November 5, 2000
I'm in the midst of a minor redesign, please be patient.
In celebration of the imminent launch of Amtrak's Acela Express train, here'a .wav file of
a passby of trainset #2 at 150 mph (uncompressed mono, 1.4 MB).
I finally got around to builing some speaker stand for my DIY sat's using PVC piping. I've put up large and small pictures, I hope to have a
write-up in the next couple of days.
I also finally added a link to Bob Stout's DIY Loudspeaker Driver Selection Guide (aka the LDSG). The LDSG is an extensive
list of speaker drivers and project information (among other things) and is an invaluable resource to DIY'ers.
September 10, 2000
I finally got around to posting pictures of my DIY speaker grills (and please, no comments about the dust).
Straight from Slashdot: the Audio Spotlight, a process of
narrowly focusing sound, is being developed by the MIT Media Lab.
EDN has a nice explanation of lossy codecs used for digital audio. The article can be found here.
July 3, 2000
Well I'm off to Princeton, New Jersey for some more Acela testing. Some notable events in the meanwhile:
Lance Meister of HMMH is giving a talk at Internoise 2000 on effects of FRA's
Proposed Regulation on the Use of Locomotive Horns at Grade Crossings. His paper can
be found here (PDF format).
I'm giving a talk at the Transportation Research Board's Summer Meeting on the MBTA's experience with ballast
mats on the Old Colony commuter rail line (ballast mats are a type of rail vibration mitigation).
The DIY loudspeaker list is having a website logo contest..
Here are a couple of articles on “Quiet PC's”:
Ogg Vorbis is an open source compressed audio format, similar to MP3. Information can be found at the Ogg Vorbis website.
June 3, 2000
Lot's of quickies:
CNN has an article on hearing loss
in baby boomers.
Are you being hunted by a deranged gunman? If so, you're in luck; Norsonic is developing an
acoustic sniper detection system capable of
locating the source (and caliber!) of a gunshot within 2 seconds. Check it out.
Not to be outdone, the U.S. Army is also applying acoustical techniques to target identification in the battlefield.
The Acoustical Society of America is sponsering a student speaker design
contest. Information available at ASA's website.
The Federal Railroad Administration has released a draft spreadsheet model that predicts noise levels from railroad
horns. The spreadsheet was written by Lance Meister of HMMH and requires MS Excel.
May 14, 2000
I've been interested in acoustics for over 10 years now, and have used many, many
computer-based acoustical models and measurement equipment in that period. One thing
that has annoyed me is the lack of a standard file format for measured or modeled acoustical
data. Every software package, from MLSSA to TNM
all have there own formats.
I am proposing the development of a standard file format based on eXtensible
Markup Language (XML). You can read the original proposal here.
I have developed a first-cut DTD. You can find the DTD and specification here.
April 16, 2000
Cleaned about about 75 dead links...
April 8, 2000
One of my long-standing questions has finally been answered: Dr Colin Mercer of Prosig Ltd.
explains how the traditional octave-band center frequencies are derived.
Dr. Mercer also alerted me to some interesing articles on Prosig's News page, including
articles on FFT techniques and correlation. Check it out.
April 3, 2000
My Acela vibration presentation is now online at the HMMH
website (6 Mb, Adobe Acrobat format).
Because the DIY Loudspeakers.org page seems to be down, John E. Janowitz
has set up an alternative web-based form for signing up on the DIY loudspeaker mailing list. You can
find the form here.
March 8, 2000:
Here's a fairly good article on MP3's and sound quality
over on Arstechnica. (disclaimer: these Arstechnica guys do not
February 29, 2000:
Jonathan Smith has discussed the creation of an opensource
loudspeaker modeling tools. Towards that goal, Jonathan has started three mailing lists on
sourceforge.net. You can subscribe using web-based subscription tools:
Once the project gets rolling, a website will be hosted at http://diyab.sourceforge.net.
A recent submittal was Purebits.com, makers of PC-based acoustic measurement tools. There is a lot
of good information regarding MLS theory, as well as a downloadable trial of their flagship product. Check it out.
February 8, 2000:
I just heard that Audio magazine is no more. Heck, I still remember the days of Hi Fidelity magazine... Audio's passing
is probably not too big of deal in light of all the information available on the web. Still, it's yet one more magazine I will miss.
In other news, Greg Tocci announced at the recent Boston ASA meeting that another revision to
the Noise Criterion (NC) curves is currently being planned.
Finally, I my boss and I made the Scituate (MA) newspaper... whether or not it paints a flatting picture is for the reader to decide.
January 18, 2000:
I gave a paper last week at the Transportation Research Board conference in Washington DC.
We discussed our vibration measurements of the Acela... and yes, contrary to popular belief,
it does work.
I post some of our conclusions as soon as Amtrak/FRA releases out report, which should be in
another month or so.
In other news, I have the site submittal form working again, and everything should be up
January 5, 2000
I know lots of people are asking "what, the site has moved again??"
Well yes. You see, I have plans to grow this site over the next two or three months.
I will still keep adding new acoustics links (and trimming the dead ones) but I hope to
transform this site into something more in the weeks to come.
BTW, I have been approached several times over the last year about advertising on this site. As of
March 2000, I plan to begin running rotating banner ads, and static "block" ads on my site. If interested, please
contact me at email@example.com.
Also, the submittal form will be broken for a few days as I finish moving my scripts over to
this new site. Please be patient; if you want to submit a site before I complete the move, please
My subwoofer and satellite speaker project
My perceptual coding experience
When creating, engineering, or manufacturing a product, you have to keep the goal in mind