Wharfedale Diamond 10.2 review part 4


This is the last review part of the Wharfedale Diamond 10.2 loudspeaker and it describes some possible modifications that can be done to improve the loudspeaker performance as well as some listening impressions of the modified loudspeaker compared to the original design.

Disclaimer! I don’t recommend any of the suggested modifications if you still have a valid warranty, since if anything breaks it can reduce your chances of claiming the warranty.

Do the following modifications at your own risk!

Mod level 1:


The level 1 modification contains the following mods:

•    Bitumen pads on the side walls.
•    Sheep wool damping material.
•    Replacing the original loudspeaker steel wire with copper wire.
•    New gasket tapes for the loudspeaker driver mounting.
•    New polypropylen cross-over caps replacing the electrolytic caps.
•    New MOX grade resistors replacing the ceramic resistors.
•    New air core coils replacing the iron core coils (optional).

Enclosure mods:


Bitumen pads:

The bitumen pads make the side walls stiffer and more rigid and they help to eliminate undesirable resonances.

Cut out 2 pieces of 4mm bitumen pads in the size of 32x12cm and 32x8cm for each loudspeaker enclosure. Glue the pads to the side wall as shown in the picture. The larger pad should be used in the back section of the enclosure.

Sheep wool:

Sheep wool has better acoustic properties than the cheap acoustic foam used in the loudspeaker.

Replace the foam with 2 pieces of sheep wool in the size of 100x15cm and 100x10cm for each loudspeaker enclosure. Place the wool as shown in the picture so it covers the side walls, bottom and top walls, where the larger piece is used in the back section of the enclosure.

Internal loudspeaker wire:

Replace the internal steel speaker wire with some copper loudspeaker cable of decent quality.

Gasket tape:

Improve the attached gasket tape for each loudspeaker driver in order to make the mounting to the baffle airtight.

Cross-over mods:


The most important mod to do with the original cross-over is to replace the components placed in series with the drivers e.g. the resistor and cap (R1+C1) in series to the tweeter, but also the cap (C2) in mid-woofer section is valid to change. The coil (L1) in the tweeter section is good as it is and shouldn’t be changed.

Replace caps:

To improve the sound of the loudspeaker, replace the simple electrolytic (C1) and (C2) caps with some decent polypropylene caps like the Mundorf Audiophile MCap which is a very good cap for a reasonable price or use any of your favorite caps of good quality.

The value of 6.0 uF for the (C1) can be achieved by connecting a 3.3 and 2.7 uF cap in parallel.

Replace resistor:

Replace the ceramic (R1) 2.2 Ohm resistor with a MOX grade resistor of good quality like the Mundorf MResist

This resistor adjusts the tweeter level and can be a good idea to buy a couple of extra resistors e.g. 1.8 and 2.7 Ohm in order to test different tweeter levels in order to fine tune it to your liking.

Replace the iron core coil (optional):

This is an optional mod which increases the cost of the mod significantly. By using a good quality air core coil instead of the iron core coil (L2) as in the original cross-over, the sonic performance increases. This is especially noticeable at higher listening levels where the iron core coil can be saturated.

The replacement coil shouldn’t have a higher dcr than 0.3-0.4 Ohm, preferably lower. Don’t go bananas and buy a foil coil or something more exclusive even though it’s sonic superior. The cost increase of such a coil replacement can’t be justified in this loudspeaker design.

Mod level 2:


The level 2 modification contains the following mods:

•    The level 1 mod
•    A new optimized cross-over for the tweeter section.

The new cross-over:

WD10.2_x-over AE

The new cross-over contains a new tweeter cross-over section, while the mid-woofer section is unchanged. However, it’s recommended to change the cross-over components in the mid-woofer section as described in mod level 1.

WD10.2_Freq_15deg Tweeter x-over

The new tweeter cross-over section consists of five additional components compared to the original cross-over. The added C2 cap is used in combination with C1 and L2 to get a steeper high-pass roll-off of the tweeter (see picture). The new electrical third-over filter makes an acoustical fourth-order Linkwitz-Riley topology.

The tweeter level can be fine adjusted to personal preferences by changing the resistor R1. Anything between 1.5-2.7 Ohm is valid to try.

The use of a relative large and deep mid-woofer in combination with a tweeter on a flat baffle makes the relative acoustic center off-set between the tweeter and the mid-woofer, rather large. This means that the original cross-over has a less optimal time alignment between the tweeter and mid-woofer, which results in a bad driver phase tracking below and above the cross-over point.

Unfortunately, the relative acoustic center off-set can’t be compensated for by the new LR4 topology tweeter cross-over, only. Therefore the new tweeter cross-over section (L2+C3 and L3+C4) uses an electrical way to time delay the tweeter to adjust the acoustical center off-set. This is done by using a “Ladder Delay Network” filter circuit, also often called an “All-pass Network”, “Lattice Network” or “Phase Control Circuit”.

WD10.2_Freq_15deg AE x-over vs org
WD10.2_Freq_15deg PhaseWD10.2_Freq_15deg Phase AE

Top: Original vs. Modified cross-over – 15deg off-axis.

Left: Original cross-over – Individual driver phase tracking.

Right: Modified cross-over – Individual driver phase tracking.

The new “Ladder Delay Network” improves the phase tracking below and above the cross-over point considerably, but not perfectly. The new cross-over makes the frequency response more linear and the steeper high-pass roll-off also improves the tweeter power handling.

Summary and listening impressions:


The suggested mods improves an already good budget loudspeaker, but don’t expect it to turn into a high-end speaker. It still uses budget loudspeaker drivers, but if you can get hold on to a pair of second hand Wharfedale Diamond 10.2 or already own a pair where the warranty has expired, please try it. The modifications do improve this nice budget loudspeaker.

First of all this loudspeaker looks a lot more expensive than it is. At this price range, the enclosure looks and finish are beautiful. The loudspeaker has an “easy” listen character with a large portion of warmth. The bass is powerful and the sound stage is good. The mid-range and tweeter lacks some resolution, but on the other hand they never sound harsh even if you listen to less optimal recorded music albums.

Changing the cross-over components as in the mod level 1 increases the transparency and clarity to the sound. Changing to the new tweeter cross-over as in the mod level 2 improves the 3D sound stage in all directions considerably.

Good luck with the modifications!