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SAM effects
#41
The look of the bass trace, both phase shift and amplitude errors is influenced by many things, not just the size of the cone (or cabinet).
More efficient small speakers like the Cremona M will have had to sacrifice bass for the added sensitivity. Without DSP correction small, efficient and bass don't go together...
Devialet Original d'Atelier 44 Core, Job Pre/225, Goldmund PH2, Goldmund Reference/T3f /Ortofon A90, Goldmund Mimesis 36+ & Chord Blu, iMac/Air, Lynx Theta, Tune Audio Anima, Goldmund Epilog 1&2, REL Studio. Dialog, Silver Phantoms, Branch stands, copper cables (mainly).
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#42
It was actually the Focals I was surprised by, though I take your point about other factors than cone size being relevant. The claimed sensitivity of the two speakers: Focals 89dB; Sonus fabers 88dB.

Sonos Connect (W4S) > DSpeaker Antimode 2.0 > Sanders Magtech > Martin Logan Montis
Sonos Connect (W4S) > Devialet 200 > Vivid V1.5
Silver Phantoms (just the two)
London
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#43
(06-Mar-2015, 12:52)Jwg1749 Wrote: It was actually the Focals I was surprised by, though I take your point about other factors than cone size being relevant. The claimed sensitivity of the two speakers: Focals 89dB; Sonus fabers 88dB.

Oops I was comparing to the LS50.
Devialet Original d'Atelier 44 Core, Job Pre/225, Goldmund PH2, Goldmund Reference/T3f /Ortofon A90, Goldmund Mimesis 36+ & Chord Blu, iMac/Air, Lynx Theta, Tune Audio Anima, Goldmund Epilog 1&2, REL Studio. Dialog, Silver Phantoms, Branch stands, copper cables (mainly).
Oxfordshire

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#44
Frank, do you (or does anyone else) know how the speaker protection in SAM actually works? The point that I find hard to understand is how SAM can measure cone excursion "in real time" (as it claims on the SAM pages). That's to say, how can the DSP in the amp know how far the cone is moving without physically measuring it (which Devialet can do in their labs but is impossible "in real time")?
I could understand if SAM worked predictively, i.e. based on the lab measurements, SAM would be able to predict what SPLs were likely to generate excessive cone excursion and would limit power accordingly. But that's not really "in real time", is it?
Not sure if I've expressed myself clearly.
Matt

Sonos Connect (W4S) > DSpeaker Antimode 2.0 > Sanders Magtech > Martin Logan Montis
Sonos Connect (W4S) > Devialet 200 > Vivid V1.5
Silver Phantoms (just the two)
London
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#45
In crude terms, the lab measurements establish a model of the speakers performance. This virtual model is then reversed to make the SAM corrections. So SAM knows that if it puts x amount of power (volts x amps) into a speaker, this will result in x amount of cone movement, and x amount of heat into the voice coils. So if you think of SAM as being a virtual / digital model of the speaker, then yes, the Delialet's little brain can handle all this in real time. All very clever stuff! Obviously SAM is not taking any actual measurements, so if there is a difference between the actual speaker they had in the lab, and the one you have in your home, then this could be problematic! I presume that they have built in a reasonable safety margin to allow for production variations of a mass produced speaker? Or at least I hope they have!
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#46
What you describe above is what I was getting at when I said SAM worked "predictively", i.e. based on the speaker modelling in the labs, SAM predicts the cone excursion. To me that's not what "in real time" means, but perhaps I'm just being a bit pedantic about the phrase "in real time".

Sonos Connect (W4S) > DSpeaker Antimode 2.0 > Sanders Magtech > Martin Logan Montis
Sonos Connect (W4S) > Devialet 200 > Vivid V1.5
Silver Phantoms (just the two)
London
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#47
(08-Mar-2015, 12:54)Jwg1749 Wrote: What you describe above is what I was getting at when I said SAM worked "predictively", i.e. based on the speaker modelling in the labs, SAM predicts the cone excursion. To me that's not what "in real time" means, but perhaps I'm just being a bit pedantic about the phrase "in real time".

I guess SAM is working predictively in real time?  Plus in my book, there is absolutely nothing wrong with being pedantic! 
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#48
The following was posted on the Linn Forums site by a Linn engineer, by way of an explanation as to how SAM works and contrasting it to the Linn Exakt system:


"The Devialet SAM system functions as a bass extension filter. They match a shelving filter that is equal and opposite to the natural roll-on of the speaker(*), effectively pushing the low frequency response of the speaker down in frequency. The shelving filter will produce an equal and opposite phase response to the natural roll-on of the speaker(*) thereby linearising the low frequency phase response (to some degree).


(*) based on measurement of a single loudspeaker, so not truly accurate when you consider production variance.

