NAD M66 - finally someone makes a decent 2-channel preamp!

[ex audiophile]

Attention anyone thinking of the M66 as the ideal solution if you have genuinely full-range main speakers, plus subs for "correction" purposes -

I have just heard back from NAD Support and they confirm that the main speaker output will be subject to the same crossover as the one you choose for the subs. This means that if you choose 70 Hz for the subs (as Kal did for his Stereophile review), your main speakers will not receive frequencies below 70 Hz.

I hear you say "Just don't set an XO and the Main and Subs will receive the Full range and the subs own XO can be used". Sadly no - The Subs get no signal at all unless you tell the M66 that there are subs connected and then you are compelled to provide an XO.

This seriously disappoints me as I have full-range speakers, chosen partly for their bass performance, and I would feel cheated if they were couldn't deliver these low frequencies. This is particularly galling as the M66's predecessor, the M12 (and for that matter the M32) could be set so that the subs received only bass frequencies while the main output could optionally receive the Full frequency range.

I'd be interested to hear from anyone using the M66 with full-range speakers, or for that matter which other streamer preamp they may be using that circumvents this problem.

wow, that seems a surprising limitation in such an expensive device (I had one and returned it for other problems). Using Anthem room correction you are able to set the crossover for each speaker; I have the STR preamp and have been more than pleased. Of course it does not have a streamer, actually something I prefer and use a Node or Wiim for their excellent interfaces. It is limited to 2 independent sub outs but I really don't see using more than 2 in a 2 channel rig. Hell, the KEF app that I use with my LS wireless speakers offers both a hi pass and low pass option when a sub is employed.

 

[Nocko!]

wow, that seems a surprising limitation in such an expensive device (I had one and returned it for other problems)

Now I am curious...
I also gave back my M66 but which reasons did you have?

By the way: I was very interested in the Anthem STR but decided to go another way (I wanted Dirac...). My former Anthem Statement D2 was great with real support. I hope Anthem is still as good, as it was ten years ago.
Nocko!

 

[canjondo]

Hear Here asked about other users of the m66 running full range speakers with subs.
Here's my set-up. I use a REL subwoofer which, according to REL, is designed to work best when the speakers receive their full-range signal. No crossover is selected on the m66. The REL (tx 9) is connected to my amp (NAD m23) from whom it receives a full-range signal, or, more precisely, a portion of the signal in accordance with REL's filters (30hz-120hz). On BluOS I select No Subwoofer, very important. The crossover is strictly handled on the REL itself. Takes lots of fiddling around to get a nice integration but once it's nailed...the result is wonderful...to me.

 

[Nocko!]

Hear Here asked about other users of the m66 running full range speakers with subs.
Here's my set-up. I use a REL subwoofer which, according to REL, is designed to work best when the speakers receive their full-range signal. No crossover is selected on the m66. The REL (tx 9) is connected to my amp (NAD m23) from whom it receives a full-range signal, or, more precisely, a portion of the signal in accordance with REL's filters (30hz-120hz). On BluOS I select No Subwoofer, very important. The crossover is strictly handled on the REL itself. Takes lots of fiddling around to get a nice integration but once it's nailed...the result is wonderful...to me.

That's the traditional way to integrate subwoofers. There is nothing wrong with this way.
But it renders the M66 and Dirac DLBC useless. You could use any other (pre-) amp. That's what hear here's postings are about.
Nocko!

 

[ex audiophile]

Now I am curious...
I also gave back my M66 but which reasons did you have?

By the way: I was very interested in the Anthem STR but decided to go another way (I wanted Dirac...). My former Anthem Statement D2 was great with real support. I hope Anthem is still as good, as it was ten years ago.
Nocko!

If I created a new Dirac filter I had to reboot the M66 via unplugging to get the new file recognized. The M66 amazingly did not have an initial volume setting, so I never knew what the volume would be at startup (I listen loud occasionally). This is/was inexcusable in a unit this expensive. I found the menu system and DIRAC very tedious; all this was in comparison to the STR which has a very easy to use interface, initial volume setting, no issues with ARC. I also had no luck with NAD support. Just my experience but certainly enough to return the unit while I had the chance, albeit with a 15% restock penalty

 

[pogo]

If I created a new Dirac filter I had to reboot the M66 via unplugging to get the new file recognized.

Is that the case with all M66s? ...or did you have a 'defective' unit?

 

[Nocko!]

Is that the case with all M66s? ...or did you have a 'defective' unit?

This was one of about ten faults my M66 also had. So, yes. I think this is the case with all M66. Like the not dimmable display, the IP/TCP control, the sub latency with "analog direct" and I bet, all of the M66 will forget which screensavers were chosen by the user when they are disconnected from the mains...
Or is one of these faults gone since one of the last firmware updates?
Nocko!

 

[Nocko!]

@ex audiophile
Yes, thanks, I understand. So at least I am not the only one who found the M66 not convincing.
Nocko!

