Monitor Audio Silver 8 loudspeaker Measurements

Sidebar 3: Measurements

I measured the Monitor Audio Silver 8's farfield frequency response using DRA Labs' MLSSA system and a calibrated DPA 4006 microphone. I used an Earthworks QTC-40 microphone for the nearfield responses, its small, ¼"-diameter capsule offering no significant barrier to the free flow of air through the speaker's ports. The Silver 8 is specified as having a sensitivity of 90dB/W/m; my estimate of its voltage sensitivity was 88.5dB(B)/2.83V/m, which is slightly lower. Though the Silver 8's impedance is specified as 4 ohms, its measured impedance magnitude (fig.1, solid trace) remains at or above 5 ohms for the entire audioband other than the region between 100 and 300Hz, where it reaches a minimum value of 3.5 ohms at 165Hz. The electrical phase angle is generally benign, though there is a combination of –34° and 4.5 ohms at 100Hz, a frequency where music can have high energy. A 4 ohm–rated amplifier or receiver will have no problems driving this speaker to high levels.

Fig.1 Monitor Audio Silver 8, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

A significant discontinuity just below 300Hz in the impedance traces suggests some sort of cabinet-resonance problem at that frequency. I did find a strong resonant mode at 301Hz on the top and rear panels (fig.2), and another strong mode at 410Hz on the side panels, level with the midrange unit. Lower, and level with the woofers, the side panels were relatively inert; as Kalman Rubinson commented that "male voices . . . didn't sound overripe," it's probable that these resonances measure worse than they sound.

Fig.2 Monitor Audio Silver 8, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of rear panel midway between ports (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

The solid trace in fig.1 indicates that the twin ports are tuned to 48Hz, which is relatively high considering the Silver 8's fairly large cabinet. However, each woofer is loaded with its own chamber and port, and nearfield analysis of the woofer and port outputs reveals that the two bass drivers behave identically below 500Hz, with the top woofer offering a little more output between 500 and 800Hz. The red trace in fig.3 is a composite showing the summed nearfield woofer outputs below 350Hz and their farfield response on the tweeter axis above that frequency. The minimum-motion notch in the woofers' response occurs, as expected, at 48Hz, and the sum of the port outputs (blue trace) peaks broadly between 30 and 80Hz. Though there is a peak in the ports' output in the midrange, this is well down in level. The woofers appear to be crossed over to the midrange unit (green trace) at around 650Hz (higher than the specified 500Hz), with a steep rolloff above that frequency. Though sharply defined resonant peaks are visible at 5.5kHz and 7kHz, these are well suppressed by the crossover. The tweeter's output appears from fig.3 to be balanced 2–3dB higher than that of the midrange driver, but the sharply defined peak due to its fundamental dome resonance occurs at a commendably high 29kHz.

Fig.3 Monitor Audio Silver 8, acoustic crossover on tweeter axis at 50", with nearfield responses of: midrange unit (green), woofers (red), ports (blue), respectively plotted below 500Hz, 350Hz, 650Hz.

Fig.4 shows the Silver 8's overall response on its tweeter axis at 50", averaged across a 30° horizontal window and spliced at 300Hz to the complex sum of the individual nearfield responses. Other than the slight excess of energy in the tweeter's passband, the response is impressively even and flat. The small rise in the upper bass will be entirely due to the nearfield measurement technique, and the speaker's low frequencies extend to 40Hz, –6dB. KR did describe the speaker's low end as being "in good balance," and wrote that the louder he pushed the twin 6" woofers, "the more power and impact the Silver 8s delivered, without boom."

Fig.4 Monitor Audio Silver 8, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with complex sum of nearfield responses plotted below 300Hz.

The Silver 8's plot of lateral dispersion, normalized to the tweeter-axis response (fig.5), has a textbook appearance below 8kHz, with smooth, even contour lines. The speaker becomes more directional above that frequency, which will tend to compensate for the excess on-axis energy in the same region. In the vertical plane (fig.6), the smooth tweeter-axis response is maintained over a wide angle of ±10°. Only at 15° above the tweeter axis does a suckout appear at the upper crossover frequency, 3.1kHz (rather than the specified 2.7kHz).

Fig.5 Monitor Audio Silver 8, 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.

Fig.6 Monitor Audio Silver 8, vertical response family at 50", normalized to response on tweeter axis, from back to front: differences in response 15–5° above axis, reference response, differences in response 5–10° below axis.

The Silver 8's step response on its tweeter axis (fig.7) shows that the tweeter and midrange unit are connected in inverted acoustic polarity, the woofers in positive polarity. More important than the polarities (see "Letters," November 2014, p.11) is the fact that the decay of each unit's step smoothly blends with the start of the decay of the next step lower in frequency, which suggests optimal crossover design. The cumulative spectral-decay plot on the tweeter axis (fig.8) is superbly clean other than a small degree of delayed energy at 7kHz, this most likely from the metal-cone woofers.

