On Audio Input

I’ve just spent far too long playing with cables, audio inputs, microphones and so on. I need to be able to record good-quality audio for my video tutorials for CoreMelt (Gadget, Luminous, Shatter) and Creative Cow (Tilt Shift in Final Cut Pro).

To date, I’ve been using my Røde Stereo Videomic (SVM), plugged into my Canon HV20, in DV mode, connected to the Mac Pro via FireWire going straight into FCP’s Voice Over tool as DV Audio. Phew. Audio’s been pretty good (and improved from the first movie I did) but it requires processing. Since I generally have to work near my Mac, I have to make sure the area is free from small children. Since the SVM is so sensitive, it’s pretty easy to pick up background noise like birds or passing motorbikes. Noise reduction in Soundtrack Pro does work, but it can be difficult to get consistent results over several takes.

So, looking for a higher quality solution. The thing about audio is that once you’ve heard good audio, you don’t want to go backwards. I’m lucky enough to have nice headphones and a pretty good home theatre system. I’m not going to listen to pro audio friends’ gear as that’s just the path to madness and bankruptcy.

Some background. For a long, long time, Macs have only had line-level input — not mic level input. You need either a pre-amp to lift the mic up to line level, or a USB (cheap) or FireWire (expensive) audio interface of some kind to access the mic directly. So, what did I try?

1. The setup listed above. A hassle. Only goes into FCP (which is OK).

2. The SVM, plugged into the HV20, cable from headphone to line-in. Noisier than going through DV. Still a hassle to set up.

3. Singstar microphones with USB adapter. Sound quality is OK but not great. Adapter has long plugs so it’s hard to plug anything else in there. Nasty noise and too quiet when used with the SVM and a longer cable.

4. Altec Lansing USB adapter from a headset that subsequently died. (Shows as C-Media.) Horrendous beeping noise that changes but does not disappear depending on sampling rate. Not continuous, so can’t be filtered out. It’s possible this is a faulty unit.

OK, nothing satisfying there. But the latest generation of Macs include an external microphone of sorts. If you plug in a set of iPhone headphones, the microphone is recognised and works. It’s the standard “extra pin on the minijack” cable that video cameras have used for years to get 3 signals (composite video, left audio, right audio) so theoretically it could work. (Mac OS X Hints for more info.)

I tried a combination of cables and adapters, but no luck recognising my SVM through this route. Probably just something simple (rather than detecting a security chip) but it wouldn’t show up. But… what does the microphone in the iPhone headphones sound like?

5. The iPhone headphones, plugged directly into the Mac Pro. Not bad at all. Better than the Singstar mic. Not quite as good as the SVM but lower noise, because there’s built-in ambient noise cancellation. You can turn it off in Sound preferences, but you’re probably not going to do any better playing about in Soundtrack and it’s much more convenient. Unfortunately, pops and clicks are a problem. The SVM comes with a handy “dead kitten” (a small “dead cat”) that kills them and wind noise dead. Nearly there.

6. The iPhone headphones, plugged directly into the Mac Pro, with the SVM’s dead kitten around the mic capsule. Better. Certainly much better than you have any right to expect for a pin-sized input. Sounds not quite as good as the SVM under (elusive) perfect conditions.

Here’s a sample recording of this setup, with no additional noise reduction and with a small child running around in the background.

This begs the question — what’s it like directly into the iPhone, with Voice Memos? It’s not bad, but the internal microphone does a little better than the headphones. Better with the dead kitten than without, but there’s no noise reduction going on. Could be a good solution, but I’d prefer direct access to the recordings without having to sync. I can’t find an app that will let me do noise reduction and instant syncing back to the Mac.

Phew. Far too much info, but I needed to get it out of my head and hopefully it’ll be useful to someone. Give the iPhone headphones a go if you’re stuck, stay close to the mic, and keep your voice level constant.