{"id":4465,"date":"2014-05-25T17:42:01","date_gmt":"2014-05-25T17:42:01","guid":{"rendered":"http:\/\/www.audioexcite.com\/?page_id=4465"},"modified":"2014-09-21T20:02:49","modified_gmt":"2014-09-21T20:02:49","slug":"wharfedale-diamond-10-2-review-part-2","status":"publish","type":"page","link":"https:\/\/www.audioexcite.com\/?page_id=4465","title":{"rendered":"Wharfedale Diamond 10.2 review part 2"},"content":{"rendered":"

 <\/p>\n

In part 2 of the Wharfedale Diamond 10.2<\/a> review I will cover frequency measurements, impedance and distortion measurements, but first we start with the official technical specification from Wharfedale.<\/p>\n

Technical specification:<\/span><\/h3>\n

 <\/p>\n

Format: <\/strong>Stand-mount
\nBass\/mid driver: <\/strong>165mm
\nTweeter:<\/strong> 25mm
\nAmplifier power (rec.):<\/strong> 20-100W
\nImpedance (Nominal):<\/strong> 6\u038f
\nA\/V shielded:<\/strong>\u00a0 Yes
\nSensitivity (1W@1M):<\/strong> 86dB
\nNominal Frequency Range: <\/strong>40-24kHz
\nHF Limit (-10dB): <\/strong>44kHz
\nFreq. Fb: <\/strong>42Hz
\nCrossover Frequency:<\/strong> 1.8kHz
\nDimensions (HxWxD) (mm): <\/strong>364x223x301<\/p>\n

Ok, let\u2019s see how accurate the specification is.<\/p>\n

Impedance measurements:<\/span><\/h3>\n

 <\/p>\n

\"WD10.2_Imp<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Blue:<\/strong> Left loudspeaker
\nGreen:<\/strong> Right loudspeaker<\/p>\n

Good impedance similarity between left and right loudspeaker with a 4 Ohm impedance minimum @ 157Hz. The port tuning frequency is 44Hz, slightly higher than the official specification of 42Hz.<\/p>\n

There is a small wrinkle in the impedance plot around 500-600Hz. This could be some sort of mid-woofer chassis or other type of resonance.<\/p>\n

From 300-20000Hz the impedance stays above 5 Ohm without any sharp phase shifts. This should be an easy load for just about any type of amplifier.<\/p>\n

Update! (20140608)<\/strong><\/span><\/p>\n

This is the updated impedance response with new replacement drivers for the right loudspeaker.<\/p>\n

\"WD10.2_Imp<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Blue:<\/strong> Left loudspeaker
\nGreen:<\/strong> Right loudspeaker
\nPurple:<\/strong> Right loudspeaker with replacement drivers<\/p>\n

The impedance plot shows a bit better consistency between left and right loudspeaker with the new replacement drivers.<\/p>\n

Frequency measurements:<\/span><\/h3>\n

 <\/p>\n

If nothing else is noted in the comments, the following frequency measurements of the loudspeaker are made at a 2m distance at tweeter height.<\/p>\n

All frequency response charts are presented in a 50db scale with 1\/24 octave smoothing and the measurements are valid down to 400Hz.<\/p>\n

\"WD10.2_Freq<\/a>\"WD10.2_Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Left:<\/strong> Frequency response on-axis:
\nRight:<\/strong> Frequency response 15deg off-axis:
\nBlue:<\/strong> Left Loudspeaker
\nRed:<\/strong> Right Loudspeaker<\/p>\n

The on and 15deg off-axis frequency measurement shows an overall linear frequency response with a slight dip between 3-5.5kHz.<\/p>\n

We have a sharper dip centered at 13kHz which is most likely caused by the diffraction from the tweeter\u00b4s design ring and grill cover. We have another broader dip centered around 550Hz which correlates to the impedance wrinkles at the same frequencies.<\/p>\n

