Karplus-Strong guitar string synthesis with Pure Data

Presented here is a Pure Data patch that generates, without samples, a fairly decent acoustic guitar sound. This uses the Karplus Strong algorithm, in which an initial noise burst is fed into a tuned delay line (a delay line whose length equals the period of the desired frequency). The string's vibration is damped by a lowpass filter in the delay's feedback line.

The synth is built from six instances of this karpluck~ abstraction, one instance representing a single string. Each is synthesized in complete isolation: in this simple model there is no sympathetic resonance crossover between the strings.

Patch articulation comes from a simple strummer sub-patch. This generates a random sequence of chords in a pattern typical of an acoustic guitar player. A very small latency (strum_speed) emulates the short time delay between each string being plucked as the plectrum moves across all six strings. Width effects the width of the initial noise burst, with higher widths producing a brighter sound. Decay and cutoff set the amount of attenuation and filtering, respectively, in the delay feedback.

Here is the patch in action:


Download the patch for Pure Data here.

Linux Format praise Aspect

"Aspect has a wonderful GUI, a beautiful sound and is immensely flexible. If you love synths, this one is well worth the money."

And so concludes Linux Format magazine's devastatingly accurate review of very own semi-modular software synth plugin Aspect. Pick up the latest issue to read the full review (which also contains a short - and equally positive - write-up about String). Thanks Linux Format!

Manifold and Resound Audio Units crashing in Ableton Live 8.1.1 on Mac OS X

A particularily nasty bug can be found with the current public version of Ableton Live: Ableton Live will crash when adding either a Manifold or Resound Audio Unit to a track. The latest Live beta sees a fix for issue, but for those users who are loath to upgrade we recommend either using the corresponding VST plugin of Manifold or Resound, or performing the steps outlined here as a workaround.

For more information, consult the Ableton Forum post here.

Aspect 1.5.0 and audio samples; String 1.0.3 for Windows

A trifecta of news updates:

Aspect has now been updated to 1.5.0, which aside from all the bug fixes and improvements, also includes the vastly better oscillators that were previewed a few weeks back. Download it here.

Secondly, some audio demoes of various Aspect sample sounds have been posted on the Aspect page.

And finally, String for Windows has been updated to 1.0.3. This fixes a bug that seemingly only occurs under Sonar where notes are left hanging when the Transport is stopped. There is no reason to upgrade from 1.0.2 if you aren't using Sonar or witnessing this bug. Download here.

Sonar handles Transport stops slightly differently from other hosts. It's certainly not wrong according to the MIDI spec, but it's definitely unconventional. Instead of keeping a list of all playing notes and sending each a corresponding MIDI Note-Off when the Transport is stopped, Sonar just sends a single MIDI All Notes Off message. Any plugins that only respond to MIDI Note-Off messages and ignore MIDI All Notes Off message will manifest this hung notes problem. Aspect and String both handle this correctly since their most recent updates.

String 1.0.2 now released

Version 1.0.2, a minor update for String, is now available - download for the platform of your choice here. String 1.0.2 contains a fix for a problem where using Chorus Type 2 with a Depth of 100% could, in certain circumstances, cause some unpleasant digital noise to occur.

New oscillators preview

A sneak preview of some new oscillators. These have several advantages over the current Aspect oscillators:

• Reduced CPU usage: They use, on average, about 30% less CPU resources. When taking the rest of Aspect's synthesis path into account, this translates into approximately a 10% reduction in CPU resources for a patch.
  
  
• Reduced memory usage: Overall memory usage for oscillators is reduced by an impressive 80%, although this doesn't have much of an impact to the user.
  
  
• Reduced aliasing and foldover noise: Aliasing and foldover noise at the ultra high end of the frequency range is reduced to practically negligible amounts. Here are two examples. Note that these are unfiltered raw oscillator sweeps, so ensure that your volume is at an acceptable level.
  The first example is a sawtooth sweeping from the low to the high frequency range, and then back again:
  
  The second example is a pulse wave with a duty cycle of 50% sweeping as in the previous example:
  
  
  
• Removed DC Offset: There is no DC offset when sweeping the pulse-width of the Pulse waveform.
  
  
• Reduced Sync Folderover Noise: Aliasing that could occur during an oscillator sync is significantly reduced.
  
  
• Awesome sound: We can't quantify this one, so let your ears be the judge. Here are two raw sawtooth oscillator, with no filtering, tuned octaves apart. The pitch of one oscillator is slowly detuned relative to the other to introduce beating:
  
  

Loomer String released

Loomer String Synthesizer is now available for purchase and to demo: enjoy!

String is a dual layer, polyphonic string ensemble synthesizer available for Mac OS X, Windows, and Linux, in Audio Unit, RTAS, and VST Plugin formats, as well as in standalone application format. String's marvelous interface comes courtesy of freelance graphic designer Inquer. More information about String, as well as audio samples and a free trial download can be found here.

The trial version has the following demo limitations:

• User created Program and Bank presets can be saved, but not loaded back into the evaluation. They can however be loaded by a registered copy of String.
• Output will be periodically interrupted, approximately every 30 seconds, by a short moment of silence.
• Audio output will stop after 30 minutes of continuous use. String must be restarted to continue evaluation.

The trial can be upgraded to the full registered version by purchasing a licence for only £50 (+ VAT if applicable).