Voice Tweaker DXi

		Description
		Features
		Specifications
		Performance
		MIDI implementation
		Requirements
		Screenshot
		How does it sound?
		History

Description:

The Voice Tweaker DXi is a MIDI controlled pitch transposer designed for monophonic signals such as voice, spoken or sung, or solo instruments. It can transpose the pitch and formants independently, thus enabling both formant preserving pitch transpose and other more unusual effects. As a DXi plugin, it can be used in any DXi hosting application. such as Sonar or Fruityloops. Since the Voice Tweaker DXi is capable of generating multiple voices, creation of “instant choirs” from a single voice is quite possible (see the example at the bottom of this page).

What exactly is DXi ?

DirectX Instruments is what the acronym stands for. It is an extension to the DirectShow Media streaming platform (a.k.a. DirectX plugins) which makes it possible to control audio via MIDI events in perfect sample accurate synchronization with audio. This makes it possible to create software synths, MIDI controlled filters etc. which can be controlled by the host application. For further information go to the DXi info page.

If you are interested in making your own DXi plugin, check the DirectXFiles website. They provide an application wizard for Microsoft Visual C++ 6 with which you quickly can setup the framework for a DXi plugin.

Features:

		MIDI control of up to 16 voices with control possibility of modulation, formant, pitchbend, volume and pan (independently per MIDI channel). Control changes are real-time, i.e. not connected to a MIDI note-on event.
		Amount of MIDI “correction” settable.
		LFO with 6 waveforms, settable frequency for ALL waveforms (incl. noise).
		Settable reference frequency (middle A)
		Mix processed signal with original.

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Specifications:

		Up to 16 voice maximum (as much as your CPU allows, see below).
		Handles 16 bit and 24 bit (32 bit float) audio formats
		44.1 kHz to 96 kHz sampling rates supported (tested at 44.1/48/88.2 and 96 kHz)
		Pitch detection range 50 Hz to 1000 Hz
		LFO Frequency: 0.01 to 20 Hz
		LFO Waveforms: Sine, Triangular, Square, Saw positive/negative and Noise.
		LFO Modulation: 0 to 1200 cents
		LFO Offset: -100% to +100%
		Reference Frequency: 420.0 to 460.0 Hz
		Output “equal power” mix of processed and original signal.

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Performance

Performance measured in Sonar.

Processor

CPU load @ 16 voices
and 44100 Hz samplerate

Intel Pentium II 400 MHz

~75 %

Intel Pentium III 800 MHz

~32 %

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MIDI implementation

Function...

Receive

Remarks

MIDI channel

1-16

See below *)

Note number

0-127

Velocity

Note On

x

Use channel volume **)

Note Off

x

Pitch Bend

o

Control Change***)

1

o

Modulation

3

o

Formant -12 to +12 semi, with 64 = 0 semitones

7

o

Volume
with 100 = 0 dB and
0 = -100 dB

10

o

Panpot, 64 = center

o = yes, x = no
*) Voices played by MIDI notes on a specific MIDI channel are all affected by the Pitch bend, Modulation, Formant, Volume and Pan setting for that MIDI channel. In order to control voices individually, they must be played by MIDI notes on different MIDI channels where each channel has its own Pitch bend, Modulation, Formant, Volume and Pan setting.
**) As a signal input controls the actual volume, responding to note velocities doesn’t make much sense. However, the overall volume can be set (per MIDI channel) with controller 7.
***) Control changes are real-time, i.e. NOT connected to MIDI note events.

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Requirements:

		PC equipped with Pentium II 266 MHz or higher, 64MB RAM. 5 MB free Hard Disk space.
		DirectX 8 installed (includes the DirectShow component needed for plugins).

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Screenshot:

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How does it sound?

To examplify the operation of the Voice Tweaker DXi, you can here download an example of
the MIDI features. Original file is taken from the Voice Tweaker review on The DirectXFiles
site and is processed in Sonar 1.0 with some MIDI chords.
The corresponding BUN file is also available if you want to play with it!

Original “We all get a little crazy sometimes...” (size 43 KB)