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Welcome to the Bass Pig's Lair!
2nd Annual B.A.S.S. Meetup
Recap:
As with last year, our B.A.S.S. Meet was a
great success!
Thank you to all who attended and brought so many great food items as well!
The main audio/video demo featured my Blu-ray productions of the Bridgeport
Symphony Orchestra with Alex Beyer, performing Rachmaninoff's Piano Concerto No
3 in D minor, then the GBS performing Rachmaninoff's Symphony No 2 in E minor,
(selected movements), then Allison Eldredge with the Boston Classical Orchestra,
performing Saint-saens Concerto for Violoncello in A minor, then the Zambelli
Ultimate Fireworks Blu-ray that I had the pleasure to capture from the launch
pad, then I played a track from a Japanese soundtrack "The Weathering Continent"
as a 2-channel Sonic Holography demo. Next up was a demonstration of the dbx 500
Subharmonic Synthesizer. For this demo, I used appropriate material lacking in
fundamental bass (Average White Band "Pick Up the Pieces") and then gave an
example of the absurd Bass Pig effect when you use it with Reggae music that
DOES have some bass.
We took a break at the buffet and then returned to the Lab portion of the day
where I demonstrated Bell Labs' new tri-tone test for Transient Intermodulation
Distortion. We tested a Sansui AU-9500 against a Lepai 2020 amplifier. The
results were colorful and interesting. The test setup consisted of three
Tektronix SG5010 precision audio oscillators, outputting 10.05KHz, 9KHz and
20KHz, respectively, summed into a resistor network which fed each of the audio
amps under test. I also performed traditional THD and SMPTE/DIN IMD testing. The
Sansui easily tromped the Lepai on traditional tests, with ultra-low .028% THD,
but the tables were turned when the tri-tone tests were performed, with the
Lepai being an order of magnitude lower in TIM distortion than the Sansui.
And finally, I fired up the HP 8568B spectrum analyzer, connected to an outdoor
antenna, and displayed the spectral mask of several FM stations, some with and
without IBOC (In Band On Channel) or HD Radio digital transmission, discussing
the effects on DX listening with the presence of the wider digital sidebands.
Our last guest showed a BD of Baraka on our big screen, which provided a
colorful and sometimes disturbing look at life around the world, focused mainly
around Asia.
All in all, a positive experience, many questions and positive comments.
Hear Ye, Hear Ye! Announcing the
FIRST EVER Basspig
Audiophile
Society
Social
(B.A.S.S.)!
The first annual B.A.S.S. Meetup was a smash success! 7
attendees, from as far away as Pennsylvania (actually two) and the rest hailing
from the tri-state area.
A great time was had by all, plenty of food was consumed and it was like a
mini-fest, complete with laboratory demonstrations, fine music, the Ultimate
Fireworks (my neighbors started lighting their own fireworks after mine were
done, as they must have thought I had a lot of illegal explosives here),
showings of reference footage shot on the Samurai + CineAlta cameras and a MIDI
demonstration. Several guests suggested we do this again next year and that they
would love to do it again. My lasagna was a hit, and some of the guests brought
everything from wine to rum cake and chips. We even had the editor of
Stereophile Magazine in attendance, which was a rare surprise. In all, it was
worth the effort and I know I had a great time, and I think everyone else did
too.
I have to say that the level of quality of the people I met this evening served
to boost my faith in humanity. I met some very decent folks this evening! Thank
you all for coming!
One of my guests, and a good
personal friend, Dr. V, wrote an interesting blog post about his visit to the
Lair. You can read it
HERE.
A Look Behind the Scenes
The Bass Pig's electronics laboratory. Here is where I design, build, modify,
and repair audio equipment. There's too much to list (I get a case of "Crow
Epistemology" when I try to recall all the model numbers), but the highlights
are the Tektronix AA-501 Distortion Analyzer and the HP 3585A Spectrum Analyzer,
which are two important tools that I use for analyzing the performance of audio
and RF amplifiers. I have an assortment of function generators, ultra low
distortion oscillators, power supplies, digital multimeters, temperature probes,
and a Tektronix 576 Curve Tracer. That last item is my tool of choice for
testing vacuum tubes. I have also found it useful, with a pair of probes, for
troubleshooting in-circuit components. Electronics has been my profession for
over forty years.
