Playback

The Player lets you listen to a recorded measurement, navigate through it, and compare two recordings by ear. It plays time-domain files (.hdf, .wav, .dpsa), shows a level meter and a calibrated sound pressure readout while playing, and can render the processed audio back to a WAV file.

Opening the Player

There are two ways to reach the Player:

Start Menu → Listening → Preview / Replay Workbench — opens the application in listening mode with the Player docked at the bottom.
The Player tab in the bottom dock, next to Recorder and Mark Editor. Click the tab at any time while working in the Analysis workspace.

Right-click the Player tab header and choose Properties to show or hide the right-hand REPLAY panel, which holds the File, Channel, Tacho, Channel mode and EQ settings.

Player Layout

Source File and Channel Selection

The source is set in the REPLAY properties panel, or by selecting a file in the data tree and choosing Player from its context menu.

Setting	Description
File	Read-only path of the current source. Use the folder button to browse for a `.hdf`, `.wav` or `.dpsa` file.
Channel	Picks the channel to listen to. For files with two or more channels an extra entry `ChL + ChR (binaural)` appears at the top of the list; choose it to play a binaural head recording in stereo.
Tacho	Optional reference channel (for example RPM or road speed). Its value at the current playback position is shown next to the level meter. Leave unset to disable the readout.
Channel mode	`L+R` both channels (default), `L` left only, `R` right only, `Mix` = (L+R)/2 sent to both outputs.
EQ	Listening equalization, see below.

The output device is chosen from the headphone-icon drop-down in the transport row. The list contains the active Windows audio outputs (the system default is marked [Default]) and, when connected, any DAQ front end that can act as a headphone output.

Transport Controls

Control	Function	Default
Round play button	Starts playback; while playing, stops it and keeps the position.	—
Time readout	Current position and total duration, in mm:ss.	—
Loop	Restarts automatically at the end of the file, or at the end of the selected playback range.	Off
Mute	Silences the output without stopping playback. The button turns red.	Off
Play to File	Records the audio you are hearing to a WAV file.	Off
A	Applies A-weighting to the monitored signal.	Off
Speed	Playback rate: 0.25×, 0.5×, 1×, 2×, 4×. Pitch changes with the rate.	1×
Gain slider	Digital gain from −30 dB to +30 dB in 0.5 dB steps. 0 dB = pass-through.	0 dB
Volume slider	Output volume, 0…100 %.	100 %

The Gain slider changes the signal itself and therefore also changes the level meter and the recorded WAV. The Volume slider only changes how loud it is in your headphones. Use Volume for comfort and Gain only when you deliberately want to raise a quiet recording.

Keyboard Shortcuts

Key	Action
`Space`	Play / stop
`←` / `→`	Seek 5 s backward / forward
`Home` / `End`	Jump to the start / end of the file
`Ctrl` + `←` / `→`	Jump to the previous / next bookmark
`B`	Add a bookmark at the current position
`L`	Toggle loop
`M`	Toggle mute
`R`	Start / stop Play to File
`1` / `2`	Pin the current file to slot A / slot B
`T`	Switch between slot A and slot B

Where the shortcuts apply

The four transport keys ← → Home End seek only while the focus is inside the Player page. Everywhere else those keys keep their normal meaning — navigating a list, a tree or a set of tabs, and resetting the axes in the Data Viewer. If a seek key seems to do nothing, click once inside the Player page and press it again.
No shortcut fires while the text cursor is in an input field. You can type a frequency or a time value containing the letters L, M, B, R or T without triggering the player.
When the focus is on a slider (Gain, Volume) or an open drop-down list, the arrow keys keep their own meaning and adjust that control instead of seeking.

Timeline, Playback Range and Bookmarks

The timeline shows the waveform envelope of the source in grey, the elapsed part of the file in the accent colour, and a round thumb at the current position. Hovering displays the time under the cursor.

Interaction	Result
Click or drag on the timeline	Seek to that position (continuous while dragging).
`Shift` + drag	Select a playback range. Playback stops (or loops) at the end of the range instead of at the end of the file.
Right-click the timeline	Clear the selected range.
`B`	Drop a bookmark (◆) at the current position.
Click a bookmark	Seek to it.
Double-click a bookmark	Add or edit its comment.
Right-click a bookmark	Remove it.

A dragged range shorter than about 50 ms is discarded, so a stray click while holding Shift will not accidentally trap playback in a tiny loop. Bookmarks that fall within 100 ms of an existing one are merged.

Level Meter, SPL and Tachometer Readout

Two horizontal bars show the left and right peak level. The bar runs green through amber to red as the level approaches full scale; the scale bottom is −50 dBFS.

Next to the meter, the level is also shown as a calibrated sound pressure level in dB SPL (RMS, per channel). The calibration — what a full-scale PCM sample corresponds to in dB SPL — is entered in the Mark Editor toolbar and is stored per file; the default is 114 dB SPL at full scale. A dash is shown when the signal is silent.

If a Tacho channel is selected, its value at the current playback position is shown next to the level, using the channel's own unit.

The dB SPL readout is only meaningful once the file has been calibrated. An uncalibrated recording is displayed against the default full-scale reference and the absolute numbers will be wrong, even though the relative changes are correct.

Listening Equalization

Binaural recordings made with an artificial head or a binaural headset are stored with the equalization of the recording chain. To hear them correctly over headphones, the replay chain has to compensate for that. The EQ drop-down in the REPLAY panel selects the target:

Option	Meaning
`None`	Pass-through — the samples are sent to the output unchanged.
`ID`	Independent of direction. Matches the intrinsic equalization of a binaural headset; effectively pass-through for such recordings.
`FF`	Free field. Applies the ID → FF difference filter.
`DF`	Diffuse field. Applies the ID → DF difference filter.
`HpEQ`	Headphone equalization slot, for a user-supplied headphone response.

For ordinary (non-binaural) channels the equalization is bypassed, whatever the setting.

Aurally correct replay needs no separate switch. When you select a connected DAQ front end as the output device, the player configures it for authentic level replay automatically, so what you hear reproduces the sound pressure of the original measurement.

A/B Comparison

Two recordings can be pinned side by side and switched instantly, which is the most reliable way to hear a small difference:

Load the first file and press Pin A (or 1).
Load the second file and press Pin B (or 2).
Press A ↔ B (or T) to switch.

Each slot remembers its own playback position, so switching resumes the other file where you left it. If audio was playing, it continues after the switch. The summary text next to the buttons shows which files are pinned and which slot is currently active (▶).

For a fair comparison, set the same playback range and the same Gain in both slots, and avoid changing the Volume between switches.

Play to File

The record button (or R) writes what you are currently hearing to a WAV file. The recording is taken after all replay processing, so the speed factor, equalization, A-weighting and Gain are all included — this is the way to hand a colleague exactly the sound you are describing.

Start playback.
Press the record button. A save dialog proposes a name such as vlisten-record-20260802_143015.wav.
Press the record button again to stop writing.

Play to File can only start while playback is running. It captures the processed signal, not the raw measurement data — do not use the resulting WAV as an input for quantitative analysis.

Tips and Notes

The playback position of each file is remembered, so reopening a long recording resumes where you stopped.
Changing the channel or the equalization does not start playback on its own; press Space or the play button.
Bookmarks are kept for the current session and are intended for navigating during a listening run.
If no output device is selected, the system default speaker is used.
At 2× and 4× the pitch rises with the speed, which is useful for scanning a long recording quickly but not for judging sound quality.