Mixxx Vinyl Pass-Through (And Pitch-Shift)

[MattMik]

Hello, everyone!

My name is Matt, and for Google Summer of Code, I'm proposing the implementation of a vinyl pass-through feature to Mixxx. This would allow a user to instantly switch from vinyl control mode to pass-through mode in order to send the audio from a normal vinyl record through Mixxx, and to the output of one of the Mixxx decks. In fact, vinyl control mode wouldn't even have to be used: pass-through does not require the use of timecoded vinyl.

I have a few questions as to what everyone would like to see happen with this feature. When vinyl pass-through is enabled, obviously the software pitch control cannot modify the actual speed of the record, as that is determined by the setting of the pitch control on the actual hardware turntable. But, would users prefer if the pitch control modified the pitch of the input, in effect creating a tempo-independent pitch shift? Or would having to manage two pitch controls (one in software, one in hardware) be too much of a hassle for the user?

Second, how would everyone prefer vinyl pass-through be activated? Obviously, one of the methods is through a simple button. A more interesting approach would affect vinyl control mode. It might be possible to modify vinyl control mode to automatically turn on vinyl pass-through when the signal quality of the input signal is less than a certain percentage quality, and disable vinyl pass-through when it's greater than this percentage. This would allow a DJ to enable and disable vinyl pass-through without having to press a single button: just put the appropriate record on your deck, and you're good to go. There are downsides to this method, though, but such a feature could always be disabled by the user in preferences.

If anybody has any comments or feedback, or any suggestions for additional features, please let me know!

Thanks!
Matt

[DJ Julia]

Hi Matt,

here you find some background to this bug/missing feature: https://bugs.launchpad.net/mixxx/+bug/355945

If you are going to implement it, for the control I'd avoid any automated system like the signal quality, just put a button on the main interface next to the waveform as it's done in Traktor Scratch. Don't hide it in some menu, it's something that will be used frequently so I think the best place to control it is from the main interface on the deck as Traktor does.

See the attached pic: the yellow "thru" button on deck 1 is what Traktor uses for this purpose. On the deck 2 you see a grey B. By clicking on the yellow thru or grey B you can change from timecode to pass thru and viceversa.

Regarding the signal quality, bear in mind that if for any reason the quality of the signal degrades while the record is playing on the main output of the mixer and the software switches to pass through mode then the crowd will hear a loud whistling noise and the DJ will look like a giant a**hole

Regarding the pitch: only the turntable/cdj should control the pitch, no control from the software, it would create confusion. In Traktor the pitch control is automatically disabled when in timecoded mode, you can only do temporary pitch bend (like nudging the record) from the software. The DJ that uses timecoded vinyl is generally not keen on touching the computer too much, so most of the action would take place on the turntables/CDJ and external mixer, the laptop would be more like a big box full of music, effect generator and sync-helper.

Cheers
J

[Cutwerk]

I agree having used Traktor at my friend's house this would be an excellent style of implementation. I currently use a mixture of DVS and real vinyl, and have to use splitter cables to send the signal back from the souncard to the phono inputs of a mixer, this makes setup that little bit more complicated, and more cables = more cables to go wrong!

Also, as many mixers now have switchable inputs for line/phono, this would effectively give me another two inputs on a two-channel mixer, so I could run a drum-machine or CDJ in there, which would be real handy. I don't know much about coding but if there is any way I can help getting this feature off the ground then please let me know!

[ywwg]

Matt is working on this feature for Google Summer of Code