<html>
<head>
<title>GNUitar - Frequently Asked Questions</title>
</head>
<body>
<br>
<b>Q:</b> Program does not work; it produces some error message
like "Cannot open input/output sound device"<br>
<b>A:</b> Make sure your sound card driver is installed properly. Also make sure
that your sound card is full-duplex, and full-duplex mode is supported
by the driver.<br>
Another reason may be that your sound card does not support
the default sampling parameters of 44100 Hz/16bit/mono (which
is possible only for ancient sound cards :-)
Press "STOP" button, go to menu -> Options, open the options dialog and
try to set different parameters.<br>
<br>
<b>Q:</b> It seems GNUitar works, but I can't hear effects applied
to my guitar sound. "Clean" sound of the guitar is send to the speakers,
but with no applied effects. I hear native noise of effects, and it
seems like there is zero input signal send to effects.<br>
<b>A:</b> Make sure your line input or microphone input levels are not zero.
Use your OS mixer program to adjust input levels.<br>
<br>
<b>Q:</b> I hear both clean and processed signal in the speakers.<br>
<b>A:</b> Press "mute" checkbox on the line input channel in your mixer program
to suppress clean sound.<br>
<br>
<b>Q:</b> GNUitar noises terribly !<br>
<b>Q:</b> The output signal is over-amplified/distorted !<br>
<b>A:</b> The trick is with the levels of signal.
You should adjust your mixer properly. Set the line input to maximum level,
wave out and master volume to middle level, and then start to decrease
master volume until the noise will become minimal. Increase volume
on your external amplifier.<br>
The reason of problem is that some soundcards have poor signal/noise ratio
in full-duplex mode.
To eliminate noise, you may do the following:<br>
<ul>
<li>use protected cable to connect guitar into the PC;</li>
<li>ground your PC properly;</li>
<li>there is a possible noisy card (video/modem/LAN) on the motherboard
next to your soundcard. Try to move sound card as far as possible
from it.</li>
<li>try to use high quality low-noise pre-amplifier BETWEEN your guitar
and PC. Please be extremely careful with the volume control of
your pre-amp -- the sound card can be damaged if you set loud volume
on the pre-amp. The main goal of pre-amplifier is to decrease
signal/noise ratio between the signal will be passed to sound card.
Please understand that the program processes both signal and noise,
and the noise in the output is just the input noise amplified and
distorted by effects.</li>
<li>use the effect "sustain" as a pre-amp. Set "Gate" and "Sustain"
parameters to 100%.</li>
</ul>
<br>
<b>Q:</b> The latency is poor. Is there a way to improve it ?<br>
<b>Q:</b> How do I fight the buffer overruns ?<br>
<b>Q:</b> How do I achieve the best performance ?<br>
<b>A:</b>
<ul>
<li>The lower is the sampling rate, the better is the latency. Drawback is
the sound quality.</li>
<li>The lower is the fragment size, the better is the latency. Drawback is the
higher system load.</li>
<li>The hearable periodic scratches (DirectSound output) can be fixed
by decreasing the overrun threshold (sampling params dialog).</li>
<li>Increase the fragment size and decrease the sampling rate on
low-end CPU, to gain the best latency/overruns/load ratio.</li>
<li>On Windows, prefer WDM drivers, if possible. Try both MME and
DirectSound playback; choose which is the best.</li>
<li>Prefer Linux over Windows. Properly tuned Linux kernel has 10-100 times
better latency on the same hardware.</li>
<li>Make gnuitar executable setuid root on UNIX, to allow it run with
increased priority.</li>
</ul>
</body>
</html>
distrib
>
Mandriva
>
2010.0
>
i586
>
media
>
contrib-release
>
by-pkgid
>
56da1a6579789fd38c485d0a2ead8ebf
>
files
>
11
