Dynaudio Confidence C4 loudspeaker 2007 Measurements
The loudspeaker Wes Phillips reviewed before the Dynaudio C4 was the similarly sized but almost twice-as-expensive Canton Vento Reference 1 DC (Stereophile, November 2006). As I had published a complete set of measurements of the Confidence C4 with my original review, I thought that, to accompany Wes's Follow-Up, I would measure its response in his listening room, using the same spatial averaging technique I have used for the past 20 years. (I take nine spectra across a rectangular window centered on the listening position; the average, weighted slightly toward the center, reduces the impact of position-dependent room resonant effects and has shown a reasonably good correlation with a speaker's perceived balance.)
Fig.1 Dynaudio Confidence C4 (red) and Canton Vento Reference 1 DC (blue), spatially averaged, 1/6-octave, freefield response in WP's listening room.
The red trace in fig.1 shows the result for the Confidence C4, assessed with SMUG Software's Fuzzmeasure program running on my Mac PowerBook in conjunction with an Earthworks QTC-40 microphone and a Metric Halo ULN-2, FireWire-connected preamp-A/D converter. The spatially averaged, 1/6-octave smoothed spectrum is remarkably even from 400Hz to 8kHz, with then a rolloff apparent, this due both to the increased absorption of Wes's room furnishings in the top audio octave and the speaker's limited dispersion at very high frequencies. The Canton speaker (blue trace) is also very flat, though with a slight flare at the bottom of its tweeter's passband and more energy apparent above 10kHz. The Dynaudio's low frequencies, however, are lumpier than the Canton's, with a greater excitation of room modes between 70Hz and 100Hz. Although Wes felt the Dynaudio speaker was missing the very lowest frequencies, the C4 does offer greater bass extension in-room than the Vento Reference, with full output apparent at 20Hz.
Fig.2 Dynaudio Confidence C4 (red) and Canton Vento Reference 1 DC (blue), anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with the complex sum of the port and woofer nearfield responses plotted below 300Hz.
Fig.2 shows the quasi-anechoic responses of the two speakers, averaged across a 30° horizontal angle on the tweeter axis, with again the Dynaudio in red, the Canton in blue. The Canton's slight excess of energy around 2kHz can be seen, which correlated (I conjectured in my comments in the original review) with Wes's finding the speaker to sound very detailed. The Canton's rising response in the top octave in this graph leads to its greater output in-room in the same region, whereas the Dynaudio's relatively large dome tweeters become sufficiently directional above 10kHz to give a trace in this graph that gently slopes down in the top octave and above.
Both speakers have outputs that appear to rise in the upper- and midbass regions. This will be due in part to the nearfield measurement technique used to examine the speaker's output at low frequencies, which assumes a 2-pi (infinite baffle) acoustic loading of the diaphragms. But even so, the Dynaudio has more output in the upper bass than is required for strict accuracy in a room of typical size, and this can be seen in fig.1. Only in an enormous room will the Dynaudio's low frequencies sound optimally balanced with its uncolored midrange and treble.
When I reviewed it, I very much enjoyed my time with the Confidence C4—that Esotar2 tweeter is definitely one of the best around. I'm not surprised that Wes liked it also.—John Atkinson