Softube fet compressor User manual

©2008 SOFTUBE AB, SWEDEN. ALL PRODUCT AND COMPANY NAMES ARE TRADEMARKS OF
THEIR RESPECTIVE OWNERS. AMP ROOM IS A REGISTERED TRADEMARK OF SOFTUBE AB,
SWEDEN. SOFTUBE IS A REGISTERED TRADEMARK OF SOFTUBE AB, SWEDEN. ALL
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE. ALL RIGHTS RESERVED.
2

Table of Contents
Contact Details..................................................................................4
Support.................................................................................................................4
Installation and Authorization.........................................................5
Introduction.......................................................................................6
User Interface....................................................................................8
Input......................................................................................................................9
Ratio...................................................................................................................10
Attack and Release............................................................................................11
Input and Gain Reduction VU meters...............................................................12
Output.................................................................................................................13
Output Peak Meter.............................................................................................13
Detector Controls...............................................................................................14
Parallel Inject......................................................................................................18
Status Indicators................................................................................................19
Controls Summary..........................................................................20
Tweaking Tips.................................................................................21
Multi-Channel Operation................................................................23
Block Diagram.................................................................................24
System Requirements....................................................................25
All Versions........................................................................................................25
Native Version (VST/AU/RTAS) .......................................................................25
Pro Tools|HD Version (TDM/VENUE)...............................................................26
3

Contact Details
If you would like to get in touch with Softube, please e-mail [e-mail].
Alternatively, you could use the phone or send an old-fashioned mail (do you remember
envelopes, stamps and paper?) to:
Softube AB
S:t Larsgatan 10c
SE-582 24 Linköping
Sweden
Web: www.softube.com
E-mail: [email protected]
Phone: [phone] (9 am – 5 pm CET)
Support
On the Softube website (www.softube.com) you will find answers to common questions
(FAQ) and other topics that might interest you.
Support questions can be posted at http://www.softube.com, where we will help you as fast
as we can!
4

Installation and Authorization
I F Y O U B O U G H T T H E P R O D U C T I N A B O X you will have to register it in order to
transfer the license to your iLok account:
1. Go to http://www.softube.com/register to transfer the license to your iLok
account. You will need the License Code found in the box, your iLok.com
User ID, and your iLok USB dongle. Follow the instructions on the web page.
I F Y O U B O U G H T T H E P R O D U C T O N L I N E and have got the confirmation e-mail, the
license will already be deposited in your iLok account:
2. Make sure that you have the latest iLok drivers installed. They can be found at
http://www.ilok.com.
3. Log on to http://www.ilok.com and transfer the newly received license to your
physical iLok dongle.
4. Install the software from the CD, or download the latest version from
http://www.softube.com/installers.
Sometimes the CD contains installers for all Softube products, but you will only be able to
run those that you have acquired licenses for. In some cases, extra demo licenses are
included when you buy a Softube product.
5

Introduction
T H E F E T C O M P R E S S O R I S B A S E D O N the most famous hardware FET compressor,
and very much effort has been spent modeling the real hardware to make sure that this one
sounds exactly the same. If you only use the big knobs and the six fixed ratios you'll get
exactly the same analog sound and functionality as the real deal. But that's just the
beginning. With the help of digital technology we have added some useful features that still
have that analogue sound – but features that would've been hard or even impossible to
implement with analog electronics. That way you will be able to get the best of two worlds.
(Not even mentioning how ridiculously many FET Compressors you will be able to fit into
your project without running low on CPU.)
Not convinced yet? Set the Input on M A X , Ratio on A L L . Listen.
6
Figure 1: The user interface of the FET Compressor – an analog sounding
compressor with digital features.

Design Philosophy
T H E R E A R E T H R E E M A I N I D E A S B E H I N D T H I S D E S I G N : First of all, we wanted to
make an analog sounding digital compressor. Nothing must stand in the way of the sound.
Every single part of the simulation contributes to making this piece unique. The extremely
fast attack, all the subtle (and sometimes not so subtle) distortion that comes from the
different parts of the compressor and the extremely careful way the signal is handled and
conditioned through out the signal chain.
Second, we added features to make this product even more versatile and unique. The
enhanced ratio, parallel compression, detector filtering and lookahead are such features.
Third, these features must not stand in the way of the usability. The fewer knobs the better,
and the faster the user gets the sound they want, the better.
This boils down to a single main objective: Every user should be able to get a good sound
within seconds, and no user should be afraid to mess up the sound. An amateur should be
able to make this sound just as good as a pro. And yeah, it has to look good.
In order to achieve these objectives we had to put special effort into the modeling. The
original hardware has some quite quirky circuits, and a lot of its sound comes from far from
ideal components and design. A lot of new ideas were developed during the modeling, and
with the help of our expert listener and “golden ears” Dan Lumbye, we managed to put
together a piece of software that should please even the most critical ears.
Patents
This product is protected by patent SE525332 and patents/patent applications
US2004-0258250, EP1492081 and JP2004-183976.
7

