Daking Audio FET III User manual

Daking Audio
FET III Stereo Compressor/Limiter Manual
VERSION 1.4
Hendrik David Gideonse XIX
3/26/2010

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Safety Considerations
1. Read, follow and keep these instructions.
2. Heed all warnings.
3. Do not use this equipment in or near water. Do not place liquids on or near the
device because the device might be damaged during a spill.
4. Clean only with a soft dry cloth.
5. Do not block any ventilation openings. Install in accordance with the
manufacturer‟s instructions.
6. Use only Daking supplied power supplies to prevent damage to your device or
create safety hazards.
7. Do not install near any heat sources such as radiators, heat registers, stoves, or
other apparatus (including amplifiers) that produce heat.
8. Do not defeat the safety purpose of the polarized or grounding-type plug. A
polarized plug has two blades with one wider than the other. A grounding-type
plug has two blades and a third grounding prong. The wide blade or the third
prong are provided for your safety. If the provided plug does not fit into your
outlet, consult an electrician for replacement of the obsolete outlet.
9. Protect the power cord and all connecting cables from being walked on or pinched
particularly at plugs, receptacles, and the point where they exit from the device.
10. Only use attachments/accessories specified by the manufacturer.
11. Unplug this device when unused for long periods of time.
12. Refer all servicing to qualified service personnel. Servicing is required when the
apparatus has been damaged in any way, such as when a power-supply cord or
plug is damaged, liquid has been spilled or objects have fallen into the apparatus,
the apparatus has been exposed to rain or moisture, does not operate normally, or
has been dropped.
13. Do not overload wall outlets and extension cords as this can result in a risk of fire
or electric shock.

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Contents
1Daking Audio FET III Stereo Compressor/Limiter Manual....................................... 5
1.1 About Daking Audio............................................................................................ 5
1.2 Quick Start Guide................................................................................................. 5
1.2.1 Don‟t read the manual! ................................................................................. 5
1.2.2 Basic Set Up.................................................................................................. 6
1.3 The Audio Path and the Sidechain Path............................................................... 6
1.4 Front Panel ........................................................................................................... 8
1.4.1 In General: Rotary Switches and Potentiometers ......................................... 8
1.4.2 The Threshold Knob (-10 dB to +10dB) ...................................................... 8
1.4.3 Ratio Knob (1.5:1, 2:1, 3:1, 5:1, 10:1, 20:1)................................................. 8
1.4.4 Attack Knob (from 250 μs to 64 ms) .......................................................... 10
1.4.5 Release Knob (from 500 ms to Dual Time Constant Auto)........................ 10
1.4.6 HPF (High Pass Filter: from Off to 200 Hz)............................................... 12
1.4.7 Make-up Gain Knob (from +0dB to +11dB).............................................. 12
1.4.8 VU Meter .................................................................................................... 12
1.4.9 3-Way Meter Switch................................................................................... 13
1.4.10 Bypass Switch............................................................................................. 13
1.4.11 Link: Dual Mono to Stereo......................................................................... 13
1.5 Back Panel.......................................................................................................... 14
1.5.1 In General: XLR Connectors ...................................................................... 14
1.5.2 Line Input (XLR or ¼” TRS)...................................................................... 14
1.5.3 Line Output (XLR) ..................................................................................... 15
1.5.4 +48V DC with a 6 pin DIN connector........................................................ 15
1.6 Signal Flow: Patching Into and Out of Your FET III Compressor.................... 15
1.6.1 Mic Pre to FET III to Audio Interface or Mixer......................................... 15
1.6.2 Connecting Via a Single Insert Jack........................................................... 16
1.6.3 Via a Patch Bay........................................................................................... 18
1.6.4 Stereo Setup as a Bus Compressor for Mixing or Mastering...................... 19
1.7 Typical Uses of a compressor ............................................................................ 20
1.7.1 Why do I need a compressor anyway? ....................................................... 20
1.7.2 Keeping a vocal performance out front ...................................................... 20
1.7.3 Keeping bass consistent.............................................................................. 21
1.7.4 Fatten kick drums........................................................................................ 21

