I think there is indeed some confusion in this discussion between the signal-to-noise ratio of these mics, and dynamic range.

The first is conventionally related to 1Pa/94dB SPL, and one then needs to add in a Max SPL figure to get the dynamic range.

We need both bits of information to understand the practicality of any mic.

A noise floor of 24dBA (related to 1Pa) is about par for a small personal electret mic. A dynamic range of >115dB is what one would wish for in decent professional mics - that would be a noise floor of 15dBA and a max SPL of >130dB (with a distortion figure of 3 or 5%).

Chris Woolf (ex editor of Microphone Data)


On 18/08/2018 08:41, Bo-Erik Sandholm wrote:
According to the document linked to below that relates self noise values to
real world applications 110 SNR cannot be related to the commonly used
reference sound level.
110 dBA SNR would be 16 dB below absolute quiet.

If the value 70dBA that I found for the infineon dual membrane MEMS mic is
related to 1 Pascal, then it's self noise is around 24 dB which is not
strictly studio quality.
But not really horrible.
If it is related to max 10% distortion which is at 135 dBA thats not a
realistic comparison value as the result is a self noise of 65 dBA.

That would be a noise source not a microphone :-) !

So a bit of apples and oranges comparison is going on 😎


http://www.neumann.com/homestudio/en/what-is-self-noise-or-equivalent-noise-level

SIGNAL-TO-NOISE RATIO
Another way to document the noise performance is to specify the
signal-to-noise ratio. But relative to what signal? The reference sound
pressure level for noise measurements is 94 dB (which equals a sound
pressure of 1 pascal). So you can simply calculate:

Signal-to-noise (db-A) = 94 dB – self-noise (dB-A)



The actual signal-to-noise ratio in use, of course, depends on the sound
pressure level of your sound source.


Bo-Erik

On Sat, 18 Aug 2018 01:37 Jack Reynolds, <jackreynolds...@gmail.com> wrote:

Are you sure the Ambeo has 110dB SNR?

Sent from my iPhone

On 17 Aug 2018, at 23:56, Paul Hodges <pwh-surro...@cassland.org> wrote:

--On 17 August 2018 14:55 -0700 Ralph Jones <rjonesth...@comcast.net>
wrote:

Some folks posting here have seemed to suggest that this level of
noise might possibly be acceptable.
Well, firstly we don't know the actual specification of the devices
used by Zylia.  And secondly, using an array of nineteen to generate an
output gives the possibility of significant improvement, because the
sound source signals are correlated and the noise is uncorrelated.

How this holds up in practice at higher orders and higher frequencies I
will attempt to judge when I get my hands on the ZM-1 rather than just
predicting failure in advance (which is not consistent with the reviews
I've seen heard and read).

Paul

--
Paul Hodges

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