Digital crossovers - some info - long

[Ken L]

As an early adopter of the Behringer DCX2496 I made a post about my initial reactions and experiences and thought I would make a post about my current status and experiences.

I sold the Behringer and now use a BSS FDS366 Omnidrive Compact Plus which I bought used from an ad in one of the Pro forums.

When I changed from FE206e's to Lowther DX4's in the Azurahorns the greater efficiency of the Lowthers allowed me to hear a good bit of noise that I had not been able to hear with the FE206E's. I originally attributed it to the Behringer, but this was actually due to the signal level differences between consumer equipment and pro equipment.

I am now using a homebrew TVC control tube preamp that is a better match with the BSS unit and the combination is such that noise is no longer an issue.

The BSS FDS366 sounds better to my ear and performs quite well. The only negative about the BSS unit to me is a slight fan noise that is just barely noticeable, but not so much as to represent an issue to me. The BSS also has a 5db better signal to noise ratio than the Behringer. One feature that I am using that is unique to the BSS units is the NTM 56DB slope.

I was originally surprised that in my setup a 48DB slope sounds noticeably better than a 24DB slope, and the NTM 52db slightly better. I am crossing at 134 hz. Obviously, this might not be the best for other users.

Looking for info about what the pros think of the various units I spent a lot of time searching on the pro forums and communicated directly with some of the pros sound guys.

The absolute best tool I found was an Excel spreadsheet by Binkster at

http://www.binkster.net/DSP_list.xls

The spreadsheet is a tremendous tool for comparing features of various models and units.

The spreadsheet does not tell you how the units will sound and what has the better reputations among the pros, so I will share with you some general impressions I gleaned from my searching.

Generally, BSS is well thought of and one of the more prevalent pro units - other similar units that would be desirable include ( in a rough order of preference), Dbx Driverack 260 and up, Ashly Protea ,Klark-teknik, and at the top of the pro heap XTA

I bought the BSS because it was what came on the market at a good price – Assuming correct features, I would have bought any of the ones above as they are the ones more respected by the pros – Unfortunately, when sold used these tend to be sold as a part of a system and not as an individual piece so they can be hard to find used - I haunted e-bay and the used pro sources for a good while before finding the BSS unit – While the XTA units command the highest prices – and have a reputation for having better algorithms and sound – I believe you likely would be happy with any units from my suggestions above if you can find them used at a preferential price.

As far as I am concerned any of the above units you find will likely be suitable and I would have purchased any of the units above if I had been able to get a really good deal.

In the list, you will notice a lot of variables, such as 48kz or 96kz processor, etc. You need to pay particular attention to all the specs to ensure that a particular model is suitable to your application. However, I wouldn’t get too hung up in specs because one of the really important things to how these units actually sound is the proprietary algorithms used by the designer.

Some of the 48kz units command lower prices but have a reputation for sounding very nice - The Electro Voice units are generally well thought of in terms of how they sound. If an EV DX38 had come along dirt cheap, that is what I would be using right now although it is only a 48K unit.

If you don't mind doing your settings from a laptop or PC _and_ are running Win9X, an EV Merlin might be an excellent choice for someone on a tight budget. _After_ I bought the FDS366, I saw a Merlin on E-bay get no bids at $135. I think that particular model sold new for $2500.

Are deals hard to find? Yes!

Are they there? Yes!

If price doesn't matter, personally, I would go with a DEQX http://www.deqx.com/

I have posted this in hopes that the hours I spent researching will benefit others interested in this subject. I have not heard a single one of these units other than the two that I have owned. This is not meant to be an all inclusive list and your favorite may not be here and I don't wish to get into discussions about the accuracy of my list or which unit is better, etc. This is just a general guideline of roughly what I found on the pro forums and _my_ interpretations of the posts that I came across. Doubtless, others will have different opinions _really big grin_

While I am a great believer in digital crossovers I will warn you if you are going with a pro unit to do your homework on signal levels and impedance matching differences between consumer equipment and Pro equipment. However, not being a tech I will leave it for others more knowledgeable than I to explain _grin_

All standard caveats apply, YMMV, IMHO, Caveat Emptor, do your homework, etc.

