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CompIQ STELLA Pro Compressor Pedal for Guitar & Bass

249,00

CompIQ Stella Pro is a full-featured compressor/limiter pedal that provides an unprecedented amount of control through its many parameters.

Sound On Sound - Review - July 2020 IssueThe Stella is, essentially, a studio VCA compressor in a pedal. It can sound wonderfully transparent, or full of character, and there’s oodles of control at your fingertips.

Compressor Pedal Reviews - CompIQ StellaI’m not aware of any compressor on the market that packs this much punch in terms of functionality. In many ways the Stella has raised the bar for compressor pedals.

Gitarre und Bass Magazine - Test Review - June 2020 IssueIt’s amazing how many options Becos FX has put in these boxes. It is hard to find real alternatives with so much flexibility in one device.

Vintage Guitar Magazine USA - VG Approved Gear Review - May 2020 IssueThe CompIQ Stella has a ridiculous amount of power. Better still, it’s a transparent compressor that only colors the tone as much as you allow it.

Guitar Magazine UK - Editor's Choice Review - September 2019 IssueNotes are thickened without thumping, and chords gel together in a way that makes you sound like a better player. This is a proper gem.

Packed in a small-sized and road-worthy black-powdered aluminum enclosure, the highly performant and versatile CompIQ Stella is the smartest addition to any pedalboard, small or big. It can be used in any studio usage scenario, including bus compression and tracking, and it performs admirably on stage. Designed with bass and guitar in mind, it is excellent with any other instrument (keyboards, synths, electro-acoustic guitars or other instruments, etc.), and also with vocals or anything else, really, with an appropriate pre-amp.

DITOS – Optional Transformer-Coupled Balanced Output DI Board for CompIQ Stella Compressor PedalA transformer-coupled balanced output DI board is optionally available for the CompIQ Stella. The DITOS allows for direct to interface recording, FOH connection from a distance, or simply for bringing in a complementary new voice to your instrument, with tight and punchy lows, enhanced low-mids, and warm-ringing highs.

 Manual
 Setting examples & sound demos
 Video demo | More
 What people say
 CompIQ 101
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Note! A good understanding of audio compression is normally required to optimally set the CompIQ Stella for live performance or studio recording. The switches are fairly small for large hands, but, since they are not to be used very often, we traded their placement inconvenience for adding more compression controls in such a small box.

Handbuilt to order. Estimated assembly time: 4-6 working days.

SKU: CIQ-5 Categories: ,

Studio-level audio performance in a pedal format

The CompIQ STELLA Pro Compressor is an all-analog externally powered or battery-operated compressor pedal designed for guitar and bass and hand-built around the top-class 4320 THAT Analog Engine®. The amount of control it offers is staggering and probably never before seen in a compression pedal, especially of this size. We didn’t leave out anything that helps to bring out a truly clean, accurate, and transparent compression. At the heart of processing, a true RMS-level detector measures the input signal and applies accurate feed-forward compression through a transparent sounding, high-performance Blackmer® VCA.

Becos Effects CompIQ Stella Pro Compressor with optional DITOS DI Board – Block Diagram

With so many controls, one may wonder how can this be tamed and furthermore, properly used in a live setup. Don’t let yourself be overwhelmed. We provided sufficient options not only for in-depth control but also for making things easier. For instance, with the flip of a switch, you can take out the Manual Attack & Release controls (the most daunting of the art of compression) and let the Dynamic Auto Timing analog circuit do the right thing for you. Two choices are available, Fast or Slower timings, and both respond gracefully to any playing style. In both settings, transients are handled faster while steady signals benefit from longer release timings. Faster timings present a more accentuated compression feel and are well suited for peak limiting.

The manual control of Attack and Release timings will expand the compression flavors by an order of magnitude. To mention just a simple trick: delay the attack time a little while bringing back a faster release time and you will end up with a punchy and proper sound for country chicken pickin’ or for instrumental stand-out soloing. Combine this with the Side Chain Filter and the X-EQ and increase your options even further. All these together will also remind you of an optical-soul type of compression, demonstrating the tremendous versatility of this pedal.

The full-scale Ratio (1:1 to infinite:1), the instrument to line-level Threshold (-40dB to +10dB) range, and up to +20dB of Makeup Gain, all in continuous controls, add to the plethora of switchable options to further attain the ideal compression for any musical program.

A Dry/Wet Mix allows for parallel compression (a.k.a. the New York style), where the desired amount of unprocessed input signal is mixed with the compressed signal, for a more natural effect application.

CompIQ Stella - Guitar Magazine Gear Of The Year 2019 Nominee BadgeThe Stella – the brand’s flagship compressor for bass and guitar – is the perfect embodiment of the company’s spirit. Apart from your regular controls like ratio, threshold, attack, release and gain make-up, the Stella also has toggle switches for the side-chain filter, Tilt EQ, and knee. While there’s a lot going on with this pedal – it has nine knobs, seven LEDs, and four switches – it’s a lot more intuitive than it seems. WE SAID Small, but packs all the features of a VCA compressor, and the same audio quality too.

