GNUitar
Guitar processor software
(C) 2000-2003 Max V.Rudensky <fonin@ziet.zhitomir.ua>
1. What is GNUitar ?
GNUitar is a real-time sound effects software that allows
you to use your computer as a guitar processor. It has GTK+ based
interface. It can be compiled on any flavor of UNIX that have
GTK+ 1.2, Glib, pthreads and OSS sound driver. It also works on Windows.
Program is inspired by 2 works:
o Ele 0.1 by Morris Slutsky
http://www-personal.umich.edu/~mslutsky/elepage/index.html
o Guitar FX Processor by Marin Vlah
http://fly.srk.fer.hr/~mvlah/fx_processor.html
GNUitar is free software and is distributed under GNU GPL license;
however you should pay to obtain Windows binary (you are still free
to compile it yourself; see section 10 "Legal Issues").
2. Download
http://freshmeat.net/projects/gnuitar
http://ns2.ziet.zhitomir.ua/~fonin/downloads.php
3. Requirements
You will need
o GTK+ version 1.2.6 or better; program was not tested with GTK 2.0;
o GLIB 1.2 or better
o POSIX threads on UNIX
o full-duplex sound card
o To compile: GCC on UNIX, Microsoft Visual C++ 6.0 on Windows
4. Performance
GNUitar is a CPU-consuming program. Pentium/166 is sufficient
to run GNUitar, Pentium II/300 is recommended, and on Pentium II/450
it will work just fine.
Real performance is very depend on your CPU/sound card/sound driver/OS
combination. The best performance can be achieved on Linux,
because of its great real-time features and advanced OSS sound drivers.
When running the program, make sure you close all unnecessary applications,
to give more resources to it. Avoid anything that can cause disk I/O
or CPU usage.
GNUitar runs with increased priority; this may cause hang-ups
and delayed system response on low-end machines. Therefore you
should care to save all important data in other applications,
before you launch GNUitar.
4.1 UNIX notes
GNUitar executable file should be setuid root to process sound with
real-time priority; otherwise you'll hear glitches and delays while
switching between windows. It switches to real user id as soon as
it set real-time priority to effect-processing thread, and before
any GTK initializations are being performed, so it shouldn't break
security on your system.
GNUitar has a latency of about 4-8ms on Linux/Pentium II/450/AWE64 ISA !
4.2. Windows notes
Windows have complex problems with latency when processing audio in real time,
mostly because of its non-uniform drivers architecture.
GNUitar latency on Windows is much higher than on Linux. The real latency
is very depend on sound board driver.
There are few kinds of sound drivers for Windows: old VXD (Win95/98),
NT4-kernel style, and modern WDM drivers that were introduced in Windows 98/SE.
Currently GNUitar uses common MME API (MME=MultiMedia Extension) that is
compatible with all kinds of drivers; however AFAIK WDM drivers provide
much lower latency. Therefore, avoid VXD drivers; use modern WDM drivers
instead, if possible.
The difference in latency between two kinds of drivers is really noticeable:
I had 100ms up to ~400ms on Pentium III/850/ISA AWE64/VXD,
and ~60ms on Pentium MMX/166/Yamaha OPL3/WDM laptop.
Try to re-launch GNUitar few times, if the initial latency is bad.
The kind of bus (PCI/ISA) of the sound card does not affect
the latency very much, the deal is with OS and its architecture.
So do not through away your old ISA Sound Blaster and replace it with
modern sound card, first try it on Linux !
5. Installation
See INSTALL file for common installation notes.
6. Interface and Controls
There are 3 areas in the main window. The right area is a list of all
available effects. The central area contains effects that are currently used.
There are few buttons right to it should be used to add/remove effects
and change its order. Each effect has separate top-level control window with
appropriate sliders. Each effect-control box is shown in the window manager
task bar.
The left area contains available effect layouts, or presets, and button
to add the one. Layout is a "snapshot" of your effects and its'
settings, you can load/save using "File" menu.
Big "Switch" button is used to switch layouts. In this manner,
you can change current sound by one mouse/keyboard click.
