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Author Topic: Thinking outside the greybox  (Read 15023 times)

Langston Holland

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Re: Notched Crossovers
« Reply #20 on: March 20, 2012, 10:56:09 pm »

Turns out that Hayden was crazy enough to provide some very nice pink noise measurements of the MW12.

He followed the basic steps I outlined here and sent me the files to look at. Since he's looking to save some money on processing the MW12's, I also experimented with the most powerful $500 processor in the world (it was used) to develop an 8 channel flat phase present for the MW12. I don't have that much experience with install processors, but they have some features that are stunning as long as you don't run out of resources. I did have to reduce the number of parametric EQ and All Pass filters from the ideal due to the 8 channels I was after.

Hayden made the measurements in a large performing arts hall with excellent diffusion and the impulse responses were nearly as clean as an outdoor measurement. S/N wasn't amazing, but it's more than adequate for our needs. All measurements were on-axis with the mic at ear position with the wedge on the stage floor.

The raw low and high passbands of the MW12:



EAW's beautiful processing through the UX8800 "blue" preset for the MW12:



EAW's "hurry up and let's go to lunch" Lake processing "blue" preset for the MW12:



The raw full range MW12 output (purple) and X-Frame 88 processed full range output (cyan):



The phase dip at 1.5kHz is likely inaudible, but regardless I couldn't deal with it because I completely used up the four CPU's in the processor. I don't have access to a MW12 yet, though I have one coming within a week to demo. I'm looking forward to hearing the difference between the obviously superior UX biamped setup and the X-Frame 88 full range setup.

X-Frame 88 Preset schematic:

« Last Edit: July 19, 2012, 02:55:03 am by Langston Holland »
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God bless you and your precious family - Langston

Hayden J. Nebus

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Re: Notched Crossovers
« Reply #21 on: March 21, 2012, 07:48:54 am »

That's right, I'm crazy. Pay no attention to the man with the 80 all pass filters(at 500 bucks, that's $6.25 per filter!)

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Peter Morris

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Re: Notched Crossovers
« Reply #22 on: March 27, 2012, 05:20:54 am »


EAW does not include the emofilter in their Lake presets for the MW12. I'm sure this isn't an oversight. More on this in a bit.

Even though I've mentioned it a couple of times, I'm not sure some folks understand what I'm saying about out of band EQ, notches, etc. They are VERY useful on many occasions, but not when they are so far out of band that no part of their transfer function contributes anything to the loudspeaker's output. I'll quit now. :)

[

I think this is the first time, but Im not going to agree with you on this one  :-\ . Out of band filters even if they dont contribute to the measured output in term of SPL or phase can still have an audible effect even if they are applied when they 30 or 40dB down and out of band.
If there is a resonance in the driver somewhere it will produce a corresponding spike in the output, it will ring.  If its out of band you may not see it on the SPL or phase plot but you will see it in a TEF waterfall, and you will hear it.  The sound will be slight less clear.  Dealing with these types issues is one of the things that Gunness Focusing did.  There is of course a point where dealing with these issues becomes irrelevant.  In this case (assuming EAW is using a very similar driver to the 18sound 12CX800) its probably just worthwhile.

As a guess the notch / spike @2K5 was probably to do with a resonance in the VC.

Best Regards
Peter
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Langston Holland

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Re: Notched Crossovers
« Reply #23 on: March 27, 2012, 10:02:34 am »

Peter!

If this is the first time - you haven't been paying attention! I just added another question to my notepad the next time I see Dr's Gunness, Danley, etc.

I'm just a student with a keyboard.

One of the plates I started spinning yesterday is the MW12. It is an 18 Sound driver and very fancy. Certainly don't see it on their web site. :)

« Last Edit: July 19, 2012, 02:53:28 am by Langston Holland »
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Hayden J. Nebus

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Re: Notched Crossovers
« Reply #24 on: March 27, 2012, 10:55:46 am »

Peter!

If this is the first time - you haven't been paying attention! I just added another question to my notepad the next time I see Dr's Gunness, Danley, etc.

I'm just a student with a keyboard.

One of the plates I started spinning yesterday is the MW12. It is an 18 Sound driver and very fancy. Certainly don't see it on their web site. :)



This heer horse aint dead yet! grab yeer bats!
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Peter Morris

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Re: Notched Crossovers
« Reply #25 on: March 27, 2012, 07:15:49 pm »

Peter!

If this is the first time - you haven't been paying attention! I just added another question to my notepad the next time I see Dr's Gunness, Danley, etc.

I'm just a student with a keyboard.

One of the plates I started spinning yesterday is the MW12. It is an 18 Sound driver and very fancy. Certainly don't see it on their web site. :)



Nope I find I always agree with your comments  ;D, and you always make a great contribution     In this case I still needed to qualify my statement with the undecided  :-\ emoticon.

Just to add a little more in some cases the spike can be as large as 10dB, soooo if its electrically 30db down after the crossover its only 20 acoustically, and has to be dealt with, if its only a couple of dB it a different story.

The EAW / 18sound driver looks like a EAWs neo version of the 12CX800,:  something built around a 12ND9300 frame with ND1460 HF driver on the back.

Peter

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Riley Casey

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Re: Notched Crossovers
« Reply #26 on: April 03, 2012, 12:12:06 pm »

I need to visit this sub forum more often.  Might fine thread you have going here Langston. This is where the forum needs a thumbs up icon.

ProSoundWeb Community

Re: Notched Crossovers
« Reply #26 on: April 03, 2012, 12:12:06 pm »


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