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1.7.5 Limiting to preventing overload, clipping and distortion........................... 21
1.7.6 Pointers and General Principles.................................................................. 22
1.8 Specifications..................................................................................................... 23

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1 Daking Audio FET III Stereo Compressor/Limiter Manual
1.1 About Daking Audio
Congratulations! You‟ve purchased a FET III Stereo Compressor/Limiter, a
very high end piece of gear! The FET III uses all discrete transistor Class A
circuits, THAT Corporation differential amps and printed circuit board
mounted switches. Signal capacitors are precision polypropylene or ultra low-
leakage electrolytic types. Our boards are assembled on a mil-spec assembly
line. The chassis are stainless steel for maximum RF and hum rejection and a
long lasting finish. Every unit is hand finished, tested, burned in, and tested
again in a second facility.
Also, we just couldn‟t stand to use plastic knobs, so we designed our own
anodized, engraved aluminum knobs that give a much more precise and
quality feel. We designed our gear to be gear you‟d own for life, not some
passing fancy you‟d leave in the dust once you figured what the good stuff
sounds like. This IS the good stuff.
-Geoff Daking
1.2 Quick Start Guide
1.2.1 Don’t read the manual!
Most of you will already know how to use a compressor perfectly well and
might be even a little offended at the idea of reading the instruction
manual. So don‟t read it. This manual is not for you.
This manual is for someone that knows enough to buy the very best
(Daking of course!), but doesn‟t have a lot of experience using recording
gear.
You might be a bass player who just got a DAW and wants more control
over your dynamics in your home studio. You might be a student that just
got a check from Mom & Dad and wants to go buy something nice for
yourself.
You might be the guy standing ankle-deep in a
pool of salt water, trying to yank the grounding pin
off your mixer‟s power cord so you can plug it into
your 2-prong ungrounded outdoor outlet.
This manual is especially for you!
Whenever you see the Duh! Guy, you can be
assured that most professionals will already know

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this stuff. Be sure to explain this stuff to your friends in a snotty and
condescending tone, so you too can be part of the tradition of know-it-all
engineers and recordists!
1.2.2 Basic Set Up
Your compressor can be used in a variety of different ways and patched
into the signal chain of many different set-ups. The FET III can be used
while you are tracking a microphone, while you are mixing tracks down,
and in mastering scenarios.
The FET III can be used in both dual mono and in stereo modes.
1. Patch the outputs of your line-level audio devices (like a mic
preamps or an insert send on your console) to the Line Input jacks on the
rear of the compressor.
2. Patch the Line Outputs on the rear of the compressor to the input
of your line-level audio device (like the insert return on your console)
3. Attach 6-Pin DIN cable on the power supply to the back of the
compressor
4. Plug the power supply into a grounded outlet, preferably with AC
line filtering, surge suppression and voltage regulation.
Get compressin‟!
1.3 The Audio Path and the Sidechain Path
One important concept to understand about compression is
the difference between the audio path and the sidechain
path. The audio path is the audio that is going into the
compressor, being processed by the compressor, and then
coming out of the compressor. The sidechain path is the
audio that is used to determine when and how the
compressor will behave. The simplest compressors
operate by using the audio input for both the audio path
and the sidechain path. More versatile processors allow you to alter the sidechain
audio, use a different audio source or blend two sources together. The FET III
allows you to filter the sidechain audio and to blend the audio from channels 1
and 2 together in the chain. This allows much more precise control of how the
compressor works both in mono and stereo modes.

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Figure 1 FET III Block Diagram

