September 2019

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 DC Power Plug Barrel Current Consumption More InfoAdd to Cart TWAINCompressor / Limiter Dual Band / Stacking 2 Blackmer® VCA True RMS-Level Sensor Normal / Low / Deeplows only YES -9dB to +6dB > +6dBu signal levels - Linkwitz–Riley70Hz to 1KHz 1:1 to inf:1both bands -40dBu to +10dBuboth bands Auto Fast / Slowerboth bands F / S: 5‐7ms / 10-15ms F / S: 70ms / 100‐220ms -6dB to +20dBboth bands Hard / Softboth bands Through Make-up Gains on Wet line (boost/cut) - YES On Dry Lineadjustable Lo / Hi Cut filters and Level controls 6-LEDboth bands - 9-18VDC center negative Ø 5.1/2.1mm, 12mm long < 69mAh @ 9VDC< 110mAh @ 18VDC CompIQ 101Add to Cart STELLACompressor / Limiter Single Channel 1 Blackmer® VCA True RMS-Level Sensor Normal / Low / Deep YES - - Transformer Balanced / Unbalanced (Floating)with optional DITOS DI board - 1:1 to inf:1 -40dBu to +10dBu Auto Fast / Slower F / S: 5‐7ms / 10-15msManual: 0.12 ms/dB to 12 ms/dB F / S: 70ms / 100‐220msManual: 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 Lineadjustable Lo / Hi cut filters(inside jumpers) 8-LED YES 9-18VDC center negative Ø 5.1/2.1mm, 12mm long < 35mAh @ 9VDC< 63mAh @ 18VDC CompIQ 101BUY NOW MINICompressor / 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 CompIQ 101BUY NOW ONECompressor 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 CompIQ 101BUY NOWMINI Pro vs. other minionsDo 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® VCAFirst 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 SensorInvented 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 RangeThe 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 varying 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 FilterThe 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. 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 CompensationFrequency 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. 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...

The 101 of the CompIQ Line of Compressors