Building first speaker using DEQX

[Bill Hobba]

Hi All

I am about to embark on my first speaker building project. After looking into it I believe the hardest part is designing the crossover. Then I found out about the DEQX - http://www.deqx.com/index.html

It looks as though it makes crossovers a snap and you get room correction as well. I did a search for others building speakers using this device and did not find any. Is there a reason for that other than cost?

I am thinking my first speaker will use a 5 inch focal or seas magnesium driver and either the Hiquphon or Raven ribbon tweeter in a small sealed box. Any thoughts on what may be the best choice?

Do people think it is better to use a QTC of .5 (transient perfect) or .7 for maximal flatness? I am tending towards .5 because a frequency response flaws can be corrected by the DEQX but it can not correct flaws in the transient performance. I also have a rather good subwoofer (an old Richter Evocotor).

Also does anyone have any experience in buying speakers from Zalytron and having them delivered to Australia?

Any thoughts greatly appreciated.

Thanks
Bill

[audio-kraut]

Cost is most likely the main reason, as diy speaker builders are usually the ones where cash is not always at the ready.

I and quite a few others in this here forum use the behringer dcx 2496 sometimes in combination with the deq 2496 at a fraction of the price with probably not all that much a difference in sound - imho, not having been able to assess the deqx myself because of the reasons already mentioned.

[planet10]

DEQX is one of the early vendors of a product category that will explode in the next short while, and prices of devices with its capability will plummet (and features & capability will explode) -- it is a very expensive unit.

As the prices of computing platforms continues to go down, a dedicated XO PC becomes a serious option (the DEQX is after all justa a computer with dedicated software).

There is also the question of the impact the ADCs/DACs have on performance. If your system is limited to digital front-end and you are sending a digita signal to the XO then only the DACs play a role. For those with analog front-ends then the advantages of adigital EQ are often negated by the very digitization process.

If this is your 1st DIY, take a long lok for something that is already well sorted, build that and put the $$$ for the DEQX in the bank... because next year you'll be able to buy a new set of drivers & something better than the DEQX with what you stashed away and still have change...

dave

[Bill Hobba]

Hi Audio Kraut

Yes those products are much cheaper. And like you I am not sure if they are much of an audible downstep over the DESQ. My reservation is the phase response. I have been assured by people who have listened to it that the phase coherency of the DESQ is simply stunning. You can place subwoofers virtually anywhere - up against walls - whatever you like and the sound is perfectly time aligned. However at the price I may get a demo before purchasing. The only reason I may not is the designer Kim Ryrie is well known to me from my electronic hobbyist days. He really know his stuff to the point where I am willing to risk it.

Thanks
Bill

[Bill Hobba]

Hi Planet 10

Yes it is a very expensive unit and I agree the prices will plummet quickly. Indeed the DESQ has already announced a substantial price cut and they are looking to add extra features such as software upsampling. A really great enhancement would be to include the kind of algorithms found in the anagram upsampler - they are supposed to be stunning. I will need to think very carefully if I want to be on the bleeding edge. But the tinkerer in me would really like to give it a go - I have the itch. Food for thought.

Thanks
Bill

[audio-kraut]

It does not have the steep slopes the deqx boasts, but sofar my experience with the behringer have been overwhelmingly positive.
At the price one could persue the cheaper route first - it is after all a diy project, so upgrades are almost always no problem for the pesron undertaking the design and building - and once satisfied with the results of building - invest the money in a supposedly better - i.e. more expensive - product.

I agree wholeheartedly with aktive crossovers - a route I have taken since 1989 - but I think it is advisable to build the speakers using some decent amps and reasonable priced digital x overs first and once satisfied invest the money (when felt necessary) in some higher priced digital equipment - or go the computer based route (although the dcx allow remote control through - preferably - a laptop)

I have not seem any measurements regarding the phase shift in the crossover region of the dcx, but I doubt it will amount to much - and you can within degrees adjust the phase angle in the behringer.
Also the auto time alignment of the behringer works within millimeters, so I do not believe there is much of a difference in capabilities there.

The only advantage I can see in the deqx is the built in outo q function (which requires a deq if the dcx is used) and the up to 300dB/octave steep slope.

I had some minor problems with the less than optimal xlr connectors, but once identified the solution was easy.

[planet10]

Originally posted by audio-kraut and the up to 300dB/octave steep slope.

just reviews mind you (but more than 1)... didn't like using anything steeper than 4th order.

dave

[paulhfx]

What do you guys currently using digital crossovers do to deal with the noise from these units (ie higher-frequency hiss)? Or is it a problem?

Thanks,

Paul

[AndrewT]

Hi,
According to the dcx thread you must run the input right up at the limit of the analogue input (+22dbu).
Noise is not a problem then.
Overload of the power amp becomes the problem - add a resistive attenuator to the power amp input.
I tried asking what voltages were needed at the input to dcx but no one replied. I've since bought one.
A normal CD player puts out about 2Vac (rms) at digital maximum.
dcx needs 9.75Vac (=+22dbu) so a gain of times 5 is required before dcx. Other sources may require even more gain.
All your volume adjustments are then made after dcx, probably in the range -20db to -80db.

[Jim Griffin]

I'm a DEQX owner. It works as advertised and is highly recommended. While costly, it does much more than any other digital processor.

The DEQX exceeds the Behringer DCX in significant functions-- post digital processing volume control, filter processing power to correct time/phase/amplitude, and room correction/calibration functionality. The preamplifier version takes 4 inputs--two analog and two digital--and offers a remote control of input switching, parametric EQ and volume control. The hardware is top notch and very slick in usage.

The DEQX is totally measurement based with software doing the changes to settings versus the old click dials on pro audio analog crossovers. The software is easy to use but you do need to follow the process through to completion for best results. It is not a sit down and randomly make changes kind of process.

There is an active owners beta forum/mailing list wherein actual usage is discussed and new beta software versions are released.

A number of other message forums have users (try Madisound, Audio Circle, Audio Asylum, and others) who report on their experiences. Use their search features to find the messages about DEQX.

Jim