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Audio Quality Testing – initial tests

This one’s a long time coming, and there will be more posts on this topic. Go ahead and start playing this playlist to hear the, good the bad and the ugly (It will only take a minute).

So I took some time today to do some testing using some microphones laying around.

Testing methodology:

  1. Zoom (It’s common enough) and they use pretty good codecs that are rarely a bottleneck.
  2. Local recording (I’ll do WAN impact simulations at another time).
  3. I did use the Original microphone sound mode (Not all conference systems have noise suppression and it’s worth noting that noise suppression while good for many cases does reduce quality). I’ll test these capabilities with actual noise another day (Crying baby and firetruck simulator?).
  4. I haven’t tested every microphone in this house yet (I’ve got a sure SM58, a steel series headset my wife uses, and i’m sure some other bluetooth devices).
  5. I tried to not adjust the gain on any devices, or the audio input volume (Which shows on the analog earbuds which are way to quiet). Simulating someone joining a call late and in a hurry.
  6. The AC came on at one point and I tried to note it, but it’s hard to hear it too much. There is a NAS and desktop (fairly quiet fans) and the laptop fan. I plan to do another test with music, firetruck/baby in background to simulate some of the COVID WFH lifestyles.
  7. I ate dairy (tends to give me some sinus congestion) and drank a lot of diet Dr. pepper. Both of these always negatively impact my throat etc for speaking. Drinking water, standing, and avoiding dairy would make me speak better, but I was going for something more realistic.
  8. I use the following test phrases:

Oak is strong and also gives shade.
Cats and dogs each hate the other.
The pipe began to rust while new.
Open the crate but don’t break the glass

Realistically it woulds be better to read something a lot more mundane, but these are known test phrases that have a diversity of sounds.

About what I tested:

  1. The Heil PR-40 microphone was attached to a Blu USB-> XLR adapter with no XLR cable used. Gain was a bit high.
  2. Razer Nari (Note I don’t have their crazy audio tools installed, like most software built by hardware companies I find it to be an absolute nightmare to use). These headphones use proprietary 2.4Ghz wireless. and not bluetooth.
  3. Apple AirPod Pros. Note while they are connected to a Macbook Pro, I had 2 other bluetooth devices (keyboard, touch pad connected) so a non-optimal codec was likely used. Again, trying to simulate minimal effort real world, what a worse case Bluetooth codec would sound like. Remember the audio quality on Bluetooth is often 10x worse for the microphone than the sound input so just because you hear “good” sound doesn’t mean your transmitting it.
  4. PSTN bridge. I dialed into the zoom call (not the app) using an iPhone 11 Pro. I tested this twice, once holding up to my ear and another on speaker phone laying on my desk. I should probably test using the app, but I wanted to simulate the ugly truth of what it sounds like when people use the dial in code under semi-optimal conditions. (I get good phone service, and wasn’t in a car with the AC blasting).

I’ll post some more information later (gotta run to the bank), but here’s a playlist of my initial tests.

Do you own tests:

  1. By no means accept my testing as authoritative. Do your own test and customize for
  2. The room you use
  3. The devices you want to use
  4. Try adjusting with volume, gain and other settings.
  5. Try standing (it helps some people speak more clearly).
  6. Have someone else listen to them.


Audio quality is often the result of many factors that are out of our control like:

  1. Bad wifi
  2. cheap gear
  3. background noise
  4. People who still use Lync/Skype4Buisness.
  5. Accents (Myles, if I have 2 trees, and add 1 tree how many trees do I have?)

Still despite this it’s worth knowing what you sound like and doing some quick tests to see if you can make yourself heard more readily. Being clearer on calls leads to less repeating things, more understanding and hopefully shorter/faster and more productive phone calls.

Lastly to the Managers out there. Talk to your reports about audio quality. Get people gear, get people an Ero WIFI bundle, reimburse better internet. A team who’s well heard is a team that is productive.