# Please help me with my 20dB+ peak and 10dB dip!



## Guest (May 11, 2007)

Hi,

I have managed to measure the frequency response of my PB12+/2 using REW and in my room, the response is pretty bad with a very strong bias towards the low end of the spectrum (20hz to 45hz) and I have quite a big dip at 53hz - cross-over is set at 80hz.

My rectangle-shaped room is pretty small measuring at only 1600 cu ft so placement of the sub is very limited. The dip at 53hz is there regardless of what I have the subs phase at and I was wondering if it was possible to bring everything down so that it is in-line with the dip i.e it doesn't become a dip any more.

Or would it be safe to use a 10dB boost at 53hz without any detrimental effect on the sub?

Any help would be much appreciated.

Thanks


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## brucek (Apr 11, 2006)

Turn off your mains, so we can see the sub by itself......

The dip at 53Hz is not a problem and not likely noticeable.

It's the mountain from 20Hz to 50Hz that you should be concerned about. Yikes. Bring it down to the target.

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

> I was wondering if it was possible to bring everything down so that it is in-line with the dip i.e it doesn't become a dip any more.


As soon as you turn your sub up to account for the *~35 dB loss*  it may come right back. 

Not to mention, we’ve seen here that such drastic cutting can cause other problems. For instance, you could end up with too low a level to drive your sub to its maximum output. Or get substantially increased noise from having to turn the sub’s gain up so high to compensate.

This is probably going to be difficult if not impossible curve to equalize. The “distance” between your relative low area between 60-100 Hz and the peak at 39 Hz is just too great. I suggest trying other locations, such as a corner, if that’s not where it is now.

Regards,
Wayne


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## brucek (Apr 11, 2006)

> This is probably going to be difficult if not impossible curve to equalize


Yeah. I'd like to see his sub only though to get a better idea of what we're looking at. He may have to move the sub to get a more reasonable response.....

brucek


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## Guest (May 12, 2007)

Wayne A. Pflughaupt said:


> As soon as you turn your sub up to account for the *~35 dB loss*  it may come right back.
> 
> Not to mention, we’ve seen here that such drastic cutting can cause other problems. For instance, you could end up with too low a level to drive your sub to its maximum output. Or get substantially increased noise from having to turn the sub’s gain up so high to compensate.
> 
> ...


Hi, 

I have measured the subs frequency-response around different parts of the room but there is always a big boost from 20hz to around 45hz. The only place where the response was more even was when I measured at the center of the room, however due to the small size of the room, it would be impossible to move the seating possition there.

After re-arranging certain things in my room, there was another spot where I could move the sub and I am happy to report back that the 53hz dip is now gone but the peak at 40hz is still there.

I have used 3 filters to tame 20hz to 45hz and this is the result:

The largest gain I had to use was -16dB. Do you think that this is ok?


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## brucek (Apr 11, 2006)

Looks pretty **** good. Does it sound OK?


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## Guest (May 13, 2007)

brucek said:


> Looks pretty **** good. Does it sound OK?


It diffently sounds better now - the frequencies below the the peak is more noticable now that everything has even out.

It appears that when I was watching films at very high-volume levels, after awhile the bass became fatiquing due to the peak at 40hz.

Now, I don't get a headache anymore lol:T 

I'm guessing that this flatter response is probably as good as I'm gonna get it in my room but does anyone think it can be improved further?

Thanks


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## brucek (Apr 11, 2006)

> does anyone think it can be improved further?


Not really. You can call that your house curve. Most people actually try and get the exact curve that you have.....

brucek


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## Otto (May 18, 2006)

You can tweak all you want, and you may be able to make it "better", but that's a very good curve.

Good job.


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## Jerm357 (May 23, 2006)

If it sounds Good, roll with it. 16db is a pretty big cut though. Wheres that big cut at?


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## Guest (May 13, 2007)

Jerm357 said:


> If it sounds Good, roll with it. 16db is a pretty big cut though. Wheres that big cut at?


The -16dB cut was applied to the 40hz peak.

Here is how the sub is set-up:

The subs gain control starts from 7 o clock and and ends at 5. I had it set at 9 o clock with the sub-channel on my Denon 3805 at-10dB in order to calibrate with the rest of my speakers to 85dB using Avia.

Now after applying the the filters, the subs gain control is still at 7 o clock but had to increase the sub-channel to 00dB (an extra 10dB) to compensate for the huge 16dB cut. 

After playing through some scenes from my reference movies with low LFE, I am still getting 110dB+ of clean bass and with no signs of stress or compression.

I just hope this 16dB cut doesn't cause any long-term damage to my sub...


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## Otto (May 18, 2006)

Hi there,

I don't think there's anything wrong with a 16 dB cut, and it should do no damage to your sub.


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