Vadim
Good review of the product. As low cost products go this looks to be a good buy. It does offer a bunch of features for the price. Still, I would not want to put the unit on the tail end of my audio systems.
I believe that most of the features in this unit belong in the DAC. So if we could start with a clean sheet of paper there no reason why ARC and multiple digital filters could not be added. We could then use support multiple DAC’s for a three way systems. Having said that, maybe there a way to integrate the logic of the DCX2496 with the DAC to improve the performance. Can you get a schematic for it.
Good review of the product. As low cost products go this looks to be a good buy. It does offer a bunch of features for the price. Still, I would not want to put the unit on the tail end of my audio systems.
I believe that most of the features in this unit belong in the DAC. So if we could start with a clean sheet of paper there no reason why ARC and multiple digital filters could not be added. We could then use support multiple DAC’s for a three way systems. Having said that, maybe there a way to integrate the logic of the DCX2496 with the DAC to improve the performance. Can you get a schematic for it.
FYI: I note the DCX2496 may need a format converter sometimes from S/PDIF to the AES/EBU input. Looks like sometimes just a physical adapter will work.
From a link on main info page for the DCX2496 on the Behringer site:
>Can I send a standard S/PDIF signal from a consumer device (for example a CD player which uses an RCA coaxial connector), to the XLR input on the DCX2496 ?
>Yes - under most normal circumstances this will work. The two transmission standards are similar but not identical - you may find that under certain circumstances the AES/EBU input to the DCX2496 does not automatically recognise the SPDIF signal coming from the consumer device. This is due to the physical properties of the SPDIF transmission, and is not a defect in the DCX2496. The best solution to this situation is to use a universal format converter - eg our SRC2496. However, if you do decide to use an adapter cable it is important to use a cable which is suitable for digital data transmission
From a link on main info page for the DCX2496 on the Behringer site:
>Can I send a standard S/PDIF signal from a consumer device (for example a CD player which uses an RCA coaxial connector), to the XLR input on the DCX2496 ?
>Yes - under most normal circumstances this will work. The two transmission standards are similar but not identical - you may find that under certain circumstances the AES/EBU input to the DCX2496 does not automatically recognise the SPDIF signal coming from the consumer device. This is due to the physical properties of the SPDIF transmission, and is not a defect in the DCX2496. The best solution to this situation is to use a universal format converter - eg our SRC2496. However, if you do decide to use an adapter cable it is important to use a cable which is suitable for digital data transmission
jewilson,
Definitely it is an interesting and not particularly complicated project to fit the DCX with multiple SPDI/F transmitters and take the signal outside where you can do with them anything you want. Also, I agree that it is better to design the DCX-like features into a CD-Player so that only one D/A conversion takes place. Naturally that would be ultimately the most elegant solution.
However, we are living in the real world, and consequently most people need a stand-along gear that can simply be inserted into the existing signal processing chain. The DCX is responding to that need. It is small, self-contained and very high performance.
Again, although it is somewhat counter-intuitive, but I still maintain that there is no penalty in THD when you use the DCX as an ‘analog in-analog out’ device. Also, it does have AESBU digital input, so it is very doable to use it with a common CD Player once you convert the SPDI/F into AESBU. This conversion will set you back about $100 with no audible penalties.
The difficulties in using the DCX arise from the need of a multi-channel volume control and also one must ensure that the analog input level is at least 8-9 Volt. I did that when I tested the DCX.
My solution to an inexpensive multi-channel volume control was to get 10 Alps linear motorized pots from http://www.allelectronics.com/cgi-bin/category.cgi?item=MPOT-10K for 3.50 each. I then turned them into log pots by paralleling 1.5 kOhm resistor with the output. This ensures the nearly perfect tracking pot to pot.
I then hooked the motors together to a single motor control circuit with infrared control capability. In the end I could control 10 pots with a universal hand-held remote. I had to insert 1-2 Ohm resistor in series with some motors in order to equalize the rotational speed. Consequently all pot would turn simultaneously and together.
I also used a relay circuit to be able to select any or all pots before I activate the motors. So, it is kind of like a Master volume and balance control. My implementation served 8 channels in my HT Room.
Vadim
I do not have the schematics of the DCX, but I sure would like to get one. From experience I know that the A/D and the D/A implementation in the DCX is a cook-book, i.e. it is as standard as it can be. So perhaps we can extrapolate from here and figure things out.
Definitely it is an interesting and not particularly complicated project to fit the DCX with multiple SPDI/F transmitters and take the signal outside where you can do with them anything you want. Also, I agree that it is better to design the DCX-like features into a CD-Player so that only one D/A conversion takes place. Naturally that would be ultimately the most elegant solution.
However, we are living in the real world, and consequently most people need a stand-along gear that can simply be inserted into the existing signal processing chain. The DCX is responding to that need. It is small, self-contained and very high performance.