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1.4 Front Panel
1.4.1 In General: Rotary Switches and Potentiometers
Your compressor is equipped with both rotary switches (Ratio Control)
and with precision potentiometers. Switches make a big click when you
turn them and potentiometers offer a smooth continuously variable feel as
you rotate them.
One of the big advantages of switches is that you can reproduce the same
settings over and over again. The big advantage of continuously variable
potentiometers is that you can get all of the setting in-between the
positions on the switch. The FET III uses switches on the Ratio control so
that it is easy to use the exact same ratio on both the left and right side of
the compressor.
1.4.2 The Threshold Knob (-10 dB to +10dB)
The Threshold knob controls at what level in decibels the compressor
starts to work. When a signal goes above the Threshold, the compressor
starts to attenuate (reduce the level of) the signal. Signals below the
threshold get left alone. If the knob is set to “0,” then all the sounds above
0 dB will be reduced in gain and the sounds below will be untouched.
If you want more compression, then you should lower the Threshold. If
you want less compression then you should raise the Threshold. See
Figure 2.
1.4.3 Ratio Knob (1.5:1, 2:1, 3:1, 5:1, 10:1, 20:1)
The Ratio knob controls how much attenuation (gain reduction) happens
to the signal above the Threshold. The Ratio is a comparison of the input
to the output, when the signal is above threshold.
For instance, imagine you have set a 3:1 ratio and set the Threshold to 0
dB. Note in Figure 2 below, the audio input signal rises +9 dB above 0
dB Threshold. As you can see the output signal is only +3 dB above
Threshold. The increase of 3 dB input above Threshold yields only 1 dB
above the Threshold output.
Higher ratios are easier to hear because they are making a bigger change
from the original. So if you are trying to be subtle, stick with generally
lower ratios. Sometimes of course you will need to use heavy
compression to achieve the results that you are after.
Compressors with ratios of 10:1 or higher are called limiters. Limiters are
often used after preamps to protect recorder inputs from sudden overloads,
like intermittent screaming or someone dropping a mic during a live
recording. The limiter helps prevent the recording from being ruined!

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Limiters can also be used to set a volume limit for a playback system to
protect speakers from damage.
Figure 2 Threshold and Ratio Settings with Meter Readings

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1.4.4 Attack Knob (from 250 μs to 64 ms)
Unfortunately, the Attack knob has nothing to do with using the power
supply as a weapon or stopping the guitar player from playing too much!
The Attack knob controls how fast the compressor turns on after a signal
crosses the Threshold. If the Attack is set slow, the compressor will react
slowly to transients above threshold. If the Attack is set fast, the
compressor will react the instant the transient exceeds the Threshold. Fast
settings are to the left and slower settings are to the right. See Figure 3
below.
If you set the compressor‟s Attack too fast the transient will be attenuated
too much and the power of the instruments will be reduced. When drums
sound wimpy or flat, it is often because the Attack settings are too fast. If
you set the Attack to slow, you might miss the transients altogether and
not compress the audio enough.
If you have a lot quick explosive peaks, speed up the attack to prevent
overloads of downstream devices. If you don‟t have many fast peaks, use
slower settings to level out small dynamic changes in a vocal performance
or bass part.
Your Daking compressor is fast enough to control even the most intense
transients from drums and percussion. The fastest attack time on the FET
III is 250 μs (1/4 of a millisecond) while the slowest attack time is 64 ms.
1.4.5 Release Knob (from 500 ms to Dual Time Constant Auto)
There are NO hostages!
The Release knob controls how quickly the compressor stops
compressing after the signal drops below the Threshold. See Fig
3 below. The Release control can be used to lengthen sustain
times and to blend audio signals together. When Release times
are faster, the compression may be less obvious and be more
transparent. If Release times are set improperly the compressor
may sound as if it is causing the audio to swell, pump or breathe.
The Release time and behavior of a compressor is very important to the
signature sound of the unit. The FET III has release times that range from
about a half second to a dual time constant release based on the Audio &
Design (Recording) Limited‟s famous F760X 'Compex' limiter. When the
FET III is in full Auto mode, the release starts out pretty fast, but then
slows down. The total release time can be as long as 7-8 seconds, but dual
time constant makes it sound very natural. See Figure 3.

