Making the most (or least) of a bad room.

[Chris Nixon]

I was in a church near me tonight fixing a recording problem (signal plugged into "output" rather than "input" :yawn.

I walked in and closed the door. 3 or 4 seconds later the reverb finished decaying. It's bad enough that you can't understand someone speaking to you from more than 10M away, or AT ALL if they aren't facing you. It's hard plastered concrete and brick, with a smooth wood floor, high ceiling (estimated 15 - 20M). I'd guess it's 15 - 20 M wide and currently about 35M deep.

It seems they meant to build a church but built a gym instead.

The back wall is smooth painted wood and is on rollers so the room can be made longer or shorter.

The "PA" is 2 plastic 15 inch passive speakers by "t.Box" a cheap in-house brand from Thomman, a German retailer. The amplifier is a Thomman "t.amp" of unknown specs. They're on sticks at about head height 2 or 3M from the side walls, 15M "downstage" of the back wall. They're angled roughly 20 degrees in towards the centre.

I think it's these. the box PA502 - Thomann UK Cyberstore

There is loads of headroom, assuming the speakers can take the power the amps have. They're running their input gains about 15db too low and have the master faders at -20 for a normal speech volume. Amps are all the way up.

It was hard to actually hear the PA over all the reverb, but all their HF shelves are at at least +6, and lots are +15. I suspect they would be higher if they went any higher on a Soundcraft M12...

Attached to the wall a further 10M "downstage" is a set of 4 or 5 inch driver monacor speakers getting the same signal. A look around the amp room revealed a seperate amplifier for these but no delay unit. I turned these amps down 10db because of this. It might be an issue when people stand up but it definately helped speech.

Would the best option for intelligibility be to take one t.box, put it in the centre of the room at the front and angle it down?

Would moving the back wall back further help much? My thinking is that if the sound is going to hit it and come back I want it to go through as much air (for attenuation) as possible.

It's highly unlikely they'll be spending any money and I haven't been asked to fix it but because they occasionally ask me to come in for the odd event I'd like to do what I can at those times.

Any recommendations for a cheap but functional line delay unit? Mono would be fine.

I know it needs a total redesign of absolutely everything, but given these circumstances what would be the best deployment of what they have?

Thanks,

Chris

 

[John Halliburton]

Re: Making the most (or least) of a bad room.

I was in a church near me tonight fixing a recording problem (signal plugged into "output" rather than "input" :yawn.

I walked in and closed the door. 3 or 4 seconds later the reverb finished decaying. It's bad enough that you can't understand someone speaking to you from more than 10M away, or AT ALL if they aren't facing you. It's hard plastered concrete and brick, with a smooth wood floor, high ceiling (estimated 15 - 20M). I'd guess it's 15 - 20 M wide and currently about 35M deep.

It seems they meant to build a church but built a gym instead.

The back wall is smooth painted wood and is on rollers so the room can be made longer or shorter.

The "PA" is 2 plastic 15 inch passive speakers by "t.Box" a cheap in-house brand from Thomman, a German retailer. The amplifier is a Thomman "t.amp" of unknown specs. They're on sticks at about head height 2 or 3M from the side walls, 15M "downstage" of the back wall. They're angled roughly 20 degrees in towards the centre.

I think it's these. the box PA502 - Thomann UK Cyberstore

There is loads of headroom, assuming the speakers can take the power the amps have. They're running their input gains about 15db too low and have the master faders at -20 for a normal speech volume. Amps are all the way up.

It was hard to actually hear the PA over all the reverb, but all their HF shelves are at at least +6, and lots are +15. I suspect they would be higher if they went any higher on a Soundcraft M12...

Attached to the wall a further 10M "downstage" is a set of 4 or 5 inch driver monacor speakers getting the same signal. A look around the amp room revealed a seperate amplifier for these but no delay unit. I turned these amps down 10db because of this. It might be an issue when people stand up but it definately helped speech.

Would the best option for intelligibility be to take one t.box, put it in the centre of the room at the front and angle it down?

Would moving the back wall back further help much? My thinking is that if the sound is going to hit it and come back I want it to go through as much air (for attenuation) as possible.