Additional features are available for the very demanding players. The Side Chain Filter has three selectable options – Normal, Low, and Deep -, very helpful for bass instruments or when a fuller output is needed. To keep things simple, set the filter to Normal and the compressor will just act naturally in most instances. The Normal side-chain processing presents a non-linear, high-pass characteristic above 1KHz, which balances the potential trigger-difference between the energy of low and high frequency. Such a feature is usually available only in high-end studio compressors, and it is intended for a natural effect application even on higher compression ratios. If lower-frequency notes trigger compression yet too fast, then the Low (-12dB@90Hz) or Deep (-12dB@200Hz) high-pass filters will slightly delay the compression, freeing up the low-end just enough for the spectrum to breathe out and prevent the early or over-compression of highs.

The Compression Knee can be selected between Hard and Soft, each option having its own sonic signature. Hard Knee compression acts fast and squishes hard. Use this if you aim for peak limiting or in-your-face compression effect. Soft Knee compression acts progressive and gentle, helping to create a transparent effect application, even at the highest ratio.

The X-EQ equalization circuit dawned in the 70′ Hi-Fi era, has two selectable options for its pivot frequency: High (at 1KHz) proper for guitar and Low (at 330Hz) suitable for bass. This is a post-compression applied correction that can be either necessary for voice compensation from one instrument to another, or desired, for your particular sonic signature.

On top of all these, we added an analog Saturation circuit that can add harmonic distortions to the dry line (only), which can then be mixed with the compressed wet line, for precise balancing of the effect. This circuit rivals the vintage studio tape-overload compression effect which was a studio recording trick during the ’60s. Tape saturation is a pleasing sort of distortion arising when high amplitude audio signals are recorded on magnetic tape.

The Saturation control can vary in intensity from nothing to mild and up to warm overdrive. The result is either subtle, adding richness to the sound peaks, or obvious, with a tube-like screaming distortion feel. If needed, Low and High-frequency cut filters can be engaged by removing two internal jumpers. This helps eliminate low-frequency fuzziness or prevent high-frequency from sounding too harsh. The auxiliary Level control on the dry line will compensate for the volume loss introduced by a higher saturation setting. This parallel processing is delicately brought together and leveled up with the Mix blend knob. The parallel tape saturation feature also transforms the CompIQ Stella into a compression-overdrive effect.

An 8-LED compression display indicates the amount of effect applied to the input signal (or gain reduction), providing visual feedback over how much the sound is processed.

Pristine audio processing

The CompIQ series of compressors is not gonna alter the magic voice of your instrument. They preserve the original guitar or bass tone while providing unobstructed, pristine audio compression. The high dynamic range of these compressors allows for natural-sounding clean tones and low noise, artifact-free audio processing without the distortions introduced by many other compressors.

DITOS • Transformer-Coupled Balanced Output DI Board

DITOS – Optional Transformer-Coupled Balanced Output DI Board for CompIQ Stella Compressor Pedal

DITOS – Optional Transformer-Coupled Balanced Output DI Board for CompIQ Stella Compressor Pedal

An optional DI board is available for insertion in the space usually used for the 9V battery. The DITOS board provides a transformer-coupled balanced output in 1/4″ TRS format that is suitable for direct recording or for sending the signal to a mixing console. It can also be used as an unbalanced floating output to send the signal to another pedal or amplifier. When Stella is in bypass, the signal still passes the DITOS DI, so this may account for an active compression bypass (as opposed to the main output which will be true bypassed).

Although the unbalanced main output and the transformer balanced output may be used at the same time, the latter is phase-reversed. You may use the latter with a cable with hot/cold wires reversed if you want to use both outputs at the same time. Ground-lift jumpers are available internally for dealing with potential ground loop noise issues.

The DITOS board comes pre-installed if ordered along with the CompIQ Stella. If ordered separately, you must drill the enclosure yourself for the output connector. A drilling template is available on request. The interconnection to the mainboard is made through an internal 4-wire connection. The DITOS board can only be used with CompIQ Stella’s manufactured after September 2021.

The transformer output works exquisitely well to complement the Burr-Brown signal conditioning in the main circuit. The tone is filled with natural warmth, rendering tight and punchy lows, enhanced low-mids, and warm-ringing highs.

DITOS sound demos

Sound demos on bass 

Sound samples courtesy of jazz artist Jean-François Untrau from France. Alternating compressor Bypass and On. Click the Settings Examples tab above for details on the settings used.


