"hacking" SAM to do convolution

[David A]

SAM basically covers the frequency range from 200 Hz on down. That's the bottom 3 and a half octaves of the 20 - 20,000 Hz range we regard as audible, roughly one third of the range. I don't know how many adjustments within that range the hardware that implements SAM is capable of handling but if you want to do room correction you want to cover the whole 20 - 20000 Hz range. That's going to require a lot more adjustments to do well than covering the range from 200 Hz on down.

The processor which applies SAM corrections may be capable of doing convolution processing but does it have enough power to do the amount of processing required to make an improvement over 10 octaves rather than the 3.5 octaves required for SAM? You probably aren't going to get by with any fewer adjustments from 200 Hz on down in a full range room correction filter than you do with a SAM profile so if you hack the SAM processing code you're going to ask it to handle the corrections for the current 3.5 octave range it is intended to handle plus the corrections for another 6.5 octaves.

I'd want to know a lot more about how SAM is implemented, how much of the processing power in a Devialet is devoted to that processing, and whether it's a separate processor or just a routine in the overall processing code.

Like everyone here I think being able to implement room correction in the Devialet would be of great benefit but I don't think hacking the code for processing SAM sounds like a good way to go about it. I think room correction is going to take more processing muscle than is used for processing SAM profiles and if you can hack the SAM code and access enough processing power to do what you want you may well be taking processing power away from other essential functions which might actually make your results worse rather than better.

[whatmore]

SAM basically covers the frequency range from 200 Hz on down. That's the bottom 3 and a half octaves of the 20 - 20,000 Hz range we regard as audible, roughly one third of the range. I don't know how many adjustments within that range the hardware that implements SAM is capable of handling but if you want to do room correction you want to cover the whole 20 - 20000 Hz range. That's going to require a lot more adjustments to do well than covering the range from 200 Hz on down.

The processor which applies SAM corrections may be capable of doing convolution processing but does it have enough power to do the amount of processing required to make an improvement over 10 octaves rather than the 3.5 octaves required for SAM? You probably aren't going to get by with any fewer adjustments from 200 Hz on down in a full range room correction filter than you do with a SAM profile so if you hack the SAM processing code you're going to ask it to handle the corrections for the current 3.5 octave range it is intended to handle plus the corrections for another 6.5 octaves.

I'd want to know a lot more about how SAM is implemented, how much of the processing power in a Devialet is devoted to that processing, and whether it's a separate processor or just a routine in the overall processing code.

Like everyone here I think being able to implement room correction in the Devialet would be of great benefit but I don't think hacking the code for processing SAM sounds like a good way to go about it. I think room correction is going to take more processing muscle than is used for processing SAM profiles and if you can hack the SAM code and access enough processing power to do what you want you may well be taking processing power away from other essential functions which might actually make your results worse rather than better.

Good points

If I look at the config file, there seem to be 128 SAM points but I don't know what they mean

Regarding only covering the bottom octaves, there is an argument that this is all you should do anyway. So I'd take that as an interim step. It's better than nothing

[baddog]

A proper convolver in the Expert amplifier would be perfect.

Yes, exactly.

Many have waited for this feature for years, but it doesn't even seem to be on their roadmap. What are they thinking  

Maybe they will release their own digital room correction feature at some point in the future? I truly hope that they would release at least some kind of solution to this problem.

With all due respect, looking at this through the lens of Devialet, what percent of customers do you think are looking for such a solution?

My (WAG) guess is less than 1% of their installed customer base. I don't foresee the majority of customers using this feature, IMHO, YMMV.

p.s. I want to be clear that I am not saying this to be argumentative, nor negating the fact that many users do wish for this capability.

[whatmore]

With all due respect, looking at this through the lens of Devialet, what percent of customers do you think are looking for such a solution?

My (WAG) guess is less than 1% of their installed customer base. I don't foresee the majority of customers using this feature, IMHO, YMMV.

p.s. I want to be clear that I am not saying this to be argumentative, nor negating the fact that many users do wish for this capability.

