Usually the sub makes a bad noise. But if you pay attention to your clipping light on your amp (if you have one) you'll notice it can go off and you wont even notice it. The louder/harder you clip, the more you'll be able to notice.
For me at least...

 

Finally got around to do more testing, 145.4 with one 12" Planet Audio BB.
Just shorted the aeroports to make the box tune to approx. 45hz.
Next, will resin the box and get rid of some corners. But that wont be till it get back.
Florida here I come, yeehhaaaaaa [img]graemlins/gunsarecool.gif[/img]

 

If you have an O scope you could tell if you are clipping. Our vehical last year liked a little bit.

 

now that i realize it...i did get higher scores too when i clipped during a burp, only problem is that it usually ended up that my amps went into protect and the subs kept going with a muffled signal. oh well, a high SPL score is still a high SPL score no matter how you get it.

 

yes..thats right..a "little" clipping goes a long way... but a hard clip will actually make you loose SPL... I wish I had a scope here so I could figure out at what % of distortion the TL will read higher output.