Is the internal crossover not bypassed? Isn't that missing a large point of going active?
Is the internal crossover not bypassed? Isn't that missing a large point of going active?
The purpose of the exercise was to add delay and to arrive at true LR 24 filters, then evaluate the results. It was not to go full active and bi-amp either system. No one is advocating that anyone who owns an S3900 or S4700 run out and buy a dbx and a second amp. It just so happens that the exercise resulted in very positive changes. I have no idea where it all fits into the total equation, e.g. does two grand for a dbx and a second amp yield a greater bang for the buck than hooking up a single two thousand dollar amp?I've never looked at the dbx manual. If one has to use pre and post to get ten then yes, that is what he did. No different than the Crown HD and M2. I have posted how the Crown HD and M2 were configured and they do indeed use pre and post. It has been mentioned that the problem with the dbx and the lesser Crowns is that there are not enough PEQ points to properly implement an in-room fully active setup.
Buy two... go digital out on the first and digital in on the second, clocking them together?
(I'm just blowing smoke... can you even do that without cutting into their guts?)
Good question... I was thinking 4800/20 apparently, with digital I/O.
So any follow-up on this project?
What about the E2 ?
The 4430 for example would clearly deserve some DSP magic...
David Smith recently said something along those lines on the diyaudio forum, more specifically about the 2344 and how good it would become if properly EQed.
Found the post:
http://www.diyaudio.com/forums/multi...ml#post3599353
Originally Posted by speaker dave (David Smith)
"I haven’t gotten back into working with the DBX or with any other speaker models. I am using an AllDSP model PLP226 Signature. It is basically 2 in and 6 out which works for my Tri-amp system I am not using the UHF at all. I actually did my design with my speakers in place in my living room. I put in a 4 th order LR crossover target (750 Theoretical) and made 4 mic measurements of each of my woofers and HF units. Averaged the 4 positions for each transducer and used those 6 curves as the transducer measurements. I then applied the necessary crossover slopes and frequencies to get the acoustic measurement to match the electrical target as closely as possible. It doesn’t matter what electronic slope and frequency is used so long as the actual acoustic response is close.
Next I applied the necessary EQ to get the crossover slopes tuned in. Once done, I turned everything back on and made a Left (or Right) channel measurement using the same 4 mic positions averaged. The summing came out nearly perfect, as it should. I did the time delay by choosing one of the mic positions that gave the smoothest curve through crossover and inverting the polarity on the HF. I adjusted the delay for the deepest and most symmetrical notch at crossover. Flip the phase and all goes flat again. Finally, I applied some global EQ to the entire system to clean up any remaining room of summing issues. It is very simple to do, but it takes forever due to the multiple measurements and repetitive nature of things. My results were awesome.
The DBX Driveline 260 can do the job nicely although it is a little limited in PEQ filters. You have to be pretty efficient. I am currently looking at other High End solutions which incorporate built-in Preamp functions so I can ditch my analog preamp. Among the contenders are the Ground Sound DCN28 and the DEQX HDP-4. All are pretty pricey. The DBX is cheap at about $1000."
"I haven’t gotten back into working with the DBX or with any other speaker models. I am using an AllDSP model PLP226 Signature. It is basically 2 in and 6 out which works for my Tri-amp system I am not using the UHF at all. I actually did my design with my speakers in place in my living room. I put in a 4 th order LR crossover target (750 Theoretical) and made 4 mic measurements of each of my woofers and HF units. Averaged the 4 positions for each transducer and used those 6 curves as the transducer measurements. I then applied the necessary crossover slopes and frequencies to get the acoustic measurement to match the electrical target as closely as possible. It doesn’t matter what electronic slope and frequency is used so long as the actual acoustic response is close.
Next I applied the necessary EQ to get the crossover slopes tuned in. Once done, I turned everything back on and made a Left (or Right) channel measurement using the same 4 mic positions averaged. The summing came out nearly perfect, as it should. I did the time delay by choosing one of the mic positions that gave the smoothest curve through crossover and inverting the polarity on the HF. I adjusted the delay for the deepest and most symmetrical notch at crossover. Flip the phase and all goes flat again. Finally, I applied some global EQ to the entire system to clean up any remaining room of summing issues. It is very simple to do, but it takes forever due to the multiple measurements and repetitive nature of things. My results were awesome.
The DBX Driveline 260 can do the job nicely although it is a little limited in PEQ filters. You have to be pretty efficient. I am currently looking at other High End solutions which incorporate built-in Preamp functions so I can ditch my analog preamp. Among the contenders are the Ground Sound DCN28 and the DEQX HDP-4. All are pretty pricey. The DBX is cheap at about $1000."
Hi 4313B,
Have You any idea what are the mic positions : '...made 4 mic measurements of each of my woofers and HF units..."
Regards
ivica
Hi Ivica,
I am sure you still would prefer the answer from "the source", but I can recommend emulating the
locations where a pair of people's ears would likely be while listening ... roughly a 3ft wide window.
When setting up Titanium Dome's "250Ti" 4-way active system, -final- in-room measurement/adjustment
cycles were accomplished this way. This seemed to pass muster with the visiting audio giants that this
process was described to, followed by a bit of listening. Many other individual measurements were made,
but this last step helped to correlate listening experience to worthwhile adjustments. E.g., balancing in-situ
FR measurements between channels greatly enhanced imaging/sense of space.
I'd be happy to hear specific recommendations (and rationale) as well.
Sounds fun!
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
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