Jim:
Have you ever done any comparison between grills on versus grills off?
Just wondering if standard grills or any type does affect sound propagations and results in changes in sound measurements?
Harrison
When we first started building speakers, we only offered grills if requested to do so and then asked the customer to avoid using them when doing critical listening. I personally never use grills (other than perhaps on the woofer section where they have no impact), so I don't think about them much.
We've never done any specific comparison measurements, although they would not be difficult to do (and perhaps I'll do some just for kicks the next time I take some measurements).
If you think about it, there are two factors here that would influence performance.
First, the grill cloth itself would tend to diminish only high frequencies slightly. While I'm sure you could measure the difference, it probably wouldn't be all that audible.
The second issue is diffraction from the grill frames themselves. This, I'm sure, would be more noticeable in the measurements and would tend to be slightly more audible.
Some companies state that they develop crossovers with the grills in mind. I'm sure they do, but I'm equally sure it is more marketing in nature than technical. Usually these differences will tend to be at higher frequencies and will tend to be very minor peaks and dips in the response. Chances are, they are not all that audible. (For example, can you hear a 1/3 db peak centered at 12,867Hz? Probably not.).
Of course, if you don't use grills, it is not at all an issue. So we always recommend removing them when doing critical listening. And we embed magnets in the cabinets so you are not looking at ugly plastic inserts when you do.
- Jim