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Posts from the ‘Sound’ Category

Sound Reinforcement

February 7, 2015


The group at Carnegie Mellon’s WRCT radio station not only recorded classical music and produced Scotch and Soda records but also did live sound for concerts. The concert pictured was at Chatham College in 1972. Brian Rosen, who also mixed about a third of the famous Woodstock concert, headed up the sound reinforcement crew. He also worked for the CMU Computer Science engineering lab where we designed and built our mixing boards and power amplifiers. The board shown below was hand laid out with black crepe tape and then photographed and photo-etched in house and then hand soldered. Each of the nine modules was interconnected with a ribbon cable. The resulting twelve channel stereo board was only 3 inches deep and 19 inches high by 32 inches wide. The eight foot speaker columns were built in two sections, the bottom section having wheels. Each column was topped with a commercial horn speaker. The whole system was powered by four – hundred watt lunchbox amplifiers.

2015 02 07 blog 1972 05 00 00 Chatham PVW BSR2015 02 07 blog 1972 04 00 00 PVW

Scotch and Soda

February 6, 2015


Scotch and Soda is the amateur theater group at Carnegie Mellon University. In the 1970s the group would produce one full length original musical each year. Each Spring the group would take over the Skibo ballroom and transform it into a theater. The stage was stored under the football stadium and had to hand carried in sections and rebuilt each year. WRCT and later our studio would provide sound reinforcement and a records (vinyl recording) of the production. The color photo shows Joel Wolensky recording the tracks for a recording of the show “A New Day” in the Fine Arts studio. Since the studio was located two floors above Exhibition hall he was linked using video. That’s a Crown of Elkhart two track recorder directly to his right. The six rack recorder and its electronics are to his far right. The black and white photo was taken in the Skibo ballroom as we recorded the band and chorus for the show “Festival” again using the six track recorder seen to the far right. The band is to the left out of the picture. The Sony recorder and the board to the far left were used for a simultaneous stereo mix.

As most of you know by now the Emlenton Mill burned last night. I plan to continue the blog and will include pictures of its last night in future posts. We want to thank the firefighters who braved the cold and ice and fire and everyone who has contacted us today. Thank you. We loved the Mill and will miss it.

2015 02 06 blog 1971 04 00 02 S&S Festival2015 02 06 blog 1972 04 01 01 S&S New Day

CMU Fine Arts Studio

February 5, 2015


By 1973, the CMU Fine Arts recording studio was recording 100 recitals a year as well as producing records for CMU’s amateur theatrical group Scotch and Soda known for the debut of the musical Pippin. Some of our best memories were recording a CMU Kiltie Band concert at Carnegie Music hall in New York and being part of the sound crew for part of the 1969 Rolling Stones Tour. For Scotch and Soda we designed a home made six track recorder using three sets of quarter inch stereo heads (nine heads in all) and half inch tape on an Ampex data deck. In its original incarnation for the musical Something Personal we only had two channels of record electronics which we would manually replug to switch between heads. Also pictured is a Revox two track recorder and a Teac four track recorder. We used Advent dolby units and Stan Kriz designed a special system that could encode 90db of audio on standard Scotch quarter inch tape and also control the speed of the recorder using a huge tube amplifier for pitch adjustment.
2015 02 05 blog 1973 04 00 00 NRL Studio2015 02 05 blog 1971 04 00 01 NRL Studio

Transicap Microphones

February 4, 2015


The Transicap condenser microphone was designed in the early 1970s by John Hain and Stan Kriz, engineering students at Carnegie Mellon University and members of the campus radio station WRCT. The mechanics were hand lathed by my father in his shop in Baltimore, Maryland. The diaphragm was made of vacuum spattered mylar stretched over a brass backplate mounted in an epoxy resin body. The backplate was threaded into the epoxy body so that it could be adjusted to the correct capacitive gap. The bodies were made of silver anodized aluminum. We developed special tooling for stretching the mylar and adjusting the capacitive gap. Two special black anodized Transicaps were built and subsequently dissapeared from Exhibition Hall at CMU. The core of the electronics was a small metal bodied nuvistor tube which required an external high voltage power supply. For this reason, the microphones used a four pin cannon connector between the microphone and the power supply. A standard three pin cannon connector was used between the power supply and the mixing board. We recorded Stephen Schwartz’s (Wicked) New York audition tape at CMU using Transicap microphones and a hand made mixer. My favorite story from the session was Stephen putting thumb tacks in a CMU upright rehearsal piano to make it sound like a harpsichord.

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February 3, 2015


WRCT is the campus radio station at Carnegie Mellon University and in the late 1960’s Ken Lutz, a music major, decided to do a radio show based on recitals given in the Exhibition Hall of the College of Fine Arts. Since I was a technical drama major, I was familiar with the glass ceilings of CFA and I helped Ken by hanging the microphones to record the recitals. This entailed walking out over the two story glass ceiling on the mullions between the glass panes. In the process we discovered a way from the ceilings into an old fan room off the practice hall that had been locked for years. After some research and discussions with the Dean and the head of Physical Plant, both of whom thought the room belonged to the other, we were given a key and it became the music departments first recording studio. The picture with the record turntables is the WRCT studios in Skibo. The picture with the tape recorder was our first setup in CFA. In the 1960s, WRCT was mostly run by engineers and drama students. Between them they designed and built the equipment and created the content for the shows. Both the studio console and the small battery powered mixer shown were designed and hand built by the members of WRCT. Tomorrow, I will tell you about how we designed and built our own condenser microphones.

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Studio in a Grain Bin

February 1, 2015


My son, David, suggested that I write a blog about the Emlenton Mill and since this is February I thought I would start by writing about sound and recording, which I love. February, you see, is the month of FAWM (February Album Writing Month). For more information check out I figure that writing a blog every day is a little like writing a song every other day, except much easier. So, welcome to the Emlenton Mill blog. I’ll try to work in the Mill along with my love of recording.

The Emlenton Mill, built in 1875, houses a mill museum, an ice cream shop, a bunkhouse hostel, an Emporium that sells antiques, crafts and books and a number of secrets. One of these secrets is a recording studio in a gain bin.

Hidden away in a converted grain bin, on the third floor of the Mill, is a recording studio control room from the 1970s. It was originally located on the music practice floor of the College of Fine Arts at Carnegie Mellon University. It was built by myself and some friends from the campus radio station WRCT. But more about that another day. The Mill has a large number of grain bins which were used to store the different grains that were processed at the Mill. They vary in size from the size of a closet to the size of a railroad box car. The grain bin we chose for the studio is a small room located just off the main area of the third floor and required very little alteration. Most grain bins are built with sloped floors so the grain would gravity feed to the center of the bin where the output chute was located. This grain bin only required a new floor to support the studio.

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