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Spat.hoa.em32 microphone positions

Spat
#1

Hello,

I’m currently upgrading from Max 6 to Max 8 and from spat4 to spat5.

I am using the mh acoustics Eigenmike to record 3D soundfields and would like to use spat5 tools to encode our recordings to HOA. With max 6 and spat4 I used the object spat.em32 and it worked just fine, however this object doesn’t give access to the eigenmike microphone positions but in spat.eigenencode (spat4) we noticed an inversion of position between microphones 13 and 14 (compared to the positions provided by mh acoustics eigenmike datasheet).

Now, I am using spat5.hoa.em32 object from spat5 but I would like to make sure that the 32 microphones positions of the eigenmike in spat5 match with the ones provided by mh acoustics. I was not able to find informations on spat doc about the microphones positions. I especially would like to know if this inversion between mic 13 and 14 has been corrected or if there is any possibility to enter our own coordinates for each microphone ?

Thanks in advance.

Simon

#2

Hello Simon,

spat5.hoa.em32~ uses the microphone positions as provided by mh acoustics eigenmike datasheet.
The user has no possibility to enter his own coordinates.

The mic 13/14 inversion in some previous version was intentional, as it corresponded to one specific microphone where these two transducers were actually inverted (a wiring issue inside the eigenmike).
There is no such inversion in newer (spat5) objects.

Best,
T.

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#3

Thanks a lot for your reply,

When you say “it corresponded to one specific microphone where these two transducers were inverted” do you mean that this inversion was specific to the microphone you used and I should not take it into account ? or was it specific to one series of eigenmikes (the eigenmike I use is from 2015). Anyway, I will probably contact mh acoustics to make sure that our eigenmike doesn’t have the same inversion problem.

Thanks again !
Best regards,

Simon

#4

I believe this only affected one given specimen (not a series of eigenmikes).
Anyway, it’s easy to verify the “correctness” of your eigenmike : gently scratch each microphone cell independently, and see it that matches the positions given in the datasheet.

Best,
T.

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