P. Audio PH-4525 horn and BM-D750 (aka. K69)

[Rudy81]

I took some pics of my installation in the DBB and the center La Scala. Thought I would add them to the thread.

[Rudy81]

This is how the modified La Scala turned out. I hated taking a jigsaw to the cabinet, but I MUST have good timbre matching in my HT. All in all, it was well worth the skipping heart.

[Rudy81]

This is the front of the HT, now finished.....I think. [:|]

[DrWho]

Yikes, is the throat rectangular on the P.Audio horn? Do you get any frying bacon with high-hat and snare hits?

[Rudy81]

Dr. Who, the throat is a strange combination of a rectangular cutout with a circular cutout within the rectangle. It is hard to describe really. I have not noticed any odd sound colorations or distortions at any frequencies. Frankly, every time I sit to listen to music I am awed by the 'liveness' and accuracy of the reproduction.

I think someone had taken a close up shot of the throat a while back.

[Rudy81]

Dr. Who. This link contains the original discussion on these horns and there is a closeup of a similar, if not identical, Goldwood horn. http://forums.klipsch.com/forums/t/133893.aspx?PageIndex=5

My P. Audio horns have the center of the rectangular area rounded out IIRC.

[KdAgain]

Do you know of a cheaper version of the 2" driver that Rudy used, the P Audio BM-D750?

I'm
not SkyDover, but what's the application? There are plenty of other
cheaper drivers that should yield similar bandwidth at the expensive of a
little extra distortion.

Also, does it need to be a 2" driver?

The above was in Rudy81s thread on "JCC DBB Speakers". I thought it more appropriate to be in this thread so am responding to Dr. Who here.

The application is for my 1958 Khorns and a Center I hope to build later on. I have long planned to go Active and am in the process of acquiring equipment to do it. While Rudy had his Khorns he seemed very pleased with the PH-4525 & BM-D750 as replacements for his original mids and tweeters. If I can go 2 way, and at a reasonable cost as he did here I would like to.

I'm suprised that this combo is going high enough to eliminate the tweeter and I know it's pushing the bass bin to go high enough with these.

Thanks for suggesting cheaper drivers, but if there is much additional distortion I'm not sure I would want to do that. Re the 2" driver, it seems that most who have gone to the larger size are very pleased.

I sure appreciate your interest in this and value your expertise.

Rod

[Rudy81]

Rod, several comments here.

1) Yes, I did put the P. Audio combination in my Khorns at one point. One issue I ran into was that you are really pushing the BM-D750 to get down to 400Hz. That was one reason I kept searching for a bass bin that would better match the two way setup. I considered the Jubilee bass bin, the Jamboree, and the DBB. Since it would be my first build, and after many discussions with JWC and other owners of the DBB, I decided to go that route.

2) While I had my Khorns in 3 way, I ran some HF tests in my room to see how high I could hear. At about 17kHz, I could not hear much, if anything. So, I can't comment on the very high end of the 2" driver since I can't hear it anyway. But, what I can hear is more than adequate in the HF department. I do have a high shelf boost in my crossover to help out the driver keep a consistent level above 10kHz. Several of my posts have plots of the response in my room posted, so you can see the measurements I have taken.

3) I have researched drivers until I was going crazy. Very few reasonably priced drivers can do what the P. Audio driver can accomplish, that is why I ended up with it....at least from what I could research. I paid around $160 per driver, NIB for mine.

4) Purely by accident I found that the performance of this driver/horn combination is superb once you move the top hat away from the side and rear walls. That is an issue that is difficult to work around with a Khorn. I did get very good results when I first used them on a Khorn. However, when I finished the DBB build and properly placed the speakers in my space.....WOW, what a difference. The soundstage is simply amazing in my room. I never got that type of response with my Khorns, either stock, with JBL drivers on Trachorns, or with the P. Audio gear.

If you are ever in the Dallas, TX area, let me know and you are more than welcome to stop by and have a listen.

[Rudy81]

Yikes, is the throat rectangular on the P.Audio horn? Do you get any frying bacon with high-hat and snare hits?

