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[d_pert]

Hi,

I did a search in this forum for the word "Loudness" and came up with zero.

It would be great to see a variable Fletcher-Munson Loudness Control / Plugin for MC14.

Does anyone remember this? It’s not even that “old”? I’m only 35!

In my opinion, this is a major and wonderful function for home audio music playback that existed on almost all decent stereo sets for about 40 years (?) and has mysteriously disappeared from the front panels, manuals and "general knowledge" it seems.

To be clear, this is a function separate from Volume ... although dependant on Volume. This also is not to be confused with “loudness” achieved through compression, multi-band or otherwise.

It is a volume-affected, variable compensation for the Fletcher–Munson Loudness Curve - in short that human hearing has different frequency responses at different SPL(s).

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

In practical application, there used to be a switch on stereos that would say "Loudness" and the circuit, when engaged, would overlay a compensating (opposite) curve - in step with the Volume setting and the amount of Fletcher-Munson effect at that volume level.

On more sophisticated sets, there used to be a Variable Loudness control – with a “default” position marked, but allowing the user to “dial in” the amount of compensation.

I’m not sure how these ubiquitous circuits knew the actual SPL in the room (they couldn’t have), but there must have been some brackets established arbitrarily, based on typical consumer loudspeaker sensitivities etc. And the Variable Loudness made it possible to be more accurate, I guess. Maybe it's simpler.

Indeed, some MC14 users might be piping their soundcard’s analog output through an integrated amp or receiver that has a Loudness control. However, in the last 15-17  years or so, across all the major brands, the function seems to have disappeared, and it would be great to enforce it right in MC14, to taste (variable).

Many users surely run straight into amplified speakers, or a pure amp, too.

There may be some controversy over whether this is relevant given today’s technologies – and there may be something I’m missing here about why “Loudness” has disappeared.

That aside, it was always a great, quick way to bring fullness, clarity and more fun to tons of recorded music and playback environments. Objective or Subjective ... it was a fun and effective tool!

Enough promoting now ... anyone want to pick up this idea? I’m no programmer.

[MusicHawk]

Excellent post. You're right, Loudness Curve behavior seems to be missing from newer gear, which somehow confuses digital purity with listenable quality. Lacking a Loudness Curve, music played on "modern" gear usually sounds thin at low volume and/or way too boomy at high volume.

Back in the day, Loudness Curve behavior was usually built into audio gear (typically switchable) and was the norm in car radios.

Playing back "flat" through an audio chain isn't actually a useful listening mode because the human ear is un-flat and the curve varies with volume, as plotted by Fletcher-Munson.

The tricky part of curving frequency response based on loudness -- to appear consistent to the human -- has always been calibration, as you say -- getting the curve-based adjustment correct for a given audio-chain, listening environment and range of volume levels.

The challenge is that the volume must be adjusted before or within the audio stage applying the curve, or the loudness circuit can't know to vary the frequencies. But I suspect that in lots of computer-based systems, the listening volume is adjusted outside the PC, at the external amp, since that is also where volume is adjusted if using the same amp (often a receiver) for other purposes such as CDs and radio (which also benefit from having loudness mode enabled). Therefore, the external amp is where the loudness adjustment must happen. (And it does for me because fortunately, I'm still using an older Sony amp that has a loudness mode. But when it dies, not sure what I'll find on the market).

So, if Loudness Control is provided as an MC DSP plug-in, how would it work in practice? Assuming it is possible for a listener to set-and-forget the volume of an external amp, and do all volume adjustments on the PC: Where does volume change happen in the PC's total audio chain? And where does it happen related to everything in MC's DSP chain?

[d_pert]

Hey thanks for the great feedback!

So I guess that:

a) the plug-in/feature would be 100% as meaningful as the old 'Loudness' button or knob if the user is using their computer as a digital volume control (using the application volume, not the Windows system master volume - but that many people do not to this (myself included)

b) with the plugin/feature being a variable control, it becomes more meaningful to people who leave their application and windows volume(s) at a constant level, although you'd have to be prepared to variably control it on a regular basis, along with your outboard volume control - the more obsessive of us would be making their volume adjustment into a two-step process!

However, what do you think of a variable control so that at least we have the option, and the ability to set some presets with names like, "background", "moderate", "house cleaning", ?

(Addition):

So, if Loudness Control is provided as an MC DSP plug-in, how would it work in practice? Assuming it is possible for a listener to set-and-forget the volume of an external amp, and do all volume adjustments on the PC: Where does volume change happen in the PC's total audio chain? And where does it happen related to everything in MC's DSP chain?

Perhaps it could be added to the "Effects" section of MC14 DSP Studio. I don't think it matters if it's sitting before or after Equalizer of Volume Leveling - because it's just cummulative addition. Hmm.

P.S. - Here's some other guys working on somthing similar elsewhere:

http://www.driverheaven.net/effects-dsp/101814-another-one-my-ideas-equal-loudness-contour.html

[MusicHawk]

Because it's entirely about human hearing, I think a Loudness Curve plug-in would have to be the final stage of DSP so it didn't mess up any processing happening before.

Presuming this DSP chain position, it would definitely require the user to control volume via MC and not the external amp. Is this likely?

