Has anybody tried using the supposedly very good BMS 4590 2" compression driver in a PI system ? it's a dual concentric design so the crossover needs an additional crossover frequency ?.
An audiophile Pi seven would then end up as a 4 way system.

Cheers
Andreas

That is a pretty cool compression driver ey! I havn't seen a comp driver with seperate diaphragms to cover different frequency ranges before. It's got two voice coils and each needs a crossover network. Apparantly they act as a point source togethor, so I guess the audiophile series could be termed 3 way system still.

Doesn't the audiophile series have a midrange as well? The BMS 4590 can be used 400Hz to 21KHz, just seems a little bit of a waste to use this expensive compression driver when the HF horn in the audiophile series does not need to cover this much bandwidth. This comp driver looks like it doens't need a compensation circuit, so you would have to attenuate it anyway to match midrange sensitivity in the audiophile 7 Pi. I think its a bit of a waste to use the BMS 4590 IMO, but would be great for 2 way system with xover at 400Hz. For Audiophile 7 Pi, I would guess that a 1" exit driver would be best suited practically. It would need compensation, although that should not be a problem as Wayne's got the crossover schematics and it also matches the sensitivity too.

Adrian

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Good stuff!

I have heard that the 4590 and the 4592 neodymium should be really awesome. However I haven't personally heard any of them.

What i have on shelf is a couple of jbl 2245 and a 8" focal axiom midrange driver which i suspect could be used instead of the jbl 2123 in an audiophile system.

cheers
andreas

What's the sensitivity of that focal driver? If I recall, they're L.E stuff. Maybe I'm wrong though, I havn't checked out focal's stuff in years actually.

I would love to get my hands on a 4590 or 4592 as well!

Adrian

In general the focal stuff is more sensitive than scan-speak og vifa type of drivers.

cheers
andreas

If you wanted to use a driver like a 4590 or 4592 in a pi system it would then become a three way system. This would be a variation of Wayne's Audiophile design that is a 3 way system using a 10" for the midrange.

You wouldn't necessarily be wasting the bandwidth of the 4590 or 4592, because this driver is capable of taking the place of the 10" cone driver.

BMS recommends a lowest crossover point for these drivers to be 400hz. I have made test and measurements with FFT Spectrum Analyzer and The driver does have very good response to 400 rolling out down to 300. If horn you use will load down to 250 or 300 I would say crossing these drivers at 400 is no problem at all. The BMS recommended crossing point for the mid to hi is 6300hz and there should be no deviation from this. 6.3-6.5khz is the best spot.

Aside from all this I have some personal opinions that are purely subjective and just what I like. Generally speaking I like crossing into a 2" format driver around 750hz and a 1" driver at 1600hz. This is largely depending on the woofer. If you look at woofers like a JBL 2226 or kilomax they run up to 1600 with out problems. crossing them over at 600-800 is a great spot. For me this puts less strain on the compression driver where it's working the hardest. Pushing the compression drivers down to the cut off point is is fine and they are design to do so with steep enough crossover slopes. I find they sound nicer when not pushed quite so low.

The 4592 IS by far more sonically superior to the 4590. The 4590 sounds fine but 4592 is very very sweet sounding. For that matter I also find that all 3 neodymium models outperform the ceramic magnet counterparts.

My favorite driver is the little 4540. This has to be crossed at 1600hz or higher. The recommendation is a little higher but there has been no problem with home stereo use. the 4552 will cross lower is you need but I feel the the small one sounds better.

That's all the info and opinions I can offer about the BMS parts. Take it for what it's worth. Free information and I sell them.

Bill

I had some questions regarding the 4590. If one were to use the Eminence crossover (3rd order high-pass, 2nd order low pass @ 1600hz) in a JBL 2370, how much power could it take and how would you equalize it? It seems to have a rising high end above 15KHz. Do you need to compensate for this?

Dave