Current NAD AV receivers are not THX-certified. While some might argue that THX certification is an assurance of delivering a minimum level of performance, this generally isn't a concern for NAD's receivers, which offer pretty robust power output. There are some other aspects of THX certification as well, such as surround sound post-processing, but many manufacturers have their own version of this sort of thing. For receivers whose power output may be potentially questionable, the THX "badge" may provide some consumers with a little more confidence. However, for a line like NAD or Rotel, since THX licensing obviously adds to the cost of each unit, you are probably better offer saving the money.
Daniel Benatar
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Posted on
Jesse Roman,
Please see my note about NAD and THX certification in this forum under - Why not to buy NAD.
And it contains the following:
As I owned NAD stereo amplifier I didn't experience any issue with my NAD unit. This is why I asked this forum about the amplifier 973 unit. And as Hawk wrote, the 973 amplifier is build differently than the T773 receiver, so I went and audit the 163 preamp with the 973 amplifier and I heard the hiss noise same as it is from my NAD 773 receiver. So bottom line, I don't know if there are free hiss noise units from the current models of NAD stereo, amplifier and receiver. All these units 773 reciver, 973 amp and the 163 preamp are not THX certified units.
In addition, I do know that my old NAD stereo receiver was from England. Today, and please correct me if I wrong, from what I have read, the NAD company was changed the owner, at the early 90' used to owned, developed and manufactured at England, but around end of the 90', the company changed owners and moved to Canada (headquarter), and most of their manufactories are China based. If I remember right, in the early 90' NAD trended up with the development, sound and sells and even revenue. Today, I think that what left from NAD is only the great name and reputation they used to have in the 90'. And just short comparison with my friends in US and in Europe, shows me that that today ARCAM have the same trend up from sound, quality, market share, sells and revenue. And this is not surprising me! As ARCAM, owned by British company has the same approach for costumer first as NAD used to have. And that's my friends is making the different, especially for long term.
Let me try and answer your question about signal to noise, although, I will start that I am not an engineer and my background is from Physic and Math, and all, please feel free to correct me. When you develop and try to build an amplifier system, you would like to insert to the box a small electronic signal or amplitude and to increase it by using electronics devices (mainly transistors) and have the output amplitude signal increase by factor X. For this, you will need all the time to keep your input signal clean from noise. Let's say that your input signal is not clean, you will have the noise increase by factor Y and then, your signal to noise will be X/Y. This is what we call signal to noise ratio. Now, pay attention that I wrote that the noise is increase by different factor to the input amplitude signal, and this is mainly due to capacitors using in the receiver or amplifiers systems, to try and clean the noise as much as possible while increasing the input amplitude signal. Ok, now that we agreed on the signal to noise ratio, some of the companies are not doing good work with keeping the in put noise low post the amplification, and some of the companies are not doing a good work with keeping the amplification process clean from noise. And d not be naive, in all the amplification process there is a noise. There are no amplification process free noises. Now, in the receivers units, since there are more electronics devices inside the units, for the amplification process, for the radio, and for the preamp processor as well, the noise level is higher than in the just amplifier units. Remember, as much as the amplifier is simple from amplification process as much as the signal to noise is better. In high end amplifiers, you will not find (almost) many electronics devices inside the unit, and you will find tubes doing the amplification process.
Return back to NAD, I think that NAD with their honesty and the run after the high watt out put receivers lost the ability, either to keep the incoming noise low, or lost the ability to keep the noise low from the unit electronic devices. In the early 90' NAD used to do it very well with 2 channel stereo amplifiers, as it was not so complicated like today with 5 or 7 channels receivers. The trick today is to keep the watt output high, clean sound and with reasonable signal to noise ratio. And its not simple. I think that a starting point, NAD need to listen to her costumers, understand what are their expectations from the unit, and how is the actual unit performance against the expectations. And that my friends, NAD is not doing at all, and therefore, I predict (if I can write so) that within 2-3 years, companies like Rotel and ARCAM will take all the market share from NAD. By the way, there is no competition between Denon, Yamaha and NAD as in my mind people who like NAD will move ever to Yamaha or to Denon (and vise versa), they just will move to Rotel and ARCAM, and this is the biggest issue for NAD. And another point of thinking, although, I think (for me) overall that NAD sound is better than Yamaha, I do think that Yamaha is doing an excellent work with reducing to minimum the noise level in their product (see RXV1500 and RXV2500 models).