It's highly unlikely they'll be spending any money and I haven't been asked to fix it but because they occasionally ask me to come in for the odd event I'd like to do what I can at those times.

Any recommendations for a cheap but functional line delay unit? Mono would be fine.

I know it needs a total redesign of absolutely everything, but given these circumstances what would be the best deployment of what they have?

Thanks,

Chris

Get rid of the Monacors, they are not helping. If you can, rent a larger pair of loudspeakers with a narrow dispersion pattern and a larger horn(which will have a lower useable frequency range than the little horn in the 15" Thomann loudspeaker). Get them up higher on larger stands if possible. Flying them high and aiming them down at the parishioners is always a good thing. The Thomann cabinets are just not even close to the right cabinet design to use in this space, they are spraying a lot of energy out far and wide and bouncing off the walls, causing a lot of the problem.

Also, is this system just for spoken word, or is there a choir or band running through the system as well? Microphone choice may help some.

The other issue is a lack of acoustical treatment in the room to reduce the amount of reverberant energy v. direct energy. This sounds like a desperately lousy room for that. Some kind of absorption panels are needed, probably some behind the speakers in the area where the pastor/choir/band are positioned, and then some along the walls in front of the loudspeakers(if they stay where they are) and up along the ceiling near the speakers(depending on the how the ceiling design meets the walls. Catch and absorb some of that early more intense energy before it reflects back into the path of the direct sound from the loudspeakers, and hopefully tame some of the reverberation in the room.

Many here will recommend hiring a consultant to evaluate the room and specify recommendations to help with acoustical treatment and sound design. I do as well, but you mention that the congregation probably won't spend money on improvements, so doing something themselves or yourself becomes the only option. There are DIY possibilities for acoustic panels as well as commercial. Be careful if you make something, use fire rated materials.

Renting other loudspeakers to experiment and show the congregation(or the church leaders) some significant improvement may motivate them to make the move to upgrade.

Good luck,

John

 

[Michael John]

Re: Making the most (or least) of a bad room.

I've worked often in a church hall similar to this, albiet a little smaller. (22x12m with a 6m high pitched roof. Walls of brick and timber and a wooden floor.) The reverb is horrible. I modelled the room in EASE once and simulated some absorption but the church didn't want to spend any money.

Echoing John's comments, the only thing I've found that works is flying the speakers about 3 to 4m off the ground and pointing them downward towards the audience.

When the room is used long, I have a centre speaker 3m out from the "front" wall and 4m up. Then a flown delay about half way down.
When the room is used sideways, I fly a pair either side of the stage and about 3m up, splayed outwards to cover each half.

The first time I did the sideways configuration, many of the old folk came up to me and said it's the first time they've been able to hear any dialog clearly in the hall since it was first built!

Best,
Michael

 

[Brad Weber]

Re: Making the most (or least) of a bad room.

It's hard plastered concrete and brick, with a smooth wood floor, high ceiling (estimated 15 - 20M). I'd guess it's 15 - 20 M wide and currently about 35M deep.

The back wall is smooth painted wood and is on rollers so the room can be made longer or shorter.

They're on sticks at about head height 2 or 3M from the side walls, 15M "downstage" of the back wall.

Is the 35m depth the overall depth with the stage? How deep is the stage, does it fill the 15m to the main speakers? Is the 35m depth to the movable wall or is it at the 25m depth?

The "PA" is 2 plastic 15 inch passive speakers by "t.Box" a cheap in-house brand from Thomman, a German retailer. The amplifier is a Thomman "t.amp" of unknown specs. They're on sticks at about head height 2 or 3M from the side walls, 15M "downstage" of the back wall. They're angled roughly 20 degrees in towards the centre.

I think it's these. the box PA502 - Thomann UK Cyberstore

Might be interesting if that is what they have since they seem to have an asymmetrical pattern, 50 degrees wide at the top and 100 degrees wide at the bottom, but with that tiny horn the actual pattern probably varies all over the place and loses much control at a fairly high frequency.

Would moving the back wall back further help much? My thinking is that if the sound is going to hit it and come back I want it to go through as much air (for attenuation) as possible.

