USB Headset Measurement

How do you measure USB headsets? In this short video, we demonstrate how to measure USB headsets using SoundCheck. You’ll see how to configure digital input and output channels, set up the headset in the hardware editor, and perform measurements including left and right earphone frequency response, THD, sensitivity, and microphone performance. This method can be used for any USB audio device, making it easy to accurately evaluate both playback and recording performance.

Watch this Video Demo of Measuring a USB Headset

Learn More about USB Headsets

• • USB Headset Input/Output Test Sequence: https://www.listeninc.com/resources/test-sequences/usb-headset_input_output_sequence/

Video Transcript: How to Measure USB Headsets

Today I’m going to demonstrate how we can measure a USB headset using SoundCheck. We’ll test both the left and right ears and the microphone.

SoundCheck supports both analog and digital inputs and outputs, so to test a USB headset, all we need to do is plug it into our computer’s USB port and configure a new digital channel in the hardware setup, then we can test it just like a conventional headset. 

Let’s review our setup. We’ll use a head and torso simulator to capture the headset’s response, and I’m powering that with a SoundConnect 2 power supply. The microphones within HATS transmit the signal to the computer via the AmpConnect 621 Audio Interface, and that also has a built-in amplifier to power the HATS mouth, which we need for the microphone test.

First, I’ll configure the USB headset in SoundCheck. We do this in the Hardware Setup. You can see here we already have the input and output channels of the AmpConnect 621 configured  – it’s full plug and play so that happens automatically. 

I’ll plug the USB headset into the USB port of my laptop. In the hardware editor, I’ll right click to create an input channel. I’ll set it to use the Windows WDM driver, and now it shows me all the available devices. We see the headset mic there – let’s set the type to digital. Since it’s digital we don’t need to enter anything in the calibration field. I’ll leave the sampling rate as the default, as my audio interface is using this value. We’ll also do the same for the outputs. We’ll set the driver and pick the device, there’s 2 channels so we’ll set these to left and right, and again it’s a digital device. 

First we’ll measure the headphone response, and we’ll use the USB headset test sequence that’s available for free on our website. 

When we open our sequence, it prompts us to re-link the signal paths used in the sequence. Let’s add them to system calibration.

And now we need to assign hardware channels and calibration files. It’s warning me that the signal paths I just added don’t have associated hardware channels and calibration data, so we’ll click through all of those so we can add them. Here’s our signal paths.

We’ll assign signal paths digital out 1 and 2 to USB Headset out L and R. Since these are digital outputs the calibration is unity digital out

Now we’ll do the same for the input headset sequence. We’ll set Digital In 1 to the USB headset and calibration to unity digital in

Let’s just do a quick check and make sure all our signal paths are correct. It’s looking good

So now we’re all set up and ready to measure. 

Let’s hit start. 

The sequence plays our test stimulus, and it gives us the left and right frequency response, and also the THD for the left and right earphone. Over here we see the waveforms, the left and right recorded response, and down here we calculate our average sensitivity. Sensitivity is a useful production line test to confirm that the average level across a bunch of headphones is reasonably stable. If the sensitivity swings dramatically in either direction from sample-to-sample, it can indicate a quality problem in manufacturing. We also show the left/right tracking – that’s the difference in sensitivity between the left and right ear over the frequency range.

Now we have some results, let’s take a look behind the scenes at what our test sequence is doing.

We’re using a Stweep that sweeps from 20 kHz down to 100 hertz at 12th octave resolution. This is a compound stimulus with a very short, 1kHz pilot tone, before the Stweep. The pilot tone isn’t analyzed, but we use it in this frequency shift step here  to align the time and phase of the response signal with the stimulus before we analyze it.

This feature ensures accurate analysis. It compensates for any unknown phase differences that are introduced from the stimulus and response being played through different hardware devices – the stimulus is played through the laptop via USB, and the response is recorded through our audio interface.

Next, our analysis step compares the stimulus waveform with the frequency-shifted version of the response waveform to get the fundamental. There’s also a post-processing curve averaging step that calculates the average sensitivity.

Lastly, the display step that defines what graphs and results are shown. So that’s the earphones, now let’s test the microphone. We’re already connected and set up, so I’ll tell the sequence to continue and measure the microphone.

So that’s the earphones, now let’s test the microphone. We’re already connected and set up, so I’ll swap over to the microphone test sequence and measure the microphone.

We heard our test stimulus coming out of the HATS mouth, and being recorded by the headset microphone. And here we can see the frequency response and sensitivity of the microphone.

And if we look at the sequence, we can see it’s very similar to the headphone. We’re using an 8 Khz to 100Hz test stimulus, again with a trigger tone to align our stimulus and response waveforms. We have our frequency shift calculation, just like before. Then our analysis step to calculate  frequency response, and also a post-processing step to calculate sensitivity. And of course we have a display step to determine what is shown on screen.As you can see, because SoundCheck supports any combination of analog and digital audio devices, it’s very simple to measure a USB headset. All you need to do is make sure you have it set up as a hardware device in SoundCheck, and use a compound stimulus and frequency shift step to align your waveforms before analysis. You can measure any other USB connected audio device in the same way. Check out our website to learn more and download the SoundCheck test sequence.