70Hz to 1KHz
Manual: 0.12 ms/dB to 12 ms/dB
Manual: 1.2 ms/dB to 120 ms/dB
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, this 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 limiting you’re after. If you want to have a more audible feel of the compression, you would set the threshold knob bellow 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.
Worth mentioning is that all CompIQ compressors have a hard-set signal level protection which is 1.2Vp-p or just around the pro signal level. For higher input levels than that, the circuit gets into distortion, which is generated by the protection and not within the compression electronics. Such protection is needed to avoid damages within the electronics due to input spikes or accidental DC leakage. Anyway, guitars and basses will not get to that top-level easily, unless they are put after a device that would be cranked up.
In CompIQ Stella, CompIQ Mini, and CompIQ Twain the SCF is switchable for a pre-set amount of low-cut of the triggering frequencies. The Normal option provides a general-purpose type of compression response which is frequency-compensated to resemble the human ear perception of sound, 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 suitable for bass instruments.
The Normal side-chain rolloff curve above is particular to all our compressors, providing a general-purpose type of compression response that corresponds to how the human ear perceives the sound. In CompIQ Stella and CompIQ Twain the Side Chain Filter has two additional options: Low (-12dB@90Hz) and Deep (-12dB@200Hz) on top of the Normal curve. The Deep SCF is set to -12dB@130Hz for the CompIQ Mini.
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.
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.
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).
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 in 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.
- 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.
- Side Chain Filter
- EQ Pivot
- Power On/Off
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 goes up and down against the thresholds on each LED in the meter and while they are lit by a raising signal, they must also be switched 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.
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 spikes more or fails altogether and bursts a constant 20ish Volts into the pedal, then those active components might fail.
The circuits have other protections as well, like reverse polarity, yet there is a limit these protections can handle. That is valid for all our compressors.
- Sound on Sound Magazine – CompIQ STELLA – Review
- Vintage Guitar Magazine – CompIQ STELLA – Review
- Gitarre und Bass Magazine – CompIQ TWAIN & STELLA – Review
- Guitar Magazine – CompIQ STELLA – Best Compressors in 2020
- Guitar Magazine – CompIQ TWAIN – Review
- Guitar Magazine – CompIQ STELLA – Review
- Premier Guitar Magazine – CompIQ TWAIN – Review & Sound Samples
- Premier Guitar Magazine – CompIQ TWAIN – Gear Radar
- Premier Guitar Magazine – CompIQ STELLA – Pedal Showcase
- Premier Guitar Magazine – CompIQ MINI – Quick Hit Review
- Guitar Pedal X – CompIQ Compressors Line-Up
- Compressor Pedal Reviews – CompIQ TWAIN – Review
- Compressor Pedal Reviews – CompIQ STELLA – Review
- Compressor Pedal Reviews – CompIQ MINI – Review
- Compressor Pedal Reviews – CompIQ MINI ONE – Review
- Onlybass Forum – CompIQ STELLA – Users Review (French language)
- Onlybass Forum – CompIQ STELLA – Review with sound samples (French language)
- Onlybass Forum – CompIQ MINI & STELLA – Reviews & Comments (French language)
- Talkbass Forum – CompIQ MINI – Reviews & Comments
- Talkbass Forum – CompIQ MINI ONE – Reviews & Comments
- Talkbass Forum – CompIQ STELLA – Reviews & Comments
- Basschat Forum – CompIQ STELLA – Review
- Basschat Forum – CompIQ STELLA – Reviews & Comments
- YouTube – Reviews and Demos