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bounce to disk VS. print new stereo track Virtual Instrument Plugins
Old 16th September 2007
  #31
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Quote:
Originally Posted by masteringhouse View Post
I realize dithering is there in the dithered plug regardless, but my understanding is that each process from 24 to 48 back to a 24 bus invokes a dither process. It's not really completely explained where and when in the white paper from what I've read/understand. By having a "master" fader in the background to me just means that there is some sort of 48 or 56 bit "accumulator" for summing that all of the individual tracks are running through. I would tend to doubt that the processing is exactly the same even if only a visual aid is added to control this "accumulator".
Sorry if this is redundant commentary, but creating a master fader is not an example of a place where any additional "accumulators" are created or any "24-to-48-to-24 bit bus" action is happening. It's not like creating an aux fader, or adding code to the mix engine. The mixer is there in that form already, the master fader is simply a means of changing a coefficient value in the existing 'math'. Same end result as trimming the faders feeding the outputs in question.

Quote:
Originally Posted by masteringhouse View Post
Also the potential issue may have nothing at all to do with dithering or processing the individual channels but in a latency between the two channels by adding a master fader.
What?

Quote:
Originally Posted by masteringhouse View Post
Obviously I'll have to do some testing when I get a break and will post results. I really hope that both you and Matt are right and what I and some of my clients have been hearing is some sort of placebo effect, though blind testing seems to prove otherwise. I would rather that it isn't the case for ease of use and flexibilty, so if anything I'm biased in the opposite direction.
Sure! you should do the tests, so you can cross this off your list of things to worry about.

Quote:
Originally Posted by masteringhouse View Post
Question, for a null test would you recommend:

1. A file with a few 1 sample clicks for lining up the results and removing any potential non-channel latency, followed by pink noise?
I'm still not sure what latency you're thinking about, but if you're gonna use pink noise, I'd print a chunk of it rather than generating it with the signal generator. Or you could just use a stereo file of some music.

Quote:
Originally Posted by masteringhouse View Post
2. Given that dither is random, how is it possible to get any two to null completely if they are processeed in different passes?
you can use the regular stereo mixer too if you really want to. Should be sitting there, lonely, in your "unused plugins folder"

I'll buy you a beer if you find anything.

-dave
Old 17th September 2007
  #32
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Quote:
Originally Posted by MattGray View Post
Editing yes but fades & sequencing are done in WaveBurner at 24bit 44.1kHz... MBIT+ dither using Ozone3 as a master insert in WaveBurner.
Hey matt:

I was just reading this old thread and didn't realize a) that Ozone3 was available for Mac and b) didn't know it could be used in WaveBurner!

I do have WE but prefer to do my sequencing, some fades and the occasional volume adjustment in WB. So that means leaving files at 24b. If I bought Ozone, that would at least give me an alternative to POW-r dither, not that I really have any complaints with it.

I guess the other avantage in having Ozone would be that I would have an alternative to the L2 and TC Brickwall in Pro Tools.
Old 17th September 2007
  #33
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One unfortunate thing about Pro Tools HD is that one needs to know to substitute the dithered mixer for the non-dithered default mixer in the plug-ins folder.
Old 17th September 2007
  #34
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Quote:
Originally Posted by dave-G View Post
>>Also the potential issue may have nothing at all to do with dithering or processing the individual channels but in a latency between the two channels by adding a master fader.

What?
One side being slightly out of phase with the other due to latency during processing. ¿Comprende?

Quote:
Originally Posted by dave-G View Post
Sure! you should do the tests, so you can cross this off your list of things to worry about.
No worries, I don't use a master fader. Probably still won't even if the tests prove that there are no issues. No need to in mastering if you set levels properly. Mixing is a whole other bags of worms.

Quote:
Originally Posted by dave-G View Post
I'll buy you a beer if you find anything.
I sincerely hope that tests prove otherwise, but if not I've been drinking Stella Artois this week.
Old 17th September 2007
  #35
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Quote:
Originally Posted by Bob Olhsson View Post
One unfortunate thing about Pro Tools HD is that one needs to know to substitute the dithered mixer for the non-dithered default mixer in the plug-ins folder.
I'm using PTs to play a mix, run it out to an analog chain (with outboard digital gear inserted here and there) and recording back in through an insert. At the most, I will use one plug-in (MDW EQ) but not often.

