up your sound system and it's time to connect up the amplifiers.
Where do you turn the knob on the amp? Hmm . . . 12 o'clock looks
good. Well, believe it or not, there is actually a correct position
to turn that knob to and it can be calculated.
GainSet is a computer program that does this calculation
for you. Using information you provide about your system, GainSet
will show you the gain setting for your amplifier that will provide
the highest signal to noise ratio and the "hottest"
signal you can achieve before your system clips.
do I get GainSet?
GainSet is free and you can download
it from our website. The only thing we ask in return is that you
help us make GainSet better by submitting your equipment data to
be included in a future version of GainSet.
To download GainSet, go to the download
page. You may be asked to accept a security certificate. Go
ahead and accept it. A little applet will run and determine which
installer you need for your operating system. If you are using Windows
you have the option of downloading GainSet with the latest Java
Virtual Machine included. If you already have Java
1.4.1 or higher installed on your system then you can uncheck
the option to include the VM. If you don't have Java installed or
you are not sure, download the windows installer with the VM included.
After that, just follow the instructions in the
installer and you'll be up and running in no time.
do I use GainSet?
GainSet is simple to use and will provide accurate
information as long you configure your system properly. The data
in GainSet is calculated using the following assumptions about your
You have properly set
up the gain structure on your mixing console to allow the maximum
signal to noise ratio possible for your program material.
You have properly spec'd
your power amplifiers relative to the power handling of
***If either of the above
requirements are not met, GainSet may not give you accurate
When you start GainSet you will see four selectable
menus and a graphic of a knob representing the gain knob on your amplifier.
Simply select the manufacturer of your
mixing console from the top left list and select the model number
from the list below that. Then select the manufacturer of your amplifier
from the top right list and the amplifier model number from the list
below that. The graphic of the knob will change to indicate the optimal
gain setting for your amplifier.
It's that simple! Just turn the knob
on your amplifier to the position indicated.
Remember, GainSet will tell you the
optimal gain setting for the electronics. You
may choose to waiver slightly from that if you are trying to balance
an active loudspeaker stack or
if your amplifier is too powerful for your loudspeakers. You're
the designer. GainSet will tell you where to start. You can take
it from there.
if my equipment isn't listed?
We have done our best to include equipment
definitions for as many poplular mixing consoles and power amplifiers
as possible. In some cases, we are still waiting to hear back from
manufacturers with the specifications we need to include their equipment
in GainSet. In the meantime:
your mixing console isn't listed . . .
Dig out your manual and locate the
spec for the maximum output level of your console outputs. The value
should be in dBu. In GainSet select "Other" from the "Mixers"
Manufacturer list and select the dBu level from the "Models"
list. Then visit the Submit page on our website and e-mail us the
manufacturer and model number of your console and the corresponding
max output level. We will then add it to the GainSet database and
include it in the next update.
your amplifier isn't listed . . .
You're pretty much out of luck if your
amplifier isn't listed. If you can locate the neccesary specs for
your amplifier, you could do the calculation yourself. What you
definetely need to do is locate the neccesary information and send
it to us using the instructions on the Submit page. We will then
include your amplifier in our next update.
Here is the info we need on your amplifier:
See the Submit page for more info.
if I have signal processing devices between my mixing console and my
As you can see, GainSet in its current
form is only configured to calculate gain structure for a system where
the mixing console outputs are connected directly to the amplifier
inputs. In most cases you will have signal processing devices between
the mixing console and the amplifier. We chose to only include mixing
consoles for the first release of GainSet because we felt it was more
realistic for us to anticipate what sort of mixing consoles are being
used rather than attempt to predict all the signal processing devices.
That would be a never ending battle.
However, in the next major update to
GainSet, we plan to include signal processing devices but we need
the help of GainSet users to tell us what equipment we should include.
For now, if you can find the max output level of the last processing
device in your signal chain, you can enter that in GainSet using the
"Other" option in the "Mixers" list. It is very
important that you have properly set up the gain structure of all
your processing devices relative to your mixing console in order for
GainSet to give you accurate information. There is a tool called the
ClipCop that can help you in that
When you find the max output level of
your signal processing device, go to our Submit page and let us
the manufacturer, model, and max output level of your device and
we will include it in the next release of GainSet.
does it work?
When used properly, the gain knob on
a power amplifier is used to make the incoming line-level signal match
the requirements of the input circuitry of the amplifier. GainSet
simply takes the maximum input voltage level for the amplifier and
subtracts the maximum output voltage of the mixing console. The result
is usually a negative number representing the amount of attenuation
in dBu needed to get the two signals to match. GainSet then calculates
how far the knob needs to be turned to achieve the desired attenuation.
Let's run through an example:
You have a Soundcraft K3 mixing console
with a max output level of +26 dBu. You have a QSC PowerLight 1 amplifier
with a max input level of +22 dBu. 22 - 26 = -4. So you need to turn
your gain knob on the amplifier down 4 dB from full voltage gain in
order to match the signals. If you select Soundcraft K3 from the "Mixers"
menu and QSC from the amplifiers menu GainSet will show you the following
Here is a picture of the corresponding
knob position on an actual QSC PL1:
Notice that the full voltage gain on
this amplifier is 32 dB. The position GainSet calculated corresponds
to the 28 dB position on the amplifier gain knob. 28 dB is 4 dB
less than 32 which performs the required attenuation of -4 dB we
isn't there an installer for Mac OS 9?
Apple is making it increasingly difficult to develop
new applications that will run in both OS X and OS 9. This is
true for programs written in Java. Apple abandoned Java development
on the classic Mac OS four years ago. Since GainSet uses some
technology developed within the last couple years, we are having
a hard time getting it to run in OS 9. So now is as good a time
as any to make the switch to OS X. If anyone out there is familiar
with the Java environment and would like to take a stab at getting
GainSet to run in OS 9 we'd be happy to let you take a look at
the source code.
it work for self-powered loudspeaker systems?
The same electrical principles that
make GainSet work are also applied to self-powered loudspeakers.
In the next update, we plan to include self-powered loudspeakers
but we need to know which ones to include. Follow the instructions
on the Submit page to get your self-powered loudspeakers included
GainSet is brought to you by Jason Romney and Michel
Marrano, former MFA graduates in Sound Design at the North Carolina
School of the Arts. A couple years ago we were given an assignment
in the form of a graduate research project to come up with a
solution that will demystify power amplifier gain settings. GainSet
is the result of that project.
To learn more about the Graduate Theatre Sound Design
program at the North Carolina School of the Arts you can visit the
school website or you can contact
To learn more about Jason Romney you can visit his
website at www.cd-romney.com.
If you would like to contact Michel Marrano you
can contact her here.