subwoofer and dynamic EQ question

[Brian Steele]

(I posted this across at the PE "Pro Audio" form, but no suggestions there yet...)

The Behringer NU3000DSP amp has a "dynamic EQ" feature that provides two bands of dynamic EQ with variable Q, center frequency, attack, etc.

If I have a subwoofer where the driver can take up to 350W, but the power-handling at about 50Hz in the alignment that its in drops to just under 100W due to excursion limitations, how can I use the dynamic EQ feature to get the most out of this subwoofer and at the same time protect it from over-excursion in its passband?

I suspect it's not as simple as just choosing a "Q" that's the closest match to the excursion curve at the center frequency, and then setting the gain and threshold to around -5dB...

 

[chris661]

I suspect it might be that simple, though Behringer's dynamic eq does seem a little odd to me.

Problem is, of course, that you can't try it and see without putting some equipment on the line.

Chris

 

[Zero D]

I think you are on a hiding to nothing with that driver !

Sure you could arrange for the DEQ to boost to the drivers power limit @ whatever "suitable" f and or f's, but as you suspected, you would need to reduce the overall level to compensate.

 

[Brian Steele]

I suspect it might be that simple, though Behringer's dynamic eq does seem a little odd to me.

My idea might work if the DEQ starts working at the threshold and increases in magnitude at higher levels. However, if it decreases in magnitude at higher levels, it would make things worse, LOL

Problem is, of course, that you can't try it and see without putting some equipment on the line.

I could try it and measure the results via a series of quick sine sweeps at higher and higher levels. That should not cause any equipment failures.

 

[sreten]

Hi,

You might set it to -10dB and 1:2 at 50Hz , but
it won't protect your speakers in any real sense
for home use, makes more sense live / PA.

There are no Q setting for high pass mode.

Its basically a compressor, and most bass is
already heavily compressed and doesn't need
any more compression. Its not a power limiter
and won't control maximum power to the driver.

What it can do is what it says on the tin, dynamic EQ.

Which you have to understand properly to understand
the correct settings, including attack and release, and
the nominal high pass function being dynamically applied.

It can make a sub go a lot louder properly applied, and
prevent a sub that sounds fine at low levels sounding
boomy at high levels, but a lot of tweaking is involved.

rgds, sreten.

Dynamic EQ, basically progressively rolling off the bass
as the drive to the speaker gets larger certainly works,
but is not real hifi. Nevertheless it works amazingly well
on my computer speakers, and probably does with many
AV subwoofers that are really too small to do the real job.

 

[Brian Steele]

Hi,

You might set it to -10dB and 1:2 at 50Hz, but
it won't protect your speakers in any real sense
for home use, makes more sense live / PA.

There are no Q setting for high pass mode.

Its basically a compressor, and most bass is
already heavily compressed and doesn't need
any more compression. Its not a power limiter
and won't control maximum power to the driver.

What it can do is what it says on the tin, dynamic EQ.

Which you have to understand properly to understand
the correct settings, including attack and release, and
the nominal high pass function being dynamically applied.

It can make a sub go a lot louder properly applied, and
prevent a sub that sounds fine at low levels sounding
boomy at high levels, but a lot of tweaking is involved.

rgds, sreten.

Thanks Sreten. It is for live use. The subwoofer is a ~ 40 Hz vented alignment, so excursion actually reduces rapidly from 50 Hz down to Fb. I was actually planning to use the "bandpass" mode and set a Q for the DEQ filter that is a close inverted match of the excursion curve down to 50 Hz. I also plan to apply a 48Hz HP filter from 35 Hz to address the excursion issues below Fb. Finally I plan to use the compressor to limit the total power fed to the speaker to 350W.