Again, although it is somewhat counter-intuitive, but I still maintain that there is no penalty in THD when you use the DCX as an ‘analog in-analog out’ device. Also, it does have AESBU digital input, so it is very doable to use it with a common CD Player once you convert the SPDI/F into AESBU. This conversion will set you back about $100 with no audible penalties.
The difficulties in using the DCX arise from the need of a multi-channel volume control and also one must ensure that the analog input level is at least 8-9 Volt. I did that when I tested the DCX.
My solution to an inexpensive multi-channel volume control was to get 10 Alps linear motorized pots from http://www.allelectronics.com/cgi-bin/category.cgi?item=MPOT-10K for 3.50 each. I then turned them into log pots by paralleling 1.5 kOhm resistor with the output. This ensures the nearly perfect tracking pot to pot.
I then hooked the motors together to a single motor control circuit with infrared control capability. In the end I could control 10 pots with a universal hand-held remote. I had to insert 1-2 Ohm resistor in series with some motors in order to equalize the rotational speed. Consequently all pot would turn simultaneously and together.
I also used a relay circuit to be able to select any or all pots before I activate the motors. So, it is kind of like a Master volume and balance control. My implementation served 8 channels in my HT Room.
Vadim
AES/EBU and SPDIF
moving_electron,
The SPDIP and AES/EBU interfaces are quite similar, the AES/EBU is a 110ohm and balanced where the SPDIF is unbalanced and 75ohm.
Here some decent info on digital audio interfaces.
http://www.mtsu.edu/~dsmitche/rim420/materials/Interface.html
It is possible to convert one to the other also. However it is very important that the interface be low jitter and good impedance match is made between the two.
---------------------
Vadim ,
I have seen these unit for sale on EBAY, however I'd like to know what types of DSP they are using. Also, I would not use their DAC I would use a Burr Brown DAC like a PCM1704. So they have to have some kind of standard digital interface for the DACs.
Since they have, an AES/EBU interface what kind brand of receiver chip or they using. It may be possible to replace the receiver with a CS8420 and up sample at before the DSP.
moving_electron,
The SPDIP and AES/EBU interfaces are quite similar, the AES/EBU is a 110ohm and balanced where the SPDIF is unbalanced and 75ohm.
Here some decent info on digital audio interfaces.
http://www.mtsu.edu/~dsmitche/rim420/materials/Interface.html
It is possible to convert one to the other also. However it is very important that the interface be low jitter and good impedance match is made between the two.
---------------------
Vadim ,
I have seen these unit for sale on EBAY, however I'd like to know what types of DSP they are using. Also, I would not use their DAC I would use a Burr Brown DAC like a PCM1704. So they have to have some kind of standard digital interface for the DACs.
Since they have, an AES/EBU interface what kind brand of receiver chip or they using. It may be possible to replace the receiver with a CS8420 and up sample at before the DSP.
moving_electron said:
If you're lucky, you can get away with one of these, which is just a 110-to-75 xformer.
http://www.markertek.com/SearchProduct.asp?item=NA-BF&off=44
If you need actual format conversion, you'll need one of the more advanced boxes. Since there seem to be a fair number of folks around that are feeding the dcx digitally, I'd imagine that the xformer should work in most cases.
Re: AES/EBU and SPDIF
Jewilson,
Here is the main info thread on the DCX2496.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=15943&highlight=
First, as you can see in the hi-res photo on the first page, there is already an 8420 on-board. Second, they're using SHARC dsp's, although I don't remember the specific model. The DAC's are AKM 4393's, which are pretty decent chips, although the power supply and analog output stage might be holding them back in the Behringer.
Is there anyone that is considering actually tackling an spdif xmitter mod? I've been doing a fair bit of work on PC-based FIR filtering, but I simply don't have the free/spare time to get my project where it needs to be at the moment. I'm seriously considering a DCX as a stopgap, but NEED at least one spdif output since I'm using the Panasonic digital receivers as my 'amps', and they really require a digital input to sound decent. If there was someone else out there to share info/experience with, it might make me more comfortable jumping into the project.
jewilson said:
Jewilson,
Here is the main info thread on the DCX2496.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=15943&highlight=
First, as you can see in the hi-res photo on the first page, there is already an 8420 on-board. Second, they're using SHARC dsp's, although I don't remember the specific model. The DAC's are AKM 4393's, which are pretty decent chips, although the power supply and analog output stage might be holding them back in the Behringer.
Is there anyone that is considering actually tackling an spdif xmitter mod? I've been doing a fair bit of work on PC-based FIR filtering, but I simply don't have the free/spare time to get my project where it needs to be at the moment. I'm seriously considering a DCX as a stopgap, but NEED at least one spdif output since I'm using the Panasonic digital receivers as my 'amps', and they really require a digital input to sound decent. If there was someone else out there to share info/experience with, it might make me more comfortable jumping into the project.
dwk123,
well crystal make a transmitter using a CS8414, I don't believe that would be had to implement. After looking at the link you provided you can bet that the analog power in this unit is not up to par for the audio.
