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Review and Measurements of NAD T758 V3 AVR

SimpleTheater

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My point always was that DIRAC could make more difference in the final result than a lousy THD could. Please see this link, its subjective, yes, but it´s a real world situation. A cheap component with lousy measurement against a monster audiophile component:

http://matrixhifi.com/ENG_contenedor_ppec.htm
First, thanks for the link.

Second, you have to get out of the mindset that "expensive" equals quality. The YBA 2 was tested by Stereophile and is generally a lousy amplifier with large amounts of distortion (though that didn't stop it from getting a 'Highly Recommended' at the conclusion of the review).
https://www.stereophile.com/solidpoweramps/420/index.html

I've contacted an engineer and I'm pricing how much it would cost to update this Sherwood RD-7503 7 channel receiver with Dirac. It shouldn't matter how bad it tested, because Dirac will fix all the problems. I can get hundreds of these units for about $1 each, so if Dirac implementation can be done for under $500 w/licensing costs, I can sell these for 100% markup and make a lot of money selling them. If I need investors, I'll post, but can I count on your order?
https://www.soundandvision.com/content/sherwood-rd-7503-av-receiver-ht-labs-measures
 

617

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The idea that an AVR with Dirac and poor quality DACs would sound better than one with less sophisticated room correction and better DACs is totally reasonable. This is not a hifi product. It probably sounds great in ordinary use.

Let's dial back the personal stuff if possible. In particular I find the researching of user post history on other forums to be really distasteful.
 
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amirm

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All the rant here began when I suggested to give the NAD a try. Yes, I was wrong (as I already said to Amir) when I thought DIRAC could lessen distortion, but that doesn´t invalidate my conclusion that, even with the poor measurements of this AVR, DIRAC still manages to make it a great sounding device in a real world situation.
A point that was made right in the review: [bolding now]

The NAD T758 comes with Dirac Lite room equalization which if it works right, should make it audibly perform better than many AVRs that use lesser systems.
 

speedy

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A point that was made right in the review: [bolding now]
Agreed that Dirac is impressive, but I've A/B'd the NAD T758 against the Denon AVR-X3500H in my own home under no time pressure (used to own both of them) and personally felt that the T758 sounded significantly better than the X3500 even with Dirac off.

I think a number of members here have expressed that they think the Denon products (X3500 was mentioned) will measure much better than the NAD T758. I'm looking forward to the eventual testing that shows/explains this.

A big portion of why I'm here though is to learn about the correlation between the technical/measurable attributes that result in certain products sounding good vs. bad. The reason I'm continuing to follow this thread has nothing to do with wanting to observe many members bicker back & forth, but rather everything to do with wanting to understand why a product that I think sounds good like the T758 measures so poorly.
 

GrimSurfer

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The idea that an AVR with Dirac and poor quality DACs would sound better than one with less sophisticated room correction and better DACs is totally reasonable.

Dirac is designed to deliver Digital Room Correction, Sound Optimization and Sound Field Control. It does so by manipulating frequency and phase. It does this very well by all accounts but it can no more reduce distortion or increase dynamic range than a pig can fly.

Using the term "sound better" is synonymous with "more pleasing", which is wholly subjective.

Amir's review has very little to do with subjectivity. @amirm provides the results of objective measurement. His recommendation is based on a comparison of these objective measurements with the objective measurements of other consumer electronic devices.

Nobody expects a $1500 AVR to outperform everything else in the market but it is reasonable to expect that it will manage 16 bits of resolution and at least average levels of noise, distortion etc. Alas, the NAD T758 did neither of these things.

The first counter argument asks that people ignore all of this and buy/try or listen. The second counter argument is that the basic product may not perform but the add-on Dirac circuitry makes up for this. The third argument is that the T758 sounds better than products without Dirac.

The first argument is illogical. The second argument is technically wrong. The third argument is weak but may have merit... but his doesn't mean that the T758 is good. It just means it could sound better than "another" product, which nobody would challenge.

Based on @amirm 's review, I wouldn't buy the T758. I'd look for something better. Why? Because for me, it's not about the money. Paying any sum of money for a product that performs poorly does not represent value in any way whatsoever.
 
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SimpleTheater

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I've A/B'd the NAD T758 against the Denon AVR-X3500H in my own home under no time pressure (used to own both of them) and personally felt that the T758 sounded significantly better than the X3500 even with Dirac off.

The reason I'm continuing to follow this thread...[is]... wanting to understand why a product that I think sounds good like the T758 measures so poorly.

