Phase Technology PC60 CA LOUDSPEAKER PHASE TECHNOLOGY PC60 CA
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EQUIPMENT REPORT ELECTRONICALLY REPRINTED FROM JULY 2014 ROBERT J. REINA Phase Technology PC60 CA LOUDSPEAKER PHASE TECHNOLOGY PC60 CA hase Technology, a The speaker’s speaker-making di- SPECIFICATIONS vision of MSE Audio linear and subtle 1 based in Jacksonville, delineation Description Two-way, 8 ⁄4" (210mm) D. Weight: PFlorida, celebrated their 30th sealed-box bookshelf 32 lbs (14.5kg) per pair. of low-level anniversary last September, speaker. Drive-units: 1" Finishes Oak, Black Oak. at the 2013 CEDIA Expo, dynamics gave woven-synthetic soft-dome Serial numbers of units by reissuing of one of their well-recorded tweeter, 6.5" RPF/glass/ reviewed 60-050 & 0511. first products, the PC-60 Kevlar-cone, solid-piston Price $1400/pair. Approxi- bookshelf loudspeaker, now instrumental woofer. Crossover frequency: mate number of dealers: 250. updated with new driv- solos a high 2.0kHz. Frequency response: Manufacturer Phase Tech- ers and crossovers. Dick level of realism. 60Hz–20kHz, ±3dB. Sensitiv- nology, 8005 W. 110th Street, Olsher reviewed the PC-60 ity: 87dB/2.83V/m. Imped- Overland Park, KS 66210. in Stereophile in 1984,1 and ance: 4 ohms. Recommended Tel: (855) 663-5600, three decades later, John Atkinson thought it time to revisit amplification: 25–150W. (913) 663-5600. 1 this classic design, especially as the company’s founder, the Dimensions 13 ⁄4" (340mm) Fax: (913) 663-3200. 5 late Bill Hecht, was the inventor, in 1967, of the soft-dome H by 8 ⁄8" (220mm) W by Web: www.phasetech.com. tweeter. The PC60 CA (the CA stands for Classic Audio- phile) intrigued me as well—despite having reviewed audio horizontal and vertical dispersion, is also designed to phase- gear for 30 years and attended audio shows for even longer, align all drivers, acoustically and electronically, to maximize I’d never heard a Phase Technology speaker. And with the the precision of soundstaging and imaging. The new drivers PC60 CA costing $1400/pair—currently the hottest price designed for the PC60 CA include a patented 1" soft-dome point for high-performance bookshelf models— tweeter woven of some synthetic material, and a 6.5" woofer I couldn’t wait to hear it. with a flat solid piston made from a sandwich of RPF, glass, and Kevlar. Phase Tech claims that because solid-piston driv- Design ers don’t exhibit the normal breakup modes, the entire front The PC60 CA features the Absolute Phase Crossover that 1 Robert Harley reviewed the Phase Technology PC-80 in the January 1991 Phase Technology uses in all of its speakers. The topology, issue (Vol.14 No.1). Lonnie Brownell reviewed the PC-80 Mk.II in December originally designed for home-theater speakers to ensure broad 1995 (Vol.18 No.12). MEASUREMENTS measured the Phase Technology tween 3.3 and 6 ohms in the midrange a piezoelectric guitar pickup), I found PC60 CA’s frequency response (fig.1, solid trace), though it remains a series of resonant modes on the in the farfield with DRA Labs’ above 7 ohms in the mid–high treble. top panel and both sidewalls (fig.2). MLSSA system and a calibrated The electrical phase angle (fig.1, dotted Though some of these are relatively DPAI 4006 microphone. I used an line) is generally high, though its more high in level, their frequencies are Earthworks QTC-40 for the nearfield extreme values never coincide with low sufficiently high that I wouldn’t expect response. All measurements were magnitudes. A good 4 ohm–rated am- them to add midrange coloration. performed with the grille removed. plifier or receiver will have no difficulty The single impedance peak in the My estimate of the PC60 CA’s driving this speaker. bass, centered on 55Hz, suggests B-weighted voltage sensitivity was The traces in fig.1 are free from the that this is the tuning frequency of 85dB(B)/2.83V/m, which is signifi- small discontinuities that would imply the woofer’s sealed-box alignment. cantly lower than the specified 87dB. the existence of panel resonances. This was confirmed by the PC60 CA’s The impedance is specified as 4 ohms, Nevertheless, when I investigated the nearfield response (fig.3), which indi- which I think appropriate, the PC60 enclosure’s vibrational behavior with a cates that the low-frequency output CA’s impedance magnitude varying be- plastic-tape accelerometer (similar to is down by 6dB at that frequency. The Stereophile Phase Technology PC60 Impedance (ohms) & Phase (deg) vs Freq (Hz) Fig.1 Phase Technology PC60 CA, electrical Fig.2 Phase Technology PC60 CA, cumulative Fig.3 Phase Technology PC60 CA, anechoic re- impedance (solid) and phase (dashed) (2 ohms/ spectral-decay plot calculated from output of sponse on tweeter axis at 50”, averaged