There was a discussion, (or a comment), about this a while back but I can't find it.  Melodyne will increase the level of an audio clip by +3dB when you render it.  Some folks had not seen this but it has happened to me, (every time), going back as least as far as Editor.  I typically only work with mono audio but tonight I was editing a stereo piano track and on render, Melodyne DID NOT increase the level!  Very interesting.
 
Just an FYI.
 
 

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I have seen this issue right after Melodyne was first bundled. I have upgraded to Melodyne Studio since and have not had the chance to do much with it lately so I don't know if the issue still occurs.
 
Several posts have reported this issue.
Here are a few links. The last one offers a possible explanation.
http://forum.cakewalk.com/FindPost/3331132
http://forum.cakewalk.com/FindPost/3209196
http://forum.cakewalk.com/FindPost/3081812

microapp
I have seen this right after Melodyne was first bundled. I have upgraded to Melodyne Studio since and have not had the chance to do much with it lately.
 
Several posts have reported this issue.
Here are a few links. The last one offers a possible explanation.
http://forum.cakewalk.com/FindPost/3331132
http://forum.cakewalk.com/FindPost/3209196
http://forum.cakewalk.com/FindPost/3081812

Thanks Michael.  I knew those posts were out there but could not find them.  Yep, Melodyne has done the 'boost level by 3dB' thing for me since at least Editor and has continued with Studio.  It's become part of my process now, lower the output of Melodyne by 3dB before rendering the clip. 
 
What's interesting is that when editing a stereo clip in Melodyne, the volume knob was de-activated but the rendered levels were correct!  I should contact Celemony about this again.

This drove me nuts when I encountered it and I tried everything I could think of to fix it. Like you, I gave up and just worked around it. I assumed it would be fixed (or at least explained) at some point.
Let us know what Celemony says.

I spent last night editing audio clips with Melodyne Studio.  The 3dB volume increase issue now seems to be fixed in the latest patch, (4.1.0.001).  I had hesitated to install it judging by all the difficulties other folks were having.  After I built my new machine and reinstalling Studio, (the new patch), it seems to now work!  The new interface is giving me fits but I'll get used to it.
 
AT LAST!  I no longer have to adjust the output gain in Melodyne Studio before rendering a clip.  Thank you Celemony!
 
Anyone else notice this?
 
Paul

There's a version 4.1.0.001 of Melodyne Studio...

bvideo
There's a version 4.1.0.001 of Melodyne Studio...

What he said.  Thanks Bill.

You're welcome. I was impressed with the multitrack display and editing. I hope it's stable for everyone.