KEF Reference Series 103/4 loudspeaker Equipment

Thu, 06/18/2015

kensargent's picture

I think what you mean is something other than that the woofers in the KEF 103/4 operate IN phase. For there to be any pressure generated in the central chamber, and thereby generation of any velocity at the port, the drivers must be OUT of phase, both electrically and mechanically. That is to say that as one of them moves away from its' frame, the other moves toward its' frame. As a result, the pressure in the central chamber is increased in one half of a cycle, and decreased in the other half of a cycle. This is the actual arrangement that would create the situation you describe: when the pressure is at maximum in the central cavity, it will be at minimum in the opposing cavities at the ends of the enclosure.

The rod connects the woofers' frames, surely, as this arrangement would, in fact, reduce vibration as the manufacturer states, but only if the cones were moving opposite each other. If the woofers were moving in phase, the rod would serve only to equalize, or average, the vibration, but not reduce it.

There are some arrangements in professional loudspeakers that put the woofers out of phase both mechanically and electrically, on an ordinary baffle, with one facing into the cabinet (front-loaded) and one facing out (rear-loaded.) In this arrangement, the advantage is said to be a cancellation of nonlinearities caused by the woofers' suspension, with the result reportedly being measurably lower distortion.


KEF Reference Series 103/4 loudspeaker

By now most readers will be familiar with the relatively new tuned-cavity method of low-frequency loading. Such designs have popped up all over the place of late, especially in those little satellite/woofer systems, but KEF can rightly lay claim to generating the design's theoretical basis, as JA described in his review of the KEF R107/2 loudspeaker in Vol.14 No.5 (May 1991). Essentially, the technique consists of loading the rear of a woofer in a conventional fashion—usually a sealed box—but also loading the front of the driver into another enclosure, ducted to the outside. Basically, the design acts as a bandpass filter with its response centered on the port-tuning frequency. The rolloff is smooth and rapid on either side of this frequency, providing a natural low-pass characteristic but thereby virtually mandating a three-way system. If properly designed, this configuration offers a number of theoretical advantages. The radiating element is actually the air in the port, which is low in mass. Low distortion is possible, as is relatively high sensitivity.
Mon, 06/01/1992

LAST Record-Preservation Treatment Manufacturer's Comment

Thu, 06/18/2015

Allen Fant's picture

Interesting- LA.
is there a similar product for CD ?

corrective_unconscious's picture

Sure, there are these green magic markers....

leok's picture

After using Last 2 (record-preservation treatment) I find the amount of anti-skate force required to maintain right-left stylus force balance is significantly reduced. Anti-skate on my Graham 1.5 is set to almost minimum. Without the Last treatment, mid-range anti-skate was required. I interpret this as indication of reduced stylus/record friction.

I also find record sound improves as described in the above article.


LAST Record-Preservation Treatment

LAST (Liquid Archival Sound Treatment) is a record treatment developed by one Dr. Catalano, which promises to retard dramatically the wear of vinyl discs. I don't feel that the advent of true digital discs will diminish the importance of LAST; on the contrary, as this century comes to a close many stereo records will be in their 30s and 40s and in need of as much preservation as possible, if the sounds and performances we treasure are to be preserved.
Sat, 05/01/1982

A Plague Upon Our House

The summer of 1975 will be remembered by us, with no fondness whatsoever, as The Time the Roof Fell In. Or the Murphy Months, or the Period of the Plague Upon Our House.

Ye Editor can recall from the days of WWII hearing and reading about the depredations of some mischievous sprites called Gremlins, who would cause aircraft hatchcovers to jam and control cables to get hung up at the worst possible moment, but I don't think I ever really did believe in Gremlins. I think I sensed somehow that the mishaps attributed to their malevolent machinations were too capricious to be the work of thinking, calculating little spirits. But I was not clever enough to put my finger on what was going on. That had to wait for a gentleman named something-or-other Murphy, who was (to my knowledge) the first person to put a tag on it, and to formulate a basic law about it. The tag was "the perversity of inanimate objects," and the law was "If anything can possibly go wrong, it will."

Fri, 08/01/1975

Recording of June 1982: Encores à la Française

682rotm250.jpgMichael Murray: Encores à la Française Works by Couperin, Dupré, Gigout, Franck, Widor, J.S. Bach, Vierne, Lemmens
Organ at Symphony Hall, Boston
Telarc Digital DG10069 (LP), 80104 (CD, released in 1990). Robert Woods, prod., Elaine Martone, assistant prod., Jack Renner, eng. TT: 65:46 (CD).

This is another winner. Michael Murray's superior performances are or should be well known to all by this time. This recording of Encores in the French style covers a wide gamut of registration and mood, ranging from the large and full-blown sonorities of Franck's Pièce Héroique, the Toccata from Widor's Organ Symphony 5, and Vierne's Final from the Symphony 1 in d to the light and nimble Scherzo of Eugene Gigout and the technically demanding Musette by Marcel Dupré.

Tue, 06/01/1982

The July 2015 Issue is on Newsstands Now

Bel Canto's extraordinary Black amplification system is featured on the cover. Combining state-of-the-art class-D monoblocks with an all-digital preamplifier, the Black sounds and measures as good as it can get. At a price, of course—but at the other end of the price spectrum, we review Creek's Evolution 100A integrated amplifier, as complete in its way as the Black is in its. These are not your father's amplifiers.
Mon, 06/15/2015

Blood and Freedom

Fri, 06/12/2015

Ornette Coleman (1930–2015)

Ornette Coleman, the great alto saxophonist and composer, died yesterday at the age of 85. His great jazz quartet of the late 1950s and early '60s—with Don Cherry on pocket trumpet, Charlie Haden on bass, and Billy Higgins (sometimes alternating with Ed Blackwell) on drums—revolutionized jazz, shifting it away from chord changes to structures built more around melody, rhythm, and harmonic suggestions not confined by set chord changes. And while some of his followers may have descended into noisy chaos, Ornette himself rarely went that route and, in fact, in the '90s, stepped up to a new level of lyricism, culminating with his 2006 album Sound Grammar, which won that year's Pulitzer Prize for music.
Fri, 06/12/2015

Aurender Flow D/A headphone amplifier Measurements

Thu, 06/11/2015

petest's picture

I really like the looks of it, nice and sleek. Even though it looks a bit like a thermostat. :)
Is this amplifier still suitable to use with cheaper earbuds, like up to $150 range, like here I have Sennheiser 800s but want to use them with earbuds too.



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