API 7800 Master as summing bus for 888's

[Baixo]

Thanks to blairl for good and very valid information and comments. I, too, have mixed in Pro Tools with very respectable results, but I haven't had the same luck with everything. I do think the monitoring system/room design will (as Roger says) make any mix you do on that system sound better than others.

I, like many of us, am not a complete unbeliever in PT's mixing capabilities. After working for a week mixing a project in PT, I started a new project in a small studio with excellent room design. I had a day off and threw up the old sessions in there, to compare the mixes (that were done elsewhere). I did some rough mixes in that room (an hour a piece, through a desk) that were far superior to the ones I did previously. Is it the room? I know that All the plug-in EQ I needed became unnecessary going through the desk, and the 1073 EQs, when needed, yielded a better tone. I cut down my need for EQ by 2/3.

Now, had I NOT gone direct outs mode into the desk and just did it directly in PT in the nice room, would I have noticed/cared about the difference? I honestly can't say. I'd like to think it would've solved the problem of the original mixes. I do know what I heard, however, and it worked in this situation anyway.

I don't get a lot of time to do A/B comparisons that do justice to either party. I can only rely on what I learn from experience. If time and money weren't an issue, I'd experiment more on my client's dime, but that can't happen.

I WANT to mix in Pro Tools. I like resettability and automation! Perhaps the money one would spend on doing it in a great room seems wasted by not using the desk...

[blairl]

Originally posted by Tom N:
blairl,

I run Pro-tools through a V3 and mixes always sound better and not as thin. Roger Nichols ..........last CD he mixed? Doesn't he write for mix mag and his word is gospel? Don't you just love the sound of MP3's? Well, Roger Nichols says....he also has stock in the company....

If your so smart... why do 90% mix through a console and why are people recording in pro-tools then dumping to a 24 track and mix from a analog console? Maybe there not listening to you or Rogers Propoganda:
I HAVE MY OWN MIND AND MY OWN OPINION!!!!!!!!!! Good sales pitch for DIGI........

If you read my post carefully you will see that I understand that people have their own opinions and that some people just like the sound of analog consoles. I was just offering an alternate view. In the end people should decide for themselves what sounds best for them. Roger Nichols was only one of several people that I quoted. There were several opinions. I don't want people to take my word or your word as what SHOULD be done. Everyone should listen for themselves. I'm just posting and alternate view. No offense intended to anyone.

[Baixo]

Blairl wrote:

Every time a signal is doubled the level will rise by 3 db, so for a 64 track session running out to an analog console the quantization noise floor will be at -126 dbFS instead of -144 dbFS if you were to mix within Pro Tools. Granted -126 dbFS is also way down there, but people seem to be afraid that the more channels used in Pro Tools, the worse it sounds. I'm just saying that this cumulative quantization distortion that may be affecting the sound is actually worse if you use direct out mode to an external analog or digital console than if you were to just use the interal Pro Tools mixer.

Using both "Noise" and "Distortion" interchangeably to both speak about Quantization Error can be confusing.

Since quantization error is, in fact, distortion and not noise ("quantization noise" as a phrase or concept has no meaning) because quantization error is *correlated*, how can it build up cumulatively? Noise, is by definition, uncorrellated, thereby making it possible to add in such a way. This just occurred to me after reading your post because the error can't really be doubled (or more) in the strictest sense because it's different for each signal. Or can it?

I'm not being critical of your post at all, I'm more interested in learned discourse. In light of the above, how does this affect the QD issues in the PT Mix Bus?

[Baixo]

Here's another one for you who remember the great "Pro Tools Sound Quality???" post of yesteryear:

Does Mixer B work under 5.1?

This discussion has got me thinking up ways to experiment with this issue in a way that all other factors will be equal (room, monitoring etc.).

[blairl]

You're right, let's put it this way: Quantization error causes distortion; at the 24 bit level this distortion is audible at about -144 dbFS. Quantization distortion is not the same as something like white noise. If you boost the signal high enough to hear it you'll notice that it is completely dependent on the source material and is corelated with the source material from each individual track. If you use direct out mode then the distortion from each output will be uncorelated with the distortion from every other output, so in this sense it is uncorelated. However, the distortion is all over the place and not constant like white noise for example, so there's no real way of measuring it consistently. At certain points in the song it is exactly the same as other signals so it can be cumulative. The actual sound of the distortion is the same for each source, but it is happening at different times in different places depending on the original source so the cumulitive level is constantly varying. The 3 db for every signal doubling is a general rule for constant noise. This is my understanding anyway.

[This message has been edited by blairl (edited April 12, 2001).]

[blairl]

I haven't installed 5.1 yet. Is it a fact then that Mixer B will not work with 5.1? If not then I hope that digi will consider making a dithering mixer available.

I have coresponded in great length with Paul Frindle one of the main designers of the Sony Oxford about dither in a digital console as well as Stanley Lipschitz the father of DSP, and could offer some legitimate reasons to do this in the PT mixer. Is anyone at digidesign interested in hearing this point of view? If you don't want to discuss it here you can e-mail me.

[Dead Space]

blairl,

I can't speak for Digi, but I know that I, as well others, would like to hear what you have learned.

Share your info here. Public knowledge and opinion seem to be very effective in eliciting a response from the powers that be.

[Haddock]

Another option is to purchase one or more AMEK driver in a box units. Each unit takes up one rack space and can be wired to sum all the channels to a stereo bus. However, each unit is about 3 grand, and gives you 8 channels to work with. You can purchase as many of these units as you like to expand the number of input channels you can sum.

[Jules]

I still belive 4 x 4 mic pre units from API (3421M) with the mixer option could be summed to one stereo out..
patch bay could come into play somehow with inserts???
That might rock!
Jules