Some comments from Floyd Toole about room curve targets, room EQ and more

[Geert]

Like I said, it's a matter of taste. That is why people buy different speakers.
Besides, I find the Harman preference assessment flawed.

Don't know what so offensive about these curves. Looking at the average curve, the 'All listeners' curve, it's very close to the 'Predicted steady state response in a typical reflective room' curve. So the main takeway is that a speaker that measures flat in anechoic conditions is a good starting point. Nothing shocking, and you (or the designer) can finetune as you like.

 

[Geert]

I'm just using anechoically flat EQ'd speakers (Listening Window EQ) based on Amir's measurements of my speaker, and I've done measurements at my listening position after EQ and it just happens to follow the downward curve of Harman quite accurately, and the bass peaks generally line up with Harman too without any room EQ.

That' s exactly what I mean. Start from anechoic flat, correct for room modes, maybe apply some 'equal loudness' compensation and a bit of personal preference and the result will be close to the house curves. No need to get obsessed with these curves and to try it the other way around.

 

[Robbo99999]

That' s exactly what I mean. Start from anechoic flat, correct for room modes, maybe apply some 'equal loudness' compensation and a bit of personal preference and the result will be close to the house curves. No need to get obsessed with these curves and to try it the other way around.

Some curves are easy to obsess on, normally on people though! Yeah, don't obsess on room curves!

 

[Frgirard]

Some curves are easy to obsess on, normally on people though! Yeah, don't obsess on room curves!

B&K has been defined a target different of Harman with a panel of people.
So irrelevant than Harmann curve and others

 

[Geert]

B&K has been defined a target different of Harman with a panel of people. So irrelevant than Harmann curve and others

Again a curve that sits somewhere in the middle of the Harman curves, so how can you conclude it's all irrelevant? That curve is almost 50 years old by the way, so seems normal to me that the results of recent studies using more advanced speakers differ slightly.

 

[tuga]

Again a curve that sits somewhere in the middle of the Harman curves, so how can you conclude it's all irrelevant? That curve is almost 50 years old by the way, so seems normal to me that the results of recent studies using more advanced speakers differ slightly.

The methodology used in the B&K tests is different too (https://www.bksv.com/media/doc/17-197.pdf).

 

[Geert]

The methodology used in the B&K tests is different too (https://www.bksv.com/media/doc/17-197.pdf).

Absolutely right. Which means these different studies don't contradict but lead to advanced insights.

 

[JoachimStrobel]

Most definitely!



I disagree. It's after all a matter of taste. People are obsessing too much with this house curve thing and some may end up disappointed.

This goes much beyond the „house“ curve which just happens to illuminate the issue.

 

[hibikijin]

First post here, hi everyone. One point in Toole`s book is the need for an (easy) loudness correction/control. Beyond personal preferences, if I understood correctly, no matter how flat or house curve adjusted (or not), the way we perceive/hear the bass (<200Hz) is much dependent on level/volume the program is actually played. So if an engineer heard and adjusted for a good bass balance in the final recording it was done at a certain level, say, 80db. Toole says in his book whenever we hear it at a different level, we will have a different perception of the bass (mainly) levels (explained by the difference of equal loudness contour curves, ELCC, at specific phons). The figures attached are from his book reflecting those adjustments. It seems that a static curve (house or otherwise) is a poor attempt, and just applies to the average difference/listener preference.

What I am looking for is a dynamic equalizer or loudness control or vst filter/dsp hardware/dynamic convolution or even an analog one that works dynamically, at play time time, adjusting the loudness based on the volume level and those ELCC. If software, it could be plugged into JRiver, Roon or into another player app. Basically it has a settable reference level, and from there it adjusts according to the curves and volume. Does it make sense? Anyone aware of such a device/app/plug-in?

 

[digitalfrost]

EqualizerAPO has a module for that, but I don't like it much.

 

[hibikijin]

EqualizerAPO has a module for that, but I don't like it much.

Thanks, I will have a look..

