Preview Deck and related widgets are shown when no Headphones output is configured

[Paul Felts]

I'm using an external mixer, with a headphone jack and CUE buttons for headphone cuing. Mixxx's documentation claims that Mixxx can be configured to "External Mixer Mode," in this section from https://www.mixxx.org/manual/latest/chapters/configuration.html:

"External Mixer Mode
In this mode, Mixxx outputs the audio from each deck to a separate soundcard output. This allows you to route the deck outputs through a hardware mixer. To enable external mixer mode, select a valid audio output for the Deck outputs in Preferences ‣ Sound Hardware ‣ Output."

Deck audio is correctly routed through my external mixer and I can use the external mixer for headphone cueing of deck audio. However, I cannot listen to Preview Tracks. They don't get routed to the external mixer.

In External Mixer mode, with Mixxx connected to a 4-in / 4-out soundcard and selecting the soundcard's ch 1-2 and ch 3-4 as DECK 1 and DECK 2, Mixxx does not output Preview Deck audio to the external mixer, but instead seems to still expect a DJ splitter cable to be connected to the PC. I cannot select either of my soundcard's channels as HEADPHONE output in Soundcard Hardware, since Mixxx does not support assigning multiple outputs to a channel.

As a consequence of this functionality, I can not listen to Preview Decks at all through my external mixer, when my hardware is set up correctly for External Mixer mode. Connecting a second pair of headphones to another soundcard output and switching between headphones would theoretically allow me to listen to Preview Decks, but that doesn't seem like a solution.

* Hardware platform: Dell Latitude E6430 laptop
* Operating system: Windows 7 Pro 64 bit (6.1.7601), SP1, SP2 rollup, all updates applied
* CPU architecture: Intel Core (dual) i7-3520M @ 2.9Ghz, 2.9Ghz
* RAM installed: 16GB
* Video hardware: Integrated Intel HD Graphics 4000 (disabled), Nvidia NVS 5200M (enabled)
* Video drivers: Intel HD Graphics 4000 driver: version unknown, disabled
* Video drivers: Nvidia NVS 5200M driver version: QNF 385.08
* Sound hardware: integrated IDT high definition audio codec, GPU hosted Nvidia HD audio, ESI Maya44 USB+
* Sound drivers: IDT: 6.10.0.6491, Nvidia: 1.3.34.27, MAYA: 3.6.10
* Mixxx version: mixxx-2.1.0-alpha-pre-master-git6338-release-x64.exe

Steps to reproduce the issue can be added if needed. although the issue seems self explanatory.

[Be (be.ing)]

The Preview Deck is only sent to the Headphones output, so it cannot be used with an external mixer unless your sound card and mixer both have a spare stereo pair of channels, in which case it would probably make more sense to send another regular deck instead. I think the issue here is that the UI has no indication that the preview deck is not functional when there is no Headphones output configured. Mixxx could either hide all Preview Deck widgets from the GUI or pop up a dialog explaining that the feature only works with the Headphones output configured when the preview button is pressed in the library. I think it would be better to hide the features.

[Paul Felts (h-pa5l-v)]

Be: Thanks for your clarification. Perhaps, the Preview Deck could have a HEADPHONE Toggle, like the Sampler Decks. If the Preview Deck is only ever intended to be sent to headphones, I understand and this bug can be closed as intentional / won't fix. I suppose the fact that headphone output CANT be sent to an external mixer, without an additional soundcard output, would be out-of-scope for this bug report. If I'm dreaming of out-of-scope features, though, it would be neat if Mixxx could BUS / MUX multiple outputs to any single channel.

[Daniel Schürmann (daschuer)]

I am not sure what you are requesting. Which version of Mixxx you are using? Which external Mixer are you using?

If your External Mixer has three inputs CH1 CH2 and Aux, it will work quite good with Mixxx.
Use your Maya 44 for Left and Right Bus and connect it to your CH1 and CH2 mixer inputs.
Select your internal IDT sound for Headphone and connect it to your Aux input.

You can now always enable Aux PFL on your Mixer and use all Mixxx GUI PFL knobs and Library preview as usual. In addition you van also user the mixers PFL knobs to preview the decks.

If you does not have a Aux input on your Mixer, you may use just a second pair of headphones plugged into your PC to library preview.

Does it help your?

What else can we do to improve your situation?

[Be (be.ing)]

I am not aware of any DJ mixers that have an auxiliary input which can be sent to headphones but not the main output. That would just be another normal deck input. The Preview deck is a convenience feature for some users who prefer to use it with internal mixing. It is not at all necessary and the use case is already supported by previewing decks normally (personally I never use it). IMO the only problem here is that the GUI for the Preview Deck is shown when the user's hardware configuration does not support it without any explanation of why the feature doesn't work.

[Paul Felts (h-pa5l-v)]

Daniel: Thanks for the suggestion. You've been more than kind in indulging my questions. I don't want to waste any more of your time with this. I was just curious and I didn't understand the intended functionality of the Preview Deck. I understand now that the Preview Deck is intended for those without an external mixer. You can close this issue.

Be: Thanks for answering. I agree with you that Mixxx's UI is a bit unclear on the intended functionality of the Preview Deck. I look forward to future improvements. Thanks again.

[Be (be.ing)]

I have changed the bug title to reflect the issue better. It is indeed a user experience issue, but it is a minor one.

[ronso0 (ronso0)]

What about adding a hint like the one that pops up when trying to enable 'passthrough' although there's no vinyl/line input set up?

"
Preview deck uses headphones as output device.
You didn't configure any headphone device.
[Configure] [Cancel]
"

[Daniel Schürmann (daschuer)]

Good idea.

[Be (be.ing)]

I disagree. I find that dialog annoying. I think it would be better to hide parts of the GUI that are not functional with the user's configuration.

[Daniel Schürmann (daschuer)]

This is a question of consistency.

Currently it is implemented for vinyl control and microphone, that we can enable the widgets and the user is informed that it cannot be used via a pop up. It is somehow consistent to do it in the same way for headphones.

The other way round might be confusing because, all headphone related controls has to be hidden on a fist start, which are IMHO essential for DJing. Hiding them by default may through a bad light on Mixxx.

This is the case for the Booth output right now. This is a OK for me, because it is an advanced feature which the user will likely search in hardware preferences. But we can considerer to put the booth gain in the view menu and tell the user how to configure it when he tyres to enable the view.

All in all the arguments for "diabling vs. hiding" GUI elements applies, which can be found in various places on the web.

[ronso0 (ronso0)]

I agree with Daniel that hiding headphone controls is not a good solution.
A first-time user who has not yet set up the output devices properly may be irritated/disappointed by this basic feature missing. This might also happen if devices get messed up/removed between mixxx shutdown/restart.

However, the dialog should have a Cancel button and respective Preferences pane should not be force-opened (unlike Vinyl or Passthrough buttons react right now).

Headphone related controls could be greyed out, Preview deck waveform might have a label saying something like "Headphone device not configured" or graphical equivalent.
For booth controls I agree with Be, they should show up only if the 'special feature' device is enabled in hardware preferences.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8935