I've been asked to spec out and install a PA system in 4 halls in a Church. There huge, not Westminster Cathedral but its the biggest church I've ever been in.
The main hall is 160 ft by 150 ft, the ceiling height is 180ft. Its a morbid damp stone building with fine acoustics for a bunch of choir boys I'm sure. Yet I've never done a church with echo for days.
They have no budget to speak of and want massive monoliths with drive units stacked to heaven. My plan is to install four (12 inch 4 ohm) drive units per side to just flood the place with sound from 40Hz/2.5Khz, maybe some horn drivers and strap a Cloud type PA amplifier to them. All made from 18mm ply. There will be no cross overs on the 12 inch drive units. I'll wire them into dual series and then parallel loads per side to maintain 4 ohms for the amplifiers. This must be as cheap as possible, I know they probably won't pay for all the hardware never mind my time and labor. This is a real charity case and a personal challenge for me.
Any suggestion on the best bang for the buck are welcome as I've never done PA systems on a shoe string budget.
The main hall is 160 ft by 150 ft, the ceiling height is 180ft. Its a morbid damp stone building with fine acoustics for a bunch of choir boys I'm sure. Yet I've never done a church with echo for days.
They have no budget to speak of and want massive monoliths with drive units stacked to heaven. My plan is to install four (12 inch 4 ohm) drive units per side to just flood the place with sound from 40Hz/2.5Khz, maybe some horn drivers and strap a Cloud type PA amplifier to them. All made from 18mm ply. There will be no cross overs on the 12 inch drive units. I'll wire them into dual series and then parallel loads per side to maintain 4 ohms for the amplifiers. This must be as cheap as possible, I know they probably won't pay for all the hardware never mind my time and labor. This is a real charity case and a personal challenge for me.
Any suggestion on the best bang for the buck are welcome as I've never done PA systems on a shoe string budget.
no budget ha?
in that case I highly recommend you go ahead and buy remaining AURA 3" fullrange drivers
they deliver wonderfull midrange, I know, I used them in many projects
and you get them for $1 each!
they are 16 ohm, so just slap 4 in paralell and you get 4 ohm, that you make as many 4 ohm sets you need to get coverage
you will not regret it!
The Madisound Speaker Store
in that case I highly recommend you go ahead and buy remaining AURA 3" fullrange drivers
they deliver wonderfull midrange, I know, I used them in many projects
and you get them for $1 each!
they are 16 ohm, so just slap 4 in paralell and you get 4 ohm, that you make as many 4 ohm sets you need to get coverage
you will not regret it!
The Madisound Speaker Store
Yep, echo for days?? ha ha...
You will need *extreme* control over dispersion at minimum.
If you can you need to convince the powers that be to hang what would be called "tapestries" from the side and rear walls...
In reality to do this job, I'd consider a down firing system... perhaps time delayed as it goes back down the hall...
Also you have to watch how much power you dump into this echo box... once you reach a saturation point all you will hear is hash and noise...
Bass is easy if there is space for a horn under a riser or similar...
Got pix??
What is the program material?? just voice, or is there some rock band??
Cheap... ha ha ha... what sort of cars do the people who run this place drive, just asking...
_-_-bear
You will need *extreme* control over dispersion at minimum.
If you can you need to convince the powers that be to hang what would be called "tapestries" from the side and rear walls...
In reality to do this job, I'd consider a down firing system... perhaps time delayed as it goes back down the hall...
Also you have to watch how much power you dump into this echo box... once you reach a saturation point all you will hear is hash and noise...
Bass is easy if there is space for a horn under a riser or similar...
Got pix??
What is the program material?? just voice, or is there some rock band??
Cheap... ha ha ha... what sort of cars do the people who run this place drive, just asking...
_-_-bear
Require the women to wear hats, and the men to wear suits. Pad the seating. Carpet the aisles.
Then add some pitch shifting to that natural reverb for that darth-vader fear-of-God sermon... Nobody will understand a word, but they'll all suddenly become believers. "Death Comes Unexpectedly..." Excuse me if I push the list rules, staying on the acoustic attributes and not getting into the realm of the supernatural.
