PA Project for Church

[reubensm]

Let me try and list the equipment which they are using:

1) SA-100M Amplifier for monitoring

2) SSA-250M Amplifier which drives 4 speakers

The second amp drives 4 wall mounted SRX-120DX speakers

In the recent past, I helped finance a Sound Processor - Soundcraft EPM

The 8 Mics in use are:

1) Ahuja G662S - podium-1
2) MX (no other numbering or lettering) - main alter table
3) Audio Technica ATR1300 - podium 2
4) Ahuja SHM 1000XLR - choir
5) Ahuja AUD-101XLR - choir
6) Shure SV100 - choir
7) Ahuja SHM 1000XLR - choir
8) Wireless Ahuja AWM 690V - occasional use

 

[vardesh]

hi,
Bookmarked link related to church sound system.

A Guide to Church Sound Systems | Benton Electronics

surely you have more info but felt like sharing.

Rgds,

 

[reubensm]

Here are some pictures and of the church hall and the dimensions:

This is a view of the hall from the door at the back of the hall. The 4 speakers on the walls are clearly visible:

This is a view of the hall from the right corner of the alter (was standing on the alter). To the far end of the hall, on the right, is the entrance of the hall, in itself a little sitting area:

Here's a better view of that entrance area:

Another view of the alter from the rear (right side) of the church:

Another shot at ground level showing the entrance of the church to the far right:

What they call the control center, the processor is kept covered:

Hall dimensions are as follows:

Entire Hall: Length-80 feet, Width-30 feet, Height-16 feet
Alter Area: Length-12 feet, Width-30 feet, Height from church floor - 2.5 feet, Height from Alter to roof - 13.5 feet
Entrance Area: Length-30 feet, Width-12 feet, Height-16 feet

Ceiling Type - Flat Concrete Slab
Floor Type - Marble
Alter Floor - Red Carpet

 

[reubensm]

Ceiling Type - Flat Concrete Slab

forgot to add, the roof is supported by concrete beams, hence is not a perfectly flat surface.

 

[diesel engine]

Both Ahuja power amps shown are trafo coupled in output. not much good for music. freq resp max is below 10 KHz. Ahuja have direct coupled ones.

 

[reubensm]

Well the amps are used predominantly for speech only so think they would suffice. Last weekend, I re-soldered all the microphone cables. This weekend, will try to spend some time with the amps.

 

[Thad E Ginathom]

It's a typical rectangular hall, such as might be used for many kinds of functions and/or performances. My experience of trying to escape the harshness of reflections in music performances suggests that some absorption on the side walls, maybe roof too, would make listening much more comfortable for the people.

 

[keith_correa]

IMO, the equipment is reasonably good and what the church needs is bipolar speakers on the walls.

 

[reubensm]

my second son was having fever through the night, hence I cancelled my plans for the day, went to church in the morning and collected the bigger amp and brought it home for servicing and modification. The pots needed a change, the reset switch has ceased, bias needed a check and the Parish priest had requested a mod as the amplifier generally had a very boomy signature (even with the tone controls in flat position). Got all this straightened out, while I kept the little sick man engaged. Here are the pics:

(sorry I don't have a work bench yet so had to use my mother-in-law's sewing machine table side as a temporary work bench)

Opened up the amp:

Surprised by the very neat layout:

Master technician evaluates (under the influence of fever medication):

The Output Stage and Tranny:

The Power Supply and Tranny:

2N3055 Transistors on the right side headsink:

2N3055 Transistors on the left side headsink:

Eureka!! I've found the problem!!

Time for a repair job:

Man at work!!

Old Pioneer car speakers used for testing:

The front panel after completion of work on the pots:

A small mod, added a fixed presence control for improved speech performance:

Front panel screwed back after the reset button was rectified:

The rest of the amp's panels screwed back:

Fully serviced and ready to go:

View of the back panel:

Testing with my cd player:

After an hour's testing. Used APJ Abdul Kalaam's "Wings of Fire" for the test. The amp will be delivered to the church and installed for tomorrow morning's mass:

 

[reubensm]

Was amazed about the build quality of this Ahuja amplifier. Its built like a Tank. It sounds pretty good for both speech and music as well.

 

[reubensm]

The amp was installed in the church today and it sounded brilliant. Some easy servicing and a simple mod made a world of difference.

 

[reubensm]

Am down with a sore throat and fever today (with the kids) but did not want to lie and bed and kill time. So drove by the church and picked up the second amp (the 100watt one). This is an older amp and when I opened up, it looked like it had been through a world war. The feedback from the parish priest was that this amp sounded very dull and muffled. Also after the 250 watt amp was installed this morning, the difference between the two was like between a colour movie and a black and white movie. This called for some hot-rodding

Took the amp home and opened it up on the makeshift work table:

The inside, all dusty:

The power tranny and elementary bridge rectifier and filter caps:

The power output tranny and the 2N3055 output transistors:

View of the PCBs:

The rear of the amplifier:

The input stages:

The poweramp, tone controls and level indicator board:

A simple mod for speech enhancement, a permanent presence control:

Another hot-rod mod, increased the trebles a bit (it sounded very dull otherwise):

Testing thereafter with Joshua at the controls, sounded quite good and aggressive for speech and music.

