A bit of advice for a chapel's sound system ?

00940

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2003-09-03 12:17 pm
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So I've been asked to have a look at a chapel's sound system and I've got a few questions... anyone willing to share some experience ?

I attach below a rough sketch of the place. Altar and pulpit are normally in position A but are sometimes moved to B (weddings mostly). Currently, the sound system is as such: a 100W TOA amp (100V line, 4 mic inputs) and 5 small speakers (4" fullrange, closed, with a 100V xformer rated at 25W). Those 5 small speakers are attached to the wooden beams, directed directly towards the ground, 2 on beams 2 and 4, 1 on the central beam.

The speakers are falling apart (awful quality stuff dating from the 70's at best) and the amp is getting noisy, on top of having only DIN connectors. So everything has to be changed, including wiring (which was awfully botched, a miracle it held for so long). And of course... everything has to be done on the tightest budget (otherwise they would have gone to a pro). The good news is that the current system, even as bad as it is, is considered sufficient for the needs of the place.

So here are my questions:

- Do I stay with a 100V line system or do I move to 8R speakers ? A 100V PA is pretty much idiot proof but the choice in affordable speakers (and amplifiers) isn't as good.

- If I stay with 100V speakers, the visaton wb16 seem ok as a modern replacement. Let's say I buy 4 of those... do I set them up like the previous speakers (for example, 2 on beam 2 and 2 on beam 4, firing downwards) or is there a much better way to proceed ?

Thanks for any tips.
 

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00940

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2003-09-03 12:17 pm
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Yes, I'm considering it too. That's plan B actually. I'm slightly worried about feedback though and uneven coverage in configuration B.

So, it's pretty much either 6* visaton WB16 + Apart MA 125 Amplifier, for a total of 963€ or 2* LD System sat442 + yamaha emx212s, for a total of 913€.

The first config is a 100V system, the second one isn't.
 
Having done a few hundred of these small church systems, I would overhaul the TOA (If it is a made in Japan model) and replace the existing loudspeakers using 100V wiring.

The TOA probably used those audio designed transistors that are mostly out of production and highly sought after. Change the power supply capacitors, clean the controls and clean the low level mute relay not the output one.

A column will effectively throw three times it's mounting height. So distributed will probably work better.

Be sure the overhead mounted loudspeakers have safety cables in addition to a secure mounting.

Be sure the new loudspeakers are intended for the use and not stereo systems as there is a difference in efficiency. The ones you mention are fine.

Cost of the parts should be less than $750.00 or if using cheap loudspeakers as low as $150.00.
 

00940

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2003-09-03 12:17 pm
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Thanks for the advice.

What do you mean exactly by "throw three times its mounting height" ? Sorry, I'm not a native English speaker and I'm sometimes lost in translation :/

The TOA is a a-512e. Assembled in Taiwan. Apparently around 1987 according to this website: Mixer Power Amplifier A-512E Ampl/Mixer TOA Electric Co., . I attach the schematics coming from that website.
 

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If the loudspeaker is mounted 5M off the floor then it will project effectively to a distance of 15M. Much past that people will complain it is not loud enough. If you turn up the volume people close to the loudspeaker will complain it is too loud.

The TOA A-512 is not one of their better amplifiers. You might look on the net for a used A-912A for a very inexpensive well built used amplifier.
 

00940

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2003-09-03 12:17 pm
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What I was thinking for the columns was to mount them not on the beams but vertically on the wall, on either side of the altar. I hadn't consider putting the columns on the beams.

As their vertical dispersion is only 30°, I'd need to put them both on the central beam to cover the whole width of the chapel. Horizontal dispersion being 120°, it'd give me a fairly uniform coverage (at 1.5m above the floor) only up to about 6m on either side of the beam... I'd only cover half the place. So yes, distributed looks indeed better from the top.

Thanks for the tip on the a912. Sadly the only offers seem to be in the US. It might not have been distributed in Europe.
 

00940

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2003-09-03 12:17 pm
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I was thinking some more about it. What about this ? Proportions of the drawing are off since it is a quick draw but it seems workable.

With two columns (120x30° dispersion) attached on either side of the center beam, I achieve a fairly good coverage of the whole place, except around the altar and pulpit. It creates a hole in configuration B but it is a bonus in configuration A.

The other drawing is what I had in mind initially for columns, attached under beams 2 and 4.
 