I guess for me to get interested in this kind of project I would have to get hold of they manual. The Analog Device Shark is a low cost DSP and the development tool are much cheaper than the TI DSP tools. The made a bunch of different version and I’ am not up on their current DSP’s.
So does the DCX2496 unit use for a controller, also I see that the unit support a PCIMCA slot is that for programming of add-on's.
well crystal make a transmitter using a CS8414, I don't believe that would be had to implement. After looking at the link you provided you can bet that the analog power in this unit is not up to par for the audio.
I guess for me to get interested in this kind of project I would have to get hold of they manual. The Analog Device Shark is a low cost DSP and the development tool are much cheaper than the TI DSP tools. The made a bunch of different version and I’ am not up on their current DSP’s.
So does the DCX2496 unit use for a controller, also I see that the unit support a PCIMCA slot is that for programming of add-on's.
QX
The combination of the Behringer DEQ and DCX together is a affordable combination that can do a lot and is a good introduction into the world of DSP. They are pretty flexible and once one gets up the steep learing curve and tries using fast slopes, time alignment, room EQ, Etc., one realizes a new world of push button changes. There are some issues with integrating these into a home audio system since variable ouput isn't an option, but if you can get it integrated it is probably a step up for most systems with passive crossovers (assuming equivalent quality amps are used). I did some auditioning of the unit as a DAC, using 1 of the 3 outputs straight through, it sounded OK and mainly can be faulted for omission rather than adding artifact. I used the combo for about 5 months in triamp and ultimately moved on to the DEQX PDC 2.6, with the digital out option (balanced and unbalanced) The DEQX is a lot more money than the Behringer DEQ and DCX combo but I felt it was worth it for the improvement in sound quality. When I first got the DEQX, I listened to it in analog out and feel it sounded (and sounds) better than the Behringer equipment, (more information, better sense of low level dynamics, more individual instruments could be noticed and better soundstage, like a veil was lifted, to re-use a often used phrase). Having digital out and using it into the digital inputs on 3 modified Panny XR-45's was the next step up. I wanted a digital out option and looked at modifying the Behringer DCX, it is do-able, but would involve building a board for required interface chips, buying about $140 in parts and it would take a bunch of time (and require really good eyes to solder wires to the really small through holes at the inputs to the 3 DAC's). It was just a lot easier to go to the DEQX. I'm a CD only guy so never tried out the analogue in on the Behringer, so can't comment on that. Hope this input helps anyone looking at options. The DEQX is designed for high end audio with phase linear crossovers, slopes up to 300 DB/octave, phase and time alignment etc, the Behringer stuff is designed more for people running a sound board, but is probably an improvement in a lot of systems over passive crossovers. My speakers are home built open baffle (in the midrange) line arrays using 8 5.25" seas excel drivers and a 45" newform research ribbon per side, they pretty much reveal everything upstream. Roger Vale
The combination of the Behringer DEQ and DCX together is a affordable combination that can do a lot and is a good introduction into the world of DSP. They are pretty flexible and once one gets up the steep learing curve and tries using fast slopes, time alignment, room EQ, Etc., one realizes a new world of push button changes. There are some issues with integrating these into a home audio system since variable ouput isn't an option, but if you can get it integrated it is probably a step up for most systems with passive crossovers (assuming equivalent quality amps are used). I did some auditioning of the unit as a DAC, using 1 of the 3 outputs straight through, it sounded OK and mainly can be faulted for omission rather than adding artifact. I used the combo for about 5 months in triamp and ultimately moved on to the DEQX PDC 2.6, with the digital out option (balanced and unbalanced) The DEQX is a lot more money than the Behringer DEQ and DCX combo but I felt it was worth it for the improvement in sound quality. When I first got the DEQX, I listened to it in analog out and feel it sounded (and sounds) better than the Behringer equipment, (more information, better sense of low level dynamics, more individual instruments could be noticed and better soundstage, like a veil was lifted, to re-use a often used phrase). Having digital out and using it into the digital inputs on 3 modified Panny XR-45's was the next step up. I wanted a digital out option and looked at modifying the Behringer DCX, it is do-able, but would involve building a board for required interface chips, buying about $140 in parts and it would take a bunch of time (and require really good eyes to solder wires to the really small through holes at the inputs to the 3 DAC's). It was just a lot easier to go to the DEQX. I'm a CD only guy so never tried out the analogue in on the Behringer, so can't comment on that. Hope this input helps anyone looking at options. The DEQX is designed for high end audio with phase linear crossovers, slopes up to 300 DB/octave, phase and time alignment etc, the Behringer stuff is designed more for people running a sound board, but is probably an improvement in a lot of systems over passive crossovers. My speakers are home built open baffle (in the midrange) line arrays using 8 5.25" seas excel drivers and a 45" newform research ribbon per side, they pretty much reveal everything upstream. Roger Vale
planet10 said:
I certainly respect your choice but is there anything recent?
