Audiophobe

Two of my Friday Lunch companions play guitar -- one acoustic and one electric. Guitar pickups, amps, and other things luthier-ish come up in our free-ranging discussions over British ales and bangers and mashed or margaritas and molé. I found this fun 2014 BBC documentary on Marshall Amps -- Play It Loud: The Story of Marshall Amplifiers  -- yes, some go up to eleven, but no further spoilers here; watch it yourself.  I noticed that Marshall were using KT-88 "valves," which are similar to the 6550 I used in the 25W bootleg AM transmitter I built in 10th grade.  KT-88s are also in the 75W McIntosh amp I rescued from the dumpster when SRI's Sound and Vibration lab was being shut down.  My mom's old tube amp used 6V6GTs and the PA amp my Uncle Norman used for Bingo Night at their shul used 6L6GTs.  All these are beam power tetrodes... so are the Eimac 4CX250B and 4CX5000A used in WRPI's old FM transmitters. Poking around for info on the KT-88...

Last Friday at lunch, I was telling the well-known---and very San Francisco centric---story of Jack Mullin and the WWII origins of high-fidelity magnetic tape recording.  One account of the events is here: https://www.vox.com/2016/5/16/11672678/tape-recording-70th-anniversary-jack-mullin My only quibbles with this account are  it claims that we don't know the identity of the German engineers who developed the Magnetophon,  frequently refers to the use of wax recordings for radio transcription, omits the fact that Crosby wrote a no-strings-attached check to Ampex for $50K (over $600K in 2022) that allowed them to purchase the parts and set up production of the first 24 Model 200 machines.  Ampex, in return, appointed Bing Crosby Enterprises (BCE) to be the US distributor of their products west of the Mississippi.  The first is simply wrong, the key innovator was Walter Weber at Reichs-Rundfunk Gesellschaft (RRG).  RRG commissioned AEG to build the machines f...

Eric Benjamin and I had a paper accepted for AES 153 (NYC, 10/2022), but we decided to withdraw it because between the "Presenting Author's Fee" and online conference registration fees, it would cost over $400 for us to present it. Here's Eric's note to the program committee:  My colleague, Aaron Heller, and I would like to withdraw our contribution to the 153rd AES Convention. Our reasons are multiple but primarily it comes down to cost.   I’ve been contributing articles to AES conventions and to the journal for more than forty years. During that time, I have seen the support provided by AES to the authors dwindle. Twenty years or more ago, convention registration fees were completely waived for authors. In the intervening years, that support has been reduced. For our paper in the Spring 2021 convention, the presenting author’s fee was $139; now a year and half later I have received a bill for $320 to present our current paper. The work discussed in these papers ...

I'm please to announce that "Optimized Decoders for Mixed-Order Ambisonics" by myself, Eric Benjamin and Fernando Lopez-Lezcano, presented at the 150th AES Convention (May 2021), is now available on  arXiv . If you want the version with the AES logo and boilerplate, you can purchase it from  AES E-lib . Here's the abstract: In this paper we discuss the motivation, design, and analysis of ambisonic decoders for systems where the vertical order is less than the horizontal order, known as mixed-order Ambisonic systems. This can be due to the use of microphone arrays that emphasize horizontal spatial resolution or speaker arrays that provide sparser coverage vertically. First, we review Ambisonic reproduction criteria, as defined by Gerzon, and summarize recent results on the relative perceptual importance of the various criteria. Then we show that using full-order decoders with mixed-order program material results in poorer performance than with a properly designed mixed...