NAD T758 V3 AVR Receiver Owner's Thread

[JStewart]

That is good to know. Thanks!

You're welcome and just in case you missed it, if you move forward with a purchase be sure to verify with the seller you'll receive one with the new AM230 board. The pic you posted above has the old one. You can tell the difference because the height output pre-amp connections are on the bottom left of the new one, unlike the pic above where they are in the top left. With the new one the voltage output of the pre-amp signal on height channels matches the pre-amp out voltage of the base layer connections. May be helpful, or even essential, with active speakers connected. If you'd like a name and number for a U.S. authorized dealer you can speak with let me know and I'll PM it to you.

 

[bkeeler10]

That's a tough one because you'd think given the price difference there'd be some compelling reason(s). The only meaningful difference I see is the number of HDMI inputs in the AVR.
I don't believe the difference in RMS wattage would result in much difference in SPL or headroom and if you needed it, for the same money you may do better with an external amp vs the 777.

Agreed that the difference in power is not terribly significant, and that same extra money spent on a multichannel amplifier will get you a lot further.

However, there are other differences between the two. The 777 comes with a multifunction learning remote. It also has an ethernet port (758 is only wifi, but you can use the USB hub to create an ethernet port IIRC). The 777 also has two expansion slots rather than the one slot the 758 has. The 758 slot is already taken by the board that has the HDMI and overhead channel pre-outs. But the 777 has that card and also has another bay to take another card. I've wondered if this could possibly allow 16 channel output in the future, although now that I'm thinking about it, I believe Atmos 9.1.6 would probably require a DSP change.

Not sure if there are any other differences though.

 

[Eric SVL]

What are you guys using your remote 1, 2, 3 presets for?

 

[JStewart]

(758 is only wifi, but you can use the USB hub to create an ethernet port IIRC)

You do. $9.99 from Amazon. The one I'm using at https://www.amazon.com/gp/product/B00MYT481C/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

But the 777 has that card and also has another bay to take another card.

Good point and who knows what the future might hold. I would add though that if you were to have owned a T758 before hdmi 2.0 and Atmos and wanted to upgrade you would have needed to purchase two MDC modules. The 4k video module VM130 $499 MSRP and the audio module AM230 $549. So for this one particular example probably better to just purchase a new or refurbished T758V3 with boards already installed.

What are you guys using your remote 1, 2, 3 presets for?

I'm going to have to take a closer look at the remote. I don't remember those buttons

 

[Eric SVL]

I'm going to have to take a closer look at the remote. I don't remember those buttons

Okay I just took a closer look as well - I was under the impression that you could set presets, and that some were using them for different Dirac curves. In fact, that's close, but not quite how it works - I read you can set 3 different Dirac curves. There aren't buttons on the remote for these presets, unfortunately. I misunderstood.

So I guess a more relevant question would be regarding how you would switch between those presets on the fly.

 

[JStewart]

So I guess a more relevant question would be regarding how you would switch between those presets on the fly.

Sorry, I should have figured out that was your question.
There's a button on the remote labeled preset. Its either the same as or near the 9 key. Press it then press 1 to 5 to select the preset.
A preset holds configuration info including one of 3 possible dirac filter sets. A preset can also be assigned to and triggered by an input selection.
Example. Selecting input 6 (blueos) triggers preset 2 which sets fronts as large from small, sets upmixer to none, sets dirac filters to #2.

There's also an IOS app that will allow direct selection of a dirac curve. In an earlier post there's a screen shot.

 

[bkeeler10]

Good point and who knows what the future might hold. I would add though that if you were to have owned a T758 before hdmi 2.0 and Atmos and wanted to upgrade you would have needed to purchase two MDC modules. The 4k video module VM130 $499 MSRP and the audio module AM230 $549. So for this one particular example probably better to just purchase a new or refurbished T758V3 with boards already installed.

So I will be picking up one of these two NADs in the next month or two. I've been debating which one it will be, and this issue is one of the biggest factors I've considered. After thinking about it a lot and going back and forth in my head, I've come to the same conclusion you do here. My primary interest in the next 2-3 years will be the possibility of going to 9.1.4 or 9.1.6 capability, which I'm nearly certain will require a different DSP in addition to more channels. So it's almost certain the 777 will not get there. Sure, I will eventually want HDMI 2.1 as well, but that could be several years out and a card upgrade to accommodate that will probably run several hundred dollars if history is any guide.

The 777 is nearly twice as expensive and its biggest benefits in my mind will cost a lot more money to take advantage of. At this point I am 90% certain it will be the 758 for me.

