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BOSTON AUDIO SOCIETY MEETING
NOTICE
Date: Sunday March 25,
2018, 6PM
Place: Boston University,
Life Science & Engineering Bldg, 24 Cummington
Mall, 1st Floor Conference Room 103, Boston, MA
02215
Guest: Steve Hluchan
Topic: Optimizing High-Efficiency
Horn Loudspeakers
The project was to investigate
high-efficiency horn loudspeakers with a classic
“home” speaker as a representative example,
the Altec Model 19. We had three objectives: first
to characterize the horn and driver, both the
original Altec and a JBL equivalent. The second
objective was to optimize the configuration, including
bass driver and enclosure. Lastly we intended
to fabricate a new horn and enclosure in hardwood
and hardwood veneer. The project was not completed;
the presentation is more of an overview, with
some conclusions.
There will be refreshments
at 5:30.
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Directions:
Note that parking is no longer
allowed in the block in front of our
meeting place (temp parking for unloading/loading
is OK). There is a gap in the BU buildings
on Commonwealth Ave. so you can walk
through directly to the meeting location.
At Boston University,
Cummington St. (Mall) is an east-west
street just south of Commonwealth
Ave. It is one-way going west. From
Storrow Drive going east, take the
first BU exit. At the stop sign turn
right on Commonwealth Ave (a left
is not permitted). Bear left and at
the 3rd light take a u-turn, go half
a mile and turn right on Blandford
St.(Mall) (at a traffic light) and
turn right on Cummington St. (Mall)
The entrance is on your left, number
24.
From Commonwealth
Ave going west, after Kenmore Square,
after the tracks come up out of the
tunnel, there is a traffic light at
Blandford. You should turn left on
Blandford, but no left is permitted.
Instead turn right and make a U-turn.
Continue on Blandford and turn right
on Cummington St. The entrance is
on your left, number 24.
MBTA Green line
- exit at Kenmore Square or the next
stop, Blandford St. & Commonwealth
Ave. Walk a short distance and make
a left turn onto Blandford Mall and
then a right onto Cummington Mall.
Parking is free
on Sundays and available on Commonwealth
Ave. and Beacon St. (take a hard right
at Kendall Square and park on the
bridge and take the stairs down) and
Bay State Rd (parallel to Commonwealth
Ave next to the river)
-or-
Use your GPS (!)
—
Webmaster's note: Google maps and
Apple maps show them as Blandford
Mall and Cummington Mall.
Bing maps shows them as Blandford
Street and Cummington Street.
YMMV.
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The
BAS Message
March 2018
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1. V39N4
of the BAS Speaker has been published..It
features “On “Vacuum Tubes—Then
and Now” by Brian Geyer and CEDIA show
reports. There is a writeup of the meeting
with JansZen Electrostatics and David Janszen
by David Hadaway. David Weinberg writes
on UltraHD andHDR video.
2. Our eardrums
move in sync with our eyes
Researchers at Duke
University have been using microphones inserted
into people's ears to study how their eardrums
change during saccades – the movement
that occurs when we shift visual focus from
one place to another.. They were used the
microphones to detect changes in ear canal
pressure that were probably caused by middle-ear
muscles tugging on the eardrum.
These pressure changes
indicate that when we look left, for example,
the drum of our left ear gets pulled further
into the ear and that of our right ear gets
pushed out, before they both swing back
and forth a few times.
They may prepare our
ears to ear sound from a particular direction..
The changes to the eardrums
began as early as 10 milliseconds before
the eyes started to move.
One theory is that it
helps the brain make sense of what we see
and here.
They could imagine a
mechanism being incorporated into hearing
aids that picks up signals of eyes moving
to a new location and tries to amplify the
sound at that location..
[I wonder if tensioning
the eardrum raises its resonant frequency
and thus enhances the sensitivity to high
frequency pitches which are important in
sensing directionality] New Scientist 29Jl17.
email me here
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| Below,
other meetings and notices which may be of interest
to BAS members |
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| BAS
MICROPHONE CLINIC REPORT ! |
| In September
2009 the B A S held a microphone clinic, testing 37 different
microphone models. The ambitious nature of the clinic
effort, the extent of data collection, the number of individuals
involved in microphone testing and in writing various
sections of the report, and the complexity in determining
how to construct the clinic report and make it available
to members resulted it not being published until now.
The dataset is extensive.
Representative samples were included
in the abbreviated report in "The B A S Speaker"
(Fall 2015; v37n3)
Go to the MICROPHONE
CLINIC PAGE for more...
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When collecting
and plotting "noisy" data it is
often useful to have Microsoft Excel plot
a Trend Line through it. If that data
is to be used for further work, it may be
necessary to have an X-Y table of the Trend
Line. That is not easy to get and this paper
will show how to do it.
