Music as it should sound with SAM
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TEST CORRECTION-SOFTWARE
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Music as it should sound
with SAM
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With its new "SAM" software, Devialet hopes to correct anomalies with our speakers. A
great idea - but "Speaker Active Matching" actually offers much more
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The Devialet hype continues! In 2011, the French newcomer stunned experts with its
technically and optically radical "D-Premier", whose ADH concept - which stands for "Analogue
Digital Hybrid" combined a low-distortion class-A amplifier with an equally powerful and
efficient switching output stage. Last year, the Paris-based manufacturer went on the offensive
with a whole series of new amplifiers that are based on this revolutionary technology.
The exclusively digital signal processing relies on powerful processors that allow the
owner to configure the device according to their individual requirements. The menu includes an
extensive range of options, from assigning the inputs to the standby brightness of the display,
which can even be used to view the operating temperatures of the A and D amplifier and the
switched-mode power supply. Pure high tech!
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Correction via download
Devialet amplifiers feature software support and are therefore open platforms on which
modifications can be made. This recently enabled owners to enhance performance via a quick
update on the well-organised website. The entry-level 110 amplifier - the number indicates the
continuous output power per canal into six ohms - became the 120, and the 170 became the 200.
All for free!
In addition, the team lead by mastermind Pierre-Emmanuel Calmel (see interview on
page 18) has introduced software specific to each model that is designed to counteract
anomalies. "Speaker Active Matching" (SAM) can access a database of 200 speaker models and
is especially designed
to address time delays for frequencies under 200 Hz. Almost every multi-way speaker system
produces time delays, as the heavy bass membrane reacts more slowly to amplifier signals than
the lightweight tweeter. Mechanical and technical measures are employed to minimise time
delays, which come at the expense of homogeneity and the spatial quality of the sound. With
SAM, Devialet is now promising digital optimisation with maximum precision.
14 STEREO 10/2014
Source Speaker Reproduced
Signal Signal
Volume
Loudspeaker control Class A
Model voltage
amplifier
DAC A
Sense Class D
current
Loudspeaker amplifer
Parameters
CTRL D
Desired Computed amplifier Air
air pressure output voltage pressure
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The "Speaker Active Matching" takes place digitally before the D/A-conversion and is linked to the volume
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Anyone who owns a Devialet and one of the approximately 40 SAM-ready speakers can
simply download the correction data from the website and save it onto the SD card that contains
the "operating system" for each amplifier in order to be able to listen to improved-quality sound.
All for free!
Downloading is straightforward. During our test we reconfigured our 120 many times - all
without the slightest of problems. During our investigations we found that SAM is much more
than just a static tool to counteract time delays and frequency response errors in the bass -
which would in itself be no mean feat. It would be much better described as a complex system
that reacts dynamically to different operating conditions and that can optimally control the
speaker in all sorts of situations and acoustic environments.
You can click on "Configurator" at www.devialet.com , where the "Advanced" mode offers SAM correction curves
for a growing number of speakers.
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STEREO 10/2014
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Before we were aware of all of its features, we tried SAM out for ourselves on two B&W speaker
models. We began with the CM10 floorstanding speaker that was released last year (approx. 3600
Euros/pair), which is one of the most popular models in its category. You can also determine
which button on the remote control turns SAM on and off via download. You can sit in your chair
and switch seamlessly between the different modes. It couldn't be easier!
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Improvements into the mid-ranges
We connected the CM10 and then the compact 805 Diamond (approx 4500 Euros/pair) using an
HMS bi-wiring cable (i.e. without metal bridges) in order to exclude other influences. Then we
were ready to begin. What struck us first was that the CM10 - which already boasts a strong bass
- produced more full-bodied, robust nuances and the bass had a deeper range. It soon became
apparent that it was the quality rather than quantity of the lower levels that led to this
impression. The dark timbre of the percussion in Amber Rubarth's "Good Mystery" gained in
intensity and strength, and the guitars in the intro of "Marie-Jeanne-Gabrielle" sounded more
energetic and full-bodied when SAM was activated; Louis Capart's voice was given a small extra
boost of vibrancy.
This is because the changes that SAM makes extend right into mid-ranges. It is the time-
delay correction - which works right into the bass range and provides tonal "support" - that is
mainly responsible for these changes. This is even true when there is no obvious bass present. In
the choral piece "Mitt Hjerte Alltid Vanker", as in the other tracks on the STEREO audio test CD
VII, the choir sounded more colourful, smooth and balanced with SAM. Devialet's correction is
anything but a simple bass control - it is first and foremost a tool for producing audiophile
virtues.
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Fed with the correction data
for B&W's compact 805
Diamond (see left), our
measurements clearly
demonstrate the dynamic
function of the SAM software
at the amplifier output of
the 120. With the time
correction, this has a
relatively strong impact
below 50 Hz and significantly
enhances the deep bass
where the compact speaker
has to increasingly adapt.
