Transfer Function/Room Boost Calculator? - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

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 6th December 2001, 11:08 AM   #1
diyAudio Member
 
Join Date: Dec 2001
Hello,

Anyone know of a software program or equation that I can use to calculate the transfer function/room boost of low frequncies, with the input being my rooms volume?

Thanks,

Dave
  Reply With Quote
Old 6th December 2001, 11:23 AM   #2
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
if that alone was all you had to worry about it wouldnt be such a problem ..... depending upon the shape, size and density of whatever is in your listening room, the position of the sub/s and many other variables, the figures can vary dramatically.
  Reply With Quote
Old 6th December 2001, 08:13 PM   #3
diyAudio Member
 
Join Date: Dec 2001
Default Re: Transfer Function

For now, I'm just looking figure out the boost on frequency independent of room reflections, modes, etc. I realize that this is a simplified account of response, but I want to, at least, take care of this variable. That way I have made the problem of positioning in the room less of a tradeoff between output and smooth response, even though I will not have entirely eliminated the problem.

Am I making any sense?

Dave
  Reply With Quote
Old 6th December 2001, 08:41 PM   #4
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
The problem is that depending on placement and room shape alone there could be close to no gain, going all the way up to 10-12dB at 20Hz in a very small (car) room.

Room shape is far more important than it's volume. I'm sure someone with more knowledge of room interactions could suggest a room shape with a small volume that offered very little gain, and a room with much larger volume that offered a huge amount of gain.

You could always measure your room's transfer function. Details on how to do this in a car (it should be rather similar in a room) are available at http://www.diysubwoofers.org/projects/cartf/

In my qualitative experience, room gain isn't nearly as high as most suggest it is unless you consider corner placements.
  Reply With Quote
Old 6th December 2001, 09:24 PM   #5
jteef is offline jteef  United States
diyAudio Member
 
Join Date: Feb 2001
Location: Ogden, UT
Send a message via AIM to jteef
You can measure your transfer function pretty easily using a cheap radio shack SPL meter and an existing sealed driver that is large enough to produce SPLs above ambient in a relatively anechoic enviornment (the middle of your back yard for example?) in the lower frequencies of interest.

jt

  Reply With Quote
Old 6th December 2001, 09:43 PM   #6
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
Quote:
Originally posted by jteef
You can measure your transfer function pretty easily using a cheap radio shack SPL meter and an existing sealed driver that is large enough to produce SPLs above ambient in a relatively anechoic enviornment (the middle of your back yard for example?) in the lower frequencies of interest.

jt
That is such a great idea I just tested out my new sealed Tempest subwoofer driven with 500W in my back yard. My neighbours complained so I came inside. It is definitely "above ambient" at 20Hz.
And it conforms almost exactly to the WinISD simulation. Slightly deeper response, actually. Must be the extra stuffing.
  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
transfer function jenks Solid State 31 24th April 2008 08:28 PM
Sound card transfer function NIC1138 Digital Source 9 15th July 2007 12:15 AM
Estimating amplifier transfer function...? Limhes Solid State 3 26th April 2007 05:17 AM
Transfer Function jclouse Multi-Way 22 1st July 2006 01:19 PM
Transfer function of closed box cm961 Multi-Way 1 31st August 2004 06:42 PM


New To Site? Need Help?

All times are GMT. The time now is 11:43 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