Dr. Who, I managed to take a closeup picture of the throat using my iPhone for you.

[KdAgain]

Rod, several comments here.

1) Yes, I did put the P. Audio combination in my Khorns at one point. One issue I ran into was that you are really pushing the BM-D750 to get down to 400Hz. That was one reason I kept searching for a bass bin that would better match the two way setup. I considered the Jubilee bass bin, the Jamboree, and the DBB. Since it would be my first build, and after many discussions with JWC and other owners of the DBB, I decided to go that route.

2) While I had my Khorns in 3 way, I ran some HF tests in my room to see how high I could hear. At about 17kHz, I could not hear much, if anything. So, I can't comment on the very high end of the 2" driver since I can't hear it anyway. But, what I can hear is more than adequate in the HF department. I do have a high shelf boost in my crossover to help out the driver keep a consistent level above 10kHz. Several of my posts have plots of the response in my room posted, so you can see the measurements I have taken.

3) I have researched drivers until I was going crazy. Very few reasonably priced drivers can do what the P. Audio driver can accomplish, that is why I ended up with it....at least from what I could research. I paid around $160 per driver, NIB for mine.

4) Purely by accident I found that the performance of this driver/horn combination is superb once you move the top hat away from the side and rear walls. That is an issue that is difficult to work around with a Khorn. I did get very good results when I first used them on a Khorn. However, when I finished the DBB build and properly placed the speakers in my space.....WOW, what a difference. The soundstage is simply amazing in my room. I never got that type of response with my Khorns, either stock, with JBL drivers on Trachorns, or with the P. Audio gear.

If you are ever in the Dallas, TX area, let me know and you are more than welcome to stop by and have a listen.

Rudy,

Thank you very much for your well thought out and helpful reply.

I understand why you made the change to the new bass bins, but I'm not prepared to go that far yet. It's been awhile since I read your trials and tribulations with the
PAudio Horns and Khorns - I need to go back and reread it all. I guess you had a bit of a gap between the low end of the PAudio and the bass bin, but how noticable was it?

I don't mind spending the money on the BM-D750 drivers, but as I asked in another thread wondered if there might be a generic equivilant to this one such as Skydover found for the horn. Re the top end of the horn, did you run any sweeps to determine how high it will go? I think it's rated to 17k.

I recently heard a very high SQ system (not Klipsch) with the speaker location optimized for soundstage and it was stunning. And with your results and others from getting the speakers out of the corners I can certainly see the large benefit of it. You suggested in another thread that I put backs on my Khorns to allow non corner location. I need to look further into the amount of work required, but will probably lean in this direction.

Rudy it's very gracious of you to offer a listen to your system. Don't know if we can ever do it since we live way up in British Columbia, but I would sure love to.

Thanks again,

Rod

[djk]

"I don't mind spending the money on the BM-D750 drivers, but as I asked
in another thread wondered if there might be a generic equivilant to
this one such as Skydover found for the horn."

This is an OEM P-Audio BM750.

Here is another OEM of the P-Audio BM-D750.

http://www.paudiothailand.com/pdf/products/BM-D750.pdf

The first example in lots of five pair would be around $103.75 each (plus shipping), the second would be around $145 each (plus shipping). Single pair prices would be about 10% higher.

[KdAgain]

djk - I checked the link you gave for the pdf of the BM-D750. I believe that's the one Rudy bought. But I'm curious about the first one - don't see a link to any info or pricing on it. It looks different, but do you believe it to be electrically and acoustically the same as the PAudio BM-D750?

Thanks very much.

Rod

[Rudy81]

Neither of those pictured are the ones I have. Mine are physically identical to a K-69, just colored blue and no Klipsch logo. Mine is pictured here: http://forums.klipsch.com/forums/t/134856.aspx?PageIndex=1

[djk]

"djk - I checked the link you gave for the pdf of the BM-D750. I believe that's the one Rudy bought. But I'm curious about the first one - don't see a link to any info or pricing on it. It looks different, but do you believe it to be electrically and acoustically the same as the PAudio BM-D750?"

