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Review and Measurements of NAD M17 V2 Pre/Pro

amirm

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#1
This is a review and measurements of the NAD M17 V2 Home Theater Surround Sound 11.1 channel preamplifier and processor ("pre/pro"). It is kindly loaned to me by one of our members. The M17 V2 is a high-end unit, costing US $6,600.

Unlike a lot of AVRs and processors I have tested, the M17 V2 oozes audio luxury with a very attractive enclosure and gorgeous display:

NAD M17 V2 Home Theater PrePro Processor and Surround Sound Audio review.jpg

As much as I love and appreciate the work that went into the aesthetics of the unit, it reminds me of a review of BMW 7 series. It said, "this drives so well it is a shame that the owner will likely sit in the back and let someone else drive it." By the same token, in a home theater application you want a dark room and likely will hide this beautiful piece of audio machinery hidden some place.

The display is not only beautiful and large, it is also very informative. I very much appreciated the constant indication of audio and video resolution and format. The former allowed me to catch a very strange anomaly in the way my PC was sending audio to it which I fixed. This information is always available inside these processor and AVRs. It is a shame they don't always display it.

The screen is touch sensitive although I mostly used the remote control for control. The remote is super heavy and long. I know they wanted to give the feeling of quality but I take a more ergonomic plastic one over this. There are sharp corners and I would worry about dropping it and denting a wood floor, or breaking a glass table. Minor complaint.

Here is the back panel:

NAD M17 V2 Home Theater PrePro Processor and Surround Sound Back Panel Audio review.jpg


In my opinion balanced XLRs are mandatory in any audio product that claims to be high performance and there are here of course. That is what I used for my testing. For inputs, I focused on Audio 1 analog input and HDMI. The processor happily synced with my computer and passed through its "4K" resolution through without affecting its frame rate. Researching online though, I saw some complaints about HDMI compatibility. Such things are unfortunately a fact of life with HDMI, more so on some products than others.

Processor DAC Audio Measurements
It was with much anticipation that I powered on the unit and ran my dashboard tone of 1 kHz/24-bit through it:
NAD M17 V2 Surround Sound Preamp Processor Home Theater Audio Measurements.png


For balanced XLR outputs, stand-alone DAC usually output 4 volts or more. This is half as much so I boosted the volume to +6 dB to get that:

NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Audio Measurements.png


That got me the 4 volt I needed and gave a boost to the performance of the M17 V2. It increased its SINAD (signal over noise and distortion) to 96 dB. This is all dominated by high second harmonic distortion and just a bit of noise. Can't imagine the DAC they are using has this much harmonic distortion so likely this is the amplifier buffer/gain stage or analog switcher that is causing it. That is my guess at least until NAD chooses to communicate with us and explain why an audio product costing over $6000 can't outperform a $9 apple phone dongle. As it is, the M17 V2 does well relative to other tested AVRs and processors:
Best Home Theater AVRs and Processors Reviewed and Tested.png


In the larger context of all DACs of different types tested so far, the overall ranking is underwhelming:

Best Audio DACs Reviewed and Tested 2019.png


I hope one day we see one breaking into green bucket. Not holding my breath on blue (top class).

Jitter and spurious noise performance shows poor hygiene when it comes to the design:
NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Jitter Audio Measurements.png


The larger picture is the first measurement which clearly shows some symmetrical components which usually indicate jitter. Later, I happen to run this test again (inset) and notice how the spikes to the left have completely changed! This shows that internal activity in the unit is bleeding into the output of the DAC. This could be HDMI picture related content, microprocessor servicing front panel or other sources. Either way, I would be unhappy if a $100 DAC did this let alone such an expensive processor. Fortunately the levels are below -110 dB so not an audible concern. It is like a hanging nail. You are not going to die from it but it sure is annoying to see.

Here is what the background noise level looks like with no signal driving it:
NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Noise Spectrum Audio Measurements.png


Shouldn't be seeing power supply related noise. The spike at 1 kHz should not be there either. The curve up is fine and is part of the noise shaping in the DAC to push noise into inaudible range. There is however a spike all the way to the right that should not be there. Its level is -76 dB or so. As such, any measurement that includes that much bandwidth will show that, instead of true distortion. Such is the case when we run our THD+N versus frequency with bandwidth of 90 kHz:

NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB THD+N versus Frequency Audio Mea...png


Lowering measurement bandwidth to 45 kHz (green) eliminates that factor. But noise shaping still increases the overall THD+N. And whatever other distortion may be there. Overall, it is a poor showing with respect to controlling ultrasonic content and distortion.

