Powered Amp placement in a smaller church setting

Question

I am helping to replace an audio system in a small church setting. The building is rectangular 40' wide and 65' - 70' long.

Currently the powered amp is located in the sound booth at the back of the church, along with the Mackie 1604 mixer and the wireless receivers.

There are 2 EV speakers at the front of the church.

We have two different ideas here, one group thinks the amp should be placed at the front of the church near the speakers. The other group wants to leave the amp in the back near the Mackie board and run the wires from the amp up to the speakers.

I have been searching all afternoon as to which would be a better option and work better. And I am hoping someone here can give me a good reason why we should leave the amp in the back or move it up front.

Thanks!

Answer 1

If you're running balanced line to the amp you can put it where you want.

If not, you need it near the mixer.

There's really no other consideration unless it's noisily fan-driven or you need a specific place it can get good airflow.

Answer 2

In this kind of situations it used to be common to run what was called a 100V system. The idea was to send a high voltage / low amperes on the wire and then have a transformer in the speaker to change it to the low voltage (well comparibly) / high amperages going into the speaker elements. The amp could then be hundreds of meters away from the speakers. You may still buy that kind of systems, google for "100v pa system". Otherwise, a bit larger area wires will work fine for a room like this, it really is not very long when talking PA systems.

A little word of warning about church systems in general. The main purpose is to convey a clearly intelligable spoken word. It is of course good if nmusic works as well, but it often of less priority. The interaction between the PA-system and the room may muddy this considerably unless matched to each other. I would suggest that you do a first test test with similar speakers and similar positioning as you are aiming for to verify that it will work. Maybe rent or borrow a PA-system for a day or two and do a full test concentrating on speech. There are people experienced in selecting systems for church usage and some of the speakers they use are, frankly, weird in order to get the word out. They might cost a bit to hire, but quite often ripping out a non-working system can be more costly. But do the test first, I might be barking up the wrong tree.

Answer 3

I'll echo what Tetsujin said with a bit more detail. At the end of the day, 40 ft, by 100ft is not a big space, when it comes to PA systems. The big thing you are looking for with any run in this length is simply to avoid picking up noise.

Sending a low power signal through any length of wire, unbalanced, will result in significant noise being picked up, however, if you are using a balanced signal with amps that are supporting a balanced input, then you can easily send the signal from the back of the church to the front without issue. If you have any instruments or vocals for worship, you'll already be sending much lower power balanced signals that far to get to the board anyway.

If you don't have balanced cables (TRS for your 1604) or your amps don't support balanced input, then you'll certainly want to put the amp in the back and send the powered lines to the speakers in the front.

Otherwise, you have your choice of options. Having the amp in the front will mean a bit less attenuation, but ultimately, you are not talking about a long run here. Keeping it in the back has the advantage of being able to easily reach it for troubleshooting if something goes wrong during a service.

If you can share more about the relative concerns of the two groups, that might help give more direct feedback as well.

Personally, at my church, which had roughly similar dimensions to yours, though we were setup for a wide room rather than a long one, we used the amps up front and sent a balanced signal, though a few years back, we redid the whole system to a digital board with a digital snake, so now everything is up on stage and we just have a network cable that connects back to the sound board.