Stand Loudspeaker Reviews

I performed the measurements with the Klipsch The Nines Primary speaker (serial number 107128623160250). Before I started the testing, I installed the Klipsch Connect app on my iPad mini and paired it with the speaker with Bluetooth. I used the app to set the equalizer controls to Flat, the low-frequency equalization to Other, which is used for a free-space placement away from the room boundaries, and to turn off the Dynamic Bass function, which adjusts the low-frequency extension up or down as the output level changes.

The app identified the speaker's firmware version as "05.00.02" and the DSP firmware as "05.03.04." Apple's USB Prober utility identified the Klipsch as "Klipsch The Nines\000" from "NAE\000," with no serial number string. The USB port operated in the older isochronous mode, and Apple's AudioMIDI utility revealed that The Nines' USB input accepted 16- and 24-bit integer data sampled at all rates from 44.1kHz to 192kHz. The optical S/PDIF input accepted data sampled at rates up to 192kHz.

I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Klipsch's frequency response and dispersion in the farfield, and an Earthworks QTC-40 for the nearfield responses. All the measurements were performed using the line-level analog input and without the grille. This input's impedance was 8.7k ohms. The phono input impedance was close to 12k ohms.

When the speaker is first turned on, its volume is set to –48dB. Klipsch doesn't specify The Nines' sensitivity, just its maximum output, as 115dB at 1m with both speakers operating. With the volume set to +1dB—the app warned that this is "pretty loud" and asked if I was sure I wanted to use this setting—an input signal of 123mV RMS gave a B-weighted spl of 93dB at 1m. This speaker will indeed play "pretty loud."

The speaker enclosure's top panel sounded lively when I rapped it with my knuckles. Examining its vibrational behavior with a plastic-tape accelerometer, I found high-Q resonances at 160Hz, 305Hz, 401Hz, and 617Hz (fig.1). The sidewalls were better behaved, with the only significant resonant mode present at 246Hz. The high Q (Quality Factor) and the low levels mean that there shouldn't be any midrange coloration as a result of this behavior.

The blue trace in fig.2 shows the woofer's response measured in the nearfield. The minimum-motion notch, which is when the back pressure from the port resonance prevents the cone from moving, lies at 36Hz. The output of the flared port on the rear panel (red trace) peaks between 30Hz and 60Hz. The port's upper-frequency rolloff is initially clean, though there is a low-level resonant mode at 600Hz. As the port fires away from the listener, this mode should not have audible consequences. The black trace below 300Hz in fig.2 shows the sum of the nearfield woofer and port outputs, taking into account acoustic phase and the different distance of each radiator from a nominal farfield microphone position. The rise in response in the upper bass, which is due to the nearfield measurement technique, is not as high as usual, meaning that The Nines' woofer alignment appears to be somewhat overdamped.

The Klipsch's farfield response, averaged across a 30° horizontal window centered on the tweeter axis, is shown as the black trace above 300Hz in fig.2. The balance is impressively even overall, with a very slight rise in output above 7kHz and a sharply defined suckout between 19kHz and 25kHz. Repeating the tweeter-axis measurement with MLSSA's maximum sample rate and the wider-bandwidth Earthworks microphone revealed a smaller suckout above 30kHz and a return to full level at 40kHz. The tweeter's output rolled off above 40kHz, which suggests that the analog inputs are converted to digital with a sample rate of at least 96kHz.

Fig.3 shows the effect on the tweeter-axis response of the Mid (red traces) and Treble (blue traces) DSP equalizer controls set to their maximum and minimum positions. (The actual response has been subtracted from these traces so that just the differences made by the controls are shown.) The Mid control boosts or attenuates the output at 1kHz by the specified 6dB or 10dB, while the Treble control applies the same boost or cut at 10kHz and above.

The Klipsch The Nines' horizontal radiation pattern, normalized to the tweeter-axis response, is shown in fig.4. The dispersion is superbly well-controlled, with evenly spaced contour lines up to 9kHz, which implies stable stereo imaging. The pattern widens between 9kHz and 16kHz, which might make the top-octave sound a little tipped up in-room. In the vertical plane (fig.5), a suckout develops in the crossover region 10° above and below the tweeter axis, but the balance is preserved over a 10° window centered on that axis.

The Nines' step response (fig.6) indicates that the tweeter's positive-going step arrives first at the microphone, but at 10.25ms rather than the expected 3.75ms, indicating a latency of 6.5ms. The tweeter's output starts to decay just before the start of the woofer's positive-going step. The Klipsch's cumulative spectral-decay plot (fig.7) is superbly clean overall.

Finally, I used my Audio Precision SYS2722 analyzer to examine the behavior of the Klipsch's single-ended subwoofer output (fig.8). Its response peaks between 20Hz and 40Hz, then rolls off above that region, reaching –6dB at 65Hz with then an ultimate 24dB/octave slope. The subwoofer output impedance was a high 5500 ohms at 30Hz; the partnering subwoofer amplifier needs to have an input impedance of at least 10k ohms.

Overall, the Klipsch The Nines offers superb measured performance.—John Atkinson