Wednesday, 7 September 2016

Palenque - Mexico

Situated in one of the northern states of Mexico (Chiapas), Palenqes famous for its Mayan ruins in the jungle.




Lots of climbing in the tropical heat.


There are 100s of ruins spread over 15 sq Kms.


A limestone relief from the "Patio de los Cautivos".... war captives.
A inscription on the stairway in House C mentions the birth of Pakal II (603AD) and a war that he waged against the Pomona.












An ancient Mayan football field.
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Thursday, 1 September 2016

sidechain compression - eurorack modular

 Sidechain compressors.
 
Compressors are essentially devices used to make loud sounds softer.
They enable a producer to boost the level of a track, thus narrowing the dynamic range.
This type of compression is evenly applied to the tack
 
Side Chaining is a more active type of compression.
It's sometimes referred to as "ducking".

It is a type of compression where the volume level of one instrument is controlled by the volume level of another instrument
That is, the compressor is only triggered when certain sounds appear.
This is the pumping effect  you often hear in electronic dance music.
Here, the compression level on a bass track is controlled by the output volume of a kick or snare drum.
The Bass line volume drops every time the kick is heard.
Another example of its use is when a song suddenly drops in volume when a radio announcer speaks.
 
 Daft Punk - Indo Silver Club (Official Audio)
 
Thus for side chaining, we need an external signal to act as the trigger.
 
To build your own side chain compressor using a eurorack system
we need a 
1. drum source 
2. Baseline
3. VCA
4. EG with an inverted output
 
The EG could be replaced with a Envelope follower & an inverter.
 
 
In this case, the VCAs gain needs to be turned up.
The baseline is passed through the "open" VCA.
Everytime the kick sounds, it triggers the envelope generator.
The inverted CV lowers the volume of the VCA 
 

These two videos are really good to watch.
  
 
They use the MATHs module
 
 
 
This second video is esp good
 
This is my usual setup.
 

 
I'm using the the Make Noise Function instead of a Maths.
I like to set Rise to full anti clockwise & Fall to about 11 0'Clock to get a ducking effect. 
A fast attack & a slower decay. 
Play around with these settings to adjust the amt of ducking.
The bubblesound VCA is set to expo and CV in to around 3 0'Clock

The Doepfer A-171-2 VC slew Processor works very much like Maths and Function
 

 
It's mostly a licensed copy of Ken Stone's vcs (voltage controlled slope)
 which is in turn based on the Serge vcs.
 
The VCS is a really useful module. Quite versitile.
In this instance it's being use as a voltage controlled envelope generator with an inverted output.
The top and bottom pot are the most important parameters to adjust.
 

Wednesday, 31 August 2016

Malekko - Wiard - Xmix


The  Malekko Wiard XMIX is a mixing/crossfading utility module.
I understand it's different from the 300 series Mixolator which used a  CA3280 transconductance amplifier.

 The XMIX is 8hp wide, 25mm deep, and consumes approximately 45mA power.

There are two inputs (X and Y). 

The Y input can be inverted via a switch.
Z controls the balance of X Vs. Y. 
Z has a CV input, along with an attenuator for CV amount. 
Positive and negative outputs are provided, as well as an Expand input which provides a unity input to chain the output of other modules (such as another XMIX).


Some uses for the XMIX (Manufacturer's manual):
– A 2 > 1 Mixer
– CV crossfading
– A signal inverter
– Audio rate amplitude/crossfading modulation
– With a single input, you can use the XMIX as a linear VCA
– Input different waveforms to create new wave shapes
– The X input normals into the Y input when nothing is plugged into Y. Invert the Y input with the switch, and crossfade the X signal VS the inverted version of itself
 
 
 
 
 
 
 
 
------------------------------------------------------------
 
There is a three pin connector on the back of the PCB that goes hot-ground-cold.

Connect this to an XLR or TRS and you have a low impedance balanced send.

--------------------------------------

mAKING  a  ADSR Envelope.
You will need two Envelators. 
 

1. Set 1st to AD mode, and 2nd to AR mode.
2. send a trigger to the 1st Envelator.
3. send a gate to the second envelator .
4. take outputs of each Envelator into the inputs of the xMix
    AD Envelator plus output to X input of XMIX (X control set to max)
    AR Envelator plus output to Y input of XMIX (set Y polarity to plus and Y control to max).
5. The ADSR envelope is available at the XMIX plus output 
6.  The XMIX "Z" control acts like a "Sustain" control.  
     The "ZMOD" input can be used as voltage controlled sustain level input.   
 
Take the output of the xMix and input into a VCA 

The Wiard Xmix can be used as a mixer & as a VCA.
I find there is a little bit of audio bleed when I use the Xmix as a VCA.
I prefer to use a dedicated VCA for this task.
 