Then add some pitch shifting to that natural reverb for that darth-vader fear-of-God sermon... Nobody will understand a word, but they'll all suddenly become believers. "Death Comes Unexpectedly..." Excuse me if I push the list rules, staying on the acoustic attributes and not getting into the realm of the supernatural.
i'd like to know if they have an existing pa and what it consists of i.e. mixer/amp,music sources,speakers 70 v distributed or...
in reading your initial post it sounds like your determined to make this rig stereo but given your architectural acoustic situation stereo imaging and original sources like an open mic may not mesh well unless properly implemented.
central clusters (speakers) hung over the source area generally yield the best overall coverage while minimizing comb and reflec room effects.if i am picturing the room as stated it's as wide as it's deep with a high centrally vaulted ceiling correct?
then two vertical (column) arrays of four 12's in a coincident pair would be the cat's meow.
in reading your initial post it sounds like your determined to make this rig stereo but given your architectural acoustic situation stereo imaging and original sources like an open mic may not mesh well unless properly implemented.
central clusters (speakers) hung over the source area generally yield the best overall coverage while minimizing comb and reflec room effects.if i am picturing the room as stated it's as wide as it's deep with a high centrally vaulted ceiling correct?
then two vertical (column) arrays of four 12's in a coincident pair would be the cat's meow.
Adason's suggestion for the Aura's is a good one. Used in long line array's would help beaming in the vertical plane so you can throw less energy on the floor and into the ceiling, reducing echo. Best way to achieve some modicum of intellibility at reasonable cost. Forget modern music. The acoustics of a large church belongs to a certain kind of music, in effect, choir/organ mucic and the acoustics of churches grew up together. Modern music is just too fast and the whole place will just muddy up with reflections, whatever PA you put in.
actually that will be certain death, vacuphile, since it will throw way too much energy into the side walls, which are hard stone... (I assume). Ceiling echo is likely fairly easy to discern as a separate sound compared to side echo which will arrive much closer in time to the original signal, more so the farther back you get...
You might want to study those phased arrays that they are using in stores now to put sound directly in front of the screens, etc... that might be a solution in such a situation...
_-_-bear
You might want to study those phased arrays that they are using in stores now to put sound directly in front of the screens, etc... that might be a solution in such a situation...
_-_-bear
Hi,
Vertical line arrays with those cheap drivers is the way to go.
Your really looking at only good speech intelligibility for a miked up speaker,
and possibly a half reasonable attempt at background music etc.
this may help : http://www.pispeakers.com/ssdm_99.pdf
Your looking at a very old school PA system, and you have to work out
whether you need a 100V line system, with tapped autotransformers
for individual speaker level setting. You can make each speaker
crudely relatively adjustable in level by changing the wiring for each.
Look at making each high impedance and all in parallel off
one big amplifier if your not going for a 100V level system.
rgds, sreten.
Vertical line arrays with those cheap drivers is the way to go.
Your really looking at only good speech intelligibility for a miked up speaker,
and possibly a half reasonable attempt at background music etc.
this may help : http://www.pispeakers.com/ssdm_99.pdf
Your looking at a very old school PA system, and you have to work out
whether you need a 100V line system, with tapped autotransformers
for individual speaker level setting. You can make each speaker
crudely relatively adjustable in level by changing the wiring for each.
Look at making each high impedance and all in parallel off
one big amplifier if your not going for a 100V level system.
rgds, sreten.
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Bear, it has worked that way for ages in churches and there is a reason for it: nothing else really works to keep speach intelligible.Of course mounted as far away from side walls as possible, and with each array covering only segments of the audience.
That sounds like crap, I know, but it is the only way to go on a no-budget basis.
Phased arrays would cost a lot on electronics.
I have a 100 Aura 3" (the better ones Keele used for his bananaspeakers, not the 1 $ items) in my workspace for an experiment with a ring array, which might be the solution for a problem like this, but time is the issue. I haven't conducted the experiment yet, so I can't give an advise in that direction at he moment, but it might work. The background is that theoretically, a ring radiator has twice the directivity of a contiguous radiating surface with the same diameter.
That sounds like crap, I know, but it is the only way to go on a no-budget basis.
Phased arrays would cost a lot on electronics.
