Hitting Xmax at 12W - WinISD and Seas 5" Magnesium driver

[Sebastian F]

Hey guys, I am running into an excursion problem when modelling a ported 650 cubic inch enclosure with the Seas Excel W15CY-001 5.5" Magnesium cone woofer.

I seem to hit Xmax at only 12 Watts. Is this normal or am I doing something wrong? I downloaded the data from Loudspeaker Database and imported to WinISD without any modification. I use the Butterworth preset.

Here is a graph at 35 Watts. I have not added any filters.

 

[GM]

Beyond its Xmax rating, no driver can handle much power down below Fs/Qts' or ~105.56 Hz per the factory specs, just as WinISD predicts.

(Qts'): (Qts) + any added series resistance (Rs)
PS: FYI/FWIW/YMMV, early on I found enough errors in the Loudspeaker Database to not use it.

 

[Sebastian F]

Beyond its Xmax rating, no driver can handle much power down below Fs/Qts'.

Ah so if I understand correctly, I need to add a highpass filter above qts?

 

[GM]

Qts is the driver's quality/damping factor and where you high pass depends on how much power you want to feed the driver higher up in its mass controlled BW (Fhm = 2*Fs/Qts' = > ~236 Hz).

T/S Explained

T/S Equations and how each one affects the others

 

[Sebastian F]

Qts is the driver's quality/damping factor and where you high pass depends on how much power you want to feed the driver higher up in its mass controlled BW (Fhm = 2*Fs/Qts' = > ~236 Hz).

This may as well be Hieroglyphics to me hahah, I will look at the links, thanks a lot.

 

[GM]

You're welcome! I know the problem well, I flunked Algebra, so no tech school and still mostly 'Greek' to me, though do understand these fundamentals of acoustics from others doing the math and explaining it to me, so I could compare them to the speakers I was originally designing/building using 'rules-of-thumbs', then doing very basic measurements.

Maybe for some, more easily understood from a horn loading POV along with all the extra math (pg. 7):

http://www.xlrtechs.com/dbkeele.com/PDF/Keele (1977-05 AES Preprint) - LF Horn Design Using TS Paras.pdf