[RWP] Time Selection and Trimming Midi Loops

[indigo]

Hi Colin,
All commercial loops are trimmed to exact zero crossing point;  not to 
128th note increments, or milliseconds, which our ears would pick up 
these days, but to single sample accuracy.
Our brains are so trained to hundred percent timing now in pop music, I 
know that I can't help immediately hearing a few samples off in timing.
The same thing has happened to us since electronic guitar tuners came along.
We all expect to hear perfectly tuned guitars now.
Go back and listen to early Rolling Stones and Beatles and hear how 
mistuned their guitars were, and most of us didn't even mind it in those 
days.

I haven't tried creating perfect audio loops in Reaper yet, and probably 
won't, since Sound Forge is specialized for it; and it's so easy in 
Sound Forge.
I use a fast new computer for seriously working at music, but I often 
practice on this slower old one that I risk getting viruses online and 
use for email; and you're right on that latency is keeping me from 
getting the metronome exactly onto the beat.
The term snap to grid is in all descriptions of new Reaper versions  and 
has to be referring to audio quantization, not to snap to zero crossing 
point for looping, or snap to grid when quantizing midi,  which is 
nothing to brag about, all midi sequencers snapped to grid in the nineties.
Audio quantization isn't exactly leading edge technology either, 
invented way back before2000 by Propeller Heads in Recycle, then 
developed to a fine degree in Acid Pro, and everybody has it now.
There are different names for it, like Audio Quantization in Sonar and 
Beat Detective in CueBase.
In Propeller Heads Recycle you can take a short phrase of audio in 4/4 
and change it to 3/4 and hear it as a waltz, or 5/4, 6/8 or anything 
else you want, and it's perfectly natural sounding.
Recycle chops up the audio into little chunks, each with a loud 
transcient, like the kick drum, then aligns those transcient chunks to 
whatever grid you choose, then does instant cross fades between the 
chunks, so the result is seamless.
Same feature in Doctor Rex.
In Sony Acid Pro, you can import a whole audio song, as long as it is 
played mostly in a steady time without huge shifts in timing, tell Acid 
to align its beats to grid, and in a few seconds you have the song 
exactly aligned to measures and beats.
I don't know if you could export the song from Acid Pro along with its 
measures and beats grid, to use in Reaper; Acid Pro does it so well that 
would be a good excuse to keep Acid Pro on one's computer.

I can tell from reading the Cockos forums that audio quantization is in 
Reaper, but just can't locate it yet.
I think there's no choice but to sift through the standard Reaper manual 
and the actions list until I find it.
Standard Reaper may expect you to do it by mouse, and doesn't have an 
assigned keyboard shortcut for snap to grid; since I read one Cockos 
forum post complaining about losing his KB shortcut for snap to grid.
Knowing how much Reaper treats audio and midi alike, I expect you just 
set your midi quantize grid to eithths, sixteenths, 32nds, and audio 
snap to grid action will move the kick drum transcients to the nearest 
grid line.
If you're way off the beat it could snap  to the wrong grid line, so the 
need to get as close as possible with tap tempo first.
Okay, when I find the action, I'll assign it an available shortcut and 
post it here.
Thanks,
Indigo L