 

[Mike-48]

I'd still like to see a Roon Core MDC module

Nice idea!

 

[Hear Here]

Hear Here asked about other users of the m66 running full range speakers with subs.
Here's my set-up. I use a REL subwoofer which, according to REL, is designed to work best when the speakers receive their full-range signal. No crossover is selected on the m66. The REL (tx 9) is connected to my amp (NAD m23) from whom it receives a full-range signal, or, more precisely, a portion of the signal in accordance with REL's filters (30hz-120hz). On BluOS I select No Subwoofer, very important. The crossover is strictly handled on the REL itself. Takes lots of fiddling around to get a nice integration but once it's nailed...the result is wonderful...to me.

Thanks for responding. Interesting that you don't use the M66's Sub outs to your subs, but use the speaker-level connection from the M23 to the REL subs. This means (as I understand it) that M66 thinks you have just 2 main speakers, so its DLBC feature is not available. DL (if you are using it) measures the combined performance of your main speakers plus subs.

That being the case, you are not getting your sub individually measured for frequency response or time alignment. I suspect that may be just as good as doing the setup as NAD would recommend. What are your main speakers? Do they have big enough bass drivers that it is worth foregoing the DLBC features, or haven't you ventured down that route?

No doubt you've read Kal's review where he tested his Kef Blade 2 speakers with a 70 Hz cut-off and left these low frequencies to the subs connected to the sub outs with DLBC doing its stuff for each speaker

With my Avantgarde speakers, I'd be loath to ditch their excellent bass performance and rely on my REL S812 subs to provide the bass alone, so I'd probably be looking at a setup similar to yours. I'd probably connect the subs using a low-level connection from the "spare" (RCA) sockets on the M66 main outputs rather than speaker-level. I'd also lose the DLBC feature but it may be the preferable choice.

 

[Kal Rubinson]

That being the case, you are not getting your sub individually measured for frequency response or time alignment.............

in relationship to the main speaker to which it is connected. Not a good move.

With my Avantgarde speakers, I'd be loath to ditch their excellent bass performance and rely on my REL S812 subs to provide the bass alone,

Why? The big woofers in the Avantgardes are "sunk costs" so you have nothing to lose by trying DLBC and seeing how/if rolling them off to the RELs (say <50Hz) is an improvement.

 

[pogo]

I would bypass the DSP in the AAs and try to integrate the woofers directly via DLBC. In what range can you set the woofer crossover frequency of the AAs? I think it was +/-30Hz, but where was the center crossover frequency?

 

[canjondo]

Hear Here and Kal Rubinson, correct, when I deploy Dirac Live (I haven't tried DLBC yet as I'm still new to this), only the measurements of my two speakers are in effect (Elac Unifi-Reference UFR52 Floorstanding). During measurements I turn off the REL, as recommended by REL. Once measurements are complete, I turn the REL back on. Sounds superb (to me)...I'm aware that frequency response and time allignment are not measured on the sub but I just hear wonderful bass and music. I will venture onto DLBC if I buy a second sub. Can't imagine how much better it'll sound.

 

[Hear Here]

Why? The big woofers in the Avantgardes are "sunk costs" so you have nothing to lose by trying DLBC and seeing how/if rolling them off to the RELs (say <50Hz) is an improvement.

I am 100% sure that the twin 12" drivers in their large Avantgarde enclosure are capable of providing better bass compared with the single 12" driver (plus a 12" passive radiator) in the REL S812's considerably smaller enclosure. The intended purpose of my subs is to support the AGs and not to take away one of their main assets that have been heavily invested in. The AGs bass drivers are surely not "sunk costs". They are there to do their job - to deliver full and deep bass - not to be handicapped by the M66's unavoidable XO.

It may well be that canjondo's system could be improved even further if he relieves his Elac speaker from the lowest bass as they have much small bass drivers than his sub - as you did with your Blades. He should perhaps follow your tests by using the M66's Main outs only for his main speakers (via his M23), and connect his sub to one of the low-level Sub outs. Then he could use DL and perhaps DLBC to get his system ideally set up (and probably with less effort than manually) and perhaps delivering even better and more accurate bass. I'd be interested to hear back if he experiments further. However it's good to hear that he's already very happy with his system.

I would bypass the DSP in the AAs and try to integrate the woofers directly via DLBC. In what range can you set the woofer crossover frequency of the AAs? I think it was +/-30Hz, but where was the center crossover frequency?

If your post was in reply to mine, thanks, but I think you have misunderstood my point. The M66 CANNOT deliver full-range to the Main output and also supply a signal (either full or XO'd) to the Sub outs. Sub Outs are muted as soon as you tell M66 there are subs, but if you say No Subs, it will deprive the Main output of low frequencies - that's my gripe!

Your M33 incidentally does exactly the same. If you had the predecessors of the M33 or M66 (M32 or M12), you could do exactly what you suggest, but of course you wouldn't have DL or DLBC to help with setting up the speakers.

