Hi everyone, Regarding the question of which mems the ZM-1 uses, here is some detailed info I just found: https://www.infineon.com/cms/en/about-infineon/press/market-news/2018/INFPMM201808-078.html
Best, Florian www.grond.at On Sat, Aug 18, 2018 at 12:00 PM <sursound-requ...@music.vt.edu> wrote: > Send Sursound mailing list submissions to > sursound@music.vt.edu > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.music.vt.edu/mailman/listinfo/sursound > or, via email, send a message with subject or body 'help' to > sursound-requ...@music.vt.edu > > You can reach the person managing the list at > sursound-ow...@music.vt.edu > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Sursound digest..." > > > WHEN REPLYING EDIT THE SUBJECT LINE > > ALSO EDIT THE MESSAGE BODY > > You are receiving the digest so when replying, please remember to edit > your Subject line to that of the original message you are replying to, so > it is more specific than "Re: Contents of Sursound-list digest…" the > subject should match the post you are replying to. > > Also, please EDIT the quoted post so that it is not the entire digest, but > just the post you are replying to - this will keep the archive useful and > not polluted with extraneous posts. > > This is the responsibility of digest subscribers. the community and list > subscribers care about the integrity of the threads and archives so this is > important. > > Today's Topics: > > 1. MEMS SNR Specifications (Ralph Jones) > 2. Re: MEMS SNR Specifications (Paul Hodges) > 3. Re: MEMS SNR Specifications (Jack Reynolds) > 4. Re: MEMS SNR Specifications (Bo-Erik Sandholm) > 5. Re: MEMS SNR Specifications (Chris Woolf) > 6. Re: MEMS SNR Specifications (Fons Adriaensen) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 17 Aug 2018 14:55:36 -0700 > From: Ralph Jones <rjonesth...@comcast.net> > To: sursound@music.vt.edu > Subject: [Sursound] MEMS SNR Specifications > Message-ID: <3ef51b54-d429-4def-8add-ccf0a8943...@comcast.net> > Content-Type: text/plain; charset=utf-8 > > There?s been some interesting discussion here about > Micro-ElectroMechanical Systems (MEMS) microphones for ambisonic mic > arrays. These devices seem to offer some compelling qualities (particularly > small size and low cost) but their signal-to-noise spec is 65 dBA. Some > folks posting here have seemed to suggest that this level of noise might > possibly be acceptable. > > IMHO, based on decades of experience, a microphone with a signal-to-noise > ratio of 65 dBA is useless for professional recording. That's in the SNR > range typical of consumer cassette tape machines or analog AM radio. > > For comparison, consider that professional large-diaphragm condenser mics > achieve 120-130 dB SNR. The Sennheiser Ambeo has an SNR of about 110 dB. > Portable digital audio recorders and popular audio interfaces make about > 100 dB, and Red Book CDs 98 dB. Even vinyl records are about 6 dB quieter > than MEMS mic elements. > > Put a MEMS mic at the input of a digital recorder and you?re wasting 35 dB > of dynamic range (not to mention the case of using several of them in an > ambisonic array). That?s huge. A symphony orchestra playing at mezzoforte > or louder may mask the noise if the mic is reasonably close to the stage, > but forget trying to record softer passages. Recordists trying to capture > natural ambiences will be sorely disappointed; a lot of what they?re trying > to record will simply disappear into the noise floor. You might get away > with using it for non-critical functions like background crowd noise for > telecasts of sporting events, but that?s about it. > > MEMS mics appear to me to have been developed for applications that > require very small size, physical ruggedness, reasonable frequency response > and low cost, but can tolerate a high noise floor. There are lots of such > use cases, but professional audio is not one of them. If we wish to advance > the art of ambisonic recording and reproduction, we cannot compromise basic > performance specifications for the sake of a trendy idea. > > Ralph Jones > > ------------------------------ > > Message: 2 > Date: Fri, 17 Aug 2018 23:56:21 +0100 > From: Paul Hodges <pwh-surro...@cassland.org> > To: Surround Sound discussion group <sursound@music.vt.edu> > Subject: Re: [Sursound] MEMS SNR Specifications > Message-ID: <959BC7A058AAE6865F337CAC@[192.168.1.74]> > Content-Type: text/plain; charset=us-ascii > > --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 > > > > ------------------------------ > > Message: 3 > Date: Sat, 18 Aug 2018 00:37:22 +0100 > From: Jack Reynolds <jackreynolds...@gmail.com> > To: Surround Sound discussion group <sursound@music.vt.edu> > Subject: Re: [Sursound] MEMS SNR Specifications > Message-ID: <918d363c-eb4c-42bc-81d7-97dd2854c...