On 4/16/2012 7:48 PM, colin McDonald wrote:
> as long as you have no latency in your system, you can align, or sink
> the audio track to the metronome...
> any amount of latency will throw this off as I discovered and posted
> about some time ago.
> Yes, the tap tempo function works in ReaAccess, but again, latency,
> processor speed and all that will play into the over all accuracy and
> timelyness of the tap tempo function.
> with recorded audio, it's more difficult to utilize measures, beats per
> minute, and all that kind of thing, along with the metronome...there
> aren't too many drummers or musicians who can keep absolutely perfect
> time, unless the drums etc have been recorded using a click track.
> you should be able to utilize the functions you indicated using midi and
> software bassed instrumentation where you can use electronic/coding
> manipulation, as aposed to time bass manipulation.
> hope that makes sence...you should be able to get zero crossing loops in
> reaper without any trouble. I haven't used it, but there is snap to and
> zero crossing functionality in reaper that is easily accessed with
> ReaAccess keyboard commands.
> with jims scripts, it makes it easier to go to the beginning and ends of
> items or selections to nudge or trim them to obtain that zero crossing.
> I don't know precisely what the zoom factor is if you will, but I think
> you can get it out to 128 parts per beat....a bad way to explain it, but
> essentially you can have 128 incraments in a single beat as recognized
> by reaper weather it's midi or audio...all accessed using arrow keys and
> scrubbing/nudging commands.
> perhaps 128 incraments isn't enough for you to create a zero crossing
> for a loop, but I would suspect that a milli second or two wouldn't be
> noticed by the human ear on a drum loop.
> especially an audio drum loop.
>
> Regards
> Colin
> ----- Original Message ----- From: "indigo" <33indigo at charter.net>
> To: "Reapers Without Peepers" <rwp at reaaccess.com>
> Sent: Monday, April 16, 2012 3:03 PM
> Subject: Re: [RWP] Time Selection and Trimming Midi Loops
>
>
>> Colin, I haven't done it yet, but it seems to me if you can nudge or
>> scrub to the very first note of your audio, and set beginning of loop
>> with alt+left bracket, then move to the very last sound on your audio
>> item, and set the end of loop with alt+right bracket; and when you
>> play the loop you hear nthat notes aren't being chopped off at either
>> end; then you're in a good position to split items with shift+S and
>> end up with 3 items, item 1before your music begins;item 2 your music,
>> and item 3after the end of your selection.
>> You delete item 1 and item 3, and you have the audio loop.
>> Colin, you know, at this point; if I really wanted the audio to loop
>> seamlessly, I'd take it to Sound Forge, where I have experience with
>> adding or subtracting samples to a loop, until I get a perfect zero
>> crossing, no click or gap.
>> But, please tell me if this is right; first, to get the audio aligned
>> with beats, in Reaper; there's a setting in general project settings
>> to choose measures beats length.
>> I'd select that.
>> Then, right near that selection there's another that seems to be for
>> forcing to align with beats, not the exact words, but I believe that
>> is what it's for.
>> That selection was also close to one about Reaper's default stretch
>> plug, Elastique.
>> Then I'd turn on the metronome and learn if the audio's loud
>> transcient points, like the kick drum, are being forced to align with
>> beats.
>> Actually, it might be better first to manually align as close as
>> possible with the tap tempo button, if that works in ReaAccess, then
>> force the transcients to align with beats afterward.
>> When I get back in Reaper, I'll get the correct wording for those
>> project selections and test this out; but am I right about what they do?
>> Then, after the audio aligns with beats, I'd save it and take it to
>> Sound Forge to make it loop seamlessly.
>> I'm loving this thing!
>> Indigo L
>>
>> On 4/16/2012 4:18 PM, colin McDonald wrote:
>>> precisely.
>>> you can do this with regular recorded audio as well.
>>> Not as straight forward as selecting beats because normal audio isn't
>>> clocked obviously, but you can set a tempo or BPM for the project which
>>> is fairly accurate.
>>> If you know that your material is at 120BPM, you can set the project
>>> tempo and then edit acordingly.
>>> Using track Items is truly an excellent way of editing audio.
>>> you can have unlimited items on each track which can be easily selected
>>> using the control and arrow keys.
>>> it gets even better when you get into scrubbing and various nudge
>>> functions.
>>> Regards
>>> Colin
>>> ----- Original Message ----- From: "indigo" <33indigo at charter.net>
>>> To: "Reapers Without Peepers" <rwp at reaaccess.com>
>>> Sent: Monday, April 16, 2012 2:07 PM
>>> Subject: [RWP] Time Selection and Trimming Midi Loops
>>>
>>>
>>>> Maybe this is obvious to you, but I just now got it.
>>>> I have a midi loop that is 2 beats too long, so it loops with a silent
>>>> gat at the end.
>>>> I pressed the home key; and hear 1 measure, 1 beat.
>>>> I pressed the end key; and hear 9 measure 2 beat, which is the end of
>>>> the item.
>>>> I can estimate the silent gap was those 2 extra beats.
>>>> I pressed home and set beginning of loop with alt+left bracket.
>>>> I pressed end and again hear 9 measure 2 beats.
>>>> I hold shift and press page up twice to back up 2 beats; so I'm now at
>>>> 9 measures.
>>>> I press alt+right bracket to set end of loop.
>>>> When I play the loop with looping set with ctrl+R; it loops perfectly,
>>>> so the extra 2 measures are excluded from the time selection, but they
>>>> are still included in the item, just not selected.
>>>> How to trim off the extra 2 beats after the 9 measure loop:
>>>> I press shift+S to split the item into 2 items.
>>>> Now I have 2 items, the first item with my 9 measure loop, the second
>>>> item with the silent 2 measures.
>>>> While on the selected track, I press ctrl+right arrow once and hear
>>>> the first item announced.
>>>> I press ctrl+right arrow again and hear the second item announced.
>>>> I press delete and the second item is deleted.
>>>> I save the project with the now perfect 9 measure loop.
>>>>
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