Echo Problem

[gatosoft]

Hi, I am not a sound speciallist, but Im trying to solve a problem with my church sound. In the main hall we have to much echo and I cannot get rid of it. We have a mixer, two amplifier (1 for monitors and the other for the mains), 4 monitors facing the musicians and 2 main speakers at front facing the audience. The hall is completly closed with acoustical windows. How can I solve this problem, What kind of Speakers should I use?

[peza2010]

Hi, I am not a sound speciallist, but Im trying to solve a problem with my church sound. In the main hall we have to much echo and I cannot get rid of it. We have a mixer, two amplifier (1 for monitors and the other for the mains), 4 monitors facing the musicians and 2 main speakers at front facing the audience. The hall is completly closed with acoustical windows. How can I solve this problem, What kind of Speakers should I use?

 

speakers arent really your problem here. yes different setups could inprove it, but its not going to change t compltely.

acoustic tiles can be useful if placed well.. but unless you want to pay someone a lot of money, then doing it yourself, with educated guess and trial and error is the best way forward

[Simon Lewis]

Hi, I am not a sound speciallist, but Im trying to solve a problem with my church sound.

 

 

OK...

 

1) do you mean echo (a single repeat, slap back or series of repeats of a sound) or reverberation (multiple reflections that are too close togther in time to hear as individual sound, and which decay [usually] quite smoothly)?

 

2) how does the room sound with no PA system? Is it reverberant? Are there individual echoes (distinct reflections that come a fixed time later).

 

3) are you adding any effects to the sound system?

 

4) What are the walls, floor and ceiling made of? Are there any coverings on these surfaces (e.g. a floor could be concrete but with contract carpet tiles over it)?

 

5) What shape is the room?

 

6) you mention it's an AOG, but what's the worship style? Traditional with organ, or modern with drums, keys, guitar etc. How loud does it get?

 

You may get some improvement with different loudspeakers, but that isn't really the place to start. Getting the acoustics right (if there is an acoustic problem) will have far greater effect. You (or someone who advises you) needs to understand the problem. A trial and error approach to solving electroacoustic problems can be expensive and not actually bring any improvement!

 

Simon

[revbobuk]

Posting a photo of the building interior might help too - sometimes problems like this can be improved by altering the position and direction of the speakers. With you being in El Salvador there might not be a local BR member to pop in and give an opinion, but you never know!

[gatosoft]

Pic2Thanks for your reply, here are my answers to your questions.

 

 

Hi, I am not a sound speciallist, but Im trying to solve a problem with my church sound.

 

 

OK...

 

1) do you mean echo (a single repeat, slap back or series of repeats of a sound) or reverberation (multiple reflections that are too close togther in time to hear as individual sound, and which decay [usually] quite smoothly)?

After your explanation, I would say reverberation.

 

2) how does the room sound with no PA system? Is it reverberant? Are there individual echoes (distinct reflections that come a fixed time later).

It's still reverberant

 

3) are you adding any effects to the sound system?

I dont

4) What are the walls, floor and ceiling made of? Are there any coverings on these surfaces (e.g. a floor could be concrete but with contract carpet tiles over it)?

Concrete Walls, ceramic floor tiles, and drywall ceiling and at the center regular ceilling.

5) What shape is the room?

Rectangular

6) you mention it's an AOG, but what's the worship style? Traditional with organ, or modern with drums, keys, guitar etc. How loud does it get?

Modern Worship (Drums, bass, guitar and Keyboard)

 

You may get some improvement with different loudspeakers, but that isn't really the place to start. Getting the acoustics right (if there is an acoustic problem) will have far greater effect. You (or someone who advises you) needs to understand the problem. A trial and error approach to solving electroacoustic problems can be expensive and not actually bring any improvement!

 

Simon

 

Below there are some pictures of our church. Soon I will get a better ones.

 

Pic1

Pic2

[Bobbsy]

Your picture links seem to be broken but the information you've given helps.

 

You have a very reverberant room with lots of hard surfaces. Frankly the only real solution is some acoustic treatment on the walls--anything to absorb and diffuse the sound that bounces off for now.

 

This requires some specialist help. However, there's one relatively cheap/easy thing to use as a starter. Something like THIS to allow you to aim your speakers down at the congregation instead of at the hard wells should help somewhat--human bodies are fairly effective acoustic absorbers.

 

However, this is only a start. Soft furnishings and curtains and acoustic treatment on the walls will likely be needed...and, unless you have good speakers perhaps a change to boxes to ones with controlled dispersion patterns.

 

However, some specialist advice would be essential.

 

Bob

[Simon Lewis]

As Bobbsy suggests, getting it completely right would probably require some expert help from an acoustician.

 

However, if you do not have much money to spend on such a project, and you are willing to accept some compromises, it is possible to make a series of bandpass acoustic absorbers with little more than planks of timber, some glass fibre or rock wool, some thick polythene sheeting and some loose weave fabric.

 

 

[gatosoft]

 

However, if you do not have much money to spend on such a project, and you are willing to accept some compromises, it is possible to make a series of bandpass acoustic absorbers

 

 

How Am I supossed to do that?

[Simon Lewis]

[How Am I supossed to do that?

 

A broadband absorber needs a wood frame with something like 100mm of glass fibre and a limp membrane or panel behind it. Hessian or similar loose weave material has to cover the open face of the frame to stop glass fibres escaping.

 

Have a look at places like this site for standard DIY absorption panels. They will tend to absorb at mid to high frequencies though. There's some broad band versions here. Googling for DIY acoustic panels or broadband absorbers should give you some tips. If you cannot build these, try draping parts of your walls with thick curtains or drapes gathered to half width. Aim to cover at least 40% of your walls. It will make a useful difference!

 

Simon

[Bobbsy]

I once had to do a quick job of converting a conference room into a temporary studio space and we did it much as Simon suggests. We mounted battens on the walls, stuffed the space between with glass fibre batting, then covered the surface with hessian. It wasn't perfect but it took enough of the echo out of the room that we got away with it--about six months of the ITV national weather was done this way before we moved them into a "proper" studio.

 

However, there's room to think creatively as well. Your main goal is to break up hard, smooth parallel walls and keep the sound from bouncing off them. For example, my home studio back in the UK was also my library--lots of random size books on wooden shelves did an excellent job of improving the sound. Heavy curtains on the other wall completed the job and I made some decent recordings in there. Stopping echo in a live PA situation requires similar things. Short of spending a lot of money on professional treatment, you're going to need lots of little improvements.

 

Bob