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I'm late to the party, but our church has a very similar layout (and size). We ended up (on my nickel originally) purchasing 4 ea of the used ALESYS RA–100 amplifiers, and running (hidden) bright orange 10 gauge Home Depot 100 foot extension cord cable to a set of Bag End and Jensen 8 Ω speakers, positioned around the place. 4 RA–100s gave a total of 8 adjustable channels, which allowed all 8 speakers to be individually balanced (over time) as we learned where the hot and dead spots were.

With nail-polish, the “best sound” spots were marked on the face of the RA–100s. That way they could be readjusted for other venues and such (with different color nail polish!) and then easily reset in a fool-proof sort of way.

For our input we bought a used Yamaha 01-V (full digital, 16 live channels) for mike mixing, and for all sorts of creative instrument pickup. The whole thing was mounted in a parishioner's custom-built rack with castors, so we could wheel it about. This system was the "music system", independent of the altar sound system (that has both wired and wireless mikes and a couple of boundary-layer Shure mikes too.)

It is kind of nice to have the choral system separate from the ministry system. Allows separate master volume control without causing the ministry system to start hoot'n and holler'n with feedback. Works well.

Each of the Alesys amplifiers cost less than $100 each. EBay. Bought 5 to get 4 working ones, and spent a total of $350 all-in (for amps). The mixer was $500 in mint-used condition. The rolling rack was free, due to the parishioner having a cabinet making hobby. We spent a tiny bundle getting darn good microphones (a lot of them) and equally good mike stands. I personally made several in-cable FET "direct box" type amplifiers for all the passive-pickup devices. (Harp, several acoustic guitars, electric but unamplified bass, a cello, several piezo pickup violins, and so on.)

Anyway, put that system in 10 years ago, and it is not only still working, but nothing has broken except a few mike cables, and the speaker-wire connectors (which just needed resoldering)

Good luck!
GoatGuy

PS: remember it is a ministry, and they're TOTALLY not in need of sparkly new equipment. Excellent "top of the line" used equipment is a very prudent thing to consider. And just as fun to buy. For us DIY'ers
 

00940

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2003-09-03 12:17 pm
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Thanks for the inputs.

@simon7000: ok, distributed it is then.

@GoatGuy: our needs are more modest than yours were, it's just voice and background music, no live instruments (well, there's an organ but it certainly doesn't need reinforcement). So no need for a separate music/ministry setup. They bought a bunch of sm57/sm58 a while back so I'm covered microphones wise.

Agreed on buying used. But the second hand market for PA systems really isn't great around here. :/ A lot of junk and the good stuff is overpriced.

And the last complicated thing is that it is a XVIIth century chapel so the system has to be "not too visible". The long walls are covered with paintings wherever there isn't a window. So there's a lot of incentive to put the sound system up there on the beams.
 
Whatever amp you've got, if it is adequate but getting noisy, I'd put 20E of new electrolytic capacitors and volume control in it. Transistors don't go bad, e-capacitors and potentiometers do in 15-20 years. People send a lot of equipment to the dump because the rubber parts are bad. Like scrapping a car when the tires are bad. Buy the long life electrolyic capacitors, >3000 hours service life. That life is shown in the selector table at digikey and can be shown at farnell. Electrolytic capacitors are the ones with plus near one lead or minus pointed at the other. They are like beer cans sealed with rubber, cheap rubber in most cases, not silicon rubber which it could have been. Some rare electrolytics have a voltage NP (for non-polar) instead of a plus or minus, and short life tantalum caps look like peanut M&M's with a plus near one lead. All these will be over 1 uf (or mf they were marked before ~1980). I've had tantalum caps on the input make frying pan noise before.
Connectors can be cleaned with a bent tip pick and maybe a little spray contact cleaner. You have to be near salt water usually for there to be a serious corrosion problem on connectors. Connectors do have to be removed & replaced to remove oxide sometimes.
A WP35 iron, some rosin core tin lead solder, a dvm, pliers, cutters, strippers, 6 way screwdriver, bent tip pick, safety glasses, two or three afternoons, there you are, nice sounding amp for another 15-20 years.
Lots of pro sound people are negative on old amps, but I'm sitting here listening to Lp's on a 1970 build amp- with new e-caps and fan. The creaky old first generation silicon transistors still work fine in this amp. Speakers do wear out sometimes, they are inherently built of rubber except the foam surround ones are worse than rubber for short life.
 
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