timbley Posted April 29, 2004 Share Posted April 29, 2004 Has any one ever tried one of these crossovers? It looks intriguing. I wonder if receivers will be available in the near future with crossover functionality built right in and kept entirely in the digital domain right out to the amps. Quote Link to comment Share on other sites More sharing options...
timbley Posted March 26, 2005 Author Share Posted March 26, 2005 ---------------- On 4/29/2004 3:20:11 PM timbley wrote: Has any one ever tried one of these crossovers? It looks intriguing. I wonder if receivers will be available in the near future with crossover functionality built right in and kept entirely in the digital domain right out to the amps. ---------------- To answer my own post: Yes, I've tried one with my RF-7s. After everything I've read about active crossovers, curiosity got the best of me and I ordered one. I just got the crossover this week. It works very, very well in conjunction with the DEQ2496 and measuring microphone, which I found indispensible to getting the speakers EQ'd correctly. I had some deep concerns about the DCX. My biggest worry was sound degradation due to the extra d/a a/d step required between the DCX and my Panasonic SA-XR50. I had a real fixation on keeping the path pure digital. I was also worried about converting the balanced outputs to single ended, and having to attenuate the signal digitally before feeding it to the Panny, loosing precious, precious bit depth. Well, I can say now that all my worries seem very, very silly. This is a HUGE upgrade! I'm using 48db/octave slopes, with the crossover point set at 1.82kHz. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted March 27, 2005 Share Posted March 27, 2005 how do you bi or triamp an rf-7? tony Quote Link to comment Share on other sites More sharing options...
greg928gts Posted March 27, 2005 Share Posted March 27, 2005 Can you explain to the digitally-challenged how you're keeping the signal pure digital out to the amps? I have a DAC in my system which changes the digital signal to analogue before the preamp. That's about the extent of my knowledge when it comes to digital. Oh no, I feel another experiment coming on, I wonder how much this one's going to cost me. Greg Quote Link to comment Share on other sites More sharing options...
timbley Posted March 27, 2005 Author Share Posted March 27, 2005 ---------------- On 3/27/2005 9:03:04 AM sunnysal wrote: how do you bi or triamp an rf-7? tony ---------------- I'm bi-amping using my Panasonic receiver's surround channels to run the tweeters and it's front left and right channels to run the mid-woofers. I bypassed the internal crossovers. Quote Link to comment Share on other sites More sharing options...
timbley Posted March 27, 2005 Author Share Posted March 27, 2005 ---------------- On 3/27/2005 9:03:15 AM greg928s4 wrote: Can you explain to the digitally-challenged how you're keeping the signal pure digital out to the amps? Greg ---------------- Greg, the pure digital path I was using involves using digital output from my Denon DVD player straight into the Panasonic receiver, which performs pre-amp functions in the digital domain, and then sends the modified digital signal to a PWM amplifier, which in effect acts as a high power D/A converter that can feed the speakers directly. Now that I'm using the DCX crossover, I have to use it's analog outputs into the Panasonic's analog 5.1 surround inputs. This means that the sound signal is going through D/A converters on the DCX, and then going back through A/D converters in the Panasonic. This surely has some degrading effect on the sound, but not nearly as much as the caps and coils in my speakers did. Quote Link to comment Share on other sites More sharing options...
greg928gts Posted March 27, 2005 Share Posted March 27, 2005 I assume the model you are using is Behringer DCX2496 Ultra-Drive Pro Digital Crossover System? It says that there are 3 analogue inputs, but it doesn't mention digital inputs. Would I be able to go from my Denon CD transport via its digital output into the DCX? Did you say something about converting the output jacks from 3-pin XLR to something else? Is this unit remote control operable and if so, how? Please remember that I'm a digital dummy. Greg Quote Link to comment Share on other sites More sharing options...
timbley Posted March 27, 2005 Author Share Posted March 27, 2005 Greg, Yes, the DCX2496 is the crossover. It has three analog inputs, A,B,and C. "A" can be set for use as a digital input on the setup screen. You can hear a switch click when you select digital input. The input is balanced XLR, so you need to adapt the digital output of your CD player if it doesn't have XLR. I get around this by using the DEQ2496, which has optical digital input and XLR digital output. I think it's necessary to also get the DEQ and it's calibrated microphone to help equalize the speakers. The DCX has parametric EQ functions, but unless you've got a golden ear, it can be pretty difficult to correctly EQ untamed drivers without the mic. and real time analyzer to give you guidance. I can hear when something's wrong with the EQ, but I can't guess very well how to fix it. I also find the 31 band graphic EQ on the DEQ easier to use than than the parametric EQs. On the output, the DCX has 6 XLR analog balanced outputs, allowing for up to 3 way crossovers on a stereo pair. I bought some inexpensive Hosa cables that convert the XLR to RCA for input into the Panasonic receiver. The output gain from the DCX is a little too high, so I digitally attenuate the signal by 6 db using the DCX, and set the Panasonic to "A/D attenuate." This keeps the overflow warning from blinking on the Panasonic. No remote control functions are available as far as I know. Quote Link to comment Share on other sites More sharing options...
