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NAD M33 Streaming Amplifier Review

pogo

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we will let you know when a fix is released.
NAD want to offer a fix. If it can really only be realized via hardware, an exchange of a board can also take place or a modification directly on a PCB. Something like this is controlled at NAD via service bulletins. My authorized NAD service point that does such work is about 15km away from me.
 

Hear Here

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Yes, yes, I remember well how they promised future updates for both the C390 and M32...for the M32 in particular, they promised Dirac support in the future, and where is it??? :confused:

NAD never said that Dirac would be available on the M32. I had one for years - great amp but I traded it for the even better M33. I would criticise NAD for saying that their module slots would make the M32 "future- proofed". The only worthwhile module was the BluOS card - a feature included within the standard M33.

Earlier you suggested that the M33 was lacking in "life". In that I would agree with you if Dirac is engaged. Sadly, as with all amps that include DSP, the extra signal processing that DSP requires sucks some of the life from the music. There are ways to avoid this, but not if you use one full-range amp to feed your speakers. Even the Dirac Live version that's supplied with the M33 adversely affects the upper frequencies although it only adjusts the sub-500 Hz range. I just disengage it as I prefer more excitement and "life" over bass accuracy any day. Fortunately I can achieve both as my speakers offer DSP within their active bass amps.
 
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Hear Here

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Which speakers do you have?

Avantgarde Duo XD. The XD software included in the bass unit's amp allows comprehensive frequency level adjustment, plus all sorts of other options such as the type of crossover and slope - Bessel, Butterworth. etc. Therefore the main amp (with DSP off) can provide its best signal to the mid and top horns and leave the bass amp to adjust low frequencies only.

The alternative is to bi-amp conventional speakers where the bass and top have their own terminals. The amp for the top should have DSP off and the bass amp could have it on.

I've tried amps with RoomPerfect, Dirac Live and MARS and all adversely affect the top end that produces the sense of live and exciting music. Turning on any of these built-in DSPs removes some of this excitement. Probably not noticeable with fairly basic speakers but a clear difference with speakers such as Avantgarde. Peter

PS this forum is full of RoomPerfect addicts who will deny that RP has any detrimental effect, but I found the Lyngdorf 3400's DSP was decidedly worse at the top end than Dirac Live. It sucks out more life from the music than DL or MARS. That's the system used in the latest Micromega amps. Lyngdorf is best kept for audio visual systems where the quality of sound is less noticed, because the brain is also dealing with its visual input and that takes priority over audio.
 
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Trondi

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Avantgarde Duo XD. The XD software included in the bass unit's amp allows comprehensive frequency level adjustment, plus all sorts of other options such as the type of crossover and slope - Bessel, Butterworth. etc. Therefore the main amp (with DSP off) can provide its best signal to the mid and top horns and leave the bass amp to adjust low frequencies only.

The alternative is to bi-amp conventional speakers where the bass and top have their own terminals. The amp for the top should have DSP off and the bass amp could have it on.

I've tried amps with RoomPerfect, Dirac Live and MARS and all adversely affect the top end that produces the sense of live and exciting music. Turning on any of these built-in DSPs removes some of this excitement. Probably not noticeable with fairly basic speakers but a clear difference with speakers such as Avantgarde. Peter

PS this forum is full of RoomPerfect addicts who will deny that RP has any detrimental effect, but I found the Lyngdorf 3400's DSP was decidedly worse at the top end than Dirac Live. It sucks out more life from the music than DL or MARS. That's the system used in the latest Micromega amps. Lyngdorf is best kept for audio visual systems where the quality of sound is less noticed, because the brain is also dealing with its visual input and that takes priority over audio.

This must be about the 40th time i have read posts from you HH, saying that you have lucked out with DSP, and that you dont like the results that they have given you. Everyone has been very patient with you. With Dirac Live in particular, they suggest you refollow the instructions to the letter when making sound measurements, in case you have missed a step or decided that you know best at some stage in the process.