Would using the dithered mixer or the non-dithered default mixer have any effect when using PTs as outlined above?
Old 17th September 2007
  #36
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Quote:
Originally Posted by Andy Krehm View Post
...Would using the dithered mixer or the non-dithered default mixer have any effect when using PTs as outlined above?
I'd use the dithered mixer.
Old 17th September 2007
  #37
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Quote:
Originally Posted by Andy Krehm View Post
I'm using PTs to play a mix, run it out to an analog chain (with outboard digital gear inserted here and there) and recording back in through an insert. At the most, I will use one plug-in (MDW EQ) but not often.

Would using the dithered mixer or the non-dithered default mixer have any effect when using PTs as outlined above?
Not really Andy the only time the 'dithered mixer' comes into play is just before a physical output assignment in Pro Tools. You wouldn't benefit from it if you didn't change gain anywhere & there is no benefit to using the 'Dithered Mixer' with plug-ins.

Unfortunately Digi didn't take into account the plug-in bus architecture in HD which goes back & forth from 24-48-24bit in TDM world or 24-32float-24 or 24-64float-24bit in RTAS world. Whenever a plug-in is inserted, it's going up & down most times without dither (unless it's built into the plug-in).

Rumour has it that Digi is planning to release some new TDM hardware at AES & I bet they've fixed some of the plug-in precision under the hood. Not that I buy into rumours, but I've got some pretty reliable sources.

M
Old 18th September 2007
  #38
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I find a digital volume control before a D to A that feeds an analog device can come in very handy. I also can't remotely imagine being able to hear any negative effect from using 24 bit dither.
Old 18th September 2007
  #39
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Quote:
Originally Posted by Bob Olhsson View Post
I find a digital volume control before a D to A that feeds an analog device can come in very handy. I also can't remotely imagine being able to hear any negative effect from using 24 bit dither.
Ah, I was wondering what was behind your recommendation.

I don't use PTs to control volume any more but instead use one of my TC 6000 modules to do gain staging before the DAC.
Old 18th September 2007
  #40
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I automate levels of the source track (along with plug settings). Handy for being able to listen to the entire CD at once before bouncing if there are no or minor changes to the analog chain. Another potential reason to use the dithered mixer.

BTW I've run a few null tests, mostly to check the phase relationship between L&R chanels with and without a maser fader. So far everything seems to be coming up clean, though I noticed a few other oddities not having to do with the discussion above.

For example, if you send a mono signal to a stereo aux track, reverse the polarity on one side, then send this out in mono to another aux track (to null the two channels) with a master fader, the level does not go down to infinity (this is on a dithered mixer so it may make sense). However the peak level indicator shows two different levels on the master fader and the secondary aux track with the master fader being far lower than the aux track. I would have expected these to be the same, at least very close in the numbers showing up.

There is also an issue when inserting a signal generator in an aux track (has to be done as RTAS multiple mono as far as I can tell the built-in generator isn't an option otherwise). When reversing the polarity on one side and feeding this out in mono it doesn't null. You have to delay one side by 12 samples in a 96K session to get it to work correctly.

If anyone is interested, I'll make these session files available for download. If no one responds I'll assume it's for my own "enjoyment".
Old 18th September 2007
  #41
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Hey everybody, i'm new here, my first post. This topic I have rangeled with for a long time now. After posting on other forums about this, this being "Why Does The 2 Track Print Not Sound As Good As The Mix?"

I have heard this as well, with BTD, I seemed to have lost something. it's not as clear, the imaging is somewhat skewed, a loss in defination and detail from the mix before BTD. Theroy aside, it just does not sound the same to me.

Then asking old timers from the ol analog days and they would say, it's a given the 2 track print never sounds as goods as the mix off the board.

Ok, that's cool but not exceptable to me! So I did a lot of experementing of different ways to print in PTHD. What gave me the best result was setting up 2 mono tracks, assigning all outputs to the AES (enc) output, taking a high end 1 meter AES cable from the 192K right back into the AES input.

Assign the output of those 2 mono tracks to AES 15/16 out and running that into my D-A converter. Then print the mix to 2 mono tracks instead of 1 stereo track. For whatever reason it sounded wider than a stereo track.

