The Audix TM-1 is a pre-polarized condenser measurement microphone. With a fixed omni-directional polar pattern and flat frequency response from 20 Hz-25,000 Hz the TM-1 is a designed for testing applications. Its nickel-plated brass body is sturdy, and looks like it could take a beating and still come back for more. It's got a heavy-duty clip to stay in place. There is also a windscreen that screws onto the mic that is a nice design.
Perhaps you know the drill. Put your test mic on a stand near the mix position. Feed your test mic into SMAART or another frequency-analyzer program. Run pink-noise through your system. The read-out tells you what is going on with your system and in your room. Interpret this data and make the appropriate changes to equalizers, crossovers, and amp settings.
But how do you test a test mic? These are the mics that you buy because they are supposed to be accurate. They are supposed to do what they say they do. You tune your room to these. All of your choices come through what these mics tell you about your room and the acoustic you are dealing with. We just assume they do what they are designed to.
I used the TM-1 a handful of times tuning different rooms over a weeks worth of time. I have previously used a mic from another manufacture and never had any complaints. My old mic seemed to be accurate and do the job quite nicely. It was pretty cheap too, which wasn't a bad thing either. However I left that mic at home and took the TM-1 out to see how it would do.
How did I notice a change for better or worse? Well, after doing the “scientific” tune, there are always some changes that happen once the bands start playing. Different frequencies might jump out that are being affected by the characteristic of the room. The stage volume of amps and instruments change things as well. If you are mixing monitors with wedges then that has an effect as well. After using the TM-1, I noticed these [after-tuning] changes were not as dramatic, particularly in the top end. At the time I was not sure what to attribute this too.
Better build-quality maybe? Better components? More accuracy?
Having used the TM-1 on the road, I took it back to my studio to A/B it with my “standard” test mic. I was interested to find out that there were some differences in how the mics were picking up signal. I found there was about a 5 dB difference between the two mics around 10 kHz. Another 2 dB difference around 6 kHz. So the two mics were picking things up a bit different.
The spec sheet for the Audix TM-1 says it has a frequency response of 20 Hz to 25,000 Hz (+/- 2 dB). Specs for the other “standard” mic were not as detailed. The only documentation I could find states that the mic has “flat response from 20 Hz to 20,000 Hz”. That could mean anywhere up to +/- 0 dB to 10 dB. But without a professional anechoic chamber, my studio comparison is not conclusive. Yet a comparison of the manufacturer's specs leads one to believe that the variability could be with my “standard” mic, since the +/- variability of its frequency response is not stated.
Then I began wondering if this difference is all that significant in an end result. I had trusted my “standard” mic for many years. Yet, as with all audio tools, you need understand what is happening and let that information guide your decisions. Just knowing this now allows me to approach things a bit different with my old mic.
In reading through the Audix manual I discovered another great application for the TM-1: as an ambient mic for adding to IEM [in-ear monitor] mixes. The TM-1 provides a very accurate room picture which provides players using IEM's with a greater sense of being in the performance space.
Another great application of this mic would be to use a pair of these on a record feed.
After spending time with the Audix TM-1, I found it to be a solid, reliable choice for test and measurement purposes—and other uses—and costs just $299.