Key features

  • True analog bypass
  • Blackmer® VCA analog compressor
  • Optional DITOS board for transformer-coupled balanced output (10KΩ impedance)
  • True RMS-level detector
  • Ratio 1:1 – inf:1 (limiter)
  • Threshold -40dB to +10dB
  • Make-up Gain -6dB to +20dB
  • X-EQ with selectable frequency pivot 330Hz/1KHz
  • EQ bypass – jumper selectable
  • Manual Attack 0.12 – 12 ms/dB
  • Manual Release 1.2 – 120 ms/dB
  • Soft/Hard compression knee
  • Manual timings or Fast/Slower dynamic auto attack and release timings
  • Normal/Low/Deep side-chain filter
  • Dry/Wet mix
  • Tape Saturation on the dry line with Level compensation and Low/High-frequency cut filters (jumper selectable)
  • 8-LED compression display
  • Socketed hi-quality FET audio IC, low tolerance parts, and WIMA or KEMET audio capacitors
  • Genuine Hammond black-powdered aluminum enclosure
  • Runs on standard 9V internal battery or 9-12 V DC external power supply (not included), center negative, 12mm long barrel plug
  • 3-years warranty (direct to manufacturer, international, transferable)

More info

 Manual
 Setting examples & sound demos
 Video demo | More
 Compare compressors

Weight0.4 kg
Dimensions11.2 × 6.8 × 5 cm
Technical Specifications

Input impedance: 1MΩ
Main unbalanced output impedance: <100Ω
Optional DITOS transformer-coupled balanced output impedance: 10KΩ
Ratio: 1:1 to inf:1
Threshold: -40dB to +10dB
Make-up gain: -6dB to +20dB
0dB Referrence Input Level: -20dBu (77.5mV)
Total amount of compression: usually 20dB for -20dBu (77.5mV) input level; 36dB for +4dBu (1.23Vrms) input level, all at inf:1 Ratio
Dynamic Auto Attack time: ~7ms in Fast setting; ~15ms in Slower setting
Dynamic Auto Release time: ~70ms in Fast setting; ~220ms in Slower setting
Dynamic Timing: transients are handled faster; steady signals are handled slower
Manual Attack range: 0.12 to 12ms/dB
Manual Release range: 1.2 to 120ms/dB
Side-chain high-pass filters: Normal (non-linear, easy-slope, high-pass above 1KHz), Low (additional -12dB@90Hz), Deep (additional -12dB@200Hz)
THD: <0.1% 1kHz, 0dBu in/out, 600Ω load, 24KHz BW, 12VDC power, through 6th harmonic
Max Input Level: +10dBu
Max Output Level: +12dBu
Frequency response: -2dB @ 40Hz; 0dB in between 100Hz and 22KHz
8-LEDs Gain Reduction Display: calibrated for -20dBu reference input level
Internal battery operation: 9V (6F22) alkaline battery recommended
Voltage Range: 9-12VDC, center negative [ – ], power supply not included
DC Power Plug Barrel: Ø 5.1/2.1mm, 12mm long
Current consumption without DITOS board: < 35mAh @ 9VDC; < 44mAh @ 12VDC; < 63mAh @ 18VDC
Current consumption with DITOS board: < 43mAh @ 9VDC; < 52mAh @ 12VDC; < 72mAh @ 18VDC
Product weight: 0.26Kg
Shipping weight: 0.40Kg

COMPIQ 101

The CompIQ series of compressors
Circuit Design
Dynamic Processing
Analog Engines®
Control Element
Side-Chain Detection
Side-Chain Filter
Side-Chain Frequency Compensation
Adjustable Input Level
Input Clipping LED
Balanced Output
Crossover
Compression Ratio
Threshold
Dynamic Auto Timing
Attack Time
Release Time
Make-up Gain
Compression Knee
EQ
EQ Bypass
Dry/Wet Mix
Saturation
Saturation Filters
Compression Display
9V Battery Operation
DC Power Range
Current Consumption
More Info
Compressor / Limiter
Dual Band / Stacking
2
Blackmer® VCA
True RMS-Level Sensor
Normal / Low / Deep
lows only
YES
-9dB to +6dB
> +6dBu signal levels
-
Linkwitz–Riley
70Hz to 1KHz
1:1 to inf:1
both bands
-40dBu to +10dBu
both bands
Auto Fast / Slower
both bands
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
both bands
Hard / Soft
both bands
Through Make-up Gains on Wet line (boost/cut)
-
YES
On Dry Line
adjustable
Lo / Hi Cut filters and Level controls
6-LED
both bands
-
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 69mAh @ 9VDC
< 110mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
True RMS-Level Sensor
Normal / Low / Deep
YES
-
-
Transformer Balanced / Floating
with optional DITOS DI board
-
1:1 to inf:1
-40dBu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
Manual: 0.12 ms/dB to 12 ms/dB
F / S: 70ms / 100‐220ms
Manual: 1.2 ms/dB to 120 ms/dB
-6dB to +20dB
Hard / Soft
X-EQ +/-6dB with Low / Deep frequency pivots
Effect Hardwired ON
YES
On Dry Line
adjustable
Lo / Hi cut filters
(inside jumpers)
8-LED
YES
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 35mAh @ 9VDC
< 63mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
True RMS-Level Sensor
Normal / Deep
YES
-
-
-
-
1:1 to inf:1
-40dbu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
Hard / Soft
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 15mAh @ 9VDC
< 23mAh @ 12VDC
Compressor
Single Channel
1
Blackmer® VCA
True RMS-Level Sensor
Normal
YES
-
-
-
-
1:1 to inf:1
Lo: -40dBu / Hi: -30dBu
Auto Slow
12ms
220ms
-6dB to +20dB
Hard
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 15mAh @ 9VDC
< 23mAh @ 12VDC
MINI Pro vs. other minions
Do you want to know more about mini compressor pedals? We compiled a Technical Shootout for most performance and popular mini compressor pedals available. Click here to find out how CompIQ MINI Pro stands out.