@gmail.com> > Content-Type: text/plain; charset=us-ascii > > 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 > > > > _______________________________________________ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > > > ------------------------------ > > Message: 4 > Date: Sat, 18 Aug 2018 09:41:13 +0200 > From: Bo-Erik Sandholm <bosses...@gmail.com> > To: sursound <sursound@music.vt.edu> > Subject: Re: [Sursound] MEMS SNR Specifications > Message-ID: > <CAEAiL24g=oFicUeY4cjyxxGebA7YPnP3ZHSmRN9Hp3gFoW+== > w...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > 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 > > > > > > _______________________________________________ > > > Sursound mailing list > > > Sursound@music.vt.edu > > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > here, > > edit account or options, view archives and so on. > > _______________________________________________ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > > edit account or options, view archives and so on. > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20180818/40e5ff31/attachment.html > > > > ------------------------------ > > Message: 5 > Date: Sat, 18 Aug 2018 09:56:57 +0100 > From: Chris Woolf <ch...@chriswoolf.co.uk> > To: sursound@music.vt.edu > Subject: Re: [Sursound] MEMS SNR Specifications > Message-ID: <f5b56a54-8bbe-5c8e-8066-4d2364c4f...@chriswoolf.co.uk> > Content-Type: text/plain; charset=utf-8; format=flowed > > 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 > >>> > >>> _______________________________________________ > >>> Sursound mailing list > >>> Sursound@music.vt.edu > >>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > here, > >> edit account or options, view archives and so on. > >> _______________________________________________ > >> Sursound mailing list > >> Sursound@music.vt.edu > >> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > >> edit account or options, view archives and so on. > >> > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20180818/40e5ff31/attachment.html > > > > _______________________________________________ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > > > ------------------------------ > > Message: 6 > Date: Sat, 18 Aug 2018 11:52:59 +0200 > From: Fons Adriaensen <f...@linuxaudio.org> > To: Surround Sound discussion group <sursound@music.vt.edu> > Subject: Re: [Sursound] MEMS SNR Specifications > Message-ID: > <20180818095259.tn2qzqp4f6we5...@mail1.linuxaudio.cyso.net> > Content-Type: text/plain; charset=us-ascii > > On Sat, Aug 18, 2018 at 09:41:13AM +0200, 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. > > Maybe possible with an unexistium membrane and left twisting electrons ... > :-) > > > 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. > > It's the self noise figure which matters in the end. It simply means > that if you record a sound with an SPL of say 60 dB (at the mic), the > S/N ratio would be 60 - 24 = 36 dB. Using a 'pro' mic with a self > noise of 10 dB the S/N ratio would be 50 dB. In both cases assuming > the preamp doesn't add a significant amount of noise. > > Noise of 'virtual mics' (or ambisonice components) synthesised from > multiple capsules is not so simple. > > If S_i is the signal from the i-th capsule then the beam signal is > of the form > > S_beam = sum (a_i * S_i) i = 1..B > > where the a_i are complex gains depending of frequency. Now if the > a_i are scaled such that the on-axis sensitivity of the beam is the > same as that for a single capsule, then the noise power in the beam > signal is the sum of the squares of the a_i: > > N_beam = sum (a_i ^ 2) > > For an 'omni' pattern this typically results in a significant > improvement, up to 3dB * log2 (N) in the best case (ommi > capsules at low and medium frequencies). > > For directive patterns, almost anything can happen depending > on if the capsules are omni or directional, if they are in > free space or on a solid body, and the order of the pattern. > The actual noise will not be white which means that traditional > noise figures (e.g. A-weighted) become more or less useless. > > Typically you may see some improvement over the single capsule > noise level in some small frequency region, and more noise > in other frequency bands. > > For some examples, get hold of the original Eigenmic manual > which shows noise performance as a function of frequency > for each of the available patterns. That's the only example > I know of a manufacturer documenting this, most (including > Zylia) will hide the truth in lots of blabla. > > Ciao, > > -- > FA > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound > > WHEN REPLYING EDIT THE SUBJECT LINE > > ALSO EDIT THE MESSAGE BODY > > > ------------------------------ > > End of Sursound Digest, Vol 121, Issue 13 > ***************************************** > -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20180828/a34fb60b/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
