Topic: Zoom’s 32-bit float m/s - Instamic Pro Plus C

[datbrad]

I got the mono pair because the SNR specification is stated to be 72db, and the stereo version is 67db. I exchanged emails with the founder before choosing which one to buy. He said the added MEMS on the sides add noise but make it able to do a pseudo m/s recording. If my need was for video camera mounting I would definitely want the stereo version.

[mepaca]

Interesting, thanks.

[rastasean]

Thanks for sharing...kind of...now I'm thinking about ordering one. 

Zoom/Samuel FINALLY recorded with the device their selling!! That said, when he was outside, it didn't sound all the clear for his dialog; in the car was a little better.

I like the quotes from the pro sound guys, but I don't see any videos/recordings of their work on the product page. There is the guy on the water, though.

[Ozpeter]

Zoom have stated in the past that their devices are single ADC across the range, unless they specifically claim dual ADC.  In this case there's no dual ADC claim.  However, it seems to be the case that single ADC devices marketed with claims that match dual ADCs are the norm now. 

How they get stereo separation using multiple Omni mics in a tiny space puzzles me.  Something clever going on there.

In due course it will be interesting to see / hear comparisons with the Zoom Instamic vs cheaper and, in essence, smaller devices such as the Lark A1, of which I am a fan.  With that, in essence it's invisible, when worn inside a baseball cap and recorded on the phone.  The Instamic specs are better but which will be preferred is perhaps another matter.

Wind muffs would presumably be required for outside use.

[datbrad]

While these can be used as "wireless" mics transmitting to phone or camera via bluetooth like many others, it's the internal recording without auto-splits that makes Instamic unique. The "stereo" functionality of that version is achieved by adding a MEMS mic on each side in addition to the 4 MEMS array at the front, which permits mid/side recording. The separation isn't enough for time delay stereo, but the baffle effect is enough for intensity stereo. That being said, I opted for two of the mono versions because of the better SNR performance of that model.

More details about the recordings I posted; for the La Lom the Instamics were mounted on the ends of a 14cm crossbar with the furry windscreens, and the stand at 7.5'. For The Head and the Heart, each Instamic had the little spandex covers on them, and then dropped into the side pockets of a runners cap. It was fully soaked within a few min of the start of the show and remained drenched from there on.

These things aren't perfect. Sometimes there are interference issues in big crowds when initially pairing them to the phone app that can be irritating, but that's the magic of these. Once you get them synced to timecode and rolling, it doesn't matter if the connection breaks between them and the phone. They will run exactly as they were set at the start until they are re-paired to the app, or manually stopped with the button on the body.

[Niels]

This looks very interesting!
Some, for me, relevant questions I haven't found answered yet:
Are the internal batteries user replaceable?
Is the "soft-touch" finish the same as the awful rubber-like coating that turns into sticky goo after a few years?
Can they be feed with USB power while recording?
Can TC be jam-synced with Zoom's own products (not only Atomos and Tenacle Sync E as specified)?

[datbrad]

This looks very interesting!
Some, for me, relevant questions I haven't found answered yet:
Are the internal batteries user replaceable?
Is the "soft-touch" finish the same as the awful rubber-like coating that turns into sticky goo after a few years?
Can they be feed with USB power while recording?
Can TC be jam-synced with Zoom's own products (not only Atomos and Tenacle Sync E as specified)?

1. No, unfortunately just like Airpods and Fitbits, these have non-user replaceable batteries.
2. No, it is a flat finish of some kind, but it's not rubbery like the coating you are thinking of.
3. I have not tested that specifically, but I think it can. The stated 4.5 hour run time has proven true so I can't imagine needing to ever do that.
4. Mine are the pre-Zoom product but I would expect them to release a firmware update to make these compatible with their timecode system as well now that they own the product.

[Niels]

Thanks batbrad!

[mepaca]

Zoom have stated in the past that their devices are single ADC across the range, unless they specifically claim dual ADC.  In this case there's no dual ADC claim.  However, it seems to be the case that single ADC devices marketed with claims that match dual ADCs are the norm now. 




On the site it does say that it has dual a/d converters.

"Instamic’s dual A/D converters with 32-bit float recording capture every detail, from whispers to roars and everything in between, without clipping or distortion."

[Ozpeter]

Zoom have stated in the past that their devices are single ADC across the range, unless they specifically claim dual ADC.  In this case there's no dual ADC claim.  However, it seems to be the case that single ADC devices marketed with claims that match dual ADCs are the norm now. 




On the site it does say that it has dual a/d converters.

