First, let me thank Frances K, a reader of our blog, for bringing the CM-1000 boundary microphone to my attention.
There’s a dearth of options when looking for a 3.5mm boundary microphone with daisy chain capabilities.
Let’s have a quick recap why each of these features are important for recording high quality focus group discussions.
3.5mm refers to the output jack of the microphone. To record sound from a microphone you need to attach it to a recorder. And there are numerous ways you can achieve this.
Popular ways to connect boundary microphones to recording devices are USB, XLR, wireless, and 3.5mm.
3.5mm boundary microphones are ideal because you can connect them to a digital voice recorder, which means that they are small and portable. With USB, XLR, and wireless boundary microphone, you will need a relatively large recording device to power (USB, XLR) and record the output audio. I’d recommend these other types of boundary microphones if you intend to install permanent recording capabilities; in a meeting room or conference facility: they are not ideal for focus group discussions done for academic research – the main subject of this blog.
Boundary microphones are designed to have a wide area of coverage while recording very little background noise. That makes them ideal for recording a large group of subjects.
Daisy chain, now this is the ability to connect microphones (in parallel or series), that you end up with a single audio output. Most manufactures recommend you connect up to 6 microphones but, from my testing, there is no reason you cannot connect as many as you want, as long as you are able to provide enough plug-in-power to power them.
Without daisy chain capable microphones, you end up with multiple recordings of the same focus group (for instance from different recorders) and you’ll need to merge them into one recording in post. Merging the recordings is not a difficult task, it just takes time, the right software, and a little know how.
So, for these reasons, researchers looking for flexibility and portability, 3.5mm boundary microphones are your best bet for recording high quality focus group discussions.
However, you don’t have lots of choice when looking for boundary microphones. Philips make a good 3.5mm boundary microphone, but each costs $200! Olympus have an equally good boundary microphone that I have extensively reviewed. And now the CM-1000.
The CM-1000 is manufactured by VEC Electronics, which focuses on “developing a line of high quality, well priced dictation, transcription and audio accessories.” At $40 on Amazon, the CM-1000 is comparatively well priced. But is the CM-1000 a high quality boundary microphone?
In each box, you get the SoundTech CM-1000 and a carrying pouch. Mine came with a blue one. The pouch is large for the microphone, you can easily fit 2, but will protect the microphone from dust and scratches.
The microphone is small, has a UFO shape that’s 3 inches (about 8cm) across. The top of the microphone is made from a strong metal mesh and the bottom has a non-skid rubber surface, which bring me to my first criticism of the CM-1000, the smell.
The rubber bottom is glued onto the plastic frame using a cheap glue that has unpleasant odor that hits you hard when you unbox the CM-1000. With continued used, the odor has dissipated, but it’s something to be aware of. You may want to unbox and air the microphones out for a couple of days before use.
It also comes with 8 feet (2.5 meters) cable terminated with a 3.5mm TRS (stereo) plug/jack. The cord is attached to a plastic container whose sole purpose is to house the microphone serial number and a “warranty is void if seal is broken” tag.
First that kind of messaging is illegal and frowned on by the FDA. But also that plastic tag is really hard to remove. You run a real risk of slicing the cord if you try to pry it off with a knife. I was able to cut off the top cover of the tag with a sharp blade, but it’s easier to wrap it up in the cord and hide it using the Velcro (hook and loop) strap that also comes attached to the microphone cord.
I opened up the microphone by removing the rubber bottom, and then prying the metal mesh. The microphone is suspended from the plastic frame, which is great for reducing contact sounds (table tapping etc). Inside the microphone is also a metal plate that adds weight to microphone.
Overall, I’d say the build of the CM-1000 comes across as cheap, and poorly designed. There is no good way to manage the cable. Instead of a heavier, more robust body, the manufacture choose to add a metal plate to weigh down the microphone. The use of cheap adhesive to glue on the rubber bottom. Add to that the illegal warranty tag, and this is product that has a very “made in china” look and feel.
The CM-1000 requires plug-in power to operate. So you do need to connect it to a recording device that outputs plug-in power.
Most digital voice recorders with mic-in do output plug-in power. But computers, laptops, and phones don’t; this microphone does not work when you connect it to these devices.
Once you connect it to a digital recorder, you’ll be surprised at how sensitive it is. I’d say that the CM-1000 is the most sensitive microphone that I own (and I own a lot of them), especially at lower frequencies.
As this is a “hot mic,” you really have to control the gain of the output from the CM-1000 so as to ensure you don’t have distortion in your recording.
But this is countered by the significant drop in the sound volume from the CM-1000 when you daisy chain them. If you daisy chain 4 of them, you get a 9dB drop in sound output.
I’ve yet to figure out why this happens (I’ll keep at it, and if you have any suggestion let me know in the comment sections below), and it occurs with my other boundary microphones. My initial thought was the voice recorder was not providing enough voltage to the microphones. But had a chat with an electrical engineer and we did some math, realized that these microphones draw very little power from the recorder – because they have very high resistance.
Other than that, I was surprised at how similar the frequency response of the CM-1000 is to other microphones I own. It has a flat frequency response, though it does tamper off at high frequencies. And the recording was clear, natural sounding and the microphone suppressed background noise and had good coverage.
I am conflicted about the CM-1000. It records good quality sound and it’s relatively cheap (it’s the cheapest daisy chain boundary microphone I know of). But to achieve this, the manufacture (VEC) cut lots of corners in the build quality, which does not bode well for the durability and usability of the CM-1000.
Ultimately, I prioritize function over form. So yes, I recommend the CM-1000 to researchers who are planning to record focus group discussions and as a cheaper alternative to the Olympus ME-33.
That’s it for this post. Hope you enjoyed it. If you have any questions, please post them in the comment section below and I’ll try to answer them to the best of my capabilities. Have a great day and happy recording.