Wharfedale Diamond 225 loudspeaker Measurements

Sidebar 3: Measurements

I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Wharfedale Diamond 225's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield responses. Wharfedale specifies the Diamond 225's voltage sensitivity as 87dB/2.83V/m; my estimate was lower than that, at 85dB/2.83V/m. The speaker's impedance is specified as being "8 ohm compatible," with a minimum value of 4.2 ohms. My measurement is shown in fig.1—an 8 ohm rating would be fair, particularly given the generally moderate phase angle, but the minimum magnitude was 3.87 ohms between 190 and 200Hz.

317WD225fig1.jpg

Fig.1 Wharfedale Diamond 225, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

There is a suspicious-looking discontinuity just above 400Hz in the impedance traces, and I did find a strong vibrational mode on the cabinet sidewalls at 418Hz (fig.2). This resonance was also present on the top panel, at a lower level, but there was also a strong mode at 1040Hz. However, I note that Herb Reichert didn't comment on any midrange congestion that could be laid at the feet of the lower-frequency mode.

317WD225fig2.jpg

Fig.2 Wharfedale Diamond 225, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of sidewall (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

Fig.3 shows the individual responses of the tweeter (green trace), the woofer (blue), and the slot-loaded port (red). The crossover appears to occur at the specified 2.3kHz, with steep acoustic slopes. The rise in the woofer's output in the upper bass will be due to the nearfield measurement technique adopted below 350Hz and the port is tuned to 42Hz, the frequency of the lowest open string of the four-string bass guitar and double bass. The port's output extends a little higher than usual, not rolling off until above 100Hz.

317WD225fig3.jpg

Fig.3 Wharfedale Diamond 225 with grille, acoustic crossover on tweeter axis at 50", corrected for microphone response, with nearfield responses of woofer (blue) and port (red), plotted in the ratios of the square roots of the radiating areas below 350 and 500Hz, respectively.

This response, which was taken with the vestigial woofer and tweeter grilles in place, doesn't look as good as I was expecting from Herb's positive comments—I would have expected the boost in the tweeter's output between 6 and 10kHz to make the sound rather bright. When I e-mailed him to ask if he had reached his conclusions with the speakers' grilles in place, he responded that "with every speaker I always start with the grilles, then remove them. If they sound better with the grilles, I put them back on. With the 225s, all my observations were made without the grilles."

Ah. Fig.4 shows the Wharfedale's farfield response, averaged across a 30° horizontal window centered on the tweeter axis, with (blue trace) and without (red) the grilles. With the grilles, which is how I measured the sensitivity, there is a relative lack of energy between 2 and 6kHz, which goes some way toward explaining why the sensitivity I measured was 2dB lower than the specified figure. But without the grilles, the Diamond's entire treble region is now in better balance with its midrange.

317WD225fig4.jpg

Fig.4 Wharfedale Diamond 225 with (blue) and without (red) grille, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with complex sum of nearfield woofer and port responses plotted below 300Hz.

The Wharfedale's lateral dispersion, taken with the grilles (fig.5), reveals that there is more presence-region energy off axis, and that the peak in the tweeter's output is suppressed more than 25° to the speaker's sides. In the vertical plane (fig.6), a suckout develops in the crossover region 10° below the tweeter axis, which means the Wharfedales should not be used on high stands. However, the step response on the tweeter axis (fig.7) has a very small discontinuity between the decay of the tweeter's step and the start of the woofer's, which suggests that the optimal listening axis will be very slightly below the tweeter axis. The cumulative spectral-decay plot (fig.8), taken without the grilles, is superbly clean.

317WD225fig5.jpg

Fig.5 Wharfedale Diamond 225 with grille, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis.

317WD225fig6.jpg

Fig.6 Wharfedale Diamond 225 with grille, vertical response family at 50", normalized to response on tweeter axis, from back to front: differences in response 45–5° above axis, reference response, differences in response 5–45° below axis.

317WD225fig7.jpg

Fig.7 Wharfedale Diamond 225, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).

