david@uwm.UUCP (David Robinson) (03/05/91)
The following article is from POSITIVE FEEDBACK, the newsletter of the
Oregon Triode Society, and is Copyright 1991, all rights reserved. This
article may be reposted or reprinted, as long as it is not resold, and as
long as proper attribution of the source is made in full. Please keep
this header in all copies made of this article.
David W. Robinson
Editor, POSITIVE FEEDBACK
david@agora.rain.com
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NOTES FROM THE SHADED DOGHOUSE
Ian Joel
Ye Editor hath requested a review of the staff reference systems in-house
(where else?), along with anecdotal background information, listening
biases, etc. A juicy assignment that ought to warm the heart of the most
callous audiophile (those of us in the pursuit of aural happiness or, as
Anthony Cordesman puts it, "the sport of audio").
Naturally, my prime reference is the sound of live music played acoustically
without any amplification (NO P.A., please). I've been involved as a banjo
player with bluegrass bands for over 20 years. The banjo is somewhat unique
amongst acoustic instruments in its tonal adjustability. By changing the
tension of the banjo drum-head you affect the harmonic structure of the
instrument; e.g., tightening the head produces a brighter sounding banjo.
The banjo also has an adjustable tailpiece that affects the amount of
tension created on the bridge by the strings. The greater the angle between
the top of the bridge and the tailpiece, the greater the force exerted upon
the bridge, which also has an effect on the tonality. All stringed
instruments are sensitive to the gauge and composition of their strings plus
the material and design characteristics of the bridge.
Quite a few user-adjustable features you say? Humm...not all that different
from adjusting the VTA of a cartridge or its tracking weight (tension)....
As you may have guessed, I'm firmly rooted in the user involvement camp of
audio. You can easily see the genesis of my audiophile urges (gotta have
Tweaky cereal in the morning).
LET'S TALK ABOUT HARDWARE
Having lived with a 1963 pair of Quad ESL speakers for the better part of a
decade I certainly respect their sonic strengths: Transparency, tonal
neutrality, especially in the human vocal range, and above all a coherent
presentation of the musical event. I'm also aware of some of their
weaknesses: Limited dynamic range, some roll-off of high frequencies,
limited low frequency extension, beaminess, and--the final straw for many--
sensitivity to room placement. We moved to a household where the Quads
wouldn't fit, so (with some remorse) I replaced them and began a journey
into the wonderful world of mini-monitors.
My current speakers are Pyramid Metronome 7s, designed by Dick Sequerra and
1982. These are true mini-monitors that measure approximately five inches
wide by seven inches high by ten inches deep, are time-aligned, and feature
a 1.5" treated paper cone tweeter with 4.5" woofer (miniature pinscher
sized). They are secured in lead shot-filled, fully adjustable metal
stands, 30" above the floor. The Met 7s image like crazy, disappear into a
wall to wall panorama of sound, have great depth of field, are surprisingly
neutral, and can be enjoyed off axis, or even standing!!
Did I say that I'm on a self-imposed budget? You'll begin to see how much
fun assembling a system on a budget can be. The trick is to buy used high-
end equipment that has 1) passed the greatest point of depreciation, and 2)
has passed the test of time. The latter is the key to used high-end
component selection. How many reviewers have changed their minds after
writing a glowing review of the latest hot item? It seems that we only
learn of reliability or sonic problems years later.
The Met 7s sold for $275.00 a pair in 1982! They were a bargain then and a
steal today on the used market. Dynamic range is a weakness; if you spend
most of your listening time on large orchestral works, then these (and most
mini-monitors) just wouldn't satisfy.
Gradually, the lack of bass output and extension began to bother me, so a
number of subwoofers were auditioned. Eventually, Charles Wiens, another
OTS member, designed a neat little twelve inch wide by thirteen inch high by
sixteen inch deep passive subwoofer with an eight inch dual coil driver that
crosses over at 60 Hz and allows the satellites to run full range, retaining
their strengths. The choices of active or passive crossover, crossover
points, amplification, etc., have led to many an unhappy camper. My system
is perhaps the simplest: One subwoofer powered by the same amp as the Met
7 speakers. This allows for the cohesiveness of one power amplifier's sonic
characteristics.
"Golden age" amplification is provided by a Harmon Kardon Citation II, circa
1963, 60 watts of Class A tube power. This amp has a little less detail
than most of the current high end amplifiers that I've auditioned, but it
has a quality in the midrange that makes a lot of (musical) sense. Did I
tell you that the Citation is connected to the Met 7s by MIT Music Hose and
a short run of Audioquest BC 4 to the Wiens subwoofer?
Preamplification involves two routes: The phono signal is amplified (or is
it preamplified?) by a highly modified Dyna Pas 3. The high level signals
are passively regulated through the Dyna's stepped Alps pot. Fellow OTS
member Alan Garren did the bulk of the modification work a few years ago.