User Interface
T H E C O N T R O L S O F the FET
Compressor are divided into two sections.
First of all we have the big knobs (Input,
Ratio, Attack, Release and Output),
which are the knobs that you will use
every time you use the compressor (top
row in the illustration on the right). These
knobs are pretty standard and you
probably already know what they do.
Then we have the small guys (middle
row), which don't have to be tweaked
every time you use the compressor. You
don't even have to feel bad if you never
touch them. People have managed to
make hit records for 40 years without
them. Nevertheless, they are extremely
useful, and soon you'll have a hard time
understanding how you ever could've
managed without them.
In addition to this, we also added some metering so that you can monitor your signal all the
time (bottom row). An input VU meter (which is fun to drive into the reds all the time) and a
stereo output peak meter make sure that you always know what is going on with your
signal.
8
Figure 2: Top: Knobs and meters used under
"normal" operation. Middle: Extra functionality
added in the software version. Bottom: Extra
meters added to the software version.

Input
The Input knob on this compressor works both as a gain control and a threshold control. If
you increase the Input volume you will also increase the gain reduction, which makes it
work sort of like a combination of a gain knob and a reversed threshold knob. You can drive
the I N P U T V U far into the reds without any unwanted digital clipping. Just make sure that
the O U T P U T P E A K meter doesn't indicate any clipping. (If it does, just lower the Output
volume a bit.)
The Input knob also works as a threshold control. More input gain will give
you more gain reduction.
If you drive the input
volume so that the VU
start hitting the reds
you will also add more
distortion to the signal.
If you want lots of
distortion we really
recommend you to
also set the Ratio knob
on ALL.
More input gain also means more distortion (in a good way).
9
Figure 3: The Input knob and corresponding input VU
meter.

Ratio
At a first glance, the Ratio knob on the
FET Compressor seems to work a little bit
different than its hardware counterpart. The
biggest difference is that the Ratio knob is
continuous, meaning that it's possible to
select settings between different fixed
ratios, for instance between 12:1 and 20:1.
Furthermore, it's also possible to select
settings between 20:1 and the famous “All
buttons in” setting.
If you would rather use the “pre-defined” settings that are
identical to those on the original hardware: 1 : 1 , 4 : 1 , 8 : 1 ,
1 2 : 1 , 2 0 : 1 and ALL, just click on the labels to jump directly to
those settings (see Figure 5).
“All Buttons In Mode
The A L L mode is a peculiarity found on this type of compressor.
Originally the different ratios were selected with push buttons,
which made some mix engineers try out what happens if you
press all buttons at once. From a technical perspective, pushing
all buttons at the same time makes all bias levels go berserk. From a sound perspective,
this means that you will get a very pumping compression with lots of distortion. This mode
is often called the “British mode”. By setting the Ratio somewhere between 2 0 : 1 and A L L
you'll get a sound that's definitely unique for this product.
10
Figure 4: The Ratio knob.
Figure 5: Click on
the labels to
immediately go to
a “factory” setting.

Attack and Release
Use the Attack and Release controls to change how fast the compressor starts to
compress (Attack) and how fast it should recover from the gain reduction (Release). The
attack time on this unit is very fast,
ranging from about 20 µs at the
fastest setting to about 800 µs on
its slowest setting. Other kinds of
compressors often have much
slower attack times. In comparison
to the attack time the release times
are much slower – ranging
between 50 ms and 1.1 s. Please
note that these numbers only give
a general idea of the attack and
release times. In practice (and just like in the modeled hardware), the attack and release
times will be program dependent, ie. depend on the characteristics of the input signal.
Since a fast attack and release time leads to a fast gain reduction, sometimes
those settings will cause unwanted “clipping effects”. To remove this
unwanted side effect, you can either slow down the release time or add some
look ahead to the detector circuit. (See “Lookahead”).
11
Figure 6: The Attack and Release knobs.