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Figure 3 Attack and Release Times

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1.4.6 HPF (High Pass Filter: from Off to 200 Hz)
The High Pass Filter only affects the sidechain path and not the audio
path. This means that it cuts low frequencies below the Hertz setting on
the HPF by 12 dB/Octave in the audio signal that goes through the
detection path. See Figure 1. Removing the low frequencies from the
detection circuit causes the compressor to not compress when low
frequency sounds dominant the audio signal. This allows the compressor
to avoid attenuating low sounds like kick drum and bass and still control
the dynamics of the midrange and high frequencies.
This feature is especially useful when you are using the FET III for stereo
buss compression. As you turn up the HPF knob, you will notice that it
has the effect of boosting the bass frequencies, while the mids and upper
frequencies get more controlled.
1.4.7 Make-up Gain Knob (from +0dB to +11dB)
The Make-up Gain control restores the overall level and compensates for
the attenuation of the audio signal through the process of compression.
1.4.8 VU Meter
Your compressor is equipped with a wonderful device, called a VU meter.
A VU (Volume Unit) meter measures loudness more like the way people
hear loudness: as an average of the levels over time (in this case, the last
300 ms.) Typically 0 on a VU is equivalent to -18 dBu full scale, or 18 dB
lower than digital audio systems‟ 0 dB. It is also +4dBu, the standard
operating level of professional audio equipment. Most digital recorders
and DAWs use PPM or Peak Program Meters to show the loudest part of a

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sound wave. This is really important for digital because anything that
goes above 0 dB full scale is going to distort and sound horrible.
The meter can also be used to determine gain reduction in addition to
input and output levels. When the compressor is working, the needle will
move to the left to show how much the compressor is attenuating
(reducing) the gain.
The VU meter can be switched via the 3-way meter switch to provide
metering for your input signal, your output signal or the gain reduction
that the compressor is providing.
1.4.9 3-Way Meter Switch
The meter switch allows you to change which signal you are evaluating
with the VU meter. You can choose input, gain reduction, or output. The
gain reduction setting shows how much the signal is being attenuated by
moving to the left. This meter becomes important when using
compression and make up gain to compare the before (input) and after
(output) of your audio.
1.4.10 Bypass Switch
This switch lets you choose between having the compressor turned on and
the compressor being bypassed. Bypassing is a good way to hear the
before and after of what you have done with the compressor and to hear
how good your settings are.
1.4.11 Link: Dual Mono to Stereo
Your compressor can be used as two single mono channel compressors or
linked together into a variable stereo pair. The knob controls a mono to
stereo pan matrix that blends the left and right channel sidechain signals
together. This allows the compressors of both channels to compress at the
same time and in the same way.
One important concept of the Link feature is that the audio feeding the
sidechain is the affected audio, NOT the audio that you hear. See Figure 1.

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1.5 Back Panel
1.5.1 In General: XLR Connectors
XLR connectors are more expensive, more reliable and offer a stronger
connection than ¼” TRS connectors. They also have the option of a
locking latch that helps to keep the cable from being pulled out
accidentally. If worse comes to worse, you can connect two
XLR cables together to make a longer run. The XLR connection
is strong enough that you can swing a hand-held microphone
around your head like a cowboy for quite a long time before the
mic flies off and knocks someone‟s teeth out.
XLR males are used for Outputs and XLR female are used for
Inputs. Makes sense, right? Many people confuse the male and
female XLR parts, because the female plug fits into the male
plug to join together. The male XLR has 3 pins (male pins…) inside the
plug and the female XLR has three holes inside the plug (female holes…).
Check out the diagrams below:
1.5.2 Line Input (XLR or ¼” TRS)
The line input accepts a line-level signal, not a mic level or instrument
level signal. You connect to the input of your compressor with an XLR
cable at +4bBu.
Your compressor is not expecting a microphone-level signal and
definitely not a speaker-level signal! If you want to compress a
mic signal you need to run the mic into a mic pre-amp first (a
Daking Mic Pre is a good choice!), which boosts the gain of the
signal from mic level to line level. Then you can send the output

