There’s a great buzz in our open-plan office and I can often hear 3 or 4 conversations going on around me. The energy is terrific and it’s a great, collaborative environment, but it doesn’t come without its down side.

We love GoToMeeting and use it several times a day for XenApp development, but with the background noise in the office, it can be tricky hearing my meeting above other conversations. There had to be a solution; I was sure of it. So, I spent a few months searching for the best audio hardware and evaluated various kinds of headphones, microphones and audio interfaces and learned a few things. It turned out to be quite a long journey with some missteps. Now, I’m getting great sound for me and the others listening to me.

Here were my goals:

  1. Other people in a conference can hear me clearly and don’t get distracted by other conversations going on around me.
  2. I can hear people on the call clearly even with high background noise.
  3. I can hear what I’m saying so I can tell if I’m mumbling.
  4. The equipment is comfortable for long meetings.
  5. I can listen to music with the same equipment without distracting those around me.

Headsets

Over the years, I have tried various headsets and found them to either be cheap and nasty, or expensive with lots of money going on marketing. I didn’t want to compromise or waste money, so I was pleased to find an article on “making your own” gaming headsets which really helped. I already had a lovely pair of Bose QC25 noise cancelling headphones so I added a AntLion ModMic 4.0 uni-directional microphone, which attach like this:

modmic-qc25-attached

Or detach instantly:

modmic-qc25-detached

The ModMic consists of a magnetic clasp that sticks on to the headphones, and the boom can be flipped up or detached. A great piece of industrial engineering! At £40 it may seem quite pricey and there are cheaper lapel or headsets available. I’ve used two for a year and have had no trouble apart from when I managed to destroy the 3.5mm plug (though it was easy to solder a new one on the end); mind you I’m a klutz and break a 3.5mm plug every year or so, usually on aeroplanes. 🙂

Sidetone/foldback

My next problem was that with highly isolating headphones, I found it hard to talk when I couldn’t hear myself, so I wanted to get a good foldback sound. Maybe I’m more aware of this than most people since I have done live sound mixing for bands on hundreds of occasions over the years. Musicians love to hear what they are playing or singing clearly; it is an important part of producing a good performance.

Therefore we go to great lengths to get people good mixes for their in-ear-monitors (earphones) or foldback wedges. In the telephony world this is known as sidetone and according to Wikipedia it has been used in telephony since the 19th century. With digital audio we are still learning this, and I’m not the only one to get frustrated by the absence of sidetone:

Software sidetone

One way to support sidetone would be for software to play the user’s voice back to them. However, hearing yourself with more than a few milliseconds of latency is problematic; it can be really off-putting.

I tried LineIn on a Mac, which didn’t work too well, probably because the record and playback rates never quite match, so you often get samples building up and a distracting echo.

It is possible to get usable software sidetone below the 10ms end-to-end range with pro-audio hardware with VST drivers and the a professional Digital Audio Workstation package such as Ableton Live. That’s expensive and awkward to integrate with software on Windows such as GoToMeeting that is using the default Windows audio stack. Even a few milliseconds of delay  is perceptible because of comb filtering with the sound of your own voice versus what you hear via bone conduction.

Hardware sidetone

I have a SoundBlaster Live PCI card from about 2001, and it has a sophisticated hardware mixer built in. However, I wasn’t able to get drivers working on recent versions of Windows, and solutions involving PCI cards aren’t very portable. Sadly, when I evaluated a few recent consumer-grade audio interfaces and found the feature missing on many of the latest USB and PCI express audio interfaces.

So, I figured I’d try a little external mixer. Headsets typically use unbalanced 5 volt bias microphones with 3.5mm plugs. I didn’t find a good off the shelf solution to interface those to external mixers which typically use balanced XLR connectors with 48 volt phantom power, though there are some circuit diagrams available if you want to build your own hardware. If you try that please let me know how you get on. Antlion have announced an XLR modmic which I’m keen to try when it becomes available.

Eventually I found a recommendation for the Behringer UA302 and ordered one:

mixer

This is a great value (I paid £35). That 3.5mm headset socket top right works pretty well with the ModMic, and I can even roll off the bass a little on my voice to deal with the proximity effect of a microphone right in front of my mouth (which tends to make voices sound boomy). It is quick to adjust my voice sidetone independently of the conference call general volume. For music, I can flip the Modmic out the way and the audio quality (and volume!) from the UA302 is pretty good. The sound quality is not as amazing as my hifi amp at home but I’d rate it 8/10.

Impressions

I’m delighted with this rig and the sound quality I’m getting with GoToMeeting. The QC25 is a great sounding pair of headphones and the noise cancellation and comfort is remarkable. In pro-audio or hifi terms the QC25 is not the best thing around in an ideal environment but in a noisy office the noise cancellation is by far the most important single biggest factor for sound quality. Plus, I can run conferences and music at low levels and protect my hearing.

Sidetone really helps me speak clearly. Many people don’t like the sound of their own voice and once I got over that I get instant feedback on my enunciation, which is important to me since I tend to mumble. Frequently people mute themselves during our meetings and will then try and contribute to the meeting without unmuting themselves which can harm the flow of the meeting. With the hardware mute switch blocking the sidetone I know immediately if I’ve muted myself at the microphone since I can’t hear what I’m saying and so deal with it very quickly.

For quieter environments

Normally, I find gadgets disappointing; however this rig has worked so well, I got another (with Beyer Dynamic DT770-Pro headphones) for use at home. In that case, I went for the omni-directional version of the modmic, figuring it was quiet at home so the more even frequency response of an omni-directional capsule than the uni-directional version would be problematic.

I regret that since the omni-directional modmic pick up some of the sound coming from the open backs of the DT770s and the uni-directional version would have been better for that. It probably is possible to manage without sidetone in quieter environment but I’m hooked on great sidetone now.

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