Another PR170M0/Waveguide experiment

AJ · 27th November 2007, 05:58 AM

I've been wanting to experiment with CD/waveguide combinations for awhile now, and I've been wanting to hear a pair of PR170M0s per side as well. So, on the way to an OB system, I put together some modular components to hear both. The 170s are in a slightly overdamped (Qtc ~.65) sealed box with false walls filled with 45 pounds of clumping kitty litter. I couldn't find any Playsand locally and the basic construction sand had iron in it when I dragged a magnet thru it. I just filled in around the connections to the binding posts, so I kinda thought iron might be problematic. The waveguide is a DDS ENG90 and the comp driver is a B&C DE250 (8ohm).

I used a bi-wire set of binding posts and a coupla short jumpers for the Audax drivers so I could quickly change from parallel to series and to make it easier to insert passive components if needed. The system is all active 3-way, but I usually end up adding passive baffle step or something to the mess. In this case, it was a smart move, as the double Audax doesn't act like a simply more efficient single. There's a definite increase in midrange energy (maybe 500hz to 1khz?) that doesn't seem to be proportional to the rest and I'll probably need to roll one of them off to get some better balance. I ran them series, parallel, and one at a time, and parallel is most to my liking if I can drain off a little of the extra midrange. Overall, the liveliness is pretty addictive.

The star of the show is the CD/waveguide - I really wish I would've looked into these earlier. I've been very surprised at the quality of the combination. Extremely clear and smooth presentation with no hint of running out of steam at any volume level. The headroom from these things is just plain relaxing and un-constipated...like I've been living in an audio coffin all my life and I can finally breathe.

I'm still waiting for a set of XT1086 WGs and a pair of BMS 4540 drivers so I'll have something else to compare to, but in the meantime I'll do some tweaking on this setup to try and get a better understanding of what's going on. No measurements of anything yet, but that'll be coming soon.

Anyway, this was a very cool experiment and this type of presentation is probably what I've been looking for all my life. As much as I've tried to resist, I just know I'm gonna end up with horns in here eventually.

Magnetar · 27th November 2007, 06:32 AM

Quote:

Originally posted by AJ

Anyway, this was a very cool experiment and this type of presentation is probably what I've been looking for all my life. As much as I've tried to resist, I just know I'm gonna end up with horns in here eventually.

Horn load the mid and add five or six tens a side for the bass

AJ · 27th November 2007, 06:51 AM

"...add five or six tens a side for the bass."

I hear ya Mike about the bass. These things do fine for a less efficient system, but it was immediately obvious that they're not gonna cut it for this one. I'm a little cramped for space here and the 18s in these boxes do double duty as subs thru lower midrange so they're a nice compromise. I've been mulling over 4-6 12 inchers per side or possibly 4 15s per side for a year now, so that'll probably be the next big build. My biggest problem is that I'm an extension bass junkie - I like it to go to 20hz - and the current boxes do that rather easily. I may need to go 4-way but I don't know where to put dedicated subs.

I'll figure it out if I have to I'm sure.

ttan98 · 27th November 2007, 07:12 AM

AJ,

A few questions please:

1. what model of Audax driver you are using?
2. x-over freq. between waveguide and Audax?
3. what order of filter from 2.?

thanks.

AJ · 27th November 2007, 07:28 AM

ttan98,

1. what model of Audax driver you are using?

They're the PR170M0.

2. x-over freq. between waveguide and Audax?

I haven't settled on the frequency yet. I've been listening to them between 1.2khz and 2khz so far and either the waveguide isn't large enough or the B&C drivers don't like it that low, but 1.2khz sounds worse than 2khz. Keep in mind this is all purely subjective and without taking some realistic measurements, I really don't know what's going on with them yet. My feeling at this point is that 1.5khz is probably a solid number (see #3)

3. what order of filter from 2.?

I'm using an Ashly XR2001 active XO so all I have to work with is LR4. Acoustically of course, it's going to be somewhat different.

ttan98 · 27th November 2007, 10:03 PM

Quote:

Originally posted by AJ
ttan98,

1. what model of Audax driver you are using?

They're the PR170M0.,

How do you find his driver? Magnetar likes it a lot.

2. x-over freq. between waveguide and Audax?