Input and Gain Reduction VU meters
The Input VU meter is used to monitor the input signal. If a stereo signal is present, the
meter will display the maximum energy of both signals. This may seem like a drawback, but
since the gain reduction circuit (a.k.a. “detector” or ”side chain”) works in mono, the VU will
actually display the same thing the detector sees. (Unless you start fiddling with the small
knobs, but we're not there yet.)
The Gain Reduction meter is used to monitor the amount of gain reduction in the
compressor. The FET Compressor has only one detector, so if a stereo signal is present
the gain reduction will be the same for both channels. This prevents unwanted distortion of
the stereo image.
If the Ratio knob is set at ALL, the Gain Reduction meter won't show the same results as
the original hardware. Instead it will display the actual gain reduction (which the original unit
doesn't). You will also notice that the Gain Reduction sometimes display positive values
when the Ratio is set at ALL, which is correct. The A L L mode does indeed have negative
gain reduction (=positive gain) for some settings.
12
Figure 7: The Input and Gain Reduction VU meters are also modeled using
physical modeling so they will also react just like the real thing.

Output
In comparison to the Input knob, the Output knob doesn't do much more than just
adjusting the output volume. Keep a close look on the O U T P U T P E A K meter while
adjusting the output volume to avoid unwanted digital clipping. It is good practice to keep
the levels below 0 dB, even if you are using a
(native) host that allows level above 0 dB. On
TDM, the plug-in will digitally clip all signals
above 0 dB on the output.
Output Peak Meter
The output peak meter is a fast peak meter
with hold values. Single peak values up in the
reds (at 0 dB) are okay, but don't push it. This
meter will display the left and right channel on
the left and right meter if you use the plug-in
in S T E R E O mode, otherwise it'll just show the same M O N O signal on both meters.
Keep the output levels below 0 dB!
13
Figure 8: Output knob and output
meter.

Detector Controls
The most important part of any compressor is the detector. It is the detector that decides
how the compressor should compress. All controls except the Output (and Parallel Inject)
control the detector, but in this plug-in we have chosen to bundle the four advanced knobs
together and call them “detector controls”.
Common to all these controls is that they can be turned off by setting them in the O F F
position. Their status LED will light up when ever they are active.
Don't be afraid to keep these controls in the O F F position. Use these controls
if there is something particular that you'd like to achieve or something that
needs to be fixed. (If it ain't broken, don't fix it!)
14
Figure 9: The four advanced detector knobs.

External Side Chain
In some plug-in formats, such as RTAS, TDM and AU, it is possible to use an external
signal as input to the detector.1This is very common if you for instance want to compress a
bass line using the bass drum as the trigger to the compressor. In that case, the bass line
will be compressed when ever the bass drum is hit.
Even if an external side chain signal is present, you
will have to activate the external side chain by
increasing the External Side Chain knob until the
LED lights up. If the External Side Chain knob is
in its O F F position, the detector will always use the
regular input.
Use the External Side Chain knob to set the input volume of the external signal (for
instance the bass drum track). A higher input volume will lead to more gain reduction, just
like the Input knob works without an external side chain.
Monitor the Gain Reduction VU Meter when you set the level of the external
side chain. Just increase the External Side Chain until you get enough gain
reduction.
1) External side chaining might also work in some VST hosts. It depends very much on which VST
host and version you are using. The plug-in will add two extra inputs (inputs 3 and 4) and regards these as
the external side chain input. If your host accepts these four inputs, the external side chain indicator
(Figure 15) will light up.
15
Figure 10: The
side chain knob.

Low Cut and High Cut
The Low and High Cut can be used
to filter the signal before it reaches
the detector. A good practice can be
to remove some of the (unwanted)
low frequencies so that they don't
affect the gain reduction. Another
trick is to apply filtering so that only
certain frequencies cause the
detector to compress the signal. If
you for example compress a drum kit, you might want to keep the boominess of the bass
drum, but compress the cymbals and snare. Set the Low Cut to 200-300 Hz so that the
bass drum will get filtered out before it reaches the detector.
Please keep in mind that Low Cut and High Cut don't alter the direct signal, just the signal
that enters the detector.
Please note that the 200 and 1000 Hz settings on the Low and High Cut
knobs corresponds to the knob being set at 12 o'clock (where the little
indicator lines are located). The easiest way to get to that setting is to click on
the 2 0 0 or 1 0 0 0 label on the panel.
16
Figure 11: The Low and High Cut
knobs.

