Full Room Treatment & Room Correction

boxerfan88

boxerfan88

Well-known member
Wise advice as seen elsewhere.

Getting the exact frequency is difficult but ultimately also not that important, because the transition from perceiving the combined room+loudspeaker response (at low frequencies) to hearing the loudspeaker direct sound and room sound as two separate phenomena (in higher frequencies) is gradual anyway.

This is also why I'd always recommend to use 'variable' smoothing when calculating EQ filters - it will give no smoothing at low frequencies (where you need to correct peaks) but do a lot of smoothing at high frequencies (which you should not touch, or possibly only with low-Q/wide filters). I also prefer to use MMM instead of sweep measurements as basis for EQ - IMHO MMM is quicker and directly gives results that are comparable to anechoic PIR (above approx. 1kHz).
Click to expand...

Regarding which peaks/dips to correct:
  • You should not correct any dips with EQ; ideally you should instead optimize loudspeaker and MLP placement to minimize them. Note that the dips are mainly caused by the distance of loudspeakers from nearby walls/ceiling/floor - i.e. SBIR.
  • Peaks should be brought down by PEQ, and I'd suggest to EQ all peaks under about 300Hz. You can probably get similarly good-sounding results by EQ-ing only the big peaks (as those are the most audibly offending) - e.g. in my destop system I use only 3-bands of PEQ and still get a good result - but if you have the option to run more bands of PEQ it's definitely worth to try.
  • Experiment a bit with target curves - namely try a (slight) downward slope and/or a small boost <200Hz instead of a fully flat curve. This is to account for the natural rising directivity (with frequency) of conventional front-firing loudspeakers.
Click to expand...


.
 
boxerfan88

boxerfan88

Well-known member
The ~85Hz dip from your in-room response suggests to me one of two most likely possibilities:
  1. The front faces of your monitors are ~1m away from the wall behind them. If so, I'd try to push the loudspeakers as close as possible to the wall behind - that would move the dip higher in frequency to where it can be more easily treated. If your monitors are back-ported leave at least ~5cm between the wall and the monitor for the port to function correctly.
  2. You are using a subwoofer which is close to being out-of-phase with the monitors around 85Hz. If so, I'd try reversing the phase switch on the sub and remeasuring.
Click to expand...

Why does the HiFi sellers like to do the opposite (ie. pull the speakers a few feet away from the backwall) ?

Wouldn't pulling the speakers a few feet from the backwall cause the cancellation dip to be right smack in the middle of the bass thump area?

0.6m => 143Hz **
1.0m => 87Hz
1.5m => 57Hz
2.0m => 43Hz
2.5m => 34Hz

Ref: http://tripp.com.au/sbir.htm
 
Last edited:
boxerfan88

boxerfan88

Well-known member
I came across this post out there. Very interesting bit of information. Same model yet sound different in different rooms.

Quote::
Every loudspeaker is unique, I work in a studio where we have the same GENELEC Monitors in each of our 22 rooms and they all sound different due to room sizes and furnishings.

If you like the sound and Aesthetics then that’s all that matters. Enjoy them and let your own ears decide.
Click to expand...
 
boxerfan88

boxerfan88

Well-known member
Interesting tid bits:
  • The precedence effect, where the brain discounts arrival of signals after the first, helps. The first arrivals also are the primary cue for binaural localization, with the uncorrelated late arrivals sensed as "envelopment."
  • The upshot is to smoothly equalize the direct arrivals at high frequencies, remove the worse peaks in the lows, and not touch deep low frequency dips.
  • Broad dips can be equalized.
  • Do not correct overall phase and magnitude with the processing or you will cause unpredictable pre-echo.
  • You need to equalize gain and delay from each speaker just for the first arrival, which locks in the spatial cues.
  • Correct the worst problems with the speakers or room, and leave other problems alone.


    Ref: http://www.aes-media.org/sections/pnw/pnwrecaps/2008/jj_jan08/
 
You must log in or register to reply here.
Top