American Audio Vms2

American Audio VMS2

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• Manufacturer's product page, provides manual and drivers for download.
• Forum thread, for discussion of mapping options.
• Latest controller mapping, which this wiki page describes.

The American Audio VMS2 is a 2-deck all-in-one controller. It is a USB class compliant MIDI and audio device that works with GNU/Linux, Mac OS X, and Windows. It features a 4 channel input and 4 channel output sound card with 2 phono preamps. The main output has XLR and RCA outputs (do not use both at once). There is a separate RCA booth output. The VMS2 can also be used as a stand-alone mixer with analog sources without a computer by setting the USB/Analog switches on the front of the device to "Analog".

Audio Setup

Because the sound card is USB Audio Class compliant, it works on GNU/Linux, Mac OS X, and Windows without needing to install any special drivers. However, on Windows, it is recommended to install the driver from the manufacturer to be able to use the ASIO sound API.

Unlike most controllers with built in sound cards, which rely on Mixxx to do all mixing in software, the VMS2 mixes signals from the sound card in hardware. To use it with Mixxx:

• Bypass the built-in hardware equalizer of the VMS2 (i.e. use Post-EQ Mode). Hold the forward search button on the right deck as you turn the VMS2 on to switch between Post-EQ and Pre-EQ modes. See section 15 of the manufacturer's manual for details.
• Set the USB/Analog switches on the front side of the VMS2 to "USB"
• In Mixxx's Sound Hardware Preferences:
• Set the sample rate to 48000 Hz
• Select channels 1-2 for Deck 1 output
• Select channels 3-4 for Deck 2 output

Note: You cannot use the preview deck to pre-listen in this setup, as Mixxx routes the preview deck directly to the headphone output, which is not mixed with the Deck 1/2 outputs. You could use a separate soundcard and route the headphone output there to also pre-listen using the preview deck. Of course, if you do so, attach the headphones to that other soundcard instead of the VMS2.

Input and Recording

The analog inputs are captured by the built-in soundcard as input signals. They can be used for timecode signals (e.g. timecode vinyl), as the VMS2 also features built-in phono preamps. FIXME I did not try that, please verify!

The microphone input is mixed directly into the master output signal of the VMS2 in hardware and cannot be captured through software. If you want to record voice over using the Mixxx software, you will need a different solution. You can use a separate microphone attached to the computer, but that signal will not be routed to the VMS2 and therefore not be on the VMS2 master output (but in the Mixxx recording from the software master/record output).

Mixxx's Deck 1/2 outputs are affected by the Mixxx software EQs. However, the VMS2's volume faders and crossfader (as well as the headphone buttons) control the VMS2's hardware mixer and do not affect Mixxx's Deck 1 and Deck 2 output signals. Therefore, a recording using the Mixxx software will sound different from what is played through the VMS2 master output, as the crossfader curve and signal mixing are not the same in hardware and software. If you require a recording that captures exactly what the audience will hear, use a separate soundcard and recording software to record from the VMS2 booth output.

MIDI Mapping

Mixxx Versions / History

The VMS2 has been fully mapped for Mixxx by the community. Different versions of the mapping exist. Most of them are linked somewhere in the Mixxx VMS2 forum thread. As of Mixxx 1.11, two mappings were included with Mixxx: the first one by Groschi, and a second, called "(Alternative)" by snu (that's me ;-)).

Groschis mapping mapped the controls also found on the VMS4 for the VMS2. The rotary knob in the middle section was left unmapped. The "Alternative" mapping improved on that by mapping all controls. The rotary knob was used for library browsing. It also featured EQ kill buttons on the secondary IN/OUT/RELOOP buttons and an obscure way switch between scratch mode and pitch mode.

As of January 2016, a new mapping has been proposed and a pull request is filed (see Links section). If everything goes well, it will be shipped with Mixxx 2.1.0, and replace both older mappings.

Mapping Description

This description is for the latest VMS2 mapping, currently available in a pull request against master (see Links section). This is currently only a 2 deck mapping.

Main Mixer Section and Headphones

All main functions are mapped straightforward:

VMS2 Control	Mixxx Control
Crossfader	Crossfader
Volume Fader	Volume Fader
Cue (PFL)	PFL
Cue Mix	Cue Mix (PFL / Master)
Headphone Gain	Headphone Gain
Channel Gain	Channel Gain
Master Gain	Master Gain

Deck Control

Deck control is straightforward, too:

VMS2 Control	Mixxx Control
Play	Toggle deck play/pause
Pause	Pause the deck
Cue	Cue Point (configure behavior in software)
Pitch +/-	Temporary pitch bend +/-
Pitch Fader	Pitch Fader
Range (Shift+Sync)	Cycle pitch fader range (+-8/10/30/100%)
Sync	Sync to other deck
Search <</>>	Search through currently loaded track
Keylock (Shift+Vinyl)	Toggle pitch independent time stretch (KeyLock)
Vinyl	Toggle between Scratch mode and Pitch mode
Platter	Touch sensitive platters! Scratch or Pitch

If you touch a platter in scratch mode, the track will stop there immediately! The backlight of the Vinyl button lights up when in scratch mode. When in pitch mode, touching the platters is safe.

