digital x-over for Alphas?

azryan · « **on:** 4 Oct 2003, 12:33 am »

Danny,

I know you use top quality x-over parts, but have you ever tried digital x-overs?

This Behringer "Ultradrive Pro DCX-2496 Digital 24-Bit/96 kHz Loudspeaker Management System" seems to be very cheap and very high quality and can do a tremendously impressive amount of things to speaker drivers.

I was thinking say... the Alphas...

You said you could cross the Neo's ~800Hz but it degraded the signal with what you had to do to hit that, but what if you could cross them over that low or lower with this digital x-over?

Looks like you can use the parametric e.q. in it too to maybe bump up the low end of the Neo's and cross them even over lower at the same time?
Also bump up that top 1/2 octave roll off too?

It'll adjust phase too. It does all sorts of things. hehe

Recently you mentioned a hair lower Alpha x-over design and also diff. inductors in the Alphas for diff. room sizes to balance the bottom end of the bass... these could be simple adjustments on this thing.

Seems like the only problem would be if it degraded the signal in it's A/D and D/A conversions, but seems like really good chips doing these steps, and the potential benefit could be great esp. on a speaker like the Alphas.

The hard part for me is that I can't actually 'test' what the best setting are, but you could and tell people where to cross the speakers over at and what slopes, how much e.q. and where, etc..

Any thoughts on this subject?

Danny Richie · « **Reply #1 on:** 7 Oct 2003, 11:03 pm »

Quote

I know you use top quality x-over parts, but have you ever tried digital x-overs?

Yep, I sure did.

I guy from Springfield, MO came down several times for me to measure and evaluate his digital pre-amp and crossovers.

It was excellent, and after making adjustments within the woofers pass band it sounded better than it ever did.

I think he is interested in selling his complete systems.

The crossover point is as low now as it needs to be.

I think forcing the Neo's lower would be a mistake, or the cons would out weigh the pros.

Oh yea, it had no A/D conversion. It took digital from the source all the way to the D/A converters which were located in each amp.

All it takes is money and time. The technology is here now. I tested this guys system about 4 years ago.

ekovalsky · « **Reply #2 on:** 13 Nov 2003, 09:17 pm »

Danny, was that a TacT or Accuphase system?

I've been considering a similar arrangement for the VMPS speakers (RM/x) have on order.

Danny Richie · « **Reply #3 on:** 13 Nov 2003, 09:35 pm »

No, this guy completely designed his own system from start to finish.

azryan · « **Reply #4 on:** 14 Nov 2003, 12:40 am »

Yeah...

I was gonna get a pair of the RM/X's myself, but then I thought instead I could get a pair of Alphas -for 5 differnet rooms! heheh

Just kiddin' with ya Eric. heh

Hey, did you ever do any of those room treatments??

ekovalsky · « **Reply #5 on:** 14 Nov 2003, 01:08 am »

Got a great price on them, you may only have been able to do 2 rooms.

Have eight 2' x 6' Respond Panels and four 6' quarter round bass traps on the way from Acoustics First. Foam and DIY fiberglass wasn't an option because of WAF.

Also rearranged the room so listening position is right in front of the wood and glass doors (makes a decent diffusor), that way walls are symmetric.

azryan · « **Reply #6 on:** 14 Nov 2003, 05:00 pm »

Hey, good stuff! I think you'd hear a BIG diff.!

"-Foam and DIY fiberglass wasn't an option because of WAF."

What's inside those Respond Panels? My guess would be foam or fiberglass? Or it's a diffusor type panel? I'll have to go look at 'em.

Make a nice frame and nice acousticly trasperent-ish cloth and DIY can look/act the same as a brand name though IMO.

"-Also rearranged the room so listening position is right in front of the wood and glass doors (makes a decent diffusor), that way walls are symmetric."

Glad you decided to go symetric. IMO that's a big part of adressing a room.

I'd think that'd be great when the doors are open. I'm not convinced that those doors act as a diffusor though? Yeah, the glass is beveled and the wood frame around each pane, but that's a lot of flat glass?

Did an acoustic treatment expert (I'm sure not one) look at a pic of the doors and say it acts like a diffusor?

You flyin' in the designer to set 'em up?

Good luck w/ that set-up!

Sorry O.T. but it's my own thread I'm messing up so I can do that right? hehe

ekovalsky · « **Reply #7 on:** 14 Nov 2003, 08:08 pm »

The Responds are compressed fiberglass. They come in 1" and 2" thickness (got the 2"). They are absorbers. Didn't buy any diffusors, I'll use furniture and accessories for that. The bass traps are the Geometrix quarter rounds. Prices aren't too bad, for about half of what Echobusters cost I'm getting double the treated area. http://www.acousticsfirst.com

The doors will diffuse some but obviously are reflective. I'll have the option of listening with the doors open (during the day) or closed. There shouldn't be much problem when closed since the listening position is so close to the door, there will be no significant time delay in the reflected sound. Got that from someone knowledgeable about sound physics and room acoustics, but I didn't pay big bucks for a thorough room analysis by a Ph.D type.

I'm going to try to set the RM/X up myself although may need some help (muscle) since they are 375 lbs each. I'm may help Big B set up his room at CES 2004 which I'm sure will be a helpful experience. If necessary I'll fly him in once the room is otherwise complete.

Sorry for being way OT