However, this only happens
at low volumes that do not
pose any problems to the
s p e a k e r. T h e c u r v e s -
obtained at different levels -
show that the rise is increasingly smaller as the power increases, until there is a decrease when the 50 W
line is reached, which the chassis would reach quickly in linear operation. SAM therefore protects the
woofer against overload and enables the listener to listen at volumes louder than would be possible
without correction. One of the most sought-after high-end speakers is B&W's CM10. It sounds more potent
and controlled with SAM.
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STEREO 10/2014
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We then changed to the 805 Diamond. This involved turning off the amplifier, removing
the SD card, downloading the data for the new speaker on a PC, inserting the SD card and
turning on the amplifier - then we were ready. This took us two minutes. Overall, the outcome
was the same for the compact speaker as for the floorstanding model we tested previously, but
the increase in strength and bass potency was more obvious here. In the results of our test, the
smallest B&W Diamond came out at least half a class better in terms of maturity and
expressiveness.
However, the differences between the two speaker models remained clear. SAM does not
dramatically change the speaker and its original tuning, but rather complements the sound with
important nuances in a way that would not otherwise be possible.
What we didn't learn until later in the laboratory: SAM constantly takes the volume into
account. Using its data, the system is aware of the capabilities and limits of the connected
speaker and can take these into consideration during the correction process. For example,
compact models such as the 805 Diamond are limited in the bass. SAM can therefore help here.
However, this is only the case at low to middle volume levels, as otherwise the risk of overload
or damaging the woofer membrane quickly develops. SAM therefore reduces the bass
accentuation as the volume rises and even reduces bass tones after a certain level to minimise
distortion and protect the speaker.
The listener does not notice anything. The changes are smooth are subtle. We carried out
frequency response measurements on the speakers, but the visible changes under 200 Hz were
so small that we decided not to include a graph and focus instead on reporting our
measurements on the amplifier output. However, the influence of SAM was audible with the test
sweep.
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Adjusts to different setups
As if that were not enough, SAM can be controlled precisely using a corresponding function. This
primarily affects the frequency response. For example, if the speaker is placed near to a wall,
the combination of energy and richness that results from the time and bass correction may
sound too dominant. Users should be able to find a setting between 0 and 100 percent for most
setup arrangements. For those who want even more control, the Devialets also feature normal
tone controls, which we did not use.
Our tests will reassure anyone who is concerned that SAM may undermine the character
of the speaker. Devialet’s goal is not to use SAM to make everything sound identical, but rather
to fix specific, low-frequency anomalies and enhance rendering. During the course of our tests
every speaker retained its typical features. Making a Wilson Audio Sophia 3 out of a B&W CM10 is
something that SAM neither can nor is designed to do. Apart from that, this ingenious, extremely
sophisticated free software made by speaker technology experts is a real asset and strong reason
for purchasing a Devialet. And for anyone who is still apprehensive about SAM: it can be turned
off at the touch of a button. Matthias Böde
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STEREO 10/2014The low bass is also enhanced under
40 Hz for Wilson Audio's Sophia 3
(see box on left). It can also be
observed that the bass curve
becomes flatter with increasing
power. At 50 W a decrease occurs,
but only really in the lowest register,
as the Sophia 3 is of course
significantly stronger and more
powerful than B&W's 805 Diamond.
The bottom graph shows the
frequency corrections for a 2 W
power output when the effect of
SAM is reduced manually (see
display).At 25 percent, virtually no
bass enhancement is observed. The
time-delay correction remains
unaffected.
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Comment from Matthias Böde, Rédacteur Stereo
There has been much discussion about the tonal characteristics of Devialet's innovative ADH
concept, especially since the arrival of their new models.
STEREO has been getting involved, and has not only rigorously tested the 120 - which at the
time was still the 110 - but has also held a workshop on the theme, where the 110 was put
to the test against a classically built transistor and a tube amplifier. One could argue over
the results, but Devialet is now in a class of its own - none of their competitors have been
able to tackle speaker issues so proactively.
