Gain Setting impact on AV processor DSP Quality?

@emergingsoul if the NAD’s DSP took room measurements (e.g. a frequency sweep) typically it captures both amplitude and phase for any particular frequency. It adjusts the gain to flatten the response, and attempts to apply the proper phasing fixes so that sound in the room doesn’t cancel each other out or amplify each other and instead hits your ears with improved timing at the amplitude it was meant to be heard. The two work hand in hand to deliver the end result you are experiencing. 

@blisshifi

Awesome comment actually learned a few things. A lot more going on Beyond just comparing curves I guess. Although do the curves in themselves highlight these things in anyway. The timing between speakers which I guess is influenced by very precise measurements which I see in the settings Post DSP measurements and maybe this is very effective.  The Rockettes do a great job performing without phasing and just a few out of phase rockettes would really screw things up.

Your system definitely reflects isolationism. I take interest in your diffuser panel behind your system although mine is a TV screen so it wouldn’t work for me. The cylindrical bass traps in the corner are cool, not sure I understand the sound reducer panels which I’ve never seen before and curious to know what they bring to the picture. The white rug is awfully scary.

Thanks for the info

@emergingsoul You definitely have to look at gain and phase together. For example, if at a certain frequency, say 100Hz (audible bass tone) hits your ear at double the amplitude (gain) at the same exact phase, then you might hear that tone twice or even exponentially as loud (every 3dB is a 50% perceived increase in volume). If your speaker configurations, placements, and room reflections result in multiple deliveries of 100Hz in a way where they arrive completely out of phase, then in theory it would completely null the sound and you wouldn’t hear anything.

The phase of the waveform is similar to a delay. If you think of the waveform as a sine wave, it depends on when the sound is emitted and what part of the waveform it starts from.

It is also important to remember why “frequencies” are called what they are. A 20Hz wavelength, for example requires 60ft to complete one wave. As you double each number (40Hz, 80Hz, 160Hz, etc) the frequency doubles, so in theory if perfectly timed, a 20Hz tone and a 40Hz tone intersect for the every other 40Hz’s waveform. The size and strength of bass notes, and the challenges of managing them, are the reasons for most room mode (boom) and null issues. Not only does it murk up the sound in the bass region, but it interferes with the sound across the whole frequency spectrum, all the way to the upper treble.

You’ll notice that I mention “in theory” often. This is because speaker and electronics designs are never perfect. The room is never perfect. And DSP is not perfect. There’s no way to perfectly address the combination of phase and amplitude for every frequency across the spectrum, but the technology does get better and better.

In the past, while DSP could address some of these things well, I always found DSP to impart digital noise, glare, hash (call it what you want), which inhibited it from sounding analog. Modern solutions have certainly made headway into delivering a higher quality of sonic presentation. For example, I’ve been experimenting with the BACCH DSP for a month now and it is by far the best solution I’ve come across in the market to address both crosstalk and room correction. I’m still looking for a few ways to improve its sonic delivery, but I am confident I will figure it out and in the long run digital glare will no longer be an issue.

As for your comments on my treatments, I am in the camp that the appropriate, tasteful treatments can be the first step in correction, especially before DSP is applied. The better shape the room is in as baseline to start, the less radical the DSP has to be to take it further, should one choose to employ DSP.

I hope this helps.

@blisshifi 

Thank you for another awesome response.

Are you equating gain with volume?  

I always view gain and volume separate but many people tend to say gain when they mean volume.

To be precise, what I mean by gain is amplitude. :)

So what you mean is volume is changed when the amplitude changes.

I always thought gain was different from volume. It's more of a voltage change to the signal which leads to distortion if you increase it too much.

Lots of people confuse gain and volume, it's really not the same thing. But then what do I know I'm just a dumb CPA.