greg928gts Posted March 27, 2005 Share Posted March 27, 2005 So, you're using two pieces, an EQ and a Crossover, both digital. I wonder what the extra componentry and wiring does to the signal quality as it comes from the transport to the amps. I'm used to a very pure signal path in my own system. These components are cheap enough to try though. They mention something about remote control on their website, but it may be through a computer link. I'm thinking that some company may make a remote that will work with this unit through that plug in the back. I would love to have real time remote control of the EQ, level of outputs, and overall system volume. Would you know how the D/A converters in the DCX compare to my MSB Link DAC III with Full Nelson upgrade? Greg Quote Link to comment Share on other sites More sharing options...
timbley Posted March 27, 2005 Author Share Posted March 27, 2005 ---------------- On 3/27/2005 10:23:01 PM greg928s4 wrote: Would you know how the D/A converters in the DCX compare to my MSB Link DAC III with Full Nelson upgrade? Greg ---------------- From everything I've read, I'd say the D/A's on the DCX would be a downgrade from your DAC. That's the hell of it. You step down in one area, but you step way up in another. Quote Link to comment Share on other sites More sharing options...
greg928gts Posted March 28, 2005 Share Posted March 28, 2005 What about running out of the DCX and into the MSB? Is there a separate EQ for each of the 6 outputs on the DCX? Greg Quote Link to comment Share on other sites More sharing options...
timbley Posted March 29, 2005 Author Share Posted March 29, 2005 Yes, there's a seperate Parametric EQ on each output. You can output the DCX into anything that takes analog inputs. Sorry, I can't remember what the MSB is. Ooh, tonight I tried something. I made a little compromise and put a 10 ohm resistor in series with each tweeter. This just happened to make the tweeters output match the woofers almost perfectly at the crossover point. So, I listened for a while without any EQ at all, just the 48db/oct butterworth crossovers set at 1.82kHz. This is the best I've heard so far! It really doesn't need any EQ at all. It's super clear. Vocals are really nice and present. I don't think I need the DEQ any more! Quote Link to comment Share on other sites More sharing options...
Griffinator Posted March 29, 2005 Share Posted March 29, 2005 Dude, you're putting so much cheap Behringer crap into your signal chain, I'm frankly amazed that you haven't completely destroyed the signal before it ever makes it to the speakers... Behringer "pro" gear is absolutely awful, compared to the companies it rips off on a regular basis. The crossover of which you speak was lifted from PreSonus' designs - not that great a company to begin with. When you step out and invest in some serious DAC and DSP devices (by Benchmark, Waves, et al) you'll be shocked at how utterly superior the sound quality gets all of a sudden... Quote Link to comment Share on other sites More sharing options...
timbley Posted March 29, 2005 Author Share Posted March 29, 2005 Hey, all I can say is the Behringer gear is doing a nice job in my system, and it's inexpensive. The DCX certainly sounds better than my passive crossovers did. The DEQ made my speakers sound better when running my passive crossovers than when I bypassed it, night and day in my opinion. It may be a cheap knock off of something, but it does a decent job. Now that I'm biamping, I'm finding I don't need to EQ. I like the way the speaker sound "raw," although I have added 10ohm resistors in series with the tweeters to bring them in line with the woofers. Edit: While highly listenable without EQ, I still like some EQ after all. I may step out for more expensive gear some day. DEQX looks intriguing. Behringer is what I can afford right now. It's made it clear to me that I definitely want to continue to use active crossovers. Quote Link to comment Share on other sites More sharing options...
timbley Posted April 24, 2005 Author Share Posted April 24, 2005 It's been about a month now that I've been using my Behringer DCX active crossover. I've switched to using JVC-F10 receivers, two of them, to tri-amp the RF-7s. I heard immediate improvements in clarity and bass response by giving each 10" midwoofer on the RF-7 it's own amp channel. I've tried crossover frequencies ranging from 1.6kHz to 2.2kHz. At first I liked the lower crossover frequencies because the horn tweeter had a little extra snap to it. But with the 10" drivers each on their own amp now, I don't hear them giving up anything to the horn in the way of speed and clarity, so I've settled on 2.2kHz. Also, the dispersion seems better on the dual 10" drivers. Letting the horn go too low deadens room ambience in a way I don't like as much. I also tried doing a 2.5 way configuration, where the top 10" driver carries the midrange signal near the tweeter crossover by itself, and is joined by the other 10" woofer, which is crossed over lower to cover the bass. This sounded very similar to me to lowering the crossover frequency of the tweeter. It effectly reduces the cone area of the midrange sound. It sounds slighlty more accurate perhaps, but once again I didn't like it as much as when letting the two 10" drivers together carry as much of the midrange as possible. It's juicier, and it livens my listening room up more. I experimented with using a 10 ohm resistor in series with each tweeter, thinking it'd be better than applying digital attenuation. I get the impression that the resistor adds a slight glaze to the tweeter, so I removed it. I'm not hearing any problems with the digital attenuation, despite comments by some other DCX users. 48 db/octave slopes are my favorite. Shallower slopes work, but give up something in the way of clarity and imaging. Is this all worth doing? I can't say. I think I could spend the rest of my life playing with the EQ, never being sure of what I like best. The funny thing I've noticed about all audio upgrades I've ever done is that I appreciate them less and less as time goes by. I had a great time as a youngster listening to an AM/FM shortwave radio that had one "huge" 5 1/2" driver and a little tweeter. I was transfixed by music I heard out of that thing. So I upgrade, but eventually I don't end up enjoying music any more tham I used to, because I was already enjoying it completely. Quote Link to comment Share on other sites More sharing options...
