Venue wider than it is deep

[richardash1981]

On Sunday we tried re-arranging the furniture at church to reflect what the first-draft plans for dividing up and refurbishing the big church building might look like. This ends up being less than half the existing length, but the same width. The nice thing is that the congregation end up sitting near each other, rather than spread out miles apart (they could move, but habit of a lifetime ...). Less happy was their positioning vs. the existing (column) PA speakers. Because these are hung on the side walls at the front, and pointed down the length of the building, they ended up missing where people were sat pretty much completely, instead mostly firing past the back of the congregation. I walked round a bit, and the PA was louder behind them than anywhere with seats out. I didn't get any complaints (no heating blowers running, loop on as normal), and of course being much closer to those leading at the front, there is less need for amplification (what a new ceiling does to that is another question).

Anyhow, the question it all raised was, how do you place speakers for a room which is 10 wide and only 8m deep (approximately) including the raised area at the front (say 2m) where the service is being led from? Apart from one hall with rather sub-optimal in-ceiling speakers, I have no recollection of other installations for such a space. I could make guesses, but wondered if anyone could share successful (or not) ideas.

In general, gain before feedback has always been the limiting factor with the current speakers and building, the problem being mostly to get talkers over the noisy fan-blown heating system (which the refurb should do away with) to an elderly congregation (which it hopefully won't!).

[James]

Is this a permanent install or one that needs to be rigged/derigged on a weekly basis. 
What is the content - is this vocal only for readings/sermons or do you have a full on worship band? 
Have you considered a specialist consultant to advise on best system for space and your requirements? 

[Robin D]

Many factors at play here, but usually if in a short but wide space, get the speakers as close together as practical. The audience will struggle with deciphering the spoken word otherwise. Often a single speaker works better. Column speakers are designed to project a narrow vertical soundstage over a long distance so the sound level can often appear louder at the back. 

I would try moving one to near centre if possible and using just the one. Asa trial, leave one where it is and just turn the other off.  It may also work better in that space if you mount it horizontally to provide the spread of width rather than depth. Reducing the number of active drivers in the column may also help if you know enough about the design to do so safety. 

I concur with the view from James that you may need a specialist in to advise.

[sandall]

(Assuming it's possible to mount one in the centre) a single column in unlikely to cover more than the centre of your congregation (mounted on its side it will only cover a very narrow area!!). Columns follow the normal laws of physics (inverse-square law & all that), so if they sound louder at the back this has to be a function of the building structure & the direction of fire, rather than a property of the speaker.

[Stuart91]

If this is a full refurbishment of the building, then the cost of a (properly designed and installed) PA system will be little more than a rounding error in the overall bill. 

However you might be battling against the mindset which many churches have that audio is something they expect volunteers to conjure up on a shoestring. (Funnily enough, they rarely take the same approach to, say, central heating or electrics...)

What's the room like? Is it a modern building or a traditional gothic pile? Ceiling height is going to be crucial here. As others have suggested, a centre cluster (or single speaker) will almost certainly work best with the seating layout. Whether it can be accommodated physically is another question entirely. 

Depending on denomination you may have to gain approval from a church committee higher up the chain - might be worth bearing in mind. 

 

[DrV]

3 hours ago, sandall said:

Columns follow the normal laws of physics (inverse-square law & all that),

Is it not also the case that a column's radiation pattern is similar to an optical slit which (perhaps counterintuitively) spreads more in the direction perpendicular to the long dimension? Laying one on its side would, therefore, make its coverage more vertical than horizontal. Just interested from a schoolboy physics point of view.

[sandall]

Indeed. Confusingly, this also applies to outdoor horn-flares, though you almost invariably see them mounted horizontally, probably because of how the brackets are attached.

[Simon Lewis]

The types of column speaker usually encountered in churches only approximates the inverse square relationship with intensity over a certain portion of their bandwidth. 
Depending upon the architecture, layout and any ecclesiastical constraints, I would probably look to either fly something centrally or if placement was really constrained consider discreet stand mounted speakers either side of the front area with good wide dispersion. Martin Audio CDD boxes seem to work well in this application...

[Stuart91]

14 minutes ago, Simon Lewis said:

 I would probably look to either fly something centrally or if placement was really constrained consider discreet stand mounted speakers either side of the front area with good wide dispersion. Martin Audio CDD boxes seem to work well in this application...

Another vote for CDD - we've had very good results from them in similar situations. 

[kerry davies]

Just like everyone else I suggest getting the sound sources closer together. Also this may be egg-sucking but make sure you are playing recorded stuff in mono. I used to DJ in a large pub and the difference between mono and stereo was incredible.

[sunray]

19 hours ago, sandall said:

Indeed. Confusingly, this also applies to outdoor horn-flares, though you almost invariably see them mounted horizontally, probably because of how the brackets are attached.

In my experience rectangular horns are very different to columns. I've been using both for years and confirm columns work as described above.