I would add an extra vital step in this process. That would be to wait a month before switching DL off as your brain needs time to get used to the sound of the system, not only without room boom but also with readjusted timings for your speakers and room listening positions. This takes alot of time and patience on your part, i know, but its worth it to find as most folks do with a good amp, eg nad m33, that the top end is greatly improved from a high-fidelity perspective.

Can i suggest that any top end ‘excitement’ or ‘liveliness’ that you believe to have disappeared might in reality have not been a part of the recording but part of your dodgy room/system combo and that DL has for the first time allowed you to hear your recordings accurately for the first time. And you dont like it cos you’re not used to it?

Some ‘unexciting’ and ‘unlively’ singers often use reverb to help improve the audiences experience of their shows. In some sense are you a fan of the analogous reverb to be found within your room and system?

I ask these questions of you as you are patently swimming against the tide with so many people finding Dirac Live, esp. with their NAD M33, a revelation ito timing pace rhythm imaging.

Good luck though in gaining peace with this project HH as it must be driving you nuts that you haven’t made the most of your investments in both time and money.
 

pogo

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I ask these questions of you as you are patently swimming against the tide with so many people finding Dirac Live, esp. with their NAD M33, a revelation ito timing pace rhythm imaging.
Is it not possible that these users have a problem with the loudspeakers themselves and that matching can bring about an improvement? I know some users, myself included, who have impulse-matched and optimised speakers that sound lifeless and not real after DL optimisation. After all, you go to live performances yourself to know how it should actually sound! Interestingly, I recently had a second pair of my speakers optimised by a tuner, replacing the mid-bass drivers with faster ones. Result: My room modes are no longer excited so strongly that I was even able to deactivate my DSP correction!
DL corrects not only the room, but also the inadequacies of speakers!
 

Hear Here

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Can i suggest that any top end ‘excitement’ or ‘liveliness’ that you believe to have disappeared might in reality have not been a part of the recording but part of your dodgy room/system combo and that DL has for the first time allowed you to hear your recordings accurately for the first time. And you dont like it cos you’re not used to it?

Thanks Trondi

Yes I have mentioned my findings a number of times, but always in response to someone who has asked for opinions - on an amp such as the NAD M33 or Lyngdorf 3400 (both of which I have experience of) or about DSP in general. Incidentally since I've only posted 18 messages on this forum in total, your estimate of 40 related to DSP seems a slight exaggeration!

However looking at the paragraph I've quoted above, you seem to have misunderstood my point. The original recording quality has nothing to do with whether DSP is engaged or not. The same recording can be easily compared with and without DSP engaged.

Furthermore, remember that the Dirac Live that's included with the NAD only adjusts sub 500 Hz frequencies. This is not the spectrum where the life and excitement factor resides, The top end influences these attributes - the area supposedly not adjusted by DL. My point is that engaging DSP sends the full-range signal to the DSP processor (it must do as there's no built in crossover) and it's this processing stage that reduces the excitement factor. It's no different than engaging the tone controls or graphic equalisers in days of old - all offer advantages in flattening (or other adjustment) of the frequency curve, but this is done at the expense of pure signal fidelity.

I hope you begin to understand this. ANY extra signal processing will degrade the signal, so the fewer processing stages the better. In many systems / rooms the advantages of DSP may outweigh the disadvantages, but with extremely fine speakers that are well set up in a room where some care has been taken to avoid acoustic problems, it is generally best not to engage DSP. As I say, there are other ways to iron out low frequency anomalies that will not interfere in any way with the upper frequencies that are generally not influenced by room acoustics. Peter
 

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Is it not possible that these users have a problem with the loudspeakers themselves and that matching can bring about an improvement? I know some users, myself included, who have impulse-matched and optimised speakers that sound lifeless and not real after DL optimisation. After all, you go to live performances yourself to know how it should actually sound! Interestingly, I recently had a second pair of my speakers optimised by a tuner, replacing the mid-bass drivers with faster ones. Result: My room modes are no longer excited so strongly that I was even able to deactivate my DSP correction!
DL corrects not only the room, but also the inadequacies of speakers!

I agree with much of what you say.