------------
Balanced (ring) modulation. 
  • 1. Make sure the X & Y knobs are at full.
    2. Connect your carrier sine wave (or whatever) to the X input.
    3. The Y input is normalled to the X input so the carrier is going to X + Y.
    4. Switch the Y input polarity to negative (minus).
    5. Monitor the plus output.
    6. Adjust the Z control to get the best carrier null.
    7. Now run anything into the Z control input (modulator), Z Control is the volume for the modulation input.
 Thanks to "shady smiles" for the ring mod patch.
-----------------------------------
Unbalanced modulation (VCA)
 

 X in = Audio in
+ out = Audio out.
Zero both Y & Z pots.
Z control pot is set to Max
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Links:

Saturday, 27 August 2016

3TrinsRGB+1c build pics & initial tests

3TrinsRGB+1c is an analog audio/video synthesizer

 This build took about 3- 4 hrs. It's not difficult but it's not for beginners either.
Some closeups from various angles. Hopefully this will help future builders.




The pot in the foreground is the only 20K one . ... has the gold top.


There is a transistor missing in the above pic -- to the left of the 10uf cap.






This is the 2016 version
..
 Note the two resistors below "VidIn"
 In the pic below, the 10R is missing.
First tests:
The middle white LED didn't work, so had to be replaced... just like in GGs video.
I don't think the LEDs effect the operation of the buttons.






Nice, the video in works perfectly.
The manual is here:
http://gieskes.nl/instruments/files/3TrinsRGB1/3TrinsRGB1c-manualV1.pdf

Watch this video at least twice before you build anything.
Essential viewing.
https://www.youtube.com/watch?v=QqKOfuUpSV8

And GGs website is here:
http://gieskes.nl/instruments/?file=3TrinsRGB1
Assembly instructions:
https://www.flickr.com/photos/62323010@N00/26454192491/

LZX basic patches

 Some very basic patching with an LZX modular. Using two waveform generators (right), a doepfer A110 VCO and a color video encoder.

Adding in a sensory translator and two logic modules: video divisions & video flip flops


The system is slowly coming together.

Links:
1. Advanced patches

Sunday, 21 August 2016

While Loops - Arduino

 While loops

Allows more flexibility than a for loop.
A while loop will loop continuously, and infinitely, until the expression 
inside the parenthesis, () becomes false. 
 

Syntax

while (condition) {
  // statement(s)
}
 
 -----------------------------------------------------------------

Example Code

var = 0;
while (var < 200) {
  // do something repetitive 200 times
  var++;
}
 -----------------------------------------------------------------------
 

 
//This code will print the numbers 1 to 10
//print a space
//then loop

int j; // counter
int delayTime=100;

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  j=1;
  while (j<=10){
    Serial.println(j);
    delay(delayTime);
    j=j+1;
  }
  Serial.println(); // prints a gap
    
}
 
 ----------------------------------------------------
 example 2
while the voltage at the pot is less than 1023 (5V)
the LED is off.
Any voltage above this turns the LED on.
 


int j; // counter
int potVal; // 0 to 1023(5V).. value of pot
int delayTime=100;
int potPin=A0;
int redPin=7;


void setup()
{
  Serial.begin(9600);
  pinMode(potPin,INPUT);
  pinMode(redPin,OUTPUT);
 
}

void loop()
{
  potVal=analogRead(potPin);
  Serial.println(potVal);
  delay(delayTime);
 
  while (potVal>1000) {
    digitalWrite(redPin,HIGH);
    potVal=analogRead(potPin);
    Serial.println(potVal);
    delay(delayTime);
    
    
    
  }
 digitalWrite(redPin,LOW);
    
}

 
 Links
 
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Wednesday, 17 August 2016

Compressors for Audio

 This is an attempt to demystify audio compressors.
They are useful both in the music studio and when performing live.
It's all about reducing & smoothing the audio peaks and troughs.

I have a few different types, ranging from small modules to rack units.
They all however have similar controls.
There are also quite a few eurorack compressors.
My favourites are the WMD MSCL and the L-1micro compressor 


You can actually build a compressor with a envelope follower, a an inverter and a VCA. A modular compressor is essentially a voltage controlled envelope follower tied to a VCA.
 
+ Modular Compressor -using eurorack modules
 
 
The MSCL is unusual in that it doesn't have the usual controls.It's inspired by the classic 
DBX "over easy"style compressor . The threshold, gain & output are all controlled with one
knob and two switches. 
 
This is an excellent stereo compressor for a small modular system. It packs in a lot for just 4HP
 
The Limit Switch limits the make-up gain allowing the MSCL to act like a peak limiter. 
The Threshold Switch helps compress signals of different amplitudes. Both modular & line level.


Both switches have 3 settings:left (off), middle(half on),right (full on).
The side chain input helps create your ducking sounds.
 
To turn on the compressor, I like to turn the LIMIT to the left & 
THLD (Threshold) slide switch to the middle to start with.
 
The Limit is your final volume. 
The Threshold is the volume the audio has to reach before compression begins.
 
I usually end up with both switches in the middle or maybe one of them 
to the right (usually the threshold).
Often I'm mixing Line Level audio with Modular audio and these have 
huge volume differences.
 