 

[Eric SVL]

Sorry, I should have figured out that was your question.
There's a button on the remote labeled preset. Its either the same as or near the 9 key. Press it then press 1 to 5 to select the preset.
A preset holds configuration info including one of 3 possible dirac filter sets. A preset can also be assigned to and triggered by an input selection.
Example. Selecting input 6 (blueos) triggers preset 2 which sets fronts as large from small, sets upmixer to none, sets dirac filters to #2.

There's also an IOS app that will allow direct selection of a dirac curve. In an earlier post there's a screen shot.

Thanks, that is good to know. I imagine myself going between say -20 to -40 and wanting to change to a curve that's a little more, well...curved. It should really only flatten out near reference level.

 

[Eric SVL]

Since this AVR has a single sub pre-out, can someone briefly explain to me why I need a miniDSP unit to time align my subs? Why is it not sufficient to use the phase knobs on my subs? They are only 11 feet and 5 feet from my seat. I use Line-In rather than LFE-In on my Rythmiks.

I do measure with a CSL UMIK-1 and REW.

 

[JStewart]

Since this AVR has a single sub pre-out, can someone briefly explain to me why I need a miniDSP unit to time align my subs? Why is it not sufficient to use the phase knobs on my subs? They are only 11 feet and 5 feet from my seat.

I do measure with a CSL UMIK-1 and REW.

Adjust combined response as best as possible and then run Dirac.

Never used Audyssey Sub-EQ before, but isn't that kind of how it works? ie. time align, level match and then apply EQ to the combined subs?

I use minidsp and MSO and 3 subs to get the SAME LF response at each seat. Started down that road when using no room EQ or YPAO and finding the results across the 3 seats on a sofa to be wildly different even though I could get the MLP pretty good. Problem for me was the MLP is not where I watch movies from but is the center seat for music.

 

[Eric SVL]

Adjust combined response as best as possible and then run Dirac.

Never used Audyssey Sub-EQ before, but isn't that kind of how it works? ie. time align, level match and then apply EQ to the combined subs?

I use minidsp and MSO and 3 subs to get the SAME LF response at each seat. Started down that road when using no room EQ or YPAO and finding the results across the 3 seats on a sofa to be wildly different even though I could get the MLP pretty good. Problem for me was the MLP is not where I watch movies from but is the center seat for music.

Audyssey XT32 + SubEQ AVRs have 2 separate sub pre-outs. It basically adjusts the delays of each to align them, then equalizes them together.

The NAD T758 can't do that, so you need to align them manually. I'm seeing people say I need a miniDSP 2x4. But why can't I just use the phase knobs on my subs and save the money?

 

[Sonnie Parker]

You can use phase knobs to align them... but that is not all that is needed in about 99% of the cases. You'll also need equalization, which is where the miniDSP will help.

 

[Eric SVL]

You can use phase knobs to align them... but that is not all that is needed in about 99% of the cases. You'll also need equalization, which is where the miniDSP will help.

That's true, I could make some filters and bring down some peaks. But, so can Dirac. And I have a PEQ on each sub amp good for one peak apiece (when needed).

I may just go without for a while and see how I do. If I desire one later, I can always add it in.

 

[Sonnie Parker]

The main purpose of the miniDSP would be to use Dirac Live with it... so if you already have a method of using Dirac Live, then you wouldn't need the miniDSP.

 

[Eric SVL]

Well, this is the NAD T758 v3 thread

 

[bkeeler10]

Audyssey XT32 + SubEQ AVRs have 2 separate sub pre-outs. It basically adjusts the delays of each to align them, then equalizes them together.

The NAD T758 can't do that, so you need to align them manually. I'm seeing people say I need a miniDSP 2x4. But why can't I just use the phase knobs on my subs and save the money?

As I understand it, phase knobs on subs adjust phase only at and around the crossover frequency of the sub's high-pass filter. It would have no effect on the timing at an octave below the crossover, for example. IOW, the phase knob is not equivalent to a delay that could be implemented in a DSP or in an AVR.

That said, if I were you I would probably play with the phase knobs on the subs and see if you can get a good result that way. And then, if you're struggling to get a reasonably flat response pre-Dirac, that might be the time to invest in the 2x4HD.

Honestly, for what most of us use subs for, an actual delay knob on the sub makes a lot more sense than a phase knob does. The only time I see a phase knob would be more useful is if you don't have bass management going on upstream of the sub, and you need to use the sub's crossover to filter the high end out of the sub. At that point, you would want to be able to adjust phase at the sub to get a smooth transition around the crossover frequency.

If I'm incorrect on the implementation of subwoofer phase knobs, please enlighten me

 

[Sonnie Parker]

Good point... so you were mainly just trying to figure out if you needed the miniDSP for distance/delay settings... and that would be a no.

