Acoustic transparency of speaker grilles

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tallevan
Posts: 21
Joined: Sun Oct 20, 2019 12:15 pm
Location: London, England

Acoustic transparency of speaker grilles

#1 Post by tallevan » Wed Nov 06, 2019 10:51 am

My Omni 12 Tallboy is coming along nicely.

I like the idea of the expanded metal mesh that Bill suggests in his plans. No use spending silly money on grilles when you don't have to.

But here in Blighty, it's available only in large sheets. Also, the stuff we get here is rough as a badger's arse, and is a ittle more flexible than I like.

Needing only a small piece for the woofer grille (7x23), I purchased this. It's 2mm thick aluminium, with 10mm round holes on a 15mm pitch.

My question is, is this sufficiently acousticaly transparent?

I've been reading scholerly articles and swivel-eyed fanboy postings, and feel that it's fine, but given the size of the horn mouth we might be getting into the danger zone.

What do you reckon?
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Bruce Weldy
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Re: Acoustic transparency of speaker grilles

#2 Post by Bruce Weldy » Wed Nov 06, 2019 11:07 am

tallevan wrote:
Wed Nov 06, 2019 10:51 am


What do you reckon?
The key it the percentage of open area. Is that available for that screen?

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


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Bill Fitzmaurice
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Re: Acoustic transparency of speaker grilles

#3 Post by Bill Fitzmaurice » Wed Nov 06, 2019 11:49 am

Since you're only intending to use it over the woofer output I don't see a problem. As you go up in frequency the area between the holes becomes progressively larger with respect to the wavelengths being passed, which would probably be audible if it was over the tweeter output.

tallevan
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Joined: Sun Oct 20, 2019 12:15 pm
Location: London, England

Re: Acoustic transparency of speaker grilles

#4 Post by tallevan » Wed Nov 06, 2019 1:50 pm

Thanks for your replies. Much appreciated.

I calculate the transparency at 40.3% of the total area.
This is discounting the 3/4 inch of battens around the inside perimiter of the 7x23 inch port.

I'll go with that, but try with screen off/screen on to see if i hear any difference.

himhimself
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Re: Acoustic transparency of speaker grilles

#5 Post by himhimself » Wed Nov 06, 2019 4:39 pm

This is what I used on my OTop Jarrays. Steel, not aluminum. Percent open was less than what I would have liked, but the price was right, from Amazon at less than $20 for a sheet that let me cut our 4 grills. Painted black, it looks great and I can't notice any impact on the sound quality at all.
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2xT30 (20", 3012lf)
4xOtop Jarray

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