Room correction, speaker correction anything above Schroeder a mistake?

[Jimbob54]

From what I'm reading people are saying it may be pointless to EQ speakers above a room's schroeder frequency? I currently cut of auto EQ at 500Hz in my room (EQ'ing only below 500Hz). Should I instead try to estimate the schroeder frequency for my room and place the cut off at that frequency instead? And why?

Thanks.

Pretty sure there is an existing thread with almost exactly this title. Suggest browsing for it.

 

[luft262]

Pretty sure there is an existing thread with almost exactly this title. Suggest browsing for it.

After looking harder I found this.

Room correction, speaker correction anything above Schroeder a mistake?

Discuss. The Schroeder frequency is the boundary between reverberant sound and a region dominated by widely space room modes. Obviously not a fine exact line. Below the Schroeder frequency the room responds with areas of resonance and nulling which will depend upon the location of the source...

www.audiosciencereview.com

I'll ready though it.

 

[luft262]

One key issue is how the measurements are made. The resolution of our hearing progressively gets lower and lower as frequencies go up so the frequency response needs to be measured that way. Without it, you will be fixing troughs and peaks that are not audible.

The other point is that the speaker dominates the response in higher frequencies. So poor response there is best fixed using a better speaker.

Since our hearing gets poorer as the frequency increases would you recommend changing a REW frequency graph reading to variable so that the peaks and troughs become more of a psychoacoustic estimation in the highest frequencies?

 

[ernestcarl]

I think the more apt descriptor is that it's "tricky" to EQ above Schroeder -- not counting the more common broad type HF shelving filters nearly all studio professional monitors have built-in.

 

[syn08]

At the first glance, I read "Schroedinger frequency" and I could not stop a shiver .

 

[AdamG]

Pretty sure there is an existing thread with almost exactly this title. Suggest browsing for it.

Thank you @Jimbob54 for pointing out the duplicate thread. Threads consolidated.

 

[chych7]

EQing above Schroder is useful to get L/R speakers to match better, in the presence of room interactions. This directly impacts imaging performance; the better the speakers are matched to one another, the more precise the imaging. This is quite obvious, IMO; if L/R is 100% identical and a tone is played, you get a perfectly centered image. If one channel is louder than the other evenly, the image shifts towards the louder speaker. However, if one channel is unevenly (across the freq range) louder/quieter than the other, then the image smears; some portions of the sound go towards one speaker, and others go to the opposing speaker. Room interactions/reflections can affect this behavior for the different speakers, and room correction could be used to reduce this effect.

As to meeting a particular target curve or correcting some phase response, I'm not quite as sold on that part, other than for some basic tone control/correction (i.e. tame a bright speaker).

Below is some analysis I had done when I was evaluating Audyssey XT32 and Dirac Live in my system. Both DRCs improve L/R matching vs. no correction for SPL. Each line is the average of 6 measurement points around the MLP.

Additionally I looked at L/R phase error, which is also something that is audible (i.e. flip the phase of one of your speakers, you'll hear a difference). DRC improves upon it, although I found Dirac doing something weird here and increasing the error in the mid range. Subjectively I did not like the way Dirac sounded above the Schroder frequency; the imaging got more precise but the soundstage sounded like it reduced. Audyssey, on the other hand, sounded better on than off above the Schroder frequency. The average error numbers are calculated on linear scale, but when viewed in log scale, it looks like Dirac is worse than No Correction.