Air absorption may be more a factor of the overall room volume, temperature, humidity, etc. but if you are actually addressing distance loss and increasing the distance keep in mind that you would be looking at the change in distance relative to the current distance, thus my question above regarding where the wall is located in relation to the overall room depth and the depth of the stage.

It's highly unlikely they'll be spending any money and I haven't been asked to fix it but because they occasionally ask me to come in for the odd event I'd like to do what I can at those times.

It's great that you want to help but watch out for people assuming that anything you do being perceived as 'fixing' everything and thus not requiring any further effort or being a failure on your part if it is not actually fixed. You might want to make sure they clearly understand and recognize that you are applying band-aids, not performing surgery.


Other than treating the room, getting the speakers up higher and aimed down to cover the audience would likely yield the biggest improvement. However, the speaker you linked does not reference and integrated fly points or provisions for flying so trying to fly it may involve an external 'cage'. Getting both the mains and delay speakers the center an minimizing overlap, if you then even need two, might also help with intelligibility.

 

[Chris Nixon]

Re: Making the most (or least) of a bad room.

Is the 35m depth the overall depth with the stage? How deep is the stage, does it fill the 15m to the main speakers? Is the 35m depth to the movable wall or is it at the 25m depth?

These are only estimates based on how it compares to a 9M by 18M room I'm in quite frequently. :razz: 35M is upstage stage wall to "downstage" wall, total current length of the room. I forgot to mention the pitched roof too didn't I, thanks Michael. Pitched on the inside too of course. It's probably closer to 10M from upstage wall to speakers actually. The stage is a stepped platform that only gets to about 1M tall at most, it's the full width. It's about 7M deep which isn't enough because they've put all the band stuff on one side. They have some more band stuff on the floor level in front of it, this stuff comes out to the line of the speakers.

But if you are actually addressing distance loss and increasing the distance keep in mind that you would be looking at the change in distance relative to the current distance

Thanks, I theoretically already knew that but totally forgot to think about it. This is what's good about forums. I'm not sure how much further back the wall goes but I'd guess there's at least 10M left in it, which would add 20M to the path.

Other than treating the room, getting the speakers up higher and aimed down to cover the audience would likely yield the biggest improvement. However, the speaker you linked does not reference and integrated fly points or provisions for flying so trying to fly it may involve an external 'cage'. Getting both the mains and delay speakers the center an minimizing overlap, if you then even need two, might also help with intelligibility.

Given that these are only £150 speakers the cost of flying them might not be as much value as it would if the speaker was any good. They might spring for a taller speaker stand(s?) with a tilting top on it.

When the room is used long, I have a centre speaker 3m out from the "front" wall and 4m up. Then a flown delay about half way down.
When the room is used sideways, I fly a pair either side of the stage and about 3m up, splayed outwards to cover each half.

The room will be used long, they've already got an installed stage and multicore. If they'd be OK with a speaker on a stand in the middle of their seating area that could work. 6 - 9 seats worth should be enough space. And gaff tape for the cable. :razz: Is there a cheap but serviceable delay unit that could be used for this?

Get rid of the Monacors, they are not helping

I took 10dB off them last night, haven't heard the results with the room in use though. I'll take them down the rest of the way if it hasn't caused any problems. My only concern right now is that the main speakers at the front may not reach the people at the back when everyone stands up to sing. I did it anyway because the vast majority of the use is for speech to a seated audience. This wouldn't be an issue if the mains were higher.

Also, is this system just for spoken word, or is there a choir or band running through the system as well? Microphone choice may help some.

Both, someones sold them a load of ATm33a cardiod condenser mics (or it might be the newer model of that, but it's basically the same mic.) I know the mic and like it, but the pattern is a bit wide. Combined with the fact that they're micing the pulpit speaking person with a gooseneck that's too short there's probably a lot of below-unity-gain feedback being caused by and adding to the reverb. In fact if you have someone walking around the empty room about mid way back and the pulpit mic is turned up, you can faintly hear their footsteps if you stand near the PA.

I think they have an SM58, if I can get them to try this as close to the source as possible that should help, a bit. It wouldn't look as nice though. :roll:

Last time I was there the soloist for the choir used the SM58 and they put 2 ATm33a's in front of the choir as a whole. Thankfully the soloist didn't sing loud enough for the comb filtering to be a problem. ~:-D~:grin:

Most of the more contemporary type stuff is either DI'd (digital piano and e-drums) or it's a guitar amp.

