Weird Midi/Audio Gremlin

[JamPro]

Hello.  I am using the latest update of CWbBL, in Win 7.

I am having a weird distortion problem in a project.  The distortion appears in an audio clip in an audio track in a project that contains 8 audio tracks.  The distortion occurs at one specific point in this audio clip that is 30-40 secs in length.  The distortion occurs at meas. 96, beat 2.5 - there is no distortion anywhere else in that audio clip except at meas 96, beat 2.5.  At that location, the CW meters show the audio to be more than 10 db below 0 dbFS (so the distortion is NOT due to audio clipping).

I created this audio clip by first recording a midi track to drive a sound module (Roland rd-2000).  I then capture the audio output of the sound module on a separate audio track.  This means I can monitor the audio output of the sound module and re-record the audio so it will always be exactly the same as the initial (same volume, etc.).  When I monitor the audio output of the sound module at my hardware mixer, I hear no distortion of the audio.  The meters of the hardware mixer receiving the audio output of the sound module are well below 0 dbFS - so the audio coming out of the sound module is NOT distorting the AD converter.

OK so here is where it gets weird.  If I slide the midi track forward 20 measures or so (well beyond the location at meas 96, beat 2.5), and re-record the sound module, I get a audio clip that has NO distortion in it: it sounds great.  Yet, if I then slide or copy/paste this audio clip that has no distortion in it to the location at meas 96, beat 2.5, this audio clip will now play back with the distortion, just like the previous clip.

So in sum: the audio output of the sound module itself is not distorted; the audio output of the sound module is not distorting the AD converter, and I can record the audio output of the sound module to CW without distortion as long as I am not recording at meas 96, beat 2.5.  

All the other audio tracks except one play without distortion at meas. 96, beat 2.5.  I am hearing a similar distortion in another audio clip on another audio track at the same meas. 96, beat 2.5.  This other audio clip was also created by first recording a midi track and then using the midi track to drive the sound module. 

Can anyone tell me why I am getting distortion at this one particular location (and not at any other location).  Can anyone suggest a way to avoid or remove the distortion?   Thanks.

 

 

[57Gregy]

Welcome to the forum.
I can't say why this is happening, but you can try moving the clip to another track but at the same time and see what happens.

[JamPro]

Thank you Gregy for your reply.

I have tried creating a new audio track and then either moving the original distorting audio clip to the new track.  When I do this, I get the same distortion at the same meas96, beat 2.5 location.  If I try to re-record the sound module into a new track, I get the same distortion at the same location.

I am very sure that the original clip has no distortion on it.  I have to confirm this by listening to the clip in Sound Forge.  But I feel very confident when I do this, I will not hear distortion on that audio clip.

So my diagnosis is that CW is having some issue at the song location meas 96, beat 2.5 that is creating distortion. 

[JamPro]

Hello.  So I can confirm that if I take the audio clip in which I hear distortion and play it in Sound Forge, it sounds fine: no distortion.

So the audio in the clip is not distorted but I will hear distortion at the specific song location if I play the clip in CW.

I might have found the problem.  One of the other audio tracks that also play at the meas 96, beat 2.5 location has an edit right at the meas 96, beat 2.5 location.  (I created this audio by playing the RD-2000, and recording the output into the corresponding track (track 2 to distinguish it from the track in which I hear distortion) in CW.  No midi was involved.  After recording this, I decided I need to rerecord some sloppy notes in the last measure, so I used the Split Tool to cut the clip and then recorded a second pass on a Take Lane in that track.) If I solo this other track, it plays back fine, no distortion.  But I am suspecting the edit made in track2 is for some reason causing CW to distort when it plays back track 1. 

I will do some further investigation and report back.  It has been my impression for some time now that I am coming across bugs/anomolies in CW.  On a couple of occasions, it seems some of my softsynths are responding to events on other tracks having nothing to do with the softsynth. 

[57Gregy]

Okay. That sounds like you may have split a clip(s) not at Zero Crossings. That will probably make a noise when played back.

[JamPro]

So let us assume you are correct Gregy, and I have made a bad cut not at a zero crossing in (let's call it) Track B.

When I solo Track B and play it back, I hear no distortion.  And if I solo Track A (where there is no bad edit) and play it back, I hear distortion.

Even if you are correct and I have made a bad edit in Track B, there is no way - in the world of functioning audio recording software - that a problem in Track B will cause distortion heard during the playback of Track A when Track A is soloed. 

This kind of behavior should be recognized as a malfunction of the audio recording software.

While I recognize (and appreciate) the CWbBL is free, it has to be said that what I have been describing is clearly a bug in the functionality of CW - and a significant bug as well.  Sadly, I think I have noticed other similar bugs in CWbBL where it appears that things that occur on one track will impact the proper playback on an unrelated track.  These kinds of bugs make the software unappealing to use: BandLab needs to address this problem pronto or risk becoming a joke in the world of audio recording software.

I hope the team at BandLab is paying attention. 

[John Vere]

If it was a bug it would have been reported 20 years ago. 

And to clarify-  do you really mean to say " a glitch" . In  other words there is a short burst of nasty sound at this point on the track. 

I think Greg has it nailed. Those normally show up at edit points. 

Try zooming way in on the wave form at that point. 

[Byron Dickens]

You sure the master output isn't clipping?

[Byron Dickens]

14 minutes ago, John Vere said:

If it was a bug it would have been reported 20 years ago. 

I have been using SONAR,  & now CbB since V6 and have yet to experience symptoms as described unless something is clipping or I cut something not at a zero crossing.

[John Vere]

I just re read the OP and I noticed this- "At that location, the CW meters show the audio to be more than 10 db below 0 dbFS (so the distortion is NOT due to audio clipping)."  

This is a mistake. The meters will not always show things that happen that fast. 

Put Span on the track and see what it's true peak level reads. If this is OK then we have a zero crossing issue.   

[57Gregy]

21 hours ago, JamPro said:

So let us assume you are correct Gregy, and I have made a bad cut not at a zero crossing in (let's call it) Track B.

When I solo Track B and play it back, I hear no distortion.  And if I solo Track A (where there is no bad edit) and play it back, I hear distortion.

Even if you are correct and I have made a bad edit in Track B, there is no way - in the world of functioning audio recording software - that a problem in Track B will cause distortion heard during the playback of Track A when Track A is soloed. 

Good points.
Is there any situation in which the noise doesn't occur? (Didn't read through the whole thread again). It certainly seems like it may be a click or pop from a bad split, but that's probably ruled out now.
Perhaps some superfluous MIDI data sending a note to a synth at that point? 
What happens if you rewind to the beginning and go to Project>Insert Time/Measures and insert a measure or 2? You can undo this by hitting Ctrl Z. Does the noise move to the same amount or remain at 96/2.5?

[JamPro]

Thank you to all who responded.  I appreciate your thoughts

Mr. Vere - "And to clarify-  do you really mean to say " a glitch" . In  other words there is a short burst of nasty sound at this point on the track."

Yes - what I am calling "distortion" is a quick burst of white noise during playback.

"Put Span on the track and see what it's true peak level reads."

I don't think I know what Span is - can you explain?

Mr. Dickens - "You sure the master output isn't clipping?"

Yes.  The levels of the track where I hear distortion are no more that -10dbFS at the point I am hearing distortion.  The level of the master output is no more than -2 dbFS at the point I am hearing distortion.  And I hear this distortion when I am playing back with the distorting track soloed (and no other tracks are soloed).

Like you Mr. Dickens, I am a long-time CW user - I got my first copy back in 1997 or 98 when CW was a midi-only.

Mr. Gregy - "Is there any situation in which the noise doesn't occur?"

Yes - actually many situations.  So I am hearing distortion on 2 tracks (we'll call them track1 and track3) of a project containing 8 tracks in total.  I am hearing distortion (only at location meas96, beat 2.5) anytime I play back either or both of track1 and track3, and any combination of other tracks.  I am hearing distortion anytime I play back with either track1 or track3 soloed.  I DO NOT hear distortion when I mute track1 AND track3.  I DO NOT hear distortion if I solo track2 (track2 is the track that contains an audio clip I edited at location meas 96, beat 2.5 - a possible bad split where the audio was not at a zero-crossing - I haven't actually examined the track to see if there is a non-zero crossing split - but the distortion I am hearing is suggestive of a non-zero crossing split).  I DO NOT hear distortion if I delete track2 or if I delete the audio clips in track2.  I DO NOT hear distortion is I listen to track1 and track3 in another audio editor (Sound Forge).

So while it is possible the edit I made on track2 is causing distortion, I do not hear the distortion when playing back track2 soloed - I only hear distortion on track1 and track3 when those track are unmuted or soloed (regardless of  whether track2 is muted or not).  This is what I think is a CW software problem: something in track2 is causing CW to introduce distortion on the playback of 2 other unrelated tracks.

