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[Mikkel]

Hi jriver team,

I got a bit inspired while reading this article: http://www.anstendig.org/EQ.html (Sound equalization in relation to the way we hear).

... and wanted to ask if you would be interested in implementing something like a loudness function in jriver. That is, a volume adjusted dynamic eq-curve (fletcher-munson curve), which will help maintain the sonic balance and quality while listening at different volumes.


Best regards,

Mikkel

[Matt]

I'm definitely interested.

I've thought about this in the past, and the sticking point is that Media Center doesn't really know the actual volume you're receiving since the outboard amplification could be at any level.  Media Center can look at the volume slider, but that only correlates to decibels if a user uses Internal Volume. 

To do a really elegant job, it'd be best to know the exact level at your ears.

It's possible I'm making it too hard, and that a poor man's version of Loudness that has on/off or low/high/off might be enough.

[InflatableMouse]

I've often thought about features like auto-volume, loudness and several other things that you could do if MC used a microphone. It will require some calibration but I don't think that needs to be anything fancy. You could use it to measure the volume and regulate this loudness feature, but also stuff like lowering volume a bit if the mic deteced conversation.

[Mikkel]

Hi Matt,

Glad to hear you find the idea interesting. I agree with your concerns regarding the external volume settings. Implemented as per its purpose, a loudness function works best for people using internal volume and a mic or sound pressure meter to measure the reference level.

The advantage for those of us willing to do so (and who already use a mic for convolution) it will be a huge leap forward in perceived sound quality. For those who aren't willing I don't think they really care too much about the function in the first place.

I'm unsure if a simple version will work because of the acoustic/physical premisses of our hearing but I do understand you if you choose the simple version.


Best regards,
Mikkel

[hulkss]

To implement a "loudness button" correctly, each speaker level must be adjusted so that a -20 dBFS pink noise signal produces 83 dB sound pressure level at the listening position (volume gain at 100%). This is measured with a wide-band sound pressure level meter, C-weighting, slow response. A cheap spl meter (under $50) will do the job.
Now when you set JRiver internal volume to 100% you will get reference level volume in the seats if the source recording was made to "specification". From this reference point, a proper loudness function can be implemented as the MC internal volume setting is reduced.

Now comes the problem. Most audio tracks and many video recordings do not follow any level setting standard. In addition audio tracks vary in content and are processed in ways that affect the perceived loudness. To remedy this, the "reference level" for every audio track (including videos) needs to be determined. Knowing this reference level, the digital gain can be adjusted so all audio tracks are the same loudness at 100%. Much like using ReplayGain.

Today, this process should be done to the EBU R 128 recommended method. Software for this is in the public domain.
Please see my posts in this thread: http://yabb.jriver.com/interact/index.php?topic=69618.0

The subwoofer is another potential problem area if you are not using MC or an external processor for bass management. The subwoofer channel must be set relative to the front center speaker to a level 10 dB higher using a real time analyzer (see link). http://www.film-tech.com/warehouse/manuals/TN99051701.pdf

[nwboater]

Back in the 'good old days' many HiFi Receivers and preamps had a 'Loudness' control. Often times it was just a push button that switched in the 'Loudness' function. The more elegant ones had two concentric knobs, one for volume and one that increased the Loudness effect. Actually I'm not positive I remember exactly how they worked, but it was something like that.

Now probably only a small percentage of us audio nuts are going to use a calibrated mike to setup the system for proper Loudness, if MC had the capability. But if there could also be some kind of slider that would set the 'gain' of the loudness function then those that don't have a calibrated mike and and still want to use it just set the 'gain' by trial and error listening to music. That's how we did it on the old equipment and for many it was much better than not having 'Loudness' available. And of course an easy way to turn Loudness on and off is also needed.

Cheers,
Rod

[hulkss]

Now probably only a small percentage of us audio nuts are going to use a calibrated mike to setup the system for proper Loudness, if MC had the capability. But if there could also be some kind of slider that would set the 'gain' of the loudness function then those that don't have a calibrated mike and and still want to use it just set the 'gain' by trial and error listening to music. That's how we did it on the old equipment and for many it was much better than not having 'Loudness' available. And of course an easy way to turn Loudness on and off is also needed.

