Version 1 3rd Party Modules


The percentage after the name shows what percent of a single Sharc  these modules use up. (Taken from Paul van der Valk's  modular usage charts.)




SpaceF Text  Module (0%)

This indispensable  module can be used to label different sections of your Modular patch. You can see it in action here and download it here. Mehdi has also made a text modular for version 2 which you can download from SpaceF.





Orbitone Envelope Follower (1.8%)

An envelope follower tracks an incoming audio signal and derives an envelope signal from it. The response time of the follower and output depth are adjustable.



(The Obsidian modules were originally produced by Guy Eastwood's Obsidian UK. Obsidian no longer operates, and no contact address for Guy is currently known.) 

Many thanks to Guy for his patient explanation of what some of these modules actually do!

(Although these modules are designed for use with the Modular I, they will still work in Modular versions 2 & III.)


Obsidian 24db MultiMode Filter (16.8%)

4 Pole MultiMode filter with Modulation Inputs for Filter Cut Off and Resonance. Parallel outputs for High, Low & Band Pass filters. 
Obsidian DC+/- (1.9%)

Adds/Subtracts a DC offset to the signal - ie, raises or lowers the signal above/below the 'zero crossing' line' Amount of offset is adjustable and modifiable.
Obsidian DL32K (3.6%)

 Short delay line (up to 32000 samples - or  0.7 of your earth-seconds at a sample rate of 44khz). Delay length is modulatable.

Obsidian DL800 (4.7%)

Also known as a combing delay, this is an extremely short delay line which can be used to produce a comb filter effect by  introducing a very slight offset between the original signal and the delay output. It has a mod input to modify the length of the delay.

See this issue of Sound on Sounds Synth Secrets for a more detailed explanation of  phase offsets, delays and comb filters.

Obsidian Envelope Follower (1.9%)
An envelope follower produces an envelope signal dynamically according to the level of an incoming  signal. Attack adjusts the response time, Release the time for the envelope to return to zero and hold the time between the two, just like an  AHD envelope.
Obsidian Feedback (0.9%)
Allows the connection of (for example) the output of a delay to it's input. Without this module, an error will occur, with it, you are in dubby heaven. Feeding the output of a delay back on itself is one of the tricks of trade of the dub producer. Can produce some very interesting effects with delays, flangers, choruses, etc.
Obsidian Fuzzer (2.4%)
A simple distortion effect with seperate controls for Drive, Sustain, Distortion and Output gain.
Obsidian Integrator (1.2%)
The Integrator outputs the change between successive samples. The slider works as an input gain control - at higher levels, the Integrator produces a harsh but sometimes usable brutal distortion. 
Obsidian Invertor (0.4%)
Outputs the inverse of the signal. If it receives +5v, it'll output -5v, and so on. (I know we're not really dealing with volts here, but you get the idea!)
Obsidian Multiplier (0.5%)
Outputs the Multiplication of the two incoming signals. Similar to a Ring Modulator, but a Ring Modulator outputs the Sum of and the Difference between the two signals.
Obsidian Sample & Hold (1.8%)
Analyses the amplitude of the signal coming in at a particular moment, and outputs this value until the next trigger is received. The level of the incoming signal can be adjusted as can the Threshold (Trigpoint) over which a new sample will be taken. Trigger Input can be an audio signal, LFO, gate, etc. One use for a Sample and Hold module is as a means of producing random output. For example, if the S&H module is fed noise, then a new random sample will be output at each successive trigger event.
Obsidian Shaper (1.6%)
Shapes the signal coming in by decreasing the gain (by the - ratio factor) of any signal coming in over the threshold set by the - break control and increasing (by the + ratio ratio) any signal coming in under the + break control.   In this respect it works somewhat like a hard knee compressor, reducing the dynamic range of the signal.
 Obsidian Slew Limiter (5%)

A slew limiter controls the rate at which a device is able to change its output. Lets say that a device has a theoretical rate of change of 65,000 volts per millisecond, and slew limiter will limit this to a user defined amount, such as 50,000 volts per millisecond. This will greatly affect the harmonic content of the resulting signal.


One example of this is that square waves when 'limited' will tend towards triangle waves as the device's output endeavors to catch up with the 'expected' output level and so forth. 

The Slew Limiter acts like a sort of low-pass filter but has many other applications with lo-freq signals like envelope shaping and attack curve limiting. It can be thought of like the attack/decay element of a compressor/adsr


The Obsidian slew limiter has +ve and -ve slew rates allowing for asymmetric deformation of the input wave which carries further benefits in the harmonic distortion of the output. A link button will defeat the asymmetry, linking the +ve controller to affect both +ve and -ve portions of the wave. Uses for slew limiters include attack smoothing in compressors, vocoder envelope-follower smoothing where tight tracking values are used, etc etc. Also it should have some interesting effects on plain audio, too.. especially in asymmetric mode.

Obsidian Summer (0.5%)
Sums the signals coming in at Inputs A + B.


There is one more module in the Obsidian module pack, the Difference module. Unfortunately it's a bit knackered since the release of 2.04a. Guy knows about this and will fix it if he can. The module outputs the difference between two signals. You can achieve the same effect by putting the signals into a summer but invert one input first.

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