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Wharfdale W90 project


Wharfdale W90

Wharfdale W90 project

This project was intended to refurbish a set of Wharfdale W90 “six” way speakers. These speakers were old, had poor frequency extension, a lot of distortion, and a frequency response curve that looked as if a pice of spaghetti had been thrown at the spl chart. Despite this there was some unique concepts that went in to the design of these speakers originally and to be honist studying the designs of this old set of hi-fi speakers was more educational that building the speakers themselves. These speakers featured a rear baffle that was filled with sand in between two layers of wood this clever dampening design if implemented more fully though out the cabinet design process could be a useful tool in making enclosures that are both ridged and dampened. The 12 inch woofers had a unique design as well. Each cab used two woofers in a separate enclosure. This was done for the purpose of tuning one of the enclosures differently. To achieve this Wharfdale filled one of the cones with Styrofoam, this changed the moving mass of the piston (the cone of the driver) it also decreased the surface area. I suspect that this was done to even out the low end frequency response by filling in gaps that the normal woofer had ether in the low end or the high end of its range. these speakers also had a strange mid range and tweeter design. The tweeter and mid range drivers were not placed in a sealed enclosure as most cone mid range drivers and tweeters are rather they were placed in an open box(see pics below). this open box design created a lot of positive and negative summation due to the reflections off of the rear baffle and the sides and tops of the box. these reflections were severely detrimental to the frequency response and over all clarity. After the speakers had been finished I ran in to the same problem; how ever it was nearly as dramatic as in the original design. Due to the fact that  cloth dome tweeters and mid range drivers were selected only the reflections off of the sides of the boxes that caused summation issues. I plan to experiment with this later to see how much moving the front baffle forward improves the frequency response. There is no doubt in my mind that the amplitude of summation is directly related to the depth of the open box. Over all the goal of improving the quality of these speakers was accomplished; the frequency response was improved and the F3 was increased to about 70 Hz from an original extension of about 100 Hz. However the comb filtering effect caused by the cab design makes these speakers sound boxy and dated. In the end these vintage Hi-Fi cabs retained a vintage tone but with greater detail and frequency extension while having flatter frequency response.

Initial Testing

Original Frequency Response At 0 Degrees and 3 Feet.

The Tweeter and The Mid They Could Not Be Tested Alone

Woofer Response

Testing

the full system at 0, 15, 30, 45, and 60 degrees offset

Left right comparison

Vertical off axis at 0, 15, 30, 45, and 60 degrees

Ful system Harmonic distortion percentage

Ful system minimum phase

Full system Waterfall

Tweeter offset at 0, 15, 30, 45, 60 degrees

Tweeter left right difference

Tweeter Vertical At 0, 15, 30, 45, and 60 Degrees

Tweeter Total Harmonic Distortion

Tweeter Impulse Response

Tweeter Minium Phase Response

Mid At 0, 15, 30, 45, 60 degrees offset

Mid Left Right Difference

Mid Vertical Off Axis Response

Mid Harmonic Distortion

Mid Impulse Response

Mid Min Phase

Mid Waterfall

Woofer At 0, 15, 30, 45, ND 60 Degrees offset

Woofer Left Right

Woofer Verticle Offset At 0, 15, 30, 45, and 60 Degrees

Woofer Harmonic

Woofer Impulse
Woofer Min Phase

Woofer Water Fall

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  1. Derek Reeves
    March 4, 2014 at 7:51 pm

    I must say, I was shocked when I first saw this a couple years ago, back when I first got my pair of W90’s, which appear to be the same version as the one shown here (Mine are the early, first-generation version… Dual 3-way, dual front ports and dual sand-filled rear baffles… No rear vent… Alnico drivers throughout… One regular-style W12 woofer and one with the polystyrene diaphragm [Wharfedale referred to it as a “bung” back in the day], both woofers running full-range… This version was only available for a year or so before the rear vent was added and the right front port taken away… And somewhere along the way, it was also changed to a 4-way ratber than a dual 3-way, the upper and lower-bass frequencies being split/divided between the two woofers at some point, but not on this early version… There are at least 5 different W90 versions, believe it or not, if you factor in all the little changes that were made along the way).

    Now, I agree about these not having a ton of extension (like all 50 year old speakers), but there’s gotta’ be something hinky going on with the W90 pair described above, either with the drivers or the caps. First off, these DO NOT work well with modern polypropylene capacitors, which I have to assume the author of this particular blog must have used, either that or modern electrolytics. Mine were recapped with Dayton poly caps when I first got them, but I eventually replaced those with n.o.s. vintage paper-in-oil caps, and let me tell you, the oil caps opened up a whole new world. They became much-more-open, MUCH-clearer, and also somehow much-flatter. I don’t understand how, but they did. And the oil caps eliminated a nasty glare that the modern poly caps had added to the sound. They sounded sickly in comparison to how they are now with the oil caps. Also, these old cone-driven Wharfedales sound their best with driven with tubes, especially the old tube gear from the ’50’s and ’60’s. If solid-state has to be used, go with something tube-like, such as the early Sansui solid-state models or something similar. They don’t like the neutral stuff that much.

    Other W90 owners will agree with me on this, the cone-tweeter W90’s are viciously-good when given a proper old-school restore. Trust me, this is one case where modern caps and modern amplification just do not do them justice. Giving them oil caps and some good, old-fashioned tube power is like throwing on a switch, I kid you not. Specs and analysis in the modern sense is a complete waste of time with these 50 year old speakers. They were designed decades before CAD entered the picture. Back then, the designers used their ears and what little scientific data was available. That said, a pair of oil-recapped W90’s and a Fisher or Leak tube rig is no frigging joke. Jaw-droppingly-good. There are no huge bumps or dips in the response. Everything just sounds right. VERY-right. Rich, ultra-dynamic, and as smooth and anything I’ve ever heard. They have that classic British lushness that’s reminiscent of an old EL84-driven tube amp (like the old Vox guitar amps of the early ’60’s).

    Believe me on this, there is MUCH-more to the old Wharfies than meets the digital, computer-aided eye.

  2. Steve Lawsden
    July 1, 2016 at 7:42 pm

    Can any one tell me the best crossover cap values to use when recapping vintage early Wharfedale W-90 speakers? Got mine recently at garage sale, the early all-alnico ones with no slats on the back, and the lower right woofer in each cabinet has that “bung’ styrofoam….I opened mine up, the caps are 8 mfd and 24 mfd silver cans…other people say theirs are 8 and 12 mfd. etc///Any info would be great, thanks! -Steve

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