Fyne Audio F301 loudspeaker Measurements

Sidebar 3: Measurements

I used DRA Labs' MLSSA system to measure the Fyne Audio F301's farfield behavior with a calibrated DPA 4006 microphone. (I left the vestigial grille that covers the woofer in place for the measurements, as it appears to provide the necessary acoustic environment for the tweeter.) For the speaker's nearfield responses, I used an Earthworks QTC-40 mike, which has a small (0.25"-diameter) capsule.

Although the Fyne F301's specified sensitivity is a high 89dB/2.83V/m, my estimated sensitivity was slightly lower, at 86.2dB(B)/2.83V/m. The Fyne F301's nominal impedance is specified as 8 ohms. While the impedance magnitude (fig.1, solid trace) remains above 8 ohms from the upper midrange through to 30kHz, it does drop below 8 ohms in the lower midrange, with a minimum value of 4.77 ohms at 200Hz. While the electrical phase angle (dashed trace) is high at some frequencies, the impedance magnitude is also high at those frequencies. The Fyne F301 will thus be a relatively easy load for the partnering amplifier.

The traces in fig.1 are free from the small discontinuities in the midrange that would imply the presence of panel resonance. However, when I investigated the enclosure's vibrational behavior with a plastic-tape accelerometer, I found a lowish-Q mode at 410Hz on the sidewalls (fig.2), with some other modes present close to 1kHz. These latter modes are too high in both frequency and Q to affect the Fyne speaker's sound quality, but I would have expected the lower-frequency mode to give rise to some midrange congestion. It is fair to note, however, that KM didn't find any problem in this region.


Fig.1 Fyne Audio 301, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).


Fig.2 Fyne Audio 301, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of sidewall (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

The saddle centered on 51Hz in the impedance magnitude trace suggests that this is the tuning frequency of the port on the Fyne's rear panel. This is confirmed by the fact that the nearfield response of the woofer (fig.3, blue trace) has its minimum-motion notch at that frequency. (The back pressure from the port resonance holds the cone stationary at the tuning frequency.) The nearfield response of the port (red trace) peaks broadly between 40Hz and 100Hz, with a clean upper frequency rolloff. However, its output is disturbed by a high-amplitude peak at 800Hz. Standing behind the loudspeaker, I could hear this behavior as a whistle imposed on the noise-like MLSSA signal.


Fig.3 Fyne Audio 301, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response (black), with the nearfield responses of the woofer (blue) and port (red), respectively plotted below 300Hz and 1kHz, and their complex sum (black) plotted below 300Hz.

The black trace below 300Hz in fig.3 shows the sum of the Fyne's nearfield woofer and port outputs, taking into account acoustic phase and the different distance of each radiator from a nominal farfield microphone position. The small excess of upper-bass energy will be due to the nearfield measurement technique, which assumes that the radiators are mounted on a true infinite baffle—ie, one that extends indefinitely in both horizontal and vertical planes.

The Fyne F301's farfield response, averaged across a 30° horizontal window centered on the tweeter axis, is shown as the black trace above 300Hz in fig.3. It is not as flat as I expected from the speaker's pedigree. Depending on which frequency the listener takes as a reference, which will be related to the music being played, there is either an excess of energy between 700Hz and 2kHz, or insufficient energy in the midrange, presence, and mid-treble regions. That KM found the 301's tonal balance "tilted toward the dark side" is probably related to the depressed treble, as is my estimated sensitivity being slightly lower than specified. This graph was taken with sample '922; the response of the other speaker, serial number '921, was very closely matched below 2kHz and above 5kHz, but the depth of the depression between those regions was 2dB greater.

The plot of the Fyne F301's horizontal dispersion, referenced to the response on the tweeter axis (fig.4), indicates that the speaker's output drops off to the sides above 10kHz. Other than the apparent peak at 8.7kHz, which will be due to the on-axis suckout at that frequency filling into the sides, the contour lines in this graph are relatively even throughout the midrange and treble. This will correlate with stable stereo imaging. In the vertical plane (fig.5), the presence-region depression deepens below the tweeter axis but fills in to some extent 5° above that axis. I note that KM did listen to the F301s with his ears roughly ½" above the level of their tweeters.


Fig.4 Fyne Audio 301, 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.5 Fyne Audio 301, 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.

Turning to the time domain, the Fyne F301's step response on the tweeter axis (fig.6) indicates that the tweeter is connected in inverted acoustic polarity, the woofer in positive polarity. The tweeter's step, which arrives first at the microphone, has decayed before the woofer's step starts, but the latter's decay is overlaid with regular undulations. These correlate with some ridges of delayed energy in the upper midrange in the Fyne's cumulative spectral-decay plot (fig.7). The treble is cleaner in this respect, though the suckout at 8.7kHz is accompanied by another ridge of delayed energy. (As always with my CSD plots, ignore the small ridge just below 17kHz, which is due to interference from the computer monitor's line-scan frequency.)


Fig.6 Fyne Audio 301, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).


Fig.7 Fyne Audio 301, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

Though Fyne Audio's F301 had some issues on the test bench, these are not unexpected, given the speaker's affordable price.—John Atkinson

Fyne Audio Ltd.
US distributor: The Sound Organisation
1009 Oakmead Dr.
Arlington, TX 76011

invaderzim's picture

"and flow with the music."

When that happens with whatever system you are listening to it is a really great thing.

Ortofan's picture

... presently available for $406/pr.

A TAS reviewer said that they "might just be the best five hundred bucks you’ll ever spend."




Habu2u's picture

Ah, Yes! Gino Vanelli's "Storm at Sunup"....