Q: Explosion when using Smart Strings

I should add that the song was started on the iPad Air, then transferred over via iCloud to the new iPad Pro. I've tried duplicating the problem creating an entirely new song on the Pro. So far, no problem. And the sonic "boom" only occurs with strings. (Last time I tried, it shut down the sound in GB entirely. Had to go out to Safari and play a youtube video to restore lost sound.) No problem with keyboards. Well, I feel like I'm talking to the wind here, anyway. Best I can figure so far is that there is something about the GB file, coming over from the Air, that GB strings on the Pro doesn't like.

Following up, I finally tripped the same problem with keyboards as well. This time the "boom" embedded itself into a different drum track. Repeated plays knocked out the sound. Exited GarageBand, out to youtube to restore sound. Except when returning to GB, the boom was gone. So I lowered the attenuation on all the drum tracks (they were peaking quite a bit – I hadn't adjusted any track levels yet), and tried a scratch cello track again. This time, no sonic explosion. So now I'm thinking all this may actually have had something to do with too much peak distortion at once. I will keep posting my findings until I have successfully tracked an entire string section. This may be helpful to somebody else in the future.

I've now isolated the exact moment in the song where the sonic "boom" occurs, and it is in the same place in both tracks. The "explosion" happens when there are two bass drum hits in rapid succession (like 16ths). The kit sound I am using is SoCal, set for full velocity. I edited each track, just completely cutting out the section of each track where the second 16th note on the bass drum occurs, and the problem seems to be gone now. But I will keep working this and posting until the song is finished. It does appear that it was working with the string and keyboard sounds that triggered the boom. I don't understand why or how. But I hope this is behind me now. It is a most frightening sound, capable of blowing speakers and ear drums. Believe me when I say if you heard this sound in any other context or setting, you would be very afraid. It really does sound like the end of the world, or at least your city.