FYI, I added the following since http://nielsmayer.com/envy24control/mudita24-1.0.1.tar.gz ... shall I release a 1.0.2 with the following additions (?): * fixed --card and --device to allow valid ALSA names and numbers ( https://bugzilla.redhat.com/show_bug.cgi?id=602900 ). * Add display of "Delta IEC958 Input Status" under "Hardware Settings." * Updated and corrected manual page and README Before I release, I'd like to know what happens on cards that don't have this feature, or if it's universally supported, but badly named. Can those with a Terratec or other card test the following command and let me know the results of command "amixer -c M66 cget iface=MIXER,name='Delta IEC958 Input Status'" e.g.: >> amixer -c M66 cget iface=MIXER,name='Delta IEC958 Input Status' >> numid=50,iface=MIXER,name='Delta IEC958 Input Status' >> ; type=BOOLEAN,access=r-------,values=1 >> : values=on ................................................................................................. Also, in case anybody ever wondered what this one, under "Analog Volume" is for: "Volume Control Rate Register" I added it to the README: ......................... Notes on the Envy24's hardware Digital Mixer and hardware Metering, by Niels Mayer ( http://nielsmayer.com ): -------------------- The "Monitor Inputs" and "Monitor PCMs" tabs contain multiple scale widgets grouped into L/R pairs and an associated peak-level meter. Each scale widget represents the 24 bit attenuation value of each input to the ice1712-based soundcard's digital mixer. This mixer is typically used for zero-latency monitoring of "live" inputs, alongside backing sounds and effects coming from the eight channels of PCM feeding the digital mixer. When many inputs are "hot" simultaneously these scale-widgets attenuate the inputs going into the digital mixer to prevent the output from clipping. For details see http://nielsmayer.com/npm/envy24mixer-architecture.png (from http://alsa.cybermirror.org/manuals/icensemble/envy24.pdf ) This is what the above manual says about the Envy24's digital mixer: > 4.5.5 Multi-Track Digital Monitoring > > The Envy24 integrates a 36-bit resolution digital hardware mixer. The > width of the data path is strictly to ensure that during processing of > all the channels, under any condition, no resolution is lost. The > dynamic range of the end user system will be limited by the range of the > physical output devices used. In order to maintain identical gain to the > input stream (i.e. 0dB), the resulting 24-bit is not msb-aligned to the > 36-bit. The overflow bits correspond to the analog distortion due to > saturation. The user would need to reduce the overall attenuation of the > inputs to avoid clipping. Insertion of the digital mixer adds only a > single sample cycle delay with respect to the original data. This > extremely low latency all digital mixer provides monitoring > functionality and can replace a traditional external analog input > mixer. There are 20 independent audio data streams to mix and control > the volume. Adjustment of responsivity vs. "zipper noise" from the 1.5dB steps at the top-range of the digital mixer attenuators is achieved by the following control under "Hardware Settings": > MT3B: Volume Control Rate Register > ... > Volume update rate control (sampling rate, PSYNC) > This register allows gradual change of the digital mixer volume > setting. The value in MT3B specifies the number of samples to elapse (in > hex) between each 1.5dB increment/decrement in volume mixer. This gradual > volume update continues until the setting programmed into MT38 is > reached. The appropriate value to program may vary, but 00 or 01h are good > choices for most cases. The peak metering data is displayed as 0 to -48dBFS in envy24control's meters. This data is derived from the envy24's hardware peak metering: > Peak data derived from the absolute value of 9 msb. 00h min - FFh max > volume. Reading the register resets the meter to 00h. This resolution of the hardware metering is descibed by Fons Adriaensen in a mailing list discussion: http://lists.linuxaudio.org/pipermail/linux-audio-dev/2010-August/029009.html > [...] You have 128 steps between 0 and -6dB... > And even at -24dB the next step is 1.3dB lower. Below that > it gets worse radipdly. For a meter that is just supposed > to keep a check on peak levels it's OK. Note that hardware metering data is also available from the command-line: > amixer -c M66 cget iface=PCM,name='Multi Track Peak',numid=45 > numid=45,iface=PCM,name='Multi Track Peak' > ; type=INTEGER,access=r-------,values=22,min=0,max=255,step=0 > : values=63,62,51,49,56,60,63,62,59,54,0,0,0,0,0,0,0,0,0,0,113,112 .................................................................... Niels http://nielsmayer.com _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