Phase Linear D-500 Hum
Reduction Modification - $750 I'm now officially
making my D-500 modification service available to the audiophile community,
after many requests. I've refined the modifications and added a few tweaks to
make the amp topology more stable. On top of that, I tune the amp on a spectrum
analyzer for lowest distortion. I've
written about this modification on my own D-500 a few years back. You can
find out what it entails. The purpose is to fix some wiring topology problems
that prevent this otherwise amazing amplifier from reaching its full musical
potential. If your D-500 suffers from hum and buzz (especially from light
dimmers) and the problem is more severe in the left channel, then my
modification will eliminate the interference. In addition, I replace any aging
capacitors, particularly the one in the low voltage control board PCB assembly,
which is known to fail often. The D-500 is also a bit unstable and tends to
oscillate ultrasonically, especially if driven to clipping. I add parasitic
filter capacitors to the B+/- busses to prevent this condition, which could
damage your speakers, if severe enough. Enough people have begged me to offer
this service, so here it is. Contact me at
basspig@(this
domain name basspig.com)
to make arrangements. If you live in the northeast, walk in drop off pickup is
often the best and safest way to deliver your D-500.
Bass Pig's
$2500 Projection Screen
Construction Update
I built a projection
system/theater for only $2500 in total expenses, including screen, projector
(purchased on eBay), fabrics, wood framing and three chairs. See the results:
As of 8/14/2009--finally, done hanging
curtains:
See it in action:
Equipment racks are divided into signal
sources and power amps/speaker management:
The analog equalizers are no longer in use, due
to my tighter restrictions on noise floor of devices in the External Processor
Loop. I am solely using the DEQ2496 for this purpose, as it contributes less
hiss to the overall chain.
For more photos and to see photos that
have been moved from the front page, go to the More Photos section and select
2009 photos.
Square Wave Response
Test
Recently, I became curious about
reproducing square waves, acoustically. I knew that this is generally an
exercise in futility, given that there are so many factors ranging from driver
alignment, phase rotation vs. frequency, room reflections/acoustics and even
audio electronics, particularly audio player DACs.
My first step was to find a good square
wave source. My Oppo BDP-83 failed miserably at that, producing a generally
square-shaped wave with higher frequency sine waves riding on top, decaying to
near zero by the zero crossing of the fundamental wave. I ended up using a high
quality DAC that I use for recording professionally, to produce a decent enough
square wave. That was fed through a mixing desk and 40' of cheap coax to the
Carver C4000. This is the output of the C4000 (top trace). Bottom trace is what
a Behringer ECM8000 omnidirectional measuring mic picked up in the center seat
of the front row. Needless to say, it wasn't as bad as expected. It indicates
that room reflections are well controlled, even from the live (rear) end of the
studio. From a listener standpoint, it was always apparent that the system
presents excellent transient response, but I like to confirm what I hear with
measurements.
500Hz in room square wave response measurement at listener position.
About Planning of Bass Pig's New Projection
Screen
The
plan denotes a 'false wall' which supports a new perforated screen material from
Seymour AV, which is highly-rated for audio transparency and visual performance.
The frame supports a sub-frame with the screen, which is secured by deadbolts
for easy removal for cleaning and maintenance and is
tilted down slightly to maintain perfect alignment with the projector's image
plane, which has a fixed 36% offset. I purchased an InFocus IN82 projector,
which provides 1920x1080 native HD resolution.
Theater enthusiasts will notice that the screen is a
2.35:1 aspect ratio. The new screen and false wall completely conceals my not-so-pretty array
of speakers, and finalizes my 25-year dream of turning this into a theater. Why
did I wait so long? Because until last week, I did not see a projection system
that would rival direct-view plasma screens. What I saw at a friend's house in
July 2009 (I went there to help him calibrate his projector and achieve dark, inky
blacks with great success) totally changed my perception of projection
technology. This new DLP stuff has contrast ratios that exceed my LCD TV screen
by 5:1! I was seeing deeper blacks on the big screen than I saw on my LCD.
