Differents results from differents simulation sofware - 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 7th December 2012, 09:44 AM   #1
sebDIY is offline sebDIY  Belgium
diyAudio Member
 
Join Date: Oct 2011
Default Differents results from differents simulation sofware

Hi, I'm trying to understand, for my knowledge, how to do bass reflex sim. I've find formulas here: The Subwoofer DIY Page - Ported Systems: Frequency Response Calculations (Thank you Brian to share this)

I've put formulas into Excel and compare with others software. Excel gives me same results as BassBox PRO and WinISD. But if I compare to Hornresp and Akabak, I've seen some differences, sensitivity and fréquency response. Akabak and Hornresp gives similar results.

Here copy screen of Hornresp, Excel, WinISD. I've made perfect flat curve in Hornesp with Beyma Driver 18P1200Nd, ( http://profesional.beyma.com/ingles/pdf/18P1200NdN.pdf ) Vb 110 liters, Fb 50.14Hz, then same sim in WinISD and Excel (with Ql=7):

Hornresp sim:
Click the image to open in full size.
Click the image to open in full size.


Excel:
Click the image to open in full size.


WinISD:
Click the image to open in full size.

As you can see, differences in WinISD and Excel are : little bump , F3 is higher, sensitivity is lower by 3.5dB.

So, Which software say the truth?

Last edited by sebDIY; 7th December 2012 at 10:57 AM. Reason: Error
  Reply With Quote
Old 7th December 2012, 10:21 AM   #2
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Quote:
Originally Posted by sebDIY View Post
Hi, I'm trying to understand, for my knowledge, how to do bass reflex sim. I've find formulas here: The Subwoofer DIY Page - Ported Systems: Frequency Response Calculations (Thank you Brian to share this)

I've put formulas into Excel and compare with others software. Excel gives me same results as BassBox PRO and WinISD. But if I compare to Hornresp and Akabak, I've seen some differences, sensitivity and fréquency response. Akabak and Hornresp gives similar results.

Here copy screen of Hornresp, Excel, WinISD. I've made perfect flat curve in Hornesp with Beyma Driver 18P1200Nd, ( http://profesional.beyma.com/ingles/pdf/18P1200NdN.pdf ) Vb 100 liters, Fb 50.88Hz, then same sim in WinISD and Excel (with Ql=7):

Hornresp sim:
Click the image to open in full size.



Excel:
Click the image to open in full size.


WinISD:
Click the image to open in full size.

As you can see, differences in WinISD and Excel are : little bump , F3 is higher, sensitivity is lower by 3.5dB.

So, Which software say the truth?
Hi sebDIY,

Why not post your input screens. the only way for other DIY-members to find out why there are differences.

b
  Reply With Quote
Old 7th December 2012, 11:05 AM   #3
sebDIY is offline sebDIY  Belgium
diyAudio Member
 
Join Date: Oct 2011
Hi Bjorno, I have include the input screen of Hornresp in my first post, and repost all the frequency response, there was a little error, but nothing change: Akabak and Hornresp have the same flat response (or very similar), same F3, but WinISD, excel formula, and even Bassbox show little bump, higher F3, lower sensitivity.
  Reply With Quote
Old 7th December 2012, 07:18 PM   #4
OMNIFEX is offline OMNIFEX  Jamaica
diyAudio Member
 
OMNIFEX's Avatar
 
Join Date: Mar 2003
Location: Locked Up In The Amp Rack
Hi.

I would put more trust in software designed to create reflex cabinets if that is the goal than, software designed to create horns. Upon looking at the parameters required for horn response to draw to its conclusion, it is evident that it is not using the traditional parameters used to create a reflex cabinet.
__________________
OMNIFEX
  Reply With Quote
Old 7th December 2012, 10:24 PM   #5
Djim is offline Djim  Netherlands
diyAudio Member
 
Join Date: Dec 2009
Location: 'Ollanda
Hi sebDIY,

Indeed, it would be much easier if you showed all input pages.
Maybe the difference in output level is because winISD uses Watts and HornResp/Akabak uses Voltage. The difference in response may be the result of the port volume.
  Reply With Quote
Old 8th December 2012, 04:50 AM   #6
sebDIY is offline sebDIY  Belgium
diyAudio Member
 
Join Date: Oct 2011
Hi Djim, it's very simple and quick to makes a comparison between Hornresp and WinIsd, even with UNIBOX which gives similars results as WinISD and BassBox. So everybody could see the problem by himself, it will be easier.

