Lyrebird APP User Manual

Overview

The Lyrebird APP is a versatile, flexible Audio Processing Platform (APP).

It provides the capability to filter, process, enhance your audio. The Audio can be aggregate from manydifferent interface, all commonly used audio interfaces in a professional or user environment.

It receives the audio on many different interfaces, process it and sends it to almost all audio output interfaces in parallel.

Lyrebird APP is also enriched by additional features useful to control your audio device, e.g. an integrated web server or using UART in order to change configuration, settings and volume.

Main Features

Lyrebird APP comes as standard version or as Ultra version which provides additional features, including professional audio interfaces (AES3).

Any audio input can be routed to any output interface. In general, with some exceptions, all audio output interfaces are active simultaneously (no need to select output, just input).

Audio formats

Currently, all is 16bit audio sample based. 44.1 or 48 KHz are supported as sample rates. Future version of the Lyrebird APP firmware will support even 24 or 32 bit, at least 32bit for internal audio processing. Additional sample rates will be also possible.

The Ultra version supports also Sample Rate Conversion via hardware (SRC). Bluetooth with the Ultra version is an optional hardware upgrade, as well as WiFi for control or potentially for audio transfer, too.

Connectivity matrix

Please, see the drawing below for all the potential audio input and output relations. Please, bear in mindthat many output interfaces are active in parallel.

Figure 1: Lyrebird APP audio input and output options

The GUI systemLyrebird APP comes with an LCD plus Touch Screen which is used in order to control the device, to select features, to adjust volume or filters etc.

Main Welcome Screen

The main welcome screen acts already as user interface to select the audio interfaces (where to get the audio from), the sample rate or to configure where the audio should be sent to (headphone or speakers mainly to select, other output interfaces are active by default).

Figure 2: the main welcome screen

The dark green interfaces (BT, SPDIF rear, TOS rear, AES3 rear) are only available and able to be activated on the Ultra version (with additional DIGI-FP hardware interface).

Please, select the settings from top to bottom: choose Sample Rate first, then if output on HP

(headphone/line out) or SPKR (internal loud speakers), as last the audio input interface, e.g. USB.

Please, see the small icon in upper left corner. A tap on in will open the system configuration menu.

Configuration Screen

The system configuration, major options, are stored in a non-volatile way via onboard QSPI flash device. In order to see, change and save the system configuration – please tap on the small icon in upper left corner of the main screen. This menu will be displayed:

Figure 3: the configuration screen

Many of the options are stored on a non-volatile memory (QSPI flash device), so that they are active automatically on the next Restart or power cycle.

Remark:The auto start config setting is not active in FW version 1.1.0.

The USB options, is USB is used as Audio Interface or to manage the files on the SD card (visible as USB storage device) is never stored.

You can save the current setting or after some changes done via the Save button.

If you exit this window via the close icon (upper right corner, the red X) – all changes made are active but not saved permanently. They are lost with a Restart or power cycle.

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The Main Audio Screen

Figure 4: The main audio screen

Peak Meter

The Peak Meter shows the peak volume of the output audio (after processing), independent of any volume setting.

The Peak Meter acts also as volume control for the headphone (HP) or speaker (SPKR).

FFT Display

You can change the type how to display (dots, bars, line) via the Config Menu.

There are two “hidden” buttons: if you press on the most right or most left corner of the display – it changes the “window function” used for the FFT (Rectangular or Hanning window).

If you tap the display in the center – it will freeze. So, you can see a frozen graph, read the values etc.This tap can act also as a re-synchronization of the audio, e.g. for the ETH network audio to start a newsynchronization for the audio. This tap can be used if the audio has started to sound “strange”.

The values displayed on the right hand side have the following meaning:

• the highest level (in [dB]) of one of the frequency bins where it is seen

• the SNR of the audio signal

• the CPU Load (in percentage, more for debugging purposes)

• the active sample rate in Hz

Remarks:

The FFT suppresses the DC part and very low frequencies (they contribute most to the graph).

The graph is auto-scaled: it it adjusted automatically for the largest frequency bin (magnitude) to be displayed, so that it fits to the screen size. It results in: if no signal, just noise, it can look like a veryy strong signal. Please, see the magnitude (in [dB]) which should tell you that the signal is very weak.

The FFT window function is changed via most left or right taps on screen. A Hanning Window (left tap)results in more accurate values, but more “smeared” frequency bins (looking wider).

If the web browser is active or the ETH network audio was selected, the IP address of the web browser or the IP address of the Audinate DANTE audio stream found is displayed as white IP address in the upper center part of the screen.

The SD Card Player Screen

Figure 5: The SD card player screen

You can store WAV files (not MP3) on SD card. If they have the file extension *.WAV, they will be shown in the file menu.

