Max SPL is the point where cone excursion reaches it's maximum value. SPL Sound Pressure Level. Cone excursion can generally becomes a problem in the bass region. Driver data sheets mention it as Xmax in mms but it may be the point that causes 10% distortion or when mechanical parts hit each other.Trying to move air at 30Hz needs a lot of cone excursion - more than this particular driver can really provide. A larger driver would need less cone extension. Another model of driver, a little larger, more expensive can handle more cone extension but might still not cope with frequencies that low.
F3 is the -3dB frequency response drop point, you might see F6 or even F10 mentioned.
On a driver data sheet SPL is usually specified at 1watt at a distance of 1 meter with the speaker mounted in a huge baffle.
Do your design work first.
F3 is the -3dB frequency response drop point, you might see F6 or even F10 mentioned.
On a driver data sheet SPL is usually specified at 1watt at a distance of 1 meter with the speaker mounted in a huge baffle.
Do your design work first.
So having the f3 this low may damage the driver in the long run as it causes lots of extension? Dose this mean I’ll need to put a filter on it to limit this or would it be a better idea to find a driver with a larger xmax that can handle more cone extension? I’m going to keep with the same size driver though as the box I’m using has a cutout for a 15inch subwoofer
It's something that needs consideration via simulation.
That box will set / strongly influence the frequency range that the speaker can handle. Is it vented or sealed? If vented what frequency is the box tuned to.
Add to both aspects - which 15" speaker
You are simulating so that should provide the info you need and I assume it simulates the box. Boxsim has a tab they call max spl. It shows that as well as max voltage drive across the frequency range. I'm not sure how the voltage drive on the other tabs is changed. WinISD has a max cone excursion graph - a red line that coincides with Xmax. Default drive is 1watt but that can be changed to see what happens with cone excursion as power levels are increased. Your simulator should have something similar.
I was "Xmax'd" on the drivers I bought. Spec said 7mm so thought that could be ok. Visitron speaker and on this one they don't give the 10% distortion limit in the spec sheet. Boxsim sets it to +/-2mm when the driver is loaded. The 7mm total is the mechanical limit. I assume +/-2 is the distortion based figure.
The box was vented however for simplicity sake of my first crossover design I’m going to seal the ports to make the enclosure sealed as I’m not sure what the box is tuned to. In a few years I may consider remaking the boxes as vented boxes and properly calibrate the frequency running to that of the response of the subwoofer