From the review part 1 I described the right loudspeaker as having a slightly different sonic character as it sounded a tiny bit darker than the left speaker and here\u2019s the reason for it.<\/p>\n

The right loudspeaker has about 1.5dB less output between 4-20kHz. The high frequency response are almost identical, but with lower tweeter level.<\/p>\n

The 15deg off-axis confirms the same high frequency behavior. In the next review part I will try to find the reason for this difference.<\/p>\n

The rest of the frequency measurements shown in this review part will use the left loudspeakers frequency responses.<\/p>\n

Update! (20140608)<\/strong><\/span><\/p>\n

This is the updated on-axis and 15deg off-axis frequency response with the new replacement drivers for the right loudspeaker.<\/p>\n

\"WD10.2_Freq<\/a>\"WD10.2_Freq<\/a><\/p>\n

(click on picture to zoom)
\nLeft:<\/strong> Frequency response on-axis:
\nRight:<\/strong> Frequency response 15deg off-axis:
\nBlue:<\/strong> Left Loudspeaker
\nRed:<\/strong> Right Loudspeaker
\nGreen:<\/strong> Right loudspeaker with replacement drivers<\/p>\n

With the new replacement drivers in the right loudspeaker (green) we can see a much closer match to the frequency response of the left loudspeaker (blue). This small difference frequency response is negligible and the loudspeaker pair now sounds more balanced.<\/p>\n

 <\/p>\n

\"WD10.2_Freq<\/a>\"WD10.2_Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Left:<\/strong> Frequency response on-axis:
\nRight:<\/strong> Frequency response 15deg off-axis:
\nBlue:<\/strong> Left Loudspeaker without front grill cover
\nRed:<\/strong> Left Loudspeaker with front grill cover<\/p>\n

The above frequency responses show the effect of using the front grill cover. The front grill smothers out the 13kHz dip on the on-axis measurement, but overall it introduces more frequency anomalies than without.<\/p>\n

I recommend listening to this loudspeaker without the front grill covers.<\/p>\n

\"WD10.2_Freq<\/a>\"WD10.2_Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Left:<\/strong>
\n0deg = Blue
\n15deg = Red
\n22.5deg = Green<\/p>\n

Right:<\/strong>
\n30deg = Blue
\n45deg = Red
\n60deg = Green<\/p>\n

Nice frequency linearity throughout the off-axis measurements without any off-axis frequency collapses in the upper mid-range or lower treble region.<\/p>\n

\"WD10.2_Freq<\/a>\"WD10.2_Freq<\/a><\/p>\n

\"WD10.2_Freq<\/a>\"WD10.2_Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Upper Left:<\/strong> On-axis individual driver frequency response.
\nUpper Right:<\/strong> 15deg off-axis individual driver frequency response.
\nLower Left:<\/strong> On-axis individual driver frequency response with reverse polarity.
\nLower Right:<\/strong> 15deg off-axis individual driver frequency response with reverse polarity.<\/p>\n

The on-axis measurement shows a broad overlap in the 2-3.5kHz region. The 15deg off-axis measurement on the other hand shows a deeper \u201cnull\u201d when the tweeter is connected with reverse polarity.<\/p>\n

The official technical specification states a 1.8kHz cross-over frequency, while the measurements indicates a cross-over frequency just below 3kHz.<\/p>\n

The mid-woofer has almost a text book LR4 cross-over slope and the tweeter has a LR4 slope\u00a0 down to 3kHz, but below 3kHz it has a broad \u201cknee\u201d in the frequency response that doesn\u2019t follow a LR4 cross-over slope.<\/p>\n

From the measurements it seems like Wharfedale has optimized the design from the 15deg off-axis frequency response with a targeted cross-over point around or just below 3kHz. This sets the cross-over point about 1.1 kHz higher than advertised.<\/p>\n

Distortion measurement:<\/span><\/h3>\n

 <\/p>\n

Measurement setup:<\/strong><\/p>\n