[Pinco Pallino]

Hello,

I am new to your forum. My interest is in inexpensive digital systems feeding custom speakers built by me.

Someone was looking for an inexpensive EQ/XO with digital ins and outs.
There is no such thing to my knowledge. However, it occurred to me that you could "build" such a beast by combining two or three Behringer DEQ2496.

Take two DEQs. Splice the coax out of your DVD or CD player and run it to the DEQs XLR inputs (by way of a Neutrik type shunt adapter). (If your DVD has two digital outs -- coax and toslink-- you can use the coax/XLR to feed DEQ #1 and the toslink to feed DEQ#2)

Use a combination of the graphic and parametric EQ's to create a two way XO: e.g. one for mid-treble (DEQ #1), one for bass (Deq #2).
Combining the EQs gives you sufficiently steep cutoffs to mimic a digital XO. Connect the DEQ's digital outs (XCRor toslink) with the digital ins of your amps.

A three-way XO can be similarly created by combining 3 DEQs, at still well under $1k.

As a bonus you still have the EQs to equalize your system/room.

Any comments?

Pinco

PS: it is IMHO always advisable to precede the DEQ's with Behringer SRC2496 upsamplers (promised to again be available by January) @ $125.

[J North]

My only question is how to attenuate volume?

[Pinco Pallino]

There are two ways of doing it: firstly, I discovered a DVD player with a digital volume control. for $49,99...

However, I think this is a pretty useless gadget because you want to enter the DEQs with all 16-24 bits available.

What you therefore need is  amps (or receivers) with a digital input per channel.

If you take, for instance, two Panasonic XR55s (or 70s) you will be able to activate both volume controls pari passu with only one remote. The 55 permits to combine the power of the front and rear channels which would give you a total of about 320 watts (160-200 w/receiver). Only problem: the Pannies have no fan; you cannot stack them without spacers in between.

[timbley]

Hello,



Someone was looking for an inexpensive EQ/XO with digital ins and outs.
There is no such thing to my knowledge. However, it occurred to me that you could "build" such a beast by combining two or three Behringer DEQ2496.

This is something you could do, but I wouldn't recommend it. The DEQ isn't intended as a crossover and lacks protective features. One accidental hit of a bypass button or accidental mode switch and your tweeters will be loaded with a full range signal before you know what happened. I speak from direct experience. Fortunately it was a cheap tweeter.

[kfr01]

This is something you could do, but I wouldn't recommend it. The DEQ isn't intended as a crossover and lacks protective features. One accidental hit of a bypass button or accidental mode switch and your tweeters will be loaded with a full r ...

Wouldn't a protective high pass filter (a cap) on the tweeter protect it..?

[kfr01]

Hello,

I am new to your forum. My interest is in inexpensive digital systems feeding custom speakers built by me.

Someone was looking for an inexpensive EQ/XO with digital ins and outs.
There is no such thing to my knowledge. However, it occurred to me that you could "build" such a beast by combining two or three Behringer DEQ2496.

Take two DEQs. Splice the coax out of your DVD or CD player and run it to the DEQs XLR inputs (by way of a Neutrik type shunt adapter). (If your DVD has two digital ou ...

The cheapest way I know of (if you already have a powerful PC) is to buy an RME rig with 6 pairs of analog outputs and find some pro audio software with good routing features...

There's a good thread on diyaudio.com-->loudspeakers about it.

I was once very interested in this.

My reading yielded the following conclusion:

Cheap and active speakers with digital processing don't mix yet.

I'll reevaluate in another few years, but neither the software nor the hardware seems to be there at a low pricepoint.

Your money, imo, would be better spent at this point in time in:

a) in savings until you can afford a one-box solution like the deqx

or
 
b) in voicing a passive xo (or going with a quality kit) and treating your room; perhaps supplementing with a couple bands of EQ on the bass.

[timbley]

Wouldn't a protective high pass filter (a cap) on the tweeter protect it..?

Yes, that would work. But I still don't think you'll be happy with this solution. I agree with suggestion a. in the last post: Wait for a one box solution like the deqx.  Better stuff will be coming along I'm sure. I've got a hack job system kind of like you are talking about with a bunch of Behringer gear and it's really a headache. Wires everywhere, and it gets out of whack frequently and makes funny noises and bad sounding music. I'm tired of it.

[Builder Brad]

The DEQ2496 seems to be well suited for develoment work with speaker design and should be used with other equipment to assist you in makning a hard wired active x-over for your speakers.

[Builder Brad]

Hi pinco,

just re read your post!

if you are looking at developing your own active x-over, and consider that <1k would be reasonable for an active x-over soulution I think that you would find the ASP kits on offer on the Linkwitz site interesting:

http://www.linkwitzlab.com/

The Linkwitz Orion is an active 3 way design which can be purchased in various kit and build stages. This could be a good place for you to start on your quest! The basic active x-over board (ASP )can be purchased on the site  and you could build the complete x-over and equalisation parts for less than half you figure.