Currently a work in progress, need to tackle the pots, some caps and clean up the whole thing. Will do this tomorrow. Need to get some rest.

 

[Nikhil]

Great stuff Reuben!

Can you share what you did in terms of the presence control?
Just read that this is a sort of upper mid range boost - what did you use to do this?

Is the weather the culprit for the wear and tear? Kerala does have high humidity.

Regards.

 

[reubensm]

Great stuff Reuben!

Can you share what you did in terms of the presence control?
Just read that this is a sort of upper mid range boost - what did you use to do this?

Is the weather the culprit for the wear and tear? Kerala does have high humidity.

Regards.

A typical circuit:

My version:

I should actually call it a loudness control rather than presence.

 

[keith_correa]

But why would you need that "presence"/"loudness" mod - the amp has bass/treble controls which could be used to boost the treble, at low volumes right?

 

[reubensm]

Yes but the amp has 2 sets of level controls, one for each input and a master volume control. The loudness control enhances the vocals (the feed comes from the processor).

 

[Thad E Ginathom]

I think I can see why they call it "presence."

Loudness controls boost the treble and the bass, the areas in which our ears become less sensitive as the volume drops. but presence is in the mid range where vocal frequencies are to be found, so it is sort-of opposite to loudness

 

[reubensm]

The amp is all serviced and returned to the Church.

Yesterday, I took my NAK DR3 to Church with a Brand New Maxell C90 (opened the shrink wrap, just before recording) and recorded the Holy Mass in English, with the line out directly from the mixer. I could not get to Mr. Kuruvila's to get back my reel deck so had to use the cassette deck instead. Was surprised to note the quality of the recording. Sounded like it was progessionally done. Will be using these recordings for determining speaker placement, sometime this week.

 

[Simon Wires]

Reuben,

Your project got the luck of the Irish, I guess!! But it also comes along with a sad story.

That uncle who shared you that Grundig spool tape passed away on 30th May at the age of 76. On that day,I was out of city, and somehow managed to reach the crematorium to pay my last respects. That moments reminded me of Johnny Cashs Doc-Brown song, but only with a slight exception that there were not many present there, as the custom calls it.

As said earlier, he was a sound & acoustics engineer who worked with quite a lot of companies and his last assignement was with T-series. As happens with the story of many audio enthusiasts, in this era of ipods & iphones, the children are not interested in these tangible & outdated audio assets and so the call landed on me. They were LPs , casettes, a TEAC Z-5000 master tape deck (lovely one, but needs little service), this robust DIY speakers (pic below),a huge load of labelled tiny boxes filled with ICs, Resistance, LEDs, Caps etc etc, 100+ nos of recording tape heads (Japs) etc. Only thing they wished to keep themselves were the spool tapes, for it had some memorabilia recordings.

Little about the speakers.. Its robust and solid built like an Enfield bike,not so good in finish like WILLYS Jeep, each one weighs around 50Kg, and to my novice ears it always sounded pleasant when he played Frank Sinatra & Shadows. Whenever I suggested him to buy an Epos/Wharf, in a flash he would throw back a frown laced with his audiophile signature.Such was the love he had over this speakers, who was also an ardent Tannoy fan. I remember him telling me that he designed it by keeping one woofer set idle with wool packing, inorder to balance the pressure or tone, which , with my limited knowledge I failed to grasp, and he is no more now to explain that. All i could make out is, the horn tweeters were Motorla Mexico make, and I didnt ponder further about other specs.

If this speakers would find place in your charity project, please say little prayer for the departed soul of Mr.Ragunathan Iyengar, and take it.


Regarding shipping part, dont worry, I would pick it up from his house this weekend and dispatch it in few days time.

 

[reubensm]

Oh, its really sad to hear about his passing. Infact, recently I listened to the tape and its recording was pretty good. Sorry to hear about what happens with such situations. Similar scenario with my father as well. He had a load of audio stuff, things like a mint Garrard SP25 turntable, NAD 1020A preamp which was almost brand new, philips hi-q speakers and loads of cassette recorders, speakers, components, video equipment and what not. When he passed away, I sold/auctioned off all the stuff and we donated the earnings to charity. The only thing we retained was his LP record collection. The SP25 turntable with its original Shure M75-6s cart, Hi-Q speakers and the NAD 1020A preamp are with our forum members.

I will convey the background of this donation to the Parish Priest and have him pray for the departed soul during the holy mass.

On another note, from your note I gather that one speaker in the box is actively connected while the other is used as a passive radiator. These look robust and would do well in the Church.