Dynamic range is "decent" clearing 16 bit content:

NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Dynamic Range Audio Measurements.png


Frequency Response is flat to in audible band and extends quite a bit indicating lack of resampling when all effects are turned off:
NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Frequency Response Audio Measure...png


Here is the filter response for each sample rate supported over HDMI:
NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Digital Bandwidth Audio Measurem...png


Yet again we see levels are reduced the higher the sample rate becomes. Why? 192 kHz is some 7 to 8 dB lower in volume.

Multitone test (32 tone signal) replicates what we already know as far as distortion:
NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Multitone Audio Measurements.png


Linearity is poor relative to what even $100 DACs can produce:
NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Linearity Audio Measurements.png


Investigating that at 1 kHz, the level would constant go up and down. Even averaging it didn't help. So it is both noise and deterministic error.

Intermodulation distortion versus level was reasonably good:

NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB IMD Audio Measurements.png


Since I ran this test at +6 dB, most optimal volume control level is around -2 dB although the penalty is quite light in going beyond that to 6 dB.

Analog Input Audio Measurements
In case you are tempted to use an external DAC and feed it to the M17 V2, I performed a few measurements of that. The M17 is nice in that it gives you a choice of sampling rate so I set it to 192 kHz (highest rate) and here is what we get:

NAD M17 V2 Surround Sound Preamp Processor Home Theater +6 dB Analog Audio Measurements.png


I was surprised how low the output level was at 0 dB volume. I am feeding it 2 volts, how come I am not getting 2 volts out? I had to boost the level to nearly max of 25.5 dB to get to 4 volts out:

NAD M17 V2 Surround Sound Preamp Processor Home Theater 25 dB Analog Audio Measurements.png


Overall performance does not change though, producing a very disappointing 73 dB SINAD. This is a throw-away input suitable for perhaps an old game console or your VHS player. I jest of course but come on. How can you have so much harmonic distortion here? We are taking a 23 dB hit by feeding the unit analog instead of digital signal. Noise I could understand going up but distortion?

Needless to say, intermodulation distortion versus level was quite horrible:

NAD M17 V2 Surround Sound Preamp Processor Home Theater Intermodulation distsortion versus lev...png


To cover all bases, I also tested with volume control set to 0 dB and there, the very low output level reduces performance (green).

Frequency response test confirmed high sampling rate was indeed used:
NAD M17 V2 Surround Sound Preamp Processor Home Theater 25 dB Analog Frequency Response Audio ...png


One bright spot was crosstlak versus frequency:
NAD M17 V2 Surround Sound Preamp Processor Home Theater 25 dB Analog Crosstalk Audio Measureme...png


Conclusions
The good looks of the NAD M17 V2 is undeniable. Proper homework and investment in tooling and case was made to produce a truly gorgeous product. No doubt this compelled me to go easier on the measurement result, giving it the "good" pink panther moniker. But really, in the context of producing a clean, 12 channel DAC with processing NAD fails with M17 V2. No wonder they provide no specifications whatsoever on performance of the DAC. Either they don't measure it or measured it and know it doesn't make for good marketing. We are talking DAC performance that barely matches the Pioneer VSX-LX504 AVR. A processor is designed to give better performance than an integrated AVR.

Once again as I have noted in the past, the DIrac Room EQ is a major plus here and should in practice produce excellent sound. Just don't go around bragging to your friends that you have a best design audio/video processor. So much low-hanging fruit was left in the design of M17 V2.

These companies need to hire an anal audio performance czar to review the product and have veto power over its release. Only then are they going to make progress toward making excellently engineered products. There can be strong competitive advantage for the first home theater company that gets there.

FYI I also have the companion power amplifier to test.

------------
As always, questions, comments, recommendations, etc. are welcome.

The owner wants this back very soon so I have to drive it to him. Roundtrip this is nearly 200 miles. I need gas money folks! So donate generously using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

esm

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#4
Every time one of these AVR tests scrolls past, I'm reminded of how glad I am that I decided to use a UDP-205 as my "AVR", and add on room eq and HDMI switching as separate devices.
 

amirm

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#5
Every time one of these AVR tests scrolls past, I'm reminded of how glad I am that I decided to use a UDP-205 as my "AVR", and add on room eq and HDMI switching as separate devices.
Definitely. The UDP-205 is so much better than these that you can't put them in the same sentence...
 