Blackmer® VCA
First developed by David Blackmer of dbx Inc., the original dbx 202 “Black Can” VCAs can still be found in operating consoles today. These first VCAs suitable for pro audio equipment were built with a gain cell of eight discrete transistors. Later development of these IC’s surpassed all inconveniences of earlier designs, now rendering superior performances. The CompIQ series of compressors use THAT Corporation Blackmer® VCAs which are characterized by an exponential control characteristic (gain varies directly in decibels), extremely wide dynamic range, and low signal distortion. They are particularly neutral in sound, adding little or no coloration to audio signals.

RMS-Level Sensor
Invented by David Blackmer of dbx Inc., the RMS-level detector computes Root Mean Square level of input signals in a logarithmic form, similar to how human ear perceives sound. The envelope decoded by this accurate detector is used to trigger the VCA according to parameters set by the user (Ratio, Knee, SCF, Threshold, Attack, Release, and Gain).

Threshold Range
The threshold’s 50dB of range is designed to accommodate very weak and up to pro-audio level signals. The +4dB pro signal line level is at the top of this range, and consequently at the far clockwise end of the Threshold knob. This gives a huge amount of headroom for the instrument’s generated signals, which ensures the compressor is not distorting with high-level spikes. We didn’t want that, by design. Some other compressors distort a lot, for various reasons, and headroom (or lack of it) is one of them. The CompIQ line of compressors is made to accommodate either lower OR hotter signals, and that is the reason why it can also be used with synths or other line-level devices. We wanted that so that we cover a broad spectrum of usage. As opposed to this kind of design are the compressors which have a very low threshold set hard within the circuit, and they would be controlled through “compression variation” only. This is equivalent to setting our compressors with the lowest threshold, and then vary the compression amount with the Ratio control.

One other fact to point out is the range of a pickup signal, which is in the lower 25% of the pro signal level. This falls as well within the first quarter of the Threshold knob’s rotation range. The compression, or limiting, should only occur on peaks and for that matter, the optimum threshold point for a pickup is also in the lower setting on the Threshold knob, maybe between -30 to -20dBu (by design, -20dBu is also the reference level of the internal circuit). Around 8 or 9 o’clock, you are more than halfway within a pickup signal range. If you are to compress just peaks, you would set the threshold knob at about 9 o’clock or slightly above. At this level, a higher compression ratio makes no sense, unless is the limiting that you’re after. If you want to have a more audible feel of the compression, you would set the threshold knob below 9 o’clock, and the lower you go counterclockwise the smaller compression ratios you should use so that the pickup signal is not squashed too hard. Unless you want to use the squash as an effect! And here comes the “New York compression style” which means compress with a high ratio and low threshold, and mix the compressed wet signal with the dry signal to balance the overall dynamics of the signal.

Side Chain Filter
The Side Chain Filter is a frequency-dependent feature which allows a change in the compression triggering behavior.  The purpose of it is to prevent triggering the compression with the high-amplitude low-frequency content and squish higher frequencies prematurely. This could result in a muffled sound with fewer highs and this is not desirable. To overcome this, we compensate for the low-frequency triggering potential in the side-chain by progressively filtering it downwards from 1KHz, as the graph below shows. This is similar to say that we apply a progressive threshold, where lower frequencies see a higher threshold than the higher frequencies. In fact, the filtered lows in the side-chain no longer trigger the compression of these exact frequencies in the VCA where the program sound is passed through. The lows end up being louder and less compressed at the output of the compressor. This type of compression has a particular sound characteristic perceived as more “full and natural” or “fatter and punchier” to the ear.

Side Chain HPF Options in CompIQ PRO Stella Compressor (-12dB at 90Hz & -12dB at 200Hz)

On CompIQ Stella, CompIQ Mini, and CompIQ Twain the side-chain high-pass filter is switchable for a pre-set amount of cut of the targeted low frequencies.

The Normal option provides a general-purpose type of compression response, while Low and Deep options add a cut of -12dB@90Hz and -12dB@200Hz (-12dB@130Hz for the CompIQ Mini) on top of the Normal side chain curve, making it more suitable for bass-rich or percussive high amplitude input signals.

