During my first listens after Bill departed, I discovered that the lower midrange had lost…
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After a brief listen, Bill encouraged me to try setting up the Progression M550s and Momentum HD preamp the same way they're set up at D'Agostino's Arizona factory, with the electronics resting on their attached rubber feet. I'd always preferred the effects of aftermarket supports to those rubber feet, but those that sounded best had been discontinued and returned to the distributor. I was curious to learn if returning to the rubber feet might help address some longstanding issues in my system.
Sidebar 1: Specifications
Description: Solid state class-AB mono power amplifier. Inputs: XLR. Outputs: Custom binding posts. Power: 550W into 8 ohms, 1100W into 4 ohm, 2200W into 2 ohms (all 27.4dBW). Frequency response: 1Hz–80kHz, –1dB; 20Hz–20kHz, ±0.01dB. Input impedance: 100k ohms. Output impedance: 0.1 ohm. S/N ratio: 105dB A-weighted, 75dB unweighted. (These are transposed on the manufacturer's website.) Distortion: 0.15% at 1kHz at 550W into 8 ohms. Power draw at idle: 80W.
Dimensions: 17.875" (454mm) W × 9.0" (230 mm) H × 23" (584mm) D. Weight: 115lb (52.2kg).
Finish:…
Sidebar 2: Associated Equipment
Digital sources: dCS Rossini SACD/CD transport, Rossini DAC, and Rossini Clock; Synology 5-bay 1019+ NAS, Roon Nucleus+ music server, Uptone Audio etherRegen, Small Green Computer Sonore opticalModules (2) and Deluxe opticalModule, Linksys routers (2), and Arris modem, all powered by HDPlex 300 four-component linear power supplies (3) and HDPlex 200 LPS; Apple 2017 iPad Pro and 2017 Macbook Pro laptop with 2.8 GHz Intel i7, SSD, 16GB RAM.
Preamplifier: Dan D'Agostino Momentum HD.
Power amplifiers: Wilson Audio Specialties Alexia 2 with Acoustic…
Sidebar 3: Measurements
For logistical reasons, I measured a different sample of the Dan D'Agostino Master Audio Systems Progression M550 monoblock (serial number PM006P) with my Audio Precision SYS2722 system (see the January 2008 "As We See It"). I repeated some of the measurements with the magazine's Audio Precision APx500 analyzer. Usefully, the box included a set of tests performed with the APx500.
Before I performed the testing, I preconditioned the amplifier by running it at one-eighth its specified power into 8 ohms for 30 minutes, as recommended by the Consumer…
I've got a music problem. Specifically, I've got a rock music problem.
It's a true cliché—that is, a cliché that happens to be true: Rock music, in almost all its forms, is young people's music. It's about new, fresh experiences—new love, new sex, consciousness sought or attained, rebellion, drugs—and when you've reached a certain age, those experiences don't feel so fresh anymore. That's a fact about which it's hard not to feel some regret. You don't have to share their sentiment to realize that there's a reason Pete wrote, and Roger sang, "Hope I die before I get old."
Despite…
You've got your 2001: A Space Odyssey speaker, which of course is a tall, black, featureless monolith. Then there's your wooden "Who's buried inside?" speaker, your "R-I-C-O-L-A" speaker, your enema bag or double-inverted enema bag speaker, your menacing hooded-Klansman speaker, your "looks like a robot, praying mantis, or Transformer" speaker (mine), and your "Does it leave a slime trail?" speaker (looks like a snail). You've got your "Is that a room divider?" speaker, your "looks like you stepped on a duck's head" speaker, and your "whipped cream dollop suspended in time" speaker.
That'…
Cynics, stretch a bit here: After I wrote the paragraph directly above, I found an email containing tech notes from Forza that I'd forgotten about. "The placement of woofers close to the floor assists in bass coherency and more even distribution of room standing waves. This makes it easier to find a suitable listening position in the room, with fewer compromises in bass accuracy."
When the Wilson Audio Specialties XVXes were installed here almost a year ago, Christy Moore's "So Do I" from the album This Is the Day provided a benchmark for placement. Moore's voice could sound hooded or…
Sidebar 1: Specifications
Description: Four-way, sealed-box loudspeaker. Drive-units: 1" (25mm) Accuton inverted diamond dome tweeter, 8" (203mm) CELL aluminum sandwich midwoofer, 7" (178mm) CELL ceramic membrane midrange, 2 11" (279.5mm) woofers. Crossover frequencies: N/A. Frequency range: 25Hz–60kHz. Impedance: 3 ohms (minimum 2 ohms at 42Hz and 110Hz). Sensitivity: 88dB/2.83V/m. Recommended minimum amplifier power: 20 watts.
Dimensions: 66" (1676mm) H × 24" (610mm) W × 27" (686mm) D. Weight: 330lb (150kg) each.
Finishes: White or Black Pearl Gloss, Black Matte, Dark Silver…
Sidebar 2: Associated Equipment
Analog sources: OMA K3, SAT XD-1 turntables; SAT CF1-09, CF1Ti-09, Schrìder OMA, Kuzma 4Point tonearms; HiFiction X-quisite ST, Lyra Atlas Lambda SL, Ortofon MC Century, Anna Diamond, A95, A90, Grado Epoch3, Miyajima Labs Infinity (mono), Grado Epoch (mono) cartridges.
Digital sources: dCS Vivaldi One SACD player DAC; Lynx Hilo A/D-D/A converter; Roon Nucleus server; Pure Vinyl and Vinyl Studio software.
Preamplification: darTZeel NHB-18S, Ypsilon MC-10L, MC-16L, and MC-20L and X-quisite SUT X-20 step-up transformers; Ypsilon VPS-100 phono stage,…
Sidebar 3: Measurements
As with the Wilson Chronosonic XVX that Michael Fremer reviewed in the May 2021 issue, it wasn't possible for us to maneuver one of the large, heavy Estelon Forza loudspeakers onto a dolly and wheel it into his driveway for the measurements. I therefore had to perform the measurements with the loudspeakers set up in Michael's room. The proximity of the room's boundaries meant that I performed my farfield frequency response measurements at 1m rather than my usual 50"; the goal is to push the reflections from those boundaries as far back in time as possible. The…