[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Date Index][Thread Index][Author Index]

Re: Another new member

Someone asked about looping with a sampler. Here's a repost of my tips for
setting up a feedback loop on the S2000/S3000 series with the EB16 internal
FX board.

From: "Fish" <fish@ndirect.co.uk>
Subject: [Akai] Re: Remix tip for Akai users

To continue with this excellant thread of creative tips, I thought I'd
share with you my experiments with feedback loops using the EB16 effects
expansion board for the Akai S2000 and it's bigger brothers. 

I originally discovered this technique while playing about with a friend's
Roland tape delay and a wah-wah pedal but it's quite easy to reproduce with
the EB16. The basic theory is to take a sound, put it through a slowly
sweeping band pass filter, delay the signal, and then feed it back to the
start where it gets filtered, delayed and fed back again. 

Now, you're probably thinking this is a bad idea and will result in the
nasty howl around feedback which we're all familiar with having plugged an
output into it's own input after one spliff too many in the studio. But
it's the sweeping band pass filter that's the key here. As the filter only
lets through a certain range of frequencies and eliminates the others, by
the time the delayed signal is fed back to the input the filter will have
shifted frequency sufficiently to prevent the signal building up into that
nasty howl. 

Depending on the original sound and by adjusting various parameters you can
achieve a number of weird and wonderful effects. Play a big chord using
nice thick pad and pass it through the feedback loop and you get a
beautiful evolving swirl of sound as the various harmonics are picked out
and emphasized. Take a techno stab, played in time with the delay and your
riff takes on a life of it's own. Or a few Rhodes chords add a really
spacey dimension to a dub track. White noise textures also work well with
the feedback loop adding a lot of movement to the sound. And of course with
an electric guitar, which is what I first made the effect for, your average
solo will take right off into space! 

But I'm sure you'd rather create the effect yourself than listen to me try
and describe it. 

A word of warning is appropriate here. Because you're feeding the Akai's
ouput back to it's input, there's a risk that the signal levels could get
enormously high. The best sound is right on the limit before it tips over
into a howling shriek, so you need to be very precise with the parameters.
But, like many great sounds, this comes from experimental use/abuse of the
equipment (the Roland Bassline and the wickedly detailed breaks of
drum'n'bass spring to mind). The Akai is a sturdy bit of kit and can
probably take it in short doses, but you're ears aren't--so please, BE
CAREFUL! Obviously I can't accept any liability for to damage of your
equipment or hearing! :) 

Got that? Ok, here's how you set it up: 

I can only describe how to do this on the S2000, but I expect if you own
the S3000xl you'll be able to work out how to acheive the same effect.
Also, if you have multiple outputs you can be more flexible with what you
plug into what. 

1.Sample or load an initial program. Good sounds to work with are thick
pads or textures with a lot of harmonic content covering a wide range of
the frequency spectrum or buzzy analogue leads with an open filter. 2.Go
into single>edit and find the page OUT L/R and check that the level
parameter is up at maximum and the pan at centre. 3.Page down one step to
the Out Fxbus page and set the FXbus to FX1 with a send level around 75.
4.Make sure that no FX override is set for any of the keygroups or they'll
loose the effect. 5.Provided you're happy with the source sound, now choose
the Effects button. Pick any free Fx slot to use and hit the Edit button to
get into the parameters for FX1. 6.Page down until you get to the
Ringmod/Distort page and set it to Bypass. 7.Page down again and set the
Equalise to Active. 8.To cut out the outer frequencies you need to
eliminate the high & low eqs . Page down to the EQ Low page. Set the
frequency to around 100hz and spin the dB right down to -oo to cut out the
bass frequencies. Do the same with the EQ High page (a couple pages down)
and set the frequency to about 10kHz and the dB all the way down. 9.It's
the band pass filters which you're interested in. Set the frequency to
around 800hz, the boost to about +8dB and the width around 10 (you can come
back and change this later to suit the sound and how pronounced you want
the sweep effect to be). Set the second band pass up in a similar way to
the first. 10.Page down a couple of times and you'll find the BPMOD pages.
Set the sweep rate to sloooow; it's best at around 0.1 or 0.2Hz. Try a
depth of around 30. If you're using the second band pass filter, set it up
in a similar way with the same rate. 11.You can either bypass the Mod
section or add a little chorus to the effect. 12.Set the echo mode to Mono
L+R and set the delay time to somewhere between 200-500ms or set it in time
with the tempo of your track with each delay equal to an 8th note.
13.Ignore the Damp parameter and set the Fbk to 0 (remember we're going to
physically feed back the Akai's output to an input - but NOT YET!!). 14.On
the next page, leave the offset to 00 and set the Output to ***POSTdel***.
This parameter is particularly important for the effect to be anything
other than nasty howl around. 15.You can ignore the reverb parameters for
the time being as we'll bypass this later. 16.On the Dist/EQ page, turn the
Level right down to ***00***. This is another potentially speaker saving
parameter which should not be ignored. 17.On the MOD/ECHO page, turn the
Level right up to 99 and leave it MID panned. 18.Then on the REV, turn the
level all the way down to ***00***. 19.Leave the Path control at the
default 00 and Program Signal to Stereo should be set to ON. 20.Finally hit
the Effects button and page all the way down to Left ADC input and set it
To:FX1 with Thru: set to ***00***. 

Okay, provided you've followed these instructions carefully, it's time to
give it a try! 

Turn the REC GAIN level to 12 o'clock and the main volume ALL THE WAY 

Now take a patch cable and connect either the L or R of the Akai's stereo
output and plug the other end into the L/MONO input on the front panel. 

Now SLOWLY turn up the main volume. If you immediately hear a howl before
playing any notes, go back and check all the parameters above- particularly
the ones highlighted with astrixes. 

If all is going well, play a few notes and you should hear the effect of
the sound being delayed and fed back through the EQ filters. Slowly
increase the volume, if it grows into a howl, just turn down the volume so
it doesn't feedback on the next delay. It will take some practise to get
the levels just right, but you should be able to find a level where the
sound sustains without rising into a howl around but doesn't decay too

Then go back and fine tune EQ section. The parameters to play with are the
depth of the Modulation and the frequency, boost and width of the filters.
More meaty sweeping effects can be achieved by increasing the width of the
bank pass filters, while decreasing the width will give a smaller chirpy
sound. Just remember to keep a hand on the Main Volume control in case the
levels get to high. Or if you're studio is equipped with a limiter, patch
it into the loop. 

Truely psychedelic effects can be created by gating the source sound by
applying an LFO to the amplitude, running in time with the delay, which
will creates cascades of frequencies. 

Finally, add kick drum and record to DAT. Wait for your record to go
platinum, and send me a cheque for the inspiration :-) 

Best of luck! 

PS. A useful addition to the chain is to have control over the amount of
signal being fed back to the input. I use an analogue volume pedal between
the Akai output and it's input, but it would certainly be nice to have MIDI
control over this. If anyone finds a way please let me know! 
fish@ndirect.co.uk   http://www.ndirect.co.uk/~fish