Doing it this way sounded much closer to the original mix than other methods. One other thing I found is a master fader seems to degrade the sound. I noticed this in both DP and now in PT.

I also master as dual mono instead of stereo. Once the master is done, then save as stereo.
Old 18th September 2007
  #42
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Quote:
Originally Posted by Jazzmo View Post
Hey everybody, i'm new here, my first post. This topic I have rangeled with for a long time now. After posting on other forums about this, this being "Why Does The 2 Track Print Not Sound As Good As The Mix?"

I have heard this as well, with BTD, I seemed to have lost something. it's not as clear, the imaging is somewhat skewed, a loss in defination and detail from the mix before BTD. Theroy aside, it just does not sound the same to me.

Then asking old timers from the ol analog days and they would say, it's a given the 2 track print never sounds as goods as the mix off the board.

Ok, that's cool but not exceptable to me! So I did a lot of experementing of different ways to print in PTHD. What gave me the best result was setting up 2 mono tracks, assigning all outputs to the AES (enc) output, taking a high end 1 meter AES cable from the 192K right back into the AES input.

Assign the output of those 2 mono tracks to AES 15/16 out and running that into my D-A converter. Then print the mix to 2 mono tracks instead of 1 stereo track. For whatever reason it sounded wider than a stereo track.

Doing it this way sounded much closer to the original mix than other methods. One other thing I found is a master fader seems to degrade the sound. I noticed this in both DP and now in PT.

I also master as dual mono instead of stereo. Once the master is done, then save as stereo.
Nice theories, but what method/s of testing did you use to back up these claims besides your ears? Did you do a null test between your print method & a BTD? Did you do a null test between a mixdown with a master fader & one without?
Old 18th September 2007
  #43
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Quote:
Originally Posted by MattGray View Post
Nice theories, but what method/s of testing did you use to back up these claims besides your ears? Did you do a null test between your print method & a BTD? Did you do a null test between a mixdown with a master fader & one without?
Also checking the above by "stress testing" the session. Will a CPU constrained session sound the same as one that isn't? There are lots of variables here.

Does anyone know the rules regarding when PT invokes its pan law? Would the simple act of panning or summing two mono tracks suggest that dithering might be needed due to an automatic level change?
Old 18th September 2007
  #44
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Quote:
Originally Posted by Bob Olhsson View Post
I find a digital volume control before a D to A that feeds an analog device can come in very handy. I also can't remotely imagine being able to hear any negative effect from using 24 bit dither.
Same here Bob, I use my Z-Qualizer as a digital volume control just before the DAC.

I usually prefer the sound of it with 24 bit dither "off".

Call me a rebel.

Quote:
Originally Posted by Jazzmo View Post
asking old timers from the ol analog days and they would say, it's a given the 2 track print never sounds as goods as the mix off the board.
That's why Mastering was invented !

JT
Old 18th September 2007
  #45
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Quote:
Originally Posted by masteringhouse View Post
Does anyone know the rules regarding when PT invokes its pan law? Would the simple act of panning or summing two mono tracks suggest that dithering might be needed due to an automatic level change?
Any time you're not hard-panned L or R. Easy to see an example when you've got something mono center-panned. ie: if you have a mono track sending a -20dBFS tone panned up the middle to a stereo bus or stereo master/outputs, it will be received by that bus/outputs at -22.5dBFS, following a taper back up to -20 as you pan it to one side or the other.

The B-side of your question makes me want that beer!

-dave
Old 19th September 2007
  #46
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It's not a theory when you can hear the difference. What I did to become convinced is BTD a mix, then RTD in the way I described, assigning all outputs the the AES 1/2 enclosed then wiring that right back into the AES 1/2 Input on the 192K.

Recorded the mix as 2 mono tracks panned r/l of course. Import the BTD mix, set that up on a stereo track and mute between them in real time at the exact point in the song. The difference was obvious, the RTD mix was wider, had more detail, everything sat in the mix better where as the BTD mix sounded somewhat skewed in comparison.

Theory aside, i've never been happy with BTD. Give it a try! What do you got to lose?
Old 19th September 2007
  #47
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Quote:
Originally Posted by dave-G View Post

The B-side of your question makes me want that beer!

