KLH Model Twelve loudspeaker Manufacturer's Comment

Manufacturer's Comment

Any "perfectionist" loudspeaker is a difficult thing to evaluate, and we think that The Stereophile has gone at it very well on balance. But a few very important factors are worth talking about.

There is only one subjective disagreement we have: on the elusive subject of clarity" or "transparency." We certainly agree that, in a direct comparison between the Model Twelve and the Model Nine electrostatic, the former sounds a bit "veiled." We think it sounds less so, however, than any other moving-coil loudspeaker made, with the possible exception of our own Model Five. We would happily pit the Model Twelve against any other speaker in a three-cornered comparison (direct or indirect) with the Model Nine.

The Model Nine, of course, has severe limitations as a practical device. It takes more driving power than any other loudspeaker we know of, and it is not really suited for use at very high levels in a big room. The whole idea of the Model Twelve is to approach as closely as possible the Model Nine's clarity and accuracy, but with far greater efficiency and power capacity. In return for a small loss of transparency, the Twelve allows you the soul-satisfying opportunity of listening at really loud levels once in a while.

The second factor is a more objective one, and one that we think needs real discussion in the future. It has to do with The Stereophile's impression of "hardness" in the sound of the Twelve. The issue is very simple: The amount of high-frequency response needed to do really full justice to the best sound sources these days will produce a less-than-fully comfortable quality with the great majority of lesser-quality recordings.

Most of the discomfort will probably seem to center in the "low" high-frequency region, where most of the "souping-up" is done on modern recordings. It is possible to reduce the annoyance value of this by turning down the 2.5–7kHz switch on the Twelve's contour control, but this won't entirely eliminate it. It is, simply, a function of the speaker having been designed for the most natural sound and optimal dispersion from the best program material.

As a matter of interest, we long ago developed a very small tweeter which was virtually ideal in theoretical performance, and magnificent in "live-versus-recorded" comparisons, but was absolutely unlistenable with any commercial record or tape. One of the challenges for us in designing the Model Twelve was to see just how much of the ideal proportion of high-frequency energy we could design into the Twelve without impairing its ability to reproduce commercial recordings satisfactorily.

With regard to the Model Twelve's bass performance, it should be noted that the speaker was designed primarily as a stereo reproducer, in which application both speakers will reinforce one another's bass output. If the system had been designed for "full" bass from a single speaker, a pair of them would have produced the overly heavy, tubby bass that The Stereophile has criticized in some other stereo pairs of speakers. In most listening rooms, and again assuming reasonably good program material, it should be possible to vary the bass of a pair of Twelves from slightly heavy to slightly sparse, according to taste merely by judicious placement.

We think it is important, particularly if we and other manufacturers are going to attempt genuinely "perfectionist" products once in a while, to clarify in a publication like The Stereophile the problems of attempting to duplicate live sound from commercial recordings In a home environment. "Pleasant" sound is easy to obtain, and is all too often the sole design objective of manufacturers that pay lip service to "ideal high fidelity." But if the public is ever to get anything better than mediocre-fi, it is necessary for at least a few manufacturers to aim for ideal performance, even at the risk of making poor recordings sound as poor as they really are.

Reviewer's Addendum

Our observations about the sound of the Model Twelve were based on a consensus of several listeners, who heard the speakers on a number of different occasions, in varying room locations and on a variety of program sources including some "live," un-souped-up tapes. We plan, though, to continue our tests for some weeks in the future, and if prolonged listening prompts us to revise our opinions of the Twelve (in stereo) we'll have a follow-up report in the next issue.

Afterthoughts on the KLH Twelve, from July 1968 (Vol.2 No.6)

Those of you who read our review of the KLH Model Twelve speaker system will recall that, although we were enthusiastic about certain aspects of its sound, we had reservations about its deep-bass response and what struck us as a certain hardness throughout the middle and upper ranges. Well, since we wrote that report we have done considerably more listening to the Twelves under a variety of different conditions, and must at this point conclude that we were wrong and KLH was right.

The "hardness" that we attributed to the Twelve has turned out to be almost entirely a function of the program material, aided to a small extent by a similar tendency in most preamp/control units, and abetted by our own preference in musical sound.

To eliminate the influence of the preamp unit, we did most of our later listening via direct connection between tape machines and the power amps. Program material consisted of commercially recorded 4-track tapes and a number of original 2-track masters, including some we had made ourselves using professional capacitor mikes. With but a few exceptions, the commercial tapes were still judged to be quite hard and brittle, particularly in massed violin tone. Tapes we had made ourselves were less so, but still seemed to yield more roughness from the strings than we are accustomed to hearing from other top-quality systems or from our favorite concert-hall seats.

Subsequently, some of us were afforded the opportunity to hear several different orchestras from other, less preferred (to us) seats, and we observed much the same kind of roughness from the live violin sounds. The conclusion is obvious.

We are less certain about what brought about the change in the sound of the Model 12's low-bass performance. It did not, and still does not, yield adequate deep bottom in rooms and locations that have been ideal for other similar-type loudspeakers, but we did find some other spots, and some other rooms, in which the extreme bottom of the Model Twelves was fuller, deeper and tighter than anything we have ever gotten from a pair of Janszen Z-600 systems. Indeed, we were introduced to some awesomely subterranean bass passages that we never knew were on the recordings. And this was achieved without any significant increase in mid-bass output.

We found that the Twelves wear exceedingly well, producing neither fatigue nor annoyance with prolonged listening. They still seem to us to lack much of the liquid transparency and detail of good electrostatic systems, and there is something about the velvet smoothness (from most recordings) of the electrostatic top that we find hard to resist.

Under the circumstances, we are obliged to revise our judgment of this speaker and to say that, under ideal conditions, we feel it to be one of the best stereo reproducers available, regardless of cost. This is not necessarily to say that you will prefer it to, say, the KLH Nine or the Altec A-7 under your own conditions of intended use, but it has reproducing capabilities that put it in the same general class as these and similar topnotch systems.—J. Gordon Holt

KLH Research & Development Corp.
984 Logan St.
Noblesville, IN 46060 (2022)
(833) 554-8326

MattJ's picture

I love these retro reviews. Neat seeing how some things have changed, and how some haven't!

partain's picture

This is worth reading for the inadvertent Velcro tribute , alone .

partain's picture

I see that , thankfully , these speakers are available singly .
This "stereo" madness will pass away , in time , as all fads do .

chtgrubbs's picture

The Inflation Calculator says these speakers would cost $4967 in today's dollars!