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Assessing Room Correction Products: Dirac And Acourate

Examining the reality of tools designed to counter low frequency acoustic problems with equalization or processing.

By Ethan Winer January 10, 2019


I agree with proponents that EQ can help to reduce the level of boomy peaks.

I know several audio professionals whose ears I trust, and I can’t refute the improvement they claim. I heard it myself when testing the Audyssey system in a small square room, as described in the Audyssey Report linked earlier. But we can’t overlook the added ringing, or the listening seats where the response was made worse.

This is why I prefer bass traps over EQ, though I agree that EQ can help in square rooms that already have bass traps.

No matter what the vendors of “room correction” devices claim, it’s simply impossible to improve one problem without creating others. And it’s also impossible to reduce ringing by a meaningful amount, or to improve nulls without adding even more ringing.

This last graph (Figure 8) from my article Bass Trap Myths shows a bedroom size space with and without bass traps. As you can see, the response and ringing are both improved, at all locations in the room, and not one location was made worse.

Figure 8: This shows the improvement in response and ringing using only bass traps in a bedroom size space.

In home-size rooms low frequency peaks are generally 6 dB or less, but nulls are often 20-30 dB or even more. So nulls are usually the bigger problem — in a hi-fi listening room or home theater nulls are responsible for weak bass, and in a home studio nulls cause you to add too much bass to your mixes making them sound boomy everywhere else. But in square and cube shaped rooms the peaks can double up or triple, respectively, and be much more than 6 dB.

So in those rooms EQ really can help. It doesn’t reduce ringing, and it won’t help the nulls, but just lowering the level of the worst few low frequency peaks is a welcome improvement.

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About Ethan

Ethan Winer
Ethan Winer

Ethan Winer has been an audio engineer and professional musician for more than 45 years. His Cello Rondo music video has received nearly two million views on YouTube and other web sites, and his book The Audio Expert published by Focal Press is available at and through Ethan’s own web site Ethan is also a principal at RealTraps, a leading manufacturer of high quality acoustic treatment.

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