IB Sub for Church Organ

[barrylumpkin]

I've digitized our old analog Rodgers electronic organ at church using www.hauptwerk.com/ with this sample: www.milandigitalaudio.com/skinner.htm. The sound is better than the old analog organ, but we're using the old Rodgers amps and speakers leaving much to be desired.

I'm studying the possibility of adding new high quality speakers to our system. There's a closed attic area above the two organ chambers; so, it may be possible to use with an IB Sub. We have a 200 seat auditorium with good acoustics.

How many speakers do you think it would it require? Is the IB something I should consider using? What's the downside? Should I stick with a typical organ subwoofer?

Tuning a subwoofer to the room won't be a problem. The Hauptwerk software will allow for each note's volume to be individually adjusted.

Before I ask the church leaders for permission to remove a chunk of the ceiling, I thought I'd better get some good opinions.

[chrisbee]

What is your likely budget? I love organ music but am not remotely qualified to suggest how big an IB you will need.

IBs can go very loud above 40hz but need lots more cone excursion to go lower. Keep doubling cone excursion to go lower and louder at the same time. You either run out of safe excursion at some point. Or you have to keep adding drivers to stay safe. More cone area means less excursion to play the same note at the same level. Adding more cone area costs lots more money.

It probably comes down to economics in the end whether an IB is a sensible choice:

The boxes (compact manifolds) for four 18" drivers are cheap enough to make. As they will be invisible there is no point in expensive finishes. This can save some money. As will the DIY nature of the project.

Let's say Fi IB318 drivers will cost in the region of $1000 for four including all manifold materials and cabling.

Imagine you need (say) 16 drivers and four manifolds to make any real impact. You are up to $4000 without amplification.

Add another $1000 for four Behringer EP4000 power amps. Better amps may promise better reliability in a "professional" installation. If you must then you can easily quadruple the price for quality amps.

You might easily spend $5000 minimum on an IB and still need more to safely reproduce the big pipes at reasonable volumes throughout the auditorium.

Go too loud and too low at the same time and you might damage the drivers. Though you could fit a high pass filter to keep things to a maximum, safe, cone excursion limit.

Remember that the IB is only a subwoofer so you need speakers as well. Or a crossover to the existing speakers to save them from trying to play too low.

Not much help I'm afraid. But, it will give you a ballpark figure to consider whether it is even worth continuing with an IB project.

[ThomasW]

200 seats is insufficient info....

What are the dimensions of the room? What are the average SPL of the old organ?