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STEREO 10/2014! ! How does SAM perform in a hi-fi studio? ! Our results from the editorial team are conclusive. But we wanted to acquire more experience of using SAM with other speakers. However, dragging along two 80-kilo speakers such as Wilson Audio's outstanding Sophia 3 in sultry 30-degree heat is no fun. Luckily, we found a pair near us at Klangpunkt in Aachen, and HiFi Eins in Cologne had Sonus Faber's Venere 2.5 on display. Correction curves are available for these models, and both dealers stock Devialet products. We therefore took the opportunity to test SAM in the typical conditions of a hi-fi studio. Klangpunkt had painstakingly assembled the Sophia 3 ready for our visit. We used the Devialet 200 as the driver. At 19,800 Euros a pair, the Wilson is in a completely different price category to a model such as the B&W CM10. Nevertheless, the improvements made by SAM - we were aiming for 100 percent - were evident straight away. We used a McIntosh player to play and then output digitally the easy-listening disc "Fourplay" with Bob James and Earl Klugh. ! The distinctive bass did not sound any louder when SAM was activated, rather more intense and rougher, making it easier to follow. Without the correction the bass was somewhat lacking in punch. We then changed to the STEREO audio test CD VII. In Liza Minelli's "Old friend", SAM gave more colour and "body" to an otherwise overly guttural, somewhat hollow voice. The wind instruments also sounded more pleasant and the very deep bass underneath the noise of the rousing live performance could only be heard properly when correction was activated. In Amber Rubarth's "Good Mystery", the muffled sound of the drums improved and the voices and guitars in "Rainbow's Gold" by the trio "The Greater Good" acquired more body and vibrancy. Overall, the recording sounded more expressive thanks to SAM, and the changes were very similar to those on a CM10, albeit generally not as obvious. The Sophia 3 therefore offers better out-of-the-box performance. ! The real surprise came at our session at HiFi Eins. None of our other test speakers benefited so considerably from SAM as Sonus Faber's Venere 2.5 (approx. 2800 Euros/pair). As in the editorial team's test, a Devialet 120 was connected, which matched perfectly with the Venere. However, when we activated the correction software, the recording sounded better on all counts - it sounded noticeably catchier and more concentrated - as if we had just tightened some loose reins in the lower levels. The improvement to the bass lasted throughout the track. ! This was very evident in "Attempo" by the Antonio Forcione Quartet - this time played on a player manufactured by Moon - it almost appeared to sound faster with SAM due to the dynamics being spot on. Without correction, the recording sounded slightly bloated and protracted. In addition, we also noticed more openness and transparency in the mid-range. This remained the case when we reduced SAM. We will later confirm in the laboratory that the attenuator for the Venere 2.5 was disabled by Devialet – not a problem, because Sonus Faber is able to make full use of SAM's potential. ! ! ! ! ! ! ! STEREO 10/2014
! ! You can vote for different loudspeakers on Devialet's website. The models that gain the most votes will be given priority during the often very time-consuming preparation of correction curves. The screenshot only shows a small selection of the types that are already available. ! ! ! ! "A Devialet must always stay up to date" ! ! |STEREO: Monsieur Calmel, how are the correction curves for individual speaker models calculated? Calmel: They are basically calculated using the latest measuring technology - a Klippel system is used to obtain all the relevant parameters, which we then feed into our algorithms. Two engineers have been working exclusively with loudspeaker measurements for some time. The time required depends considerably on the type of speaker concerned. A two-way speaker that transmits its bass/mid-range at up to about two or three KHz can be completed relatively quickly. Three-way systems are more complex as the crossover frequency from the low to middle range is normally between 100 and 200 Hz - i.e. exactly in the range that SAM corrects. The more chassis that are graded in the frequency range, the more complicated the task. Collecting all the necessary data for a B&W CM10 can take a whole day. ! |Do you carry out any other tests? Oh yes! With more complex speakers we normally measure the crossovers and the chassis inside and outside the housing, then include these results with others such as the measurements of the speaker housing and bass reflex port openings. Quite a substantial task. Fortunately there are many manufacturers and distributors that support us with data such as the effective mass of their speaker cones or details on the crossovers. ! |Do you verify the results by listening to the product? STEREO 10/2014
As our measuring lab is located in the basement directly below our Paris showroom, we only
have to travel a very short distance and can test the SAM correction in practice straight away.
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I So it's about more than just group delay?
Yes, our goal is comprehensive optimization of the frequency range under 200 Hz, where 90
percent of speaker anomalies can be found. Enhancement is therefore most beneficial in this
area. This involves the frequency response. As we cannot correct down to 1 Hz, we cut off the
lowest levels depending on the capabilities of the speaker, which can be done easily with digital
technology.
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| The data bank should ultimately cover 200 speakers. How do you make your choice?
Hi-fi fans can choose their favourite models on the website. We will then work on the models in
this order – effectively guaranteeing that the most widely used models will be included first. The
idea has been very well received. Perhaps too well, as we have already seen cases of people
trying to vote hundreds of times for their speaker or ask their friends to help them vote. We now
want to prevent this by requiring people to give their address.
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I And what about listeners with older speakers?
Let us know! We are currently measuring a model by Elac that is no longer produced and for
which there was a high demand. We went to pick up the model from a German audiophile who
voted for it. The customer got a rental speaker from us so that they can continue to listen while
we carry out the tests.
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| Devialet has surprised hi-fi fans with its recent improved performance and SAM. What's
coming next?
We are currently making the USB interface on our amplifiers bi-directional so that listeners can
digitalise music from records into various formats up to 24/192 and play music to the connected
PC for recording.
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I Is this update also free?
Yes, as continuous improvement and device adaptation are part of our concept. Anyone who
purchases a Devialet should own something that is always up to date.
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Matthias Böde
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