It's great that you want to help but watch out for people assuming that anything you do being perceived as 'fixing' everything and thus not requiring any further effort or being a failure on your part if it is not actually fixed. You might want to make sure they clearly understand and recognize that you are applying band-aids, not performing surgery.

It helps a bit that this time last year I started upgrading the system in the church I go to and made a large improvement, but at a relatively large cost. The 2 churches are somehow related and share preachers and ocassionally borrow tech people.


Thanks for your help,

Chris

 

[Randy Gartner]

Re: Making the most (or least) of a bad room.

Changing speakers and aimimng them at the audience instead of the back wall will help.I have also found that going to a good headset type mic will help with intelligitbility. But with a 3 to4 second decay, they need to make some changes with acoustic treatments.Carpet on floors and drapes on back wall would help.But if they don't want to spend any money there's nothing you can do.You can't fix something with nothing!

 

[Jeff Babcock]

Re: Making the most (or least) of a bad room.

The reverb is horrible. I modelled the room in EASE once and simulated some absorption but the church didn't want to spend any money.


The first time I did the sideways configuration, many of the old folk came up to me and said it's the first time they've been able to hear any dialog clearly in the hall since it was first built!

It blows my mind how some churches with really bad rooms don't want to spend money on something that I would consider pretty crucial to their modus operandi - ensuring that their message is heard clearly. I have seen some use assistive listening systems to help overcome this, when they could have spent the money on acoustic treatment which would benefit everyone, not just a few.

 

[Chris Nixon]

Re: Making the most (or least) of a bad room.

It blows my mind how some churches with really bad rooms don't want to spend money on something that I would consider pretty crucial to their modus operandi - ensuring that their message is heard clearly.

Maybe they like the fact that everyone hears the message multiple times...

From the PA, from the left wall, from the right wall, the floor, the ceiling... ~:-D~:grin:

Chris

 

[John Halliburton]

Re: Making the most (or least) of a bad room.

Maybe they like the fact that everyone hears the message multiple times...

From the PA, from the left wall, from the right wall, the floor, the ceiling... ~:-D~:grin:

Chris

The problem is it gets less articulate at each reflection back into the direct sound...

I agree with Brad, you need to couch any work you do in terms of "making improvements", not "fixing". There is a lot of work needed in this situation.

As for the choir mic set up you described, as long as you observe the 3:1 rule with mic distances(or greater), the comb effect should be minimal. Getting the pastor on an SM58 up close, if that is the only alternative to a ear mic(hardwired or wireless), then it too should help.

Taller stands should help, but you may not need a tilting feature, as the little horn has enough vertical dispersion to compensate a little anyway. Flying them and aiming down will be a larger undertaking, but produce the best results, and if you can go that route, the rigging infrastructure should be designed to handle better loudspeakers down the line, which won't take much at this level(no offense intended).

Sound absorption to tame any of the room's reverberant field would be high on my list-as I said, there are DIY solutions available, and if there are folks in the congregation with some carpentry skills, might be a solution. Otherwise, start a fundraising campaign for some acoustical treatment, larger speakers, and rigging!

Again, good luck.

Best regards,

John

 

[Chris Nixon]

Re: Making the most (or least) of a bad room.

As for the choir mic set up you described, as long as you observe the 3:1 rule with mic distances(or greater), the comb effect should be minimal. Getting the pastor on an SM58 up close, if that is the only alternative to a ear mic(hardwired or wireless), then it too should help.

I didn't mean between the 2 choir mics but between the soloists mic and the choir mics, I know this can be a problem because I did it a couple of weeks ago and a different church. :lol: The first couple of words sounded like a really bad MP3 until I got the choir mic down. ...not really a bad thing I suppose as I'm less likely to do that again...

Thanks for the suggestions. I'm not going to invest too much of my time into it unless I'm asked about it but I'll have a much better starting point. I'm not there more than 3 or 4 times a year so I don't have to suffer it, but I look after the sound in another church which has close links to the one with the problem. Because I recently improved it I'd probably be the first person asked about the other one.

Chris