We first have to see if the Denon measures well, it could measure far worse. I was very content with some of my earlier AVRs as you appear to be with the T758, and if you don't want to chase the dragon to audio perfection (which, BTW, doesn't exist), I recommend you turn back now, as it will cost you lots of money in upgrading over and over again. Today I'm extremely pleased with my two-channel setup and my completely separate home theater setup, but most of my time now goes into ensuring my room is good, not my equipment.
 
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amirm

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Agreed that Dirac is impressive, but I've A/B'd the NAD T758 against the Denon AVR-X3500H in my own home under no time pressure (used to own both of them) and personally felt that the T758 sounded significantly better than the X3500 even with Dirac off.
Unless you can make instantaneous AB switching with levels matched, it is impossible to hear small differences we are talking about here. And that is not easy to do with multi-channel AVRs and no external equipment.
 

617

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Nobody expects a $1500 AVR to outperform everything else in the market but it is reasonable to expect that it will manage 16 bits of resolution and at least average levels of noise, distortion etc. Alas, the NAD T758 did neither of these things.

I think this comment highlights the need for different thinking about products which engage so intimately with imperfect devices like rooms and speakers. You are absolutely correct that this product is suspect, but the performance it offers is sufficient to sound better than other, presumably better measuring products.

The measurements Amir provides allow for useful comparison but they do not really characterize AVR performance very well when so much of the performance depends on sophisticated room correction, which has far more audible effect than any flawed DAC or amplifier.

These types of measurements are ok for measuring in a headphone context, where sound can be scrutinized intensely by the listener, but different metrics must be applied to AVRs. Dare I say that listener preference may be the best way to evaluate room correction? Of course such preferences are hard to tabulate, so we will continue to evaluate AVRs based on what an audio analyzer says about them, which is unfortunately not that much.

A question I would pose to experts here - what kind of dynamic range and distortion is actually acceptable for a domestic amplifier given the high noise floors of living spaces are typically around 40dba, and loudspeaker distortion is much worse than any DAC or Amp (although this DAC is getting pretty close...)
 

617

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FYI, I plan to buy the Yamaha RX-A1080 to test....

Amir, that is an excellent choice in my opinion - Yamaha specifically advertises DAC quality with their AVRs, and lists the following as a feature:
"ESS SABRE ES9007S Premier Audio DAC for high performance conversion"
 
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amirm

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A question I would pose to experts here - what kind of dynamic range and distortion is actually acceptable for a domestic amplifier given the high noise floors of living spaces are typically around 40dba, and loudspeaker distortion is much worse than any DAC or Amp (although this DAC is getting pretty close...)
Room noise is mostly in low frequencies so it is mostly inaudible. See: https://www.audiosciencereview.com/forum/index.php?threads/dynamic-range-how-quiet-is-quiet.14/

So the minimum noise floor is 0 to -10 dBSPL (at mid-frequencies where our hearing is most sensitive). The dynamic range is then dependent by how loud you would want to get. Using the class 105 dB THX/Dolby standard (?) you would need 105 to 115 dB of noise-free dynamic range. If you play louder, you easily get to 120 dB or 20 bits (see the references in my article above).
 

617

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Room noise is mostly in low frequencies so it is mostly inaudible. See: https://www.audiosciencereview.com/forum/index.php?threads/dynamic-range-how-quiet-is-quiet.14/

So the minimum noise floor is 0 to -10 dBSPL (at mid-frequencies where our hearing is most sensitive). The dynamic range is then dependent by how loud you would want to get. Using the class 105 dB THX/Dolby standard (?) you would need 105 to 115 dB of noise-free dynamic range. If you play louder, you easily get to 120 dB or 20 bits (see the references in my article above).

That's really interesting, Amir. Thanks for the link. I am familiar with the THX standard and when I design speakers I normally try to hit it for the useful bandwidth of the speaker at 15 feet or so. It's worth noting that to get levels this high at those distances you need pretty good speakers - lots of midbass surface area. Of course my estimations are anechoic but still a useful guideline.

I suppose then it is reasonable to say that although the NAD probably sounds great at low volumes it quickly falls apart at the levels you would expect an AVR at this price point to reproduce.
 

xhattan

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You don't.

Your suggestion to try the 758, following scientific measurement, is about as logical as me suggesting that anyone "try" jumping off a tall building.

You show an unwavering penchant for subjectivity. Perhaps this is not the place for you.

So, objectively, which AVR would you recommend. Oh wait. I forgot. No AVR is good enough here, unless you spend 40 thousand dollars...
 

RichB

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So, objectively, which AVR would you recommend. Oh wait. I forgot. No AVR is good enough here, unless you spend 40 thousand dollars...