317WD225fig8.jpg

Fig.8 Wharfedale Diamond 225 without grille, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

Overall, the Wharfedale Diamond 225's impressive measured performance lives up to what I expect from this classic British brand (footnote 1).—John Atkinson



Footnote 1: Following some failed experiments with home-brewed speakers in the late 1960s, I bought a pair of Wharfedale's two-way Super Lintons, the model with the "purple jellyfish" tweeter, with which I lived happily for several years.
COMPANY INFO
Wharfedale
US distributor: MoFi Distribution
1811 W. Bryn Mawr Avenue
Chicago, IL 60660
(312) 738-5025
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COMMENTS
mrhyfy's picture

I recently bought a pair of Diamond 225's hoping to enjoy some trickle down performance from the Wharfedale Jade 3's....
http://www.stereophile.com/content/wharfedale-jade-3-loudspeaker#iFijTRLaTGgGLhb4.97

I was thoroughly impressed with every aspect of their performance and the perceived bass extension was unbelievable!
The knuckle wrap test seemed to indicate a very solid cabinet.
They seem like a great deal to me!

tonykaz's picture

Well said Mr.JA

Tony in Michigan

bierfeldt's picture

Wonderful review and tells me exactly what to expect from this speaker. Off topic from the speaker, I really liked this paragraph

"A mechanic can sharpen a file by soaking it in dilute acid. This procedure works well—up to a point. Eventually, the file's teeth get too sharp, and become all weak and pointy and bent over, like witches' teeth. That's what bad high-end audio (and a lot of re-mastered high-resolution digital) sounds like to me."

Having listened to some very expensive speakers that I despised and some hi res recordings that sound worse that redbook, this was reassuring that I am sane.

DaleC's picture

"To my ears, all speakers sound like their cone, magnet, and cabinet materials."

So, all kevlar cones sound like they are made of kevlar? If so, you should be able to easily identify them by ear. I will bet a lot of money that is not true.

I give you Exhibit A in the case of "Confirmation Bias".

Thomoz 1's picture

I will not deny that speaker designs using Kevlar drivers can achieve flat frequency response (the measurements prove it), and at least off axis or from another room sound quite wonderful. But sitting in front of the speakers and I myself have a problem with them, similar to the one Art Dudley experiences. It sounds to me as though a sawtooth or fuzzy texture is applied to all the instruments, midrange on down. This applies to B&W, Wharfedale, and Audioquest speakers among others and several of these I heard with their skins on and noticed the "hash" before the driver material was revealed.
After being made fun of by multiple parties over the years, both sales people and other listeners, I finally got to discuss the matter with somebody but completely got it, and his credentials simply cannot be argued with. It is Richard Vandersteen. He has studied speakers that flex partially out of phase as the driver moves backward and forward in a not quite pistonic manner. It was his opinion that Kevlar is entirely too flexible a material to use in this application.

You are however not the first person to ridicule others who observed something that you couldn't. Until new and unique ideas or observations are widely accepted, the few people who can find these characteristics are going to be ridiculed. We just have to roll with the punches.

Herb Reichert's picture

DaleC will you pay me more if I can do it from the next room?

How come audiophiles who can't hear obvious differences want to always bet other people can't hear them either?

(I am certain we can all hear these differences if we sit quietly and pay attention.) Why not try?

bdaddy60's picture

Although I very much enjoyed your review Herb, you are a remarkable wordsmith, so much so, one can palpably imagine hearing the Diamonds as you did, however, like Dale, I too smirked at the thought you know Kevlar when you hear it......I'll take that bet and double it from " the next room ". With the Velveeta Raccoon damning the media for fake news whilst wearing a fake head with hair, I just can't let your assertion go unchallenged.

