Signature SE/R Measurements & Analysis

Figure 1. 61-SE/R 1 Meter Inroom Response 1/3 octave smoothed

As you can see by the graph, these speakers are very linear and neutral. Their 3dB point is around 50Hz and I have had excellent success running them full range in a small room, or crossed over as low as 60Hz to a subwoofer in larger rooms. For multi channel systems, I recommend keeping a global crossover at 80Hz and picking a good sub to compliment them.

Figure 2. 61-SE Impedance & Phase

The 61-SE/SER is a relatively easy load to drive. Judging by the impedance graph, these speakers appear to be tuned just under 50Hz. Their phase response stays within +-30deg phase window for the entire audio band which is excellent. Its nominal impedance is 8 ohms, but does dip down to 4 ohms above 5kHz. For best results, quality amplification with a low output impedance is highly recommended.

Figure 3. 661-SE/R 2 Meter On-Axis Inroom Response, 1/3 octave smoothed

Oriented horizontally (for center channel applications), the 661-SE/R measured surprisingly well. Since this speaker was placed near a backwall, I enabled bass management to limit its low frequency response to around 80Hz. Measured in free space however, I was able to get a 3dB point of around 45-50Hz.

Figure 4. 661-SE/R 2 Meter Off-Axis Inroom Response, 1/3 octave smoothed

Many D'Appolito designs like the 661-SE mounted horizontally suffer lobing issues off axis. I checked a 30-45 degree window at 2 meters and didn't find any ill effects. The response of this speaker remained very linear and exhibited excellent lateral polar response. During listening tests I found this speaker to be very consistent sounding for all of the listening seats which is a sign of good loudspeaker engineering and careful consideration in the design process.