Discussion in 'Infinity Loudspeakers' started by geoff727, Jan 18, 2010.
I know I want to read it, post it here, or at least email me a copy. jazzmans AT G mail dot com
Go back to post #56 in this thread. It has already been posted.
Yep, that's the article. I can't believe I missed it when I scanned through this post! Better quality than the 25-year-old Xerox copy I have, too...
Does anyone have the T/S parameters for a 12 inch Watkins woofer? What is the ideal box size? My (5 cu. ft.) QLS1 box "sounds" too big, kind of "boomy".
I asked Mr. Watkins these exact questions. Here are his responses from a back-and-forth email.
My question: Do you have Thiele/Small parameters for your new 12” Watkins woofers? Do you have a suggested sealed box size for them? I measured the internal volume of my Infinity 2.5’s to be about 2.36 cubic feet, but is that an optimum size for these woofers? How about a suggested box stuffing material?
His response: The dual drive configuration circumvents the Thiele/Small parameters. You can have whatever Q you want free from efficiency restraints. The volume of the 2.5 is matched to the LC circuit of the dual drive network. Anything else would have been completely improper. The stuffing in the speaker is also matched to the other dual drive parameters.
Flyers13- Thank you for this info! Nice to get it straight from the horses mouth.
A PDF version of the Watkins white paper is here:
does anybody have a copy of this the link above is dead
Does anybody have a copy of this?
See the attachment here:
I had been using the RS series grey poly coned Watkins in my QLS-1s for quite some time.
My Q2s have the original gray paper Watkins.
I thought the Q2 bass response was more interesting, musical and detailed compared to the QLS.
I replaced the RS polys with the "originals".
Yes and well it should. If you look at the magnet size it gives you the answer, If you use the woofer from the RS 2.5/RS 4.5 it is wrong for the older series like the QLS1, QLS2 and so on. Look at the box size. Bill Watkins said that the new poly series could be used in the old series. This is wrong. The older series had larger boxes meaning you could get away with smaller magnets. Using the the poly cones with larger magnets causes the roll off to begin much to soon in a large box. I could explain this but I will only if I need to. If you don't believe me take a QLS1 and put a poly in one and the old paper cone in the other. The low bass difference will be very apparent. However the mid bass smack will be better with the poly. Always a trade off. In my opinion the paper cones sounded better. Even a rubber vs a foam surround can change the sound. If you have the old cones keep them and change the surrounds if they wear out.
The RS Watkins driver in the QLS-1s produced a woolly boxy type of bass, very unattractive.
I too have talked to B Watkins and he did say all Watkins types would work, but perhaps he meant if they had individually appropriate crossover parameters per design.
There is an interview with Watkins where he says "the 4.5 woofers were dogs".
I thought this statement may have colored my listening and prejudiced me against the RS poly.
Replacing them with originals nixed that.
Separate names with a comma.