I disagree, almost every home theater receiver now comes with a calibration microphone. Buying a cheap spl meter for use with your PC is not a big deal. I use a PC and MC to be better than a receiver, not worse.

The EBU R 128 method I suggest could be automatic (it does have to prescan the audio files like replay gain). Then you just "push the loudness button" when desired. If you do not scan the audio to set a reference level then you will be adjusting the loudness almost every track to get it right.

Audyssey uses an adjustment to move the onset of the loudness function to different gain levels because they do not have the advantage of being in an HTPC. They move the start point up to  15 dB in 5 dB increments. https://audyssey.zendesk.com/entries/73283-dynamic-eq-and-reference-level

[nwboater]

I disagree, almost every home theater receiver now comes with a calibration microphone. Buying a cheap spl meter for use with your PC is not a big deal. I use a PC and MC to be better than a receiver, not worse.

The EBU R 128 method I suggest could be automatic (it does have to prescan the audio files like replay gain). Then you just "push the loudness button" when desired. If you do not scan the audio to set a reference level then you will be adjusting the loudness almost every track to get it right.

Audyssey uses an adjustment to move the onset of the loudness function to different gain levels because they do not have the advantage of being in an HTPC. They move the start point up to  15 dB in 5 dB increments. https://audyssey.zendesk.com/entries/73283-dynamic-eq-and-reference-level

I don't think I was very clear in what I would like for MC. So here it is:

1. The ability to use a calibrated mic per hulkss method.

2. A means for those who don't have, or want to bother with a calibrated mic to still enjoy a loudness function. It will need a 'gain' adjustment and will definitely be less than ideal. I do think that this method is still better than nothing, and of course it's up to the user whether or not to use it.

Cheers,
Rod

[Matt]

Does anyone want to take a crack at how to parameterize this?  I mean, what filters would do a nice job of approximating the Flethcher-Munson or ISO 226:2003 curves?

Image here:
http://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves

I would think you'd assume the curve was baked into the mastering, so you'd only want to look at the _difference_ in the ISO 226 curves between the reference level and lower levels (instead of correcting completely for the curve).

[nwboater]

Does anyone want to take a crack at how to parameterize this?  I mean, what filters would do a nice job of approximating the Flethcher-Munson or ISO 226:2003 curves?

Image here:
http://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves

I would think you'd assume the curve was baked into the mastering, so you'd only want to look at the _difference_ in the ISO 226 curves between the reference level and lower levels (instead of correcting completely for the curve).

Not a clue how to help you Matt, but sure glad you are taking a serious look at this.

Thanks,
Rod

[Mikkel]

Hi hulkss,

I would have thought you could take any measurement level since the behaviour of the curve as sound pressure increases or decreases is given by the principles in the flether munson curve; hence if you calibrate at 70dbc and turn up the volume to 83 dbc you would get the same curve as if you did it the other way around.

But then I'm no pro so I'll accept any correction to above :-).


Best regards,
Mikkel

To implement a "loudness button" correctly, each speaker level must be adjusted so that a -20 dBFS pink noise signal produces 83 dB sound pressure level at the listening position (volume gain at 100%). This is measured with a wide-band sound pressure level meter, C-weighting, slow response. A cheap spl meter (under $50) will do the job.
Now when you set JRiver internal volume to 100% you will get reference level volume in the seats if the source recording was made to "specification". From this reference point, a proper loudness function can be implemented as the MC internal volume setting is reduced.

[Mikkel]

Now comes the problem. Most audio tracks and many video recordings do not follow any level setting standard. In addition audio tracks vary in content and are processed in ways that affect the perceived loudness. To remedy this, the "reference level" for every audio track (including videos) needs to be determined. Knowing this reference level, the digital gain can be adjusted so all audio tracks are the same loudness at 100%. Much like using ReplayGain.

Above quote from hulkss point is I believe very important. A spectrum analysis would be required for each track (or perhaps album) so that it can be determined how the track's curve matches one of the shapes in the equal-loudness-diagram. By doing this comparisson it can be established at what level the track is intended to be listened to.

