if I see correctly, your frame has rounded edges where the mylar adheres well when air is sucked in and remains taut.
I ask - is it better to take the measurements by removing the black acoustic sheet?
I ask - is it better to take the measurements by removing the black acoustic sheet?
Yes, edges and corners are all rounded. The black stuff around the opening in the stretcher is neoprene foam that allows the diaphragm to be pressed into intimate contact with the sometimes concave frame of the driver grid.
I am not familiar with the construction of the ES300, so I don't know what the acoustic sheet is, but if you're measuring diaphragm resonance using the technique I used, you'll want just the diaphragm (with or without whatever conductive coating is on it).
I am not familiar with the construction of the ES300, so I don't know what the acoustic sheet is, but if you're measuring diaphragm resonance using the technique I used, you'll want just the diaphragm (with or without whatever conductive coating is on it).
If you're referring to the neoprene on my stretcher, not using the neoprene might give a final resonance on the driver that more closely matches the resonance on the stretcher, but as it is, there's a known 9 Hz offset that works reliably. If I want 86 Hz resonance in the driver to match the factory resonance, I set resonance on the stretcher to 77 Hz.
I'll load them onto the van by this evening, then I'll remove the black acoustic canvas and take some initial photographs. Then I'll do a low-volume test and take a closer look to see how it's assembled.
under the wooden side edges there is the black colored canvas stapled on both sides. I think it is a single long canvas that goes from the back at the bottom to the front at the bottom. the classic black colored acoustic canvas.