Some words are necessary to explain the System devised by Dave Wilson, which since has become something of a standard in High-End Audio. The System took a while to develop and was originaly never intended as a commercial product.

Dave Wilson first developed the Watt as Monitor for his own Recording Company. He needed a Speaker that was portable (unlike the absolute Leviathan - the Wilson Audio Modular Montior - WAMM). Thus the Tiny tot was born. A small heavy truncated pyramid shape with a 6.5" SEAS Bass/Midrange and the then revolutionary inverted Dome-Tweeter from Focal. In order to keep the Speaker portable, Dave Wilson conciously sacrificed Bass-extenion and instead optimised the Speaker for Soundstaging and natural Voices.

As things happen from time to time, people heard the Watt and wanted it. So Dave Wilson started making them in small series. But the problem with the missing Bass remained. After a Subwoofer previously sold with the Watt became unavailable, Dave Wilson decided that it was time to give the Watt a Woofer. So he build that cute little Wilson Audio Puppy (WAP), a surprisingly small Woofer unit, using two 8" Drivers and being just the right height to park a Pair of Watt's on top.

This sold for a while as "System II", had various upgrades until it appeared in it's current Form. With all this, a classic was born (albeit a very expensive one). One thing that makes the Watt/Wap combination so appealing is the fact, that a relativly efficent speaker with a decent Bandwidth was packaged in what is still a domestically acceptable format. While my own pair of copies are a prominent feature of my living room, they are not much more so than the Widescreen TV or the HiFi Rack.

Name a true Fullrange High-End Speaker that pulls this one even today, with the Watt/Wap in production for almost a decade... So, this is realy what attracted me. A nice looking, reasonably unobtrusive Speaker that could get it up on 10Watt! Count me in.

Lacking (just temporarily) the ready green stuff (about $10,000 at least for a good 2nd hand Pair), I had to make my own ones. Want to know how I did it? Read on.

Analysing the WATT/WAP System a number of details emerged. First of all, the Midrange. The more recent Versions (from 5.0 onwards) of the WATT use a Scan Speak 6.5" Driver, notably the 18W8545. This is a Driver with a Paper-Cone to which Carbon Fibres and damping materials habe been applied. Previous versions used a now discontinued 6.5" Driver from Seas, the CA17RCX.

I have heard a range of Speakers using the Scan-Speak 18W8545 in the Midrange (including the Watt/Puppy 5). I have yet to be convinced of the Value of this Driver in this application (Bass-Mid - tthe 18W8545 is a killer Bass Unit). Artificial, cold and generally not very pleasant sounding (to my ears) I really did not like what I heard from the 18W8545. In comparison, the Bass/Midrange Driver used in the earlier Watt sounds very natural, though by no means laid back or romantic.

I believe that the reason for this sound are a pair of not well damped resonances in the 3kHz region. This means that a very low X-Over Frequency is needed and non of the Speakers I have heard does that. One could also implement complex notchfilters.

The other option is to simply ignore the resonances as they do not show up in a frequency response plot (they are well visible in waterfall though) and to hope no-one notices. It seems the designers of all Speakers using the 18W8545 that I have heard to date took that approach.

I decided to have a long hard look at the Seas Catalogue and discovered the CB17RCY which seems to be the direct replacement of the CA17RCX. Indeed, it appears that this driver is used by Wilson Audio for the WITT and CUB speakers. It has few audiophile creditentials, being a boring doped paper-cone, but this driver delivers a extremely natural abd uncoloured midrange.

The Tweeter in the Watt was always a Focal inverted Dome Unit. The earlier Watt used a Glass-Fibre Dome unit, which while extremely transparent, had a few resonances which where pretty unpleasant. The latest Watt uses a pure Titanium Dome, which does not have this problem.

With the pure Titanium Unit discontinued by Focal (at least for general public availability), the Tweeter of choice had to be the TC120Tdx from Focal. By now this unit too is discontinued. The replacement TC120Tdx2 can be used with only minor changes to the Box.

As far as the Puppy is concerned, this is really a simple Design using an extended Bass-Shelf alignment employing two of the renowned Dynaudio 21W-54 Woofers. These are very high quality units, but very expensive and nowadays also somewhat difficult to obtain. Lengthy investigations revealed the Peerless CSC-X Series 8" Woofer as a viable alternative. After testing this Woofer it emerged that apart from a reduced powerhandling and higher voice-coil Inductance it is perfect drop-in replacement for the 21W-54.

With all this in place we had effectively the Driver-Lineup completed. To determine Enclosure Tuning and X-Over Design I employed Computer Simulation tools and published Tests of the Watt/Puppy 3. By using the published Impedance Curves and with known Drivers and their parameters it is easy to determine both the X-Over Design and the Enclosure tuning. After that the only thing remaining was to fine tune some minor changes to allow the use of standard Value Inductors and Capacitors, as well as the acommodation of the slightly different driveunits I used.