I don't know why we love our hobby. It is like pandoras box! :-)


Best regards,
Mikkel

[Mikkel]

Hmm, I suppose my last idea isn't that great after all. Each genre has its own spl curve. One wouldn't want to mess with that, I guess. Still, hulkss has a good point in that it is a problem that there is no standard on mixing and mixing levels, so we are left a bit in the dark, I guess.

About the "eq" curve for different genres: http://www.musiciansfriend.com/browse/article.jsp?mediaId=m710525

[Matt]

I think this is a case where 'pretty good' is still better than nothing.

I mocked up a system that links to the Internal Volume slider.  It's flat at 100%, then corrects as you turn down.  It does sound more neutral.

I'm not sure if it makes sense as a DSP in DSP Studio, or if it's just an option like 'Volume Protection' in the volume menu.  I think it only really makes sense as an option for users that use 'Internal Volume', so this is an argument for putting it in the volume menu.  There's also the question of allowing the strength to be adjusted and/or setting a reference level.

Advice welcome.

[nwboater]

I think this is a case where 'pretty good' is still better than nothing.

I mocked up a system that links to the Internal Volume slider.  It's flat at 100%, then corrects as you turn down.  It does sound more neutral.

I'm not sure if it makes sense as a DSP in DSP Studio, or if it's just an option like 'Volume Protection' in the volume menu.  I think it only really makes sense as an option for users that use 'Internal Volume', so this is an argument for putting it in the volume menu.  There's also the question of allowing the strength to be adjusted and/or setting a reference level.

Advice welcome.

Other than tagging and housekeeping we do everything in Theater View. Our usage varies from Video (movies, etc) to background music to audiophile listening. So it would be very helpful to have some way of turning Loudness on and off in Theater View. It would be very cumbersome to have to go back to Standard View on our separate monitor just to do that.

As a few of us have mentioned above there should be some way of adjusting the 'strength'. And that's where you can go from real simple to quite complicated. But I agree that 'pretty good' is better than not at all.

Thanks,
Rod

[hulkss]

I mocked up a system that links to the Internal Volume slider.  It's flat at 100%, then corrects as you turn down.  It does sound more neutral.

I'm not sure if it makes sense as a DSP in DSP Studio, or if it's just an option like 'Volume Protection' in the volume menu.  I think it only really makes sense as an option for users that use 'Internal Volume', so this is an argument for putting it in the volume menu.  There's also the question of allowing the strength to be adjusted and/or setting a reference level.

Advice welcome.

Just put in a means to set the "Flat point". At "100% flat point" it would be like you have it now. At 90% flat point the loudness control would be flat at 90% and above. This way a user can tune it for his system, like the old concentric knob that was mentioned.

[mojave]

The current reference level setting is more for movies since they are supposed to be mixed to the same standard. Music is mixed louder a lot of times. In my Movie zone, I might want the loudness button to be set the same as the reference level. However, in my Music zone I might want it set lower. Therefore, I think it should have its own "flat point" setting, as hulkss puts it.

I would like to see the setting in the volume menu with the other internal volume control settings.

[hulkss]

More info

http://www.sengpielaudio.com/Acoustics226-2003.pdf

[Matt]

Next build:
NEW: 'Loudness' that applies (roughly) the ISO 226:2003 loudness correction curve as you turn down the volume to provide a more natural volume (requires using Internal Volume, reference level of Internal Volume defines the base line, no correction is applied at volumes above baseline).

[jmone]

All I now need is the "Stereo Wide" switch and then it is "Party Like It's 1985"! 

[Mikkel]

Next build:
NEW: 'Loudness' that applies (roughly) the ISO 226:2003 loudness correction curve as you turn down the volume to provide a more natural volume (requires using Internal Volume, reference level of Internal Volume defines the base line, no correction is applied at volumes above baseline).

Great news Matt, thank you very much for taking the time to implement this feature.


Best regards,
Mikkel

[dean70]

All I now need is the "Stereo Wide" switch and then it is "Party Like It's 1985"! 

