Kill your DCX!!! or sell it at least. . .

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Hi-

I had alot of help building my studio mains here a while ago and I was one of the many people using a behring dcx xo- I just wanted to let you all know that I found a much, much better way!!!

If you are like me and you have a computer sitting around (in an iso box of course) you can make a much better XO using a asio capable soundcard and a free or cheap asio host. On my studio monitors I went from being able to hear a 2dB boost or cut on an EQ accross all bands (of a master) to being able to hear a .5dB boost/cut- And it sounds better and the speakers are easier to tune and flatter.

Oh- if you don't need real time playback you can use FIR filters, you will get a 60-100ms delay- they didn't sound noticably better to me so I stuck with some other ones (and i do need the turn around latency to stay as low as possible) Anyway thanks guys-

Ryan
 
diyAudio Member
Joined 2004
m0tion said:
I can only assume you are refering to the kxproject.

An Audigy based card is required for KXProject and whilst it has ASIO drivers, Ryan states that the system he uses just requires an ASIO card. So hopefully it isn't the KXProject he's referring to.

I'm certainly interested in this as I personally find the Audigy cards to be quite inferior to the RME that I use. If its possible to do this through the RME then I will be a happy chap.
 
I'm still looking for the holy grail: an all-digital path that accomplishes a three-way crossover. Digital in > crossover and EQ > multiple digital outs > multiple Panasonic digital receivers, all with volume control from one remote. I don't care if it's a box (modified DCX would be fine, but I can't do the job myself) or a computer, but I'm still looking for an affordable solution. - Pat
 
alll digital to where?
I run cd player to src - deq - dcx(2496) to two six gang pots to amps.
You can also run cd to dcx and then via pots to amp.
This computersolution might be ok for studio or if you run your cd collection via harddrive, other than that i think its a cumbersome solution.
 
CD collection on hard drive > iTunes > Airport Express > digital out. Since it's all digital to that point, I can't see doing a digital to analog conversion until I have to. With dual or triple Panny or other digital receivers, you bypass any analog interconnects and analog volume control.

If I want analog, I can always play vinyl via the Vendetta. This thread is about digital crossovers, however. - Pat
 
This thread is about digital crossovers, however

Right, and my solution via standalone units is digital right up to the pots - sure, could make them digital, but does it matter? to go to the power amps i have to convert after the xover anyway.
With the src i also convert analog to digital before i enter the sound processing chain.

Except as in your case, i still think that stand alone digital xovers are more convenient.
 
I guess it's a bit too much to ask for the original poster to have dug up one of the many previous digital xover threads that have been started (although none has been active for a while, so I guess we were due).

I'll echo the idea that using a PC for digital xovers is nothing new. There are a fair number of folks doing FIR filtering under Linux with BruteFIR, and there are a couple packages like AsioXO and the Foobar xover plugin for Windows. I'm a big advocate of this approach, and I do think it can approach the absolute state-of-the-art for relatively modest investment.

However, it's inconvenient, time consuming, and filter generation is far from an easy task. I think we're all still waiting for a really accessable package that 'just works'.

Having just picked up a DCX myself, I have to say that after about 2 hours with SoundEasy and the DCX I had something with my prototype horn speakers that was about as good as anything I had come up with via either Foobar or Brutefir. Sure, the DCX isn't the ultimate, but it's good, it's cheap, it's pretty easy to use, and when coupled with a DRC generated room correction filter, I bet it's 75-80% of what you can do with the most advanced DSP you care to throw at the problem.

In other words, it's a great stopgap while you get the 'real' approach going.
 
Um, I think in my original post, I said standalone or computer, I don't care which. I'd actually prefer, in fact, a standalone solution, like this:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=36252&highlight=

I just don't have the ability to do the mod myself.

As to the benefit of where you do the digital to analog conversion, if you guys don't mind, I'll just go with my choice. You are, of course, free to make your own. :) - Pat
 
I've been following this for a while and I know its nothing new- I just switched and the difference was phenominal- even my girlfrind was impressed!!! I will explain how my setup is working- I'm not stating that I am the first to do this at all and it may not work well for everybody. But it sure as hell works great for me!!

