Bounce to Disk vs. realtime mix

[Steve Moore]

Is it my imagination or does a bounce to disk mix sound different than one done in real time?

[vocalvoodoo]

I think you're right man. My bounces NEVER sound the same as the actual session playing back. Matter of a fact, the bounces don't sound nearly as good to me.

[soundsurfr]

If you're bouncing a 24 bit,48KHz session to 16 bit, 44.1KHz, darn right it's gonna sound different. Have you tried adding dither? It's in the plug-ins. Patch it into your master channel.

[jtplayer]

One thing I've noticed is when I play my bounces back via Windows Media Player it sounds different. When this first started happening I just assumed that there was some kind of problem during the bounce. Then one day I was watching the groovy visualizations when it occured to me that maybe that was the problem. I opened the song in Quick Time and it sounded exactly like the playback in Pro Tools.

Everything I've ever bounced and burned to cd has always sounded just like it did when I mixed it. I've been very pleased with the sound quality. I used a VS-880 in the past and nothing I ever did on that rig ever sounded right when it went to cd.

Anyway, that's been my experience.

JT [img]images/icons/cool.gif[/img]

[jtplayer]

Another thing I noticed is that after I got my second hard drive dedicated to my audio, and I bounced from the audio drive to the system drive, everything sounded goofy. I posted here and was advised to bounce to the audio drive. After that everything sounded really good.

JT [img]images/icons/cool.gif[/img]

[Steve Moore]

Nope. Not even trying to dither yet...

[JMS40]

Hi Steve-
Sorry to be repetitive if you've already seen this, but Digi makes a strong argument for always using dither when bouncing.

From the Reference Guide:
You should use the Dither Plug-In when mastering to a 16-bit file with the Bounce To Disk command, or when mastering to an external device that records at 16-bit. This is even when using 16-bit sessions.
Even though 16-bit sessions use 16-bit files, they are still being processed internally at a higher bit rate:
-32-bit floating for Pro Tools LE systems.
For this reason, whether you are using a 16-bit session or a 24-bit session, it is reccomended that you use the Dither Plug-In when mastering to 16-bits"

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[vocalvoodoo]

So that means if I'm using Waves Ultramaximizer+, I'm doind that right? (dithering)

[Steve Moore]

Perhaps I didn't make myself clear... I am not at the mastering stage here. I'm just dumping two track rough mixes...

I understand that the tracks must become 16 bit for cd playback. But I'm not talking about dither loss/differences here.

My original intent was to suggest that for some reason a bounce to disk (w/ no dithering) sounded different than passing the same output back to two tracks and tracking in real time.

Does this make sense? I am sure there is a simple explanation.

The signal stays in the digital domain DIGI multi ADAT out to board and out the 2 channel SPDIF back into the digi-PT.

So it either has to do with the bounce to disk process or the SPDIF. Could the board's SPDIF be altering the signal in any way. Could it be assuming 16bit? Are all spdifs 16 bit? How cab I verify that the same 24 bit signal is returning into PT?

AHA! I solved my own problem while writing this post! The board was configured on the spdif page to 24bit dither (not 16). I turned dither to OFF and wala!

Why would you dither a 24bit signal with 24bit dithering though? How can that be? The options are 16, 20 , 24 and OFF. It seems as though applying a 24bit dither to a 24 bit signal is degrading it. I'm confused.

[marcusb]

First off it's very easy to test if a bounce to disc vs. output and record from a buss. You can just null-test the two versions.

1) bounce your two versions - one using bounce to disc, the second recorded off a buss

2) create a new session with two stereo audio tracks

3) put your two mixes on each stereo track

4) on one of the stereo tracks insert a 1 band EQ and flip the polarity of both left + right channels

Now in theory if both mixes are identical they should cancel perfectly (ie. mix 2 being an polarity reversed version of the mix 1) if they don't then there is a difference between the two methods.

If you are going to try this test be VERY careful of your routing etc to make sure you are actually recording what will be bounced (ie. no plugs on the master fader, no master fader automation).

Secondly, some of you mention that it sounds different when played through Windows Media Player or the Quicktime player. I assume the output of these applications is going thru the 001 and NOT another soundcard. If you are comparing a mix out of ProTools to a mix playing out some ****eblaster of course it will sound different [img]images/icons/wink.gif[/img]

Cheers,
Marcus