# pb 13s amp maxing out??



## misko (Feb 15, 2010)

hi everybody,this forum was very helpful in past for me,found a lot of answers..

But now i think i have a problem with my sub.
If i turn the volume knob past 12oclock position it plays considerably not as loud as before 12oclock.Could it be that amp is in its max output?The preamp is bryston SP1.7,and the bass limiter is disabled. 

thanks for replies.

mike


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## tonyvdb (Sep 5, 2007)

Hi and welcome to the Shack.

This does seem strange as usually the driver will bottom out before the amp will run out of steam. Are you certain that you are turning the level adjustment and not one of the other settings?


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## misko (Feb 15, 2010)

thanks for reply..
yes im sure its the volume knob,could be something wrong with the amp?

mike


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## tonyvdb (Sep 5, 2007)

Hmmm, there could be, I would check that you have the output of the preamp set to a reasonable level (not too hot) Usually around -4 to +2 is normal.


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## misko (Feb 15, 2010)

preamp is set at -2db.


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## tonyvdb (Sep 5, 2007)

Is your room fairly large and have you done a proper calibration of the system using an SPL meter?


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## misko (Feb 15, 2010)

my room is small,around 1300cu/ft.
Didnt used spl meter,though(i dont have one)


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## tonyvdb (Sep 5, 2007)

I would suggest contacting SVS and see what they have to say. They are very helpful and may have an idea.


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## misko (Feb 15, 2010)

i will contact them


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## Ed Mullen (Jul 28, 2006)

The BASH amp limiter is engaging.

Remember, it’s not a volume control, it’s a gain control. The calibration level of the subwoofer (relative to the speakers), is a function of the voltage at the amp input, and the amount of gain added at the amp. 

If the voltage at the amp input is high, then less gain will be needed at the amp. Conversely, if the voltage at the amp input is low, then more gain will be needed at the amp. Once the total gain required to calibrate the subwoofer level is established, the gain control at the amp should not be touched again. And dialing in more gain at the amp will only cause the limiter to engage - the subwoofer is protecting itself from being overdriven.

If the pre/pro lacks auto-calibration, the speakers and subwoofers must be manually calibrated using a source of test tones like Avia and an SPL meter. If you don't have an SPL meter, you can purchase one from L-sound.

Also, considering the size of your room, I recommend you set the room gain compensation control to Small, which will roll-off the response earlier to compensate for excessive room gain in a small room like yours. This will also reduce the amount of power required by the amp and will further help to keep the amp limiter from engaging. 

After proper set-up and calibration, a single Ultra will get quite loud in a 1300 ft^3 room without the limiter engaging.


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## misko (Feb 15, 2010)

Thats what i call customer service...
I mailed L-sound and they repplied me almost immediately,...
Not to mention Ed Mullen...outstanding.

problem solved(explained)

thanks guys for all the replies...

mike


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## XxxBERRYxxX (Sep 13, 2007)

You must have been running that thing way to "HOT".


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## macmovieman (Dec 7, 2010)

Glad you got it working. SVS is the best and I am loving my new PBUltra13.


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