However the experience I have with horns is they require mounting horizontally. My own stock of horns was initially long 42" round which provide amazing projection, for smaller events I obtained Eagle HDB12 re-entry (300x150mm) and used them horizontally on T bars. However I made up fittings for the latter to mount a pair vertically with a 100V transformer and scaf pole stubs top and bottom to make them stackable.

Excuse the sketch:

Made it a very neat and compact unit and when swivelled together  basically a 1 foot cube. I very soon found the horizonal dispersion was narrow, which was great for GBF in the arena for example but for 360 cover from a central point I found they created major gaps in coverage I had to use more speakers (and hence more power) which gave significant rise of SPL at the speakers.

I didn't use the brackets for long as the convenience didn't outweigh the poor performance, as it happens someone else saw them at an event and enquired where I purchased them, being dissatisfied I found myself offering them for sale, he fairly soon found found the same issue (I think he was using the bigger HDB16 Eagle speaker). 

The other rectangular horns I have significant experience with are Atlas CJ46's; substantial fibreglass horns about 600x300mm with 1 3/8" thread and have always found the vertical adjustment to be more critical than the horizontal, intelligible sound under their axis nigh on cuts off as approached rather than fades as you move off sideways.

If working under cover (Stadiums) I avoid round horns to reduce reflections off the roof.

I've handled a few other rectangular speakers but mostly smaller units and usually not in situations where I've noted lack of coverage.

I'm only putting forward my personal experience and in no way disputing that other horns behave differently, I've noticed HF horns in cabinets are sometimes vertical and sometimes several mounted in 'bay window' format.

[sunray]

3 hours ago, kerry davies said:

Just like everyone else I suggest getting the sound sources closer together. Also this may be egg-sucking but make sure you are playing recorded stuff in mono. I used to DJ in a large pub and the difference between mono and stereo was incredible.

I spent a year or so doing nightclub work and it always amazed me how many ran in stereo and how many visiting DJ's automatically checked the pan/balance to ensure it was, one even walked off before her set when she found it was mono.

I'd love to know how a club is supposed to function correctly in stereo and how the 2 channels are supposed to be distributed around the plethora of speaker zones.

[J Pearce]

I can think of a few potential approaches, all improved by flown speakers rather than on sticks.

Are all the seats facing the stage in one line, or are you setup on 3 sides?

If I were feeling fancy I might even be tempted by a split rig with one system for speech and another for music.

(I often find a system designed for high intelligibility gives a lacklustre un-enveloping sound for music)

 

[bruce]

7 hours ago, J Pearce said:

If I were feeling fancy I might even be tempted by a split rig with one system for speech and another for music.

(I often find a system designed for high intelligibility gives a lacklustre un-enveloping sound for music)

 

That's pretty much a standard design in University lecture theatres(*) - lots of ceiling speakers, with delays, so speech is audible throughout, but not overpoweringly loud at the front. And a secondary system with conventional speakers each side of the screen, for higher quality "programme sound" from video sources etc. Of course, these days they'll all be fed and delayed from the same digital matrix, and you can design some "bleed" from one into the other, but the basic principle has been the same for years.

 

(*) University lecture theatres and churches have a lot in common. Someone at the front doing all the talking, and the audience sitting listening. I could go further, drawing comparison between ministerial robes and academic gowns...

But this "Dick Turpin" style of presentation (where you "stand and deliver") can't be the most effective way of getting a message across. If it was, the marketing people would have picked up on it years ago 🤪

[richardash1981]

Thank you for lots of response to this.

Content is mid-way - it's more than just readings / sermons, because we have 2/3 singers on microphones to lead the singing (started when it was all we could do post lockdown, and it's stuck) but don't have a full worship band - the pipe organ and piano are acoustic (mic'ed for streaming only). Occasional video playback, but no-one is going to design around it.

Hopefully it can be a fixed solution - we own the building (to all intents) but the space will be used by other users through the week, so fixing things to walls / ceilings is a lot more attractive than anything loose. The building is a 1956 concrete and brick box, and there isn't a hierarchy (United Reformed Church) so there is considerable freedom to do things (the overall project will get a high-level sign off regionally). Ceiling height is to quite an extent in our gift - at the moment it's 33 feet to the ceiling (as tall as it is wide). We expect to put in a lower ceiling to make the building workable, the current concept shows the new ceiling at 5.5m (we also need to be able to do projection with people standing).

We have some freedom about seating (because it will be chairs put out for each service), last Sunday's trial was with chairs in a part-circle, but all faced up to the front of the building - the raised area is full width, so it's not a thrust stage setup.

Funding the work is still a major challenge, and there is an urgent need to tackle energy costs and a full rewire - things that can be delayed without increasing the costs radically are likely to be sought out. Getting an acoustic consultant in is going to be important, but there won't be an appetite for starting over again for it's own sake. I also don't want to be in the position of not knowing whether a solution is plausible until it's been installed - we are still trying to locate an architect we trust on the building design, so employing an expert to some extent transforms the problem into finding a good one to engage. I can't say I've seen many church systems locally which impressed me either (and the ones which did turned out to mostly be in-house jobs).