I use a mixture of nearfield, in-room, and quasi-anechoic FFT techniques (using the DRA Labs MLSSA—pronounced "Melissa"—system from DRA Labs) to investigate objective factors that might explain the sound heard. (Stereophile's measuring microphone is a calibrated DPA 4006.) The 3000's impedance phase and amplitude were measured using Stereophile's Audio Precision System One. Looking at fig.1, it can be seen that the speaker is definitely best rated as a 4 ohm load, the value dropping below 6 ohms above 1kHz and reaching a minimum of 3.25 ohms just below 5kHz. The…
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In some ways, building an inexpensive yet musical two-way loudspeaker is a greater design challenge than creating a cost-no-object reference product. Although the latter is a much more complex endeavor, the venerable two-way box seems to bring out the creativity and resources of the designer. Rather than throw money at the product in the form of more expensive drivers, enclosures, or components, the designer of a low-cost two-way is forced to go back to the basics, rethink closely-held tenets, and rely on ingenuity and sheer talent to squeeze the most music from a given cost. Consequently,…
The PC80's tonal balance was fairly smooth through most of the midrange, but there was some coloration apparent in the bass as well as in the upper-midrange/treble region. Starting with the bass, it achieved remarkable extension for a cabinet of this size but tended to be underdamped and somewhat ill-defined. Bass lines were a little sluggish, creating a "rolling" sensation rather than a taut, crisp feeling. LF pitch resolution and articulation suffered, making it difficult to follow intricate bass lines. This was especially true in music in which the bass player tends to be melodic and…
Sidebar 1: Robert Harley's Review System
The Phase Technology PC80s replaced the Hales System Two Signatures in my reference system, and were auditioned on the excellent Celestion 24" spiked and lead-shot–filled stands. Each pair was driven by the VTL 225W Deluxe monoblocks, Krell KSA-250, and Threshold S/550e (the last two reviewed elsewhere in this issue) via 10" runs of AudioQuest Green Hyperlitz. The analog front end consisted of a Well-Tempered turntable, just refitted with a Lary Pederson–modified Well-Tempered Arm (footnote 1), and a Sumiko Boron cartridge. The moving-coil's low…
Sidebar 2: Mk.1 Measurements
Starting with the Listening Environment Diagnostic Recording (LEDR) on the Chesky Sampler and Test CD (JD37), the PC80s produced a good sense of the image moving up above the loudspeaker. The "over" test was better, with a clearly defined arc between and above the loudspeakers. The "lateral" test was excellent: the image was solid and moved contiguously between the PC80s. Next, I drove one loudspeaker with a variable-frequency sinewave oscillator, listened for any audible problems, and felt the cabinet for any sign of resonance modes. Not surprising in light…
Robert Harley wrote again about the PC80 in September 1991 (Vol.14 No.9):
In the January issue I reviewed the $650/pair Phase Technology PC80 loudspeakers and found them to offer good performance for their modest price. The PC80s are solidly built (1"-thick cabinet), attractive (real wood veneer), and had some special musical qualities not normally found at this price level. In particular, they had smooth tonal balance and the ability to throw a large soundstage with pinpoint images. In fact, the PC80s were one of the best-imaging speakers I'd auditioned in my listening room. My primary…
Sidebar 3: Follow-Up Measurements
Fig.1 shows the PC80's FFT-derived anechoic response, measured over a 30° lateral window with the grille on. The 2.5kHz peak is still apparent, but is lower in amplitude than that seen in my original measurement made with the grille off. This suggests, as I stated in the PC80 review, that the grilles should be left on for listening.
Fig.1 Phase Technology PC80, anechoic response on tweeter axis at 45" with grille on, averaged across 30° horizontal window and corrected for microphone response, with the complex sum of nearfield woofer and…
Lonnie Brownell reviewed the PC80 Mk.II in December 1995 (Vol.18 No.12):
Phase Technology PC80 Mk.II Compact Monitor: That's quite a mouthful (and a lot of keystrokes), so I'll refer to this as the PC80 II. RH reviewed the previous incarnation of this speaker, the PC80, in Vol.14 No.1, p.214. The tweeter is new, with a lower-mass dome material, and is mounted flush with the baffle; the crossover now features 24dB/octave slopes; the woofer magnet is 50% larger; the woofer's flat diaphragm is constructed on a Kevlar cone rather than a paper one; and the woofer now features a butyl-rubber…
Sidebar 4: Lonnie Brownell's System
Here's the cast of characters in this production: The Analog family was portrayed by Linn Axis as the 'table, Linn Basik Plus as the tonearm, and Shure V-15 Type 5MR as the cartridge. The Digital gang was played by Magnavox CDB-560 as the transport, Audio Alchemy DTI as the anti-jitter device, Audio Alchemy DITB as the converter, with Illuminati Data/Video Flex and Data Flex Studio as the cables. The staff of Control and Amplification Inc. were played by Audible Illusions 2A as the preamp, and Audio Alchemy OM-150 Overture as the power amp. Also in…
Sidebar 5: Mk.II Measurements
I did some preliminary listening to the PC80 Mk.IIs before I measured them. This is a pretty good speaker for the price: relatively neutral with a surprising amount of bass. My estimate of its B-weighted sensitivity was a little below specification at 88.2dB/2.83V/m, but this is still on the high side for a small speaker. The PC80's impedance magnitude and phase are shown in fig.1: although it drops to 5 ohms in the lower midrange and to 6 ohms or so in the high treble, it generally approximates the specified 8 ohm load. The port tuning is revealed by the "…