Ray Rayburn's Technical Page

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, with one model that is more neutral sounding, similar to the Shure KSM-32 in sound. They are even less expensive than the ADK mics, but are of excellent quality.

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™ mixers. These are well made mixers at very reasonable prices.

Quality used sound level meters with fresh calibrations.

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

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.

In January 2000 the FCC ruled in favor of allowing legal low power broadcasters on the FM band. This provided a great opportunity for churches and other groups to have their own radio station. Here is the FCC's Statement (MS Word file) and the official Report and Order (requires Acrobat reader) as published in the Federal Register. This is the FCC's web page devoted to Low Power FM. At this time the FCC has suspended their Low Power FM Channel Finder since they don't know when the next application window will open. When it does reopen, contact Bill Sitzman of Independent Broadcast Consultants at (607) 273-2970. He can determine exactly what frequencies are available in your area, and produce your complete license application.

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 directed 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.

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Edited 1/24/2007

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