At very low playback levels this extension can be pushed to (conceivably) quite low frequencies without end stopping the drive unit. However, as playback level is increased, the influence of the shelving filter applied by Devialet is reduced giving progressively less bass extension as the volume is increased. To claim that the low frequency of the Ninka is extended to 15 Hz is therefore rather disingenuous.

The Exakt filter for the Ninka does feature a bass extension filter as did our analogue Aktiv design, though the Exakt version is a rather better implementation. Unlike the Devialet approach the Exakt extension filter does not vary with the volume setting, so gives the same extension irrespective of playback level. As I recall it pushes the -3dB point down by about an octave from the natural response of the system (~35 Hz). Below this the speaker rolls-off with a 2nd order characteristic, so will be ~12 dB down at 17 Hz.

Having heard what the Devialet does to an Akurate 242 I am quite happy to state that the Exakt Ninka sounds significantly better then a passive Ninka driven by a Devialet amp."


Guillaume
Industry disclosure: UK distributor for Shunyata Research

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#49
(08-Mar-2015, 12:31)Jwg1749 Wrote: Frank, do you (or does anyone else) know how the speaker protection in SAM actually works? The point that I find hard to understand is how SAM can measure cone excursion "in real time" (as it claims on the SAM pages). That's to say, how can the DSP in the amp know how far the cone is moving without physically measuring it (which Devialet can do in their labs but is impossible "in real time")?
I could understand if SAM worked predictively, i.e. based on the lab measurements, SAM would be able to predict what SPLs were likely to generate excessive cone excursion and would limit power accordingly. But that's not really "in real time", is it?
Not sure if I've expressed myself clearly.
Matt

Matt,

I now have some 400 hours on my Raidho X1. I've been raving about these and chose them over Raidho D1. Now with some hours down the line, with SAM of course, I have a few comments. SAM works, for sure, bringing better coherence to the whole freq spectrum. Added octave down in the bass region. Now it comes: The protection works, and that is great in avoiding any problems with overpowering. BUT, for me in my home and with 400 W in each channel playing orchestra levels of sound pressure, for sure bass get less with increased volume, good but really bad when it comes to classical full orchestra volume. If I take down the volume bass is there again. These are wonderful speakers but I already started to look at replacements because of this limitation. Low lever listening gives some really full sound down to 25 Hz, but when these speakers are called for some output, SAM cool everything down. Disabling SAM does not help as without one octave is lost and the coherence for the rest is lost. 
The fact that these speaker probably are about 80 dB/1W this does not help on the output side (some magazine tester reported 80 dB/1W for the C1.1 model).
I notice clear how SAM goes in and protect/Mike

I thought my hunt for loudspeakers was over but I guess it will begin again.
Ex D400 Now Aavik U-300/Feickert Woodpecker2-Kuzma 4P-Kondo silver-Benz LPS-Teddy Pardo PSU/Naim Unitiserve-Teddy Pardo PSU/SF Guarneri Homage/Whole system decoupled by Ansuz DTC/Cables from Ansuz, DYI and other commercial/Dedicated mains and spur-Lampizator SILK
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#50
(08-Mar-2015, 14:08)GuillaumeB Wrote: The following was posted on the Linn Forums site by a Linn engineer, by way of an explanation as to how SAM works and contrasting it to the Linn Exakt system:


"The Devialet SAM system functions as a bass extension filter. They match a shelving filter that is equal and opposite to the natural roll-on of the speaker(*), effectively pushing the low frequency response of the speaker down in frequency. The shelving filter will produce an equal and opposite phase response to the natural roll-on of the speaker(*) thereby linearising the low frequency phase response (to some degree).


(*) based on measurement of a single loudspeaker, so not truly accurate when you consider production variance.

At very low playback levels this extension can be pushed to (conceivably) quite low frequencies without end stopping the drive unit. However, as playback level is increased, the influence of the shelving filter applied by Devialet is reduced giving progressively less bass extension as the volume is increased. To claim that the low frequency of the Ninka is extended to 15 Hz is therefore rather disingenuous.

The Exakt filter for the Ninka does feature a bass extension filter as did our analogue Aktiv design, though the Exakt version is a rather better implementation. Unlike the Devialet approach the Exakt extension filter does not vary with the volume setting, so gives the same extension irrespective of playback level. As I recall it pushes the -3dB point down by about an octave from the natural response of the system (~35 Hz). Below this the speaker rolls-off with a 2nd order characteristic, so will be ~12 dB down at 17 Hz.

Having heard what the Devialet does to an Akurate 242 I am quite happy to state that the Exakt Ninka sounds significantly better then a passive Ninka driven by a Devialet amp."


Guillaume

Sounds like one implementation protects the drivers at louder volumes and the other doesn't.  Fortunately I have efficient speakers and my ears don't let me listen at louder volumes any more.
Roon->HQPlayer->McIntosh C47->McIntosh MC301s>Transparent Super->Wilson Audio Sabrinas w/ Shunyata Denali, Rega RP8, Rega Apheta 2


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