Other than the plastic cover, it's identical (to the BM-750). The BM-D750 is supposed to be improved, I haven't tried one to find out if this is true (or not).

It's a closeout item from a distributor that sells to dealers only, so I didn't provide contact info. In lots of five pair would be around $103.75 each (plus shipping), about 10% more for one pair. I will arrange a group buy if there is interest.

"Neither of those pictured are the ones I have. Mine are physically identical to a K-69, just colored blue and no Klipsch logo."

Yours is identical internally to the first example, the cosmetic back cover is the only difference.

[garyeanderson]

"djk - I checked the link you gave for the pdf of the BM-D750. I believe that's the one Rudy bought. But I'm curious about the first one - don't see a link to any info or pricing on it. It looks different, but do you believe it to be electrically and acoustically the same as the PAudio BM-D750?"

Other than the plastic cover, it's identical (to the BM-750). The BM-D750 is supposed to be improved, I haven't tried one to find out if this is true (or not).

It's a closeout item from a distributor that sells to dealers only, so I didn't provide contact info. In lots of five pair would be around $103.75 each (plus shipping), about 10% more for one pair. I will arrange a group buy if there is interest.

"Neither of those pictured are the ones I have. Mine are physically identical to a K-69, just colored blue and no Klipsch logo."

Yours is identical internally to the first example, the cosmetic back cover is the only difference.

I would be interested in a group buy if there was enough interest. It would get me a step closer to finishing the heavyweight La Scala Clones that I have started and alow me to run the Klipschorn tops with the bottom bass bins again.

[KdAgain]

djk,

Very kind of you to offer a group buy. I'll certainly be interested once I confirm that this is the best way for me to go, ie with the khorns. There is the issue of pushing these hard to get them to play down to 400, and I still don't know how much of a problem that may be.

Any way of finding out the differences between the BM-750 and the BM-D750?

When I proceed I'll need 3 drivers and 3 horns for the 2 Khorns and the new center I'll build later.

Thanks,

Rod

[Chris A]

There is the issue of pushing these hard to get them to play down to 400, and I still don't know how much of a problem that may be.

Speaking from experience, I don't believe that you've got any worries there: I've been using one of my "leftover K69s" with a PH-4525 horn as a center channel with a Heresy bass in between two Jubilees. It sounds pretty good to me--crossed below 450 Hz. I'm using an EV Dx38 crossover and a Crown D-75A to biamp the center.

Chris

[Guest " "]

I have both the k-69 and the d750's.

the d750s claim frequency response of 500 - 18khz with a recomended xover of 800hz

I think the MCM grand IV's uses this driver as a tweeter in a 4 way system.

If your going to use these other wise at a low volume, id cross them over using a steep crossover.

If you look at the plots for the driver, it look likes the impedance rises below 800hz quite a bit.

don't forget this is an 8 ohm driver, and not a direct replacement for the k-55.

Impedance

8 ohms

RMS Power Rating 100 Watts above 500Hz

Sensitivity (1W/1m) 108dB

Frequency Response

500Hz - 18kHz

Recommended Crossover 800Hz or higher

Voice Coil Diameter 2.84" / 72.1mm

Mount Type Bolt-on

[KdAgain]

There is the issue of pushing these hard to get them to play down to 400, and I still don't know how much of a problem that may be.

Speaking from experience, I don't believe that you've got any worries there: I've been using one of my "leftover K69s" with a PH-4525 horn as a center channel with a Heresy bass in between two Jubilees. It sounds pretty good to me--crossed below 450 Hz. I'm using an EV Dx38 crossover and a Crown D-75A to biamp the center.

Chris

Chris - Some encouraging words there. How does the center horn do with those big ones on the Jubes? And the 'little' Hersey bass too? Doesn't seem like great timber matching, but I'm very pleased that you are pleased! Are you also running a sub?

Anyway thanks very much - you are giving me much more hope.

Rod

[djk]

The impedance rise below 800hz, and low frequency response are strictly a function of the horn size.

6dB crossover is not recommended.