Stereo wide was a great function back in the 80's  Using the modern version: Ambiophonics DSP (hint, hint).

[drmimosa]

Thanks for developing this feature, I've rigged a parametric EQ to accomplish a similar effect for one of my plackback zones, automating this will make it even better!

Look forward to the new build...are we talking Christmas or Hannakah?

[Mikkel]

Hi again Matt,

I was wondering if you would elaborate a bit on how you have modelled the loudness-function? I was reading an interesting topic at hydrogen-audio and got curious on how you've done it. The topic is here http://www.hydrogenaudio.org/forums/index.php?showtopic=92822&view=findpost&p=791336

EDIT: Notice the discussion going on between "splice" and "dc2bluelight" in post 33 and post 34. I'm still digesting but it seems dc2bluelight has the long straw in the debate.


Best regards,
Mikkel

[StFeder]

Stereo wide was a great function back in the 80's 

Isn't  DSP-Studio -> Effect -> Surround Field   very similar to this?!

[Matt]

I was wondering if you would elaborate a bit on how you have modelled the loudness-function? I was reading an interesting topic at hydrogen-audio and got curious on how you've done it. The topic is here http://www.hydrogenaudio.org/forums/index.php?showtopic=92822&view=findpost&p=791336

Sure.  It's a rough approximation of the differences in the ISO 226:2003 curves as you come down from a reference level.

Roughly, you turn the bass down about half as much as the rest of the signal below the reference level.  There's also a similar, less severe correction for the high frequencies (>8 kHz).

You might play pink noise (Tools > Advanced Tools > Create test clips...) and DSP Studio > Analyzer to see what happens as you change the volume.

[jmone]

I'm still pumped for Stero Wide!

[Mikkel]

Hi Matt,

Congrats on the implementation. It is a huge improvement on the sound of both music and movies.

I ran into a bit of a head-ache with my amp, though. When I turn it to 0db (generating a SPL of 82dBc) I hear static noise from my stupid computer.

Turning the amp volume down to -10 (72 dBc) works but then I guess I'm not alligned with the loudness curve (?).

So I wanted to suggest a function where I can manipulate the internal reference level (0db) to know that my sound pressure level (spl) at my listening position is let's say 65 dBc or whatever I find suitable. MC would then apply the proper loudness for that spl. It would require, though, that the internal volume when turned above 0db continues to adjust the loudness curve until reaching no correction.

Or is it already possible to overcome this problem somehow?


Best regards,
Mikkel

[Matt]

So I wanted to suggest a function where I can manipulate the internal reference level (0db) to know that my sound pressure level (spl) at my listening position is let's say 65 dBc or whatever I find suitable. MC would then apply the proper loudness for that spl. It would require, though, that the internal volume when turned above 0db continues to adjust the loudness curve until reaching no correction.

Does setting the reference level for Internal Volume in Options > Audio > Volume help, or is that the opposite of what you need?  Loudness does key off this reference level and only makes corrections below 0dB.

[JustinM]

I just wanted to confirm that the loudness was being added before my DSP setting.

[Matt]

I just wanted to confirm that the loudness was being added before my DSP setting.

Loudness is applied at the same time as Internal Volume (before DSP effects).

You can look in 'Audio Path' to see the complete signal path including changes and the order they occur.

[Mikkel]

Does setting the reference level for Internal Volume in Options > Audio > Volume help, or is that the opposite of what you need?  Loudness does key off this reference level and only makes corrections below 0dB.

Hi Matt,

Thank you for your interest in the topic.

I don't think that is what I need - I'm not currently at home so I'll have to try. But as I understand it the reference level is equal to no loudness correction. If I set my reference level to e.g. 60 dBc no loudness correction is applied, when in fact it should represent the ?60 phon? on the loudness curve. So a way to match the reference level with a given phon level is what I need... if that makes sense?


Best regards,

Mikkel

[Mikkel]

"EDIT": The more realistic scenario in my case is that I'm calibrating the reference level for 72dbc instead of 82 dbc to avoid the static noise of my pc. What is then required is to tell MC internal volume that at reference level it must adjust the loudness to 72db on the loudness curve instead of no correction.