BTW- I am not using the KX thing and I wouldn't waste my time with any of those soundcards over the better stuff available.

This is for a recording studio- I have a MOTU 1296 and 2408mkIII wich is my main IO source for the studio (www.motu.com). I am using an older version of cubase sx as my asio host, but you could use a cheap hoast like chainer just fine- I still had the old dongle when I upgraded so I am using cubase- however I own chainer too and I might redo it with that (a bit less flexible but good still)

My setup- I have a RME digi 9652 (26ch Digital audio PCI card) in my main recording PC (dual 3.6GHZ xeon) and I have a second "office" type computer for CD burning email etc- The MOTU 424 pci card resides in this computer- I have it setup this way because the RME drivers are alot more solid for recording etc and they provide ASIO2 drivers wich carry WC signals to the hoast (in my case Nuendo) much better than motu drivers-

OK so - asio drivers are steinberg's (maker of cubase and nuendo's) kernal level audio drivers- you could use WDM drivers or even MME if latency is not an issue and any host with directx or vst plugin support should work just fine (cubase, sonar, nuendo, chainer the JP plug hoast thing etc). Or you could use AU on a mac-

Then all these hoasts are able to live monitor the input of the signal- so I have AES/EBU on my 1296 input set to monitor (my 9652 has spdif out but it will drive a 110ohm load when you check the "professional" box), This essentially makes the computer a "stand alone box"

then I create 3 aux tracks in cubase and name them bass,mids,hi's then assign track one (the monitored one) to the three auxes all at 0dB (or whatever as long as it is the same) then you can use any directx or vst plugins to create your XO- I am using the waves Q10 witch gives me 10 eq bands per XO band- the only prob with it is the HP LP filters are fixed Q so you have to combine several to make a steep slope- you can also use parametric lower Q bands to further attenuate MF and HF in the sub band for example- this helps alot with metal cone sub drivers like mine- Cool enough- my mids- audax aerogels - don't need an XO at all, so I just have a bit of tuning and a HP filter to minimize IMD.

The beauty of this setup is you are not tied to anything - you can upgrade converters, EQ algos,sample frequency etc- hell, you could get a Lavry 6ch DA and listen through some of the best converters made (for about 4k!!) Or do it all at 192k Or use the mykerinos board/software for an all DXD XO (for about 10K W/O DA's!!!)- and upgrade it bit by bit over the years - also you can have a low latency IIR setup for movies or temporally sensative events and have a FIR setup for music where it really doesn't matter if it waits 100ms to start playing- unless you can rig a way to delay video playback- for me I need real time total latency under about 10ms for playing midi (piano/keys) parts.

I think the DCX mod looks cool and definitly sounds better than stock- but you are still tied to the EQ algo's in the box- and they are just default SHARC algos- not bad, but not the cream of the crop either (I used creamware cards for years so i am very familiar with them)- Also I can't quite tell how he's doing it all but it seems that you are tied to whatever ref clock they use in that thing-

SO in short- You can use any kernal level audio card that you like- In my experience ASIO is better for low latiency applicatiions then WDM and the best PCI cards at the pro level are made by 2 companies RME and Lynx, lynx ultimatly being the direction I am working toward- these are not cheap! but the 2I 6O lynx2b would make an excelent choice for this application (www.lynxstudio.com) this is what I will probably do eventually when I get rid of the MOTU crap. Rme is very good as well- you will need a good card b/c bad ones can be proned to clicks and pops- and you will need a mobo that has a good PCI bus- (I usually use asus boards for that reason). You don't need a slammin PC- a 1GHZ p3 will easily handle a 3 way IIR or FIR setup.

