OT: Audio nightmare in an old church

dxdy wrote on 1/6/2012, 11:45 AM
I have run into a presentation venue problem, and I would be very grateful for any advice anyone can offer.

I am almost done with a 30 minute video for the local historical society. It is an interview with four gentlemen who started collecting endangered buildings and moving them to a donated village site some 40 years ago. The sound I collected is good - it sounds fine in a living room, but it is to be presented in an old church that is an echo chamber, and the deepest voice is unintelligble.

The room is about 30' wide and 40' long, with an 18' ceiling and a small choir balcony at the back. There isn't a scrap of cloth or sound absorbing material in the place, including the hardwood pews.

Last night we did a sound check. We can understand the 2 lady interviewers, and 3 of the 4 gents pretty well. The 4th man, who is in his 90s, has a basso profundo voice, and it comes through totally muddled. Last night we didn't have the video projector, so there were no hints from lip reading.

Since there is no sound system in this 165 year old building, I took in 4 pairs of computer speakers (2.1 systems, reasonable quality). We tried one system, then two systems; we moved them around, and up onto the balcony; we tried different speakers; we turned the bass all the way down and the treble all the way up... in short everything we could think of. (I am using my AT88W wireless mic transmitters/receivers to connect to the set I put in the front of the church. While the AT88W isn't the top of the line, it doesn't appear to be contributing to the problem, from what I can hear). I played the intro music as well, and it sounded okay,

I know that some venues cannot be fixed (the Detroit Symphony's "new: marble barn built in the 50's, Ford Auditorium, was so reviled it has finally been torn down) even with baffles and bass traps and sound absorption panels, even if we could afford to put them in. I am wondering if there are some tweaks I can do to the audio to help this out. If driven to it, I will do subtitles for the critical areas, but I would rather not get into that.

Thanks in advance,

Fred

Comments

Chienworks wrote on 1/6/2012, 12:02 PM
Well, keep in mind that it will be better when the room is full of audience members and their winter coats, hats, and mittens. That may be enough to push it up over the edge of intelligibility.

When i had to run sound for a concert in a gymnasium i asked everyone involved to bring a big blanket and i bought a case of duct tape. While i was setting up equipment the other dozen people each hung a blanket on the walls. Even though we only covered maybe 3% of the surface, it was enough to cut down on secondary echoes and made a huge difference.
LarryP wrote on 1/6/2012, 12:12 PM
Fred,

Some suggestions.

Control the pattern from the speakers to just the seating area. Your best bet would be to rent one of the newer stick speaker arrays made by Intellivox, Fraizer, Bose and a host of others. Your renter would need to be technically savy as one size does not fit all.

Move the speakers as close to the seating as you can. As you noted being loud only adds to the reverberation and not intelligibility. As you move further from the sound source there is a point called the critical distance where you are hearing more reverb than direct sound and intelligibility is gone.

In extreme cases some churches have resorted to under pew speakers every few feet. Perhaps you can string a bunch of speakers along the aisles and with enough speakers you can get by without multiple delays.

You mentioned the lower voice ranges are more problematic. In hard walled spaces, like churches, the reverberation time goes up as the frequency goes down. While the talker may not sound quite like himself some healthy low end roll off will help.

Lastly, and perhaps difficult, is to encourage everyone to sit up front close to the speakers even if you have to rope off the rear rows.

Hope this helps.

Larry
RalphM wrote on 1/6/2012, 12:13 PM
Sounds like you've found the resonant frequency of the space in the elderly gent's voice, or perhaps the mids are being depressed for some reason..

The fact that it's a preservationists' group conflicts with doing much for sound deadening (even if that's possible).

Putting the sound clip in SoundForge and playing it in the church while trying various equalization schemes could be useful.

What about (with the elderly man's permission) pitch shifting his voice for this particular presentation and making that known. It may get you away from the offending frequencies.

RalphM
TheRhino wrote on 1/6/2012, 12:33 PM
Before digital we used to use a white noise generator to set the EQ for churches with hardwood floors, ceilings & pews. With digital you can make many more presets and change them on-the-fly when more people are in the room. The room will sound totally different when it has more people. This can make it better or actually worse.

My suggestion is that if you have time, add the words to the lower 3rd just like they do for reality TV. The reality TV guys are always dealing with poor sound sources and their solution is to add the words to the lower 3rd. This way those that can hear the low voice can just listen and those who cannot make-out what he is saying can read. If there is not enough time to do this, then you will just have to have multiple EQ settings handy and switch through them (quickly) once the room is full.

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dxdy wrote on 1/6/2012, 5:14 PM
Thank you for the suggestions. The apply EQ solution sounds like the best one at this point, I don't think I can subtitle the entire presentation in time. (Unless someone know if there is a Vegas plugin that will create the subtitles).

I never knew that Windows Media Player 11 had a Graphic EQ built in - right click on the player, select Enhancements and there it is!

Early experiments with the EQ indicate it might be just what the doctor ordered.

D