The site is a work in progress and provides all the information regarding the develoment of a world class speaker.

[timbley]

I've got a hack job system kind of like you are talking about with a bunch of Behringer gear and it's really a headache. Wires everywhere, and it gets out of whack frequently and makes funny noises and bad sounding music. I'm tired of it.

Hello again Pinco,

I shouldn't have spoken so harshly of the Behringer equipment. I was in a bad mood the other night, and my system's acting up made things worse. I regret making that post. I know it's just one bad DXC unit that's causing all my problems, and most likely I damaged it while trying to tinker inside, which I should have known is beyond my skill level.

On further thought, I think your idea of using multiple DEQs as crossovers could produce excellent results and be easy enough to set up and use for a two way speaker design, maybe a 3 way, although I find keeping two receivers synched to be a mild nuisance at times. 3 would be more trouble still.

PS: it is IMHO always advisable to precede the DEQ's with Behringer SRC2496 upsamplers (promised to again be available by January) @ $125.

I agree. I'm really happy with the SRC. It's cleaned up some problems I was getting with the digital signal coming from my computer. The indicator lights make it easy to keep track of what kind of signal you are receiving and sending. It could also be used to split the digital signal between two DEQs.

btw, tonight a co-worker of mine came over and had a first time listen to my system, which is a 5 way active with concrete bass enclosures using two DCX crossovers. I was worried there would be problems, but everything seemed to be working correctly and he was astounded. He described it as  sounding "very present." He kept saying "It sounds real." I could see his amazement as his eyes darted from instrument to instrument in the virtual sound field.
When I first set up this system and listened to it, I was similarly amazed. Now I just expect that level of sound as a given and get upset if it isn't happening.

[Morbius]

Wouldn't a protective high pass filter (a cap) on the tweeter protect it..?

NO.

The tweeter ALREADY has a high pass filter in front of it - the crossover.

Accidentally hitting a bypass switch is essentially equivalent to turning up the volume
control excessively.  There's not much one can do to protect a tweeter from that -
not without filtering out the signal one wants the tweeter to see.

[kfr01]

Wouldn't a protective high pass filter (a cap) on the tweeter protect it..?

NO.

The tweeter ALREADY has a high pass filter in front of it - the crossover.

No kidding.

Accidentally hitting a bypass switch is essentially equivalent to turning up the volume control excessively.  There's not much one can do to protect a tweeter from that - not without filtering out the signal one wants the tweeter to see.

If a person were to hit the bypass switch, the tweeter would presumably be sent the incorrect signal for only a few seconds before the user could correct the problem.  A high value cap would create a first order filter.  Select a high enough value and excursion numbers that would harm the tweeter will be filtered out.

I'm not saying this is a perfect solution.  By adding the filter you're adding more phase complexity.  The value will have to be selected to be sufficiently below that of the electronic filter but high enough to filter harmful frequencies for a few seconds.

But, with some thought, it -would- be possible to both protect the tweeter and not affect the electronic crossover too much.

What's the problem?

[Morbius]

I'm not saying this is a perfect solution.  By adding the filter you're adding more phase complexity.  The value will have to be selected to be sufficiently below that of the electronic fi ...

I think that any filter that's impervious to the transient created by an accidental
switching of the bypass - will have a deleterious effect on the sound.  Any filter that
won't have a deleterious effect on the sound - won't protect.

Tweeters are pretty fragile - they don't stand up long to abuse.  I wouldn't count on
anything staving off a damaging transient for a time on the order of a human reaction
time.

If anything - you need something that will work like a fuse - if the tweeter is overloaded -
it blows instead of the tweeter.

[kfr01]

I think that any filter that's impervious to the transient created by an accidental
switching of the bypass - will have a deleterious effect on the sound.

I think we agree on this point.

This Behringer DEQ solution is already less than optimal.

If the original poster doesn't want to blow his tweeters in the event of a bypass switch, then he can protect them in any number of sub-optimal ways.

I quickly suggested a cap.  A large enough value, as sub-optimal as it may be, will protect the tweeter.  Sub-optimal?  You bet.  However, since he has upteen PEQ bands to fix any frequency response problems the phase distortion introduces, what will the final effect on the sound be?  Audible?  I wouldn't put money on it.  His end product will still only have 1 passive component and the benefits of digital crossovers will still be had.

You suggested a fuse solution.  Fast-blow would be a must.  Selecting a value high enough to prevent nuisance blowing and low enough to serve the purpose of protection might be more of a challenge than one would think.  Sub-optimal too?  Sure.