Waffle Grille - waste of energy?

[Drone]

I was mic'ing up a cab with a waffle grille today, and I recalled recent debates about whether you should have them off or on for recording, but I got to wondering, there's more grille than there is hole, does this mean that 50% of the energy of the speaker is wasted in reflections?

[Bro Shark]

Take one off, mic both, compare, post results.

[Drone]

It wasn't so much for recording, though I do wonder if it causes some kind of comb filtering or some such weirdness, though it's a large wavelength versus a relatively small opening.

I was just meaning the volume or SPL produced by an amplifier, is a waffle grille wasting a good part of it, or is air forced through the gaps.

I guess I'm trying to relate my vague memory of high school physics, with the studio.

[dfuruta]

does this mean that 50% of the energy of the speaker is wasted in reflections?

No way, and that's pretty easy to measure (like Bro Shark suggests). I wouldn't worry too much about comb filtering, either, since there's not much going on with most guitar amps above, what, 7k, and low frequencies are going to pass right through...

[crow]

My half-informed opinion would be that it would have to be more rigid to have much effect on the sound. Also, people seem to agree that if you can breathe through a fabric, you can hear through it. Subjectively, I've never felt that they made any sonic difference.

[Jim Williams]

Mic it one foot or more back and all those frequencies combine into what we players call 'our sound'. Otherwise you only pick up a partial of the sound.

[Drone]

You know, stupidity being what it is, I just realised that mics tend to have a mesh grille on them too

I'm thinking at least 6 feet back, as this guitarist uses a 18" ported reflex (the cab in question with the grille) and a couple of olde-style Jamaican scoop horns. I was going to close mic the 18" and distance mic for the subs, but the sound from the 18" is just weird on it's own, I suppose I could use it to brighten the guitar sound if I need it.

I've got a PZM about four feet back, on the floor, and a 58 close mic'ing the cab (yeah my mic collection is this small) just now, but I need to put an XLR on the PZM as I'm not getting enough level using 1/4" into line in on my desk (Soundcraft 500).

[supafuzz]

and here I thought you were going to recommend a mod for my waffle grille so I can make golden brown waffles perfect every time...