Ray Rayburn's Technical Page

I have expanded my offerings to include precision test microphones (including a couple of models I hand make in my lab) and precision wireless measurement links.

Why Do Frequency Response Curves Matter?

I am now selling the Superlux™ line of microphones. They include fine 1" diaphragm condenser mics that sound similar to the Neumann U87's, and an excellent line of reinforcement mics.

Audix offers some unique microphones including their "microboom" choir mics. Check out their complete line here.

Lectrosonics makes some of the best wireless microphones in the world. They are the dominant brand in the film sound, television production, and ENG worlds. Their latest offerings are priced similarly or less than the better wireless offerings from other brands, but deliver superior sound quality, ruggedness, and reliability.

Mipro™ wireless microphones range from basic fixed frequency VHF and UHF models to full featured modular computer controlled 100 channel frequency agile UHF models. Mipro has made wireless mics for many companies including Beyer. Now you can get these quality wireless systems at better prices.

I also sell Avlex™ power outlets and sequencers. These are well made units at very reasonable prices.

Quality used sound level meters with fresh calibrations.

Terrasonde Audio Toolboxes and other new and refurbished audio and acoustic test equipment.

If you have looked with longing at the Ocean Way HR-2 monitor speakers "designed by Alan Sides", have I got a deal for you. Those speakers are actually RCA LC-9a with added subs. I own a pair of RCA LC-9a customized with upgraded drivers, and they do sound very sweet. GC Pro sells these for $38,600.00, but I will sell you my pair for a mere $20,000.00. Email me at Ray (at) SoundFirst (dot) com for more details.

Check out the Thursday 18 November 1999 Wall Street Journal. It has a cover story on Vintage Microphones. The reporter did his homework, and interviewed Klaus Heyne, Stephen Paul, and Allen Sides among others.

Here are a set of response curves of a Klaus Heyne modified Neumann U87.

Here are sets of response curves of my ADK A-51s(LE) mics, sample #1 and sample #2. At 1/10 the price or less of the Neumann U87, these chinese made mics look and sound quite similar to the Neumann U87's!

Information on GenRad measuring mics is hard to find, particularly for the 1" ceramic mics. I have posted here scans from a GenRad manual. This also includes lots of valuable information on the directional characteristics of "omnidirectional" microphones, difraction effects and other related microphone characteristics.

The best contact, switch, and potentiometer cleaner I have ever used is Cramolin Contaclean, formerly known as Cramolin Red. Caig used to import this from Germany in bulk, package it in spray cans here in the USA, and sell it as their own product. It seems at some point Caig decided to sell a different product (maybe they make more money on it?) Caig then put out a totally misleading story about the EPA and Cramolin to explain why it was no longer available. Actually the EPA had problems only with the propellant Caig added when they packaged Cramolin in spray cans, and not with Cramolin itself. Caig's replacement product is called De-Oxit, which in my experience does not work anywhere near as good as Cramolin Contaclean. A couple of years ago I discovered Cramolin in Germany, and bought a case of Contaclean. It works just as good as it did back when I was buying it from Caig. The German packaging puts over twice as much in a can as Caig did, which makes it a better value. Unfortunately I don't know of a current USA source.

Here are my spreadsheets for calculating speaker wire size with new comments and instructions as of 2/27/2000. They are compressed using WinZip. They are in Excel97 format. The first is for low impedance loudspeakers. The second is for constant voltage systems.

Syn-Aud-Con is the premier training organization teaching sound reinforcement system design.

Church Sound Check is one of the best web sites and email discussion groups on church sound and other church technology issues.

Church Production Magazine is a resource and an educational tool for churches. I have written several articles for them.

Columbia College Chicago has an outstanding Audio Arts and Acoustics program founded by Doug Jones. This is the only 4 year college with courses on the TEF analyser. They have intensive courses in Acoustics and Audio Contracting.

Ken's Links on the ProSoundweb web site is the best starting place for finding professional audio companies. ProSoundweb also has many other useful resources including live chats on various audio topics.

Jim Brown is a top audio systems consultant. His web site has some useful articles. Here is his article on Wireless Mics. Another excellent article is Why Churches Buy Sound Systems Three Times, and How You Can Buy Only One. Check out all his articles here.

Rick Chinn is a design engineer and consultant in audio systems. There is a lot of great stuff on his Uneeda Audio page.

Craig Janssen is a top consultant who has probably designed as many contemporary church sound systems as anyone in the business.

Jensen Transformers makes some of the worlds finest audio and video transformers. It is also the place to go for some excellent and accurate Application Notes.

Benchmark Media Systems makes some of the world's finest mic preamps, distribution amplifiers, Analog to Digital and Digital to Analog Converters. Al Burdick, the company President, has written a must read document "A Clean Audio Installation Guide" (requires Acrobat reader).

Below are some of my technical comments from the Church-Sound-Check and Syn-Aud-Con email discussion groups. I will add to this as I have time.

Cleaning and Demagnetizing of tape recorders and duplicators.
Serial Interfacing
Equalizer Phase and Time Response
Filter Slopes
A brief history of the XLR connector.
3 Phase Power.
Flashlight Comparison.

Below is an article I wrote for Technologies for Worship Magazine:

Analog Interconnections. The introduction was written by Vance Breshears.

I edit the Audio E-Newsletter for Technologies for Worship Magazine. The Archive of the E-Newsletters can be found here. You can also subscribe to the E-Newsletter at that same location.

"Master Reference Book for Disc Recording" issued in February 1940 by the Recording Department, RCA Manufacturing Company, Inc. Camden, New Jersey, USA. Don't try to download this unless you have a high speed Internet connection as this is a 386 page book and the file size is 46.7 MB. Thanks to Doug Jones for the conversion of this historic book into pdf form.

Scully Lathe
RCA MI-3027 Microphone

This is the internal use only book that covers all the equipment used to produce sound recordings at RCA Studios worldwide as of February 1940. Only 15 copies of this book were ever made. This copy was issued to the studio in Hollywood, CA, and may be the only copy left in existance. It came into my possession when I worked for RCA Records in NYC and they threw it out in the trash.

It contains manuals, schematics, photos and more for:

Microphones
Filters and Compensator Units
Microphone and Re-recording Mixers
Amplifiers
Monitor Equipment - Meters, Loudspeakers Etc.
Recorders, Pickups and Related Accessories
Power Supplies
Recording Machines
Turntables
Test Equipment
Transmission and Schematic Diagrams
Equipment Assembly and Inter-unit Wiring Diagrams
Testing and Maintenance of Equipment
Operation Standards
Frequency Response and Performance
Material and Dimensional Data on Recording Blanks and Records

Back to Home Page.

Edited 2/14/2010

Mailing address:
Ray A. Rayburn
1630A 30th Street #163
Boulder, CO 80301-1014