The SCF processing allows for removing the pumping usually associated with the usage of the “high ratio / low threshold” type of compression. The SCF provides a slightly different compression “feel” when compared with other methods of pumping removals such as raising the threshold, lowering the ratio, using soft-knee compression, blending dry over wet signal, or a combination of all or any of these controls. Of course, the SCF can be combined with all the other controls, giving even greater flexibility in the way the compression is applied to different audio content.

Side Chain Frequency Compensation
Frequency Compensation  refers  to  the shape of the audio spectrum presented to the Side Chain Detector. Due to the nature of audio in general and musical instruments in particular, each musical note has a dominant frequency plus harmonics. The dominant frequency is always higher in amplitude than its harmonics. As musical notes fall lower in the audio spectrum (say notes on the lower strings in a guitar), their dominant frequency has bigger and bigger amplitudes (as opposed to notes on higher strings). That amplitude has the potential to trigger compression too early, and as a result, they may over-compress the harmonics or higher notes. This is usually heard by the human ear. To overcome this, we compensate for the low-frequency triggering potential, by progressively filtering it downwards from 20KHz and then from 1KHz with additional high-pass filters. This type of progressive compensation helps to prevent the “pumping” often encountered in compressors and makes the dynamic processing feel more natural. That is especially true for percussive instruments or for instruments rich in low frequencies, like bass. Side Chain HPF Options in CompIQ PRO Stella Compressor (-12dB at 90Hz & -12dB at 200Hz)

The Normal side-chain roll-off curve above is particular to all our compressors. It provides a general-purpose type of compression response that corresponds to how the human ear perceives the sound. You may notice that even the Normal side-chain roll-off curve is progressive, and is -12dB lower at 2KHz than it is at 20KHz.

On CompIQ Stella and CompIQ Twain the Side Chain Filter has two additional options: Low (-12dB per octave at 90Hz) and Deep (-12dB per octave at 200Hz) on top of the Normal curve. The Deep SCF option on the CompIQ Mini is set to free up -12dB per octave at 130Hz which should serve well both guitar and bass instruments, as well as many others.

When the SCF’s switchable options are combined with Knee selection, variable Ratio and Threshold settings, and the Dry/Wet Mix, they can all fully compensate for the option of a variable side-chain filter control, which would have been difficult to fit into our small enclosures.

Crossover
The CompIQ Twain features a first-order variable 70Hz to 1KHz Linkwitz–Riley type of crossover which splits the input signal into two frequency bands which are processed independently by the two compression engines. The output of the crossover also feeds the Dry Line, so mixing the Dry and Wet signals is possible without phase cancellations, regardless of the crossover’s set point.

Below is a plot showing matched external and internal circuit levels with the crossover set at 1KHz, the output set at the buffer level, and Mix set to 100% Wet. As you can see, the phase of each signal component is almost perfectly aligned in the audio spectrum.

Twain Crossover Phase Shift Plot

It is worth noting that while the input signal’s phase (dotted green) is a straight line, the output signal’s phase (dotted red) is progressively twisted from lows to highs (from almost 0° on the extreme lows up to 400° on the extreme highs). This is normal and is the result of the signal being separated by the crossover’s band filters, and then being re-combined at the output, after passing the compression engines. As a result, when switching from Bypass to Effect, the ear perceives the frequency delays although there is no audible loss of frequency throughout the audio spectrum.

Bellow is a drawing showing the Crossover Knob Frequency Scale and the most appropriate setting for using the Saturation feature.

CompIQ Twain Crossover Frequencies & Best Saturation Range

CompIQ Twain Crossover Frequencies & Best Saturation Range

Tape Saturation Lo & Hi-Cut filters
The Tape Saturation analog circuit is available for the CompIQ Stella and CompIQ Twain compressors. It is designed to act only on the Dry signal. This optionally-saturated signal can then be mixed with the wet, compressed signal, to infuse harmonic distortions and warm-up the audio, without affecting the dynamics of the compressed signal. The headroom of the saturation circuit is pretty high, so you need to dial in some saturation before the effect is audible. For CompIQ Stella, the LPF and HPF can be engaged by removing the two corresponding internal jumpers. For CompIQ Twain, the filters are variable and directly accessible as small trim knobs – the HPF is available for the Lows band and the LPF is available for the High band. On both compressors, the HPF is placed before the Saturation engine and the LPF is placed after the Saturation engine.

Below you can see how the filters affect the frequencies of the Dry line.

The Low & High cut filters should be used only when Tape Saturation is used, otherwise, they will affect the clean dry line, although, that might also be a desirable way of using the Dry/Wet Mix control. The filters were necessary so that they would accommodate different types of audio sources, and respond musically without introducing unwanted fuzziness on the low end (especially for bass), or make it sound brittle (especially on bright guitar pickups).

