about a ported sub).  I don't see how it would work with sealed either.

 

The room size control attenuates the bass. I was just trying to understand when you begin to control it towards "small" does it attenuate the extension, the output.... or both. 

[minermark]

Congrats on the sub purchase, you should be rocking well these days.

Looking at the PSA site, i saw this Bad Boy, Dam Man, we are talkin some thumping here.

http://www.powersoundaudio.com/collections/subwoofers/products/t18

[Nismo]

I understand what you are saying.....I have never had any sub I have owned set at 100%.......everything from

Velodyne....SVS....Definitive Tech.....Klipsch Rsw......even back in the day before auto calibration.....remember the trusty RS slm.....Don't get me wrong now when calibration is complete I do kick each sub up a couple notches....but that brings them up to #5......but 100%....I aways thought the reason my were set so low to achieve 75db was because RSW rear is active and mine are in a corner stacked about 15 inches from wall.

100%.   Come on.....So when calibration starts do you just disregard the 75db??

 

I guess that was what I was attempting to explain. Non of my previous 6-or-7 subs owned have required gain to be set above 12:00 - 12:30 position when calibrating.... but Tom V said its a moot point & is not of concern (or any indication that the sub is reaching or has achieved maximum output). Since the gain control only amplifies the "input signal" received from the AVR (it does not function as a true volume control, actual "volume" is controlled by the "level" setting via the AVR either manually or via Audyssey calibration).

 

Some amps have a sensitive gain structure & will only require a subtle gain adjustment say, 10:00 - 12:00 position. By contrast the particular BASH amp with the XS30se is less sensitive (when controlling the input jack, based in the input signal) & thereby will require a higher setting than an amp with a more sensitive gain control..3 clicks on an ICE amp... would require 6 clicks on a BASH amp for similar adjustment to achieve the same "advance". In my space (out of habit) I began initial calibration with it set to 12:00... only having to raise the gain control higher to achieve 75dB in my space. It was only after calibration did I notice the gain was positioned around  2:00-2:30 (when  matching 75db levels).

 

But despite setting it at 75dB, after calibration was complete, "audible" base was not evident during actual playback. In my instance Audyseey was doing funky things with distance & actual sub channel levels, and overcompensated (dialed back levels, etc.) based on my placement (front left corner, one 15" driver facing MLP, and the other 15" driver facing the front wall. That was a lot of LFE & output hitting just one corner of the room, so Audyessey was having trouble accurately measuring frequencies under 40Hz.  Audyssey dialed down the input signal being sent to the sub & thus the gain control (required to achieve 75dB) needed to be advanced accordingly to amplify the attenuated signal it was actually receiving. Once I performed that & also corrected my distance & bumped up sub channel levels in the AVR... the XS30se came alive & delivered solid extension & output.

 

I guess long story short, Audyssey was over correcting in my space, so the (less sensitive BASH) gain control had to be advanced to compensate for what Audyssey was doing on the front end. And having gain control set 75% or near 100% is not of any concern (or indication the sub has reached maximum output).  The process was just different than I normally experience with any other sub placement & calibration. What setting you have, will depend on what your space demands when initially achieving 75dB. But don't be concerned with having to set gain higher than normal & then after calibration is complete (if still needed, as was in my case) bump up sub levels 2-3-4-5 dB via the AVR after calibration (to address any over compensation that Audyssey registered). 

Edited September 24, 2015 by Nismo

[Nismo]

Congrats on the sub purchase, you should be rocking well these days.

Looking at the PSA site, i saw this Bad Boy, Dam Man, we are talkin some thumping here.

http://www.powersoundaudio.com/collections/subwoofers/products/t18

The feedback & reviews all say that the T18 is an impressive performer indeed. Triple 18" drivers from PSA.

 

One customer had (4) T18's.... stacked 2 x 2 in his space. wow. 

[TasDom]

The V3600's are huge!

 

 

 

http://www.avsforum.com/forum/113-subwoofers-bass-transducers/1372020-official-power-sound-audio-subwoofer-thread-753.html#post37520818

 

 

[CECAA850]

Anytime I've calibrated any system flat it sounds horrible.  The LFE channel normally needs about 6dB over flat to sound normal (to me).

[Nismo]

Anytime I've calibrated any system flat it sounds horrible.  The LFE channel normally needs about 6dB over flat to sound normal (to me).

I think we are describing two different things. Starting out flat, calibrating, then bumping things up after the fact (to one's preference) is normal.

 

I'm talking about the need to start with levels & gain bumped up prior to calibration, because in my case Audyssey was overcompensating during calibration.

 

When normally, one should start out flat.

[oldred]

Nismo,...Well I have to say I kinda understand ...Audyssey is good ...but does have it's qwerks... After getting home from work I decides to look and see exactly how Audyssey reacted to my subs in my space again....Started calibration   both subs 3 notches up from 0 (RSW's do not have #'s) to achieve 75 db....went through calibration Audessey decided to bring the subs up 5 db from there....brought fronts down 9..... center down 6.....  surrounds down 7.... rears down 7....this may sound harsh....what the ....is the 75 db on the sub for if Audyssey  brings it up anyway??

Hope that doesn't sound stupid

 

That is why I kinda understand

[Scrappydue]

The 75db starting point is STUPID in my opinion. If you call Svs they will tell you to turn the gain up as far as possible to get the subs just in calibration level. So if your sub trim goes down to -12 like mine they want their subs up as far as possible to get calibrated at say -11 to -9 area. I calibrate my 18's with gain at 50% which brings trim to -3.5 on mine. I then boost to +.5 and leave it. Never adjust for music or movies. Used to always leave it flat and it has plenty of bass but I'd turn it up 6db for music. Well 6db is too much on movies for me so 4 db was my magic number so I don't mess with it anymore.

[TomV.]

Hi all,

The "room size" control gradually attenuates the deeper bass as your turn it to SMALL. This will help integrate subwoofers into smaller rooms that may have an excess of "room gain" which is sometimes called "pressure vessel effect".

 

You can see the electrical here.

 

https://www.facebook.com/powersoundaudio/photos/pb.116310328477678.-2207520000.1445535359./700349743407064/?type=3&theater

 

And how the control adjusts the actual output of a subwoofer(The V3600i) here

 

https://www.facebook.com/powersoundaudio/photos/pb.116310328477678.-2207520000.1445535351./736415589800479/?type=3&theater

 

TomV.

[CECAA850]

Thanks for the clarification Tom.

[wvu80]

Hi all,

The "room size" control gradually attenuates the deeper bass as your turn it to SMALL. This will help integrate subwoofers into smaller rooms that may have an excess of "room gain" which is sometimes called "pressure vessel effect".

 

You can see the electrical here.

 

https://www.facebook.com/powersoundaudio/photos/pb.116310328477678.-2207520000.1445535359./700349743407064/?type=3&theater

 

And how the control adjusts the actual output of a subwoofer(The V3600i) here

 

https://www.facebook.com/powersoundaudio/photos/pb.116310328477678.-2207520000.1445535351./736415589800479/?type=3&theater

 

TomV.

 

Thank you, Tom,  nice first post. 

 

Welcome to the forum.