Joseph DeMarinis
has a new article here: Extracting
Numerical Data from an Excel Trend Line
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Foster's
Test Bench !
by Alvin Foster ! Click
the logo: —> |
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The rapidly-becoming-famous
BAS Headphone Test Article is now
available in the BASS VOLUME 25, ISSUE
4, on Page 17, available HERE
PDF 3mb |
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Visit
our PODCAST PAGE
for:
The LIVE video podcast of our meetings,
Archived video of past meetings (only one
so far!),
and Audio Podcast interviews by Alvin Foster |
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There is a supplemental and
further explanation addendum paper to the E. Brad
Meyer / David Moran paper published in the September,
2007 issue of the AES Journal. That
page, which documents the experimental protocol
and audio systems/source material is here:
www.bostonaudiosociety.org/explanation.htm
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| There is
a Power Point Presentation of the lecture given
by Dr. Barry Blesser at the March 2007 Meeting.
The Meeting page synopsis is HERE;
the Power Point Presentation (as a web page) is
HERE |
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Some earlier
BASS issues, previously available only
directly by mail, are now available online, on
the BAS SPEAKER page, HERE
Show your
appreciation for the immense amount of dedicated
work that went into both the original writing,
gathering, editing and printing, PLUS the
more recent scanning and conversion to PDF format,
by joining the Society, HERE
!
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A
L L O F F S I T E L I N K S O
P E N I N T O A N E W
W I N D O W
- AND FOR CONVENIENCE
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The Boston Audio Society needs
individuals who will write summaries of BAS meetings into *.pages,
*.doc, or *.txt files. We usually have audio recordings of the meetings.
We pay for your work. Ask about our bonus program for meeting-writers!
Contact David B. Hadaway (603-899-5121; dbsys22@att.biz).
Does anyone have a schematic (or any other
info!) for any Dunlop-Clarke Dreadnaught amplifier? Email Barry
at webmaster@bostonaudiosociety.org
For sale: Audio Precision System
1 audio test system. SYS-322A, s/n SYS1-31968, IMD, BUR, W&F
options, A-weighting filter, PCI interface card, rackmounts; asking
$5000. Contact Mark Chambers machambers@charter.net
For sale: Several CD storage
racks, some made by Bostonwood (www.BostonWood.com/cd.html):
Two four-shelf units (25.5"Hx17"Wx5.5"D); One four-shelf
unit (25.5"Hx24"Wx5.5"D); Two three-shelf units (19.5"Hx17"Wx6.5"D);
one home-made three-shelf unit (18"Hx14"Wx6"D). I
have attached a handle and chains to several units, making them
convenient open-top carriers. David J. Weinberg (Maryland; 301-593-3230).
Seeking a two-channel preamplifier
such as an Apt Holman, an early Hafler, or an early NAD. Must work
properly. Fred Ampel (FAmpel@KC.RR.com).
Seeking prereceord Advent cassettes,
especially Russell Sherman Beethoven and Liszt recordings, and Handel's
Messiah performed by the Handel & Haydn Society under Thomas
Dunn. David R. Moran (DRMoran@aol.com).
I am disposing of all my old copies of
the BAS Speaker, which go back to 1978, more or less complete. I
am going to recycle these with waste paper unless somebody wants
them for free. I'll even pay shipping. Doug Pomeroy Audio Restoration
& Mastering Services audiofixer@verizon.net
Discography of Test Records.
I am compiling a list of technical test records from all recording
eras and would like to exchange information in order to confirm,
expand, correct and add entries. Send me your list and/or other
information about test records and I will send you my discography,
which has nearly 200 entries to date. I am interested in commercially
released records, as well as discs intended primarily for in-house
use by audio engineers, broadcasters and for other special applications.
I am generally excluding demonstration discs of the "Super
Stereo bouncing ping-pong ball" type unless they include at
least some tracks of a technical nature, such as frequency response
and tracking tests, etc. Nicholas Starin, Portland Oregon, NTSTestDisc@Gmail.com.
Nashville AES Test CD. (www.AESNashville.org;
click the small round symbol where it says "Click here for
more info:" to download the four-page description and track
list. Use the link on the website under <Products> to send
an email for pricing and availability.) From the website: "Assembled
'by engineers, for engineers' after a survey of the needs of a broad
cross-section of working audio pros, the disc features 71 tracks
of test signals ranging from level calibration tones, noise signals,
third-octave tones, polarity and digital meter calibration pulses,
bandpassed noise and swept sinewaves. Additional tracks include
dry-recorded kick and snare drums, acoustic guitar and piano along
with spoken word and a cappella male and female vocals. A data area
on the disc features BPM charts, Excel-based calculators and other
bonus material. The CD booklet includes tutorial information on
using the test disc."
For sale: Three Denon DR-M34HR
cassette decks ($500srp) with three heads and live monitoring of
the recording, dual Dolby B/C and Dolby HX Pro circuitry. Handles
normal, chrome and metal-tape cassettes. Highly regarded in 1988.
Gasparo Records used them as duplicators. In good shape. Data at
www.VintageCassette.com/denon/dr-m34hr.