X-EQ
The X-EQ section of the circuit is placed after the compressor, just before the Mix control, which means it acts on the wet signal only. When mixing the dry unprocessed signal, with the wet, compressed, and processed signal, the effect of the X-EQ is washed out little by little, as you introduce more dry signal.

The X-EQ on Stella has two frequency pivot points so that it will accommodate either bass (pivot at 330Hz, which corresponds to the higher note on the highest note of a 4 or 5 strings bass), or guitar (pivot at 1KHz, which corresponds to the highest note on a 20-fret guitar). In extreme settings (CC or CCW), there is a total difference of 12dB between lows and highs. In the middle position of the X-EQ knob, the frequencies are not affected. The X-EQ section can be bypassed altogether by changing the position of a jumper inside the pedal.

Line-level signals
The maximum input signal level without distortion is in between +5dBu and +10dBu, depending on the compressor model and powering voltage. All compressors have a 50dB threshold range, from -40dB up to +10dB which covers average magnetic pickup level and line-level signals as well. They all can be used on line-level FX Loops or feed the high impedance or line-level inputs on recording interfaces. Having an RMS-level detector, the compression is very accurate, and the LED indication is exact in that regard, as long as the input signal is at/around the calibrated reference level. CompIQ series “0dB reference input level” is internally set at -20dBu (77.5mVrms). The total amount of compression (inf:1 Ratio) depends on the input signal level, usually 20dB for input signals around -20dBu (77.5mVrms) and 36dB for +4dBu (1.23Vrms) input signal levels.

Compressor noise
The rise in noise in compressors usually comes from the make-up gain amplification. This means that the more you compress, the more make-up gain is needed, and more amplification noise is introduced to the signal (and that may be avoidable when using compression in a smart way). That noise propagates further in your setup and could be amplified by the following pedals which add their amplification noise as well, including the amp used at the end of the chain. Similarly, any amplification device placed in front of the compressor may add amplification noise and that is picked up and amplified by any make-up gain circuit further down the line.

It is important to note that if your compression setting needs a lot of make-up gain then the amplification noise will be way higher and audible during the absence of the working signal (music pause). This is because the signal to noise ratio is very low during such pauses (actually, the noise is higher than zero signal, which means you are in negative SNR) when compared with the signal to noise ratio during compression. You should not expect to dial in +20dB of gain and hear no noise. However, if you compress the signal -20dB then recover it with +20dB of gain then the amplification noise is only hardly audible, yet obviously there. You cannot avoid this. And, if you want to understand how hugely loud 20dB of gain gets, set the compression to 1:1, dial in the make-up gain to the maximum and play. In fact, if you need the entire available make-up gain you are in hard-limiting territory and no longer compressing.

To correctly compare compressors noise, they must be set for the same exact amount of threshold, ratio, and make-up gain, and be fed the same reference signal. Some manufacturers limit the Ratio of their compressors to 7:1 or as low as 3:1 and those indeed make for “very silent compressors” because they don’t need as much re-amplification. Of course in this regard, the “silence” characteristic has a subjective meaning if it’s not a misleading statement.

Particularly with the CompIQ Twain, it is easy to add more noise than necessary in the Stacked Mode, which puts the compression engines in series, like you would stack two pedals. We do explain more about this in the Twain Settings Examples, and the trick to controlling amplification noise in this mode is to use the last (highs) engine compression and make-up gain more than what you use in the first (lows) engine. You would try not to compress too much in the first engine and keep the make-up gain low, then go furthermore in the second engine and use its make-up gain as a master gain. Another trick is to pass some of the frequencies to compress to the second engine by means of, raising the lows threshold, using the Low or Deep side-chain filter, and using the soft knee to mitigate either noise or compression feel. You may combine these controls in both engines to find the sweet spot for your application.

The dual-band processing is usually more tricky and is more of a specialty type of compression, where it is easier to set it “wrong”, although there is no wrong in setting it in any way. It is just that what works for full-band compression cannot be applied one-to-one to dual-band compression.

Besides that, the crossover used in dual-band compression is an “always-on” circuit that has many passive components which are needed in the filters section, and all the resistors that compose these circuits inherently add what is called “thermal noise”. And that, of course, is also getting amplified with the make-up gain. This is valid for any dual-band compressor.

Here is a working strategy. Try to understand how the compression controls (threshold, ratio, knee, timing, blend, side chain filter, gain) affect compression in general and ask yourself what you are trying to achieve. Combine these parameters to set up compression in such a way that the make-up gain can be set lower.

Worth knowing:

  • at higher input signal levels, the makeup gain-related noise will be lower, because you deal with a bigger signal in the first place;
  • if you set a higher threshold, hard knee, and inf:1 ratio and you affect only the peak of the signals – as this limiting setup makes sense to be used – the noise will be inaudible.
  • for weak magnetic pickup signals, at the lowest set threshold and with ratios around 4:1 (which is a fair amount of compression), the CompIQ make-up gain will introduce noise similarly to studio-grade equipment.
  • on top of Threshold, you have the MIX control which helps reducing noise by blending in the dry signal;
  • using soft knee also contributes to reducing the need for make-up gain, so implicitly it reduces potential noise.