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of the mic pre into the compressor. Plugging a mic directly into the
compressor just won‟t work. It‟s kind of like putting a PB & J into a VHS
machine: you can do it, but it‟s a bad idea.
Plugging a speaker level ¼ input into your Daking Compressor may blow
it up. This signal is far too hot to work properly with your compressor. If
you need to control dynamic range of a speaker, then compress it as a line
level, before the signal goes to the amplifier.
1.5.3 Line Output (XLR)
The output signal from your compressor comes from here. If you are
connecting your compressor to a patch bay on a console instead of a line
XLR input on another piece of gear, you will want to purchase a female
XLR to male ¼” TRS adaptor cable to make this easy. The output signal
is line level, not mic level, so patching it into a mic pre-amp afterwards is
unnecessary and probably will just cause problems.
1.5.4 +48V DC with a 6 pin DIN connector
Your FET III Compressor uses an +48V DC external power supply with a
DIN connector that is very similar to a laptop power supply. External
power supplies offer many advantages over internal power supplies like
reducing hum from 50 or 60 cycle power sources and improving the safety
of the equipment you are using. Even with the improved safety of the
external power supply we still recommend that you avoid recording in the
bathtub or swimming pools.
1.6 Signal Flow: Patching Into and Out of Your FET III
Compressor
1.6.1 Mic Pre to FET III to Audio Interface or Mixer
Nowadays most people are recording digitally into a Digital Audio
Workstation (DAW) like ProTools, Cubase or Sonar. Most of the audio
interfaces that are available don‟t have high quality microphone preamps,
so many recordists purchase outboard preamps, like Daking‟s Mic Pre
One, to ensure professional quality sound. The mic preamp and
compressor are connected inline directly into the audio interface.
Figure 5 Signal Flow for In-Line Use of FET III

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The job of the mic pre amp is to raise the level of a mic level signal to line
level so that it can be manipulated or recorded. You can‟t plug a mic into
the FET III and hope to get anything useful out of it.
Basic Cables Needed:
(2) Microphone Type Cables (Female XLR to Male XLR)
(1) Female XLR to Male ¼” TRS Balanced Cable
Here are the steps:
1. After making sure that phantom power isn‟t turned on and that your studio
monitors are muted, patch a microphone to the mic preamp with a mic
cable (XLR Female to XLR Male).
2. Patch out of the mic preamp to an input jack on the FET III, with another
mic cable (XLR Female to XLR Male).
3. Patch out of the FET III into the line input on your interface or your mixer.
Use a XLR Female to ¼” TRS Male cable. Make sure that you aren‟t
going into another mic preamp! If you do, you will likely end up with a
distorted signal.
4. Turn on phantom power (if needed) and set levels.
1.6.2 Connecting Via a Single Insert Jack
On many live and hybrid mixers, inserts are patched via a single insert
jack using a special insert cable. The insert cable for the FET III (see
Figure 3 below), often called a „Y‟ cable, consists of a ¼” TRS plug on
one side and 2 XLR plugs on the other side, one male and one female.
The tip of the TRS plug is wired to the 2 pin of the Male XLR
plug (usually the white or left plug if marked) and the ring of the
TRS is wired to the 2 pin of the Female XLR connector (usually
the red or right plug if marked.) The sleeve of the TRS plug is
wired to both pins 1 and 3.
The tip of the TRS plug is the “send” and the ring of the TRS plug
is the “return.” A really good way of remember this stuff is:
Red, Right, Returning and Ring all start with “R.”

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Figure 6 Insert Cable for Use with FET III
On the familiar RCA plugs used on home theater equipment, the red
plug is always the right side. „Y‟ cables often use the same color
scheme because usually the cable was intended to split a stereo
signal into two mono signals: left and right. When you use this „Y‟
cable as an insert cable the tip side is the send side and the ring side
is the return side. This cable is BOTH an output and an input!
Steps for Patching with an Insert Jack and Cable:
1. Patch the TRS side of the Insert or „Y‟ cable
into the jack marked “insert” on the patch bay of your mixer. If you
had signal playing through the channel at the time, this cable will
break the connection, and you shouldn‟t hear anything. If you touch
the tips of the other two plugs together, you will get signal back.
2. Plug the connector marked “tip” or “send” or
simply in white into the input connector.
3. Plug the connector marked “ring” or “return”
or that is in red into the output connector.

