Tetra Mic from Core Sound

[Sabyasachi Patra]

Has anyone used this tetra mic from Core sound? Core Sound — TetraMic

How good or bad is the quality? Look forward to hear your views.

[Richard Crowley]

There is an extensive discussion about the Tetra Mic (including participation from Len Moskowitz from Core Sound) over on GearSlutz

Tetramic? - Gearslutz.com

[Sabyasachi Patra]

Thanks Richard!

That link has got tons of information.

[Gary Nattrass]

Basically a copy of the design of the (calrec) soundfield mic: SoundField: The Company

So it should give similar results but at a lot lower cost !

[John Willett]

Originally Posted by Gary Nattrass

Basically a copy of the design of the (calrec) soundfield mic: SoundField: The Company

So it should give similar results but at a lot lower cost !

But the Soundfield uses true condenser capsules and the Tetra uses unbalanced electrets.

And there is the new "Brahma" coming soon, which will be even cheaper - looks interesting.

[Richard Crowley]

All condenser mic capsules (externally charged AND electret) are "unbalanced" by nature.
And some of the highest-regarded microphones on the planet are electret (e.g. DPA)

Now it is quite possible (probable?) that the Tetra capsules and circuitry are of lower quality than the ones
Calrec uses, but that is likely the case with most any kind of product that is available in several price ranges.

[John Willett]

Originally Posted by Richard Crowley

All condenser mic capsules (externally charged AND electret) are "unbalanced" by nature.
And some of the highest-regarded microphones on the planet are electret (e.g. DPA)

Now it is quite possible (probable?) that the Tetra capsules and circuitry are of lower quality than the ones
Calrec uses, but that is likely the case with most any kind of product that is available in several price ranges.

Yes and no.

An RF condenser mic. *is* balanced by nature.

Although an AF condenser is an unbalanced capsule, it is balanced inside the housing of the microphone and exits the microphone as a fully balanced signal.

The Tetramike exits the microphone on an unbalanced cable and is, as far as I am aware, only gets balanced at the XLRs at the end of the cable.

Oh - Calrec have had no involvement with the Soundfield microphone for decades - they sold it to AMS who then sold it to Ken Giles (Soundfield) who retired last year and sold the company to TSL in Marlow.

The Soundfield capsules are OEM supplied by MBHO in Germany, who have a quality equivalent to that of Schoeps.

[Rick Reineke]

"T]he Tetramike exits the microphone on an unbalanced cable and is, as far as I am aware, only gets balanced at the XLRs at the end of the cable."
This is the case for most lavaliere mics as well.

[John Willett]

Originally Posted by Rick Reineke

"The Tetramike exits the microphone on an unbalanced cable and is, as far as I am aware, only gets balanced at the XLRs at the end of the cable."

This is the case for most lavaliere mics as well.

Yes - but most professional microphones are fully balanced from the output of the microphone.

It's only consumer microphones and electret tie microphones & headmics that run unbalanced down a cable.

Running unbalanced down a cable increases the risk of RF interference, especially when the cable length gets close to the frequency of the RF interference.

[Rick Reineke]

That's what I was stating. "electret tie microphones (aka, lavalieres) & headmics"
Furthermore, most lavs that have 3 wires, the 'third' wire is for bias current (power).. from a transmitter, in-line battery or XLR Phantom Power adapter.

[Richard Crowley]

Originally Posted by John Willett

Yes - but most professional microphones are fully balanced from the output of the microphone.

Note that "the output of the microphone" may not be the microphone head itself.

And some "professional microphones" do not have true differential-balanced output, but are actually single-ended and are just "impedance balanced" with a 5-cent resistor.

It's only consumer microphones and electret tie microphones & headmics that run unbalanced down a cable.

Many professional condenser microphones run unbalanced audio between the microphone head and the power supply box where the output transformer is located. A run of unbalanced audio is not an indication of "cheap" or "low-end". The unbalanced audio is typically cathode-follower and relatively low impedance. Modern electret capsules have impedance conversion circuits inside the capsule which is a modern equivalent of that classic circuit design.

Running unbalanced down a cable increases the risk of RF interference, especially when the cable length gets close to the frequency of the RF interference.

Not just RF interference. In fact, probably even MORE susceptible to in-band interference.RF interference can be easily filtered, but in-band cannot.