Cinema Screen Array JBL 3731 and McIntosh

[Rick58]

Yes, in looking at the S'phile and other graphs, the ~1ms decay is certainly in anechoic conditions! and related to the speaker itself; I realized that later. Another room CSD plot I saw somewhere was on the ~300ms time scale. So I now understand that this is the proper way to look at room treatment results.

I don't think I can get away with room treatments ... at least to the extent they would make a real difference. Looks to me like some DSP based multi-filtered correction units can achieve pretty good results WRT the CSD plots (I am not certain what RT30 really means? but if it's the room reverberation time to -30dB SPL, seems related to the CSD plot).

I have read (learned opinions? or otherwise, I don't know) that it is best to treat the room, then apply DSP processing for best results. In the absence of treatment, seems to me that DSP is better than nothing! I hope to find out some day, hopefully in a broadband manner, not 'just' in a subwoofer unit.

For low budgets, looks like something like a DSPeaker Anti-Mode 8033 would be a good start, but IIUC this only can be applied on the subwoofer signal. I have resonances at (25), 50, 100, and 200Hz, and my monitors roll off at ~63Hz ... so I think I would certainly need treatment for the 100 and 200Hz resonances.

Looks like the processing (applying phase correction, not only EQ) can actually work rather well in optimizing the CSD.

I hope someday to be able to try the McIntosh/Lyngdorf unit ... but for the short term, something like the 8033 (and I know there's a 'cheap' version of the Lyngdorf for 'semi-professional' use ... ah, yes, the KRK Ergo) will have to do! but 'going cheap' will, I am afraid, compromise some of the good sonic things that I am working hard to achieve.

[Rick58]

Well ... seems like that might just be a (near-term, until I can afford a major upgrade) solution!
http://audioaficionado.org/isolation...ect-500-a.html

[Still-One]

Originally Posted by Rick58

Well ... seems like that might just be a (near-term, until I can afford a major upgrade) solution!
http://audioaficionado.org/isolation...ect-500-a.html

I wouldn't call this Room Correction when it only handles frequencies up to 500hZ. That is limited bass correction. Now it is quite possible that in many rooms this may be al you need and as you note the price is not too high to give it a try.

[Rick58]

Yes - I understand it only works up to 500Hz, but that seems adequate for my overall bass issues. I listen in the nearfield (to monitors) so >500Hz, things should be pretty OK (sound from monitors only, and well away from walls ...).

By the time I can afford a MEN whatever, I hope to also be able to afford some nice larger full-range speakers ... this may be part of a retirement present to myself in about 10-15 years!

[jwc]

Nice JBL cinema setup. I always wanted to hear those.

I'm curious about the M/T passive crossover. Those speakers are for "behind the screen". I have some klipsch ones like that too. Thing is....all the passives available are EQ'ed according to THX specs behind the screen. There will be a rolloff of the highend and a prominence in the mids. W/o the screen.....the system sounded "shouty" in the mids.

I therefore had to go all active. Then EQ the "CD Horn" part myself with active EQ.

jc

[Mctwins]

Hi, jwc

I don't have this problem, the sound is very good. It dosen't bothers me at all if I don't have any screen in front of the speakers. I will add a DBX Drivepack PA+ in my system soon. Maybe it will be better.
Thanks

[jwc]

That is great to know. Glad you are liking the big horns......me like them too....wish i could hear yours....

I've had the dbx PA.....nice unit. no noise...clean. Lots of features...

Right now I have an Ashly XR-2001 on my big horns. love it. I also have the XR-1001 on another system an love it too.....it is the two way version.

I've had the EV Dx38. It is a digital unit...I liked it a little better than the dbx PA.

I would love to hear the DBX 4800....

Rock on big horn lover....

jc

[Mctwins]

Hi
jwc.....Glad you like it, look at this.
Now I have change from DBX 223XL to Driverack PA+ and done some adjustment. As you can see the freq response has improved since the last time. I have not done any other changes such as room treatment or different speakers position, everthing is the same as before.

The difference in the bass region is due to the cutoff freq at 40 Hz Butterworth12 slope. A guy from the DBX forum advice me too do this, he said I could damage the cone. I can't explain why but I am testing it for now, will come back with some more info on that.
The reverb time T30 and CSD is the same, nothing has change here.

The green is DBX PA+ and the yellow is before.
Thanks

[jwc]

That is a great looking curve.

Putting that 40Hz cutoff in there I would bet would make the bass for music more "snappy".....something I like. Throw in a movie.....well....

If you are sitting within 15 feet of those beasts, I can't imagine you would blow the cone.

jc

[Mctwins]

Hi
I have installed some new diffusion in the ceiling and those I had on the ceiling I put them on the side walls. Also change the gear position. You can see the new DBX PA+ unit as well.
Thanks