Signature SE/R Measurements & Analysis Continued

Figure 5. 61-SE/R & 661-SE/R 2 Meter On-Axis Inroom Response, 1/3 octave smoothed

Just for fun, I decided to overlay my measurements of the 61-SE/R and 661-SE/R. As you could see by the graph they measured very similarly which explains why this system has such excellent synergy.

Figure 6. 661-SE/R Impedance & Phase

The 661-SE/R is has a nominal impedance of 6 ohms despite the RBH rating of 4 ohms. I suppose they are playing it safe because of the dip to 4 ohms around 200Hz and the rather steep phase angle around 100Hz. It maintains a +30/-60 degree phase in the audio band and is a relatively high efficient design. It appears to be tuned at around 50Hz. It is highly recommended that quality amplification is used with this speaker for it to truly reach its potential.

Figure 7. 44-SE 1.25 Meter On Center Inroom 30 Deg Off Axis Response, 1/3 Oct Smoothed

It's most challenging to figure out how to measure such an unusual speaker. We measured the speaker at the null (center) of the cabinet 30 degrees off axis at 1.25 meter. Usable bass extension goes down to around 55-60Hz, though these speakers should be crossed over at 80Hz for best results. The suckout between 250Hz and 2kHz is a result of the out of phase driver summation or in this case cancellation. As you move towards the front of the speaker baffle, the response begins to look more linear like the 41-SE . However, in a surround environment, a penalty in linearity is usually a good design trade off for creating a more diffusive speaker system that will envelop the listeners.

Figure 8. 44-SE Impedance & Phase

The 44-SE nominal impedance is 4 ohms, but the speaker dips down to 3 ohms in the upper midrange region. Because of its low impedance, and moderate efficiency (88dB @ 1 watt/meter), quality amplification is strongly advised.