Microphone Comparison : Line Audio CM3 ORTF “vs” Sennheiser MKH 8040 ORTF

I recently bought a second-hand pair of Line Audio CM3, mainly to use them as a second (rear) pair of mics in addition to my main Sennheiser rig  in Double ORTF setup). The CM3 is made in Sweden and is a relatively cheap/cardioid/condenser/pencil microphone. Please note that the CM3 is now discontinued and replaced by the similar CM4. Click here to learn more.

This article is a quick comparison/shootout of a pair of CM3 “against” a pair of 8040, both in ORTF configuration.

I recorded both pair of mics into a Sound Devices MixPre-6 at the same gain level to get a fair comparison, then I matched the loudness to the same level, other than that, no processing have been applied.

The raw and level-matched recordings are included below :

Keys : Frequency Response and Transients

Moving Shaker : Stereo Image and Frequency Response

Roomtone : Noise Floor and Frequency Response

nb : windows are open

the test setup

Here are the spectrograms if you wanna take a look at the frequency response and ultrasonic spectrum.

Keys :

Sennheiser MKH 8040 ( click to enlarge )
Line Audio CM3 ( click to enlarge )

Roomtone :

Sennheiser MKH 8040 : by design the noise is rejected in the ultrasonic range. ( click to enlarge )
Line Audio CM3 ( click to enlarge )
  • The Line Audio CM3 pair / cheap is a good addition to my toolkit. These mics should work fine alongside the 8040s in a surround setup. Plus they are very light and relatively small and good looking. (yeah that counts too)
  • The CM3 have a natural and flat frequency response which is good for ambiences recordings.
  • The CM3 are way less sensitive than the 8040, I measured approximately 10 to 12db lower output with the same gain on the recorder.
  • When level are matched in post, noise is less audible on the 8040 because of the noise rejection in the ultrasonic range (although this can be a problem when sounds are pitched down for design purposes. We’ll talk about this in another article)
  • Ultrasonic response is pretty good on the CM3.
  • To me the stereo image is better with the 8040 pair (Moving Shaker example).
  • 8040 are RF-biased, to my knowledge the CM3 are not, which can cause issues in damp conditons.

I’ll try to upload more examples in the future if some of you are interested.


2 replies
  1. Jerry
    Jerry says:

    IMHO, the 8040’s are just a little bit nicer. They sound slightly fuller, have a better transient response and tighter imaging. The CM3’s have a slight dip in center imaging, though they are wide cardioids. Positioning could easily make up the difference.

    I don’t have 8040’s but do have CM3s. Your CM3 recordings have the similar tone that I experience with mine. One thing with CM3’s is that they don’t handle wind very weil, even shielded. However, I like them and recommend them frequently (well the CM4’s now). Thx for posting. Also you have some nice SFX.

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