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[phusis]

Hi folks,

Don't know if this has been brought up before on these pages, but have any here heard of the Leedh algorithm for digital volume controls?

To quote:

Let’s rewind then to digital volume controls. For every 6dB of attenuation, they strip one bit. That obviously throws away resolution. The counter-argument, particularly for 64-bit digital volume code as one finds it embedded in software players like PureMusic and Audirvana (the latter recently released also for Windows), is that it doesn’t matter. With sixty-four bits, one could throw away well more than half and still be way ahead of the 16-bit game. Maybe yes, maybe no. Opinions diverge, also on what the perfectly happy versus detrimental amount of digital attenuation might be.

Joël had always found himself in the definite no camp after having been intimate with upscale preamps like the Rogue Audio Hera II, SMC VRE-1, VAC Renaissance, Angstrom Research Reference 2, Ypsilon PST-100, Spectral DMC-30, Robert Koda Takumi K10 and his resident Coincident Speaker Technology direct-heated 101D triode unit. To him, digital volume killed and flattened out the sound.

Until it didn’t. Enter the same Gilles Milot, founder of French firm Leedh. He had devised an algorithm claimed to be non-lossy regardless of attenuation depth. With Joël’s personal system having served extended A/Bs (DAC-to-amp direct using Leedh’s code versus some of his exotic/expensive preamps), he had never known how much distortion analog volume suffers by comparison to a truly lossless digital implementation.

Fast forward and Leedh’s code has gone commercial. One of the first hardware licensees is Soulution who now have it built into their 560 and 760 DACs. Engineered of Switzerland, previously ABC PCB and a core provider of advanced digital boards for companies like CH Precision, Nagra and Soulution, were vital in creating a demonstrator circuit board whereby Gilles Milot could run tests with Joël and later fly to Switzerland to visit Cyrill Hammer of Soulution.

At the Munich [High-End 2018] show, Joël and his reviewer colleague Jean-Marc Villafranca had an opportunity to conduct a private after-hours A/B in Soulution’s exhibit system. The Swiss had uploaded switchable firmware to their DAC to enable instant comparisons between their own digital volume controller and Leedh’s.

Longer story short, both reviewers were astonished. Despite his professed love of exotic preamps, Joël in fact now predicts the eventual but inevitable decline of this category of device. Application opportunities extend to streaming providers like Qobuz, Tidal and Spotify because the Leedh algorithm works just as demonstrably with MP3 files; video like YouTube; and iPhone & Co. In fact, a forthcoming Audirvana update is already said to include the Milot code.

But there’s still more. Our French inventor has also written his own on-the-fly upsampler which Joël found just as superior to the usual versions as the attenuation code. As he put it, it’s really most telling that a tech-driven company like Soulution who make and sell preamps with analog volume control would become one of the earliest adopters of the Leedh algorithm. According to Joël, the engineers at Engineered confirmed that to their knowledge, this form of digital attenuation has never been attempted before. It really does seem/sound like a bona fide breakthrough which is merely awaiting mass discovery by our industry at large. That’s, in fact, the reason why I’ve here recapitulated Joël’s feature on 6moons for the Darko.Audio readership. The more the merrier is the operative mandate here and being repetitive for once is a plus, not minus...

https://darko.audio/2018/05/kih-57-a-lead-on-leedh/

This is something I'd truly cherish as a volume option via JRiver. Please, admins, consider this...

[pschelbert]

yes, its discussed on aktives hören forum.

Seems just to be voodoo marketing of simple floating point 64-bit processing of volume which I guess MC already does.
Nothing new, just wrapped in nice words for marketing purposes.

Here:
https://www.aktives-hoeren.de/viewtopic.php?f=23&t=9890&hilit=leedh

[RK]

Despite his professed love of exotic preamps, Joël in fact now predicts the eventual but inevitable decline of this category of device.

Perhaps the writer is not fully aware of the full measure of tasks a good pre-amp performs. Its much much more than just volume control! The pre-amp is indeed a kind of interface actually. When source and destination are interfaced optimally then sound quality develops in a beautiful and engaging way.

Some brands may want to move to digital volume control. In some cases a good idea and in others its a  "cop out" - A good analog control is not only really expensive but also difficult to implement and may be space consuming as well. When done well however it is great. But nothing is perfect...

[Spike1000]

Perhaps the writer is not fully aware of the full measure of tasks a good pre-amp performs. Its much much more than just volume control!

Indeed it's a buffer as well.

They are simple, cheap, easy to implement and don't need to consume a lot of space.

Like people's understanding, nothing is perfect 

Spike

[pschelbert]

computer with JRiver and and active speaker-system or a audio-interface, poweramp, passive speaker  is all you need today for top quality audio.

No pre-amp needed, just an unnecessary complication and possibly quality compromising.

[michael123]

computer with JRiver and and active speaker-system or a audio-interface, poweramp, passive speaker  is all you need today for top quality audio.

No pre-amp needed, just an unnecessary complication and possibly quality compromising.

You are not an audiophile, uh?

We listen with ears, and whatever does good to them - appreciated
Sort of religion

Although I also have limits.. like audiophile switched power supplies for router (!) and 500$ ethernet cables.

[michael123]

Computer
http://www.6moons.com/audioreviews2/lampizator5/1.html

[JimH]

We listen with ears, and whatever does good to them - appreciated
Sort of religion

This is sort of a secular forum.

Please don't tell someone they are not an audiophile.

[pschelbert]

my moto is "reduce to the max".
Stuff you do not need is just potentially making trouble and adds cost.

Computer power is today very high with a low cost computer.
No need to tweak performance anymore. Avoids a lot of hassle and time lost.

Important: use ASIO drivers on Windows (any version). Mac have native drivers.

No noise versions: only no fan is a noiseless fan

Same with HD, only no HD (i.e. SSD) is a noisesless HD.

The way to have HD with high capacity is to use NAS over Ethernet. The NAS can be in another room, avoids disturbance.

Rather cheap tricks to have the highest quality audio today.

[kr4]

Please don't tell someone they are not an audiophile.

And do not tell someone that they are.

[dtc]

We listen with ears, and whatever does good to them - appreciated
Sort of religion

Seems pretty secular to me.

[RK]

Returning to the original thread focal topic

This is something I'd truly cherish as a volume option via JRiver. Please, admins, consider this...

I am sure many JRiver users rely quite heavily on JRiver internal volume control.
One beauty of JRiver is that it has the flexibility to suite wide ranging individual requirements. For those who want “bit perfect output” and run analog based volume etc, they covered. For those who run direct to power amp or poly amplification for complex active systems, they too are covered without the need for multi channel pre-amplification. Sweet!

The thread starter felt they had found something about a digital volume control system that is better than  all other digital volume systems and therefore brought it to the attention of the JRiver Team so they might look into it.
Always good!

As far as I understand the application of such DSP (a volume control) is about as simple and “text book style” as DSP gets. Come to think of it, only phase inversion or muting is simpler I guess.

Anyway, perhaps the JRiver DSP “gurus” could enlighten the thread starter with regards to JRiver volume implementation versus alternatives?   I personally am pretty sure JRiver has done as good a job here as can be done. And certainly if I had invented and patented a superiour volume DSP, my first customers would be the studios then broadcast producers. Well, one cent royalty for each channel fader and I would have a pocket full of tin!