You can write track of what you play to a file. Just click
check-box "Write track" at the bottom of program window, enter
filename and play. Don't forget that continuous track write
can fill out your hard drive.
The track file format is raw data, word length, signed,
44100 Hz sampling rate, 1 channel. In the future, sampling format may change,
however you will always be informed about actual format.
You can convert it with SoX program like this
sox -w -s -c 1 -r 44100 track.raw track.wav,
and then to MP3:
bladeenc track.wav
Sox is available at http://home.sprynet.com/~cbagwell/sox.html,
and Bladeenc is at http://home8.swipnet.se/~w-82625.
Windows users can write track directly to .wav file
(currently it is not available on UNIX).
Autowah
speed - speed of wah-wah'ing
freq.low - low frequency (the cycle starts from this freq.)
freq.hi - high frequence (the cycle stops at this freq.)
mix - mix clean sound with processed sound
7. Effects
The controls and description of the effects are described below.
7.1. Reverberator
Reverberator produces echoed "space" sound. Controls:
delay - delay time
wet - "wet" (processed) sound volume
dry - "dry" (clean) sound volume
regen - number of repeats
7.2. Delay
Another kind of reverberation.
decay - this controls how the repeated sound is fading out
time - this is the delay time
repeat - number of repeats
7.3. Distortion
distort - power of effect
level - volume, for the case if you need to mute it quickly
saturation - high-frequency "sand" in the sound
lowpass - low-band filter that can be used to change the sound feel
7.4. Vibrato
Vibrato sounds like when you turn the master volume on and off very quickly
(few times per second).
speed - the speed of modulation
amplitude - the depth of modulation
7.5. Chorus
depth - the depth of modulation
speed - the speed of modulation
wet - "wet" (processed) sound volume
dry - "dry" (clean) sound volume
regen - hard to explain
7.6. Echo
Another reverberation effect, not like the others.
While other reverb effects are just kinds of sound patterns repeating,
echo attempts to achieve a large hall echo.
decay - this controls how the repeated sound is fading out
count - number of repeats
size - controls delay time
8. Bugs
Probably they are there :-) Send bug reports to fonin@ziet.zhitomir.ua
9. About Free Software Development
You should always keep in mind, that development of free software
doesn't work in the same way as commercial development. Every
successful free software project has an active userbase behind it. This
means that your comments, ideas and bug reports are extremely
important. If something doesn't work, or some feature is missing,
please mail me about it. Thank you in advance! You can send GNUitar
related mails to me at mailto:fonin@ziet.zhitomir.ua.
10. Legal Issues
GNUitar is a free software and is distributed under the terms of
GNU GPL license. However you should pay a small amount of $10 to obtain
Windows binary. You are still free to compile it yourself from sources,
or get a compiled binary from a friend. Please note that this does not
contradict with GNU concept, and it is not like the commercial licenses.
Paragraph 1 of the GPL license states: "You may charge a fee for the
physical act of transferring a copy, and you may at your option offer warranty
protection in exchange for a fee."
You are free to copy and share the program with other people,
you are not limited with the number of computers where you can use it.
You can redistribute the program and the works based on it
under the terms of GPL license. You have complete sources and detailed compile
instructions to build the program yourself, so you always have a choice
not to pay. You have full freedom with using and sharing the program,
according to the GNU software concept.
You may regard this charge as a charge for build service.
In return for quite a small amount you will get high-quality software
with full freedom to use and share it (compare it with commercial
guitar processors licenses and the hardware effects cost).
11. Order Information - Windows Users
To be done.
12. Related Links
http://freshmeat.net/projects/gnuitar and
http://ziet.zhitomir.ua/~fonin/downloads.php - GNUitar project pages
http://linux-sound.org - excellent categorized list of Unix sound software
http://home.sprynet.com/~cbagwell/sox.html - SoX playback/record/processing
software
http://home8.swipnet.se/~w-82625 - BladeEnc, free MP3 encoder
13. Author
Max Rudensky <fonin@ziet.zhitomir.ua>
<fonin@yahoo.com>
http://ziet.zhitomir.ua/~fonin
