The Baron Has a Wide Domain
The Equipment: KLH Model 355
The Baron floor-standing loudspeaker, in walnut-veneer enclosure.
Dimensions: 14 by 35 5/8 inches (front), 12 3/4 inches deep.
Price: $399. Warranty: "limited," five years parts and labor.
Manufacturer: KLH Research & Development Corp., 30 Cross St., Cambridge, Mass. 02139.
Comment: Loudspeaker manufacturers have a way of appearing and (perhaps to a lesser extent) disappearing.
KLH is one of the exceptions. It's not the oldest loudspeaker operation, to be sure, but in this fast-moving field, it does claim enough bottle age to be a rarity.
The new Baron (Model 355) is a tower-type, three-way system, well finished on four sides in oiled walnut veneer.
It rests on a short recessed pedestal that serves to protect the color-coded three-way binding post connectors on the bottom. A black knit grille is readily removable to reveal the three drivers and the continuously variable midrange and tweeter level controls.
The driver complement consists of a 10 3/4-inch woofer in a ducted-vent enclosure, a 1 3/4-inch domed midrange, and a 1 3/8-inch domed tweeter. CBS Technology Center reports a smoothly rising impedance curve from a minimum of 4 3/4 ohms, the nominal impedance (at 150 Hz), to a plateau of 11 1/4 ohms (between 2 and 10 kHz) to 14 1/4 ohms at 20 kHz. Over-all, the impedance probably averages close to the 8 ohms at which it is rated by KLH.
With the midrange and tweeter controls at their mid points, the average omnidirectional response in the anechoic chamber is within ± 1 1/2 dB from 90 to 1,600 Hz. The response then shelves off rapidly by 4 1/2 dB and remains within ±2 dB from 2 to 12.5 kHz after which it again falls rapidly. Below 90 Hz, the output rises to a 5-dB peak at 63 Hz before rolling off gradually. The response remains within ± 5 1/4 dB from above 12.5 kHz down to somewhere in the region of 30 Hz-a very broad range. The 300-Hz pulse response is very good; the 3-kHz pulse response shows signs of overhang.
The efficiency of the Baron is somewhat below average with an 77 1/2-dB average omnidirectional sound pressure level at 1 meter with a 0-dBW (1-watt) pink-noise input, 250 to 6,000 Hz. The system is very good in dynamic range, however; it accepts a full 20 dBW (100 watts) of power on a continuous basis without complaint, delivering a 105-dB SPL at 300 Hz. On pulses it easily develops more than 113 1/2 dB peak SPL and can accept 28 3/4 dBW (750 watt) peak input, the limit of the lab amp's capability.
The second harmonic distortion at bass frequencies is about par for the course at low power levels--and just a trifle higher than average at levels near 100 dB SPL. How ever, the more annoying third harmonic is much better controlled than average at all power levels and makes up for the slightly increased second harmonic content at the higher levels. With a 0-dBW input, the second harmonic distortion is under 0.5% for frequencies above 140 Hz and barely exceeds 1% even at 30 Hz. Similarly, the third harmonic content rarely exceeds 0.6% for frequencies above 45 Hz.
At higher power levels-equivalent to 100 dB SPL at 300 Hz-the distortion is more severe but still well controlled, especially in third harmonic content. In general, the third harmonic is below 1.5% from 70 Hz on up except around 500 Hz, where it reaches 2.5%. At 30 Hz, it is only about 3.5%, and is almost negligible above 2.5 kHz. Second harmonic content is more severe--about 5% at 60 Hz and 12 kHz; 3% or less from 160 Hz to 9 kHz.
After some experimentation, we settled on listening to the Barons with the midrange control fully advanced and the tweeter control three-quarters of the way up. These settings provided the best overall balance in our listening room for the majority of music, though with some pop mu sic we preferred the tweeter control fully advanced.
The bass response of the Baron is solid and extended.
The peak in the 63-Hz region is most noticeable in the lower organ registers and on string bass passages, where certain notes are accentuated somewhat. It also adds a bit of heaviness and overhang to the deeper drums. The rather gradual rolloff below the resonant peak, however, extends the usable response to a much lower frequency than most speakers are capable of, and the Baron reveals lower registers with a great deal of authority.
With the midrange control fully advanced, most of the higher voiced instruments-especially the woodwinds-are also reproduced quite well. The transient response is acceptable, but the strong suit of the Baron is its ability to create a realistic stereo illusion--wide and deep. This is an easy-listening system that should appeal to a broad cross section of music lovers.
KLH informs us that roughly forty units of The Baron with serial numbers in the range from A35500101 to A35501585 and 835501586 to B35504001 bear a manufacturing defect of the woofer cone that could cause failure and, conceivably, ignition at high levels of input power. If you own a Baron whose serial number identifies it as subject to this defect and you have not been contacted by the company, you are requested to write to:
KLH Service Division, 30 Cross St., Cambridge, Mass. 02139. Alternatively, if you live outside Massachusetts, you may call the toll-free number 800-225 1157. Massachusetts residents may call 617-491-5060 collect.
---- FREQUENCY IN HZ
(High Fidelity, Oct. 1977)
Also see:
Technics SB-6000A floor-standing speaker system (Equip Profile, Oct. 1977)
Visonik D-50 loudspeaker system (Equip. Profile, Oct. 1977)