I haven't settled on the frequency yet. I've been listening to them between 1.2khz and 2khz so far and either the waveguide isn't large enough or the B&C drivers don't like it that low, but 1.2khz sounds worse than 2khz. Keep in mind this is all purely subjective and without taking some realistic measurements, I really don't know what's going on with them yet. My feeling at this point is that 1.5khz is probably a solid number (see #3)

It is possible the size of yr waveguide is not large enough for you to run at 1khz? Also can B&C compression driver(CD) capable of operating at 1Khz? Emerald Physics uses a 12" waveguide to operate the CD at 1Khz.
I have heard from others that 1khz is too low to operate a CD eventhough some can handle it. The lower the freq. the wider the dispersion. I suppose the ear is determining factor.

.

SamL · 28th November 2007, 12:39 AM

Quote:

Originally posted by AJ

2. x-over freq. between waveguide and Audax?

I haven't settled on the frequency yet. I've been listening to them between 1.2khz and 2khz so far and either the waveguide isn't large enough or the B&C drivers don't like it that low, but 1.2khz sounds worse than 2khz. Keep in mind this is all purely subjective and without taking some realistic measurements, I really don't know what's going on with them yet. My feeling at this point is that 1.5khz is probably a solid number (see #3)

No expert in this field. What I read from this site, DE250 is recommend to cross around 1.6kHz.
http://www.usspeaker.com/B&C-DE250-1.htm
Maybe Beyma CP380 is a better candidate? It is also a bit more expensive.
http://www.usspeaker.com/beyma%20CP380M-1.htm

btw... really like what you are doing as PR170M0 is what I have in mind. I wish I can start buying and building but too many project to complete.... a fact of life

Have fun

AJ · 28th November 2007, 01:08 AM

"What I read from this site, DE250 is recommend to cross around 1.6kHz."

Right. 1.6khz, 2nd order. I'm doing 4th order @ 1.2khz so my guess is that they'll both be down 12db at 800hz either way. Everyone seems to like that Beyma so maybe I'll give it a shot after I mess around with the BMS and B&C.

"How do you find his driver? Magnetar likes it a lot."

I like it alot too.

boydon_lepasci · 28th November 2007, 01:14 AM

I don't know enough about the two setups to be sure of apples-to-apples, but if yours is comparable to Dr. Geddes I believe the waveguide should allow for a lower XO than mfr spec. It may also require a brick wall HP to cross where phase response is a good match. Can you cascade the Ashly LR4s and just make a single channel to audition? Feel free to ignore my rambling, I just haven't posted for a while so this is pretty superficial.

CLS · 28th November 2007, 01:38 AM

Hi AJ,

I notice there's a WG on the floor in front of the bass cabinet, and it looks like this:

http://www.partsexpress.com/pe/showd...number=270-310

(Dayton has several sizes in this series, 6~12in mouths. )

Is it any good? (or bad, since it's abandoned and put aside)

27th November 2007, 05:58 AM	#1
AJ diyAudio Member Join Date: Aug 2003 Location: Oregon	Another PR170M0/Waveguide experiment I've been wanting to experiment with CD/waveguide combinations for awhile now, and I've been wanting to hear a pair of PR170M0s per side as well. So, on the way to an OB system, I put together some modular components to hear both. The 170s are in a slightly overdamped (Qtc ~.65) sealed box with false walls filled with 45 pounds of clumping kitty litter. I couldn't find any Playsand locally and the basic construction sand had iron in it when I dragged a magnet thru it. I just filled in around the connections to the binding posts, so I kinda thought iron might be problematic. The waveguide is a DDS ENG90 and the comp driver is a B&C DE250 (8ohm). I used a bi-wire set of binding posts and a coupla short jumpers for the Audax drivers so I could quickly change from parallel to series and to make it easier to insert passive components if needed. The system is all active 3-way, but I usually end up adding passive baffle step or something to the mess. In this case, it was a smart move, as the double Audax doesn't act like a simply more efficient single. There's a definite increase in midrange energy (maybe 500hz to 1khz?) that doesn't seem to be proportional to the rest and I'll probably need to roll one of them off to get some better balance. I ran them series, parallel, and one at a time, and parallel is most to my liking if I can drain off a little of the extra midrange. Overall, the liveliness is pretty addictive. The star of the show is the CD/waveguide - I really wish I would've looked into these earlier. I've been very surprised at the quality of the combination. Extremely clear and smooth presentation with no hint of running out of steam at any volume level. The headroom from these things is just plain relaxing and un-constipated...like I've been living in an audio coffin all my life and I can finally breathe. I'm still waiting for a set of XT1086 WGs and a pair of BMS 4540 drivers so I'll have something else to compare to, but in the meantime I'll do some tweaking on this setup to try and get a better understanding of what's going on. No measurements of anything yet, but that'll be coming soon. Anyway, this was a very cool experiment and this type of presentation is probably what I've been looking for all my life. As much as I've tried to resist, I just know I'm gonna end up with horns in here eventually.

