search
Well, I have to say that although the balance was still cold, the glare had gone. Driven by the D-250, the superb stereo imagery and the totally transparent midrange allowed me to hear further into recorded balances than, with one exception (footnote 2), I have ever heard before. The SL600 that has been my reference for three years now is excellent in this area, but sounds veiled beside the CLS. The CLS's upper bass had also improved somewhat, but the relatively limited dynamic range was still a feature, orchestral music producing "cracks" with average levels over 96dB (equivalent to around…
Martin Colloms wrote about the CLS in January 1987 (Vol.10 No.1):
Panel speakers are back in fashion. After years of determined effort on the part of a few established manufacturers, the number of these designs has seen a marked increase, and many new exotic models have appeared. Stereophile has recently reviewed two leading examples of the genre, the $2780/pair Apogee Duetta and the $2490/pair MartinLogan CLS, (both in Vol.9 No.7). To judge by the tone of letters arriving at the magazine's offices, the reviews generated heated controversy. John Atkinson asked me, therefore, to conduct…
If the diaphragms were sufficiently well damped, and dimensionally stable to operate without the subdividing cells, this geometry would approach the ideal. In practice, the cells' boundaries terminate the high frequencies in a nonuniform manner, resulting in an array of treble radiators rather than a uniform whole. Such an array is likely to result in an off-axis polar response with a complex fine structure at high frequencies. This will generate random amplitude and phasing irregularities when a stereo pair is considered.
Electrostatics generally have a finite sound-level limit, due to…
Jack English wrote about the CLS IIA in December 1991 (Vol.14 No.12):
The CLS IIA is the most fascinating product in the MartinLogan lineup and, strangely, the most often overlooked. This fact is particularly intriguing given the CLS's stunning aesthetic appeal. Introduced in 1985 to widespread fanfare within the audiophile community, the original CLS was rightly praised for its literal and sonic transparency. It received rave reviews and became the most sought-after speaker for many an audiophile. Oddly, it has subsequently suffered from its early blockbuster success.
…
...and now, the CLS IIA
Upgrading a pair of CLS IIs to IIA standard costs $150. If you are marginally competent technically, you can install this upgrade yourself. If not, your dealer can do it for you. Of course, the electronics can be shipped back to M-L for upgrading. The IIA upgrade consists of snipping out one component (for each unit) and soldering in a 9" piece of wire. The IIA has a bit more midrange energy and detail than the II. This change moves the sound of the CLS back toward more of the midrange immediacy of the original CLS I.
Upgrading a pair of CLS IIs to IIA standard costs $150. If you are marginally competent technically, you can install this upgrade yourself. If not, your dealer can do it for you. Of course, the electronics can be shipped back to M-L for upgrading. The IIA upgrade consists of snipping out one component (for each unit) and soldering in a 9" piece of wire. The IIA has a bit more midrange energy and detail than the II. This change moves the sound of the CLS back toward more of the midrange immediacy of the original CLS I.
Though there is a $2520 "upgrade"…
Although not immediately obvious, the CLSes are not identical. Each set is actually a mirror-imaged pair. The left- and right-hand vertical sections of each speaker are of different widths. The manual suggests setting them up with the wider outside section toward the side walls of the room, but goes on to say that this is not mandatory. Based upon my listening, I would say the suggested setup is indeed mandatory. With the larger vertical sections toward the inside, residual panel resonances were more obvious, the resultant performance significantly less realistic. I heard more of the speaker…
But that bass...same old story. It was inconsistent in level at different frequencies, and overall lacked adequate power and body. The more I listened to the IIAs, the better I understood the decisions to include a woofer with the Sequel, Quest, and Monolith. The music simply lacked a sturdy foundation. The bottom, at times adequate, was all too often weak or missing. On balance, the speakers had superb "hi-fi" strengths but were tonally lightweight, with significant limitations in the bottom and a residual trace of glare in the upper midrange.
Over time, the speakers seemed to relax.…
Jack English wrote a Followup on the CLS IIA in February 1992 (Vol.15 No.2):
Acoustic Sciences Corporation Studio Traps had been selected specifically to deal with in-room problems identified with the use of MartinLogan CLS IIAs. Specifically, the CLS IIAs had the following problems that could potentially be minimized with the ASC STs: an emphasis of midbass energy, often giving the speakers one-note bass; a lack of sufficient deep bass, causing the speakers to sound lightweight overall; and a beamy/phasey character in the trebles which caused the speakers to have different tonal…
Jack English wrote about the CLS IIZ in June 1994 (Vol.17 No.6):
The $3500/pair CLS is the orphan in the MartinLogan range. Everyone's attention has been drawn to this company's remarkable hybrids: the modestly priced Aerius (reviewed Vol.16 Nos.6 & 10); the very impressive Quest Z (Vol.16 No.10); the popular Sequel (Vol.11 No.12, Vol.12 Nos.8, 9, & 12, Vol.14 No.2); the large, single-box Monolith (Vol.8 No.3, Vol.9 No.3); and the newest, the multi-piece Comment (WCES report, Vol.17 No.4). Each of these speakers marries an electrostatic panel, for the mids and highs, with one or…
Sidebar 1: 1987 Measurements
Looking at the amplifier load factor, the impedance curve (fig.1) is typically "electrostatic." Low at low frequencies, and with no visible signs of the 50Hz diaphragm resonance, it climbs steeply to a harmless 33 ohms by 1kHz. Above this level, the load is almost purely capacitive, falling with frequency at 6dB/octave, reaching 2.5 ohms at 10kHz, and finally bottoming out at a value of 1.6 ohms at 20kHz. Wide-band synthesizers played at high level will not do the amplifier-speaker combination much good, while this load non-uniformity will cause more treble…