Wilson Audio Duette / Custom Crossover Upgrade


 

Stereophile review from 2012:
https://www.stereophile.com/content/wilson-audio-specialties-duette-loudspeaker

Specifications: Two-way, reflex-loaded bookshelf loudspeaker with separate crossover enclosure. 
Drive-units: 8" cone woofer, 1" silk-dome tweeter. 
Sensitivity: 90dB/W/m/kHz. (Note: Look at this spec compared to the measurements below from Danny at GR-Research)
Nominal impedance: 4 ohms. Minimum impedance: 3.96 ohms at 3.1kHz. 
Recommended amplifier power: >20W.
Dimensions: 18.4" H by 9.4" W by 13.75" D. Weight: 39 lbs.
Finish: Automotive paints in non-metallic black, Diamond Black, Dark Titanium, Desert Silver, and Argento Silver Twelve.
Price: $13,900/pair plus $1795/pair for matching stands. Approximate number of dealers: 50.
Manufacturer: Wilson Audio Specialties, 2233 Mountain Vista Lane, Provo, UT 84606. Tel: (801) 377-2233. Fax: (801) 377-2282. 
Web: www.wilsonaudio.com

"Overall, however, the Wilson Audio Duettes produced a sound that allowed all the music I listened to during my visit to communicate very effectively.—John Atkinson"

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I own a pair of Wilson Audio Duette speakers. I found a pair after hearing them at a buddy’s home, who also owns a pair of Wilson Audio Alexia. I thought they were different, cool... sounded BIG. I like 2-way speakers... why not?

Living with them... the Duette are extremely "resolving"... so much "resolution" that I found I needed to listen to them way off axis... speakers spread far apart / pointed straight ahead. With it being a 2-way with 8" woofer, it’s unique. It plays BIG, and is well made... except for the crossover, and the fact that it wants to melt my face.

So, what to do? Well, I sent one of them to Danny Richie at GR-Research. I’ve dealt with Danny before and it’s been a pleasure. One thing Danny will do is measure the speaker you send him, tell you what’s wrong with it, and design a new crossover for it - for Free. There’s no fee for that... you just buy the parts from him and you get a schematic. Fair deal, no doubt.

What Danny found with the Duette is eye opening. The reason the speaker sounds so forward is because the crossover was designed with no baffle step compensation. See the measurements below and the big variance between the low end up thru the midrange volume / highs and explains why they sound so FORWARD and IN YOUR FACE.

So, a new crossover was designed... here is how that has turned out, so far. One issue with the front baffle of the speaker is actually the foam on the front, that is meant to "help". The circular cutout for the foam (not the felt around the tweeter) is contributing to some diffraction / unevenness. I’m going to play with building up the area around the tweeter to smooth that "step" on the front baffle. I’ll measure the difference and see if it helps.

New Measurements for the crossover designed by Danny Richie:

Old Vs New Crossover Measurement

 

New Crossover Driver Response

Spectral Decay

 

Issue with the foam around the tweeter...

Another "Interesting" thing... there are 2 different umbilical cords for attaching the external Novel crossover to the Duette. The manual states the following about their use, and threatens warranty coverage if not used properly:

 

Umbilicals in Question... one for use with "Free Space" resistors and the other for use with "Near Wall" resistors. Different resistors are provided to adjust tweeter output.

So, Danny measured the 2 different umbilicals, to see whether there was a difference. Well, at least in terms of sound... there was ZERO difference.

The language in the manual and this measurement was disappointing, to be kind.

So, on to new crossovers. They are currently being built. I am going to make a custom enclosure for them as they will remain external from the Duette enclosure, like the original design. There will be significant differences in how they connect to the Duette, their orientation, etc. Here is the progress:

 

jim2

@waytoomuchstuff 

What!!!!??  Take a perfectly good expensive speaker and "mess" with it!!??  This is like painting a mustache on the Mona Lisa!

Oh, the humanity!!

I like to use marine grade 1/4" epoxy for our custom crossover boards.  After performing speaker/crossover mods, I look forward to the moment when we sit the customer down for the big reveal.  To borrow a line from Doc Brown (Back to the Future): "When this baby hits 88 decibels, you're going to hear some serious s---!!"

Have fun. 

There are a few unmarked black vans down the street that I don't recognize, but I'm sure it's nothing to worry about.  There were a few phone calls with dead air and just heavy breathing, though... not sure what that's about.  If something happens to me because I've engaged in heresy, I just want everyone to know that I left it all on the field. 😎

Think I’m going to hop off this thread.  Being a “known associate” has its risks.

😀

By the way... I guess there are some not aware... if you search on YouTube you'll find a video where Danny goes thru what he found and did with this speaker. 

Here is a link to it, which I guess is OK to post.  If not then I'm sure AG will delete it:

 

Post removed 

@OP - IMHO  John Atkinson's account of his measurements give a better description of the frequency response of the speaker. BTW re "With it being a 2-way with 8" woofer, it’s unique", there's nothing particularly unusual in two way speaker designs using a 200mm bass/mid unit. It was standard practice in the UK for years before floorstanding speakers became popular.

 

 

The Duette's spectrum, shown as the red trace in fig.1, reveals four features. First is the smooth, gentle rolloff above 5kHz, which is due both to the increasing directivity of the 1" tweeter in its top octaves and to the increasing absorption of the room furnishings. This doesn't mean the speaker sounds rolled off; I agree with John Marks about the speaker's top-octave balance being optimal. Second is a slight lack of energy at the top of the woofer's passband compared with the regions below and above. This is the result of the relatively large woofer's radiation pattern narrowing at the top of its passband, contrasting with the wider dispersion of the tweeter at the bottom of its passband.

 

Fig.1 Wilson Audio Specialties Duette, spatially averaged, 1/6-octave response (red trace), and of Vivid B1 (blue), in JM's listening room.

Third, the lower midrange is suppressed a little compared with the level in the upper midrange. I believe that this is a factor of the speakers being used well away from room boundaries rather than on bookshelves, where boundary reinforcement would tend to fill in this region. Finally, though there are slight peaks and dips between 50 and 300Hz in this trace, due to room modes that have not been eliminated by the spatial averaging, the transition through the lower midrange and upper bass is otherwise smooth, and the speaker offers useful output in-room down to 30Hz. This is excellent bass performance for a two-way bookshelf design.