Before buying my present NAD M33 amp, I bought or borrowed for home trial at least a dozen amps, so that I could best find a match for my Avantagrde speakers in my particular room. I'd be happy to send you my one line summaries for each of these amps. I concluded that the best match amongst these £5-10K amps was the NAD M32, later traded for the subtly better sounding and more highly featured M33.

As I replied to Trondi, there are better ways to get one's system singing at its best than by adding an extra layer of signal processing. Careful choice and positioning of speakers (eg not Martin Logans in my room), care to ensure the room is reasonably sympathetic to sound reproduction (mine was abysmal when I first moved in with no curtains or carpets and little soft furniture) and careful matching of amplifier (from the dozen tried in my system), all these factors should lead to a fine sounding system that doesn't need DSP.
 

Trondi

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Thanks Trondi

Yes I have mentioned my findings a number of times, but always in response to someone who has asked for opinions - on an amp such as the NAD M33 or Lyngdorf 3400 (both of which I have experience of) or about DSP in general. Incidentally since I've only posted 18 messages on this forum in total, your estimate of 40 related to DSP seems a slight exaggeration!

However looking at the paragraph I've quoted above, you seem to have misunderstood my point. The original recording quality has nothing to do with whether DSP is engaged or not. The same recording can be easily compared with and without DSP engaged.

Furthermore, remember that the Dirac Live that's included with the NAD only adjusts sub 500 Hz frequencies. This is not the spectrum where the life and excitement factor resides, The top end influences these attributes - the area supposedly not adjusted by DL. My point is that engaging DSP sends the full-range signal to the DSP processor (it must do as there's no built in crossover) and it's this processing stage that reduces the excitement factor. It's no different than engaging the tone controls or graphic equalisers in days of old - all offer advantages in flattening (or other adjustment) of the frequency curve, but this is done at the expense of pure signal fidelity.

I hope you begin to understand this. ANY extra signal processing will degrade the signal, so the fewer processing stages the better. In many systems / rooms the advantages of DSP may outweigh the disadvantages, but with extremely fine speakers that are well set up in a room where some care has been taken to avoid acoustic problems, it is generally best not to engage DSP. As I say, there are other ways to iron out low frequency anomalies that will not interfere in any way with the upper frequencies that are generally not influenced by room acoustics. Peter

Peter, i dont know where to begin.

Yes 18 posts on this site, so the other 30+ must be found on avforums on this same topic.

To ignore the points I raised and then reiterate your old misunderstandings makes it very awkward for me to respond.

What is clear through your last two paragraphs is your limited understanding of the aims of Dirac Live and how they are executed and secondly that the digital (and analogue?) world of hifi is indeed a mystery to you.

Some of your earliest posts on this topic (on avforums?) did indicate to me a desire to learn more about this subject. So can I recommend that you do some homework on the aims of Dirac Live and read some reviews of it written by people who dont get too technical to start with but rather give an overview in laymen's terms. Hopefully that will motivate you to do further studying in this area to help you be self critical with your own posts.
 

pogo

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DL also has its system limits, including the algorithms, and to judge very well-made speakers with a microphone that can also represent a bottleneck is very questionable. The DL algorithms have also become audibly better over time, but where is the end and for whom does this bring advantages or disadvantages?
For example, a B&W805 is definitely not comparable with an Avantgarde Acoustic Duo XD in terms of liveliness and other points.
 
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Hear Here

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Peter, i dont know where to begin.
.

Trondi - Likewise, I don't where to begin. It seems that you can't grasp the basic point that I'm trying to make - that any additional signal processing such as DSP will degrade the signal to a small degree. Irrespective of how much improvement can be made in the bass frequencies, where room acoustics can mess up a good speaker's performance, you also seem not to want to address my demonstrable findings that the top frequencies are adversely affected if DL is engaged, despite the fact that the DL version supplied with NAD's amps does not make any adjustment to frequencies above 500 Hz.

