Keele, D. (2004) "Maximum efficiency of compression drivers"

svenr · 25th October 2007, 11:31 AM

Hi folks,

Don Keele's probably well known article examines the relationship between driver parameters, nominal and true efficiency for compression driver design. It can be found here:

http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(2004-10%20AES%20Preprint)%20-%20Maximum%20Efficiency%20of%20Compression%20Drive rs.pdf

It's interesting to observe that Keele stops his talk when it comes to the interesting parts.

When looking at section 6.4.2 equation (40) of the paper, Keele derives the nominal efficiency of a compression driver loaded by an infinite tube while neglecting the influence of voice coil inductance and front chamber compliance. Equation (40) is than simplified by introducing normalization variables and given as equation (41).

When calculating both equations from the same set of given variables I get (surely caused by my math incapability) differing results. Equation (40) involves 5 independent parameters (R1, R2, R3, L2 and C2) as well as the variable w. But the simplified equation (41) shows only 3 independent and 1 interdependent parameter (plus the normalized variable wn). Equation (40) is strongly influenced by inductance L2 representing system compliance, while equation (41) is not influenced by normalization variable wo representing L2.

I've prepared a little spreadsheet (with most of the equations probably transcribed incorrectly):

www.geocities.com/srechenberger

I would appreciate if you could help me out with this; I'm kind of confused...

Greetz
Sven

GM · 25th October 2007, 03:33 PM

Greets!

Wish I could, but my higher math skills are mostly non-existant, so about all I can help with is a valid link: http://www.xlrtechs.com/dbkeele.com/...%20Drivers.pdf

GM

svenr · 28th October 2007, 03:14 AM

Hi folks,

anybody must be able to give me a hint where the problem is within the transformation...

Cheers

GM · 28th October 2007, 02:03 PM

Greets!

There are, but very few of us on this forum have any interest in compression horns, so try these instead:
http://audioheritage.csdco.com/vbulletin/
http://www.audioasylum.com/forums/hug/bbs.html
http://www.audioroundtable.com/HighEfficiencySpeakers/

GM

25th October 2007, 11:31 AM	#1
svenr diyAudio Member Join Date: Oct 2007	Keele, D. (2004) "Maximum efficiency of compression drivers" Hi folks, Don Keele's probably well known article examines the relationship between driver parameters, nominal and true efficiency for compression driver design. It can be found here: http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(2004-10%20AES%20Preprint)%20-%20Maximum%20Efficiency%20of%20Compression%20Drive rs.pdf It's interesting to observe that Keele stops his talk when it comes to the interesting parts. When looking at section 6.4.2 equation (40) of the paper, Keele derives the nominal efficiency of a compression driver loaded by an infinite tube while neglecting the influence of voice coil inductance and front chamber compliance. Equation (40) is than simplified by introducing normalization variables and given as equation (41). When calculating both equations from the same set of given variables I get (surely caused by my math incapability) differing results. Equation (40) involves 5 independent parameters (R1, R2, R3, L2 and C2) as well as the variable w. But the simplified equation (41) shows only 3 independent and 1 interdependent parameter (plus the normalized variable wn). Equation (40) is strongly influenced by inductance L2 representing system compliance, while equation (41) is not influenced by normalization variable wo representing L2. I've prepared a little spreadsheet (with most of the equations probably transcribed incorrectly): www.geocities.com/srechenberger I would appreciate if you could help me out with this; I'm kind of confused... Greetz Sven

25th October 2007, 03:33 PM	#2
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Greets! Wish I could, but my higher math skills are mostly non-existant, so about all I can help with is a valid link: http://www.xlrtechs.com/dbkeele.com/...%20Drivers.pdf GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

28th October 2007, 02:03 PM	#4
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Greets! There are, but very few of us on this forum have any interest in compression horns, so try these instead: http://audioheritage.csdco.com/vbulletin/ http://www.audioasylum.com/forums/hug/bbs.html http://www.audioroundtable.com/HighEfficiencySpeakers/ GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
1" compression drivers with 2" diaphragms	454Casull	Multi-Way	24	9th August 2009 04:19 PM
2" affordable compression drivers	usa_satriani	Multi-Way	107	16th November 2008 08:21 AM
21" Bass Drivers and Beyma Compression Drivers	Magnetar	Swap Meet	0	19th November 2006 02:42 AM
Good 2" compression drivers?	imix500	Multi-Way	12	6th July 2005 06:01 PM


	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

28th October 2007, 03:14 AM	#3
svenr diyAudio Member Join Date: Oct 2007	Hi folks, anybody must be able to give me a hint where the problem is within the transformation... Cheers

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read