-dave
Question or no question I want a beer
Old 19th September 2007
  #48
Mastering
 

Quote:
Originally Posted by Jazzmo View Post
It's not a theory when you can hear the difference. What I did to become convinced is BTD a mix, then RTD in the way I described, assigning all outputs the the AES 1/2 enclosed then wiring that right back into the AES 1/2 Input on the 192K.

Recorded the mix as 2 mono tracks panned r/l of course. Import the BTD mix, set that up on a stereo track and mute between them in real time at the exact point in the song. The difference was obvious, the RTD mix was wider, had more detail, everything sat in the mix better where as the BTD mix sounded somewhat skewed in comparison.

Theory aside, i've never been happy with BTD. Give it a try! What do you got to lose?
Jazzmo, I'm not going to question your method, but your results do go against my own listening and measurements. Did you also test for a null? Was there a measurable difference?

BK
Old 19th September 2007
  #49
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Quote:
Originally Posted by bob katz View Post
Jazzmo, I'm not going to question your method, but your results do go against my own listening and measurements. Did you also test for a null? Was there a measurable difference?

BK
Bob -

Could you explain your methodology when you you tested, it may save me some time. Such as:
  • Did you use a dithered or non-dithered mixer
  • Was this on LE or an HD system (32 vs 24 question)
  • Did you try both bouncing/recording to track in a highly loaded session versus one with low cpu usage
  • What did you use as a source track for comparison
  • What sample rate(s) did you use for the session
  • Were you using an internal or external clock
  • Any other parameters that you feel might be relevent

Thanks!
T
Old 19th September 2007
  #50
Mastering
 

[QUOTE=masteringhouse;1507809]Bob -

Could you explain your methodology when you you tested, it may save me some time. Such as:
  • Did you use a dithered or non-dithered mixer
  • Was this on LE or an HD system (32 vs 24 question)
  • Did you try both bouncing/recording to track in a highly loaded session versus one with low cpu usage
  • What did you use as a source track for comparison
  • What sample rate(s) did you use for the session
  • Were you using an internal or external clock
  • Any other parameters that you feel might be relevent

Actually, since all I currently own is Pro Tools LE, all my listening tests have been based
on comparative files supplied to me by clients working in (at the time) Pro Tools TDM version 6 or so....submitting files for mastering... auditioned and tested by me in SADiE with either the Benchmark DAC or the Cranesong Avocet DAC, SADiE on internal clock at all times. In some cases they've sent me 3 files, in others only 2. In all cases so far, they have nulled out AND (naturally) sounded identical.

It's been a while since any clients have sent me comparative files so I am not privy to the effects of version 7. We are probably going to be installing Pro Tools HD for mixing in Studio B so you can be sure I'll do some more of our own testing there as well.

BK
Old 19th September 2007
  #51
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It's seems like we may chasing the aural version of UFOs here.

Anyway, Bob can you think of any reason why the monitoring side of the equation in PT may be causing this? In other words, the digital streams are identical, but when routing within PT there are some differences that may be causing these effects? PLL, jitter, etc. for instance?

Since your tests were done in SADiE you would not have been hearing this.
Old 19th September 2007
  #52
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Thanks Bob, but it seems like you havn't done the exact type of comparison I have using the same gear, such as a big ben as wc master for the 192Kdigital, PTHD (being the core and acell cards), and RTD digitaly using a tara labs 1 meter AES cable.

I don't have the in depth understanding of digital theory like you do, so I can't really understand your perspective. All I know is what I hear. You may not like this but I'm using a set of Genelecs and subwoffer. The signal path is very short, another words I come out of the 192K using an AES cable going directly into an Apogee D-A converter, directly into the Gens.

So it's a very clean, pure monitoring signal path. I don't have it running thru a board analog or digital. Actualy I use a command 8 for the PT rig.

All I can suggest is for those who are using this type of setup, try it for yourself. It's the closest to the origial mix I have heard. Soloing the 2 track then listening to the entire mix off the same session, there is little to no change.
Old 20th September 2007
  #53
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Quote:
Originally Posted by masteringhouse View Post
It's seems like we may chasing the aural version of UFOs here.

Anyway, Bob can you think of any reason why the monitoring side of the equation in PT may be causing this?
I can come up with some very far-fetched possible explanations for why the two listens might seem different but actually be identical, but I'm NOT going to stretch it that far.