RichB

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#7
I'm am not surprised though. Top-notch measured performance is unlikely in products that do not publish performance specifications.

- Rich
 

vkvedam

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#8
Thanks @amirm , that sort of hits the nail on NAD's coffin for me. Atrocious! :facepalm:
 

maty

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#10
BTW, I can see the famous harmonic profile of some warm Class A amps, with H2 at -73 dB. With that profile it is assumed that recordings with a few acoustic instruments will sound great, which will hook the listener aka emotion.

But more complex recordings like electronic or orchestral will embody the sound, which is what Nelson Pass warns of what happens with that profile. A winning product would be one that could have both profiles, this one and other free of harmonics, I say... many times, but seems that nobody listens.

H2 at -84 dB would be a good compromise.

 
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#11
Every time one of these AVR tests scrolls past, I'm reminded of how glad I am that I decided to use a UDP-205 as my "AVR", and add on room eq and HDMI switching as separate devices.
ESM,

for noobies like me, could you provide a little more detail on hookup. thanks!
 

audimus

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#12
As much as I love and appreciate the work that went into the aesthetics of the unit, it reminds me of a review of BMW 7 series. It said, "this drives so well it is a shame that the owner will likely sit in the back and let someone else drive it." By the same token, in a home theater application you want a dark room and likely will hide this beautiful piece of audio machinery hidden some place.
And when people commented on the ugly butt on the Chris Bangle designed version of the 7 series, the salesmen said “this drives so fast that the only people who will see the behind of a 7 series are the other drivers you will be passing”.

I think NAD sales will have a similar response to these measurements - “it costs so much that the only people who will see those measurements are people who were not going to spend that kind of money on this”. ;)

But this segment ($5000-$10000) is getting very crowded in the next 3 months with ATI itself supplying about half a dozen white labeled variants of 16 channel pre/pros. If one of them manages to get it clean and if they are smart (which is not always the case), they will make the clean numbers the major marketing talking point since they are all similar feature-wise. But that assumes, it is possible to make a feature rich unit with multiple circuits in a single box as clean as a stand alone DAC that does nothing else. I don’t know the technical issues involved.
 

Timbo2

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#14
And when people commented on the ugly butt on the Chris Bangle designed version of the 7 series, the salesmen said “this drives so fast that the only people who will see the behind of a 7 series are the other drivers you will be passing”.
I view "Bangle butt" as the beginning of the end of BMW. I'm not sure where such a point would be with NAD.
 

RichB

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#17
UDP-205 is out of my price range. how does UDP-203 fare compared to 205?
They are out of production so the price is high. The 205 has better specs and fully balanced XLR outputs for 2 channel. You can still google the specs of each to locate the product pages.

- Rich
 

digicidal

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#18
UDP-205 is out of my price range. how does UDP-203 fare compared to 205?
You can see the comparisons direct from them here. All I can tell you is that the 203 may not be as impressive - but I'd virtually guarantee it would measure better than this (or any other obviously) NAD unit. LOL! For a $550 player, it's fantastic... at current amazon/ebay prices - I'd probably pass on either of them honestly. Oppo did really great jobs on their optical players (and many other things IMO) but to pay $2-4K for it - dunno.
 

Blumlein 88

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#19
I don't know this is why the analog input here is so noisy, but I think basic housekeeping likely explains this and other aspects of poor AV performance. A few years back a fellow had one of the Denon units. He wanted to use the analog input for RTR. Only that input had SNR in the low 50's. Noticeable even with his tape source. He investigated it. Found the power supply traces to connect to several devices and were suspiciously small. He snipped the PS traces at the daughter board of the ADC chip. Used CAT 5 to connect to the source of power for those traces on multiple boards. Then placed some capacitors on the daughter board (which was one tight fit). The ADC chip among other things was starving for current according to him, and being fed about as much noise as clean power. This simple change of twisted small gauge wire and some capacitance boosted the SNR into the mid 90 db range.

Now you'd hope they could or would go the extra step on housekeeping on these multi-thousand dollar products, but they don't. They seem to get only a fraction of the performance that their digital chips are capable of getting.

I know it isn't something you'd want to do on every unit reviewed by you, but think it might be instructive to investigate how dirty or clean the power supplying the digital chips is in these devices? Or the power supply to analog output buffer circuits?
 
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