Regards

Ken L

[timsch75]

Thanks for the tips. I'll be researching units for home audio, and it's nice to have a head start.

[GRollins]

A friend of mine bought one of those Behringer 8024 (?) 1/3 octave units with the intent to use it as sub EQ, and possibly as sub crossover via brute force programming of the graphic EQ if no other method was available.
And that was the last I heard of the matter.
Any time I ask him how he likes the unit, the topic slides away in another direction. I suspect that he doesn't like the sound of it, but doesn't want to admit that out loud. I've played with one for an hour or two, but not long enough to form a serious estimate of its sound quality. However, that couple of hours didn't exactly leave me with a burning desire to re-borrow one in order to play with it some more.
This isn't to say that some of the company's other products aren't standouts, and certainly isn't intended to reflect on pro gear. Just saw the thread passing by and thought I'd toss this in.

Grey

[Ken L]

Originally posted by GRollins
A friend of mine bought one of those Behringer ******.....
This isn't to say that some of the company's other products aren't standouts -

Behringer makes a DEQ2496 that they call the ultracurve pro which is an EQ unit that is well thought of in some quarters.

Behringers analog units do not generally have a reputation for sounding good, but some of the digital units fare better.

The Behringer units are built to a low price point and some of the digital units sound surprisiingly good for the money. You see little about Behringer on the Pro forums. My guess is that the Behringer does better in a light duty environment and the pros have concerns about it's holding up to the rigors of the road.

Generally, I have large concerns about adding another link to the chain, just for EQ - you're adding another adc/dac step, which is enough to make any purist cringe _grin_

Still, if you're bi-amping, you've got to use some sort of linelevel crossover - the additional benefit of EQ in a digital crossover can be very real with no additional penalty, since everything you do in terms of delay, slopes, gain matching, etc is all done in the digital domain.

I think that there will be more and more adopters of digital crossovers as people realize that the benefits easily outweigh the disadvantages. It's not as if passive components are perfect, either.

Regards

Ken L

[tubesguy]

Thanks for the post, and for the link, but after wading through the spreadsheet, I find that I still can't find the answer to my question.

So, is anyone aware of any commercial product that accepts digital in, does EQ and crossover in the digital domain, and outputs two (for a 2-way crossover) or three (for a 3-way crossover) digital signals?

I realize that right now the applications for such box may be few (in my case, I have two identical Panasonic XR10 receivers), but there must be some market for such a device.

Or is my only alternative a PC-based system?

TIA - Pat

[RobWells]

Grey,

I've got an 8024 and the newer deq2496 (ultracurve). The 2496 model is cleaner than the 8024. I blind tested both units to my wifes' ears, and she could hear the 8024 affecting the signal, but not the 2496 model..(she hears better than me)

The (newer)ultracurve works well with my dcx2496(xo) as it accepts 'home'levels, and then outputs aes/ebu direct to the dcx.

Rob

[dwk123]

Originally posted by tubesguy


So, is anyone aware of any commercial product that accepts digital in, does EQ and crossover in the digital domain, and outputs two (for a 2-way crossover) or three (for a 3-way crossover) digital signals?

Yes - the DEQX unit referred to earlier. www.deqx.com, or available in the US via www.e-speakers.com. It is the technology used in the upcoming NHT active digital speaker, although they use analog inputs. It'll run $3500 US with digital outputs.

I realize that right now the applications for such box may be few (in my case, I have two identical Panasonic XR10 receivers), but there must be some market for such a device.

Or is my only alternative a PC-based system?