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1.6.3 Via a Patch Bay
In most professional setups, processors are racked and then installed as
part of a patch bay system. This makes it easier to make connections,
because you don‟t need to go behind the rack to plug and unplug cables.
Patch bays are usually made up of modules with 2 jacks in the front, one
over the other, and two jacks (or solder terminals, or DB25, etc) on the
back. For the sake of this manual, we‟ll assume you‟re using a ¼” TRS
patch bay with jacks on the front and back.
You do not want to normal the inputs and outputs from the compressor to
each other. This will create a feedback loop. Converting a half-normal
module to a non-normaled module is sometimes as simple as rotating the
module in the patch bay. See the manual for your patch bay.
Cables Needed:
(1) XLR Male to ¼” TRS Male
(2) XLR Female to ¼” TRS Male
Steps:
1. Patch from the bottom back jack on the patch bay module to the input
on the FET III using the ¼” TRS to XLR Male cable.
2. Patch to top jack of the patch bay module from the output of the FET
III using the XLR Female to ¼” TRS cable.
3. Now you can patch into the compressor from the front of the patch
bay. Simply run a patch cable from your source and into the bottom

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jack on the module and then run from the top jack on the module to
wherever the signal needs to go.
1.6.4 Stereo Setup as a Bus Compressor for Mixing or Mastering
The purpose of the Stereo Link mode for bus compression is to make sure
that both compressors compress in unison. This prevents the stereo image
from shifting to the left or right when one side of the stereo field is
compressed and the other side is not because of a big sound on only one
side of the stereo mix.
Stereo bus compression should used in a subtle way because aggressive
compression in stereo tends to create undesirable artifacts. Bus
compression is most often used to unify a mix into a cohesive whole and
to control dynamics of an entire mix allowing loudness to be maximized.
Steps:
1. Connect both sides of the FET III to the left and right sides of the
program respectively.
2. Insert the compressors, or connect them inline as shown above.
3. Turn the Link knob all the way to Stereo Link.
4. Set both sides of the compressor to the same Ratio, Attack and
Release, and then adjust the Threshold on both sides so that the meters
show the same amount of Gain Reduction on both the left and right
sides. You may find that Threshold controls may not look like they
are in the same position even when they sound like they are balanced.
This is normal because the audio on either side of the mix is not the
same.
5. Switch your meter to monitor the Output Level and verify that both
sides of the mix are still in balance. Make adjustments to the threshold
controls if they are not in balance. Turn the Threshold down on the
side that has too much level or turn the Threshold up on the side that
has too little.
6. After you have balanced the left and right sides you can adjust the
Output Gain to get the level that you desire.
7. Experiment with “in-between” settings of the Link knob and various
permutations of the Attack and Release settings.
Tip for setting the compressor in Stereo Link:
1. Change the bus you plan on compressing into a mono pair, either by
adjusting pan controls or engaging the “mono” button on your console.
(Note: You can also send a test tone as two mono signals to both sides
of the compressor)

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2. Set the Ratio, Attack and Release to the same setting on both sides and
then adjust the Threshold controls so that both sides are showing equal
Gain Reduction and equal Output levels.
3. Return your bus back into stereo and both sides will be balanced
equally.
1.7 Typical Uses of a compressor
1.7.1 Why do I need a compressor anyway?
Compressors help to control the dynamic range of audio signals. The
dynamic range of an audio signal is the difference between the quietest
part of a signal and the loudest part of the same signal over the course of
the entire song or program. Compressors reduce this difference between
loud and soft (signal dynamic range) to keep things more consistent from
start to end. In a nutshell, a compressor allows you keep an element of a
mix at the level you choose relative to all the other signals you are mixing.
Without compression, the guitar solo might fall into the background or the
drums might over take the vocals!
1.7.2 Keeping a vocal performance out front
Compression is THE way to get a vocal performance to stay out front and
stand out in the mix. The compressor reduces the difference between the
singer‟s loudest notes and softest notes to make it more consistent. This
same idea works also with background vocals to keep them from rising too
far out front. A great starting point for vocals is:
Parameter
Value
Threshold
0 dB
Ratio
5:1
Attack
1 ms
Release
Auto
Make-up Gain
+6 dB
If the vocalist is extremely aggressive you may need to speed up the attack
time (how fast the compressor turns on after threshold is exceeded) to
control the transients on plosive consonants like “P,”, “T,” “D,” “B”, “C,”
and “K.”
If the vocalist is extremely dynamic you may need to increase the Ratio
(increase the compression above the threshold) and/or reduce the
Threshold (initiate compression at lower levels).