Parametric EQ for subwoofer?

Elbert · 5th February 2012, 01:29 PM

Hi!

In order to manage some room-modes for my dual 15" subwoofer set-up, I'd like to build a parametric EQ with sweep from 30-80 Hz.

Does anybody have a suggestion for a circuit or know where I could find one?

Elbert · 11th February 2012, 05:09 PM

Bump!

Keep browsing this forum and the web, but can't find anything...

deduikertjes · 25th February 2012, 07:10 PM

Look at Rod Elliot's site.
There you'll find what you need.

Marco

Elbert · 25th February 2012, 08:05 PM

Thanks for the tip Marco!

I've allready looked through Elliot's and the 5-band subwoofer equaliser looked interresting...

However, I have in the mean time found a circuit for a full parametric EQ, which I'm now in the process of modifying and implementing. Posted some stuff on this on a separate thread.

Chris Hornbeck · 25th February 2012, 08:16 PM

I hope you're not too disappointed with the results. Equalizers are a frequency domain solution to a time domain problem (room modes). Hope springs eternal, but many are disappointed without understanding why.

All good fortune,
Chris

Elbert · 25th February 2012, 08:27 PM

You are in deed right, the equalizer will not correct the room modes causing the problems, but reducing the energy at the "offending" frequencies is the next best thing I can do.

Chris Hornbeck · 25th February 2012, 08:30 PM

If you put your measuring microphone right up near the woofers you can start with a flat magnitude response and adjust from there. This will be better than most of us have, fersure.

All good fortune,
Chris

Elbert · 08:47 PM

Yes, A correct starting point is a good idea, measured nearfield/ gated my system is pretty much flat down to 25-30 Hz. In my listening position, there is however a hump of about +6 db in the 40-60 Hz range, which tends to make certain recordings a bit boomy. I anticipate much would be improved by doing some EQ'ing in this area with the help of measurements and critical listening.

sreten · 25th February 2012, 09:04 PM

Quote:

Originally Posted by Chris Hornbeck

I hope you're not too disappointed with the results. Equalizers are a
frequency domain solution to a time domain problem (room modes).
Hope springs eternal, but many are disappointed without understanding why.

All good fortune,
Chris

Hi,

Not really, room modes cause frequency and time domain issues.

The frequency and time domain are interchangeable, and
improving the frequency domain, the frequency response,
will also improve the time domain, the transient response.

rgds, sreten.

tvrgeek · 26th February 2012, 11:37 AM

I found it best to work with bass traps first. A bit of creativity one can actually do such things and still fall under the WAF. I went through a lot of effort with my DCX and an old Yamahamer 1/3 octave graphical phase distortion generator and found nice measurements really did not do much for the overall clarity and musicality. A stack of insulation rolls in the corner did. Using a sweep generator to find a few previously unknown resonators and solve them also helped. So, fix what you can mechanically, then hit it with EQ. If you are using more than one sub, just moving them around to make wherever the humps happen not be your listening spot can sometimes work.

The best bass I ever had was in a mobile home as the walls were basically transparent. No modes. Unforgivably, everyone in the park could enjoy it too.

5th February 2012, 01:29 PM	#1
Elbert diyAudio Member Join Date: Mar 2008	Parametric EQ for subwoofer? Hi! In order to manage some room-modes for my dual 15" subwoofer set-up, I'd like to build a parametric EQ with sweep from 30-80 Hz. Does anybody have a suggestion for a circuit or know where I could find one?

25th February 2012, 08:39 PM	#8
Elbert diyAudio Member Join Date: Mar 2008	Yes, A correct starting point is a good idea, measured nearfield/ gated my system is pretty much flat down to 25-30 Hz. In my listening position, there is however a hump of about +6 db in the 40-60 Hz range, which tends to make certain recordings a bit boomy. I anticipate much would be improved by doing some EQ'ing in this area with the help of measurements and critical listening. Last edited by Elbert; 25th February 2012 at 08:47 PM.

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11th February 2012, 05:09 PM	#2
Elbert diyAudio Member Join Date: Mar 2008	Bump! Keep browsing this forum and the web, but can't find anything...

25th February 2012, 07:10 PM	#3
deduikertjes diyAudio Member Join Date: Aug 2005	Look at Rod Elliot's site. There you'll find what you need. Marco

25th February 2012, 08:05 PM	#4
Elbert diyAudio Member Join Date: Mar 2008	Thanks for the tip Marco! I've allready looked through Elliot's and the 5-band subwoofer equaliser looked interresting... However, I have in the mean time found a circuit for a full parametric EQ, which I'm now in the process of modifying and implementing. Posted some stuff on this on a separate thread.

25th February 2012, 08:16 PM	#5
Chris Hornbeck diyAudio Member Join Date: May 2011 Location: Little Rock	I hope you're not too disappointed with the results. Equalizers are a frequency domain solution to a time domain problem (room modes). Hope springs eternal, but many are disappointed without understanding why. All good fortune, Chris

25th February 2012, 08:27 PM	#6
Elbert diyAudio Member Join Date: Mar 2008	You are in deed right, the equalizer will not correct the room modes causing the problems, but reducing the energy at the "offending" frequencies is the next best thing I can do.

25th February 2012, 08:30 PM	#7
Chris Hornbeck diyAudio Member Join Date: May 2011 Location: Little Rock	If you put your measuring microphone right up near the woofers you can start with a flat magnitude response and adjust from there. This will be better than most of us have, fersure. All good fortune, Chris

26th February 2012, 11:37 AM	#10
tvrgeek diyAudio Member Join Date: Dec 2009 Location: Md	I found it best to work with bass traps first. A bit of creativity one can actually do such things and still fall under the WAF. I went through a lot of effort with my DCX and an old Yamahamer 1/3 octave graphical phase distortion generator and found nice measurements really did not do much for the overall clarity and musicality. A stack of insulation rolls in the corner did. Using a sweep generator to find a few previously unknown resonators and solve them also helped. So, fix what you can mechanically, then hit it with EQ. If you are using more than one sub, just moving them around to make wherever the humps happen not be your listening spot can sometimes work. The best bass I ever had was in a mobile home as the walls were basically transparent. No modes. Unforgivably, everyone in the park could enjoy it too.

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