Bohlender Graebener RD50, Multiway Crossover Plans....

[GMark]

Does anybody have any diy plans for the BG RD50. I happened to have bought a pair at a very good price. I love the midrange and I do not have test equipment but it seems it needs a midbass covering below 200/300Hz and supertweeter covering above 10KHz. I do not want to use an electronic xover.
Currently I also have a pair of Hiquphon OWIII maybe I think I can use as supertweeter? Advice also for midbass? To keep a slim profile I want to put the midbass below the RD50. I will use my NHT 12 inch sub below 100Hz.

[geraldfryjr]

Have you looked at dayton RS series? jer

[GMark]

geraldfryjr Thanks for the reply but I am looking for plans already made up with crossovers and speakers. I have seen the Colossi design but is too big for my living room.

[craigj]

GMark,

You might want to look over here: HTGuide Forum - New Home for the BG Ribbons - Part 27 Very valuable info from people who have BG products.

Cj

[GMark]

Thanks CJ. But as I skim through the thread the arrangement is for a midbass array beside the planar panel and not like BG's Radia 520 which I am trying to duplicate with higher quality midbass speakers.

[ptwining]

I use the B&G RD40's a lot. I have found that (with a properly designed cabinet) that a pair of the CSS SDX-7 is a fabulous match for the B&Gs.

I have always implemented the B&G/CSS combo as a hybrid-dipole with a scanspeak tweeter to crisp up the slightly weak top end of the B&Gs. Do not ignore the B&G instructions about their recommended notch-filter. The necessity is due to a cavity resonance that is inherent to the physical design of the driver itself. Believe me, it makes a significant difference.

I have found that something (at minimum) of 1.3/1.5cu reflex will support authoritative low end that is a match for the "hot" b&G's.

The bad news is though, IMHO, forget it with a passive XO. The B&G's are fabulous drivers but rarely used because they need a lot of correction. I use the Digmoda B&O triamps with the onboard KSC DSP for digital 3-way XO and room correction.

Keep us posted!

[edit] You are right, you can push the low-end of the XO down to about 250 with a steep filter and the B&G performs pretty well. Personally, I'd let the big-guys run to 20KHz and then "top-up" the high-end. You don't even want to think about trying to time-align anything with the RD series without a real fast tweeter and digital control. That being said, the RD provides plenty of sizzle, so - counter-intuitively you want the tweeter to bring some "woodiness" or some "organicity" to the overall sound. The B&G is plenty fast and bright and unlike a traditional implementation you want the tweeter to "bring-down" the overall edge and rescale the music to the human ear.

The good news is, the result is absolutely surreal. The cost is *high* but you couldn't touch a competitive commercial product for more bucks than you'll have in the next five years...

Again, keep us in the loop!

[edit] silk dome tweeter.

Tom

[jgwinner]

Hi

I'm actually interested in the RD75's, but it seems like they would have similar crossover constraints.

I was thinking of the Beringher DCX2496, but would also like to do a passive crossover once I get everything dialed in. It sounds like this isn't really possible? I'm worried about delay and sync with the Video signal (home theater application).

I'm actually thinking of building these into an entertainment console, so I wouldn't be going dipole, it would be a built in, thin box with the subwoofers in a shelf (and mounted to the rear wall or floating on some spikes.)