I have a 100 Aura 3" (the better ones Keele used for his bananaspeakers, not the 1 $ items) in my workspace for an experiment with a ring array, which might be the solution for a problem like this, but time is the issue. I haven't conducted the experiment yet, so I can't give an advise in that direction at he moment, but it might work. The background is that theoretically, a ring radiator has twice the directivity of a contiguous radiating surface with the same diameter.
Hi,
You can learn by observing, e.g. look at PA systems in railway stations.
You should find lots of line arrays, wide horizontal dispersion but narrow
vertical dispersion, giving the throw, aimed at typical head height.
And FWIW the length of each line array determines the lowest frequency
that has good throw, the effective bass depth of a line array is its length.
There is obviously no point extending this length to beyond driver roll-off.
rgds, sreten.
You can learn by observing, e.g. look at PA systems in railway stations.
You should find lots of line arrays, wide horizontal dispersion but narrow
vertical dispersion, giving the throw, aimed at typical head height.
And FWIW the length of each line array determines the lowest frequency
that has good throw, the effective bass depth of a line array is its length.
There is obviously no point extending this length to beyond driver roll-off.
rgds, sreten.
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So what , our government havent had a budget in 4 yrs and look how they spend ...
Thats the way I'd do it too, a single driver facing up towards the ceiling with a 45 degree firing angle, just like in the war movies of yester year.
If this is a charity case then your gonna want it to be as cheap as possible
Make the single driver as loud as the dickens and pound that sucker with whatever it can handle into a horn if you can budget for it. This has the added benefit of the older folk who sit up the front not needing their hearing aids.
If there is no budget then there is no sense in going for elaborate multi driver setups and it sounds like the OP already has some drivers, so build an enclosure to make them as loud as possible, out of paper mache if you need to!!
And if its still not loud enough then get the youngsters to sit down the back and the oldies to sit up the front, which is probably already occuring anyway if they haven't got a PA system.
You might even want to put the driver down the back in the middle section where the voice coming from the front hasnt got enough oomph to be intelligible and "amplify and extend" that wave so it goes further down the back, with the drivers facing towards the back, mounted on the wall, say at the 75 foot marker.
That way the voice of whoever is speaking upfront is used to the best of its ability WITHOUT amplification, and the back sections can get what they need, loud, clear, non-echoey voice.
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1) give everybody a pair of headphones ... and I'm only half kidding.
2) next best, spread a zillion speakers all over the place.
Buy those $1 generic 6" "PA/background music Speakers" with the curvilinear paper thin cone and spread them so that nobody is more than 5 or 6 yards away from one, cluster them around Church columns or walls as necessary to achieve that.
For an outside listener, sound will be a reverberating nightmare (so, what's news?), but for people inside, even if surrounded by a heavy reverberant field, intelligibility comes from the *first* wavefront that reaches his ears , selecting it against later arrivals.
Out brain has a good decoder/processor built in for that.
3) line arrays and other modern solutions work in modern Protestant "Churches" (I'm referring to the type of construction) which are actually like a regular Music venue, i.e. basically a big cube, no columns to speak of, a free air path from the "stage" to the "public".
There you work like in any regular music venue.
But in a traditional Roman architecture Church, either the 2000 y.o. "T" or "Cross" shape or more "modern" (1000 y.o.) Gothic style, you have zillions of columns and arches which break any advancing sound wave in lots of small ones, bouncing everywhere , modern PA type solutions simply don't apply.
That's why you are required to ignore the full space acoustics (which are a nightmare), and provide everybody his own dedicated "mini PA" speaker only a few yards away.
As a side note, that's the reason why Early Christians (before 300 A.D.) had later to adopt *sung* services, where even the Priest "sings" what he says, once they started using the big Roman Temples.
And the Pulpit is not at the Altar but 30% "inside" where the worshippers are, to shorten that acoustic path.
These guys had not Electronics available but were quite smart.
Of course, things would have been different if Churches had been built like Greek Theaters, with perfect acoustics, but this was no practical over most of Europe and its terrible Weather conditions (compared to sunny, dry Greece).
2) next best, spread a zillion speakers all over the place.