One reference is to a 1992 case. The other is related to an R&D mockup. (By law patents can be violated for R&D and educational purposes as long as the final product complies so using a PS design to power a demo seems well within ethical behavior.).
Blatent copying of a full design artwork is of course unethical and illegal in many circumstances as evidenced by the 1992 case which presumably covered something in the 1980. I agree such a product should be avoided. An example is some of the products touted as exact Pass Labs copies.
But what is the DEQ2496 or the DCX2496 H/W and software a copy of?
I would not like to see a world where no idea or implementation ever gets used or manufactured by a competing company. Historically there is a balance some where in the middle.
Or would you rather have no aftermarket automobile replacement parts? Do your clothes only come from the original designer of a style? Do you seek out PC's without VIA components. Have you historically only bought PC's from IBM?
Re: Re: QX
"Similar kit" is the DBX Driverack PA.
It is very close to the same specs in terms of what it does. Includes a rta, but doesn't do auto-delay, IIRC.
There are differences between the units but they are _very_ similar.
Can be found new for about $75 to $100 US _more_ on E-bay "buy it now" than a DCX2496.
Regards
Ken L
planet10 said:
"Similar kit" is the DBX Driverack PA.
It is very close to the same specs in terms of what it does. Includes a rta, but doesn't do auto-delay, IIRC.
There are differences between the units but they are _very_ similar.
Can be found new for about $75 to $100 US _more_ on E-bay "buy it now" than a DCX2496.
Regards
Ken L
Vadim said:
Your posts have been excellent so far, extremely informative. I must ask, how would I reach an analog input level of 9 volts using a standard home theater pre-amp? In my particular case, a Rotel RSP-1066 which is only rated at 1.2 volts pre out, I would need to increase significantly to say the least. Assuming a lower input voltage of 1 volt, what penalties should I expect to pay if I choose to use the DCX as the crossover for my new stereo monitors?
moving_electron said:
I happen to know that much of the DCX design work was contracted for by Behringer to a company I know - so it seems to be an original work.
I also am somewhat sceptical about large scale copying of PCB boards with logo's and all. How is this supposed to happen? Xerox an original board? Or were the original manufacturers, who are now complaining, the ones that sold large amounts of boards to Behringer?
1992 court case? It is not uncommon (in fact, it seems the rule) that after a court case both sides would claim victory.
Without both sides of the story, I would not let this type of mudslinging influence my buying decisions.
Jan Didden
Re: My evaluation results DCX2496
Hello Charly,
This is great work !
I also have a DCX2496, ECM800 and slightly bigger Quadral (Titan MkIII)
However, I have been much faster for adjusting the Xover (hence my admiration for your work) by enquiring with Quadral designing engineer Georg Stracke, as he is responsible for the Titan/Vulkan design - see emails below.
I already knew the Quadral Titan passive crossover frequencies : 320Hz and 4kHZ. And also that an attenuation had to be applied to the midrange and tweeter relatively to the woofer (respectively -9dB and -6dB). That's because when I bought my Titans in 1987 (new) I already asked those specs to Quadral (I wanted to step in active amplifiaction right from the start, but couldn't afford an active Xover and 6 amps. The DCX has allowed this for very little money !)
I would be interested in exchanging DCX's parameters files with you as we have very similar loudspeakers.
Thierry
Here's the story
First email to Quadral :
In english now ((sorry, I used Altavista Babelfish)
Reply from Quadral :
In english :
oehlrich said:
Hello Charly,
This is great work !
I also have a DCX2496, ECM800 and slightly bigger Quadral (Titan MkIII)
However, I have been much faster for adjusting the Xover (hence my admiration for your work) by enquiring with Quadral designing engineer Georg Stracke, as he is responsible for the Titan/Vulkan design - see emails below.
I already knew the Quadral Titan passive crossover frequencies : 320Hz and 4kHZ. And also that an attenuation had to be applied to the midrange and tweeter relatively to the woofer (respectively -9dB and -6dB). That's because when I bought my Titans in 1987 (new) I already asked those specs to Quadral (I wanted to step in active amplifiaction right from the start, but couldn't afford an active Xover and 6 amps. The DCX has allowed this for very little money !)
I would be interested in exchanging DCX's parameters files with you as we have very similar loudspeakers.
Thierry
Here's the story
First email to Quadral :
In english now ((sorry, I used Altavista Babelfish)
Reply from Quadral :
In english :
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