How to boost certain frequencies? - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 11th February 2013, 07:41 AM   #1
diyAudio Member
 
Join Date: May 2011
Default How to boost certain frequencies?

Is there a way to boost certain frequencies via circuitry? I am trying to boost frequencies as low as 5hz or lower if I can, is there a way to do this? What I am trying to do is apply a house curve down to single digits if I can.

Cheers

Last edited by JapanDave; 11th February 2013 at 07:49 AM.
  Reply With Quote
Old 11th February 2013, 10:20 AM   #2
OllBoll is offline OllBoll  Sweden
diyAudio Member
 
Join Date: Nov 2010
Either you read up on analogue circuitry or easier would probably be to do it through DSP. However, since you want to EQ so low you would need to have very high arithmetic precision on the DSP.
  Reply With Quote
Old 11th February 2013, 12:11 PM   #3
diyAudio Member
 
dimkasta's Avatar
 
Join Date: May 2010
Location: Athens
What are you trying to achieve? Boosting such low frequencies could also boost offsets and create problems with DC if the cutting slope is not steep enough.
  Reply With Quote
Old 11th February 2013, 12:14 PM   #4
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
 
Join Date: Nov 2005
there are special labs with such systems
very big, and complicated

used for different studies
basicly I think test objects or persons are literally placed inside a big speaker, which also happens to be a room

funny to see a hell lot of woofers moving, but nothing else happens
  Reply With Quote
Old 11th February 2013, 12:24 PM   #5
diyAudio Member
 
Join Date: Oct 2011
Location: Center of the Map
FYI - I build portable powered speakers, some of which are configured for studio type powered monitors. I run my input into an combination active opamp filter that shaves off everything below 40 hz to eliminate the sub-harmonics and everything above 30 khz. The next stage consists of several opamp buffers to break out the frequencies to specific opamp filters and then to the amps, some chip-amps, and the proper speaker(s): tweeter, mid-range, and woofer. The point - I have tested this arrangement with and without the sub-harmonic filter and you can HEAR the difference when you have the filter in place. Amplifying anything below a Bass Guitar, 40 Hz, is bad news sonically. When I apply the 40 Hz High Pass Filter, the Bass sounds even better and crisp; a lesson learned.

Now to dive deeper into your question? Yes. There are numerous opamp audio filter calculators and tutorials on the Net that discuss "active opamp audio filtering." Elliot Sound Products (ESP) has some great schooling, example, and projects that will help you in your quest. Personally, I like his site a great deal.
  Reply With Quote
Old 11th February 2013, 03:20 PM   #6
diyAudio Member
 
Join Date: Apr 2009
Dave,

I would not use parametric eq below 20Hz anyway. Not really a good idea. Use a shelf boost with a knee in the 15-20Hz range if you must. Basically an LT type filter. You must be very careful messing around with EQ that low or amps and speakers will get damaged. Most any unit with a shelf filter can produce this type of boost. You could always get a Marchand Bassis
  Reply With Quote
Old 11th February 2013, 08:30 PM   #7
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
Blog Entries: 8
Any amp worth it's salt will stand it.

I'd expect bass drivers to run out of headroom very very quickly, even something really big.

Mark, that's certainly an interesting opinion WRT bass reproduction. What're your thoughts on reproducing a double bass, where the lowest string is tuned down at 31Hz?

Chris
  Reply With Quote
Old 11th February 2013, 10:29 PM   #8
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
5Hz? Let me give you a hint. There is a reason a standard 33 band PA eq does not go that low. You should not. If you must prove why to yourself, You probably need to build a box as even the eq boxes you could modify have the DC servo higher that that or if not servo, will have blocking caps at much higher cutoff. For a house sound system, 25Hz HP is far more reasonable. If you succeed, about all you will do is find out that subsonics give people a horrible headache and can sometimes cause issues with bladder or bowel control.
  Reply With Quote
Old 11th February 2013, 11:37 PM   #9
diyAudio Member
 
Join Date: May 2011
Quote:
Originally Posted by dimkasta View Post
What are you trying to achieve? Boosting such low frequencies could also boost offsets and create problems with DC if the cutting slope is not steep enough.
I am trying to get a house curve that does not stop @20hz. At the moment I can get a nice house curve down to about 18hz and after that it goes flat due to my receiver's EQ only applying filters down to 20hz.

Quote:
Originally Posted by Josh Ricci View Post
Dave,

I would not use parametric eq below 20Hz anyway. Not really a good idea. Use a shelf boost with a knee in the 15-20Hz range if you must. Basically an LT type filter. You must be very careful messing around with EQ that low or amps and speakers will get damaged. Most any unit with a shelf filter can produce this type of boost. You could always get a Marchand Bassis
How would I go about doing a shelf boost at those frequencies? And what is a Marchand Bassis? (Off to see what google has to say)

Quote:
Originally Posted by tvrgeek View Post
5Hz? Let me give you a hint. There is a reason a standard 33 band PA eq does not go that low. You should not. If you must prove why to yourself, You probably need to build a box as even the eq boxes you could modify have the DC servo higher that that or if not servo, will have blocking caps at much higher cutoff. For a house sound system, 25Hz HP is far more reasonable. If you succeed, about all you will do is find out that subsonics give people a horrible headache and can sometimes cause issues with bladder or bowel control.
Prolonged subsonics may give 'some' people a headach, but bowel control? I was under the impression that that was an old wives tail???
  Reply With Quote
Old 11th February 2013, 11:38 PM   #10
diyAudio Member
 
Join Date: May 2011
Quote:
Originally Posted by Mark Rakemaker View Post
Now to dive deeper into your question? Yes. There are numerous opamp audio filter calculators and tutorials on the Net that discuss "active opamp audio filtering." Elliot Sound Products (ESP) has some great schooling, example, and projects that will help you in your quest. Personally, I like his site a great deal.
Thanks , I will check it out.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
no high frequencies bmmc Car Audio 5 30th March 2012 07:02 PM
[enquiry] Treble Boost/High frequency Boost circuitry elnino86 Parts 2 18th December 2008 12:33 PM
Help with 3-way crossover frequencies grjr Multi-Way 18 28th October 2008 07:26 PM
Test frequencies Christian Everything Else 1 24th March 2002 12:19 AM
Frequencies for EQ? Lisandro_P Solid State 5 12th November 2001 07:16 AM


New To Site? Need Help?

All times are GMT. The time now is 06:24 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2