The DSP that's built into the AG speakers is irrelevant once the M66 knows there's a Sub present as the M66's XO nobbles the signal before it gets to the AGs!

I accept that this unfortunate feature with the M66 would only be a problem to those who have genuinely full-range main speakers, but there must be many of us.

 

[Kal Rubinson]

I am 100% sure that the twin 12" drivers in their large Avantgarde enclosure are capable of providing better bass compared with the single 12" driver (plus a 12" passive radiator) in the REL S812's considerably smaller enclosure.

I doubt that the Avantgarde can compete with the REL's in the latter's designed target low end (and I am not a fan of REL). It is not just a matter of size.

 

[pogo]

@Hear Here
In what range can you set the woofer crossover frequency of the AAs? I think it was +/-30Hz, but where was the center crossover frequency?
With AAs, bi-/tri-amping is usually possible, i.e. you should be able to use the full frequency range of the AAs with DLBC. Which AA model do you currently have?

in relationship to the main speaker to which it is connected. Not a good move.

I'm right there with you and I can't understand why people want to connect the bass range so badly.

 

[Hear Here]

In what range can you set the woofer crossover frequency of the AAs? I think it was +/-30Hz, but where was the center crossover frequency?
With AAs, bi-/tri-amping is usually possible, i.e. you should be able to use the full frequency range of the AAs with DLBC. Which AA model do you currently have?

The AG Duo XD's sub default XO is 170 Hz (though this can be changed using the XD DSP software) with back-panel adjustment possible of + or - 30 Hz. I think have mine at the default 170.

Bi amping (and maybe tri amping) is possible, but the M66 cannot deliver the full frequency range from its Main outs if it knows there are subs present.

Now, here's a thought that I hadn't seriously considered before - I could have the AG bass sections directly driven from 2 of the M66 Sub Out XLRs and the top and mid horns being considered as the Main speakers. This would entail the M66's internal XO over-riding the AG's XO, and DL / DLBC could do the fine tuning, making the AG's XD DSP redundant. If I was to keep the REL subs, they could be connected to the M66's other Sub outs. Food for thought, but I'd need to get my hands on an M66 to see if it worked!

 

[MingChops]

Now, here's a thought that I hadn't seriously considered before - I could have the AG bass sections directly driven from 2 of the M66 Sub Out XLRs and the top and mid horns being considered as the Main speakers. This would entail the M66's internal XO over-riding the AG's XO, and DL / DLBC could do the fine tuning, making the AG's XD DSP redundant. If I was to keep the REL subs, they could be connected to the M66's other Sub outs. Food for thought, but I'd need to get my hands on an M66 to see if it worked!

That is an excellent idea, as you would yield the benefit of DLBC and 4 correctly aligned sub channels, ensuring the optimum delivery of bass as a total system entity.

 

[Hear Here]

88

That is an excellent idea, as you would yield the benefit of DLBC and 4 correctly aligned sub channels, ensuring the optimum delivery of bass as a total system entity.

I am now a little more inclined to take the M66 plunge, as this thread seems to have opened up the possibility that my AG speakers can deliver the full range and still take advantage of Dirac, with or without extra subs.

However, I have Dirac Live in my M33 but I chose not to engage the filters because I find there's a slight loss of top-end sparkle whenever the Signal is Digitally Processed.

This is despite the version used by M33 ADJUSTING only sub 500 Hz, yet the ENTIRE signal has to pass through the processor - there is no "top-end bypass". With highly detailed speakers capable of supplying sparkle in bucket-loads, I (and others who've listened) detect a small but noticeable reduction in this sparkle - enough that I prefer the non-processed signal.

I'd be interested to hear other users' experiences to see if they find the same - I know of others who do. Choose a bass-light track that has excellent "tingle-factor" top end and play this track with a sub-500Hz Dirac filter, ideally one that makes no adjustments at all to the frequency response. Listen attentively to this top-end sparkle. Then play the same track with No Filter.

Despite the processing being done in the digital domain, I am convinced that the Dirac processor (and others such as RoomPerfect) slightly damages the signal, despite not adjusting the response above 500 Hz. If you have "tingle-factor" speakers, see what you think - I'd be very interested to hear your honest and frank findings.

 

[Nocko!]

@those with Dirac:
I think there is to much theory in here. Why don't you simply measure your main speakers with Dirac and show the results here?

Then we could see where there are problems in the room and can discuss if it makes sense to enable subwoofers and / or DLBC.

And I think there is another misunderstanding here: DLBC always suggests a crossover at 70Hz. That was by far to high for my system but with a lower crossover I've got quite good results. And again: Don't think of the crossover as a "brick wall" or "stop sign". The slope seems to be quite reasonable and is perhaps variable. Although this is not documented by Dirac.

Also it seems to me as if a few here are still used to the far too boomy bass that most mighty speakers produce in a room. So it would be really interesting to see some measurements.
Nocko!