Analysis of audio problems at the First Church of Christ, Scientist, Chattanooga, and reccommendations:

The current collection of electronics and installation is not well matched, and it's usage accentuates the problems. Specifically, due to speaker placement and microphone usage, the system is in a constant state of feedback suppression. A good example if how much better the system sounds when the wireless microphone is being used.

Some cost effective steps can be taken to optimize it's current configuration and usage, with an ultimate solution of a replacement of matched equipment, modern anti-feedback circuitry and better speaker placement.

In english: First we do what we can with what is there. Then decide on if it needs replacing.

Move the microphone holders forward in the lecturn to make it easier to place them “4 fingers” (2 to 3 inches) from the readers. Then lower microphone gain to reduce the need for feedback suppression, which is constantly working, which is why the readers voices are distorted. This is essentially just drilling some holes in the lecturn and moving the microphones.

Move the speakers in front of the lecturn/microphones. Again, to reduce feedback. This would require some longer speaker cables (about $75 for a pair) and a pair of speaker stands (also about 75.00).

Worth an experiment if the readers would use them.

A pair of cheap headset mics is $90.00 (for a pair, $45 each effectively)

System upgrade/replacement:

Replacing most of the system, to matched integrated main audio system, and using the existing Bogen GS150 to power the 70v speakers is the best suggestion of myself, and some experienced friends. For it's excellent sound reproduction quality and integrated feedback suppression, the Yamaha EMX series seems to be the best fit. There are “packages” that include everything, with the sweet spot being the EMX2 package with 12“ main speakers.

Example system and price: $1,199.99 Pieced out the mixer/amp is: $399 and the speakers $649, and you would still need stands and cables. Might as well buy the package for just a little more. The spare mics and mic stands would be useful for presentations/speakers.

  • Budget for some (1/4 Phono to RCA) adapters and misc wiring: $100.00
  • Optional: Stretchy white spandex speaker covers: $49.99 each. Stand covers: $32 each.
  • Optional: Wireless headset microphones: $90 to $300 each.
  • Total budget: 1400.00 to $2200.

Recommended: System, shipping plus adapters and misc: $1400.00

This systems's “monitor out” jacks would provide signal to both the Bogen GS150 for 70v audio, and the FM transmitter/receivers for auditory assistance.

Installing this would be a project that if allowed to do it correctly, I'd build a slideout or rollout into the lecturn that would allow everything to be properly mounted, yet would slide out for easy access to the wiring and power strip.

Answers to common questions:

Can it be done cheaper: Yes, you can buy mismatched gear or off-brand and it would work.

Would I do it using cheaper gear: No. I have some experience with Fender and Yamaha professional equipment and feel it is worth the price.

What am I willing to do: Mike and Nancy would donate $500 to this project, and I am willing and able to create a cabinet and install it all properly.

If the board/church chooses to do this: I'd buy it all online, test it in place (at the Church) quickly, and return it if it does not meet expectations. If it sounds awesome, I would do a more permanent installation.

Where would I place the speakers: In front of the lecturn, as far to the sides of the church as practical.

Existing equipment overview:

Shure MX418 microphones: Current technology, good conference/lecturn microphones with a distance factor of 1.7 (up to approx 1.7 feet) and a wide pickup area. They also pick up a lot of side noise, which causes feedback, which can be compensated for by better placement to the readers. Optimum placement would be “4 fingers” or about 2 to 3 inches. These should be great microphones for the intended use, the only better options would be headset microphones or “shotgun” (very directional) microphones.

Bogen GS150 amplifier: An arcane piece of equipment that is underpowered for the current speakers, but does provide 70v audio out for the childrens room / downstairs (needed because of the distance to the speakers). It does not have integral feedback suppression. As a “standard” piece of gear for audio installers these are still for about $450.00, mostly because they support both 70v and 8ohm speaker output (approx 150 watts max).

Shure DFR 11EQ: Original generation feedback reducer. Worth the $25 they sell for on eBay, maybe. This is part of the problem, it was kludged into the system.

Galaxy Audio LA4 Speakers. These were selected because they are available in white, and are 16 ohm speakers. Which means 2 of them in parallel are technically are an 8 ohm speaker and match the Bogen GS150 rated output for 8 ohms. Except they are very underdriven by the Bogen, which should be capable pushing 300 or more watts to drive 8 speakers (each cabinet has four 4” speakers, which is why they are “line array” speakers). I enjoyed reading reviews of these, including one that compares them to “fishsticks”.

Shure digital wireless mic and receiver: Good stuff. Older but solid.

PPA T4 Auditory Assistance Transmitter: Odd gear, keep as long as it works.