Single vs multiple measurements with Acourate digital room EQ

[asdf1000]

Hi @Archimago and @mitchco

 

Great book Mitch ! And great article Archi about Acourate:

 

http://archimago.blogspot.com/2019/10/2019-update-basic-acourate-dsp-room.html

 

Just wanted to ask if you do/did multiple measurements around the main listening position, with Acourate?

 

If so, can you share a guide on multiple measurements in Acourate?

 

If not, can you please explain why a single measurement is fine with Acourate?

 

I'm just using simple pair of passive speakers with no DSP crossover (yet).

 

Thanks!

[mitchco]

Hi @asdf1000

 

Here is a blurb from Uli from the Acourate forum:

 

"Acourate mainly uses the measurement at the listening position. This results in the best correction at thee sweet spot. But. because Acourate applies a different approach in the calculations the result is not only valid for a single position. So you can walk around and you will notice that the sound at other positions is not getting bad. The Acourate calculation avoids over-boosts by principle..

Dirac, Audyssey, Lyngdorf use different calculations by averaging multiple frequency responses. They need to do this to to also avoid over-boosts.

Despite the typical single point measurement Acourate allows you to do multiple measurements and to combine them by functions like
- averaging the frequency responses
- calculating the max. envelope for a bundle of frequency responses
- averaging multiple pulse responses"

 

I have a section in my book on the latter point on averaging multiple pulses called "Beamforming" and you can see the procedure and results.

 

For more of a technical explanation on the psychoacoustic filtering applied to the measurement, see my note on transient response analysis. Also in my book...

 

As you will note in my book, the section on design verification, I moved the measurement mic to 14 locations covering a 6ft x 2ft grid area that represents my couch listening area to verify the design of the correction filter. The correction filter design is based on a single analysis measurement. The results speaks for itself.

 

You may want to ask Uli and other Acourate users on the Acourate forum about their experiences as well.

 

 

[asdf1000]

10 hours ago, mitchco said:

You may want to ask Uli and other Acourate users on the Acourate forum about their experiences as well.

 

Thanks @mitchco !

 

I'm also interested if @Archimago tried single vs multiple measurements points and what he found.

 

[jrobbins50]

@mitchco, is the same true for why only a single measurement is required for Audiolense?  JCR 

[mitchco]

Hi Jeffrey, yes, same for AL. You can find an equivalent analysis chart in the AL manual. See page 41 of the PDF help file.

 

Acourate and Audiolense are the only DSP software I know that employs this type of psychoacoustic filtering during the measurement/analysis process.

 

Both software also has the capability for multiple analysis measurements. I have done both (to death!). At this level of (SOTA) performance, I encourage folks to try both (i.e. single analysis versus multiple) and let your ears decide which one you prefer, as the frequency and timing response are pretty much the same regardless of which method is chosen.

[asdf1000]

1 hour ago, mitchco said:

Acourate and Audiolense are the only DSP software I know that employs this type of psychoacoustic filtering during the measurement/analysis process.

 

Dirac Live is a bit of a black box, so it's possible they are doing something similar but only Dirac would know for sure?

 

[mitchco]

On 5/30/2020 at 11:15 PM, asdf1000 said:

 

Dirac Live is a bit of a black box, so it's possible they are doing something similar but only Dirac would know for sure?

 

Answer is in post 2.

[asdf1000]

43 minutes ago, mitchco said:

Answer is in post 2.

 

Hi @mitchco, I did see "Dirac, Audyssey, Lyngdorf use different calculations by averaging multiple frequency responses. They need to do this to to also avoid over-boosts"

 

But is that the only reason Dirac takes multiple measurements? Only to avoid over-boosts?

 

I'm not sure how Uli would know all the reasons, unless Dirac have somewhere explained what they're doing.

 

Dirac has always seemed a bit 'black box' though (to me).

[mitchco]

Some of us have taken extensive measurements after correction for each of the DSP products listed... multiple times on multiple systems. It is not too hard to figure out what is going on...

 

Dirac's technology is different using a combo of IIR and FIR filters as discussed in this article, which also links to their whitepaper on their tech: 

 

Why not ask Dirac directly?

 

Where are you in your DSP journey?

[asdf1000]

On 5/31/2020 at 1:13 AM, mitchco said:

"Acourate mainly uses the measurement at the listening position. This results in the best correction at thee sweet spot. But. because Acourate applies a different approach in the calculations the result is not only valid for a single position. So you can walk around and you will notice that the sound at other positions is not getting bad. The Acourate calculation avoids over-boosts by principle..

Dirac, Audyssey, Lyngdorf use different calculations by averaging multiple frequency responses. They need to do this to to also avoid over-boosts.

 

I saw Dirac responded to this comment of Uli: