Hello,
 
Im trying to "humanize" a track that has all midi instruments by inserting temp changes and adding series of tempos at different spots, like before chorus, during bridge, etc. When the song reaches any of the temp changes, it almost sounds like an audio dropout everytime a new tempo comes up. Almost a pop, click kind of sound. If I export the song to .wav, I can play the .wav and it sounds fine. But when playing the actual project, I get the pops/ dropouts on the temp changes. Any idea what could be causing this? Not low on memory, cpu usage well below 50%, Thanks
 
 

Are you using any effects that are synced to tempo?  If it is a delay effect, try setting the delay time manually to a suitable average value.

Pump up your I/O buffers, ASIO latency, prepare using X Millisecond buffers in  Preferences -MIDI playback and recording section, update your interface drivers and firmware, install X1D, run windows update, run chkdsk and defrag.

Cheers...

It is likely because of the online rendering feature which is lower quality so you can audition time stretching  changes while you work. You said it sounds fine after export. That is because when you export it is using the offline algorithms which are higher quality and removes the artifacts that the online render algos produce. If you are happy with your timing changes but need to keep working on the project then bounce all the audio tracks. In the Clip Inspector there are various offline algorithms to choose from for different types of material but I find the Radius ones work well for most audio.

Kev999's answer is probably the best place to start. Tempo-synced effects typically have difficulty with tempo changes, often resulting in clicks. The Sonitus Delay is particularly bad about it, but the effect can be heard even in more modern plugins such as ValhallaDSP's UberMod.
 
The solution is to turn off tempo-sync, either across the board or temporarily during the tempo change. Most delay plugins allow you to automate tempo sync, so you can turn it off just before the change and turn it back on after.

I've had this and it did not improve after exporting.
 

Kev999
Are you using any effects that are synced to tempo?  If it is a delay effect, try setting the delay time manually to a suitable average value.

This was suggested to me at time and to be perfectly honest, I haven't even checked it out yet, but it is only certain patches on certain synths.
 
Scrub that!
 
I've just checked a known rogue patch, it's Dimension Pro > Pads > Defeated
 
There is a Phased Delay on Element 2 in the Fx section.
Switching this off removes the tempo change glitches. This is great news!!
I'm now going to add my own phased delay and experiment.
 
Thanks for sticking with this one everybody!