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Chris Kyriakis – who is “Mr Audyssey” confirmed in a post in the FB-group “Audyssey Tech Talk” that the internal sampling used by the Audyssey algorithms, in todays implementation in Multicahnnel Receivers or AVR´s is sampling at 48 kHz.

That implies that using higher bandwidths of the inputmaterial, like SACD, DSD or even high bandwidth MP3 is useless, when it comes to being better than the same material in bandwidths of 48 kHz. Now the only thing getting close to that is CD-material of 44.1 kHz sampling.

Chris states the following: “The processing power required for audio algorithms increases with sampling rate. Going from 48 kHz to 96 kHz doubles the requirements. For this reason, AVR makers limit the processing sampling rate to 48 kHz for Audyssey (and other algorithms). The alternative would be to add another DSP chip, but that increases the cost significantly so they have not done it. There is nothing in the Audyssey tech that limits the sampling rate. In fact, the version running in all IMAX theaters is at higher sampling rate because they have a more powerful processor.“

You can read the whole posting at: https://www.facebook.com/groups/audysseytechtalk/permalink/9723992454281620

Reading the link, requires Your free membership of the group.

My thoughts of this is, that its true what Chris says, that HW was expensive when Audyssey was introduced some 20 years ago. But DSP (digital processors) have become MUCH more powerful since then. Think how much Intel PC-processors have evolved in 20 years….

So WHY have not manufacturers of AVR´s with Audyssey technology, stepped up the sampling rate to match at least DSD 64, which by the way is whats SACD is using? Where are Denon/Marantz, Integra, NAD, Onkyo/Pioneer and others on this, with modern DSP-chips?

And where is Dirac on this? They have never revealed the sampling rates used? Are they fixed as with Audyssey, or dynamic, depending on the bandwidth of the material? And is 16-bits words, as from CD, the standard with all DRC-algorithms?

And why did Audyssey choose 48 kHz, at a time (20 years ago) when 44.1 kHz was used by almost all digital material (eg CD). The resampling from 44.1 to 48 kHz introduces dist, thats for sure, but how much? I cant find any reliable papers on this subject?

I am sure I will be back on this subject again!

A year has passed, I was busy to finish several comittments and business projects, You can read more about what I do in my businessblog at: https://rationellametoder.se/

Now I am ready to put energy into perhaps my greatest interest again. DRC!

I still feel that DRC is the single most valuable component, after the speakers, to make a Hifi-system “sound like a million bucks!”.

Perhaps I will include my knowledge about decision analysis from my business, into a comprehensive tool to decide for each of You out there, what is the best choice for You to improve in a given situation?

My plan is now to get an agreement with suppliers of DRC, to lend me DRC-products to test against each other, to help YOU my dear followers, to choose the best products for You. I will start with finding a supplier that can offer the blog a DRC-multichannel product, that can be the long term reference product that other products will be tested against.

I am contacting serveral manufacturers and their local agents here in Sweden, to that end. It will take some time, but the objective is to get this going sometime in the new year.

The testsituation will to begin with have access to multiple speaker combinations. With everything from two channel Hifi to multichannel cinema setups.

Including, Altec Valencias with Tangerine drivers and JBL 077 added to the tops. Klipsch Palladiums. Velodyne DD18 sub. Kef KHT 2005.2 with Sub, Supreme 28´s a.o. Revox A77 HS with mastertape copies from OPUS3, Nakamichi Dragon, Mitchell Prisma turntable, Kenwood LM07 monoblock amps when other than built in amps are needed.

I often wondered how amp-producers implements the conversions back and forth from Material (like vinyl or CD) to DRC (like Audyssey, Dirac and Trinnov a.o.) to speaker output.

How many conversions are there?

Material: Analogue or PCM or PDM with various bitspeeds.

Input: what conversion to digital does various amps make?

DRC: How many and from/to what format do Audyssey, Dirac and others use?

Preamps: with volume a.o. what digital formats?

Poweramps: IF a digital amp, then a final conversion to PDM to feed the amp, otherwise a DAC to feed the amp.

How many conversions will that be?? And how much dist will that add?

Why are DRC-vendors so secretive about what format they use for their filtering?

HiFi would benefit from as few conversions as possible. How about a standard for internal use to be used by all? Like PCM 44.1kHz 16 bits for cheaper models and perhaps 192kHz 24 bits for topend. Same software just selected by the amp-producer to differentiate their productlines.

Especially important when several different DRC shows up in the same amp, like Denon, Marantz, Pioneer a.o. which can have both Audyssey and Dirac on the same amp.

What do YOU think?

My first tape recorder bought 1972, the fantastic Revox A77 HS 19/38cm/s two track is to be restored.

It had its magnetic heads replaced for “Revodur-heads” and some components replaced for low-noise by one of two Revox-wizards of Stockholm at that time “Max Weber”.

The machine worked well for a while but was then replaced by a more practical machine, actually a casette deck! The magical Nakamichi Dragon! A dream machine pushing the tiny but practical casette tape into almost the domain of Revox. By dynamic calibration of azimuth, double capstan, three heads, metal tape capabilities and Dolby C.

The Revox was put on hold, for many years. Just took it out of retirement now, only to find that it was not working properly, the treble was way to low and recording did not work well. Could well be electrolytes aging over the 50 years of age of my machine?

So a service visit is planned to the other Revox-wizard of Stockholm “Gerhart Schubert”!

We will see what comes out of that… I´ll be back… like hopefully my old Revox A77!

Waiting for it, will be some master tapes of Opus3 of my friend since way back then Jan-Erik Persson.

Old refined technology will meet modern DRC-electronics and my Klipsch Palladium speakers!