How effective would heavy ceiling treatment work here?

[Descartes]

Ever tried heavy velvet curtains in front of these windows for listening at night!

 

[ozzy9832001]

I've never tried just treating the ceiling and not any other surfaces. I feel it would cause more problems than it would solve, since the absorption would be very uneven. I maybe wrong. Over the summer, I'm going to redo my office and I'll be interested in posting the results for the panels as I put each surface in.

 

[audiofooled]

Sure... some of the other steps below is just to improve readability of the measurements:

1) Apply some smoothing to make the magnitude and phase readable
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2) If the phases aren't aligned, apply 'cross corr align' before vector averaging the left and right measurements -- I just don't want to look at each channel individually for the sake of expediency!
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3) If the phase and IR timing still looks off, apply 'estimate IR delay' and/or 'invert polarity'
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4) Let REW calculate or create a 'minimum phase version' copy of the LR vector averaged measurement
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5) Apply frequency dependent windowing (the 'IR Windows' button right beside 'SPL meter') to both original and MP version copy
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Dips or reduction in level occurs when delayed pressure/energy outside the specified window is removed -- usually caused by reflections. The MP version is what the transfer function would be if the (peak) "energy" along the time domain axis were theoretically pulled in or compressed much closer t=0 i.e. as if the measurement were converted to its minimum phase equivalent and excess phase were removed. The larger the dip, the greater the delay in that frequency range and/or 'smearing' of sound across time.

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*In general, when using FDW for EQ purposes -- in order to avoid over-correcting or under-correcting -- more cycles (e.g. 15) should be applied to the lower half of the response while fewer cycles should be used when approaching the highest frequencies.

**Oh, yeah, you're supposed to avoid filling-in such dips as that will only increase/worsen the problematic non-minimum phase or the reflected-delayed energy!

Yes, great job!

I would agree that 8c are slightly better performers, however, IMO the OP is getting far too little direct sound either way, even though both are objectively very good loudspeakers.

If different positioning/setup of loudspeakers and MLP is not and option, then acoustic treatment or very different loudspeakers would help tilt the scale of the direct/reverberant field. Essentially, what @Bjorn already suggested. Narrower and broadband constant directivity.

To illustrate, I'd focus on the region of 700-7kHz, where clarity is most critical and early reflections would be most detrimental. In any room there would be a critical distance where sum of all of the reflections, reverberation and room modes would be greater than the direct sound.

Spectrogram of the before mentioned region, from your vector average of 8c's:

This is my system, but at 0.5 meter distance, and about 0.7m bellow tweeter level, where there's obviously no direct sound, so everything is off the chart:

But at my MLP which is 3,5m away it looks like this:

Finally, my headphones point blank:

 

[tifune]

Narrower and broadband constant directivity.

I'm certainly open to this, but I'm not sure what speakers meet that criteria?

Sure... some of the other steps below is just to improve readability of the measurements

Thanks so much for this; REW is a bit overwhelming given my time constraints.

 

[flysouth]

had similar ceilings. buddy of mine said clouds were great

 

[audiofooled]

I'm certainly open to this, but I'm not sure what speakers meet that criteria?

Speakers with constant directivity, either waveguides or horns, or perhaps even synergy horns. Erin explains this on JBL M2 measurements, which has such radiation pattern 800-8kHz:

 

[tifune]

Speakers with constant directivity, either waveguides or horns, or perhaps even synergy horns. Erin explains this on JBL M2 measurements, which has such radiation pattern 800-8kHz:

TY, that part I do think I understand; I'm not sure what speakers offer significantly narrower dispersion? Line arrays?

 

[audiofooled]

TY, that part I do think I understand; I'm not sure what speakers offer significantly narrower dispersion? Line arrays?

IMO the dispersion doesn't have to be specifically narrow, if the loudspeaker has flat DI but also flat FR at a degree off axis to which you toe them in. The benefit is that you balance how much energy you actually give to side wall reflections by missing and not hitting them like in wide dispersion. Granted this is not trivial to do when it comes to the design. To understand the complexity of it, but also benefits, I'd recommend this video by Earl Geddes:

 

[Justdafactsmaam]

TY, that part I do think I understand; I'm not sure what speakers offer significantly narrower dispersion? Line arrays?

Planars