Fig.7 Monitor Audio Silver 8, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).

Fig.8 Monitor Audio Silver 8, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

The Monitor Audio Silver 8 offers superb measured performance at a very competitive price. I am not surprised that KR liked this speaker as much as he did.—John Atkinson

Monitor Audio, Ltd.
US distributor: Kevro International
902 McKay Road, Suite 4
Pickering, Ontario L1W 3X8, Canada
(905) 428-2800

spacehound's picture

Excellent? Yes. Whether you liked the speakers or not is irrelevant. I like your reviewing style, it does not contain the so often seen 'flowery and pretentious nonsense' (You would be hopeless as a wine tester.)

I also liked your 'label collecting' comment. Some once superb British names (and not only speakers) have been 'collected' like this, as you say, and are a sad caricature of what they once were and all sound much the same, how the Chinese think they should sound, even if they have a 'token' UK person in nominal charge of what's going on. Better they were left in peace.

And you said the speakers WERE good. Very good in fact. Further evidence that if you exclude the very low priced rubbish, in loudspeakers there is no connection whatsoever between price and sound quality.

This is demonstrated by the Vienna Acoustics speakers also reviewed, don't come off quite so well at three times the price, admittedly by a different reviewer. So price isn't relevant as it is all subjective. If ANY speakers you came across were truly bad you and the presumably equally honest other guy would say so or not review them at all.

It is also true that some of the totally crazy priced speakers you have reviewed sometimes don't come out too well.

Me, I would be happy with either.

But in fact I bought the Focal Arias, also reviewed here recently. They looked good, sounded fine, and I could take them away from the (local) dealers premises there and then.

The speakers themselves?

The fact that the mid-range speaker is a different size than the bass units is always a clue that the designer knows what he is doing and that the manufacturer is willing to put in the required additional effort.

The finish? The 'wood' ones are very good, using real veneers. They also do vinyl wrapped lower priced 'Bronze' ones very well. I suspect that otherwise they might be fairly similar I have had a Monitor Audio 'Bronze' center speaker for 'AV' for three years and didn't notice this until it was pointed out in a review.

You also reviewed the 'correct' ones. The higher priced Gold and Platinum ones with ribbon tweeters can be a bit piercing! They do this to attract attention in a showroom, a common failing of British designed speakers.

I hope you don't mind my being so long-winded :)

Kal Rubinson's picture

Thank you for your comments. I generally do take the same approach to wine tasting, not testing. ;-)

Ajani's picture

Nice review Kal. Monitor Audio and Revel have been my favourite speaker brands for quite some time. So having read your Revel reviews I was interested to see if you would find Monitor Audio as appealing.

P.S. You might want to check out the just released Revel Concerta2 line, specifically the F36 Tower ($2000 per pair). It would be interesting to see how it compares to the Monitor Audio Silver 8.

Kal Rubinson's picture

I saw the new Concerta2 line and had a brief demo. They sounded nice, looked good and are very well-priced. However, I was disappointed that they are now 2.5 way speakers and not 3 ways.

Kal (somewhere over Wisconsin and on my way home)

geekonstereo's picture

Thank you for the informative review.
Did you or anyone else at Stereophile by any chance test the Silver 6 as well?
The Monitor Audio RX6 received a very favorable review on Stereophile, so am wondering what you think about the model that replaced it.
Additionally, would a 45 Watt RMS at 8 ohm amp be able to drive the Silver 8, you think?
Thanks, again.

geekonstereo's picture

In case anyone stumbles upon this and was wondering...
I did get a chance to audition the two speakers last weekend. The Silver 8 represents a significant step up from the Silver 6. But this doesn't mean the Silver 6 isn't any good.
The Silver 6 sounds excellent for the money, but if you can stretch your budget a little more, the Silver 8 is better deal.
This is all my opinion, of course. It would be best for anyone interested in these speakers to audition both themselves before making a decision.

w1000i's picture

I hope stereophile review the new monitor audio Gold 300 :)

freeextreme's picture

I hope so too :)

Robertas's picture

Anybody can advice:how MA8 sounds with Creek 100A? or anybody can advice speakers for Creek 100 A the same price range? Thank you

RanC's picture

After reading a lot of interviews, I am getting the feeling that these are the speakers I want as the crown jewel in my 7.4.4 setup. I want these primarily for stereo music listening, was thinking of running them with dual B&W ASW610 in stereo to take off some of the load below 100hz (probably an overkill, but hoping it will improve the quality of mid-range a bit without detoriating the low-end).

My main question is, for movies, would these speakers sound disturbingly different from JBL 280 towers which would be acting as the surround speakers? I am obviously looking for better sound as these will replace the 280's as front speakers, but am I wrong in thinking they would blend well enough with the 280's as surround speakers? The elements are almost of identical dimensions, dual 6" woofers vs dual 6.5" woofers, both have 4" mids and 1" tweeter. I do like it when the surround speakers make themself noticed somewhat, but not too much if you understand what I mean.