Gearslutz.com - View Single Post - Is Digital Performer Audio and/or Summing Broken?

grimepoch · 28th February 2008

Exactly how is it flawed? Your argument makes absolutely no sense. Obviously if you add plugins and changed and write out two different audio projects and you bring them together and do the null test, if they do not null each other out, like you've said, then THERE IS A DIFFERENCE. That's the whole point!

Let's be clear, the question here was about the SUMMING part of the DAW. Not the handling of gain, panning, plugins or anything else. There are other parts of the DAWs that are different, and no one is arguing that. I spent a long time demonstrating on graphs about the pan differences between Logic and DP and, as I said, creating a plugin for those that wanted to create their own pan curves.

My test CLEARLY and CONCISELY shows that between Logic and DP, the summing engine works IDENTICAL. They both use 32-bit float and they both have used 32-bit float for a long time. Just like almost all other total in-the-box DAWs. As long as we've used 32-bit computers we've had 32-floats and there has never been a reason NOT to use 32-bit so you get the power of the FPU.

Even further, I surmise that if the summation of signals on the mix bus is less than 24-bit, as most do since they are never in the red, that even with an HD system you are going to see the same results. We are within the resolution. Where I am VERY curious is when the mix bus peaks, I want to see if with the HD if the values are different around that point.

Note however, this is NOT an argument that 32-bit is more accurate than 48 bit INT because we know it's not, especially things for low pass filters. There are many white papers on this topic and it's pretty clear that negatives of floats are a lot higher than ints at these sizes. The ints do not deal with all the same round-off issues. Again, I am only curious in the summing.

And as a final thought, I have NO doubt that since the summing is the same between DP and Logic that effects will be the same since they both use the AU protocol and they both use the same internal data structure.

28th February 2008	#123
grimepoch Gear Head Joined: Sep 2007 Location: Raleigh, NC Posts: 69	Exactly how is it flawed? Your argument makes absolutely no sense. Obviously if you add plugins and changed and write out two different audio projects and you bring them together and do the null test, if they do not null each other out, like you've said, then THERE IS A DIFFERENCE. That's the whole point! Let's be clear, the question here was about the SUMMING part of the DAW. Not the handling of gain, panning, plugins or anything else. There are other parts of the DAWs that are different, and no one is arguing that. I spent a long time demonstrating on graphs about the pan differences between Logic and DP and, as I said, creating a plugin for those that wanted to create their own pan curves. My test CLEARLY and CONCISELY shows that between Logic and DP, the summing engine works IDENTICAL. They both use 32-bit float and they both have used 32-bit float for a long time. Just like almost all other total in-the-box DAWs. As long as we've used 32-bit computers we've had 32-floats and there has never been a reason NOT to use 32-bit so you get the power of the FPU. Even further, I surmise that if the summation of signals on the mix bus is less than 24-bit, as most do since they are never in the red, that even with an HD system you are going to see the same results. We are within the resolution. Where I am VERY curious is when the mix bus peaks, I want to see if with the HD if the values are different around that point. Note however, this is NOT an argument that 32-bit is more accurate than 48 bit INT because we know it's not, especially things for low pass filters. There are many white papers on this topic and it's pretty clear that negatives of floats are a lot higher than ints at these sizes. The ints do not deal with all the same round-off issues. Again, I am only curious in the summing. And as a final thought, I have NO doubt that since the summing is the same between DP and Logic that effects will be the same since they both use the AU protocol and they both use the same internal data structure.