Another problem with some modern gear and audio controls is ignorance of how humans perceive loudness. Classic volume controls are not linear in how they change the electronic volume, they are roughly logarithmic, which to a human seems like linear acoustic loudness adjustment. A proper volume knob is a mechanical potentiometer specially designed for audio. It varies resistance logarithmically as it is rotated. This same behavior is (or was) in almost every control that adjusts audio, including radio station control boards and recording studio consoles. In a device that lacks this behavior, we get the effect of turning the knob a lot but getting very little volume change, OR turning it a little and getting too much volume change. It's quite annoying and stupid.

[cncb]

Have you looked into Audyssey Dynamic Volume/EQ?  I don't know how it compares to what you are requesting but I think it does a pretty good job and can be had on relatively inexpensive receivers now.  There is also Dolby Volume which has just entered the scene.

[d_pert]

I actually use Audyssey ... it's different than what we're takling about ... but related in that you have to actually play test tones and use an omni test mic at multiple points in the room. I say I use Audyssey because it's the engine (licensed technology) inside the IK Multimedia ARC System:

http://www.ikmultimedia.com/arc/features/

...which runs great as a VST plugin in MC14.

Don't know about Dolby Volume though. Cool. Will research. Thanks.

Have you looked into Audyssey Dynamic Volume/EQ?  I don't know how it compares to what you are requesting but I think it does a pretty good job and can be had on relatively inexpensive receivers now.  There is also Dolby Volume which has just entered the scene.

[cncb]

I actually use Audyssey ... it's different than what we're takling about ... but related in that you have to actually play test tones and use an omni test mic at multiple points in the room. I say I use Audyssey because it's the engine (licensed technology) inside the IK Multimedia ARC System:

http://www.ikmultimedia.com/arc/features/

...which runs great as a VST plugin in MC14.

It doesn't appear that the ARC System has Dynamic EQ and Dynamic Volume which is relatively new technology and is in addition to/separate from MultEQ: http://www.audyssey.com/technology/dynamiceq.html

[rick.ca]

This is over my head, but I do miss that loudness button on my old receiver—for listening to music at low a low volume. I'm sure the dynamic range compressor on my current receiver does a much better job, but it's not a very accessible setting. I wonder if it's possible to achieve the same effect using custom equalizer presets. If so, what sort of adjustments would be made to an existing preset? Or is this redundant, as this is the purpose of an equalizer anyway? Maybe this explains why I appreciate a "rock" equalizer preset at low volumes, but at higher volume prefer it "flat."

[MusicHawk]

Rick:

Classic Loudness control is automatic in that it is directly tied to the volume control of the amp. As the volume control is turned up/down, the frequency curve is also changed, per the Fletcher-Munson curve, so the human ear perceives consistency.

It's a bit arbitrary, given variations in speakers and listening space, but once the EQ is set to the listener's preference, the automatic Loudness adjustment keeps the sound reasonably consistent for that listener in that environment.

So, to do this manually, you could set the amp to the typical volume levels (quiet, medium, blasting) and for each diddle with EQ to get what you like. Then when when changing volume, also change the EQ. Tricky but at quite likely worth the effort.

But as "d_pert" notes, it's idiotic that Loudness has been omitted from lots of audio systems. Digital revolution notwithstanding, the human ear hasn't changed at all. Of course, the loss of true music fidelity isn't noticed by people who think 128k MP3 sounds "better" or who want to add 1000 watts of bone-rattling bass to music.

[rick.ca]

Thanks for the explanation. If I understand correctly, I should be sending a constant volume to the amp and using it's volume control. I've been leaving the amp volume fixed and controlling it from MC (which, in turn, is controlled by my PC remote). I'd rather not have to use two remotes. Maybe I'll need to re-think that once I switch to a digital PC-amp connection (I'm currently using a USB DAC). That might induce me change the amp settings more frequently.

As things are now, I can't tell the difference between full system volume varied by the amp, and the reverse. Maybe The Doors don't provide the best test material. I'll have to experiment with different kinds of music.

BTW, the "dynamic range compressor" feature on my amp is part of the surround sound settings, so I suppose it's for a somewhat different purpose. According to the manual (I'm so confused, I'm RTFM!), "this parameter allows you to compress the dynamic range of the soundtrack based on the dynamic range information included in the Dolby Digital signal."

[MusicHawk]

I don't know about your specific gear, but in general, dynamic range, compression, and similar terms involves rapid adjustment of the overall audio stream, raising low levels and reducing high levels to provide a more narrow range of variation.

That's not related to Loudness Curve changes, which alter the EQ, such as by boosting bass at lower volume. In theory, Loudness adjustment is based on the level of audio being sent from the speakers to your ears, since it is the human hearing response that Loudness Curve attempts to help. So, whether audio is very uncompressed (lots of dynamic range/difference between quietest and loudest parts) or very compressed (quiet parts and loud parts are not far apart, and overall effect is "louder") doesn't matter much. It's the level at which it is played -- therefore the volume setting of the amplifier -- that should trigger Loudness Curve changes.

