Holiday shop via this link to support the forum!
Weird issue with Reaper and "gluing" audio
Old 14th December 2011
Lives for gear
shponglefan's Avatar

Thread Starter
Weird issue with Reaper and "gluing" audio

I probably should post this over at the Cockos forums, but thought I'd post here as well in case anyone can offer some insight.

I've used Reaper for recording audio in the past, but usually I just have an entire MIDI sequence for the entire track, so I record any synth audio start-to-finish.

This time I wanted to record a drone sound and just loop it. So I recorded a short 8-bar loop. But there was a tail at the end of the loop, say an extra bar. So I simply truncated the loop down to 8 bars, then hit "glue items" to get rid of the tail. For some reason, this introduced an audio pop at the end of the loop.

But, if I copy and pasted the loop, truncated the first one down to 8 bars and then glued the first and second loop together (so 16 bars total), I would not get a pop. Then I can reduce the 16 bar loop down to 8 bars, "glue" that one and still no pop.

So at least I can make a loop using the "glue items" feature with no pop, just with a few extra steps. But I'm wondering why truncating the initial loop and "gluing" it by itself would introduce this pop at the end. I should also note I tried this several times with a couple recordings, so it's not just this one recording.

Misc details: Reaper v4.13 (latest), audio card is M-Audio Profire 610 w/ latest drivers, 32-bit Windows XP w/ 4 gigs (3.2 usable) of RAM. Audio recorded @ 48 kHz, 24-bit.
Old 14th December 2011
Lives for gear
shponglefan's Avatar

Thread Starter
I should also add that I did not do any cross-fading when I copy-pasted the second loop and glued them together.
Old 14th December 2011
Anytime there's an abrupt start or stop to audio signal that forces an 'instant' transition from -inf dB (silence) to audio signal, or vice versa, you'll get a 'pop' of the magnitude of the audio signal. It's the 'ultimate' transient, in a sense, a vertical line.

You can eliminate the pop by fading up from -inf dB to the full signal (or fading down in the case of cutting to silence) or, in other situations, by crossfading that signal with another.

In the case of your edited loop, I'd assume that your butt splice (loop end to loop beginning) had a small enough abrupt transition that whatever pop there was was not heard.
Loading mentioned products ...
Post Reply

Welcome to Gearslutz Pro Audio Forum!

Registration benefits include:
  • Ability to make and reply to posts
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get instant lifetime access to the world's best private pro audio Classifieds for only USD $20
  • List your eBay auctions for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.

Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread Starter / Forum
KevChelios / Newbie audio engineering & production question zone
PinnacleProdUK / Music Computers
ampexfanatic / Cockos Reaper
shelsmusic / Music Computers

Forum Jump
Register FAQ Search Today's Posts Mark Forums Read Search