 

[Eric SVL]

As I understand it, phase knobs on subs adjust phase only at and around the crossover frequency of the sub's high-pass filter. It would have no effect on the timing at an octave below the crossover, for example. IOW, the phase knob is not equivalent to a delay that could be implemented in a DSP or in an AVR.

That said, if I were you I would probably play with the phase knobs on the subs and see if you can get a good result that way. And then, if you're struggling to get a reasonably flat response pre-Dirac, that might be the time to invest in the 2x4HD.

Honestly, for what most of us use subs for, an actual delay knob on the sub makes a lot more sense than a phase knob does. The only time I see a phase knob would be more useful is if you don't have bass management going on upstream of the sub, and you need to use the sub's crossover to filter the high end out of the sub. At that point, you would want to be able to adjust phase at the sub to get a smooth transition around the crossover frequency.

If I'm incorrect on the implementation of subwoofer phase knobs, please enlighten me

I recall reading similar sentiment a few years ago when I set up my Rythmiks at the previous house. This would imply that it would actually not be possible to get a correct time alignment without DSP or a physical adjustable delay.

I'll do some more reading on how the process works. Thanks.

 

[Eric SVL]

Turns out, the phase knob on Rythmik subs may be a full delay and not just simple phase like most subs. Still working this out, but props to Rythmik for their forward-thinking. So hypothetically, I can adjust delays via the phase controls and get the response looking even, then run Dirac. Even if it jacks up the response (Audyssey did if you didn't start with both subs at 0 phase), I could simply adjust the sub distance in the AVR. The relative timing difference between the two subs will be preserved because the T758 v3 isn't able to control that - only the combined delay of the two, due to the single sub pre-out. Am I thinking about this correctly?

 

[bkeeler10]

IF the Rythmik knobs actually delay the full signal coming in, then your thinking is correct. Adjust delay on the further-away sub (based on distance if subs are identical make/model, or based on measurements if they are not), level match, run Dirac, adjust sub distance to get best response around crossover frequency, then take a listen.

If you find for sure that the phase knob on Rythmik subs is actually a delay, l would like to know about it. I'll be getting Rythmiks here soon myself (and the NAD 758 too).

 

[Eric SVL]

IF the Rythmik knobs actually delay the full signal coming in, then your thinking is correct. Adjust delay on the further-away sub (based on distance if subs are identical make/model, or based on measurements if they are not), level match, run Dirac, adjust sub distance to get best response around crossover frequency, then take a listen.

If you find for sure that the phase knob on Rythmik subs is actually a delay, l would like to know about it. I'll be getting Rythmiks here soon myself (and the NAD 758 too).

I will report back as soon as I can confirm with Brian or Enrico. I do vaguely recall reading about this a few years ago. It's kind of a whole new adventure when you move and set up a new room with a blank slate.

 

[JStewart]

IF the Rythmik knobs actually delay the full signal coming in, then your thinking is correct. Adjust delay on the further-away sub (based on distance if subs are identical make/model, or based on measurements if they are not), level match, run Dirac, adjust sub distance to get best response around crossover frequency, then take a listen.

Sub delay is not adjustable when using Dirac filters on the NAD. FWIW I've not found a reason to adjust sub distance after Dirac Cal on 3 different Dirac platforms, NAD, NanoAVR DL, PC version. Never read a criticism of Dirac's performance in this regard.

 

[Sonnie Parker]

Doesn't Dirac correct phase alignment of the combined sub response... or something to that effect?

 

[JStewart]

Doesn't Dirac correct phase alignment of the combined sub response... or something to that effect?

Not an expert, but like you have a bit of experience. Would probably need @Flak to answer, but if the question is Dirac aligning phase at the XO specifically with the NAD I would guess no, since the NAD Dirac implementation calibrates each speaker as large and the XO is chosen after. I'd also guess that the result of what it does has the same net effect though. i.e. proper delays should result in proper phase alignment. Changing the delay after, even if it could be done would also change the relationship between the sub and every other speaker so probably not a good idea for that reason too.

Have you ever seen the need to adjust delays after a Dirac calibration. I haven't.

 

[Sonnie Parker]

I have from time to time adjusted delay (by 5ft) when I was using Audyssey and quad subs. It would eliminate a huge null I had at 30Hz. I initially got the idea when Mark Seaton was visiting and we were experimenting. He turned one sub around and fired it into the corner... did some calculations in his head and moved one sub back 5 additional feet... smoothed the response right out... and we didn't notice anything unusual about the sound. Probably not a big deal for movies... possibly for music if it's critical listening, although I've done it even with two subs and not noticed anything odd. It hasn't been an issue with Dirac Live, although I don't have phase adjustments for individual subs anyway, so I wouldn't be able to do it. So I think you may be right in that the net effect of Dirac is somehow accounting for the differences in distance even on combined subs.