 

[beaRA]

First post here, hi everyone. One point in Toole`s book is the need for an (easy) loudness correction/control. Beyond personal preferences, if I understood correctly, no matter how flat or house curve adjusted (or not), the way we perceive/hear the bass (<200Hz) is much dependent on level/volume the program is actually played. So if an engineer heard and adjusted for a good bass balance in the final recording it was done at a certain level, say, 80db. Toole says in his book whenever we hear it at a different level, we will have a different perception of the bass (mainly) levels (explained by the difference of equal loudness contour curves, ELCC, at specific phons). The figures attached are from his book reflecting those adjustments. It seems that a static curve (house or otherwise) is a poor attempt, and just applies to the average difference/listener preference.

What I am looking for is a dynamic equalizer or loudness control or vst filter/dsp hardware/dynamic convolution or even an analog one that works dynamically, at play time time, adjusting the loudness based on the volume level and those ELCC. If software, it could be plugged into JRiver, Roon or into another player app. Basically it has a settable reference level, and from there it adjusts according to the curves and volume. Does it make sense? Anyone aware of such a device/app/plug-in?

Most modern AVRs have a similar feature. It's called "Dynamic EQ" on Audyssey equipped receivers and "YPAO Volume" on Yamaha receivers.

 

[dasdoing]

EqualizerAPO has a module for that, but I don't like it much.

Does it use the ISO curves? I have found it in E_APO, but haven't found any documentation

 

[nathan]

Dolby has a version as well, included in a last generation Anthem receiver I have. But if one uses ATMOS speakers it disengages. Rather effective otherwise.

 

[Robbo99999]

The max is 20 filters, although the 8 remaining ones are not easy to configure.
In the MiniDSP crossover module, you can choose advanced, and type free text. This text can be a set of 8 biquad filters as exported by REW.

You must enter 8 filters. It doesn't accept less. Therefore you need to fill the missing ones with null biquads (REW can export an example).
The filters must be numbered from 1 to 8. Therefore you will have to change the numbers exported by REW.
The last row must not have a comma at the end. All other rows must have a comma.

I don't know how MiniDSP deals with a positive correction followed by a negative one (internal clipping ?), therefore I always put negative correction in the first module, and positive corrections in the last.

Edit : the identity biquad is:
biquad1,
b0=1.0,
b1=0.0,
b2=0.0,
a1=0.0,
a2=0.0

This is awesome, worked perfectly, thankyou! That is a substantial increase in value, from 12 filters up to 20!

 

[Tom.O]

View attachment 46607
Does it represent single channel preferred curve or both playing together? Ideal phase alignment in the base region gives 6dB+ for L+R. If these curves are for single channel then "all listeners" curve will be +12dB at bass region for music where most of Low freq are mixed in mono.

 

[ernestcarl]

View attachment 46607
Does it represent single channel preferred curve or both playing together? Ideal phase alignment in the base region gives 6dB+ for L+R. If these curves are for single channel then "all listeners" curve will be +12dB at bass region for music where most of Low freq are mixed in mono.

I think I may have asked about this before... don’t recall if anyone answered, but my guess is that it’s for a single speaker. Much of the speaker preference tests have been done in mono.

 

[nathan]

It's the total energy in the room. If you are listening with one speaker, it's one speakers' energy in the room. If you are listening with ten speakers, it is the sum of them in the room. Similar to the Sound Power in the CEA 2034 spec (aka, Spinorama).

 

[thewas]

View attachment 46607
Does it represent single channel preferred curve or both playing together? Ideal phase alignment in the base region gives 6dB+ for L+R. If these curves are for single channel then "all listeners" curve will be +12dB at bass region for music where most of Low freq are mixed in mono.

Mind you the addition of 2 loudspeakers gives usually only 3dB extra bass compared to the higher frequencies as the addition in the bass is closer to coherent like you write (+6 dB) while on the other frequencies not (+3 dB).

 

[Dj7675]

Special thanks to @thewas for putting these Floyd Toole comments about room curves in one spot. He was very generous with his time explaining things and seeing it all together is a very interesting read.