Test Report: Triad Speakers Page 4
Speakers morphed into unusual form factors have inevitable compromises, but Triad Speakers has made smart compromises with the Designer Series - sometimes even delivering sound quality that makes you question the necessity for larger, more conventional speakers. Every home has at least one place (or five or 10) where one of these speakers would come in mighty handy.
Frequency response (at 2 meters)
Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input)
Subwoofer output (CEA-2010 standard)
Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters)
Even though the Designer Series speakers can be used as surrounds or front speakers, I decided to measure them using the weighting curve we use for front left/right speakers. This way, you can better compare them to the Mini LCR 3.0 and to conventional in-wall speakers. (This weighting curve places a heavier emphasis on measurements taken at 30° off-axis-the sound most likely to reflect off the side walls of a typical listening room.) Measurements were made at 2 meters to ensure that full effects of cabinet diffraction and front panel reflections were included. The Mini LCR 3.0 was measured on a 6-foot stand, and also attached to a large plywood panel to simulate the acoustical effects of wall-mounting. I measured the Mini LCR 3.0 with the grille on, figuring it will always be used that way. To measure the Designer Series speaker, I mounted the faux wall I built for it directly onto my measurement turntable, and surrounded the edges of the wall with attic insulation to minimize diffraction off the corners of the wall. The supplied in-line filter/current limiter was connected for all measurements of the Designer Series. These tests gave quasi-anechoic results down to about 300 Hz. I placed a microphone close to the Mini LCR 3.0's woofers and to the Designer Series' front panel in order to measure bass response, then spliced those responses to the averaged and smoothed quasi-anechoic response curves. The SlimSub/4's driver was close-miked.
The frequency response curves of the Mini LCR 3.0 show considerable treble roll-off. The response starts to fall above 1 kHz; shows a big dip between 1.3 and 4.2 kHz (caused by interference between the woofers at 30° off-axis); and rolls off consistently at higher frequencies. (These measurements are for the left channel; measurements for the center channel were almost always within 1 dB on-axis.) Wall-mounting the soundbar causes a peak of +3.1 dB at 790 Hz with a corresponding dip of -6.0 dB at 450 Hz. Bass output is good, with usable response down to 63 Hz, making this speaker easy to mate with a subwoofer.
The Designer Series in-wall has a rather rough frequency response, with notable peaks between 130 and 230 Hz; at 675 Hz; and at 15.6 kHz. The curve you see here is averaged and smoothed, but the individual responses are hashy, and the off-axis responses are equally hashy but in different ways. Bass is weak, with usable response down to only 125 Hz.
Impedance of the Mini LCR 3.0 is moderate-even at its lowest point of 3.3 ohms, phase shift is just -15°. Plus, sensitivity is reasonable at 87 dB, so this soundbar should be easy for almost any receiver to drive. Impedance of the Designer Series runs unusually high, but its sensitivity is low at 78 dB. That might make it a little difficult to use with some of the low-powered, 20-watt-per-channel mulitroom amplifiers out there. However, given that most multiroom systems are used only for background music, I expect few users are likely to find this speaker too much for their amp to handle.
For our subwoofer output measurements, we've decided to switch to the recently developed CEA-2010 standard, which cites single average dB results for ultra-low bass (20-31.5 Hz) and low bass (40-63 Hz). The CEA-2010 technique involves playing special 6.5-cycle bass test tones through the subwoofer; placing a measurement microphone on the ground at a distance of 1 meter; and watching the result on a real-time analyzer. When one of the distortion harmonics reaches a certain threshold (for example, -10 dB for 2nd harmonic, -15 dB for 3rd harmonic, etc.), the dB level of the fundamental tone is recorded. Measurements are taken at 20, 25, 31.5, 40, 50, and 63 Hz. Although this technique isn't necessarily better or worse than the one we were using (in many ways they're similar), we've adopted it because it's an industry standard that others can easily replicate. For the next two issues, we'll cite measurements taken both ways so you can see how they compare.
Although the SlimSub/4 has fairly deep frequency response, its maximum output is limited by its slim driver and small box. The good news is, due to boundary reinforcement you can expect 3 to 6 dB more output when the sub is actually mounted in a wall-plus another 6 dB more ouptut if you add a second SlimSub/4 enclosure. Measured by the CEA-2010 standard, output averaged 73.1 dB from 20 to 31.5 Hz and 88.9 dB from 40 to 63 Hz. Measured by our old standard, max SPL at 10% THD is 100 dB at 63 Hz, while average SPL is 91 dB and deepest useful bass response is at 31.5 Hz. -B.B.