[AUDITORY] Anechoic room floor grate construction question

["Brian FG Katz (SU)" <brian.katz@xxxxxxxxxxxxxxxxxxxxxx>]

Dear community, 

This is a message for those of you that have an anechoic room. 

We have an relatively new anechoic room. The floor is a series of metal grate panels (basically these https://sc01.alicdn.com/kf/HTB14iKDsyAKL1JjSZFoq6ygCFXaI.jpg) that sit on support beams, able to support the weight of say a grand piano... A suspended wire mesh solution is not suitable for our needs.

We are currently having problems with the floor grate panels in our anechoic room, being that they are very "ringy", easily excited acoustically, i.e. a hand clap makes an audible ring with a clear reverberation time in a narrow frequency band. 

We have tried multiple means for isolating them (neoprene pads) with no effect. Damping them needs so much material and weight that they are no longer transparent. So, I am interested to know what type of rigid grate solutions any of you may have that you are happy with. 

I hope that bouncing this idea of this large list will get me are good range of solutions that we can then consider in order to replace what we have, without having to go through a large battery of samples and testing. 

As images would be helpful, please email me directly, as I think the list filters out attachments. 

Thank you in advance,
-Brian
--
Brian FG Katz, Ph.D, HDR
Research Director, CNRS
Groupe Lutheries - Acoustique - Musique Sorbonne Université, CNRS, UMR 7190, Institut Jean Le Rond ∂'Alembert
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