Two new 18" Offset Horns

FreakyShotGlass · 21st October 2010, 12:30 AM

Threw together two new horn designs for the P.Audio E18ELF driver. One is ~1000L and gets around 104 dB/2.83V/m and the other is just over 550L and gets 102 dB/2.83V/m.

jbell · 23rd October 2010, 02:31 PM

Over 10:1 compression on an 18" driver? wow, I've gone against the conventional wisdom and have used up to 8:1 on an 8" driver, but never an 18.....

Planning on a cone shredding party?

chris661 · 23rd October 2010, 04:02 PM

Interesting you should say that.

I'm not an expert on this, but, at port tuning, a driver almost stops moving (need to shove a lot of power in to get it moving the same amount). 18" speakers get used in ported cabs all the time, and I've never heard of one shredding.

soho54 · 23rd October 2010, 05:49 PM

That is not the same thing.

epa · 23rd October 2010, 09:13 PM

in this case (offset driver) isn't s2 the compression area?

Top Shelf · 09:55 PM

Take this high comp ratio scenario and equate it to a 4th order( rear sealed) bandpass box. I see many 12" bandpass boxes built with a 4" port on the front chamber( 6 to 1 ratio). Is the reason the cone doesn't break because of the increased box volume(air compliance) in front of the driver?,as opposed to a smaller compression(front) chamber used on a tapped horn. Or is this still not the same situation?

soho54 · 24th October 2010, 05:48 AM

Quote:

Originally Posted by epa

in this case (offset driver) isn't s2 the compression area?

Yes.

David_Web · 24th October 2010, 07:35 AM

In a BR or BP the pressure have time to equalize and avoid high pressure bumps and vibrations.

In a horn with high CR you can get pockets with high pressure that will flex the cone, uneven loading due to taper will make it worse, this can make it rip. HOM is probably bad for it as well due to it's chessboard standing pattern. Water is a factor that will make it a lot easier to break.
Sort of like an aluminum can. You can stand on it without a problem. But as soon as it flexes or get a ding it will rip and collapse.

That's my theory at least.

FreakyShotGlass · 24th October 2010, 07:46 AM

Quote:

Originally Posted by jbell

Over 10:1 compression on an 18" driver? wow, I've gone against the conventional wisdom and have used up to 8:1 on an 8" driver, but never an 18.....

Planning on a cone shredding party?

Compression ratio is only 2:1, so not too worried about any shredding.
Through together some new designs for an Ande LB1560 15" driver to be used in banks of 4.

Volume of 469L all up.

23rd October 2010, 04:02 PM	#3
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	Interesting you should say that. I'm not an expert on this, but, at port tuning, a driver almost stops moving (need to shove a lot of power in to get it moving the same amount). 18" speakers get used in ported cabs all the time, and I've never heard of one shredding. __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

23rd October 2010, 09:41 PM	#6
Top Shelf diyAudio Member Join Date: Apr 2010 Location: Midland, Ontario	Take this high comp ratio scenario and equate it to a 4th order( rear sealed) bandpass box. I see many 12" bandpass boxes built with a 4" port on the front chamber( 6 to 1 ratio). Is the reason the cone doesn't break because of the increased box volume(air compliance) in front of the driver?,as opposed to a smaller compression(front) chamber used on a tapped horn. Or is this still not the same situation? __________________ JEREMY M_________________________________ I like it loud, BUT NOT TOO LOUD!.... Hey do you hear that high pitched ringing sound ? Last edited by Top Shelf; 23rd October 2010 at 09:55 PM. Reason: more

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23rd October 2010, 02:31 PM	#2
jbell diyAudio Member Join Date: Apr 2003 Location: .	Over 10:1 compression on an 18" driver? wow, I've gone against the conventional wisdom and have used up to 8:1 on an 8" driver, but never an 18..... Planning on a cone shredding party?

23rd October 2010, 05:49 PM	#4
soho54 diyAudio Member Join Date: Nov 2005 Location: Georgia	That is not the same thing.

23rd October 2010, 09:13 PM	#5
epa diyAudio Member Join Date: Apr 2010 Location: amsterdam	in this case (offset driver) isn't s2 the compression area?

24th October 2010, 07:35 AM	#8
David_Web diyAudio Member Join Date: Sep 2008	In a BR or BP the pressure have time to equalize and avoid high pressure bumps and vibrations. In a horn with high CR you can get pockets with high pressure that will flex the cone, uneven loading due to taper will make it worse, this can make it rip. HOM is probably bad for it as well due to it's chessboard standing pattern. Water is a factor that will make it a lot easier to break. Sort of like an aluminum can. You can stand on it without a problem. But as soon as it flexes or get a ding it will rip and collapse. That's my theory at least.

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