dragonfyr Posted April 24, 2005 Share Posted April 24, 2005 I would be curious to hear this, but I too fear that you are simply overprocessing the signal! And with each successive gain stage you are increasing the noise floor as well. And, I am curious if you are taking advantage of the opportunity to align the acoustic centers of the drivers in the time domain with an appropriate delay offset... And using the second zone stage to feed bi amp? Did I read this right? Wow, with so much variance and additional processing of the signal in so many ways.....I would LOVE (maybe the proper phrase should be "would be terrified"!) to see the transfer function of this total process! I fear that this is akin to going to a health food store to buy whole foods and walking out with just another insanely overprocessed protein powder...albeit with a bit price and a fancy label... Quote Link to comment Share on other sites More sharing options...
timbley Posted April 24, 2005 Author Share Posted April 24, 2005 ---------------- On 4/24/2005 5:37:42 PM dragonfyr wrote: I would be curious to hear this, but I too fear that you are simply overprocessing the signal! And with each successive gain stage you are increasing the noise floor as well. And, I am curious if you are taking advantage of the opportunity to align the acoustic centers of the drivers in the time domain with an appropriate delay offset... And using the second zone stage to feed bi amp? Did I read this right? Wow, with so much variance and additional processing of the signal in so many ways.....I would LOVE (maybe the proper phrase should be "would be terrified"!) to see the transfer function of this total process! I fear that this is akin to going to a health food store to buy whole foods and walking out with just another insanely overprocessed protein powder...albeit with a bit price and a fancy label... ---------------- Curiosity is what got me into this in the first place. I would like to have someone else with audiophile ears to listen to my system and see what they think. Maybe they'd hear some obvious shortcoming I'm not. This system certainly does some high powered processing to the digital signal. I guess you could consider a digital EQ, or a digital crossover a gain stage. Neither introduce much of a noise floor. As for the digital EQ, I can't hear anything from that. The D/A converter on the crossover must add something, but most everybody has to have a D/A converter at some point, at least for their digital sources. I've only got one in the signal chain. The amplifier itself has the most audible noise floor, as can be verified by unhooking all the inputs and just turning up the volume and listening. There's really an extremely low noise floor in this system, so I rule that out as being any kind of a problem. I first started experimenting with digital processing using the DEQ equalizer. At that time, I was using it's digital input and output to a Panasonic SA-XR50, so there wasn't really any D/A converter at all. The noise floor was as close to absolute zero as I can imagine. It was easy for me to test the effect of the DEQ by bypassing it. After listening with and without the DEQ, it was obvious to me that it improved the sound in many more ways than it degraded it. It didn't seem to be degrading it at all, actually. I don't feel the DCX crossover is adding any audible degradation either, at least not from it's digital processing, although the D/A converter stage may not be as good as some. A simple resistor in parallel with the tweeter had a more damaging effect to my ears than applying some digital EQ and attenuation to the tweeter circuit. Quote Link to comment Share on other sites More sharing options...
timbley Posted April 24, 2005 Author Share Posted April 24, 2005 ---------------- On 4/24/2005 5:37:42 PM dragonfyr wrote: And, I am curious if you are taking advantage of the opportunity to align the acoustic centers of the drivers in the time domain with an appropriate delay offset... ---------------- I forgot to answer this on the last post. I've played around with applying delay to the drivers. I applied a little to the 10" midwoofers on the assumption that the horn driver is a little further back because of the horn length. I didn't notice any improvement. I don't have a way of testing the delay, so I was shooting in the dark just to see if I noticed anything. Quote Link to comment Share on other sites More sharing options...
ben. Posted April 24, 2005 Share Posted April 24, 2005 From what I understand, the RF-7 crossovers have plenty of EQ going on , so it would make sense that when using an electronic crossover, EQ would sound better than forgoing it. Quote Link to comment Share on other sites More sharing options...
timbley Posted April 24, 2005 Author Share Posted April 24, 2005 Yes, there's a filter in the tweeter circuit to bring it down to match the woofers, and flatten it's response. I was suprised at how far from flat the tweeter's response is, especially as it drops off very sharply long before 20k. It almost looks like a supertweeter on top could be useful. I see other tweeter response graphs that looks a lot flatter. I know very little about horn design, and practical limits of frequency response. For whatever reason, Klipsch decided that it was better to apply a filter in the crossover than to try to design a horn/driver that could give nearly flat response from 2.2 to 20k. Maybe that's just not possible. Quote Link to comment Share on other sites More sharing options...
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