Just clearing up a mis-conception...
The 12" Watkins woofers in my Infinity Quantum 2's produce profoundly deep bass. Not only does the bass go very low, it's also very clean and tight. To get the most out of them requires an amp that can supply the current they need, and the amp must be capable of driving < 2ohm loads.
The voice coils are 2 ohm and 4 ohm.
From:
https://groups.google.com/forum/?hl=en#!topic/rec.audio.opinion/pG2grJ5bqe8
"Bill Watkins
6/28/00
In article <06795498...@usw-ex0104-033.remarq.com>, tony_...@email.com
says...
>bill, i guess the 'short course' here is that your dual-drive
>system lowered the impedance of the woofer around fundamental
>resonance, making it easier for amplifiers to power the woofer
>at and below resonance. yes?
The benefits of the dual-drive are mainly:
1. Extended bass, higher efficiency, smaller enclosure,
or a combination of the above.
2. In any case, a flatter impedance, and almost purely resistive
load in the bass. For example, one can achieve 6 ohms
+/- .5 ohm easily from 10 Hz through 200 Hz if desired.
The typical woofer would vary from 6 to 20 ohms or so.
Thus the dual-drive removes the highly inductive load
of ordinary woofers in the region of resonance and allows
the amplifier to deliver more power into the woofer."
Also:
"Bill Watkins
6/27/00
In article <5PU55.5406$Sn2....@news-server.bigpond.net.au>,
tre...@rageaudio.com.au says...
>Even one of RAO's favourite sons (Bill Watkins) in collaboration
>with Infinity, released some of the most diabolical speakers
>ever let loose on the domestic market (impedance-wise).
>Trevor Wilson
>
www.rageaudio.com.au
---
Trevor, I believe it's time I explained what happened
here. My dual-drive woofer works so:
A second voice coil (vc-2) is wound over the main voice
coil (vc-1) in the woofer, this second coil having a
single layer and very low impedance. Now vc-2 would
normally have an impedance too low for safe operation.
However around fundamental resonance the impedance of
_any_ coil will ~triple. Now we activate vc-2 _ONLY_
in the region of fundamental resonance (around 45 Hz)
and it rises to ~8 ohms or so (being ~2.5 in the
first place) which is safe. This is accomplished with
an LC circuit tuned to 45 HZ and with the Q of the LC
circuit adjusted to provide the response shape and
impedance desired. Please note that the exact value
of vc-2 and the characteristics of the LC circuit give
_COMPLETE_ control of the impedance. The benefit of
the dual-drive may then be taken in extended bass or
higher efficiency in a given size box, or a smaller
box for a given efficiency or bass extension.
Now I set the parameters of the original QLS-1 in a
prototype and shipped it to Infinity. It had a minimum
impedance of 3.2 ohms, acceptable for a 4 ohm speaker.
At that time we were operating a retail store selling
Infinity. Our first shipment of the QLS-1's arrived,
we tested a pair and found the impedance to be
~1 3/4 ohms from ~50 - 80 HZ. Now, the fun begins...
Mr. Nudell wanted a spec down to 20 HZ, he got to
18, as I recall, by adding ~35 grams of mass under
the dust cap, _BUT_ he did not re-tune LC to the
lower resonant frequency, leaving vc-2 operating
somewhat above the new fundamental resonance, and
creating a low impedance in that area. My name
was already on the royalty agreement, which had no
stipulation to cover such... I did voice my
disapproval to no avail.
If you check, you will find our WE-1, built and
marketed by _my_ company had no impedance problems,
and neither did thousands of other speakers we
built have any impedance problems. Perhaps this
makes things clear for the technical people here.
Bill Watkins"
So, just to clarify, the 2 ohm coil should never be seen as a 2 ohm load by the amplifier in a properly adjusted Watkins woofer system. It was, however seen as such in at least one Infinity speaker, due to their mis-understanding the way the Watkins interacts with the system resonance.