The format for the WAV file should be (currently): 16bit, 44.1 or 48 KHz, stereo.The SD Card WAV Player will check the audio format of WAV file selected and just play it if it is supported. The sample rate will be set automatically (44.1 or 49 KHz).

Remarks:

The SD Card WAV player screen is quite limited (not a main feature of Lyrebird APP). Only the first 24files found on root directory are shown. Sub-directories are not supported (yet).

You can:

1. select a file y tapping it: a green box appears around the file name

2. change the selecting by tapping another file, moving your finger etc.

3. The selected file (green box around a file name) can be played: press the Play button on top.The screen will change to the Main Audio Screen.

4. If file played from SD Card – then the left User Button will open the SD Card player screen again. So, you can Stop, Pause or select a new file.

5. the Pause will stop and another Play will continue

6. The Stop button will stop playing a file. A new file must be selected.

7. The Play button pressed or the Exit button (the X in upper right corner) jumps back to the Main Audio Screen. All other taps and buttons remain inside the SD Card player screen.

Remark:

In order to manage the files on the SD card:

• on Lyrebird APP (not Ultra) – you can remove SD card and manage on a PC, reinsert again afterwards

• on Lyrebird APP or Lyrebird APP Ultra – in the Config Menu is an option for USB. If you select to mange SD card (no USB audio then), you can use the left USB interface and connect to a PC. The Lyrebird APP will appear on PC with a USB storage device. This is the one where you can mange files on SC card using a PC, without to remove the SD card from Lyrebird APP.

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Remote Control InterfacesYou can control the audio settings, the volume, etc., remotely via:

• USB UART (VCP) connection

• integrated Web Browser

Figure 6: The USB UART VCP display (via TeraTerm)

UART configuration parameters:

• Baud rate: 115200

• data format: 8 bit

• stop bits: 1

• parity: none

• flow control: none

Please, enter 'h' as command (followed by newline, carriage return) in order to see the list of available commands.

The + and – as command (plus Enter) increases or decreases the audio volume on headphone (HP) or speaker (SPKR).

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Figure 7: The internal web server page displayed by your host browser

Remark:The web browser is not active (even selected in configuration screen) when the SD Card WAV player isused as audio source or the ETH network audio is used.

You can configure to use:

• DHCP (get automatically IP address in your local network)

• or static IP address (as 192.168.1.200)

for the IP address of the Lyrebird APP internal web server.

You can increase (UP) or decrease (DOWN) the volume of the audio output on headphone (HP) or speaker (SPKR). The volume of other audio interfaces, e.g. S/PDIF Out, is not changed.

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Network AudioThe currently supported network audio format is Audinate DANTE. Lyrebird APP can act as a (passive) receiver or monitor in such a network (uDANTE).If there is an audio stream in your local network, between an Audinate DANTE player, e.g. DANTE Virtual Soundcard (DVS) and a receiver, e.g. Focusrite Rednet AM2, this audio stream can be found. The Lyrebird APP is able to listen to such Audinate DANTE audio stream and to forward to any of the output devices.

But Lyrebird APP is not (yet) a fully compliant Audinate DANTE device: it cannot be discovered (not visible in DANTE controller) and it cannot send audio into the network (yet).

Remark:The internal web browser is not active if the ETH network audio is selected as audio source (exclusive use of network).

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USB AudioThere are two exclusive options to use the Lyrebird APP in combination with USB Audio:

• If USB Audio is an input for the Lyrebird APP (sent from a PC) – it can be selected on the MainWelcome Screen.Remark: an USB audio device will show up after the USB was selected as input

• If USB is not used as audio input interface – then Lyrebird APP acts automatically as a USB streaming device. The audio is also sent to the USB port so that it can be received on a PC (as input on a PC).

The audio format (16bit) and sample rate (44.1 or 48 KHz) for the USB device on PC must match with the selected sample rate on the Lyrebird APP.Please, make user that on both sides the same sample rate is used.

Remark:If you have selected in Config Menu to use USB in order to manage the SD card – all USB audio (in and out) are not enabled, not possible to select and use.

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Test Tone Generator

There is a simple sine waveform generator, to generate a test signal coming out on the audio interface.

Currently, a sine wave, 1 KHz with full volume is generated. Future versions of the Lyrebird APP firmware will come with much more advanced features, e.g. so select other frequencies, wave forms and to adjust the volume.

Bluetooth Audio

Bluetooth Audio will be supported only on the Lyrebird APP Ultra version. It requires a hwardware module, a hardware upgrade. The hardware module itself will not be free of charge (but the firmware upgrade will be).

WiFi Audio

Currently, audio is not received or transmitted via WiFi.

It is possible to use Google Chromecast Audio (as WiFi audio). This external device can be send the audio via analog Line In to the Lyrebird APP or on the Ultra version even via optical TOSLINK.So, you can use also Internet and WiFi audio on the Lyrebird APP.

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Lyrebird APP, Torsten Jaekel, Sept. 2016