[firewall]

Dear Reader,

I run two (2) SVS PB-12s in my office (12 x 10') with Magnepan Mini Maggies.

I ran a couple of 19 Hz tests and found that between 0-115 dB everything is good...

But when I hit around 120 dB @ 19 Hz, I notice a lot of harmonic distortion.

Is that normal for subwoofers?

That last 5 dB or so gets distorted by that much? I realize that the amplifier is 'givin' it all she's got.' at 120 dB, but what causes the distortion - the driver or the amp?

Your thoughts?

Thanks.

[davidc1]

Could be either or both. Most likely both. 120db at 19Hz is incredibly difficult to reproduce. Probably only a couple of speakers ever have been able to. What is the amp you are using and what is the efficiency rating of the speakers and how far away are you measuring.

[DannyBadorine]

While I haven't done much measuring of 19Hz at 120db, I would say that distortion there would be normal.  120db is incredibly loud and 19Hz is really low.  Remember that live rock shows are around 105db (some more and some less by a few db).  If you're listening over 100db anywhere in your home then you're really pushing it.  Plus, generating a 19Hz frequency inside of any regular size room is a lot for any speaker.  The excursion is massive down there and it takes a lot of power from the amplifier. So yeah, your measurement seems correct and I would say that the driver is performing well.