beat matching question

[trev]

I want to make a compilation cd, and does anybody know the best way to beat match songs so they blend together while overlapping? I've used the envelope tool quite a bit, but thats only for short quick changeovers. I'm looking for longer mixing times.

Any ideas?

[alatham]

You would need to figure out the exact BPM of each track and then use Change Speed on one of them.

The hard part is finding out the BPM, unless it's listed somewhere. Audacity supposedly has a Beat Finder, but I haven't had any luck with it (not surprising, given how hard beat matching is for a computer, remember that we're much smarter than computers).

Once you know the BPM of each track, you need to either use Change Speed or Change Tempo (Change Tempo will keep the song in the same key, Change Speed will not). The equation you need for the percent change is:

Percent Change (applied to song 2) = 100 - (100 * (BPM1 / BPM2))

If we have song 1 = 95 BPM, and song 2 = 100 BPM. This equation gives an answer of -5 percent to be applied to song 2.

Can someone check this to make sure it's right? I think it is.

There is no short way for Audacity to do this until the Beat Finder works properly, but I wouldn't hold my breath.

[trev]

I couldn't figure out how the beat finder works? I was thinking it was my computer that wasn't working properly. Do you know if there is a way to gradually change the tempo over a certain period length, not just abruptly when using the "change tempo" control? I haven't been able to figure that one. Other than setting several tempo changes, but that's really hard to back track when editing.

And on the subject, when beat finder does work, I hope you can select the length of time that you want covered, cause the songs are not always the same beat throughout.

Trev

[trev]

Scratch that last sentence, I just wasn't zoomed in enough to see what the beat finder was actually showing me. I was expecting to see a number such as 120 bpm, but it only shows where the beat peaks are in a linear graph.

As usual I must re-arrange my concept of how I think it should be done.

Trev

[alatham]

Do you know if there is a way to gradually change the tempo over a certain period length, not just abruptly when using the "change tempo" control?

That would be called Accelerando or Ritardando in musical terms. Unfortunately there is no way to do that in Audacity at the moment.

[mrvanes]

I would love to see this implemented as well... It would make audacity a nice 'mix compilation' tool!
Is there an alerative editor/script/tool that could gradually increase/decrease a songs tempo over time, outside Audacity?

[mox]

It seems that mixmeister do that (http://www.mixmeister.com) but is not free.

[steve]

Is there an alerative editor/script/tool that could gradually increase/decrease a songs tempo over time

There is a plug-in for Audacity called something like "Turntable Warp". It is available from the main Audacity web site.

[m0ru]

As for open source applications, one could also do bpm-synching and changing with Mixxx (at least manually/live, though I guess there should also be a way to automatize this for better control over the graduation)

[Dunkelseele]

Hi, I just registered to tell you, there is a free tool downloadable at the Mixxmeister-website, which determines automagically the BPM of any given mp3 or sound-file. I don't know however, if the calculated BPM is of any worth. I myself don't know too much about sound editing and stuff, but the easy formula above and the tool aforementioned did help me to even out some pieces and samples for a project - so thanks!

Best regards