Sonic Charge Bitspeek RE User Manual
version 1.0
Table of Contents
..................................................................................Introduction! 3
.....................................................................User Interface Front! 4
.....................................................................User Interface Back! 5
.............................................Using Bitspeek with Stereo Signals! 7
...........................................................Bitspeek Versus Vocoders! 8
.................................................................Example Combinators! 8
.................................................................Credits and Contacts! 12
......................................................Copyrights And Trademarks! 12
Introduction
I N T R O D U C T I O N
Bitspeek is a real-time pitch-excited linear prediction codec effect. Right now
you are probably thinking, "oh, another one of those"? Or perhaps not. Chances
are that you have never heard about "linear prediction", although most of us
use it daily when we talk on our cell phones. Linear prediction coding is a voice
compression technology that appeared in commercial products in the
seventies and was implemented in some well-known speaking toys of the early
eighties.
We have applied this technology to create an audio effect that analyzes audio,
extracts a number of parameters (including pitch, volume and formant data)
and then resynthesizes the audio using a simple oscillator, noise and filter
architecture.
A number of playback parameters can adjust the pitch and tonal quality of the
sound. It is possible to play the pitch with MIDI notes and you can create
tempo-synchronized "formant freezing effects". Despite having only a few
simple controls, this box can produce a broad range of sounds from cheap
speaking toys to high-end vocoder and talkbox effects.
! © 2012 Sonic Charge! 3
User Interface Front
RATE (kHz)
Bitspeek performs its calculations at a designated fixed sample-rate, regardless of
the sample-rate your project is running at. The possible settings are 8 kHz, 11 kHz,
22 kHz and 44 -> 48 kHz (the last mode will actually adjust to the project sample-
rate and select a rate between 44 and 48 kHz). Notice that Bitspeek is still compati-
ble with any sample-rate by performing automatic sample-rate conversion.
RATE affects several other internal parameters in the DSP algorithms and changing
it alters the sound dramatically. (Notice that the 44 kHz mode will require more CPU
compared to the other modes. In many cases, the 22 kHz mode works just as well.)
FRAME RATE
The audio signal is analyzed and processed in blocks called "frames". For each
frame, Bitspeek estimates the pitch, volume, stereo image and formants of the in-
coming audio, as well as the balance between "voiced" audio (e.g vowels) and
"voiceless" audio (e.g., the noise in a consonant).
By lowering the frame rate, the analysis will be performed more rarely and you will
achieve a cheaper toy-like sound. You can also "freeze" the audio by dragging
FRAME RATE all the way down to 0. The parameter range is 0 to 80 Hz (if SYNC is
off) and higher rates requires more CPU than lower rates.
SYNC
Enable SYNC to make Bitspeek "freeze" frames in sync with the tempo of your mu-
sic. When SYNC is enabled, you may select various time synchronized rates (1/8, 1/
16 etc) with the FRAME RATE slider instead of selecting a rate in Hz.
KBD MODE
Enable this mode to control the pitch and envelope of the effect with your MIDI keyboard. When enabled, Bitspeek will play only when it receives notes and it will
transpose the pitch according to the notes it receives.
Start by creating a sequencer track for Bitspeek (e.g., right-click the device and
choose "Create Track for Bitspeek"). Turn down the TRACKING parameter to zero
to achieve a vocoder / auto-tune like sound.
If you set the FRAME RATE to zero (with SYNC disabled), Bitspeek will "freeze" the
formants on note on, allowing you to create interesting "stroboscopic" audio ef-
fects. Finally, Bitspeek supports Pitch Bend (one octave up and down) and the Sus-
tain Pedal can also be used to "freeze" frames while playing.
4! ! © 2012 Sonic Charge
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