The lower toggle switch needs to be in the centre position.
I usually set the COMP knob to around 75% and GAIN to 50%
As you turn up the COMP knob you will see the LED change from red to green.
Red is your gain reduction. Green is gain addition.
(The GAIN knob is your Makeup... so use it at the end of the audio chain). 

Play around with the envelope. Turning up the attack will let the
beginning of your kick drum through. These envelop knobs are a great
performance feature

The bottom 3 throw toggle switch has side chain, in, out.
IN = wet compressed signal
OUT = dry uncompressed signal.
Switching between these two is a great way to compare.
As WMD say in their video .. "don't be afraid to use your ears"
Just listen to how each sounds and make your adjustments accordingly.






Threshold

 This sets the volume the audio has to reach before compression begins.
It acts like a gate. 
Adjusting this control sets the level at which the gate will open and allow the signal 
at the input to pass through to the output.

Ratio

This is the amount the audio is reduced (over the threshold).
It's as the name suggests a ratio.

When an input signal is above the THRESHOLD reference level, the setting of this control determines the number of decibels (dB) by which the input signal must change in level to produce a 1dB increase in the signal level at the output
 
Common ratios you will see are:
1:1
1.3:1
2:1
3:1
4:1
Infinity :1
---------------
 
1:1 is no compression
Infinity :1 , Here the compressor acts as a limiter as audio will never exceed the threshold.
 3:1 here the audio above the threshold is compressed a third.
So if the sound peaks 15dB over the threshold, it will be attenuated to 5dB over the threshold.
 
I tend to set the ratio between 3:1 to 10:1
Above this, it tends to clip the audio.
 

Attack

The ATTACK control is an envelope. Just like a ADSR. It sets the amount of time it takes the module to begin compressing a signal once the threshold is breached. The ATTACK range is from FAST (for a tighter and more noticeable compression effect) to SLOW (for more delayed, gradual compression). 
 

Release

The RELEASE control sets how fast the compression circuit returns the input to its original level. 
Again this is very similar to the ADSR envelopes you are used to with modular synths. The RELEASE rate is from FAST (where the compression slope is steep) to SLOW (for very smooth, gradual compression). 
 
There is no absolute right way to set the ATTACK and RELEASE controls.


MakeUp / Output Gain

The OUT-PUT GAIN control  is also known as MAKE-UP.
It does not interact with the threshold of compression.
Use it to compensate or Makeup for any drops in the final volume which may have occurred during compression 
 

Knee

While discussing the MSCL compressor above, I mentioned the DBX "over easy" style.
This is where Hard vs Soft knees curves come into the discussion. 
"Over easy" seems to be dbx's way to describe a "soft knee".
A soft knee will yield a generally "softer" more subtle compression effect. 
 

It is, in effect, a variable threshold since there is no distinct point at which processing begins.
The compression ratio will start climbing gradually before you approach the threshold as opposed to suddenly "kicking in" all at once at the threshold. 
 
Some compressors have an adjustable knee. I haven't seen many of these in the eurorack format
 

Multi-Band Compression.

There aren't many of these in Eurorack.
Here, the sound from your modulars is split into multiple frequency bands using modules like
EQs. Three bands is the most common number. 
Each frequency band is then compressed separately after which the audio streams are
mixed back together.


I particularly like the Endorphin.es golden master.
It's a 3 band equaliser with a compressor for each band.
Just 6HP
What it lacks in compressor controls it makes up for in size and ease of use.
Sounds great too.


















2HP also make a compressor.
It might be fun to have a few of these chained to an EQ to make a multi-band compressor  with lots of control

 

Peak vs. RMS

Peak value is the highest voltage that the waveform will ever reach, like the peak is the highest point on a mountain. The RMS (Root-Mean-Square) value is the effective value of the total waveform.
When it comes to compressors, these two settings refer to response times.
Peak compression is great for things like drums.The compressor's changes occur much quicker.
RMS changes are slower and good for slower sounds like strings or pads. 
 
 

Sidechain

This effect was first developed in radio studios. The background audio could
be dropped automatically when the announcer spoke. 
Thus, the volume level on one instrument is controlled by the volume 
level of another instrument. A common example would be making the 
compression level on a bass controlled by the output volume of the 
kick drum.  This is called Ducking.
 
I really like the endorphin.es Cockpit. 
Though it's not marketed as a compressor, it's ducking is great for getting
that pumping sound. 
It's really a mixer with a VCA.  
 
 
 
 
 
 
 
 
 
 
 
 

Feedback (feed forward) compression.

Here, the input signal is split into two. One goes into the compressor itself.
The other goes into the sidechain. The sidechain is then fed by the output of the compressor.
This type of compressor was made famous by the Universal Audio 1176.
 


LIMITING

This is where you set the max volume your signal will reach.
It provides overload protection.  
 
 
The Audio Damage ADM10 Kompressor is DSP based.
Just 6HP. Nice 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Other eurorack compressor modules
+ Autodyne - SSF
+  Dynamo - Bastl
+ Mutant Hot Glue - Hexinverter
+ Mutable Instruments Streams 
 
An example of a compressor in a pedal format.

Links