NAD T763 gain / line-in question

 

As a newbie to NAD I'm quite happy with my new HT receiver. However I have encountered volume issues with it that leave me concerned. Specifically, any given volume setting plays FM radio SIGNIFICANTLY louder than any other source input (DVD and cable TV). My authorized dealer responds, "that's how NADs are made, turn up the gain on the front speakers for better DVD volume." Obviously all this did was increase the volume of all sources, but it did nothing to make them more commensurate, or equal, with one another.

Frankly, I wouldn't find this a big deal if I hadn't been pushing maximum volume (as in +5 and + 10dB on the indicator!) with two or three different DVD's. I realize my DVD player may have a low line out signal and that DVDs can be recorded at different levels. However I'm quite bothered by the discrepancy from FM radio to all other sources ... it's as if the gain from the radio tuner to the "preamp" (for lack of a better word) is set far higher than for other sources. Is this possible?? Is there a remedy?? I love my NAD, but this leaves me frustrated! I'd appreciate any insights!
 

wigglyman
Andy,

I've experienced this same issue with my T762 and have posted about it but got very little response. From what I can gather, it seems to be a NAD attribute, and not a defect. I emailed NAD and their one line response was this: "In DSP modes the gain is lower and hence it will not clip the amps."

With mine, the volume difference between the stereo and surround modes is huge (I haven't tried FM radio). I can't even approach max volume in two channel, but like you, I can turn it all the way up to the +7db limit with DVDs. It's certainly louder than I would normally listen to, but kind of disconcerting that the max volume is actually listenable on a machine that's suppose to have "bags of power."

I heard that in general, DVDs don't play as loud as CDs but you'd still think there would be a little more top end room on the volume dial.

I too love the sound of this unit, and as I don't generally listen to music or movies at ear shattering levels, I don't think I'll return it. I've also seen some posters complaining about the same issue with other brands, so it's not just NAD.
 

Paul T
What speakers are you guys driving?? I have a T752 with Paradigm Studio 20v3's and I thought getting to -19 for loud listening was high on the volume level and -10 which I only tried once was ready to take the pictures off the walls lol... guess I'm still used to the old school where volume controls were a knob with a white line and they always said you should never go past 12 o'clock for that would be pushing amps to distortion levels.... Figured out that actually -34 would be the half way point from 0 to +6 so I guess that old school stuff doesn't apply to new receivers and the way they control the volume levels...
 

wigglyman
Paul,
I'm running B&W 602s which shouldn't be difficult to drive. Yes, getting up to -10db in stereo with a cd is very loud on my receiver as well, but how high can you reasonably push your T752 in surround mode with a dvd? With dvds, I don't hear anything until around -39db and -10db is just a modest listening level.
 

New member
Username: John_a

Post Number: 4
Registered: 12-2003
"dB" is relative, not an absolute measure of anything; add 10 dB and things sound about twice as loud as before. Adding 10 dB is a bit like turning the volume control up though say 30 degrees on an old amp - or 11.30 to say 1 o'clock.

The volume you hear depends on how much gain (roughly equals volume control position) you multiply the input signal by. NAD made the radio tuner as well as the amp and it probably has a good input match for the amplifier.

Power is different from gain, it is the rate at which work is done to drive the load of the speakers. With a weak input signal (try phono...) you may need to turn the volume control right up to +10 dB or more, to get good loud sounds and the right power to the speakers. That's OK. Distortion and bad things do not happen at a fixed gain (dB) value; they happen at close to max power output, however you get there. A really huge input signal can produce distortion at moderate gain, because the thing is pushing out close to max power. A very weak input signal can give good loud and undistorted sounds at very high gain.

I think that dB value on the display is just to give you some idea of how much headroom you have left: it really replaces the the position of the volume control on older amps with analogue signals.

No receiver maker can know all the sources you might want to give to the inputs.

In short, it is only a problem when you can hear it is a problem, for example when either things will never play loud enough or else they sound distorted. The dB value is a comparison with your starting point.

Then there is the level of the recording or broadcast; different recording companies put different levels on discs. It was so even in the days of the LP. That is not a receiver/amp problem, either.

Dynamic range is the difference between the largest and smallest signals on the recording. Classical music and good movies tend to require high dynamic range. Pop/rock music mostly requires little dynamic range, it is close to the largest signal all the time. So DVDs are likely to sound quieter that pop/rock CDs at the same gain setting most of the time: the DVD is keeping a lot of headroom in reserve for the specially loud bits, which are rare.

It is not a brand problem. Except a better amp should give you wider dynamic range capability, and so the difference between difference sources at the same gain control may be more noticeable.
 

New member
Username: Andy

Post Number: 1
Registered: 12-2003
Thank you all very much for your inputs and comments. As I suspected, the different gain for different inputs resulting in different volumes from different sources (sorry) is a real idiosyncrasy of the NAD, even if not truly a problem. I guess other brands have the same issue. Nonetheless, I find it a bit disappointing.

As for what speakers ... I have Martin Logan Aeons, hybrid electrostatic loudspeakers with regular woofer. Needless to say, these are hard to drive and that is one reason I went with NAD in the first place. My dealer assured me his son had the same speakers and NAD unit at home and it worked fine. When I tested my pain threshold with Eric Clapton live DVD I actually had the amplifier turn itself off. Now that scared me. Mind you, there was no evidence of distortion with the speakers, which are rated for 200 watts. However, I changed a few setting and tested again. Again, the unit powered off. At that point I knew I had too little power for these speakers. My solution? A sunfire symphonic reference amplifier, rated for 250 wpc at 8 ohms and 500 wpc at 4 ohms. My speakers can dip below 1 ohm while operating (so I'm told) so I figure the extra overhead of power will be great. Nonetheless, I still managed to get to max volume knob position (indicating +10dB)with Les Miserables DVD. Everything else seems to be plenty loud. I just don't get why NAD would deliberately make the internal gain for DVD, etc, so very different from the internal gain for FM. Boggles my mind!

Again, thanks for all the inputs and help!
Andy
 

New member
Username: Wigglyman

Post Number: 1
Registered: 12-2003
Very informative John...thanks.
 

New member
Username: John_a

Post Number: 7
Registered: 12-2003
wigglyman,

You are welcome. Not sure I made myself clear, though!

You can get the same effect just by choosing different radio channels. Rock/pop will almost always be loud (unless acoustic - e.g. Clapton Unplugged (does it count?); news and current affairs medium; classical music will seem quiet (unless it just happens to be doing the last bit of a Mahler symphony or something).

Andy; Don't be disappointed. The difference in levels is a plus, if anything. Dynamic Range Compression is what makes everything sound the same. It has some uses e.g. in cars but it is definitely the enemy of real hi-fi audio - that is, if you want to hear the most accurate reproduction of the original sound.

That must be a great receiver. I wish I had one...
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