Planar vs. cone dipole LF

amt · 5th March 2004, 04:52 PM

I own a pair of Magnepans and also several experimental dipole speakers (Orion type and various fullrangers) and was wondering how it is that the cone dipoles need so much eq manipulation while the Maggies produce pretty flatly down to 40hz with no eq. Is it just a matter of the panel having a huge Sd compared to 2 - 4 12'' drivers, or are there more complex physics issues involved?

amt

megajocke · 5th March 2004, 07:14 PM

The bass EQ can be done by having a high Q. The bass hump conunteracts the dipole rolloff. I guess these speakers do something like that.

amt · 5th March 2004, 07:57 PM

That would make sense. I dont know what the Q of a mylar membrane is or how its measured but that might explain the good LF performance.

amt

Roscoe Primrose · 5th March 2004, 08:12 PM

Q may not be the only reason, how many of your cone dipole woofers have baffles as large as a typical Maggie? You could easily put 4 15" woofers on a flat baffle the size of an MG2...

BTW, my 2x15" Phoenix-style dipole woofers are fairly flat into the high 30s without any EQ...

Roscoe's Dipoles

Peace

amt · 5th March 2004, 08:56 PM

No eq? Are those the Pyle drivers used by chops? Im using Pioneers and older CV drivers and both need at least +6 boost. How efficient do you guess they are?

amt

Roscoe Primrose · 5th March 2004, 09:21 PM

Quote:

Originally posted by amt
No eq? Are those the Pyle drivers used by chops? Im using Pioneers and older CV drivers and both need at least +6 boost. How efficient do you guess they are?

amt

Yeah, same drivers. I'd guess about 92dB/W/m, but I'm running a 250W plate amp for them, so I'm not about to run out of power before I run out of Xmax... I plan to add some boost at about 25-28Hz so I can get another half an octave, I just havn't gotten around to it yet

Peace

sreten · 5th March 2004, 11:21 PM

the simple answer is bass planar drivers are arranged to have a Q
of between 2 and 3 and tuned to an Fs related to the effective
baffle width such that with voltage drive response is flat or to
target (fairly near flat) down to Fs.

Consequently the panel Fs is always near to the low frequency limit.

sreten.

5th March 2004, 04:52 PM	#1
amt diyAudio Member Join Date: Feb 2003 Location: oregon	Planar vs. cone dipole LF I own a pair of Magnepans and also several experimental dipole speakers (Orion type and various fullrangers) and was wondering how it is that the cone dipoles need so much eq manipulation while the Maggies produce pretty flatly down to 40hz with no eq. Is it just a matter of the panel having a huge Sd compared to 2 - 4 12'' drivers, or are there more complex physics issues involved? amt

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5th March 2004, 07:14 PM	#2
megajocke diyAudio Member Join Date: Jan 2003	The bass EQ can be done by having a high Q. The bass hump conunteracts the dipole rolloff. I guess these speakers do something like that.

5th March 2004, 07:57 PM	#3
amt diyAudio Member Join Date: Feb 2003 Location: oregon	That would make sense. I dont know what the Q of a mylar membrane is or how its measured but that might explain the good LF performance. amt

5th March 2004, 08:12 PM	#4
Roscoe Primrose diyAudio Member Join Date: Jan 2004 Location: Virginia, USA	Q may not be the only reason, how many of your cone dipole woofers have baffles as large as a typical Maggie? You could easily put 4 15" woofers on a flat baffle the size of an MG2... BTW, my 2x15" Phoenix-style dipole woofers are fairly flat into the high 30s without any EQ... Roscoe's Dipoles Peace

5th March 2004, 08:56 PM	#5
amt diyAudio Member Join Date: Feb 2003 Location: oregon	No eq? Are those the Pyle drivers used by chops? Im using Pioneers and older CV drivers and both need at least +6 boost. How efficient do you guess they are? amt

5th March 2004, 11:21 PM	#7
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	the simple answer is bass planar drivers are arranged to have a Q of between 2 and 3 and tuned to an Fs related to the effective baffle width such that with voltage drive response is flat or to target (fairly near flat) down to Fs. Consequently the panel Fs is always near to the low frequency limit. sreten.