Using AudioTools Wireless

AudioTools Wireless is an app that can be used as a remote audio input and output device for AudioTools running on another iOS device linked by WiFi.

We call the device running AudioTools (or another supported Studio Six Digital audio analysis app) the "host", and we call the device running AudioTools Wireless the "client".

In addition to sending digital audio to the host, ATW also sends calibration data, so that the analysis app has the same calibration as the sending device. A mic that reads 94.0 dB on the AudioTools Wireless client will also read 94.0 dB on the AudioTools host.

AudioTools Wireless also includes an SPL Meter and a Generator that function locally whether or not you are linked to another device.

Setting Up AudioTools Wireless

The only setup required on the AudioTools Wireless client is to calibrate any microphones that you are using, and to make sure you are connected to the same WiFi network as the host device.

We do recommend that you turn off the cellular network on the device (if any), by turning on Airplane mode, and then turning WiFi back on, and also force-quitting any background apps, especially apps that use audio or network data, to get the best performance.

Also make sure that your host device is only running one Studio Six Digital app, and force-quit any unneeded apps on the host device as well.

You can set the audio latency range by tapping the WiFi icon on the AUdioTools Wireless screen. Select Shortest if you are running on a very clean WiFi network, and have fairly new (faster) iOS devices. Select Default in typical conditions, and select Safest if you are having problems with the signal, as indicated by frequent re-buffering or communications errors.

Linking the Host Device to AudioTools Wireless

To connect the device running AudioTools (or another compatible Studio Six Digital app), just bring up the Input Source page, which is accessed from the Setup page on any module. Then tap the Link button, and select the AudioTools Wireless client that you wish to connect to from the list. This device name will be shown on the screen of the device running AudioTools Wireless.

When connected, you will see the word "Remote:" before the name of the input device, on the host screen. In most cases, you will also see an indication of the latency in ks (thousands of samples) and the number of errors encountered. It is normal for the latency value to vary as the app runs. If it runs out of data, or builds up an excessive amount of data in the audio buffer, it will re-buffer to get the latency within the desired range. The range for this value, and thus the latency, can be set on the AudioTools Wireless client, by tapping the WiFi icon.

Remote Generator

Another feature of AudioTools Wireless is a generator that is controlled by the host analysis device. The generator in ATW will follow the generator controls in the analysis app, including downloading and playing back sample files.

If you do not wish to have the AudioTools Wireless device playing sound, you can disable the remote generator function on the Streaming page, accessed by tapping the WiFi icon on the client device running AudioTools Wireless.

Calibration

If you are using the internal iOS device mic, it will be using the normal default calibration, based on the client device type. In most cases, this will be within a few dB in the mid-range frequencies.

If you are using iTestMic, the internal stored calibration will be used, so no calibration is required.

If you are using iAudioInterface2, follow the normal calibration procedure on the client device. If you have calibrate iAudioInterface2 with a mic on AudioTools, you can just copy the calibration values into the Microphone Setup page on AudioTools Wireless.

Mic Compensation Files

The name of the mic compensation file used, if any, will be sent to the receiving device. The file must be present on both devices for this work. In the case of the iOS mics, and iTestMic, this will already be the case. If you are adding your own file, make sure you add it to both devices.

Sample Rate

It is important that the sample rate on both devices is set the same. In most cases, this will default to 48kHz. If for some reason your client device is operating at 44.1kHz, set the host device to 44.1kHz, on the Settings-General page on that device.

Latency

Since we are sending audio over a WiFi network, we have to maintain an audio buffer so that we don't have glitches in the sound. Due to small differences in clock speeds, over time the latency can drift. We monitor the latency and try to keep this between a range, based on the Latency setting on the AudioTools Wireless Streaming page.

Background and Sleep Mode

AudioTools Wireless does not run in the background. When you exit the app by pressing the menu button, it stops running. To conserve the battery, you can press the power button to turn off the display. The app will continue to run, and uses very little power.

Limitations

Many audio analysis tasks are not affected by the kind of latency that using a WiFi link creates, but some cannot be used. Also, modules that directly access the hardware also cannot be used.

This list shows modules that have been tested and are working well. A * means that the module may have compromises in its operation due to latency or possible re-buffering. A ** means that the module is not expected to perform properly.

SPL Meter
SPL Pro
SPL Graph*
SPL Traffic Light

RTA
FFT
ETC* (external mode only)
Impulse Response
Smaart Spectrum
Transfer Function** (variable latency)

Line input modules will not work remotely.

Auto-ranging will not work remotely.