PapaMax's picture

IMHO Herb is bang on with his assertion you can hear the audible fingerprint of the material a speaker cone Is made from. I've enjoyed having paper cones (AR3a), bextrene (Spendor BC1 and Chartwell Ls3/5a), metal (KEF LS50), polypropelene (various Spendors, ProAc), Kevlar (B&W, Wharfedale) with mixes of metal and silk dome tweeters in many combos of speakers. While I couldn't say I could detect the differences in another room, they cannot avoid resonating according to the physical properties of the material. It is no different to a luthier being able to identify with absolute certainty the resonant characteristic of different woods used in musical instruments. It would defy the laws of physics for any material to be wholly free from any native resonance. Why does this matter? Some materials resonate more musically and with less colouration. The snag is once you detect the recurring resonances, that's what you hear and it is hard to tune out. Personally, I found bextrene slows and thickens the sound with extra harmonics and lost detail, particularly when heavily doped. Metal dome tweeters, try as I might, tire my ears, while I quite happily put up with coarsened sibilances with silk domed tweeters because they sound more musically pleasing to my ears. Maybe Stereophile could conduct a definitive analysis, qualitative and technical?

bdaddy60's picture

Whoa daddy ...another remarkable wordsmith,easily on Herb's level in sensory suggestion by word organization. So Papa Max I'm guessing you're in on the wager and a double or nothing " next room "identifying of woofer material.

JL Main's picture

Listening is an art, and many people do not have the capacity for it. It is a deep practice. The same is true for speaking and communicating through the written word. Thank you Herb for this review and the post WWII audio manufacturing history lesson. I appreciate anyone that can help me navigate the world of tubes, transistors, and boxes. But I really am appreciative of the person that can entertain me and save me money at the same time.

JustSteve's picture

I bought the 220's a year ago and I love them! I use a NAD 316BEE Amp with a NAD Phono Pre Amp a Debut Carbon Turntable. It's a modest set up, but it sounds sweet in my small apartment. After reading every review on them, and seeing how What HI FI rated them Bookshelf speaker of the year in 2014, I was sold. Beautiful sound.

corrective_unconscious's picture

The individual response curve for that bizarre looking tweeter, the horizontal and vertical dispersion plots, and to a certain extent the waterfall in the treble (11k to 14k) do not look very good, imo.

audioguy85's picture

Well despite the measurement you speak of, these speakers sound great to my ears, and I've owned lots. The truth is in the actual listening. They are just so natural sounding with a hint of warmth. They lend their talents to a wide range of music, be it classical, jazz, or rock. The build quality at least on mine is super and they look lovely. I like them so much I bought a second pair in Rosewwood quilted. The first pair is the Walnut pearl. They come highly recommended and Stereophile's reviews are spot on! The best speakers at this price point I Have ever owned. I also own the 220's which are just as good, albeit with less in the base department, but still respectable amounts of base reproduction. I believe Wharfedale has knocked it out of the park on the new Diamonds! If they improve upon them in future revisions, Ill be there!

gasolin's picture

Just got a pair in white, they cost in denmark just a few pennies more than 100 eruros for one speaker, with free shipping both ways and 30 days to return them. They sound really good not classleding deep bass, but for they money they are above avarage in performance to price ratio.

Soundings's picture

Hello gasolin,

Can you tell me where you bought these speakers in Denmark?
I would like to order a pair .

Kind regards.

gasolin's picture

Hififreaks.dk

Soundings's picture

Thank you, i just found them. Price is a little bit higher now but still good.120

gasolin's picture

254 euro https://hifi-freaks.dk/webshop//produkter-hoejttalere-kompakte-hoejttalere-wharfedale-diamond-225-p-1881.html

Soundings's picture

Hi,

It's actually €241 plus 25 shipping to the Netherlands.

Soundings's picture

Hi,

The B stock is still 100 euro's, you have bought those right?
I think that is good as they can only be used for about 3 weeks.
From which country are for the free shipping as i may ask?

Kind regards.

gasolin's picture

no i wrote just a litte more than 100 euros each 100 euros is 745 of my currency.

I just use goodgle to translate it into euros and it was 745

I forgot about the B stock, those are only i walnut

gasolin's picture

Denmark

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