Power sources are also a proven source of adding noise to electronics. Switching power supplies will almost always add hiss. We recommend using only good quality, well filtered, and regulated power sources. The pedals in general do not have enough space to fit large capacitors and additional necessary electronics for good power conditioning. And, pedals are not supposed to filter power sources anyway.

Switching noise
Pops or static noise may occur when switching the following settings with the pedal engaged:

  • Knee
  • Timing
  • Side Chain Filter
  • EQ Pivot
  • Dual-Band/Stacked
  • Power On/Off

Gain Reduction Meter
The gain reduction meter is available for all compressors in the CompIQ line. They measure how much compression is applied to the input signal. The indication is in dB. Depending on the product, the metering ladder is differently configured. Keep in mind that due to the limited number of LEDs in the meter, the compression is “invisible” in between the LEDs. Ideally, a full meter scale would have a minimum of 20 LEDs, one for each dB of reduction.

The metering in each product was designed and calibrated to reference the comparators to 9-12VDC for an accurate gain reduction indication. However, the CompIQ Twain can also be powered at 18VDC. At 18VDC, several thresholds that are calibrated for metering are a bit shifted, and as a result, the metering shows around -3dB less in the meter. Usually, a proper powering of an electronic circuit is with a fixed voltage +\- some tolerance. But 80-100% voltage up shifting, also shifts some calibrations within the blocks of circuits inside. While the audible side of the change is for the better and likable, the precision of the metering reacts to this shifting and introduces a variation.

There is a possibility that the meter LEDs remain “locked” lit in some conditions outside the normal usage of the pedal. For example, this may happen when powering the pedal at a higher voltage and switching the Knee in some particular circumstances such as when the knobs are set for compression but no input signal is present or input cable’s jack is not inserted in the pedal.

The gain reduction meter needs an input signal that varies up and down the thresholds set for each LED, and while a raising signal lits them, they must also be turned off by a decaying signal. The electric spike introduced by switching the knee (which is a change of the operation mode of a portion of a circuit while also setting the rest of the controls for compression) varies very shortly and it does trigger the LEDs although no signal on the input of the metering circuit is present so that the LED’s are reset. Nothing is broken and nothing breaks – is just a condition you put the circuits in, but that condition is different from the intended usage of the pedal.

To prevent that, switch the knee when you don’t play but you must have the input and output plugs inserted in the pedal. To switch off the LEDs that remain lit, power off the pedal and then on again OR, play your instrument with a signal higher than the LEDs on the display that remain lit. This way the circuit sees the decaying signal and the comparators are reset. Alternately, power the pedal with 9-12VDC instead of 18VDC.

Powering voltage range for the CompIQ line of compressors
Although all CompIQ line of pedals can be powered in the 9-18VDC range, we conservatively designed and calibrated some portion of the circuits (like the gain reduction meter) to be run in the 9-12VDC range. The headroom is more than enough at these voltages, and we can also protect the circuits in the long run from accidental failures of power supplies.

Please be sure you only use good quality and regulated power supplies because the 18VDC is the absolute maximum for some of the ICs inside. And although they might still support some minor voltage spikes, say at up to 10% you might still be safe, if the power supply fails and supply higher 20ish Volts into the pedal, then those active components might fail.

It is advisable to have the pedals pre-connected to the power supply prior to powering the power supply from the AC outlet. In other words, only power the pedalboard at once by switching ON the AC switch on the power supply, or put the plug into the AC wall wart if no AC power switch is available. This prevents the possibility of a short burst of voltage when a load is connected to a powered DC port. If you power the entire pedalboard at once on the AC side (power switch or wall wart plugging) then the distributed load on the DC side of the supply is already connected and the draw of current might be better controlled and voltages better kept on regulation at each available power output.

The circuits in our pedals have other protections as well, like reverse polarity, yet there is a limit that these protections can handle.

Demos, reviews & comments


Blog post: The 101 of the CompIQ line of compressors

Settings Examples

Before you start

The CompIQ Stella is a full-featured compressor in pedal format which allows complex processing while preserving the dynamics of your playing. A good understanding of compression is normally required to optimally set it up for live performance or studio recording.

We advise testing the CompIQ Stella with an instrument amplifier instead of using headphones. Start by playing with it alone then integrate your settings along with your other pedals.

Here is the Stella Manual for your reference. For more in-depth technical info on our VCA line of compressors please take a look at the CompIQ 101 section. If you have particular questions regarding how the Stella works, or you would like to share your feedback please contact us.