Buy those $1 generic 6" "PA/background music Speakers" with the curvilinear paper thin cone and spread them so that nobody is more than 5 or 6 yards away from one, cluster them around Church columns or walls as necessary to achieve that.
For an outside listener, sound will be a reverberating nightmare (so, what's news?), but for people inside, even if surrounded by a heavy reverberant field, intelligibility comes from the *first* wavefront that reaches his ears , selecting it against later arrivals.
Out brain has a good decoder/processor built in for that.
3) line arrays and other modern solutions work in modern Protestant "Churches" (I'm referring to the type of construction) which are actually like a regular Music venue, i.e. basically a big cube, no columns to speak of, a free air path from the "stage" to the "public".
There you work like in any regular music venue.
But in a traditional Roman architecture Church, either the 2000 y.o. "T" or "Cross" shape or more "modern" (1000 y.o.) Gothic style, you have zillions of columns and arches which break any advancing sound wave in lots of small ones, bouncing everywhere , modern PA type solutions simply don't apply.
That's why you are required to ignore the full space acoustics (which are a nightmare), and provide everybody his own dedicated "mini PA" speaker only a few yards away.
As a side note, that's the reason why Early Christians (before 300 A.D.) had later to adopt *sung* services, where even the Priest "sings" what he says, once they started using the big Roman Temples.
And the Pulpit is not at the Altar but 30% "inside" where the worshippers are, to shorten that acoustic path.
These guys had not Electronics available but were quite smart.
Of course, things would have been different if Churches had been built like Greek Theaters, with perfect acoustics, but this was no practical over most of Europe and its terrible Weather conditions (compared to sunny, dry Greece).
Not knowing the size of the congregation, pew setup and the unknown acoustis, like rewerb time, I would consider a "behind the pew" system
With the help of the members (there must be a number of guys with table saws) you could build small enclosures for 4" speakers at minimal expense
At the same time, I would install a wire loop in a designated hard-of-hearing section
With the help of the members (there must be a number of guys with table saws) you could build small enclosures for 4" speakers at minimal expense
At the same time, I would install a wire loop in a designated hard-of-hearing section
Hi
Once one has stepped into the part of sound systems that are concerned with intelligibility and clairity, one finds that the problems in a cavernous Church are the same as in any large building.
That is, the larger the room becomes, the more air volume there is which can store sound energy, compared to the surface areas where the absorption is. That means the energy hangs around longer and when the room is large enough, it is considered a reverberant field.
While music appreciation is entirely subjective, it is easy to measure intelligibility conceptually with a long list of random words, what percentage did you understand or much more quickly with test equipment and STI or other index..
There are straight forward rules for dealing with this kind of problem which are best discovered in a Synaudcon class but I would point to A KEY rule VERY OFTEN ignored both in sound system and speaker system design and is why line arrays while widely sold and a boon to mfr’s, they are often a very poor choice in a room where intelligibility and clarity are required.
The Hopkins Stryker equation is a GREAT start;
AV: Speech Intelligibility: Gathering Additional Pieces Of The Audio Puzzle - Pro Sound Web
Best,
Tom
Once one has stepped into the part of sound systems that are concerned with intelligibility and clairity, one finds that the problems in a cavernous Church are the same as in any large building.
That is, the larger the room becomes, the more air volume there is which can store sound energy, compared to the surface areas where the absorption is. That means the energy hangs around longer and when the room is large enough, it is considered a reverberant field.
While music appreciation is entirely subjective, it is easy to measure intelligibility conceptually with a long list of random words, what percentage did you understand or much more quickly with test equipment and STI or other index..
There are straight forward rules for dealing with this kind of problem which are best discovered in a Synaudcon class but I would point to A KEY rule VERY OFTEN ignored both in sound system and speaker system design and is why line arrays while widely sold and a boon to mfr’s, they are often a very poor choice in a room where intelligibility and clarity are required.
The Hopkins Stryker equation is a GREAT start;
AV: Speech Intelligibility: Gathering Additional Pieces Of The Audio Puzzle - Pro Sound Web
Best,
Tom
180ft ceilings? Is that correct? Anyway, if you've not seen this article written by Marshall Long it may offer some knowledge and guidance.
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