I agree with others that the quality of the non-calibrated microphone supplied by NAD is not ideal and I'd (we'd all) get better results by using a professional calibrated mic, but this won't change the fact that the extra processing spoils the excitement factor to a small but noticeable degree,

I have given DL (and RP and MARS) the benefit of the doubt and have taken several readings with each system, but I've always found that the sparkle offered by my speakers is slightly dulled by any of these DSP methods. I've now concluded that it's the additional signal processing that's to blame. I'd rather have slightly less accurate bass than lose some of that sparkle. I chose my speakers largely for their excitement factor after owning relatively bland but still exceptionally good speakers in the past - ATC 50 Actives, KEF Reference 107s, etc If, like me, that's what you want, then don't use this method to achieve room correction. As mentioned earlier there are better methods to achieve this, but at greater cost of course.

Should I be flattered that your only messages on this forum (all 2 of them) have been in reply to my own contributions to this particular thread?
 

SIY

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I agree with others that the quality of the non-calibrated microphone supplied by NAD is not ideal and I'd (we'd all) get better results by using a professional calibrated mic, but this won't change the fact that the extra processing spoils the excitement factor to a small but noticeable degree,

I've done that experiment. Negligible difference- the included mike is fine at low frequencies and there's EQ when using it. With a lab omni mike (I use PCB Piezotronics and Earthworks) and associated cal files, the sonic differences in the Dirac filters are low enough that I'd want to ABX them if I thought I heard a difference (I didn't).
 

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I think the main trouble with the supplied mic is that is required to be pointed up towards the ceiling. Most pro mics offer calibrations for upwards and forward facing options. I have to move overhead lights each time I take readings! However your point is taken that the supplied mic is satisfactory for the sub 500 Hz readings that are analysed by Dirac Live.
 

pogo

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the top frequencies are adversely affected if DL is engaged, despite the fact that the DL version supplied with NAD's amps does not make any adjustment to frequencies above 500 Hz.
This is not quite correct. Even with the 500Hz version, the impulse correction in DL is performed over the full frequency range. And this seems to be the bottleneck somewhere, because a deterioration should not occur.
 

SIY

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This is not quite correct. Even with the 500Hz version, the impulse correction in DL is performed over the full frequency range. And this seems to be the bottleneck somewhere, because a deterioration should not occur.
Both Kal and I heard nothing but improvement. Given his room is better than mine to start with, the improvements for me were pretty major.
 

Kal Rubinson

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I agree with others that the quality of the non-calibrated microphone supplied by NAD is not ideal and I'd (we'd all) get better results by using a professional calibrated mic, but this won't change the fact that the extra processing spoils the excitement factor to a small but noticeable degree,
IIRC, you can use your own calibrated mic if you connect it to the PC running the Dirac app.
 

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This is not quite correct. Even with the 500Hz version, the impulse correction in DL is performed over the full frequency range. And this seems to be the bottleneck somewhere, because a deterioration should not occur.

If I interpret what you say correctly, the NAD version of DL measures (impulse correction) the entire frequency range but it only adjusts the frequencies below 500 Hz. If one upgrades to the full-range version ($99 I believe), then the entire range can be adjusted. That's probably why I find it loses some of its excitement factor - the impulse correction (whatever that is) influences the un-adjustable part of the frequency range (over 500 Hz), so my claim that this extra stage of signal processing is not ultimately good for highest fidelity - in the same way tone controls, graphic equalisers, etc are detrimental to ultimate fidelity. What'ya say? It's the only reason I can find for the fairly obvious though subtle loss in sparkle when Dirac is engaged. You may prefer the sound with Dirac if your room / speakers are less than ideal, but if they are good, the problem I describe becomes more noticeable.
 

Kal Rubinson

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This is correct, and what I did to see if the supplied mike was Good Enough. It was.
OK. It was not convenient for me, so I used others.
 

pogo

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That's probably why I find it loses some of its excitement factor - the impulse correction (whatever that is) influences the un-adjustable part of the frequency range (over 500 Hz)
To suppress the impulse correction in DL I have generated an ideally measured flat curve, which can be changed as described here via a target curve:
Link

I have degraded DL to a Devialet Sweet Room and get better results.
My flat curve is the result of a bypass measurement (M33 pre-out -> mixing channel L+R to one channel as input for DL) that is used instead of a real measurement.
As a side effect you can also equalize your headphones ;)
 
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