The Dyna really isn't a Dyna (can you get anything finer in Carolina?)
anymore. Same chassis, transformer, and faceplace--that's about it. There
are no tone controls, mode selector or balance control; in short, a full-
tilt hot rod.
The "Garren preamp" has acquitted itself admirably in comparative listening
sessions involving other current tube preamps retailing in the $1,000-$1,500
range. However, I do plan on making further upgrades very soon, and will
keep you advised. By the way: Interconnection between the preamp and amp
are a pair of Alternative Audio interconnects, designed by Dave Herren.
These list for $120 per four foot pair, and are the best that I've
auditioned in their price range.
Two music sources dominate my listening habits...FM and LP. "Wipe that smile
off your face, mon!" Sure, I have a Revox A77 reel-to-reel tapedeck, a
cassette tapedeck, and (shudder!) a CD player, but "When the going gets
tough, the tough listen to LP," says G. Gordon Liddy, me likes to think.
Serious sounds for serious folks...
A Sota turntable with Sumiko "The Arm" fitted with a Joseph Grado signature
model MCZ cartridge terminated to a Premier PIB-1 interface box are
connected to the preamp by Straight Wire LSI. When this set up was new in
1982, it was close to "state of the art," and guess what? It still can
extract most of the musical content imbued in an LP.
For the Lazy (do I see any hands raised--besides mine?), FM radio fills the
working hours with a wealth of pleasure. An unending variety of programming
material fill the air waves. I must confess that 99.9% of my FM listening
is spread between four stations, all conveniently located at the lower end
of the dial on my Dyna (solid state) FM6. Straight Wire LSI interconnects
the FM6 to the passive high-level section of the preamp.
THE ROOM
The listening room acoustic is probably the single greatest wild card in the
sonic equation. Our living room is fourteen feet wide by seventeen feet
long, with a nine foot high rounded arch ceiling that flows gracefully into
the side walls. You enter the living room through a seven foot by seven
foot open entrance that's adjacent to the main hallway leading upstairs, and
to the kitchen. There's a small open fireplace that abuts at a 45 degree
angle from the long wall to the entrance. The other long wall houses a
large nine foot by five foot three piece window frame overlooking the street
below. Directly across from the window is a six foot by seven foot 1905
vintage sliding door that's an entrance to the dining room.
The Met 7s are placed four feet from the side walls and four feet, eight
inches in front of the back wall, leaving six feet between the speakers.
The subwoofer is situated directly between the speakers. The back wall is
lined with book shelves and two large wooden storage cabinets, housing six
and eight drawers full of records. The turntable, preamp, and tuner sit on
top of one cabinet, while the amp resides on the floor below.
A four person couch seats the listener nine feet from the speakers, with his
or her ears approximately parallel to the tweaters. The general consensus
about the room has been favorable. Using the Stereophile test CD with a
Radio Shack sound pressure meter indicates a smooth frequency response
between 200 Hz and 31.5 Hz (-4db point) with a possible room-induced boost
at 80 Hz and 63 Hz (+6db). the reason that I'm speculating about the room
influence is the measurements (with similar boost) were recorded while
auditioning a pair of Apogee Stages recently. (By the way: It's pretty
enlightening to observe the frequency response fluctuations while moving the
meter around the room.
THE SOFTWARE
I listen to a large variety of recordings during equipment evaluations, but
must agree with J. Gordon Holt's edict not to listen more than once a month
to music that you cherish. With that warning in mind, here's a short list
of favorite test records:
Getz/Gilberto, Verve V6-8545, recorded in 1963--this is a real sleeper
commonly seen in the bargain bins. A lush recording that characterizes the
tube sound of the early '60s. Stan Getz is a tremendous stylist and his
work here is classic. We often use the first cut on side one, "The Girl
>From Ipanema" during listening sessions. Note Astrud Gilberto (Joao's wife)
singing here...
The Seldom Scene Live at the Cellar Door, Rebel SLP 1547/48, recorded live
in 1974 and probably out of print--is another good one. The Seldom Scene
are a fine modern style bluegrass band from Washington D.C. with world-class
musicians. The recording reaches out and captures both the audience and
club ambience. Listen to Steve Goodman's "City of New Orleans" followed by
"Grandfather's Clock."
Cantate Domino, Proprius Prop 7762, recorded in 1976 in Sweden with
audiophile intentions--a good test of a system's ability to reproduce the
human voice, hall ambience and bass response. (My system fails on the third
test; on Editor Robinson's system, the low pedal notes literally shake the
floor!)
TO SUMMARIZE
My system is comfortable to live with. It presents a cohesive image of the
musical event without drawing the listener's attention to system problems.
It passes the most stringent test of all: Useability, bringing hours of
pleasure every night. Our audio hobby demands at least as much...never
less.