1000 Pro with SAM (Dynaudio Focus 360)

[Redwingnine]

After reading some other threads relating to SAM, looks like I'm in the minority.  I'm very happy with using SAM on the 1000 Pro with Dynaudio Focus 360 speakers.  I've tried various percentage settings with SAM, and in my listening environment, 50 to 70 percent settings improves the overall playback.  If anything, the Focus 360 sounds better with SAM ON vs. SAM OFF.  Even the 100% sounds better than SAM OFF, but 100% can be a bit much with some bass heavy recordings.

I'm also using a Chord M-Scaler for my sources, which makes a significant improvement in playback performance.  Would love to see future Expert Pro amps incorporate this functionality.  Makes me wonder if the M-Scaler is helping improve the SAM usage. 

What do you reckon?

[audio_engr]

I use 440-Pro and tried SAM for my speakers that I did not like. It just made the sound very un-natural and electronic hence for the last 3-4 years, have always preferred as SAM OFF. I do use a pair of subs with my 2-ch speakers therefore the combo of fullrange floorstanders + pair of subs together is just amazing without any additional electronic help from the Devialet. 

However, I have DPM set to OFF that I find improves reproduction esp. the dynamics.

[Redwingnine]

I use 440-Pro and tried SAM for my speakers that I did not like. It just made the sound very un-natural and electronic hence for the last 3-4 years, have always preferred as SAM OFF. I do use a pair of subs with my 2-ch speakers therefore the combo of fullrange floorstanders + pair of subs together is just amazing without any additional electronic help from the Devialet. 

However, I have DPM set to OFF that I find improves reproduction esp. the dynamics.

Interesting.  Perhaps SAM is speaker dependent as to performance?   A few years back, tried SAM with a pair of ATC SCM-19 V1, and did not care for it at all.  Worked just as you described. 

However, with the Dynaaudio 360's, the improvement is remarkable.  Sounds very natural.  In fact, it makes the playback sound more natural, not less.  Maybe SAM integrates better with larger three way floor standing speakers as opposed to monitors?  Since it only impacts below 200 Hz, could see where that would make some sense.  It would not impact the midrange driver of the three way, but would impact the monitor driver.

[David A]

I think SAM is both speaker dependent and room dependent, and, given that different people have different tastes when it comes to bass response, I think there's also an element of personal taste in whether the user is going to prefer it off or on and, if on, at what SAM setting.

Let's get the speaker dependent part out of the way first. SAM corrects the speaker's phase behaviour below 150 Hz. That changes bass output and SAM also includes speaker protection by limiting the bass driver's excursion. Take a look at the "specs" for SAM with different speakers on Devialet's site and you'll see that the quoted SAM response below the speaker's specified response varies considerably. I think that difference is due in part to just how much harder the speaker driver can be driven before reaching the point where SAM starts applying limiting in order to prevent excessive driver excursion.

Second, room dependency. There's a lot of unevenness in bass response in small rooms and our listening rooms are small rooms acoustically. If SAM's phase correction strengthens the speaker's bass response at a frequency where the room is producing a bass peak, then SAM is going to make that peak worse. I think Jim Austin of Stereophile described that sort of behaviour when he described his experience using SAM when he reviewed the Expert 140 Pro. He gave a very positive review but mentioned that using SAM seemed to cause a room problem with his speakers. In other words, it seems likely that using SAM with the same speakers in 2 different rooms may yield 2 different results.

Then there's the personal taste issue.

Here's a quick summary of my personal love/hate/love history with SAM.

I was using Dynaudio Contour 1.3 SE's when I got my 140 Pro (then a 130 Pro) back in 2017. I really liked the results I got with SAM at, if I remember correctly, a setting of around 50%.

I upgraded my speakers to Focal Sopra 2s and found I preferred SAM off because it produced a hardening of tone in the lower voice range but I also wasn't happy with the setup of the new speakers. After a long period of experimenting with speaker placement along with small changes in the position of the listening chair and also with the placement of the acoustic panels in my room, I finally got a setup where I prefer SAM on but at a setting of 0%. The Sopras load the room differently to the way the Contours did plus they extend a few Hz lower than the Contours did. I suspect I was initially running into a room response issue which was exacerbated by SAM and that it wasn't until I solved that problem that I was happy using SAM with the Sopras.