Library and Track loading

Use the rotational knob in the center of the controller to browse through the library. Press the rotational knob to switch between library main window and sidebar. Unfortunately there seems to be no way to expand entries in the sidebar through the controller script.

Use the [LOAD] buttons to load the currently selected track into either the left or right deck.

The four directional buttons around the knob also control the library:

Button	Library function
Up	Previous library entry
Down	Next library entry
Left	Previous sidebar entry
Right	Next sidebar entry

If you hold Shift and then rotate a platter, you can scroll through the library much faster (but not as precise). This is sometimes handy to scroll through very long library lists. However, as you should organize your tracks in crates and playlists or simply use the library search function to filter the list, this might be remapped to something different in the future (maybe faster skimming through very long tracks).

Equalizer

The per deck EQ rotaries are mapped to their software counterparts. The VMS2 has no dedicated kill switches for the EQ. However, in Mixxx it has (using the secondary Loop controls)!

VMS2 Control	Mixxx Control
Shift+IN	Kill Switch Lo
Shift+OUT	Kill Switch Mid
Shift+RELOOP	Kill Switch High

Hot Cues

The VMS2 features 6 Hot Cues per deck.

VMS2 Control	Mixxx Control
1 / 2 / 3	Set/Jump HotCue 1 / 2 / 3
Vinyl + 1 / 2 / 3	Delete HotCue 1 / 2 / 3
4 / 5 / 6 = (Shift + 1 / 2 / 3)	Set/Jump HotCue 4 / 5 / 6
Vinyl + 4 / 5 / 6 = (Vinyl + Shift + 1 / 2 / 3)	Delete HotCue 4 / 5 / 6

The controller script tries hard not to confuse Vinyl/KeyLock and HotCue actions. So deleting HotCues should neither toggle KeyLock nor Scratch Mode.

Loops

VMS2 Control	Mixxx Control
IN	Mark beginning of loop
OUT	Mark end of loop
RELOOP	Leave / Reenter current loop
LOOP	Start a 4 Beat loop from current position
Smart (Shift + Loop)	Toggle beat grid snapping
(:2) / (*2)	Halve or double the current loop length

As Mixxx currently only supports one active loop per deck, the secondary loop controls have been remapped to EQ kill switches.

Soft Takeover

The soft takeover feature shall prevent software controls from making sudden jumps, when hardware and software controls got out of sync. A hardware control needs to be moved close to were the software control is, before hardware control changes are also applied in software. While the idea is nice, it does not always work reliably, especially in hectic situations when controls are moved very fast. Soft Takeover has therefore been disabled for all controls in the mapping. If you want to re-enable it, just search for "soft-takeover" in the mapping XML file and uncomment the option. Soft takeover will probably be a required feature for 4-Deck support.

4-Deck Support

As of Mixxx version 2,0, it is theoretically possible to control 4 decks by using the redundant [PAUSE] button as deck switch. Unfortunately, this has not been mapped, yet. Stay tuned for updates or get coding!

The 4 Deck routing for this controller is of very limited use, as the volume- and crossfader directly influence the sound output in hardware.

• Route Mixxx "Left Bus" to the VMS2 output channels 1-2 (Left Deck Stereo).
• Route Mixxx "Right Bus" to the VMS2 output channels 3-4 (Right Deck Stereo).
• Bypass the built-in hardware equalizer of the VMS2 (i.e. use Post-EQ Mode).
• Route the headphone output to a separate soundcard.

In this mode, you cannot use the built-in headphone jack to pre-listen, as the Mixxx software controls for deck volume already affect the signals going into the VMS2. You need a separate soundcard to attach your headphones.
The two decks on the same bus are always directly affected by the volume fader, therefore you cannot fade between two tracks playing on the same bus without going over a point of silence. The faders are pretty much useless in that setup as they cannot be used intuitively.
FIXME The left and right bus are also affected by the software crossfader! That is bad and possibly wrong, as it means the hardware and software crossfader are both applied. I need to file a bug report (and link to it from here)!

Effects

The VMS2 does not have enough spare buttons and rotaries to control effects. It is probably best to use a dedicated effects controller for that. In theory it would be possible to overlay the library search rotary and the direction buttons around it, but this requires some scripting effort and may be confusing, as the direction buttons do not have backlights.