Whatever you own is good enough for me :p

- Rich
 

digicidal

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Amir, that is an excellent choice in my opinion - Yamaha specifically advertises DAC quality with their AVRs, and lists the following as a feature:
"ESS SABRE ES9007S Premier Audio DAC for high performance conversion"

I wonder if that's a special SKU just for Yamaha or ?? The premier line has had the 9006, 9006S, and SABRE9006AS - but there's no ES9007S anywhere on the web other than Yamaha references that I can find. Weird.

I suppose then it is reasonable to say that although the NAD probably sounds great at low volumes it quickly falls apart at the levels you would expect an AVR at this price point to reproduce.

Especially if you're using it to drive 5/7 speakers of lower sensitivity to those levels. Although I think most listeners striving for the full THX experience in their home... aren't doing it with gear this modestly priced. I could be wrong in that, but I'd guess the average target for this NAD AVR is more the "family room at 90dB maximum" kind of person. And for that person... I'm sure this will be a fantastic sounding piece of gear - much better than the BT soundbar on their other TV.
 

digicidal

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So, objectively, which AVR would you recommend. Oh wait. I forgot. No AVR is good enough here, unless you spend 40 thousand dollars...
There are literally hundreds of "good enough" AVRs - they're the ones 99% of consumers buy without even comparing them to anything. They walk into their local big-box electronics store... pick one mostly on price... then get talked into the slightly more expensive model by the salesperson. They leave and hook it up and enjoy great sounding movies and music for years.

Those people aren't interested in measurements, nor actually in comparisons of any kind - they just want good sound and convenience. They don't even really care if they could have gotten something objectively "better" - they're already done with the shopping part, so it's out of their mind.

The remaining 1% are here - hoping to get a better level of performance or accuracy than "good enough" - but also being aware that simply buying the most expensive component in a particular category isn't any guarantee of that. It seems like you are mostly in the first group, but are interested in being in the second.

If you like what you hear, then who cares if even the whole world writes bad reviews or posts poor test results? You like it - so go listen to music and movies on it and grin! If you are interested in the very best technical performance possible in your personal budget... then strap in and sack up... because there's gonna be a lot of bad reviews between here and that aural utopia down the road. At least half of my "audio darlings" from when I was in the first group - and a few from after as well... didn't fare well here at all. Not a big deal really... they can't (and definitely won't) all be winners.

Plus there are plenty of times when you just need something now... and as long as it works and is convenient - who cares? Objectively speaking there can't be "good enough" in a conclusive sense - that by definition is a subjective qualification. Good enough for who, in which way, under what conditions? And while we're at it... how much exactly of good is truly enough? ;)
 
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Dj7675

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So, objectively, which AVR would you recommend. Oh wait. I forgot. No AVR is good enough here, unless you spend 40 thousand dollars...

With a few clicks you can see there haven't been very many av receivers/prepros testing. If my count is correct, only 8.
Testing here has primarily been separates like amps, dacs, etc and not receivers. While the ones measured so far haven't seem to have tested well so far, it seems quite the leap to say none will. I am quite interested in the upcoming Anthem MRX520 review as well as one for an upcoming Yamaha model. It will be interesting to see what companies are putting in the effort to at least hit the 16 bit/cd quality threshold.
We all should want the best engineered devices at the given price points and if manufacturers are aware that their products are getting measured in this way, it may result in better gear in the long run. It should be something everyone would be in favor of.
 

Blumlein 88

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That's really interesting, Amir. Thanks for the link. I am familiar with the THX standard and when I design speakers I normally try to hit it for the useful bandwidth of the speaker at 15 feet or so. It's worth noting that to get levels this high at those distances you need pretty good speakers - lots of midbass surface area. Of course my estimations are anechoic but still a useful guideline.

I suppose then it is reasonable to say that although the NAD probably sounds great at low volumes it quickly falls apart at the levels you would expect an AVR at this price point to reproduce.
I once posted files with filtered noise added at different levels asking people to see at which level the noise disappeared. Most people listen at 75 db or 80 db average levels. Most reported the noise could be heard down to 70 or 75 db below the signal. Which fits in nicely with our in room noise sensitivity in our most sensitive range being somewhere around 10 db SPL or so in domestic listening rooms.

I think another thing worth thinking about in regards to Dirac. A certain poster wants to imply it is more important than base level performance. It could be a big help. But is a variable. If you have speakers that dipped a bit in the 3-5 khz range, and Dirac fixes that guess what? It may have just pushed some marginally inaudible distortion the NAD has into a audible level by boosting response in that range. If this NAD were paired with inefficient speakers so you are pushing levels pretty good you'll have just corrected yourself into distortion. It still might sound better if it fixes FR even with distortion if it isn't too nasty. I've said before FR is 85% of hifi.
 
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