So I think there's quite a few factors which affect how different users find the use of SAM and even users with the same amp and speakers may find themselves having different experiences due to speaker/room interaction and personal taste.

[Delija]

I use 440-Pro and tried SAM for my speakers that I did not like. It just made the sound very un-natural and electronic hence for the last 3-4 years, have always preferred as SAM OFF. I do use a pair of subs with my 2-ch speakers therefore the combo of fullrange floorstanders + pair of subs together is just amazing without any additional electronic help from the Devialet. 

However, I have DPM set to OFF that I find improves reproduction esp. the dynamics.

Interesting.  Perhaps SAM is speaker dependent as to performance?   A few years back, tried SAM with a pair of ATC SCM-19 V1, and did not care for it at all.  Worked just as you described. 

However, with the Dynaaudio 360's, the improvement is remarkable.  Sounds very natural.  In fact, it makes the playback sound more natural, not less.  Maybe SAM integrates better with larger three way floor standing speakers as opposed to monitors?  Since it only impacts below 200 Hz, could see where that would make some sense.  It would not impact the midrange driver of the three way, but would impact the monitor driver.

Nope. It's not the size / type of the speakers. I had Contour 60's. The higher the class of the system - the easier to hear the DSP "artifacts".

[Redwingnine]

I use 440-Pro and tried SAM for my speakers that I did not like. It just made the sound very un-natural and electronic hence for the last 3-4 years, have always preferred as SAM OFF. I do use a pair of subs with my 2-ch speakers therefore the combo of fullrange floorstanders + pair of subs together is just amazing without any additional electronic help from the Devialet. 

However, I have DPM set to OFF that I find improves reproduction esp. the dynamics.

Interesting.  Perhaps SAM is speaker dependent as to performance?   A few years back, tried SAM with a pair of ATC SCM-19 V1, and did not care for it at all.  Worked just as you described. 

However, with the Dynaaudio 360's, the improvement is remarkable.  Sounds very natural.  In fact, it makes the playback sound more natural, not less.  Maybe SAM integrates better with larger three way floor standing speakers as opposed to monitors?  Since it only impacts below 200 Hz, could see where that would make some sense.  It would not impact the midrange driver of the three way, but would impact the monitor driver.

Nope. It's not the size / type of the speakers. I had Contour 60's. The higher the class of the system - the easier to hear the DSP "artifacts".

Not entirely sure I buy this.  The entire Devialet architecture is a computer based design.   The few reviews I've read that demurred about Devialet sound quality complained the entire sonic signature sounds like a digital artifact.  I certainly don't agree with that.  

The SVS subwoofers also use DSP to shape the filtering.  Do you also hear artifacts with that?   I don't hear any artifacts with the PC4000.  

Since SAM only deals with frequencies at or below 150 Hz, that is a smaller subset of musical instruments.  Most likely to impact the very lowest register of piano, bass, and cello primarily.  Can't say that I've noticed a significant amount of digital artifacts with SAM on.  I actually notice less digital artifacts with SAM than I do when listening to the Devialet without the Chord M-Scaler in the loop as a front end processor.  The M-Scaler actually is more noticeable in reducing (time domain) digital artifacts than any perceived artifacts generated from SAM.

[Delija]

It's not that simple...

Dive a little into digital signal processing topic and you'll very quickly realize that's impossible to affect just one part of the frequency range. If you "touch" 50 Hz - you are affecting the whole frequency range. Unfortunately, you can't beat the mathematics - that is true even for the simplest DSP effects like high-pass filter.

Yes, SVS uses DSP - but that is limited only to the lowest frequencies where these artifacts are (almost) inaudible and irrelevant - and it's not affecting the full frequency range / stereo signal which is on completely different signal path. Still, for any e.g. PEQ adjustment on SVS near the crossover frequency you also need to adept the phase - because its filters introduce a phase shift. And the phase is just one part of the story. There are different kind of filters - some of them don't even affect phase, but have other problems / limitations - like pre-ringing.
https://www.dsprelated.com/freebooks/fil...Phase.html

If you are interested in digital signal processing, you can start with this book - i'ts a little older, but still very good.
https://www.google.com/url?sa=t&source=w...KInGTRwl8S

[Redwingnine]

It's not that simple...