"Instamic’s dual A/D converters with 32-bit float recording capture every detail, from whispers to roars and everything in between, without clipping or distortion."

Thanks.  Either I didn't spot that, or they read this thread.... probably the former!

[Gutbucket]

I got the mono pair because the SNR specification is stated to be 72db, and the stereo version is 67db. I exchanged emails with the founder before choosing which one to buy. He said the added MEMS on the sides add noise but make it able to do a pseudo m/s recording. If my need was for video camera mounting I would definitely want the stereo version.

Not sure but the stereo unit which costs just a few dollars more might allow for either mono and stereo use.  If capable of operating in single-channel mono mode as well as in stereo, SNR should be identical to the mono version (72dB) when recording in mono mode.  SNR for the mono channel on its own presumably is improved via the use of the four MEMS wired in parallel on the front face of the unit. 

Either way, four MEMS arranged in a line and wired in parallel will produce a narrowing polar pattern at high frequencies in the same way that a larger diaphragm diameter does in an omni. So how you point these things may matter somewhat.  Best extended high frequency response should occur for wavefront arrival parallel to the line, so best to position it on-axis with the four MEMS pointed toward the sound source.

The tininess of MEMS elements usually translates to a high noise-floor. I imagine the four MEMS mic elements of the primary Mid channel are run in parallel to achieve better noise performance.  Not sure what that means for Side channel performance, as the two MEMS wired in reverse polarity to produce the fig-8 Side pattern will only provide for the equivalent noise performance of a single MEMS element.

Not sure how the stereo version might be generating stereo output.  My earlier post quoted above assumes Mid/Side processing, with the Side channel being generated via the two MEMS on either side of the unit.  Alternately it could be using the array of 6 MEMS to do some rudimentary beamforming.  In that case the MEMS would not be wired directly in parallel, but instead phase manipulations would be used to produce two separate "reception beams" angled somewhat to the left and right of the line, producing some form of X/Y. Probably pretty messy polars, but who cares if it sounds decent.. as long as it can also operate in mono mode without compromising SNR

[datbrad]

I got the mono pair because the SNR specification is stated to be 72db, and the stereo version is 67db. I exchanged emails with the founder before choosing which one to buy. He said the added MEMS on the sides add noise but make it able to do a pseudo m/s recording. If my need was for video camera mounting I would definitely want the stereo version.

Not sure but the stereo unit which costs just a few dollars more might allow for either mono and stereo use.  If capable of operating in single-channel mono mode as well as in stereo, SNR should be identical to the mono version (72dB) when recording in mono mode.  SNR for the mono channel on its own presumably is improved via the use of the four MEMS wired in parallel on the front face of the unit. 

Either way, four MEMS arranged in a line and wired in parallel will produce a narrowing polar pattern at high frequencies in the same way that a larger diaphragm diameter does in an omni. So how you point these things may matter somewhat.  Best extended high frequency response should occur for wavefront arrival parallel to the line, so best to position it on-axis with the four MEMS pointed toward the sound source.

The tininess of MEMS elements usually translates to a high noise-floor. I imagine the four MEMS mic elements of the primary Mid channel are run in parallel to achieve better noise performance.  Not sure what that means for Side channel performance, as the two MEMS wired in reverse polarity to produce the fig-8 Side pattern will only provide for the equivalent noise performance of a single MEMS element.

Not sure how the stereo version might be generating stereo output.  My earlier post quoted above assumes Mid/Side processing, with the Side channel being generated via the two MEMS on either side of the unit.  Alternately it could be using the array of 6 MEMS to do some rudimentary beamforming.  In that case the MEMS would not be wired directly in parallel, but instead phase manipulations would be used to produce two separate "reception beams" angled somewhat to the left and right of the line, producing some form of X/Y. Probably pretty messy polars, but who cares if it sounds decent.. as long as it can also operate in mono mode without compromising SNR

I exchanged emails for a couple of weeks with Michele Baggio, the developer and founder of Instamic, before making a purchase. I went back and re-read some of them and he confirmed that when the stereo version is in M/S mode, all 6 MEMS are working, and in mono mode it's identical to the straight mono version. Only when using the stereo mode does the SNR drop from 72 to 67. I considered buying one of each for versatility, but ended up going with a pair of monos.

[Gutbucket]

Thanks for the confirm on that and your insight into the practical use of these things.

There's promise here for sure.  I need to give your LA LOM and Head and the Heart recordings a listen.  Thanks for posting those.

[Craig T]

How do you orient these to the sound source / what is "on axis"?

[goodcooker]

what is "on axis"?

Sound arriving from the direction that the center of the diaphragm is "pointed" at.