You make a good point. I guess what I was hoping was that it wouldn't be too hard for them to implement for the admittedly small number of users who do want it.

Having said that, I wonder how many users were looking for SAM before it was introduced?
The demand is there because they created it.

[petrik]

A proper convolver in the Expert amplifier would be perfect.

Yes, exactly.

Many have waited for this feature for years, but it doesn't even seem to be on their roadmap. What are they thinking  

Maybe they will release their own digital room correction feature at some point in the future? I truly hope that they would release at least some kind of solution to this problem.

With all due respect, looking at this through the lens of Devialet, what percent of customers do you think are looking for such a solution?

My (WAG) guess is less than 1% of their installed customer base. I don't foresee the majority of customers using this feature, IMHO, YMMV.

p.s. I want to be clear that I am not saying this to be argumentative, nor negating the fact that many users do wish for this capability.

Unfortunately I don't have any facts to answer to your questions. Reality can be anything between 0 and 100 %.

I believe that many (=something between 0 and 100 %) should be at least interested in this topic because many don't have perfect room acoustics, perfect loudspeakers, perfect location of the loudspeakers in their listening room and perfect location of the sweet spot(s). Digital room correction doesn't of course fix all of the problems, but it can help a lot when done properly.

I also believe that you are absolutely correct that this may not be a priority feature for Devialet. Their vision is basically that "someday everyone owns a Devialet" and logically thinking that would mean doing the mainstream features first (like for example Spotify streaming support). As we can see from the Core Infinity features, it's all about adding mainstream streaming features to the Expert product line. Nothing about more advanced features. The question that I'm thinking is that how well does these mainstream features fit to the Expert product line.

We can also see a trend that many companies have already implemented some kind of an integrated solution to the room correction (Linn, Lyngdorf, Trinnov, Genelec, Sonos, Avantgarde, Martin Logan, most of the subwoofers and AV-receivers, just to name a few). Point is that the integrated room correction is already a popular mainstream feature. So perhaps there is a hope that someday Devialet also implements this feature. 

[Rodney Gold]

A simple 4-5 band parametric could possibly be integrated rather than their rather sucky tone controls
If you want real room correction , buy a trinnov...

[petrik]

A simple 4-5 band parametric could possibly be integrated rather than their rather sucky tone controls
If you want real room correction , buy a trinnov...

Parametric eq would be a great starting point to a right direction.

Why Devialet couldn't or shouldn't make a "real room correction"? They certainly should have all resources and capabilities to do it well.

Moreover, I have got a feeling that Devialet employees don't like the idea of using external DSP. Every time when I discuss with them, their first recommendation is to disable all external DSP and let Devialet handle it all. I would love to follow their guidelines, but their DSP is completely missing some of the features that I need...

[ogs]

@David A :"I'd want to know a lot more about how SAM is implemented, how much of the processing power in a Devialet is devoted to that processing, and whether it's a separate processor or just a routine in the overall processing code."

In the past Devialet has indicated that there is unused DSP capacity in Experts that can be used for convolution. Maybe SAM processing uses most of this so there is little capacity left. In the main DSP that is... With the CI additional CPU power is added so convolution should be possible. I think it is more of a 'popularity' thing and the 'Not Invented Here' syndrome. What three letter acronym should Devialet use for the unique feature of Devialet convolution?

Here is a quote form Manuel de la Fuente in 2011: "Regarding speaker or room correction options in the DSP, we finally decided not to include it in this version of the configurator, both because we needed more time and because it is risky option to put in everybody's hands."
Yes it is risky. An increase in support cases - user: "my Devialet sounds terrible!" Devialet: "are you using convolution?" user: "yes and when I turn it off it sounds even worse!"..

[Hifi_swlon]

Wow they were properly considering it in 2010. How disappointing/depressing.....

A volume control’s risky in the wrong hands....

[maxijazz]

Devialet CON is the name.