Mixing Without Decks

From: Kyle Farrell <kaf@cdac.com>
Date: Thu, 15 Oct 1998 14:27:59 -0700 (PDT)
Subject: digital dj'ing

I wrote up a brief how-to guide on dj'ing used Acid & posted it to
alt.music.makers.dj in hopes of sparking a thread.  No luck.  Anyway,
the article I posted could be used as a starting point. 


Hey gang-

Anyone using computers to mix?  I picked up a copy of Sonic Foundry's
Acid & have put together two CDs of material so far. I've been pretty
surprised at what I've been able to accomplish.

I've done some dj'ing years ago with a pair of 1200s, and this is
nothing like that.  It's not real time one bit, plus their is very
little hands on feel.  Don't think about selling the 1200s for a
computer, but if you could steal some cycles from a friends computer
give it a shot.

I'd like to talk with anyone who is/has tried this type of thing on
their computer and their experiences.  I'd like to know if some of the
more turntable-style effects are possible.  For example, how might you
scratch into a song?  I guess you could sample some scratches, but
that's fairly bogus.  Anyway, I'll outline the basic methods I've been

* Get the audio onto the hard drive.  Either extract digital audio
from CD (preferrably) or record from the line level in on the
soundcard.  I use records & (rarely) tapes as source material.  You're
going to need at least 1.5 GB for a 70 minute mix (space for the
original songs + 1 large 700 MB wave file for the mix + breathing

* Using Acid, pencil in the first track.  Count the bpms for the song
& set it correctly in Acid.

* Pencil in the next song, again be sure you've got a rough estimate
on the bpms.  Choose a part of the song where it'll be easy to match
the beats.  Zoom in *very* close to a couple of the beats, visually
adjust so that they match exactly.  If you can see that the beats don't
match, you'll definetely hear it.  Do this in multiple parts of the
mix, adjusting either the position of the 2nd song or the bpm
(probably both).  The goal here is to get the bpms matched up

* Now slide the 2nd song to where you really want to mix it in.  Intro
not long enough?  Simple, just pencil in the intro once, then lay it
down again.  You've now done you're own extended intro dance remix :)

* The time & tempo are now locked so I next work on the volume.  Acid
has no crossfader, but you've got something more flexible: volume
envelopes.  Pay careful attention to these & add points to the
envelope you want the volume to change.  One critical thing here:
we're mixing in the digital realm.  Keep an eye on the levels.  If it
goes above 0.0, lower the volume of one of the tracks.

* Continue adding songs until you're bored silly.

* Mix the final result down to a single wav file.  At this point I
usually dick with the mixed wav file in SoundForge or Cooledit to
spice things up a bit.  Some fun things to do are:
	* Reverse the last measure of a phrase
	* Add effects, panning, filters, flanging, etc. (actually,
	  this can be done in Acid too with DirectX plugins)

* Dump the final mix to CD-R.  Jump in the car, plop in the cd and
listen away. :)

Anyway, I've had a good time doing this.  Even though it's vanilla
beat matching & adding effects, it's fun.  One thing about Acid is
that it'll stretch the song without changing the pitch.  This is good
on some songs but results in annoying phasing on some white-noise
snares or hihats.  YMMV.

If anyone has similar experiences using Acid or other software, I'd
like to hear about it.  I've been using a brand spankin new PII-450
with a fast disk which helps out on a lot on the audio processing end,
but this stuff should be possible with slightly older technology.