TIA - Pat

As we've circled around countless times, a PC system would be cheaper but at the expense of time and effort. Another option to consider is to search here or on the DCX2496 user group for the info about someone modding their Behringer DCX2496 unit to add 3x spdif outputs. It's a technically straightforward but mechanically somewhat tricky mod.

[tubesguy]

Originally posted by dwk123
As we've circled around countless times, a PC system would be cheaper but at the expense of time and effort. Another option to consider is to search here or on the DCX2496 user group for the info about someone modding their Behringer DCX2496 unit to add 3x spdif outputs. It's a technically straightforward but mechanically somewhat tricky mod.

Ah, yes, I've read much of the circling. My question was really about interpreting the spreadsheet info that Ken posted, which is not self-explanatory with regard to the parameters of any digital output capabilities.

I did check the users group and found the phrase to search for Tanto's mod here at DIY. Exactly what I'm looking for, but far beyond the capabilities of my eyes, hands, and nerves. :-( Very cool, however.

DCX2496 mod for Digital OUT x 3

Thanks - Pat

[Ken L]

Originally posted by tubesguy
.....question was really about interpreting the spreadsheet info that Ken posted, which is not self-explanatory with regard to the parameters of any digital output capabilities......

The Pro crossovers that list digital in and digital out are usually designed with a good bit of flexiblity - Auditoriums, stadiums, large venues might readily use 30 or 40 or more of these linked together digitally and manage their settings through software -They can be linked together in a tremendous variety of methods.

Usually the digital out for a threeway out pro sound system is still only _one_ digital out - that digital out will be used to continue linking the devices for propagation of the signal and for settings - not for outputs per channel.

Originally posted by tubesguy

I realize that right now the applications for such box may be few ........ but there must be some market for such a device.

Or is my only alternative a PC-based system?

TIA - Pat

I believe you're probably five years or so ahead of the curve _really big grin_ not really much market penetration along those lines at this point in time.

Not sure I understand _exactly_ what you want to do - but if TACT and DEQX don't do it, you're looking at a PC based solution -

Regards

Ken L

[JinMTVT]

This is some seriously nice information,
thanks to all the posters

I've been going through the DEQX faqs and all ..thinking about how i could use such a system in my life.

The problem i have here, is that for this system to work at its best, u need to use separate amplifier for each different drivers system. This is not in itself a bad thing, and i guess that it is the only way to achieve a near perfect control of every aspect,
it though brings the $$$ in the line.

Let's say that someone is using DIY loudpseakers,
LA with multiple drivers + a sub filling the low hz part.

U need an amplifier for the wooofers, and amplifier for the tweets
and an amplifier for the sub.

I personally don't settle for anything less than Bryston
wich is what i have right now,
and at the price we pay for an amplifier, the budget is going over top pretty quickly.

Too bad i already have a recent 4B, and i can't afford a second one for now ahhaha

As this DEQX system , going diitally IN from my PC wich is the center of all my source, would be the way to go, no need for expensive computer sound card since the DACs on that thing are supposed to be up good ( i sure hope so at 3000$+ USD )

but using digital, it means that there is almost no loss in quality,
could we say none ? from the source to the EQ passing in the crosovers, and that each driver set are controlled to perfection and independantly adjustable to whatever needs?

do you guys think that a digital eQ/crossover unit such as this one,would be of any benefit if the system is to be more than 1 way ( + sub )

neway all in all, my planned system is a pair of ELS for mid+
and a dipole array of 12-15" for woofer/sub , so i guess that using digital crossover/eQ wouldn't be of any problem on this 2 way 2 stereo amplifier system ?

I am still on the lookout for a PC SOFTWARE based EQ/crossover system that could be set just before DAC of most sound cards!
even if it would use much cpu ressource
( would get a dual even if needed..mmm dual amd 64 haha )

i do not konw much about audio softwares inside computer,
but i sure know that there is a possible way to use a sofware to alter digital sound before it is output to the DACs of the cards!!

what do you think ?