Qu Drive Stereo Recording/Playback
|| UTILITIES | Qu Drive | Stereo
Record or playback stereo audio to/from USB-A storage.
ⓘ USB-A audio/data and SD card recording/playback features utilise the same system resources and cannot be used at the same time.
Stereo Recording
The top section of the screen is for recording to USB-A storage and includes level meters for the channels being recorded, recording controls and elapsed/remaining time.
- Patch the channels to be recorded to USB output sockets 1&2 in the I/O screen.
- Press the Record button to start recording.
- Press the Stop button to stop recording.
Stereo recordings are stored in the AH_QU\USBREC folder on the drive.
Stereo Playback
The bottom section of the screen is for playback of audio from USB-A storage.
The Qu can playback stereo files that were recorded from the Qu to the AH_QU\USBREC folder on the drive, or mono/stereo, 44.1/48/96kHz, 16/24bit *.WAV files which have been copied to the AH_QU\USBPLAY folder.
Select Track - Select the track to be played from Playback or Recordings folders.
Transport Control – Use to Play/Pause, Stop or skip to Previous/Next. Use the circular playback position marker to jump to a specific point in the track.
Playback Mode (bottom right) – Options include Play All (and stop), Play Single (and stop), Repeat All (loop through all tracks) and Repeat Single (loop a single track).
ⓘ When using Play All or Repeat All playback modes, tracks will playback either in the order they were recorded, or in the order they were copied to the drive.
Record/Playback Priority
Stereo USB playback signal will be sent to the dedicated stereo USB Input channel as well as USB input sockets 1&2 and take priority over signal from the USB-C audio interface. When stereo recording/playback is in progress, it is not possible to use SD card record/playback or store/recall data from USB storage.
Folders, files and formats
The USB device must be formatted to FAT32 before use. This may need to be carried out using a computer, before then formatting again using the Qu to ensure the correct folder structure.
ⓘ Format connected storage in the UTILITY > USB Utility > Status/Format screen.
Recordings are stored to the AH_QU\USBREC folder.
Stereo recordings are made to stereo interleaved 24bit uncompressed *.WAV files, at the sample rate set in the SETUP > Audio > Sync&USB screen.
The Qu can playback mono/stereo, 44.1/48/96kHz, 16/24bit *.WAV files from the AH_QU\USBPLAY folder.
Buffer Usage
Buffer usage meters indicate the performance of the connected storage device. If buffers are filled, data will be lost and an error will be counted.
Length of recording
The maximum length of a stereo recording is determined by the maximum file size of 4GB, which equates to approximately 2 hrs at 96kHz or 4 hrs at 48kHz.
Qu Drive Multitrack Recording/Playback
|| UTILITIES | Qu Drive | Multitrack
Record or Playback individual signals to and from individual channels using an SDHC card.
ⓘ USB-A audio/data and SD card recording/playback features utilise the same system resources and cannot be used at the same time.
ⓘ SD card recording and playback modes are exclusive, it is not possible to record and playback simultaneously.
ⓘ Meters switch automatically to show either signal being recorded or played.
ⓘ Only recordings matching the current USB/SD sample rate are available for playback.
Qu Drive Multitrack Controls
Select Track - Select a multitrack recording for playback.
Transport Controls – Use to Record, Play/Pause, Stop and skip to Previous/Next. Use the circular playback position marker to jump to a specific point in the track.
Playback Mode (bottom right) – Options include Play All (and stop), Play Single (and stop), Repeat All (loop through all tracks) and Repeat Single (loop a single track).
Qu Drive Multitrack Recording
- Patch any channels to be recorded to USB output sockets in the I/O screen. Only patched channels will be recorded.
- Set Input Direct Output source to choose whether channel processing will be recorded for any Input Direct Outputs that have been patched.
- Press the Record button to start recording.
- Press the Stop button to stop recording.
Multitrack recordings are stored as separate folders in the SD Card AH_QU\USBMTK folder.