With a Loudness Curve circuit that can be enabled/disabled, play a given piece of music that has a "normal" but noticeable bass line or other sense of lower frequencies. At a loud volume -- rockin' the room -- switching Loudness on/off probably does little or nothing. But at low volume (background music allowing normal conversation), the bass level should change with Loudness on/off. That's more-or-less the desired effect. What it's really demonstrating is that the human ear doesn't hear the same at different volumes (literally the force of the air movement hitting the eardrum, often measured as Sound Pressure Level -- SPL), so a compensating circuit that applies a Loudness Curve can provide a more consistent listening experience.

In the good old days of analog audio -- source (CD player, turntable, radio receiver) to amp (with volume control and Loudness Circuit and "tone" controls) to speaker it was easy to get the right stuff to happen in the right places. With DSP and a mix of computer hardware and software and external gear, and several points of control, it's apparently difficult to be sure anything happens at the optimum point -- or worse, it could happen at a totally wrong point.

In MC14 I recently made an assumption that the new ability to order DSP plug-ins would help a particular situation, but Matt clarified that some stages are at fixed locations even if they seem to re-orderable. So it's still "iffy" to be sure what is happening and where it happens.

[rick.ca]

With a Loudness Curve circuit that can be enabled/disabled...

This is exactly the effect I was used to and miss from the "good old days." A simple button to push to make the necessary adjustment for hearing at low volume. At loud volumes, it had no discernible effect. For some range in between, it was obvious it was a distortion and should be turned off. The HK receiver I'm thinking of had no remote control, so having to turn loudness on/off while adjusting the volume was not an inconvenience. I wish there could be a software equivalent—perhaps one that could be set to be applied automatically below a set volume.

[MusicHawk]

Another complication to implementing Loudness Control is that DSP can do all kinds of things that didn't exist in classic analog, making it even harder to determine what to adjust, where in the chain to adjust it, etc.

For instance, I use AudioProc (AudioProc.ca), a wonderful DSP plug-in that provides all the processing used by radio stations, many, many different types of processing including multi-band compression and several stages of EQ and limiting.

One cool stage that can be activated is dynamic EQ, which diddles with audio on-the-fly to make different recordings, made at different times with different sounds, have more consistent sound. So a bass-light recording and a bass-heaving recording will both sound more bass-even. Dull sounding recordings will be brightened up, and too-bright toned down. Combined with the multi-band compressor stage, it really smooths out my huge eclectic music collection when I play it randomly, my favorite mode. Etc.

Of course, this is not for purists who crave the exact sound of the original recording, but so much of that is arbitrary or even flawed that radio stations use AudioProc (or similar) to polish there sound. I care nothing about purity for "correctness" sake, I want a crisp, strong sound that showcases the music.

I use AudioProc as an MC14 plug-in and love it, especially combined with MC's cross-fade aggressive at 1 sec, which is not actually a cross-fade at all (a while back I persuaded Matt to make it simply overlap without doing any fading). But, AudioProc is a tad pricey, so only for those who love the radio station sound. Note that it's officially a Winamp plug-in but works well in MC. It also gives much a much higher audio output from my PC (adjustable, along with everything else).

[rick.ca]

AudioProc is a tad pricey...

Well, the lite version is obviously for people like me, and $20 isn't that much. If I like the sound and it delivers the effect you describe without me being sucked into fiddling with things I don't understand, it might be a bargain. I'll give it a try when my new machine arrives.

[d_pert]

I just cheeked this thread and what a great assortment of input(s). Thanks everyone.

I think what's realistic to ask for is a Variable Fletcher Munson Loudness control linked to the software volume control, as a plug-in in the DSP Studio, which can store presets.

That way:

A) A person who uses software volume control can benefit from the auto-link to volume, and would probably find a pleasing position on the variable control which would suit them, with no further change to it because it scales the effect to the setting of the software volume control. They would no doubt have a “constant” setting for their outboard gear volume control(s) in this scenario.

B) A person who leaves their software volume controls at 100% (constant) and who wants to obsessively "tune in" the effect to his/her taste according to their outboard volume / real room SPL can.

C) A person who wants less of a hassle, but still wants to benefit from the effect would create presets for arbitrary, rough listening levels they define, such as "Background Reading" or "Background Party" and select one of these for the appropriate occasion.

Personally, I’m likely to be in group C.

With respect to location in the DSP chain, I would look to JRiver MC developers themselves to clarify the actual sequence positions of the DSP plugins. Indeed they have added reorderability to some extent, but certain modules are locked in position behind the scenes and so the graphic list reordering is somewhat misleading. They ought to put a little divider line at the bottom of the list and rack their fixed modules there ... like Output Format. The remaining, user orderable rack could have some note on the panel like “you can sequence these” – software developers have the better language

So what’s the next step to getting a plug-in such as this made? Do people just wait and see if a “real programmer” happens to see this thread and get excited by it?

Are there any candidates out there?

[gappie]

interesting thread. when i first read it i checked my 25 years old sony amp.. have loudness apperntly always on. would be interesting to hear the difference on my nearfield studio amps (active). i do think there are enough people using the internal volume.. with asio windows volume has no effect...

thanks for all the info.

 
gab