2 réponses
Hello,
None, only the fact of getting closer to the source (microphone on the teacher's table, if it doesn't move or clipped to his collar or positioned in front of a speaker could allow this feat).
At worst, you take an electret microphone and extend it with a mono extension (making sure not to stretch a trip hazard wire in the amphitheater), at best you get a transmitter receiver that the teacher would pin to his collar (not easy, but the only effective method apart from having a boom operator follow him step by step).
see:
https://forums.commentcamarche.net/forum/affich-35773925-dictaphone
https://forums.commentcamarche.net/forum/affich-33068924-une-camera-compatible-avec-un-micro-canon
https://forums.commentcamarche.net/forum/affich-32568618-choix-de-dictaphone-et-moyen-de-retranscription
https://forums.commentcamarche.net/forum/affich-33075956-enregistrenet-avec-bruit-de-fond
https://forums.commentcamarche.net/forum/affich-33079915-meilleur-microphone
https://forums.commentcamarche.net/forum/affich-37333253-micro-bonne-qualite
None, only the fact of getting closer to the source (microphone on the teacher's table, if it doesn't move or clipped to his collar or positioned in front of a speaker could allow this feat).
At worst, you take an electret microphone and extend it with a mono extension (making sure not to stretch a trip hazard wire in the amphitheater), at best you get a transmitter receiver that the teacher would pin to his collar (not easy, but the only effective method apart from having a boom operator follow him step by step).
see:
https://forums.commentcamarche.net/forum/affich-35773925-dictaphone
https://forums.commentcamarche.net/forum/affich-33068924-une-camera-compatible-avec-un-micro-canon
https://forums.commentcamarche.net/forum/affich-32568618-choix-de-dictaphone-et-moyen-de-retranscription
https://forums.commentcamarche.net/forum/affich-33075956-enregistrenet-avec-bruit-de-fond
https://forums.commentcamarche.net/forum/affich-33079915-meilleur-microphone
https://forums.commentcamarche.net/forum/affich-37333253-micro-bonne-qualite
Example https://www.amazon.fr/Tascam-Enregistreur-portable-microphone-directionnel/dp/B075V83JW8
.
Another example with a recorder featuring 5 mics
https://www.amazon.fr/H2n-Enregistreur-pistes-portable-Mid-Side/dp/B005CQ2ZY6/ref=pd_sbs_2/258-9138016-6286113?pd_rd_w=4B1Co&pf_rd_p=a8b99513-9ed9-4379-9ce7-04130b9ba223&pf_rd_r=98YTDB1Z26XSSZ19MPME&pd_rd_r=2972d3a1-a71b-44e1-bfec-a7a4bb39faff&pd_rd_wg=z6j4I&pd_rd_i=B005CQ2ZY6&psc=1
.
A comparative site for audio recorders
https://www.solfege.org/meilleur-enregistreur-audio/
.
https://www.amazon.fr/Zoom-H1n-IF-Enregistreur-Num%C3%A9rique/dp/B077QZPDM6?__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=zoom+h1n&qid=1629035700&sr=8-1&linkCode=sl1&tag=solfegeorg-21&linkId=60e6d62692e17a0719875740f94f4700&ref_=as_li_ss_tl
.
So, an audio recorder with a directional mic, or even with a shotgun mic, because with unidirectional or omnidirectional, the sound coverage will not be adequate unless we place the mic under the speaker's nose.
https://www.amazon.fr/s?k=micro+canon&__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&ref=nb_sb_noss_2
If one wants to be discreet, they need to turn to spying devices, but the quality will not be there.
Moreover, it is not prohibited to record or film classes at university for private use. However, it is forbidden to use them for public, commercial purposes, or to harm anyone.