Well, guys, I have done a few more listening tests of my dipoles.
And I must report that subjectively they do sound great, certainly a lot better then my older Carvers Platinum Mark IV. I have been using the DEQ2496 and DCX2496 new Behringer units to arrive at the best crossover and filter slope points.
At this time I think that Jon’s revelation that RD-75 sounds better when crossed higher is definitely justified. I tried a range of values from about 250 Hz and up to 500 Hz and, well, 500 Hz is what I ended up sticking with. Also it would appear that 4th order slopes with L-R alignment is somewhat preferable to anything else, well, not much surprise there.
Overall, RD-75 driver is an amazing piece of engineering. It sounds so much better then any point source radiator I have ever heard. In fact it also sounds better then the original Carver planer-magnetic driver, which is very similar to RD-75 in construction. Now, who knows, may be my asymmetric and curved baffle is responsible for such a good sound, I do not know, and there is no way to find out, but I’d like to think so. The aggressive high frequency EQ, as it turns out, that I originally programmed into the DCX is not strictly speaking needed, the RD-75 is pretty flat up to 15 kHz, so a gradual boost from about 9 kHz up to 20 kHz with maximum amplitude of 5 dB is about right for my room.
My midrange array is 4 drivers, - they are the 10-inch SS 25W8565. I must say what a smooth driver this 25W is. I know that there are other choices out there and this one is far from being the most economical, but it is effortless and extremely smooth. Using 4 of them was a correct way to go, as I was not sure at the time of my design throws if I should go with 2 or 4 drivers. If you ask me now I would say that 6 would have been better in a separate baffle. But it would have been a very different speaker from the footprint point of view.
I wish I could post some frequency response curves, but to my shame I do not as yet own any measurement software. So I used the DEQ2496 with Behringer 8000 microphone and the signal generator, as an input source, to measure the SPL at discrete frequencies. The numbers looks pretty uniform, but it is not the way to do it. That brings me to a request.
I need suggestions for reasonably inexpensive audio measurement software. I already have a sound card that I think might be used for this purpose, - it is Delta 410 from M-Audio and a microphone, - Behringer 8000. The question is can I use DEQ2496 as a kind of microphone pre-amp? It would seem to me that the pre-amp is necessary, well; I guess I need suggestions for a complete measurement setup. Natural it would also be nice to be able to model the crossover in software and drive the speakers from a computer.
As for the woofers, I use standard Phoenix dipole woofers with Peerless 12-inch drivers as posted on Linkwitz’s site, well, - they are very authoritative. It would suffice to say that I am not going to need any more bass, - at least for a while. The bass is effortless and it sounds much better then Carver’s dipole bass. I used standard EQ as suggested by Linkwitz.
So in the end the ‘Chinese menu’ of components, as Jon once kindly characterized my set-up, actually worked rather well and I am very pleased with the results, as the sound coming out from the monster is simply massive. I still have to do a proper frequency response measurements and I am yet to use the RTA option as built into the DEQ2496, got to get a proper mike cable for that.
By the way, has anyone noticed that the display on the DCX2496 goes haywire during the music playback? The unit still works but you can’t adjust anything real-time. I should say that everything works for about 5-10 minutes of the adjustment process in the beginning, but then the problem starts. The display flickers and it takes a few minutes for the parameter you are playing with to get highlighted. Adjustment is not impossible, just incredibly frustrating. Has anyone observed this rather strange behavior? It looks like a display driver is in conflict with the internal number crunching. I guess I will have to talk to Behringer people to get this thing fixed.
Victor
And I must report that subjectively they do sound great, certainly a lot better then my older Carvers Platinum Mark IV. I have been using the DEQ2496 and DCX2496 new Behringer units to arrive at the best crossover and filter slope points.
At this time I think that Jon’s revelation that RD-75 sounds better when crossed higher is definitely justified. I tried a range of values from about 250 Hz and up to 500 Hz and, well, 500 Hz is what I ended up sticking with. Also it would appear that 4th order slopes with L-R alignment is somewhat preferable to anything else, well, not much surprise there.
Overall, RD-75 driver is an amazing piece of engineering. It sounds so much better then any point source radiator I have ever heard. In fact it also sounds better then the original Carver planer-magnetic driver, which is very similar to RD-75 in construction. Now, who knows, may be my asymmetric and curved baffle is responsible for such a good sound, I do not know, and there is no way to find out, but I’d like to think so. The aggressive high frequency EQ, as it turns out, that I originally programmed into the DCX is not strictly speaking needed, the RD-75 is pretty flat up to 15 kHz, so a gradual boost from about 9 kHz up to 20 kHz with maximum amplitude of 5 dB is about right for my room.
My midrange array is 4 drivers, - they are the 10-inch SS 25W8565. I must say what a smooth driver this 25W is. I know that there are other choices out there and this one is far from being the most economical, but it is effortless and extremely smooth. Using 4 of them was a correct way to go, as I was not sure at the time of my design throws if I should go with 2 or 4 drivers. If you ask me now I would say that 6 would have been better in a separate baffle. But it would have been a very different speaker from the footprint point of view.
I wish I could post some frequency response curves, but to my shame I do not as yet own any measurement software. So I used the DEQ2496 with Behringer 8000 microphone and the signal generator, as an input source, to measure the SPL at discrete frequencies. The numbers looks pretty uniform, but it is not the way to do it. That brings me to a request.
I need suggestions for reasonably inexpensive audio measurement software. I already have a sound card that I think might be used for this purpose, - it is Delta 410 from M-Audio and a microphone, - Behringer 8000. The question is can I use DEQ2496 as a kind of microphone pre-amp? It would seem to me that the pre-amp is necessary, well; I guess I need suggestions for a complete measurement setup. Natural it would also be nice to be able to model the crossover in software and drive the speakers from a computer.
As for the woofers, I use standard Phoenix dipole woofers with Peerless 12-inch drivers as posted on Linkwitz’s site, well, - they are very authoritative. It would suffice to say that I am not going to need any more bass, - at least for a while. The bass is effortless and it sounds much better then Carver’s dipole bass. I used standard EQ as suggested by Linkwitz.
So in the end the ‘Chinese menu’ of components, as Jon once kindly characterized my set-up, actually worked rather well and I am very pleased with the results, as the sound coming out from the monster is simply massive. I still have to do a proper frequency response measurements and I am yet to use the RTA option as built into the DEQ2496, got to get a proper mike cable for that.
By the way, has anyone noticed that the display on the DCX2496 goes haywire during the music playback? The unit still works but you can’t adjust anything real-time. I should say that everything works for about 5-10 minutes of the adjustment process in the beginning, but then the problem starts. The display flickers and it takes a few minutes for the parameter you are playing with to get highlighted. Adjustment is not impossible, just incredibly frustrating. Has anyone observed this rather strange behavior? It looks like a display driver is in conflict with the internal number crunching. I guess I will have to talk to Behringer people to get this thing fixed.
Victor
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