XLR/RCA dilemma

Bob, your point about connecting the RCA outputs from the preamp directly to the subs and using their crossovers is well taken.  They're Velodyne HGS-10s that I've had for years and always used with an SMS-1 that does room correction, so I hadn't thought about using the internal crossover.  OTOH, the unused SMS-1 is sitting in the cabinet and entirely adequate for providing below 100 Hz to the subs.  I'll see if I find a use for the 10B or I try to sell it.

db

"I've pretty much decided to follow Charles Hansen's recommendation to stay out of the Ayre balanced link.  I'll fully bung the LS50s, and use the Bryston 10B only to send 100 Hz and below to the subs."

Sorry if you didn't understand my post, but my comments went beyond balancing. I looked at my post again, and I definately wasn't clear. Balancing is only one problem. What I should have also included was that given what your current system is, and your current solution for a sub, won't work. You can get sound out of it, but it will never integrate properly. There's just too many things working against it. Your electronics are capable of a tremendous amount of deail and speed. I don't really care for the LS50 myself, but they are detailed and fast also. Unless you don't care about the quality of bass you're getting, there's just no way the sub is going to be able to keep up with the rest of the system. The Bass will almost certainly be detached, boomy and definately, very slow. There's just too big a gap.

The only people integrating a sub into a system like yours, are using a 2 of them, and are specificly made for stereo only, and have first order xovers. And you would wire them up using the speaker cable method I touched on in my last post. And even given all that, its not easy. You may think you have it, but it won't last. It will annoy the hell out of you, and you'll end up disconnecting it. 

This is Bobs statement from above.

"db, I assume your subs have low pass filters, so I don't see the point of using the 10B at all. Or I'm not understanding how you plan on connecting things."

On that, I have to agree. The sub should have whatever you need built into it. The Bryston xover is really meant for an all Bryston system, or matched with components that sound similar. Ayre and Bryston are completely different sounding.

"My understanding is that a ported cabinet has a 4th order roll off in the bass. That appears to be the case looking at Fig 3 of Stereophile's measurements. Sealed cabinets have a 2nd order roll off. So the roll off is slower, but will start sooner. Assuming that's true, then even though the woofer is distorting the level is being attenuated earlier. I think the net effect is that the distorted sound will be at a lower level. Since the LS50's woofer starts distorting so early, attenuating its output earlier seems like a good idea."

Normally I don't agree with Bob, but he's right on this too. If you read between the lines, you'll see were both saying that there will be some big compromises made here. We're taking a different path, but we end up in the same place.

"Will this yield as clean a system as high passing the LS50? I don't see how, but I can understand that signal purists would be happier."

On this, its not about making me, or anyone else happy, with the exception of the OP. I understand why you would use the term "signal purist". Its not the worst way to put it, but I would say its a general compatability issue, along the lines of what we've been talking about. The way I personally woud describe it, is that the sub, and its related products, are undoing some of what the Ayre has done.

Maybe you have a friend that can lend you some gear to try before you commit to an expensive purchase.  

sfall, you've given me a lot to think about, and I thank you for it.

Not sure I buy the speed issue with the sub.  My post doc work was in binaural processing.  Wavelengths at 100 Hz are long, and detection of phase is generally a complex issue and I haven't followed the psychoacoustic literature for decades.  But I think I understand your point about using speaker leads to subs, if you have to have subs.  I haven't addressed the issue of subs for a couple of decades.

I don't use subs for music in my other setup comprised of a Parasound JC 3 phono stage, JC 2 preamp, and JC 1 monoblocks that drive a pair of KEF Reference 107/2s, but the 107/2s extend to 20 Hz nicely.  I like the sound of the LS50s, but I don't love it like I do that of the 107/2s.

A friend who does setup for manufactures at shows tells me he uses a Beveridge RM-3, high-passing to ESL 57s, low-passing at 100 Hz to woofers.  If I choose to go that way, he can help.

db 

Sfall - is completely correct. I’m using Vandersteen 5A’s with Ayre, and the 5A’s have amplified subs built in. Ayre can install any needed circuitry in your Ayre if desired.