Subwoofer crossovers

I'll take the other side of Brad's argument.

Unless you're using full-range room EQ (ala Audyssey), the most audible of the passive-treatment resistive, room induced, problems occur between +/- 60hz and +/- 110hz in most rooms (IME, anyway). Bassbusters are great, but their effectiveness starts to diminish below 100hz, and is generally, entirely gone by +/- 70hz, IME.

If you're using subs, you can address these thorny problems with careful placement of the subs and/or deciated subwoofer EQ (SVS or Velodyne). Either way, the subs need to be the source of the output in this mid/upper bass range if they're going to the tool used to fix the problem. This means the subs need to roll off fairly high: somewhere north of 75hz in every room I've set up.

This usually makes a good "hand-off" to unfiltered mains impossible, unless the mains have no bass at all. Something like the Sunfire Ribbon Monitor might work, but most high-end mains have sufficient bass to relegate the sub-woofer to deepest bass only. You can't run the subs high enough to fix the nasty problem that subs are best suited to fix - unless you low cut the main speakers.

That's a mistake IMO. I know many, many folks prefer to eliminate an active x-over, but at 80hz, I find that even a modest cost unit like the NHT x-2 is very, very hard to detect. Of course, this "undetectability" depends both on the system in question and the listener in question, but I've A/B'd the X-2 in some very high end chains and, with suitable program material (i.e. no bass at all), I can't hear the difference. Also, of course, YMMV, on that one.

It's entirely possible that a truly crappy low cut for the mains like that in the Velodyne SMS-1 may be a different story. I'd agree that decent active x-over is important. But, shy of that, I believe that any deterioration introduced by a decent active x-over is (IMHO) likely to be swamped by the benefits of crossing the subs out higher in frequency than is usually possible when the mains are run full-range.

A lot of people note that there are also benefits to relieving certain mains of the heavy lifting in the mid/upper bass, as well, but - IMO- that's just a little icing on the cake.

Just the other side of the coin.

Marty

I cross at 75 hz in my current room, because that's as low as I can go and make it work. I have gotten below 70hz in a previous room, but never down to 60hz.

My point is that full range speakers in free space start to exhibit really difficult behavior somewhere not too, too far below 100hz in most rooms. Wherever that point is, that's where I feel that you're best off crossing to subs (if you're using subs), because the subs will almost certainly allow better behavior.

Whether that makes your system a sat/sub or not isn't really that important to me. Not to me, anyway, tho others might be more concerned.

Marty

BTW, Have you ever crossed your Verity Parsifal mains straight to the JL subs without the Verity bass cabs? I also have P/Es and tried it once with my Rythmik subs. I know that it's odd (and might not be appropriate for a long term configuration), but it was both interesting and educational, (and reasonably easy with the SMS), if nothing else. I'd be curious to see how it flew with your JLs.

Hevac,

I've never used the LFE in, so I don't know the answer.

Marty

Re:

Marchand x-over. I just want to clarify my experience. I bought a used Marchand that had been re-tubed by the dealer, but it was still noisy. I returned it and bought an X2 for interim use while I decided how to proceed with a permanent x-over solution. The X2 turned out to be good enough to keep - so I did.

However, this shouldn't be taken as a thumbs down on the Marchand. It's entirely posible (maybe even likely) that the issues I had were with that particular unit, especially given that it was used.

I don't think anyone should extend my experience with that unit to an evaluation of that model. I certainly don't.

Marty