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
xt25 in 12in waveguide experiment	MisterTwister	Multi-Way	65	23rd July 2010 06:08 PM
PR170M0 OB dipole x-over points.	AudioGeek	Multi-Way	25	2nd January 2009 04:26 AM
Audax PR170M0 –100 dB or just *94 dB??	rick57	Multi-Way	39	14th May 2006 03:58 AM
WTB: Audax PR170M0 drivers	Saurav	Swap Meet	0	5th April 2004 08:10 PM
Pr170m0	RAYSIMMONS	Multi-Way	4	15th October 2002 08:29 PM

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


	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

27th November 2007, 06:51 AM	#3
AJ diyAudio Member Join Date: Aug 2003 Location: Oregon	"...add five or six tens a side for the bass." I hear ya Mike about the bass. These things do fine for a less efficient system, but it was immediately obvious that they're not gonna cut it for this one. I'm a little cramped for space here and the 18s in these boxes do double duty as subs thru lower midrange so they're a nice compromise. I've been mulling over 4-6 12 inchers per side or possibly 4 15s per side for a year now, so that'll probably be the next big build. My biggest problem is that I'm an extension bass junkie - I like it to go to 20hz - and the current boxes do that rather easily. I may need to go 4-way but I don't know where to put dedicated subs. I'll figure it out if I have to I'm sure.

27th November 2007, 07:12 AM	#4
ttan98 diyAudio Member Join Date: Apr 2006 Location: Melb	AJ, A few questions please: 1. what model of Audax driver you are using? 2. x-over freq. between waveguide and Audax? 3. what order of filter from 2.? thanks.

27th November 2007, 07:28 AM	#5
AJ diyAudio Member Join Date: Aug 2003 Location: Oregon	ttan98, 1. what model of Audax driver you are using? They're the PR170M0. 2. x-over freq. between waveguide and Audax? I haven't settled on the frequency yet. I've been listening to them between 1.2khz and 2khz so far and either the waveguide isn't large enough or the B&C drivers don't like it that low, but 1.2khz sounds worse than 2khz. Keep in mind this is all purely subjective and without taking some realistic measurements, I really don't know what's going on with them yet. My feeling at this point is that 1.5khz is probably a solid number (see #3) 3. what order of filter from 2.? I'm using an Ashly XR2001 active XO so all I have to work with is LR4. Acoustically of course, it's going to be somewhat different.

28th November 2007, 01:08 AM	#8
AJ diyAudio Member Join Date: Aug 2003 Location: Oregon	"What I read from this site, DE250 is recommend to cross around 1.6kHz." Right. 1.6khz, 2nd order. I'm doing 4th order @ 1.2khz so my guess is that they'll both be down 12db at 800hz either way. Everyone seems to like that Beyma so maybe I'll give it a shot after I mess around with the BMS and B&C. "How do you find his driver? Magnetar likes it a lot." I like it alot too.

28th November 2007, 01:14 AM	#9
boydon_lepasci diyAudio Member Join Date: Apr 2005 Location: Salt Lake	I don't know enough about the two setups to be sure of apples-to-apples, but if yours is comparable to Dr. Geddes I believe the waveguide should allow for a lower XO than mfr spec. It may also require a brick wall HP to cross where phase response is a good match. Can you cascade the Ashly LR4s and just make a single channel to audition? Feel free to ignore my rambling, I just haven't posted for a while so this is pretty superficial.

28th November 2007, 01:38 AM	#10
CLS diyAudio Member Join Date: Jun 2005 Location: Taiwan	Hi AJ, I notice there's a WG on the floor in front of the bass cabinet, and it looks like this: http://www.partsexpress.com/pe/showd...number=270-310 (Dayton has several sizes in this series, 6~12in mouths. ) Is it any good? (or bad, since it's abandoned and put aside)

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