Dive a little into digital signal processing topic and you'll very quickly realize that's impossible to affect just one part of the frequency range. If you "touch" 50 Hz - you are affecting the whole frequency range. Unfortunately, you can't beat the mathematics - that is true even for the simplest DSP effects like high-pass filter.

Yes, SVS uses DSP - but that is limited only to the lowest frequencies where these artifacts are (almost) inaudible and irrelevant - and it's not affecting the full frequency range / stereo signal which is on completely different signal path. Still, for any e.g. PEQ adjustment on SVS near the crossover frequency you also need to adept the phase - because its filters introduce a phase shift. And the phase is just one part of the story. There are different kind of filters - some of them don't even affect phase, but have other problems / limitations - like pre-ringing.
https://www.dsprelated.com/freebooks/fil...Phase.html

If you are interested in digital signal processing, you can start with this book - i'ts a little older, but still very good.
https://www.google.com/url?sa=t&source=w...KInGTRwl8S

Thanks for the references.  I'll certainly read up on them.  I'm quite interested in this topic. 

Regarding the SVS subs, they DO provide a high pass filter to power amps, so anyone using that setup as an input to a power amp would impact the overall playback, would it not?  

As I understand SAM, it's primary objective is to correct the phase alignment of a given speaker configuration at and below 150 Hz.  It also is supposed to modify the signal such that it remains a flat frequency response as low as the speaker design will go without damaging the driver(s).   The argument is that it is impacting the rest of the frequency response, causing digital artifacts.  Is that the crux of your point?

Digital audio, IMHO, is all about filtering/processing to begin with.  Off the shelf filtering solutions all have limitations.  Didn't realize just how much of an issue this is until I got into headphones.  Once I heard a Chord M-Scaler and Hugo TT2 DAC, this issue really hit home.  The Chord gear addresses time domain issues with digital audio quite well.  Hook up a Chord M-Scaler to a Devialet and one immediately hears a difference. If anything, the M-Scaler addresses a host of limitations with digital playback.  The Devialet playback definitely improves with the M-Scaler in the chain. 

I'm trying to understand what digital artifacts actually means.  The primary difference I notice is that the sound is thinner overall with SAM OFF.  If anything, dynamics are slightly less overall with SAM OFF.   I don't remember Jim Austin complaining about digital artifacts in his review of the 140 Pro.  He did complain about too much bass.  It does make one wonder if a lot of recordings are mixed with extra LF energy.

[Delija]

Newer SVS subs don't have high-pass filter. Older ones did - and it was very poor quality.

"Artifacts" = bad effects of processing on transparency, resolution, dynamics, timbre, imaging, soundstage, "air"...

In high quality systems, with high quality speakers and components, where speakers are properly positioned, in rooms which are acoustically treated, with subwoofers that are optimized on their own - DSPs have more negative effects on the sound than positive.

I played a lot with different solutions for high-pass filter - digital and analog. Devialet Expert is pretty good, but not 100% transparent. The same is with JL Audio CR-1 - the analog filter. In the end - I gave up from high pass filter for stereo / hi-fi usage. Only subwoofers are being EQed.

[Delija]

SAM can be useful for some smaller / bookshelf speakers to make them play as somewhat larger speakers with deeper FR, but only if not played too loud - it will "eat" their headroom very quickly. For such speakers benefits of SAM could be greater than the drawbacks. Even with larger speakers SAM can and usualy does improve bass, but (for me) the cost is too high. If you ask me - subwoofers are much better solution.

BTW,, everyone can decide for himself what he likes better. A lot of people listen to systems with Dirac and similar room correction DSPs turned on. It's beyond me how they don't hear how bad effect it has on the sound - it steals the soul of the music . The good sound is so much more than the linear / flat FR.