![]() The difference between the two responses, which were normalized at 1kHz, is shown in fig.2. To investigate the interaction between the Klipsch's impedance and the amplifiers used to drive it, I measured the speaker's farfield response on its tweeter axis with the Krell (see later), then repeated the measurement with the tubed Shindo Haut-Brion amplifier that Art Dudley used for much of his auditioning. For example, as I always do, I used my solid-state Krell KSA-50 amplifier for the acoustic measurements, which has a measured output impedance of 0.13 ohms from 20Hz to 20kHz. In addition, the very large difference between the average impedance in the bass and the rise to 20.7 ohms at 1.5kHz means that the speaker's perceived tonal balance will be very dependent on the amplifier's output impedance. Despite its very high sensitivity, the Klipschorn will not be at its best with amplifiers that are not comfortable driving 4 ohm loads.įig.1 Klipsch Klipschorn, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.). ![]() ![]() There are current-demanding combinations of 4.1 ohms and ≤3° phase angle at 44Hz and 4.1 ohms and +43° phase angle at 139Hz. Klipsch specifies the Klipschorn's nominal impedance as "8 ohms compatible." This is optimistic: Not only does the speaker's impedance magnitude (fig.1, solid trace) drop to 3 ohms in the midbass and 2.7 ohms in the upper bass, but the electrical phase angle (dotted trace) is sometimes extreme. And at typical listening levels, the drive-unit diaphragms will hardly be moving, which implies low distortion. This speaker will play loudly even with flea-powered amplifiers driving it. (The highest was the Auditorium 23 Hommage Cinema, which features a measured voltage sensitivity of 102dB(B)/2.83V/m.) The Klipschorn's sensitivity is a whopping 18.6dB higher than the sensitivity of the BBC LS3/5a I always measure at the same time I test a speaker (to ensure that I haven't made an error in setup). My estimate was lower, at 101.1dB(B)/2.83V/m, but this is still the second-highest sensitivity of all the speakers I have measured over the past 30 years. Klipsch specifies the Klipschorn's sensitivity as 105dB/2.83V/m, which is extraordinarily high. I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Klipschorn's behavior in the farfield and an Earthworks QTC-40 mike for the nearfield responses. Because of the Klipschorn AK6's bulkeach weighs 220 lbI drove my test gear the 177 miles to Art's place and measured the speaker sitting on a furniture dolly in his driveway. The quality of the voice depends on the harmonic frequencies generated by the tube larger frequencies lead to higher-pitched voices. To see why this occurs, assume for simplicity that the voice is generated by the vocal cords vibrating above a gas-filled cylindrical tube that is open only at one end. Helium, however, has the effect of giving the voice a high-pitched quality, like that of Donald Duck's voice. One way to avoid this danger is for divers to breathe a mixture containing only helium and oxygen. Divers working in underwater chambers at great depths must deal with the danger of nitrogen narcosis (the "bends"), in which nitrogen dissolves into the blood at toxic levels.
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