So last night, I resolved this distortion problem by deleting the existing audio clips in track2, and re-recording the material on that track (same "virtual" instrument, same set of notes).  Having done that, there is now no more distortion at meas. 96, beat 2.5 when playing back any tracks - tracks1 and track3 are now free of distortion.

Fortunately, this problem is fixable.  It took me 3-4 days to investigate and find out what was causing the problem.  Once I had a better idea of what the nature of the problem was, fixing it was the easy part.  So the problem in my project is resolved, but my suspicion that there is a significant unresolved problem in the functioning of CWbBL is as strong as ever.

Thanks again

 

 

[Byron Dickens]

Actually, your fix kinda proves that the problem was in your project, not in the software.

 

And like John mentioned, the meters in CbB don't react fast enough to show things of this nature.

 

Now, don't take this as an insult, but I would have just re recorded the track (like you finally did) days ago and been done with it.

[John Vere]

https://www.voxengo.com/product/span/

Span is free and 1,000's of people use it on the master bus. If you solo a track then you can also use it for troubleshooting or just put it in that tracks effect bin. 

I also use the Youlean meter https://youlean.co/youlean-loudness-meter/

which is free to try but was well worth the $30 ( on sale) as you can drag and drop any audio file and it will analyze it. A must have tool for working with audio that is going to end up on a delivery system be that a CD or the internet.  I can drag and drop finished songs or any tracks even movies. 

[JamPro]

2 hours ago, bdickens said:

Actually, your fix kinda proves that the problem was in your project, not in the software.

Mr. Dickens: I don't understand.  So you are saying that it is proper functioning of CW to cause distortion in the playback of track1 when there is a (presumed) problem in track2 - and track1 is soloed  and track2 is muted?  And you understand there is NO distortion in the playback of track2  when I solo track2 AND there is no distortion in track1 when I play the audio of track1 using a different audio editor?

Please explain - why does CW add distortion to a given track when there is a (presumed) problem in a second track (a problem that cannot be identified when playing back the second track alone)?

Mr. Vera - thank you for the tip.  I will check it out.

[Byron Dickens]

No. I am saying that your problem track is likely hot enough at that one spot that when mixed in with everything else, your master clips. Each track can be fine by itself, but the cumulative levels together can clip.

When you re recorded it, the level was just lower enough to fix the clipping when the tracks are mixed together.

So, it is expected behavior that your master will clip when overloaded.

Edited April 8, 2021 by bdickens

[John Vere]

Cakewalk or any DAW will not create a distorted clip unless there is a reason. I have no clue why your had an issue but as said most of us when we encounter this assume it is something we have created in audio of the DAW and it needs to be eliminated. As @bdickens  said you proved user error, not software,  when you eliminated the track that was causing the clipping.   End of story.  

[JamPro]

Call me stupid: I'm still not understanding.

In CW, I solo track1 and hear distortion when the CW meters peak at < -10bdFS.  I take the same audio clip and play it in Sound Forge, and there is no distortion.

The obvious  conclusion is that CW is adding distortion. 

   

[Byron Dickens]

No. This only happens at one particular spot on one particular track in one particular project. The problem went away when you re recorded the track. The obvious conclusion is that there was a problem with that recording. 

That's just basic logic.

 

If you had provided your project file, one of us could have proved it easily.

Edited April 9, 2021 by bdickens

[JamPro]

 

15 hours ago, bdickens said:

No. I am saying that your problem track is likely hot enough at that one spot that when mixed in with everything else, your master clips.

This cannot be correct because I hear distortion when playing track1 solo - i.e. when track1 plays by itself and nothing else is mixed in.

8 hours ago, bdickens said:

The problem went away when you re recorded the track.

The problem went away when I re-recorded a different track - a track that was not in playback when I am playing back track1 solo and  am hearing distortion.

8 hours ago, bdickens said:

If you had provided your project file, one of us could have proved it easily.

Thank you.  This is a good idea for troubleshooting future problems.  Can I actually post 8 tracks of a 5 min. project here in this forum?  One stereo track of 5 mins. of audio is about 50 mB; not all eight tracks are stereo, but we are still talking about 100s of mB of audio data.  (There is a little notice at the bottom of my forum view that says "Drag files here to attach.  Max total size 4.88 mb.")