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Thanks!

Garland]]> GarlandB 2011-09-21T17:57:24-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69561&th=16656#msg_69561 Oh, yes, definitely. That box is perfect for a sub. You can use the Omega 15A or Omega 18A, or you can use the JBL 2235 or 2245. All are tuned pretty well in in that box. The Eminence woofers have an EBS alignment, the JBLs are pretty much max-flat.

If you are going to push it hard, you might go to a larger diameter port and cut the length to tune it to 30Hz. But the (Theater 4) port it has now will work just fine as it is, and will provide a lot of oomph without chuffing. Unless you're just trying to pull the drywall off the studs, it will sound great just plugging the tweeter hole and dropping the woofer in.

]]> Wayne Parham 2011-09-21T18:58:44-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69562&th=16656#msg_69562
Thanks!

Garland]]> GarlandB 2011-09-21T20:28:56-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69563&th=16656#msg_69563 Don't high-pass the mains, let them run wide open. Low-pass the subs depending on their distance from the mains. If you only have a couple subs, make them flanking subs and low-pass them around 90Hz. Put the mains on stands, and put the subs on the floor just beside and behind the mains. One sub beside each main, run in stereo as left main/flank and right main/flank. Each sub should be a couple feet away from the main it is flanking in each dimension, e.g. behind, below and to the side. Make them symmetrical with the mains, mirror images of each other, with the subs just inside or outside. I generally like them to the outside, but I've measured a few rooms that were better with them inside. Either way is better than none, waaaay better.

If you have another sub or two, put them further away, on the other side of the room, and low-pass them around 50Hz. These more distant subs can be put just about anywhere you have room and they'll help. If you have your druthers, put them at side wall midpoints. Another good configuration is four corners, so if your flanking subs are near the front two corners, put a pair of distant subs in the back corners. But like I said, pretty much any location will work. Once you get this many subwoofers in the room, it almost doesn't matter where you put them as long as they're not all grouped together. Spread them around.

You can't re-purpose components from the Theater four π crossovers for subs, although they are still pretty much the same crossover we use today in the mains. The tweeter circuit capacitor that used to be 8.2uF is now 6.8uF, but that's the only difference. Woofer circuits were always unique to the woofer you had, Zobel values changed and sometimes the core splitter components did too. I think the woofer values in your crossover are pretty much the same as what is used in the current model three π model with the Delta 12LFA woofer. So but the point is, your old Theater four π crossover is pretty much the same as the current crossover, but that's no help to you for a sub.

What I would suggest for a sub crossover is an active crossover and separate amp. This can also be implemented as a plate amp. I've used the Rekkhorn F1 sub crossover, and it worked pretty well. It allows variable adjustment of the (24dB/octave) low-pass frequency and amplitude. But honestly, I kind of like this modded Pyle crossover better. It has a gentle 12dB/octave slope, which works very nicely for multisubs which are supposed to be blended with the mains. It's definitely not as cool looking though.

]]> Wayne Parham 2011-09-21T20:49:06-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69564&th=16656#msg_69564
]]> gofar99 2011-09-21T22:59:08-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69565&th=16656#msg_69565 I thought about those Marchand crossovers, and may still give them a try. They certainly have a good reputation. The thing is, I prefer a gentle 12dB/octave slope for multisubs, especially the flanking subs. That's what attracted me to that Pyle crossover - I searched for 12dB/octave units and found very few. Most are 24dB/octave, a few are 18dB. For multisubs, we want blending, so a gradual slope is better.

]]> Wayne Parham 2011-09-22T01:01:18-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69566&th=16656#msg_69566 gofar99 2011-09-22T04:01:02-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69567&th=16656#msg_69567 That's definitely worth looking at, since that chip is about 75¢. I use a $25.00 Burr Brown part (OPA627) that requires two plus a daughterboard to complete the swap - and you need two of each to complete the upgrade, a total of four OPA627 chips. The Burr Brown parts are pricey, but they sure sound good.

]]> Wayne Parham 2011-09-22T13:00:35-00:00 http://audioroundtable.com/forum/index.php?t=rview&goto=69569&th=16656#msg_69569 ]]> Shane 2011-09-22T15:47:16-00:00