Test Report: Sunfire Atmos Subwoofer Page 3

Bottom Line

There’s nothing else on the market quite like the Atmos. You really can hide this little sub almost anywhere, and it really does provide substantial bass output. You pay a lot for it, but those big bucks buy you a minor miracle.

Extended Test Bench

Frequency response

36 to 96 Hz ±3 dB

Bass output (CEA-2010 standard)

• Ultra-low bass (20-31.5 Hz) average:  81.8 dB

20 Hz        NA
25 Hz        76.1 dB
31.5 Hz     89.5 dB

• Low bass (40-63 Hz) average:  108.4 dB

40 Hz    102.5 dB (L)
50 Hz    111.9 dB (L)
63 Hz    108.3 dB (L)

I measured the frequency response of the Atmos using ground-plane technique with my Clio FW audio analyzer in log chirp mode. Measurements were done with the auto EQ deactivated. The Atmos delivers a fairly narrow response with almost all of its output focused in the second octave of bass (between 40 and 80 Hz). With the crossover point set to 65 Hz, the low-pass crossover function measures -24 dB/octave.

I performed the CEA-2010 output measurement with auto EQ bypassed. Measurements were made at 2 meters; I added 6 dB to scale the measurements to the 1-meter reporting standard mandated by CEA-2010. An L appears next to measurements in which the results were dictated by the unit’s internal limiter. Averages are done in pascals per recent amendments to the CEA-2010 procedure.

The output in the low bass (40-63 Hz) range is 108.7 dB, comparable to that of a good 8-inch or inexpensive 10-inch subwoofer, and better than Sunfire’s rated 106-dB max output. Unusually, the output at 50 Hz is substantially higher than at 63 Hz; I wonder if this is the cause of my perception that the Atmos’s upper-bass reproduction is a little lean. There wasn’t enough output at 20 Hz to get a measurement, so per CEA-2010 procedure I subtracted18 dB from the 25-Hz result to calculate the ultra-low bass (20-31.5 Hz) average of 81.8 dB. These numbers are lower than I expected from my subjective experience with the Atmos, but of course probably higher than any sub this small has ever achieved.

As I noted in the review, I measured the in-room frequency response with the Atmos in the corner of my listening room before and after activating auto EQ. The extra chart included here shows the before-EQ response (green trace) and the after-EQ response (blue trace). as you can see, the auto EQ does a pretty good job of equalizing the level of the main room modes at 40, 65, and 85 Hz.  — B.B.

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