And from here, lets go back to THX:
It's a weekend and I have time to write again. Well I continue to take a look into the NAD receiver more closely and deeply. I know that some of you think that THX certification is not so important to have this sign on the receiver. I partially agree with you, but just if this is a good receiver with very low signal to noise, and the company don't want to pay more money to certify their product through THX and not to increase the receiver price.
Let me take you back 10 years, to you my friends as worked in the high tech industry, you probably remember the ISO9000 certification. If not, I can tell you and make it short: at the beginning of the 90', there was a trend of ISO9000 certification, and basically, company from England certify high tech factories with ISO9000, the concept was simple (and even today), make sure that your product complete the process in high quality manner, and to achieve it, the high tech factories needed to document everything through procedures and specifications. For every activity, the high tech needed to have well documented procedure that all employees must know it, from the factory manager all the way down to the engineering and technician. And many high tech factories worked hard to achieve this ISO9000 certification.
You probably ask, why this related to NAD and THX. Well, my friends, after looking very carefully on NAD products, most of them with the current signal to noise and quality sound issue like hiss and hum will not be able to be certify with THX. And, yes, it's not about the receiver price or like Hawk wrote that NAD building their product with very sensitive devices to achieve better sound performance - its about the ability of NAD to make receiver with very low signal to noise ratio. Yes, they have the silver line certified by THX, but these products are relative old, and are not represent the majority of their line products. I audit the NAD T163 and the 973 amplifiers, and I must admit it sounded good and better than the T773, but it was noisy as well with hiss - while the ARCAM THX preamp with the amplifier (although the price is higher) smokes the NAD away, and I could not even hear from 20cm from the speakers any hiss noise.
I think that if NAD wanted to return back to business, they should do three things: 1. Reduce the S/N ratio. 2. Be certify by THX. 3. Do not increase the price. Simple steps. With all my empathic to NAD, I think that within 3-4 years, they will loose the market to Rotel and ARCAM, companies with the same price range, very good quality units, very low S/N, very good features and with overall same sound quality.
Let me finish with the ISO9000, yep, the high tech that certified by this England company, grow up, had more market share and sell more products due to higher quality than company without ISO9000 certification.
Hope that this address the questions raised in the forum.
Daniel, I don't know that THX certification has a particularly tight requirement on total harmonic distortion. Morever, I own a 743 and its noise (or "hiss") is well within the limits that I have experienced with several other products that are THX-certified, including Denon.
The "hum" that people refer to with the latest batch of NADs is most likely considered as a separate issue from THD, and probably the result of poor isoloation from ground-loop or RF interference.
Daniel Benatar
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Posted on
Darryl Meister,
I am not the THX expert, though; I know that THX ltd is trying to optimize the sound. From what I am reading, is that the movies and music could have many separate sound elements like, sound effects, dialog, music... and all independently recorded and then mixed down to X.1 surround channels. And when all of this translates to home theater there is significant degradation with the sonic quality. With this degradation, THX ltd addressed these issues by establishing a set of standards for manufacturing to ensure accurate as much as possible for movies as well as music playback. One of the thing to achieve this kind of accuracy is to optimized as much as possible the signal to noise ratio without influencing the sound quality as when you trying to reduce the noise, most of the time the companies are using capacitors as I wrote, and these capacitors are using as a filters. And this influence on the sound quality. Of course, that the signal to noise is only one of the elements that need to be optimized in the THX certification.
Now, when you wrote that the hiss from your receiver is identical to other receivers, you need to remember that it's very difficult to measure it by using lad and analytical system. This is way NAD has a difficult time also to understand the problem and have a root cause fix solution for this noise issues. And this is way I am saying that in order to resolve this issue, NAD must have outside auditor like THX that will find the gap, and provide recommendations how to solve it properly with the right procedure for long term.
Actually, I said it was "within." I would say that the hiss from my 743 is actually lower than the hiss produced by the comparable Sony, Onkyo, and Denon receivers I auditioned. It was not quite as low as with the Marantz I auditioned.
The performance (as opposed to processing) requirements most often emphasized with THX certification is the ability to deliver reference-level sound (around 75 dB or so) in a room of specified size (depending upon Select or Ultra), the ability to maintain stable power across down to around 6 ohms with a relatively flat frequency response, and so on.
And keep in mind that filtering noise is different from controlling distortion, which is also affected by the quality of the signal processing.
With regards to the THX certification...I do feel also it would be a beneficial thing for NAD, however, I do feel that if I find a receiver that has everything I want it the sound is excellent, then I won't not buy it because it's not THX certified. I have say...I am leaning towards Rotel for my Paradigm studio 100's...NAD just has me a bit to anxious. Great input by the way.