As long as the clocking and monitoring are identical for both listens, then it is not a variable, eh?

We didn't ask if it's an "in the box" mix. Because if it contains any kind of D/A/D path it does make it necessary to examine if that aspect added another variable (doubtful but something to consider).

And finally, while I'd like to believe the poster, I would have to ask him to send me his two or three files for me to compare. And if they are truly different (as well as measure different), find out WHY!


Take care,


Bob

In other words, the digital streams are identical, but when routing within PT there are some differences that may be causing these effects? PLL, jitter, etc. for instance?

Since your tests were done in SADiE you would not have been hearing this.[/QUOTE]
Old 20th September 2007
  #54
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Bob, I well do that!!! I'll do a BTD, and RTD, send it to you on a data CD.

I have your mastering CD demo, i'll look for a mailing address on it, if not look you up on line for it. Expect it in the mail in the next week. COOL!!!heh
Old 20th September 2007
  #55
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Is there anyway I can post the mixes on here? A BTD verses RTD? The file isn't that large.
Old 20th September 2007
  #56
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Quote:
Originally Posted by bob katz View Post
I can come up with some very far-fetched possible explanations for why the two listens might seem different but actually be identical, but I'm NOT going to stretch it that far.

As long as the clocking and monitoring are identical for both listens, then it is not a variable, eh?
Given the same signal path, sure. I think your comment was directed more at comparing BTD versus RTD? Assuming as you mentioned that there isn't an additional conversion (RTD using a bus and BTD using a the same bus) I agree that there should be no difference between the two if using the same clock and monitoring path. I was thinking more in terms of a real time comparison of a source using and not using a master fader. I believe this isn't quite as black and white though the digi white paper says they are the same thing. But then I'm often skeptical of white papers published by the company selling the product, Digi or otherwise.
Old 20th September 2007
  #57
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Quote:
Originally Posted by masteringhouse View Post
I automate levels of the source track (along with plug settings). Handy for being able to listen to the entire CD at once before bouncing if there are no or minor changes to the analog chain. Another potential reason to use the dithered mixer.

BTW I've run a few null tests, mostly to check the phase relationship between L&R chanels with and without a maser fader. So far everything seems to be coming up clean, though I noticed a few other oddities not having to do with the discussion above.

For example, if you send a mono signal to a stereo aux track, reverse the polarity on one side, then send this out in mono to another aux track (to null the two channels) with a master fader, the level does not go down to infinity (this is on a dithered mixer so it may make sense). However the peak level indicator shows two different levels on the master fader and the secondary aux track with the master fader being far lower than the aux track. I would have expected these to be the same, at least very close in the numbers showing up.

There is also an issue when inserting a signal generator in an aux track (has to be done as RTAS multiple mono as far as I can tell the built-in generator isn't an option otherwise). When reversing the polarity on one side and feeding this out in mono it doesn't null. You have to delay one side by 12 samples in a 96K session to get it to work correctly.

If anyone is interested, I'll make these session files available for download. If no one responds I'll assume it's for my own "enjoyment".
what are you sending from the signal generator plug?
Old 20th September 2007
  #58
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Quote:
Originally Posted by toolskid View Post
what are you sending from the signal generator plug?
If memory serves (I've been changing settings around testing different scenarios) it was 1K sine wave a -14dBFS. It should do the same regardless of what is sent out though. To make the adjustment(s) such as polarity reversal and sample delays I've been using the time adjuster plug.
Old 21st September 2007
  #59
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Hey Bob, and all, here's 2 mixes, not going to say which is which, but one is BTD and the other RTD. It's a premaster version. The only difference between the 2 is one is BTD, the other RTD in PTHD.

I know i'm new here and you guys don't know we from a tomato, or is it toomautoo? Anyway I love this website, you guys speecck eerr maah raanguuageee!

Ok I have a link to my site err it goess

Mix 1 www.puresoundstudio.com/SAIL1.mp3
Mix 2 www.puresoundstudio.com/SAIL2.mp3

It's the exact same mix, BTD verses RTD. You may not like the mix but listen to the suttle differences between the 2.
Old 21st September 2007
  #60
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just bumpin' it up....i'm curious.
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