BMS Drivers

[dc270]

Boy, that sure looks nice active. My crossover is a TDM 24CX2. I'll be running my 811b/4552 from 6500Hz to 20kHz. The smallest amp I have is a Carver PM300, it's 100 wpc. Total overkill, all I really need is probably a 1 wpc tube amp for my HF component.

FWIW- I am using a MOSFET Hafler P1000 Transnove for the 3khz on my Rane 223 xover, sounds very good! Fact is I am also using a Hafler P3000 for the mids and a Soundcraftsmen 5002 on the low end. This active 3 way set up is the best sound I have had, especially with the a Crown premap
DC

 

[Coolhandjjl]

Here's the meat of my setup so far:
LF: SAE 2401- 250wpc
Mid: SAE A201- 100wpc
HF: Carver PM300- 100wpc
Preamp: Marantz 3800
X-Over: TDM 24CX-4

More watts then I know what to do with, preamp volume knob will probably never make it past the 9:00 position. (7:00 is off)

 

[skywave-rider]

John,
What are the MF/LF drivers? And does the mid use a horn?

 

[Coolhandjjl]

LF is a pair of horn loaded Eminence 3012LF drivers.

Mid is the Eliptrac 400 Tractric horn, good down to 400Hz. I haven't picked out the 2" drivers yet. The horn designer has gotten good results with the Faital Pro HF200 and the B&D DE85TN. However, both are titanium diaphragm divers, and I was hoping to use one with a non-metallic diaphragm. So far, there is the Faital Pro HF204, an 18Sound driver (forgot the model number, it is noted elsewhere) and also the Selenium D405 on my list.

 

[skywave-rider]

what's the mid?
It's a three way, right?

 

[Coolhandjjl]

It's a three way, mid uses the Eliptrac 400 Tractrix horn, I haven't picked out the driver yet, it's a 2" horn.

 

[skywave-rider]

OK John, here's the graph I promised. This is the same readout I linked to earlier, but smoothing removed and zoomed in vertically and horizontally quite a bit. I concentrated on the HF since that's what you will be using from the 811.

Altec 811B/BMS 4552ND/Active crossover and compensation/on axis/44". Please note that due to the central vane in the 811B, I skew the mic a bit to one side in the horizontal.

I think the 6.5 kHz crossover point you propose is too high bearing in mind the spacing between the MF and HF horns. Although I don't know the dimensions of your mid horn or the spacing between the center to center on your baffle, I think it will be too far apart. But you may find more info at this link if you have not seen it:
http://audioroundtable.com/forum/index.php?t=msg&th=8265

Additionally, the 811 beams at HF.

Have you looked at a small horn you could get closer to the mid? Maybe like the Crites tweeter? I am assuming you are set on not going 2-way.

I did a set of measurements on those here:
http://www.audiokarma.org/forums/showpost.php?p=4204591&postcount=2

 

[Coolhandjjl]

Wow, a lot to consider. One reason I went with the 811 as a HF was to time align all my drivers. It's one deep horn. The Crites tweeter gets rave reviews, but no way to physically align it. My crossover does not have controls for delays either.

The Eliptrac 400 horn I am using for my mid is designed for 400~20,000, so technically, I could run my system as a two-way. But the 811's I have in green have such a retro cool factor, it's worth a shot seeing if I can make it work. If not, I can certainly sell them off. Seems lile people are always looking for them.

Here's some info on the horn: