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Sierra Horizon Intro
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*All measurements taken using DRA Lab’s MLSSA system with RCAI, calibrated ACO Pacific 7012 ½” free field measurement microphone with associated pre-amp and power supply and an automated Outline turntable.

Full-range quasi-anechoic on-axis frequency response

Microphone distance is 1 meter with calibrated sensitivity

Horizon Frequency Response Graph

Horizontal and vertical off-axis graphs plus listening window

Listening window is the averaged response of 5 separate measurements, on-axis, +/- 15 degrees horizontal and +/- 15 degrees vertical. Note: due to the measurement technique, the response below 200Hz is invalid, as represented by the above and below horizontal green bars.

45 degrees off-axis horizontally is within +/- 6dB of on-axis up to 8 kHz, which is about the best there is in a horizontally configured center speaker. The horizontal listening window is +/- 45 degrees, which translates to nearly 20 feet wide (10 feet to left of center, 10 feet to right) at only 10 feet back from the speaker, which is remarkable.

Vertical response is extremely symmetrical, considering this is not a vertically symmetrical driver array, with a +/- 20 degree vertical listening window. This translates to a vertical listening window of ~7.25 feet at 10 feet back, approx 3.5 feet above listener and 3.5 feet below listener. This means the speaker won't sound different if you are sitting or standing and offers great placement flexibility (above or below the TV), while also not being too wide such that floor and ceiling reflections are causing problems.

Horizon Off-Axis Graph

Polar Response

5 degree increments from 0 degs to a full 90 degs off-axis. Note how the critical midrange response remains linear and consistent with uniformly decreasing spl as frequency increases. Also note the lack of tweeter bloom as far off-axis as 45 degrees. Horizontal off-axis shows zero evidence of comb filtering (lobing) at any off-axis angle. This represents an exceptional off-axis response.

Horizon Polar Response

Impedance and electrical phase

Note the extremely clean impedance response (free from wrinkles which would represent various forms of resonances) and linear phase with minimal phase angles. The mild phase angles ensure that this speaker is an easy load for even basic receivers.

Horizon Bode Plot

Energy Time Curve

This measurement is a good indication of overall transient accuracy and stored energy. The graph displays the decay time of a full range impulse. The impulse occurs at approx 2.8ms and decreases uniformly to the noise floor (-45db) by 4.4ms. This represents a decay time of 1.6ms, which is superb. Large diameter woofer cones, woofers and tweeters with poorly designed motor systems and/or heavy mass and poorly constructed cabinets will often contribute to far greater decay times which damage transient accuracy, coherency and overall resolution.

Horizon ETC Graph

Cumulative Spectral Decay

This measurement is similar to the energy time curve but displays a 3 dimensional view such that we can examine the decay time with reference to frequency. It is an exceptional tool to reveal transient accuracy and indicate various problem areas with respect to resonance and stored energy. The CSD of the Sierra Horizon is exceptionally clean with good uniformity.

Horizon CSD Graph