Trimming a mastered WAV without losing quality
I ran into a peculiar problem. I created a track for mastering with a bit of silence before the track. The track sounded great after mastering. I wanted to trim the silent bit out in Ableton, however, when I drop the WAV in, the sound quality significantly decreases.
Any ideas what’s going on?
What’s a safe way to trim the WAV without messing up the quality?
Don’t use Ableton, use an actual audio editor rather than a DAW… like, Soundforge, Audacity, something like that. For the record - I cannot attest to Audacity for this, as it is an audio editor with some DAW-like features, and I haven’t measured it… but SF is solid for this sorta thing.
So long as your editor works on the audio in its original sample format (bitrate, frequency, etc.), then WAV is a lossless format and you should be fine. However, if you load it into Ableton and most other DAWs, then it internally works at 32 bit, possibly higher frequency, yadda yadda yadda.
Shifting your sample format like this can introduce artifacts, and Ableton is notoriously horrible at coloring your audio as well (for example, consolidate actually changes the sound… was chatting with Warp9 about it, and ran an actual test to verify it, and yeah… consolidate is freakin’ BAD in Ableton, you should never use it). Your experience with other DAWs may vary, but for the most part, they are not the best choice for minor edits like cropping.
Ableton is fine for this, just turn off warping for the song when you drag it into the app. When you’re done, make sure you have dither turned off in the render dialogue too. It’s no different from any other wave editing app at that point, at least in terms of sound quality.
Tarekith - Actually, the internal sample format shift will still introduce some artifacts to the process that you might want to avoid after you’ve mastered it. This is measurable. If you want the exact same untrimmed bytes out that you put in, you can’t use Ableton.
What sample format shift? I’ve never even heard that term before, can you clarify a little so I can understand?
Yeah I would use Audacity for something like this.
By sample format shift, what I mean is that internally, Ableton works in 32 bit whereas the master is probably 16 bit, and maybe a higher sample frequency than your master’s (though that is probably less likely).
Once you’ve got your final master, if you load it into Ableton, it will shift back into 32 bit, then when you export, it’s back to 16 bit, you will not have the exact same bytes that you fed into it (and I’m of coz not counting the ones you trimmed). Even with warping off, you’re still probably going to add a little bit of color to your sound.
Whether or not it’s audible to most people is a different question entirely, but I personally would think it’s worth tryin’ to keep your master as clean as possible.
That said, my understanding is that a master should have a little bit of leading silence… though I don’t know how much you are wanting to trim, Uni. Redbook, which isn’t exactly important any more, actually wants a 2s gap… but that could mostly go at the end. A short bit of lead in for your transient, of coz, but that doesn’t really need to be very much. I usually make the lead-in about .5s myself, though that isn’t anything I’ve specifically measured or any such thing, just what seems OK to me.
I’m sorry, but that’s just not true. I just tested this in Live 9.5. Took a 16bit song, duplicated it to a new track and cut off a minute at the end. Exported the edited song at 16bit with no dither, and it phase cancels 100% with the original 16bit version I started with.
I’m not saying Live is the best tool for things like this, but it can be used too if that’s all the OP has. You can find more info on what operations in Live are nuetral or not in the audio fact sheet they have posted on the site:
I retract, thanks, Tarekith.
Note to Uni - Tarekith mentioned that you must disable the dithering in the export if you want it to be seamless (as well as his original statement to turn off warping, of coz). Don’t forget to do that.
No worries man. A lot of people have this notion that Live is messing with their audio more than it really is, I just want to see them get more credit for being sound-focused too 
Uni, also worth noting, from the page Tarekith linked:
[QUOTE]Rendering is a neutral operation under certain conditions:
While I did say that it was unlikely that it wasn’t, this is still a concern to make sure you check for - according to the fact sheet there, your sample frequency must be set the same in Ableton as your original file if you’re going to have uncolored export. Double check that before you do this.
Hrm… upon further testing here, my actual assertion is correct… the bytes you get on your output are not exactly the same bytes that are in your input… they are very close, so close that it will sound to most, if not all, humans that it cancels out with phase cancellation, but not exactly the same - not a 100% cancellation in mathematical terms. Probably not audible to most humans, but it is not a perfect trimming of your master. If you load your WAVs into a hex editor, you will see that the numbers are different in a before and after Live export. (For my testing, I used a downloaded 500Hz test tone.)
Sound Forge, however, when it trims, is trimming the bytes from the data itself, and your exported bytes will be exactly the same as those you input, minus whatever was trimmed. I tested this by trimming exactly one sample off of the front of my test tone, and the bytes moved forward in the file by exactly 2 positions in my hex editor (i.e. one 16 bit value), but otherwise remained exactly the same.
It is an academic discussion if most people can’t hear it, but what I said was still true… your export from Ableton will not be identical to your input. Just very, very close, probably close enough to be fine.
Worth noting - I tested Live 9.2.3, Audacity 2.1.1 and Sound Forge Pro 11… Audacity also modified the output. Of what I tested, only Sound Forge gave a perfect export, though I am sure there are other audio editors out there that will do it - as I said earlier in the thread, Audacity tries to straddle the line between sample editor and multitrack audio… (hrm, would it still be a DAW? These days, DAW means so much more, so not sure what to call it). Whatever we call it… Audacity is not a significantly better option for this operation than Live.
(This is a brilliantly interesting conversation, BTW, thank you Tarekith!)
What a pair of geeks… 
! 
Thank you, Patch! Proud of it!
The mastering engineer should of really done that for you.
But use something like pro tools to trim it. Zoom into the zero point at the beginning and end where the audio starts and ends and trim.