Thanks for explaining and putting that in some perspective. If the sound card only supports 16 bit samples, which a lot of sound cards integrated into DJ controllers and computer motherboards do, how does that factor in?
Do you recommend that main & headphone gain knobs on controllers be mapped to Mixxx's software gains unless they act on the controller's integrated sound card? Some controllers do send MIDI/HID signals even if those affect the controller's integrated sound card. Even if there was a reliable cross-platform way to adjust sound card volume controls from Mixxx, it would still be confusing because some sound cards can only be controlled by a physical knob on the device. On 04/07/2016 02:05 AM, Daniel Schürmann wrote: > Hi, > > Be, I am sure your sound-card does the volume control just right. I > think all serious soundcards (and even onboard types) have a hardware > volume solution, that is of cause controlled by a digital signal. > > It will most likely look like Figure 1: > http://www.ti.com/lit/ds/symlink/pga2320.pdf#page=7 > Where the gain of an analog op-amp is controlled by an 8 bit signal. > This circuit is lowers the input signal INCLUDING the quantization noise. > > Mixxx cannot lower the quantization noise of its ouput signal, it is > just there. > The Mixxx master gain is actually just a bit crusher. > For example, if you lower the master gain to -20 dB Mixxx's 24 bit > output signal is reduced to ~20 bit. > The Signal to noise ration goes down from 144 dB to 124 dB (The noise is > amplified by 20 dB relative to the full scale) > However in this case, we are still better than the 96 dB of 16 bit CD rips. > > A ultimate solution would be to allow to map the soundcards volume > slider to the controller and Mixxx GUI. > This might be possible by "libportmixer" > > Kind regards, > > Daniel > > > > > > > 2016-04-07 0:45 GMT+02:00 Ferran Pujol Camins > <ferranpujolcam...@gmail.com <mailto:ferranpujolcam...@gmail.com>>: > > I see, thank you for explaining! > > > 2016-04-07 0:43 GMT+02:00 Be <b...@gmx.com <mailto:b...@gmx.com>>: > > All sound cards work differently, but I don't think it matters > whether the sound card has digital or analog gain. Either works > better with a stronger signal coming in. > > My sound card has digital gains and meters on the device, so I > can actually see whether the signal is at the same level to > confirm this. I just experimented turning the main gain in Mixxx > down with the sound card all the way up versus leaving the main > gain knob at unity in Mixxx and turning down the sound card. The > former definitely sounded worse than the latter. > > On 04/06/2016 05:19 PM, Ferran Pujol Camins wrote: > > I understand, but isn't the OS mixer just decreasing or > increasing the > volume digitally? In that case, if the OS mixer volume is > 100% (no > volume modification) and mixxx gain is 30% is the same than > Os mixer 30% > and mixxx 100%, am I wrong? > > 2016-04-07 0:13 GMT+02:00 Be <b...@gmx.com > <mailto:b...@gmx.com> <mailto:b...@gmx.com > <mailto:b...@gmx.com>>>: > > It's better to have Mixxx sending the sound card a > signal with a > high signal-to-noise ratio than turn the gain down in > Mixxx and send > a signal with a lower S/N ratio to the sound card. To > reach a > comparable volume, the signal would have to be > amplified somewhere > down the line (sound card, mixer, amplifier, or > whatever), which > would amplify more noise. Or to turn the volume down, > it would still > sound better to send a strong signal out of Mixxx and > attenuate it > further down the signal chain. > > > http://mixxx.org/manual/latest/chapters/djing_with_mixxx.html#djing-gain-staging > > On 04/06/2016 05:02 PM, Ferran Pujol Camins wrote: > > But why is it better? > > 2016-04-06 23:59 GMT+02:00 Be <b...@gmx.com > <mailto:b...@gmx.com> > <mailto:b...@gmx.com <mailto:b...@gmx.com>> > <mailto:b...@gmx.com <mailto:b...@gmx.com> > <mailto:b...@gmx.com <mailto:b...@gmx.com>>>>: > > > The gain in Mixxx controls the signal that is > sent to the sound > card. The OS mixer controls the sound card. > > On 04/06/2016 04:57 PM, Ferran Pujol Camins wrote: > > What's the difference between lowering the > volume in > mixxx and > in the OS > mixer? > > 2016-04-06 23:43 GMT+02:00 Be > <b...@gmx.com <mailto:b...@gmx.com> > <mailto:b...@gmx.com <mailto:b...@gmx.com>> > <mailto:b...@gmx.com <mailto:b...@gmx.com> > <mailto:b...@gmx.com <mailto:b...@gmx.com>>> > <mailto:b...@gmx.com <mailto:b...@gmx.com> > <mailto:b...@gmx.com <mailto:b...@gmx.com>> > <mailto:b...@gmx.com <mailto:b...@gmx.com> > <mailto:b...@gmx.com <mailto:b...@gmx.com>>>>>: > > > > I've been working on the wiki and > reviewing controller > mappings lately. > I did a little editing to the > language of the DJ > Hardware Guide > > > (http://mixxx.org/wiki/doku.php/hardware_compatibility ), > split the > custom caps section to its own page, > and revived > the old > headphones > section on its own page. > > In reviewing mappings, it has become > apparent that > there > should be > guidelines on how to handle main & > headphone gain > knobs on > controllers. > I added a section to the Contributing > Mappings page > > > > > (http://mixxx.org/wiki/doku.php/contributing_mappings#main_headphone_gain_knobs > ) with some guidelines and started a > new page > > > (http://mixxx.org/wiki/doku.php/operating_system_mixer ) with > information about adjusting sound > card levels. It > would be > great if > others could contribute details and > screenshots to > the new > Operating > System Mixer page. > > Two cases that I'd like to ask about > is when a > controller > has a sound > card without any gain controls or > doesn't have a > sound card > but does > have main & headphone gain controls. > In these > cases, should > the controls > be mapped to the software gains in > Mixxx or not? > If they > should be > mapped, then I think the controller's > wiki page should > advise users not > to use them in most cases and link to > the OS Mixer > page. > > I also split the Contributing > Mappings page into > smaller > sections and > put a bit more context in the > introduction. I added a > little section on > documenting how microphone inputs > work too. > > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Get Mixxx, the #1 Free MP3 DJ Mixing > software Today > http://mixxx.org > > > Mixxx-devel mailing list > Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net> > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net>> > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net> > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net>>> > > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net> > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net>> > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net> > <mailto:Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net>>>> > https://lists.sourceforge.net/lists/listinfo/mixxx-devel > > > > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Get Mixxx, the #1 Free MP3 DJ Mixing software Today > http://mixxx.org > > > Mixxx-devel mailing list > Mixxx-devel@lists.sourceforge.net > <mailto:Mixxx-devel@lists.sourceforge.net> > https://lists.sourceforge.net/lists/listinfo/mixxx-devel > > ------------------------------------------------------------------------------ _______________________________________________ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