Stella sound demos on bass

Each demo has an associated image with pedal’s knobs & switches position used when recorded. A higher resolution image is displayed when loading the track on Soundcloud — along with details regarding the instrument, strings used for that phrase, and playing technique. Start by playing any track in the playlist below and click View Track to load it on Soundcloud for details.

The audio phrase is played twice in each track. First, the dry sound with pedal in bypass, followed by the take with pedal engaged.

Many thanks to jazz artist Jean-François Untrau (France) who recorded these demonstrations.

Stella + DITOS sound demos on guitar

Back to Product Page

Blog post: CompIQ Stella Settings Examples

Video Demo / Guitar

CompIQ Stella Compressor on guitar

Sound On Sound Magazine UK - Review - July 2020 IssueIn short, it’s what I’ve always wanted of a compressor pedal. The Stella can sound wonderfully transparent, or full of character, and there’s oodles of control at your fingertips. Bass players should absolutely love this thing (though I suspect they may be even more enamored with the company’s new split-band compressor).

Vintage Guitar Magazine USA - VG Approved Gear Review - May 2020 IssueThe CompIQ Stella has a ridiculous amount of power for a small stompbox. Better still, it's a transparent compression that only colors the tone as much as you allow it, unlike many lower-end boxes that simply squash tone and volume. That's the sign of a good unit - delivering compression power, clarity, and flexibility to control exactly what you want to hear from a guitar.

Guitar.com - Becos Effects’ CompIQ Pro Stella Compressor features rack-style controls on a stomperThis pedal is designed to provide an array of features – with rack unit-levels of tweakability – in a pedalboard-friendly format. A highlight of the CompIQ Pro Stella Compressor is its analog tape saturation circuit.

Music Radar - Guitar and bass stompbox delivers dizzying array of featuresCompIQ PRO Stella for guitar and bass delivers dizzying array of features. There are a staggering number of parameters onboard, which promise the versatility of a rack unit in a compact stompbox.

Extensive review of CompIQ PRO Stella Compressor on TalkBass.com ForumThis is a highly versatile and pedal board friendly compressor. I'm not aware of anything on the market that packs this much punch in terms of functionality. In many ways, it has raised the bar for compressor pedals. The words "Pro Compressor" on the face of the compressor is appropriate. There is a whole lot of versatility in an amazingly small package.

Guitar World - Knob-heavy pedal offers compression, limiting, tape saturation and more.Knob-heavy pedal offers compression, limiting, tape saturation and more.



COMPARE COMPRESSORS

The comparison table is best viewed on large screens, in landscape mode, preferably on desktop.

Circuit Design
Dynamic Processing
Analog Engines®
Control Element
Side-Chain Detection
Side-Chain Filter
Side-Chain Frequency Compensation
Adjustable Input Level
Input Clipping LED
Balanced Output
Crossover
Compression Ratio
Threshold
Dynamic Auto Timing
Attack Time
Release Time
Make-up Gain
Compression Knee
EQ
EQ Bypass
Dry/Wet Mix
Saturation
Saturation Filters
Compression Display
9V Battery Operation
DC Power Range
Current Consumption
More Info
Compressor / Limiter
Dual Band / Stacking
2
Blackmer® VCA
True RMS-Level Sensor
Normal / Low / Deep
lows only
YES
-9dB to +6dB
> +6dBu signal levels
-
Linkwitz–Riley
70Hz to 1KHz
1:1 to inf:1
both bands
-40dBu to +10dBu
both bands
Auto Fast / Slower
both bands
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
both bands
Hard / Soft
both bands
Through Make-up Gains on Wet line (boost/cut)
-
YES
On Dry Line
adjustable
Lo / Hi Cut filters and Level controls
6-LED
both bands
-
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 69mAh @ 9VDC
< 110mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
True RMS-Level Sensor
Normal / Low / Deep
YES
-
-
Transformer Balanced / Floating
with optional DITOS DI board
-
1:1 to inf:1
-40dBu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
Manual: 0.12 ms/dB to 12 ms/dB
F / S: 70ms / 100‐220ms
Manual: 1.2 ms/dB to 120 ms/dB
-6dB to +20dB
Hard / Soft
X-EQ +/-6dB with Low / Deep frequency pivots
Effect Hardwired ON
YES
On Dry Line
adjustable
Lo / Hi cut filters
(inside jumpers)
8-LED
YES
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 35mAh @ 9VDC
< 63mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
True RMS-Level Sensor
Normal / Deep
YES
-
-
-
-
1:1 to inf:1
-40dbu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
Hard / Soft
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 15mAh @ 9VDC
< 23mAh @ 12VDC
Compressor
Single Channel
1
Blackmer® VCA
True RMS-Level Sensor
Normal
YES
-
-
-
-
1:1 to inf:1
Lo: -40dBu / Hi: -30dBu
Auto Slow
12ms
220ms
-6dB to +20dB
Hard
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 15mAh @ 9VDC
< 23mAh @ 12VDC

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