[hulkss]

Per current standards you would set reference level to 83 dB (sound pressure level) C weighting, slow measurement in the listening position. This is with a pink noise source at -20dBFS playing through a single channel. The level should be set by changing analog gain in the system with digital volume at 100%.

There will now be no loudness correction when you have your audio cranked up to play with 103 dB peaks (100% digital volume setting, 0 dBFS digital signal). With typical program material the average level will be around 90 dB.

For me, this setting will get loud enough to enjoy a concert DVD. It is about 10 db below a real concert. If you want to reach full rock concert volume, do the same setup with digital volume at -10 dB and set the loudness reference level to -10 dB.

[Mikkel]

Hulkss: Indeed that would be the correct way. Some (like me) may have reasons, though, for not calibrating at 83dbc at -20dbFS. There is no technical reason why this shouldn't be possible and still get the advantage of proper equal loudness correction, though. Or what do you think? :-)


Best regards,
Mikkel

[hulkss]

Hulkss: Indeed that would be the correct way. Some (like me) may have reasons, though, for not calibrating at 83dbc at -20dbFS. There is no technical reason why this shouldn't be possible and still get the advantage of proper equal loudness correction, though. Or what do you think? :-)


Best regards,
Mikkel

Just set the loudness reference to a point that is about as loud as you ever listen to for a few songs or so. No problem if it then sounds good to you.

[Mikkel]

Just set the loudness reference to a point that is about as loud as you ever listen to for a few songs or so. No problem if it then sounds good to you.

Agree, but I don't think it is possible to adjust the loudness reference at this point? If not that is what I've been asking for in the above posts.


Best regards,
Mikkel

[Trumpetguy]

Would DSP Studio be a more natural home for loudness? But still zone specific, of course.

[Matt]

Would DSP Studio be a more natural home for loudness? But still zone specific, of course.

Maybe someday.

Since Loudness is only available with 'Internal Volume', and only some users run in this mode, we felt it would be best to not make it too prominent at this point.

[Trumpetguy]

Maybe someday.

Since Loudness is only available with 'Internal Volume', and only some users run in this mode, we felt it would be best to not make it too prominent at this point.

I see that point. Now I'm just looking forward to have some time for myself to check out whether I am able to hear (and like/not like) the effect. It is certainly so that volume needs to be at a certain level before the "warmth" and "natural sound" is there, and volume limitation tend to be a requirement in everyday listening. A couple a years ago someone made me aware of the frequency perception curves, but I have never linked it to the loudness button on my NAD 80's amplifier. The only thing was that it should be used with some care and that audiophiles did not like it. It created facial contractions in much the same way as when the word "equalizer" was uttered.
 

[nwboater]

.................The only thing was that it should be used with some care and that audiophiles did not like it. It created facial contractions in much the same way as when the word "equalizer" was uttered.
 

I'm a Semi-Audiophool and I really like it. My wife, who isn't, also likes it a lot. It may partially depend on the capabilities of your woofers/sub.

So thanks again JRiver for implementing it.

Rod

[drmimosa]

This feature is really great. Very natural sounding, improves the quality and quantity of bass at lower volumes. In addition, the cutoff point (reference volume) is seamless. Works equally well on an expensive sytem and a not-so-expensive system.

Great work, and many thanks.

Merry Christmas and Happy Holidays to all at JRiver. Hope you get a good break, you all deserve it!!!

[Trumpetguy]

I'm a Semi-Audiophool and I really like it. My wife, who isn't, also likes it a lot. It may partially depend on the capabilities of your woofers/sub.

So thanks again JRiver for implementing it.

Rod

Promising :-) I like the title "Semi-Audiophool". Sort of describes myself quite well...

[Mikkel]

Fixed the static noise issue. Turned out to be the integrated GPU that was causing static noise.

Bought an emi-shielded ATI 6450 fanless gpu and noise has been brought to a minimum.


Best regards,
Mikkel

[ghostler911]

hey man if you use this isn't it like u use kmixer?
& what about the latency man? ?
How professional is this filter man?
please reply so I may choose awesome settings!
Good day!