Lookahead
The Lookahead can be used if the fastest attack time isn't fast
enough, for instance if you want to apply some heavy limiting to
a signal. The Lookahead will delay the signal path outside of
the detector by up to 1 ms, leaving the detector signal
unaffected. This has two effects:
1. The output signal will be delayed by up to 1
millisecond.
2. The detector will “see” the undelayed signal, but reduce the gain on the delayed
signal. This means that the detector will be able to compress the signal before
the actual transient comes (since the actual transient has been delayed).
The Lookahead time corresponds to the total latency of the plug-in. The plug-
in will not report this latency to the host, since almost no hosts support
compensating for a delay that depends on a parameter.
Some very fast Attack/Release settings will cause a “crackling” sound on transients, often
sounding like some sort of digital clipping or saturation somewhere in the signal chain. This
is very typical for this kind of compressor, but is usually an unwanted effect. The normal
way to get rid of this “side effect” is to slow down the attack and release times but now you
have another tool to use. By adding a little lookahead to the detector, many of these side
effects can be avoided.
17
Figure 12: The
Lookahead knob.

Parallel Inject
Parallel Compression is a technique where you blend the
compressed signal with the original signal. Say that you have
a heavily compressed drum track where all the transients
have been lost (compressed). By adding a little bit of parallel
compression you can blend in the original signal (with the
original transients) with the high-energy compressed signal
(without transients) and thus get the best of both worlds.
This is a technique that is very easy to achieve with a send-
bus, but this baby does a little bit more than that. First of all, you won't get any problem with
the Lookahead since the dry signal is delayed with the same delay time as the
compressed signal. Then the dry signal will be affected by the same analogue modeling
mojo as the compressed one, which means that some of the distortion and coloring of the
compressor will also have a an effect on the dry signal. And at last, the Output Peak meter
will of course show the sum of these signals, so that you can set a proper output level.
Whenever you change the gain reduction (for example by changing the Input
volume) you will need to change the Parallel Inject since the volume of the
compressed signal has changed. But be careful - sometimes the dry signal is
much louder than the compressed signal!
18
Figure 13: Parallel
compression is fun.

Status Indicators
The FET Compressor comes with a couple of handy status labels, located in the VU meter
section.
Remote (Pro Tools only)
Whenever automation is used, or if an external control
surface is connected, the Remote status indicator will
light up. The knobs that are being controlled will also
get a thin frame around them.
External
This indicator displays when an external side chain is
present. Whenever an external side chain is present, it
is possible to use the External Side Chain knob to set
the amount of gain of the external signal to the
detector.
In TDM/RTAS it will light up whenever you have
connected a side chain bus to the plug-in. This
indicator will always be lit in hosts that use the Audio
Unit (AU) format. In VST, it will light up if the host
accepts side chain inputs, but this doesn't work for all
VST hosts... So it goes.
Stereo
The Stereo indicator lights up if the compressor was instantiated in stereo mode.
19
Figure 14: Remote is lit up on
automation or external control
surfaces.
Figure 15: External is only
used in Pro Tools and Stereo
is pretty self explanatory.

Controls Summary
The knobs are controlled by either dragging Left-Right or Up-Down, or by using the mouse-
wheel.
Mouse
•Up/Down: Increase/Decrease the setting of a knob/switch
•Left/Right: Increase/Decrease the setting of a knob/switch
•Mouse wheel (Mac OS X only): Increase/Decrease the setting of a
knob/switch
Pointing over a label will make the cursor change to a “pointing hand”
cursor. Clicking the label will make the knob to immediately move to the
corresponding position.
Keyboard Commands
Use these key commands while changing a parameter.
•Fine Adjust: Command (Mac) or Ctrl (Windows)
•Reset to Default: Alt
•Automation Control Window (Pro Tools only):
Ctrl+Command+Alt+click (Mac) or Ctrl+Windows+Alt+click
(Windows)
•Show Automation Track (Pro Tools only): Ctrl+Command+click (Mac) or
Ctrl+Windows+click (Windows)
20
Figure 16: Top:
Click-and-drag
cursor. Bottom:
Label-click cursor.