Hence, a milestone was reached. So I immediately researched projectors, found
one with even better shadow detail, based on screen shots and reviewer comments,
and looked on eBay and lo and behold, I snagged a $5,400 projector for $1,425
open box with 76 hours on it! I immediately went to work on designing a screen
and making a materials list.
So here is what the final concept
is expected to look like. I expect to be able to use a lightweight velvet
material for the drapes, in as dark a burgundy red as I can find.
The projection (active) area of the screen
is 12 feet wide by 5 feet high.
A pixel of 1920x1080 will be 0.043", or about the size of the period on a
typewriter keyboard. After seeing my XDCam footage from a Blu-ray disc that I
authored on my friend's projection system, I developed a new respect for the
CineAlta line of cameras!
an
Exclusive Tour of Bass Pig's Lair in HD (2008):
PHILOSOPHY -- To prove that LOUD and HI-FIDELITY are not
mutually-exclusive.
(While defining a whole new set of terms, starting with "sonic violence.")
FRONT MAIN SPEAKERS... Six E-V EVX-180Bs and four Bassmaxx ZR-18s (June 2006)
It may not look like much, but thanks to long-stroke, it displaces over
8,000 cu in of air.
[October 2009, Update]
So
much has changed here since my last writing. The addition of a
screen and projector arose out of a visit to a friend's home
theater, to tweak the colors on his new projector. I was a skeptic
on projectors for years, as none of what I'd seen 'til recently was
even close to a cinematic experience. I came away from that session,
forever a changed man!
So
the changes you see here are a direct result of my experience of
July 2009. I finally decided that the technology had reached the
milestone where I was willing to invest. A series of events fell
together so easily, that it could almost be said that "divine
intervention" wanted this theater project to happen. The appearance
of a very expensive projector on eBay, at the right time, and at an
unbelievably low bid price due to a lack of bidders, the help I
received from family and the speed and smoothness with which I
planned the construction, all made this a reality in just three
weeks.
What
I'm writing about in this column is about the audio side of things.
Given that I was erecting a semi-permanent screen wall, I wanted to
address some acoustic treatment issues once and for all, which I had
been procrastinating on for more than 25 years. I bought many boxes
of acoustic fiberglass panels and finished the treatment of the wall
behind the speakers. The screen arrangement begged for a tighter
speaker arrangement. With the LCD panel removed, I could populate
that space with the mid-bass cabinets. (I had tested the effect of
putting one double 18" cabinet in that central position about 15
years ago and the result was a visceral increase in bass.) Recalling
past experience, I knew there would be some benefits to having all
the woofers close-coupled.
Getting all the cabinets down to a sixteen foot-wide footprint
proved to be very beneficial. The former arrangement with the four
foot gap in the center was inefficient because it created a
situation where the woofers acted as two separate sound sources,
introducing cancellations of low frequency energy down the center.
Moving them all together created a unified sound source, eliminated
the cancellations and also gave the benefit of mutual coupling,
making the whole cluster act like one sixteen foot woofer. At a
given reference power level, the increase in SPL was about 6dB, just
from moving the cabinets together to form one unified source!
The
biggest challenge to deal with is that the seating is located dead
middle of the room's length. Since the room acts as a waveguide,
it's apparent that 2X the wavelength of the room will be the
frequency at which the back wall's reflected wave will cancel the
front incidental wave. That frequency is 36Hz in the center of this room. The dip
was especially deep and narrow, in this case. I later discovered
that the dividing wall between this room and the next was resonant
at... you guessed it--36Hz! I mass-loaded it with concrete panels
from the other side, and added a 4x6" brace in the middle, to bring
the resonance up to 55Hz. Lo and behold, the dip at 36Hz is not
nearly as deep and not so narrow anymore.
The
next step to solve the reflected energy is to add plywood resonant
panels to the back wall. These panels will be tuned to 36Hz and
their function will be to absorb only that frequency so that it
won't be reflected back to the center of the room where it causes
cancellation. I've already built some bass traps, and a friend of
mine donated a couple of bass traps that his
company manufactures.
Acoustically, the room sounds quite neutral now. If Bob Carver could
hear this!