Number of channels
The maximum number of channels which can be recorded depends on the speed of the SD card and the sample rate of the recording. For best results, use an SDHC card with UHS-I and Class 10 markings.
Qu can record or playback up to 16 channels at 96kHz or up to 32 channels at 48kHz.
Record/Playback Priority
Multitrack playback signal is sent to the digital source for individual channels and takes priority over signal from USB-C. When multitrack recording/playback is in progress, it is not possible to use Qu Drive stereo record/playback or store/recall USB data.
Folders, files and formats
The SD card must be formatted in the Qu before use.
ⓘ Format connected storage in the UTILITY > USB Utility > Status/Format screen.
Recordings are made to the AH_QU\USBMTK folder. Each recording is stored in its own sub folder as a collection of mono 24bit uncompressed *.WAV files, at the sample rate set in the SETUP > Audio > Sync&USB screen.
Files are named with the channel number they were recorded from combined with the channel name. e.g. ‘03SnrTop.WAV’. The channel number of the file is the USB input socket number it will be routed to when playing back a multitrack recording.
Buffer Usage
Buffer usage meters indicate the performance of the connected storage device. If buffers are filled, data will be lost and an error will be counted.
Length of recording
The maximum length of a multitrack recording is determined by the maximum file size of 4GB (for each mono channel recorded), which equates to approximately 4 hrs at 96kHz or 8 hrs at 48kHz.
USB-C Audio/MIDI interface
|| METERS | USB/SD
The Qu’s USB-C Audio/MIDI interface is class compliant and conforms to USB 2.0 standards. It is recommended to use a high-speed USB cable for connection. Depending on the environment the system is being used in, it may also be beneficial to use a cable which includes a ferrite bead.
ⓘ Note that not all USB 3.0 ports are fully backward compatible with USB 2.0 – for best results, it is therefore recommended that a USB 2.0 port is used where available. Where unavailable, USB 3.0 ports utilising xHCI host controller drivers should be avoided as many are known not to support the isochronous transfer method used for streaming audio.
Connecting to a Mac
The Qu is Core Audio compliant so no driver is required, and it will appear as both an audio and a MIDI device when connected.
Connecting to a Windows PC
Visit the Allen & Heath website (www.allen-heath.com/resources) to download the latest Qu Windows ASIO/WDM driver.
Follow the instructions to install the driver before connecting the Qu.
Connecting to other devices
It is possible to connect the Qu as an Audio/MIDI interface to any device which supports Class Compliant devices, including tablets and phones, though it is not possible for all devices to be tested and officially supported.
USB Stream Mode
The USB-C interface can be switched between Stereo and Multitrack stream modes in the SETUP > Audio > Sync&USB screen.
Multitrack mode provides all 32 input and 32 output sockets to the connection and is intended for use with a DAW or when using USB for insert processing.
Stereo mode uses only USB input and output sockets 1&2 and presents itself as a stereo device for compatibility with tablets and phones for live streaming or background music playback, or for a simple stereo recording/playback setup with a computer.
Sample rate
The Qu USB sample rate should be set in the SETUP > Audio > Sync&USB screen before any programs or apps accessing the USB-C connection are used.
96kHz – Higher quality, lower latency, larger files recorded, lower SD card channel count.
48kHz – Lower quality, higher latency, smaller files recorded, higher SD card channel count.
Routing notes
- It is important to note when patching that outputs from the computer are USB input sockets on the Qu and USB output sockets from the Qu are inputs on the computer.
- The dedicated stereo USB channel on the Qu is always sourced from USB input channels 1&2.
- By default, USB output channels 1&2 are fed from the Main LR mix, though all USB patching is fully assignable.
- When using WDM drivers to utilise the Qu for Windows system/default sound, multiple pairs of USB channels are available for use. To make use of all 32 input and 32 output channels, the ASIO driver must be used with a compatible program like a DAW.
- When selecting the Qu as the default output audio device on a mac, USB channels 1&2 are used by default, though this can be changed in the Audio MIDI setup.