$125 ea+shipping. Contact David B. Hadaway. dbsys22@att.biz.
For sale: Arcam Solo Movie 5.1
(www.Arcam.co.uk/products,solo,Movie-Systems,SoloMovie51.htm;
$4500srp) The manual is downloadable from the Arcam website. I do
not have original packaging. $1000+shipping, which will be calculated
once destination is determined. Funds transfer or cash only; no
checks. Fred Ampel (FAmpel@KC.RR.com).
For sale. Two Tannoy HPD 315
speakers, made in the mid-1970s, woofers might need refoaming. Steven
Weiner (SDWeiner@ATT.net;
818-865-0601; Thousand Oaks, CA) is asking $500+s/h. [I have seen
a photo; the cabinets and grill look to be close to mint condition.
This ad was placed at the request of member Randy Hoffner. DJW]
Seeking: Soundfield Mark IV
microphone. Jim Mastracco (James.Mastracco@Verizon.net).
Laserdiscs for sale by David
J. Weinberg (301-593-3230; WeinbergDJ@BostonAudioSociety.org)
Four have Dolby Digital 5.1 soundtrack. Nine have DTS5.1 soundtrack.
Make offer for all or selected items.
| TITLE |
CLV / CAV? |
ASPECT
RATIO |
| Video Essentials |
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| Apocalypse Now |
CLV |
2 |
| Apollo 13 |
CLV |
2.35 |
| Batman (Michael
Keaton) |
CLV |
1.78 |
| Blade Runner
(Director's Cut) |
CAV |
2.48 |
| Blown Away |
CLV/CAV |
2.35 |
| Crimson Tide |
CLV |
2.35 |
| Daylight |
CLV |
1.85 |
| Evita |
CLV |
2.35 |
| Forbidden Planet |
CAV |
2.35 |
| Golden Eye |
CLV/CAV |
2.35 |
| The Grifters |
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| Highlander (10th
Anniversary Director's Cut) |
CLV/CAV |
1.82 |
| The Hunt for
Red October |
CLV |
2.35 |
| In The Mouth
Of Madness |
CLV |
2.35 |
| Jurassic Park |
CLV |
1.85 |
| Jurassic Park |
CAV |
1.85 |
| Phenomenon |
CLV |
2.35 |
| Pocahontas |
CLV |
1.66 |
| Pretty Woman |
CLV |
1.85 |
| Raiders of the
Lost Ark |
CLV |
2.35 |
| Raiders of the
Lost Ark |
CAV |
1.33 |
| Star Wars: Episode
1 - A Phantom Menace |
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| Toy Story |
CLV |
1.78 |
| Who Framed Roger
Rabbit |
CLV |
1.75 |
Own a movie theater sound system! For
sale, top-of-the-line High Performance Stereo HPS-4000-XL screen
speaker systems. Three (left, center, right) HPS model 545-4 speaker
systems (www.HPS4000.com/pages/fivefortyfive_.html)
and two HPS model 545-W subwoofer speaker systems (www.HPS4000.com/pages/545_w_.html).
All in perfect working order. The speakers are not light, but consist
of modules that can be lifted by two moderately strong men. Truck
delivery only, or come pick up. Make me an offer. David J. Weinberg
(301-593-3230; WeinbergDJ@BostonAudioSociety.org):
Most units come with user manuals (some
also with service manuals), remotes and cartons, as applicable.
Make offer:
- ReplayTV 2020 with aftermarket larger
disk drive. Includes lifetime electronic program guide service.
- Faroudja VP400A video quadrupler.
Upscales NTSC video to 960 progressively scanned lines for a front
or rear CRT projector. Generates great image on my big screen.
I don't need it because I'm modifying my video system.
- Runco 980Ultra CRT projector (original
packing, user and service manuals).
- Vutec concave high-gain silvered screen.
8' wide, 16:9 aspect ratio, with wallmount brackets. Silvered
surface makes it appropriate for 3D projection, as the high gain
overcomes the substantial light loss caused by the various consumer
3D projection technologies, and the curved shape can deliver a
wide viewing angle with little hotspotting.
- Lexicon DC1 surround processor, with
all options.
- Panasonic RP-91D DVD player with JVB
Digital regionfree mod.
- Sony DVP-NS755V SACD (multichannel
and stereo), DVD, etc., progressive-scan output. $250srp.
- Tektronix D11 rackmount single-beam
storage oscilloscope with 5A15N vertical amp and 5B10N time-base/amplifier.
- Tektronix 5111 rackmount single-beam
storage oscilloscope with two 5A18 vertical amps and 5B10N time-base/amplifier.
- Teac AN-180 external dual Dolby B processor.
Simultaneous stereo record and playback.
- Pioneer CT-F4242 cassette deck, in
excellent condition.
- Garrard RC88 turntable with Shure M3D
cartridge, in excellent condition.
- Sony XM-5046 car audio amp, 4x50W into
4 Ohms
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