I've tried to use SPL voltage in excel. It's improves the comparison a little, but not totally and not for all drivers.

I don't see why software like Hornresp or Akabak couldn't do bassreflex sims.

If David McBean read this thread and can tell us if his software can do Bassreflex sims with accuracy or not? I will be interesting also to know why these differences.
  Reply With Quote
Old 8th December 2012, 07:15 AM   #7
diyAudio Member
 
Join Date: Jun 2007
Quote:
Originally Posted by OMNIFEX View Post
I would put more trust in software designed to create reflex cabinets if that is the goal than, software designed to create horns.
Hi OMNIFEX,

Hornresp uses a more sophisticated bass-reflex simulation model than WinISD.

While I don't know for sure, I would expect that in theory the Hornresp predictions should be the more accurate.

AkAbak and Hornresp use essentially the same model.

Kind regards,

David
__________________
www.hornresp.net
  Reply With Quote
Old 8th December 2012, 07:19 AM   #8
diyAudio Member
 
Join Date: Jun 2007
Quote:
Originally Posted by sebDIY View Post
If David McBean read this thread and can tell us if his software can do Bassreflex sims with accuracy or not?
Hi sebDIY,

See my post #7 above.

Kind regards,

David
__________________
www.hornresp.net
  Reply With Quote
Old 9th December 2012, 05:33 PM   #9
OMNIFEX is offline OMNIFEX  Jamaica
diyAudio Member
 
OMNIFEX's Avatar
 
Join Date: Mar 2003
Location: Locked Up In The Amp Rack
Quote:
Originally Posted by David McBean View Post
Hi OMNIFEX,

Hornresp uses a more sophisticated bass-reflex simulation model than WinISD.

While I don't know for sure, I would expect that in theory the Hornresp predictions should be the more accurate.

AkAbak and Hornresp use essentially the same model.

Kind regards,

David
Hi David.

I have a lot of experience with Eminence Designer that is a light version of Harristech’s Bass Box pro in which, sebDIY mentioned. I’ve compared Bass Box Pro to Eminence designer and the results are exactly the same.

The problem with Horn Response is that it does not offer the traditional parameters used for designing a reflex cabinet. If I need to convert the parameters in Eminence Designer in order for Horn Response to recognise the figures it is requesting, why would I bother with Horn Response to design a reflex cabinet?

Possibly, it would be better for Horn Response to have compatible parameters that reflect what manufactures offer when they sell raw drivers if Horn Response is looking to expand into reflex designs.

Cheers!
__________________
OMNIFEX
  Reply With Quote
Old 10th December 2012, 06:39 AM   #10
diyAudio Member
 
Join Date: Jan 2005
Location: Rotterdam, NL
Quote:
it does not offer the traditional parameters used for designing a reflex cabinet
Which are?

Best regards Johan
__________________
Impossibilities we do immediatly, miracles take slightly longer.
  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
LTSpice FFT simulation settings and inconsistent results. Mooly Software Tools 106 25th June 2013 02:14 AM
Differents betw. X1_X2 \Y1_Y2 caps Stream Chip Amps 5 9th March 2009 08:24 PM
Simulation Results: Dayton RS180 / Seas 27TBFC 2-way Bookshelf Jay_WJ Multi-Way 97 19th June 2007 11:05 AM
Differents Of the "DVR134" & "BOSOZ" thomasfw Pass Labs 19 6th April 2005 06:17 PM


New To Site? Need Help?

All times are GMT. The time now is 02:49 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