Epos Elan 10 loudspeaker Measurements

Sidebar 3: Measurements

I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Epos Elan 10's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield responses. All the measurements were performed with the clothless "audiophile" grille fitted to the front baffle, which gives a smoothly curved contour in the vicinity of the drivers. The Elan 10's voltage sensitivity is specified as 89dB/2.83V/m; my estimate was very close, at 88.6dB(B)/2.83V/m, which is within the margin of experimental error. The impedance is specified as 4 ohms; my measurement (fig.1) indicates that the Elan 10 drops to that value only in the lower midrange, and that its impedance remains above 6 ohms for most of the audioband. This speaker will be an easy load for the partnering amplifier.

214Eposfig1.jpg

Fig.1 Epos Elan 10, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

There is a small discontinuity in the impedance traces between 400 and 500Hz, and a smaller one just above 1kHz. Looking at the panels' vibrational behavior with a plastic-tape accelerometer (similar to a piezoelectric guitar pickup) revealed resonant modes at 465 and 1110Hz on the sidewalls and top panel (fig.2). However, these modes are low in level and high in Q and frequency, all factors that will work against their having any audible effects.

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Fig.2 Epos Elan 10, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of top panel (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

Fig.3 indicates that the crossover between the tweeter (green trace) and woofer (blue) occurs slightly lower in frequency than the specified 3.2kHz, with what looks like an 18dB/octave acoustic slope for the tweeter feed. Both units are relatively flat within their respective passbands, though the woofer has a slightly elevated region between 600Hz and 2kHz. The minimum-motion notch in the woofer's nearfield output, which is where the cone is held stationary by the back pressure from the reflex-port resonance, occurs relatively high in frequency, at 57Hz. The output of the port (red trace) peaks in textbook fashion at this frequency, and though its otherwise smooth upper-frequency rolloff is broken by some resonant modes in the upper midrange, these are well down in level.

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Fig.3 Epos Elan 10, acoustic crossover on tweeter axis at 50", corrected for microphone response, with nearfield responses of woofer (blue) and port (red), respectively plotted below 355Hz, 1kHz.

The Elan 10's response, averaged across a 30° horizontal window centered on the tweeter axis (fig.4), is basically flat, though with a slight lack of midrange energy. There is very little sign of the usual upper-bass boost that results from the nearfield measurement protocol, which suggest that the low-frequency alignment is somewhat overdamped; ie, tuned for clarity rather than ultimate weight. As BJR noted, "the midbass through the upper bass was completely clean, crisp, and natural, with no trace of overhang." The low frequencies are down by 6dB at 50Hz, which suggests only modest bass extension.

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Fig.4 Epos Elan 10, 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 slight excess of top-octave energy apparent in fig.4 is compensated for by the tweeter's increasing directionality in this region, as revealed by the plot of the Epos speaker's lateral dispersion (fig.5). The Elan 10's output above 6kHz falls off rapidly more than 30° to the speaker's sides. In the vertical plane (fig.6), a deep suckout at the crossover frequency appears more than 5° above and 15° below the tweeter axis. The stands used with the Elan 10s should be tall enough that a seated listener's ears are on or just below the tweeter axis.

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Fig.5 Epos Elan 10, 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.

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Fig.6 Epos Elan 10, 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.

The Elan 10 is specified as using a crossover with second-order electrical slopes for both the high- and low-pass filters. Usually, to compensate for the phase shift in the crossover region that you get with symmetrical second-order filters, the woofer is connected in inverse polarity, which gives a flat response in the crossover region. However, the Elan 10's step response on the tweeter axis (fig.7) reveals that both drivers are connected with positive acoustic polarity. The decay of the tweeter's narrow step doesn't quite blend smoothly with the rise of the woofer's step, which implies that the optimal listening axis will be just below the tweeter. The speaker's cumulative spectral-decay plot (fig.8) is clean overall, but with a very slight amount of delayed energy evident just above 1.2kHz.

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Fig.7 Epos Elan 10, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).

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Fig.8 Epos Elan 10, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

Overall, this is impressive measured performance for a speaker that costs $1000/pair.—John Atkinson

COMPANY INFO
Epos Ltd.
US distributor: Music Hall
108 Station Road
Great Neck, NY 11023
(516) 487-3663
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COMMENTS
Manz's picture

We can safely conclude from the review that the Elan 10 is a better speaker than the Dynaudio X12 in every respect. It's surprising X12 makes the cut in the list of Recommended Components in Class B ,whereas Elan 10 is Class C .I understand sound quality is the only criterion .Moreover Elan 10 is cheaper .

As much as I love and regard your reviews RJR I'm left to much ambivalence construing your recommendations.

Most of us readers do not have trained ears nor can we make much out of the 1 hour auditions we have the privelege to .So we look for expert recommedations .

So I would request you to suggest one speaker (only one) in the range of 1000USD for a smallish room (8' by 12') for listening to mostly elctronica ,rock and ocassional jazz and blues .

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