How can you tell if a speaker has impedence dips?


I'm considering running two power amps in bridged mode to increase the power. I've read that the only disadvantage to this is that if the speaker has impedence dips below 8 ohms, this could be stressful to the amp. The speakers that I'm picking up in 2 weeks are the Paradigm Studio 20's which are 8 ohm speakers. How do I know if there are periodic impedence dips or if they stay at 8 ohms consistantly?
meech33
My old 1980s vintage PS Model 2 amps sound WAY better bridged. It's not even close. I'm driving old Rega 2-way speakers with them.
Folks,
It's always a trade off. One amplifier would feel better when it has a normal load and another one would feel better working as a welding machine with literally short circuit(upto 1 Ohm dips) depending on power supply in general so the benefit might be better output characteristics for certain load impedance.
As to voice coils, the smaller the voice coil, smaller ressistance and more current demand to drive it.
Meech33,

Here is the link to the Stereophile review done in 1998:

http://www.stereophile.com/showarchives.cgi?628:3

I'm "sending" you directly to the measurement page showing the impedance & phase plot.

Lowest impedance is 4 Ohms @ approx. 200Hz (mid bass region). Music has a lot of presence in this region & it is a bit unfortuante that the impedance dips this low in that region! Your amps better have the power to compensate! This conclusion is, of course, based SOLELY by looking at measurement results. Many times results mean squat & the speaker is just fine w/ moderate power!

FWIW