across 30° vertical div.). accelerometer fastened to center of side panel horizontal window and corrected for microphone (MLS driving voltage to speaker, 7.55V; measure- response, with nearfield woofer response plotted ment bandwidth, 2kHz). below 300Hz. PHASE TECHNOLOGY PC60 CA The PC60 CA’s transparency in the lower midrange made it a natural showcase for some of my favorite jazz recordings. midrange presented supple, vibrant holographs of all well-recorded vo- cal music. I’m quite taken by jazz composer and orchestrator Maria Schneider’s recent collection of vocal works, Winter Morning Walks: settings of poems by Ted Kooser composed for and performed by soprano Dawn Upshaw, who’s more usually associ- ated with such composers as Golijov, Górecki, and Harbison. Schneider conducts the Australian Chamber Orchestra and the St. Paul Chamber surface of the cone reproduces all frequencies in unison. Orchestra (CD, ArtistShare AS 0121). Through the Phase When I opened the carton and saw the PC60 CAs, I smiled Techs, Upshaw’s voice was silky and airy, with every facet of broadly. The speaker is available in Oak or Black Oak, and her unique phrasing intact. Rubén Albarrán’s singing on Yo the review samples were finished in the latter—they looked Soy, my favorite album by Mexican supergroup Café Tacuba gorgeous. As I lifted the speakers from their carton and began (CD, Warner Bros. Latin 47374-2), covers a tremendous fondling their fine cabinetry, their dark finish and rounded range of styles. His raspy, nasal, upper-register fortissimo corners reminded me of my old Infinity RS-1Bs ($5500/pair), screeches, as well as his husky lower register in the album’s which were my reference speakers for more than 10 years in few silky ballads, were as realistic through the PC60 CAs as the 1980s and ’90s, and are still making beautiful music for when I last saw Café Tacuba in concert. their third owner, somewhere in Germany. The PC60 CA’s transparency in the lower midrange made it a natural showcase for some of my favorite jazz recordings. Sound I can’t get enough of the ballads on John Coltrane’s Stardust I placed the Phase Techs on Celestion Si stands loaded with (CD, Prestige PRCD-30168), and his tenor saxophone’s sand and lead shot. The PC60 CA’s detailed, uncolored lower register just oozed with rich liquidity out of these di- measurements, continued apparent boost in the upper bass in is impressively flat, though the tweeter looking peak and dip in the presence this graph is entirely an artifact of appears to be balanced a couple of region, though BJR didn’t remark on the nearfield response technique; the dB too high in level. (I note that Bob any coloration in this area. The grille PC60 CA is tuned to be maximally flat Reina did find the speaker unforgiv- introduced some unevenness, the in the bass. Higher in frequency in this ing of recordings that had problems variations reaching ±2dB in the low graph, the speaker’s midrange output in the treble.) There is a suspicious- and mid-treble. A speaker’s on-axis response can’t be examined in isolation; the disper- sion will also affect the speaker’s perceived balance. The PC60 CA’s horizontal radiation pattern is shown in fig.4. Comparison with fig.3 indicates that the dip in the presence region fills in to the speaker’s sides, while the limited dispersion in the top two audio octaves will work against the excess of energy in the same region on the Fig.4 Phase Technology PC60 CA, lateral response Fig.5 Phase Technology PC60 CA, vertical response tweeter axis. Fig.5 shows the vertical family at 50", normalized to response on tweeter family at 50", normalized to response on tweeter dispersion. The speaker maintains axis, from back to front: differences in response axis, from back to front: differences in response 90–5° off axis, reference response, differences in 45–5° above axis, reference response, differences its response over a relatively narrow response 5–90° off axis. in response 5–45° below axis. (±5°) window, suggesting that listen- PHASE TECHNOLOGY PC60 CA minutive bookshelf speakers—I The PC60 CA thought I was listening to ASSOCIATED EQUIPMENT much larger speakers. Likewise, features the I was taken with the woodiness Absolute Phase Analog Sources Rega Planar 3, VPI TNT IV turntables; of the lower register of Marilyn Crossover Immedia, Syrinx PU-3 tonearms; Clearaudio Virtuoso Crispell’s piano on her Amaryl- Wood, Koetsu Urushi cartridges. lis (CD, ECM 1742), which, that Phase Digital Sources Creek Destiny, Lector CDP-7T CD players. through the Phase Techs, had Technology Preamplification Vendetta Research SCP-2D phono stage, the long decay and sustain that Audio Valve Eclipse line stage. I’m used to hearing only from uses in all of Power Amplifier Audio Research Reference 75.