Then any vst host that supports routing one source to multiple destinations will work- however I would recomend using one that has ADC automatic delay compensation (cubase sx or nuendo on pc logic 7 or DP 4.5 or above on mac) this means that you can use more than one plug per channel and assure that you get perfect I to O phase allignment. You can also use a delay with the mix set to 100% wet for phase allignment (im still looking for a good plugin that goes to 100ths of a millisecond)

I'm not claiming that this is cheaper than the DCX and I liked my DCX for what it is- but I can tell you that the switch from it to better algos and better DA's is huge! I do think that this is ultimatly the best solution - not to mention that you are in no way tied to a 3 way system- a typical 2GHZ ish modern computer can easily handle duties for a 32CH system - and I believe that one of the best options would be to use a UAD (www.uaudio.com) card with the cambridge EQ's to make a killer XO (and at 96k it could remain below 3ms or so on a good single proc system)- Anyway these days it makes sense to have a good HTPC anyway - and my XO takes about 2% of my barton 2500+. I would recomend a PVC (i just got the SPL one) or some way to protect your tweeters (I have a cap for a passive HP filter on my founteks too). Different cards might pop or click when turned on or when the clock source changes.

OH BTW my system is the bigger founteks- audax aerogel 8 mids and TC2+ 12''s- The founteks and the audax's are driven by EV 7100's and I have a crown K2 for the tc2+'s- After frying a 4bst I wanted to use pro audio amps for the built in protection features. Also one other thing I have to say is that the better DAC's (with better clocking) drive your amps/speakers better- The TC2+'s are quite a bit happier with this setup- In my experience bad converters and especially bad SC or wordclock will result in peak abnormalties that cause your drivers and amps to work harder- this is a fundamental flaw with the DCX (it just activates the SRC for digital input and therfore has to mesh that signal with it's own free running clock, i believe) so it never has a great clock source. The reverse is also true at AD- EG a good (or bad) converter with a bad clock (eg Jitter) will result in a peakier recording of the same source- I'm guessing the DCX has a PLL clock chip that cost's less than a buck - not exactly hifi- especially in their implementation.

My cabs are about 200lbs and as long as you sit in the "spray" of the tweets the imaging is increadible! It's even a bit scary on great recordings- goosebumps and neckhair territory (never quite got there with the DCX- sound=good, imaging= ok-ish - and I probably listen to music about 40hrs a week so I am usually pretty jaded to that type of stuff.

DWK123: For easy FIR filters the waves LinEQ plug's are a hell of a lot easier than coding linix (www.waves.com) but they do have a 65ms turn around time, and they are not cheap, however you can snag a waves native masters bundle on ebay from time to time for not too much. I'm still not completely sold on FIR because of the curve abnormalities (and the latency)- I'm looking for a way to find a parametric phase shifter- then you could have normal curves, and near perfect phase. Also- sorry I've followed this on and off for a long time, but if you check out they way I'm doing this- it is easier to setup then a DCX and I believe a bit different then other methods proposed here. I have seen the FIR media player thing to- cool but would not work at all for me.

Tubesguy- I think good refclock is more important than that. I can state from experience that the only way to assure good clocking is to use an internal solution (eg all in one system) or a wordclock based system- slave over spdif/adat/aes etc is not the best option here- only a dedicated clock cable carries a ture clean master reference to the DAC's- this is absolutly critical for Hifi digital audio. In my view WC and the way it is handled in a digi system is paramount to all other concerns (i have extensivly compared the differences here)- 2nd only to the quality of the buffer stage and 3rd the actual quality of the AD DA chip (unless we are talking total crap here) this is why 6 year old apogee AD8000se's still fetch a pretty penny on ebay even though the crystal AD's and DA's are dated now. This is also why the EMU cards don't get me too excited- good chip, cheap buffer, cheap clock.

audio-kraut- Asio IO cards come in any possible flavor- You could easily get one with spdif in and analog out's- or one with MADI IO- I believe that this does not have to be more combersome than a DCX other than coputer fan noise. And it is much easier to setup than using the DCX front panel or over serial cable. Also FWIW I think that digital gian control is not a good idea unless it is properly implemented- your better of with pots.

Also understand that my setup would not work for direct play of a CD on the computer (or mp3 or whatever), to do that you would need 2 sound cards- In my opinion the best would be to get a "pro" CDR or CD player that has a WC input, then slave it to the computer (Lynx2b would be the best price/performance) and interconnect with AES cables- the good news is that most AES devices can drive 100's of feet of cable, so you could possibly use the family dell if you wanted to.
Thanks guys-
Ryan
 
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