Gentlemen,
Just a couple of quick notes. I haven't been very active, but I have watched the threads concerning speakers lately and want to help by clearing up a few misconceptions.
Headroom.
Headroom is not a design element of the speaker. Headroom is the threshhold or point above your current volume level where the amplifier is capable of reproducing the input signal without clipping. Instantaneous peaks in output can and will push the amplifiers output to as much as twice it's rated power. If you are playing into a 100 watt amplifier and using 50 watts of power, then by design you still have 50 watts of headroom available. So, unless the preamplifier stage of the amplifier is producing a distorted signal then the output should never distort. If you are pushing the amplifier to 70 watts output you have decreased your available headroom to 30 watts and you will begin to here the clipping with louder passages depending on your style.
Speaker ratings.
All speakers are not rated equally. JBLs ratings are continuous power for 100 hours equals RMS rating. Program power is the rating of the speaker for very short periods of time, peak is a rating for a few seconds. Most manufacturers rate their speakers in a similar way, although I don't know of any other manufacturers who drive their speakers for 100 hours before rating them.
Regardless, any speaker should handle it's rated output indefinately, or at least for four hours. Now if you rememebr what I said above about amplifiers you'll also understand that even a 50 watt amplifier can destroy a 50 watt speaker with it's 100 watt peaks. It only depends on how long those peaks are sustained. So, if you destroy a speaker rated at 90 watts you have driven that speaker past it's rating far too long, created enough heat to damage the voice coil, or driven the speakers well past it's Xmax/Xmech rating.
WEBER speakers.
I have replaced all of my speakers with either JBL, celestion and Weber speakers. They include JBL D120F, Weber Calaifornia, Weber Blue Dog, Celestion Vintage 30. All are 50 watt or better and all have a unique sound which I have described in the past. My road cabinets are ALL D120 or California. I have one extenion cabinet that currently has a Celestion Vintage 30 in it. I like the low/mid range of this speaker and use it beside or under my D120's only because the it adds low end and for no other reason. If I had to choose a strictly blues/rock speaker it would still be the D120 or California with a very close second to the Blue Dog. I could be very happy with any of those three.
ICE PICKING.
Actually not a term, but the description for cone cry. Cone cry is a condition that occurs when the cone is out of control. Cone cry is always heard as a high frequency first, hence the term ice pick. Cone cry can be controlled by doping the edge of the cone or by placing ribs in the cone. Cone cry is can also be the result of a poorly designed motor assembly. All speakers are capable of cone cry. JBL eliminated cone cry in the D120 by doping the edge, rounding the cone, and by making the cone shallower. ALNICO speakers can develop cone cry as the magnet weakens. Cone cry is always sensed as an unpleasant high frequency artifact whose harmonics do not add to the note(s) being played. Beam blockers DO NOT eliminate cone cry.
Have fun, shop wisely.
