Removing Unwanted Distortion - Boss

GT-X Setup Manual

be disappointed; indeed, I was about to throw out my GT-3
because I though it was too noisy—but having eliminated
noise from my system (which cost very little!), I realised the
GT-3 was great! Anyway...enjoy!

Removing Unwanted Distortion

Remember we took a good look at the meters? Well, the
GT-3/5 level meters are your friend here as well. In section
7, I said make sure NO SIGNAL EVER PEAKS ABOVE
95%. Well I meant it. What happens if you go too far is the
signal exceeds the GT-3/5's limit and clips. As I have
already mentioned, this clipping will be heard as distortion,
which may be just little clicks or a crackle.
Removing this distortion is fairly easy. First, re-read section
8 where we set up the master level appropriately, and found
out what the target effects chain level is.
The GT-3/5 manual suggests using the meters to identify
clipping by any device and turn its output down. However,
clipping may not manifest itself against the device that is at
the root of the problem. It is most likely that the Master
Output clips, but the other effects don't. You may be
tempted to reduce the master level, but that is not the
appropriate way to do it. What is happening is that you are
putting a boost on one of the effects in the middle of the
effects chain. This will not show up as a clipping in the
middle of the chain. If you use the 'Clean' patch to find out
what your target master level, and target effects chain levels
should be, you can then identify which effect is boosting the
volume above the expected effects chain level and turn it
down.
As I said—although most clipping appears to be at the
output, turning down the master level just isn't the
appropriate way of going about fixing it. What will happen
is that one patch will be loud, another of your patches will
be quiet, and you really haven't gained anything. Indeed you
are effectively introducing another problem—that is one of
uneven output levels between patches. This is exactly what
we fixed in section 8.
We will now take a look at how we can identify clipping at
any point in your system and eliminating it—I will also be
going right through into Cakewalk or Sound Forge on the
PC as well to show you how you can identify clipping in the
sounds you are recording.
There are four places that you are going to be able to detect
clipping, elsewhere than on the GT-3/5. These are:
1. The main output—either Speakers (or)
headphones.
2. The mixing desk meters, monitors or main outputs.
3. On the PC once you have the .wav file.
We will look at each of these in turn.
© Copyright 2000-2002 Barry S. Pearce et al.
Section 9
Again, there is a huge variety in equipment and possible
configurations out there so I will talk about my equipment
so that you can relate my experience to your own particular
situation.
The filtered output from my Palmer PGA-05 goes via 2
XLR balanced patches into 2 channels of my Peavey
RQ200 six channel mini console. I have one set of main
outputs from the console going to another Alesis RA100
studio reference amp and then into a pair of Alesis Point
Seven Shielded Reference Monitor speakers. The other
main outputs go to my PC audio in. I have a Creative labs
SB Live, under Windows 98. I then use Cakewalk for
recording/sequencing and production and Sound Forge for
.wav file editing and CD Architect for audio CD production.
I also have a set of headphones coming from the RQ200 to
provide monitoring. In addition to the above I use an Alesis
SR16 drum machine, which is connected via 2 unbalanced
cables into one of the RQ200's stereo channels. Just for
curiosities sake, for vocals, I use a Samson S12 mic, which
goes direct to the mixing desk.
As we have said before, hard clipping generally manifests
itself as clicks, crackles, or general distortion and soft-
clipping as more of a light->heavy overdrive type sound, or
in one case of a clip on a low frequency on my system it
sounded very similar to speaker rumble or rattle! The point
is that it is fairly obvious once you know what you are
listening for—and if you don't know what to listen for you
will certainly be unhappy about your sound already. Maybe
it sounds a little crunchy when you wanted clean.
To identify the cause you need to run through your system
bit by bit. Clipping will usually be caused by one unit's
output being too high and overdriving the input of the next
in line. However, be aware that with units like the GT-3/5 it
can be completely internal, and also you may have more
than one unit clipping so cutting back may not solve the
problem completely first time.
I would like to point out that if a battery is running out of
power, and that battery is used in one of your units, the
clipping that is caused is unlikely to be resolved by
reducing signal levels. So, before you start make sure that
ALL your equipment is correctly powered and that any
suspect batteries have been checked and/or changed.
One last thing should be said before we start. It is possible
for bad cables to cause a distorted sound, even if they
passed our checks in above. The only way to check these is
individually by driving them with a 'loud' unit direct into the
amp with little else in the way. However, I should say this
may not identify them; as I have said before strange things
can happen with electronics!
Noise Elimination
53