D-OXO and the Digilog Adapter for SDE Speakers

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Brian Cheney

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D-OXO and the Digilog Adapter for SDE Speakers
« on: 25 Dec 2008, 08:02 pm »
Here are some general tips on adding the Digital outboard crossover (Modded Behringer DCX2496) to your system with minimal disruption.  Together with the Digilog Adapter (jumper) you can switch from analog to digital operation and back again (biamping will be required in both cases).

!. Analog to Digital with the outboard crossover (OXO):
Speakers with outboard crossover boxes (V60 is standard this way) can make the switch to SDE operation easily.  Locate the Digilog adapter (jumper with bananas at one end and bare wire at the other).  If you don't have such you can make one from a 2ft twisted pair of 16 or 18 gauge speaker wire, and soldering banana plugs to one end of the wires only.

Pull the OXO as far away from the speaker as possible and disconnect the BASS and MIDRANGE wires (out of the OXO) from the main cabinet.  Do not detach the TREBLE wire leading from the OXO to the main cabinet.

Detach the BASS and MIDTREBLE speaker wires (coming from your two amplifiers) from the OXO.  Hook the BASS wire from the bass amp to the BASS input on the main cabinet.  Hook the MID/TREBLE wire from the mid/treble amp to the MIDRANGE input on the main speaker.  Now attach one end of the DIGILOG adapter to the MID/TREBLE binding post on the main speaker, where the wires from the mid/treble amp are now also attached.  Insert the banana plug ends of the DIGLOG adapter into the MID/TREBLE inputs of the OXO.  This will supply a signal to the TREBLE output of the OXO which is still connected to the main speaker.  The tweeter level control will still work and you should use it to balance the treble level during digital operation of the speaker, which is easier than trying to do same via the D-OXO settings. At least 1dB of treble cut is recommended, which amounts to a 4 o'clock or lower setting of the control.  Note the midrange level control is out of the circuit, as is the bass and mid passive crossover.

To return to analog operation, reverse the above steps.

2. Setting BASS levels on the D-OXO.  If you are biamping with identical amplifiers
you can use the bass gain setting from the factory.  If you are using different amps with different input sensitivities you will have to adjust the bass gain settings of the Behringer by going into the program.

Push the SETUP button and then the PAGE buttons until the GAIN screen for inputs 1 and 3 comes up.  (Note: make sure you do not change the ROUTING settings, which should be LHLHLH) Press the CH 1 button under the righthand side LED display.You will see that the GAIN setting for inputs 1 and 3 is higher than for inputs 2 and 4, as boost is required to match bass levels (lower due to lower sensitivity of the bass section relative to the mid/treble).  Once you have highlighted the GAIN setting with the PARAM buttons you can adjust the gain by turning the wheel to the left or right.  You can match levels by ear but it is very important for maximum clarity and definition to go slowly, in 0.1dB steps.  Do this with several familiar recordings until you are satisfied the setting is correct.

Normally the bass gain runs 4 to 6dB higher than the mid/treble, depending on taste.  Feel free to experiment.

Contact the factory if you have questions about any settings.  Read the Behringer instructions carefully as there are many options available which the factory does not address, such as the DELAY settings.


Housteau

Re: D-OXO and the Digilog Adapter for SDE Speakers
« Reply #1 on: 2 Jan 2009, 06:28 pm »
 :thumb:
« Last Edit: 12 Mar 2013, 01:05 am by Housteau »

Housteau

Re: D-OXO and the Digilog Adapter for SDE Speakers
« Reply #2 on: 12 Mar 2013, 12:22 am »
It was suggested that the drawing from my post in the main section of this forum be added to this one here since it shows what Brian is describing and it will remain 'Stickied'.  I think that was a good idea John.  To help with the explanation I thought it best to include the entire post and not just the drawing.



There have been several people interested in going digitally active with the Behringer DCX 2496 for their speaker systems and I thought this post might help as a guide.  I have the RM-V60s with flanking VLA bass towers.  My system was originally set up for passive multi-amping using the included external analog xover.  Once making that change over to the DCX I could never imagine life once again without it.  I did have my concerns in the beginning though.  I mean how could such a cheap non-audiophile industrial unit possibly sound reasonable, let alone vastly improve anything?

What sold me was Brian's enthusiasm for this unit.  He did a lot of critical listening through it with the end results being that he found it extremely transparent when using the analog inputs.  He mentioned that whatever ill effects there may be they were greatly outweighed by all the positives that unit could provide.  There were discussions on this forum at the time about this, because how could it sound better for a digital source to be converted to analog first and then back to digital through the DCX, just to be converted back to analog once again for the output?  Wouldn't it be better to keep the signal digital going in to the DCX and just have one conversion to analog for it's output?  That does seem technically more logical. But, as with many things audio, listening tells us the true story and is the only one that has any real merit. 

Personally I go analog in as well and do not like the digital in, even though my unit has been highly modified with that digital section improved over the stock version.  Over the years just about everyone I talk to about this also uses the analog in.  There must be something very synergistic with this unit where the ADC and the DAC are able to work seamlessly together, but when that internal chain is broken by going digital in that synergistic magic is not allowed to happen.  Roger Sanders of Sanders Sound uses a stock DCX for the active crossover in his highly reviewed and highly resolving electrostats.  He uses them analog in and never considered modifying them.  He told me that was a good way to screw them up.

Brian wrote up a good tutorial on how to install the DCX:
 
http://www.audiocircle.com/index.php?PHPSESSID=8lt07tak95uq2k0ue69j05mae4&topic=63025.0 

This was written early on during what I would still call the discovery phase of all this unit was capable of doing.  In this tutorial he mentions using the set up of LH LH LH for the six output channels.  I don't do this.  My unit is set for LL MM HH which is a full three way design.  All this designates is that there are three stereo pairs being output from the DCX.  With the DCX you can make any pair anything you want and don't need to be concerned with the letter designations of low, midrange and high.  Since my unit is modified allowing full analog volume control of two of those three pairs (LL and HH only), I am using LL for the output to my V60 mid bass and HH for the mids and highs.  MM for me is the sub bass output to the VLAs.  My sub bass amps have volume controls of their own.

Here is a basic block drawing of how both the digital DCX and outboard analog crossovers are being used in my system.  Many ask if they can triamp a three-way speaker that does not use a separate subwoofer directly with the DCX, bypassing either an outboard analog crossover or a filter of some sort on the tweeter?  Technically I see no reason why not, but I know that Brian did not recommend doing that and instead recommended using the DCX as a two-way xover in that circumstance.  I know of several people that ended up blowing their tweeters even though they were being careful while triamping.  It may be that the DCX is not a good buffer for amp start-up for such a sensative component?



Tyson

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Re: D-OXO and the Digilog Adapter for SDE Speakers
« Reply #3 on: 12 Mar 2013, 12:57 am »
The miniDSP 2x8 is a good alternative to the DCX, and IMO sounds better, plus has the ability to do 4 way crossovers if/when you want to integrate subs to the usual 3 way VMPS speakers.  I like the interface better too, but any time anyone goes active, it's going to be a pretty steep learning curve.  It's worth it though, I heard a fully active VMPS RM40 setup yesterday in a dedicated audio room and it is one of the best sounding systems I've ever heard.