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Can an in-room measurement predict what sound is direct vs reflected?

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spacevector

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Wouldn't the difference would also include the speaker and microphone locations in the room?
Yes indeed. I guess better way to put it is "The difference is the combination of the room and the particular speaker/mic placement in the room".
I guess I'm not sure what you really seek.
That makes two of us.

I am going to attempt a measurement later and post here. I am not sure how to get the voltage right though. I think I can just throw a DMM on the speaker terminals and adjust level of signal in REW till I get it to read 2.83Vrms (sine wave 1kHz). Then do the sine sweep at that level.
 

aarons915

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So if anechoic data is already available - like from speaker reviews here, then all I need to do is take in-room measurement, scale it so that its at similar distance and voltage level like @andreasmaaan outlined and subtract one from other. The difference is room.

Kind of, the Klippel measurements are very powerful if you have PEQ, as you've seen in most speaker review threads people post various PEQ filters to flatten the listening window response while making sure it doesn't negatively affect the early reflections curve. That works better than any method I've found above the transition frequency. Below the transition frequency is room dependent so you'll need your own in-room measurements to sort that out. You can use PEQ to fix that as well but it's kind of a pain, if you have a good room correction software like XT32 or Dirac live a good option would be to limit the correction to 200-300Hz or so depending on where the room really takes over and then throw a few PEQ filters above that if your speakers benefit from it.
 
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spacevector

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I do use some EQ - I wasnt usually satisfied with results but seem to have had some decent luck lately. Yesterday I used the moving mic technique with RTA averaging. Here is some results. The red trace is no EQ, green trace is with EQ generated using REW.

The EQ filters REW spit out are below. I added a 120Hz shelf boost with 3dB to tune bass to liking (this bit seems never ending pursuit).

Filter 1: ON PK Fc 35.0 Hz Gain -12.1 dB Q 2.000
Filter 2: ON PK Fc 51.3 Hz Gain -5.3 dB Q 6.658
Filter 3: ON PK Fc 70.7 Hz Gain 9.0 dB Q 2.000
Filter 4: ON PK Fc 92.6 Hz Gain -8.0 dB Q 4.460
Filter 5: ON PK Fc 109 Hz Gain 3.4 dB Q 10.213
Filter 6: ON PK Fc 130 Hz Gain -7.0 dB Q 3.628
Filter 7: ON PK Fc 192 Hz Gain -7.9 dB Q 3.509
Filter 8: ON PK Fc 280 Hz Gain 9.0 dB Q 2.951
Filter 9: ON PK Fc 421 Hz Gain -5.9 dB Q 3.249
Filter 10: ON PK Fc 437 Hz Gain 5.4 dB Q 4.687
Filter 11: ON PK Fc 1280 Hz Gain 2.2 dB Q 1.956
Filter 12: ON PK Fc 1537 Hz Gain 2.4 dB Q 1.000
Filter 13: ON PK Fc 2496 Hz Gain -1.1 dB Q 1.063
Filter 14: ON None
Filter 15: ON None
Filter 16: ON None
Filter 17: ON None
Filter 18: ON None
Filter 19: ON None
Filter 20: ON None


Eq-RTA.png


Finally this is a measurement at LP of left speaker. I set receiver to -8dB and REW to -10.8dB to get the DMM to read 2.86V at 1kHz.
I must say, this setting was frigging loud. I never listen this loud, the room was shaking during bass portion of the sweep.

Left-speaker-noEQ.png
 

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aarons915

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I do use some EQ - I wasnt usually satisfied with results but seem to have had some decent luck lately. Yesterday I used the moving mic technique with RTA averaging. Here is some results. The red trace is no EQ, green trace is with EQ generated using REW.

No need to go that loud, around 75-80 db is more than enough for room measurements. If your speakers are the Studio 530 the only EQ I would do above the transition frequency is to take care of that 1500Hz resonance, the rest looks good. Then just EQ the bass to your liking under 200Hz or so and they should sound really good.
 
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