CHCC Renovation: Main PA and Lobby

Because of the cool rigging bar, we only needed two pick points to fly the array and get the angle we needed. Gotta love good hardware.

Because of the cool rigging bar, we only needed two pick points to fly the array and get the angle we needed. Gotta love good hardware.

By now it should not be news to anyone that we put in a Bose RoomMatch PA in Coast Hills. I have taken no small amount of flack for that decision, but I stand by it, especially now that we really have it dialed in. As I’ve said before, there are other PA’s that we could have used, but none fit the budget and provided the directivity control RoomMatch does. And in that room, we really need control.

Asymmetric and Symmetric Boxes

As far as I know, we are one of the first installations to use both types of boxes in the arrays. Now, I should point out that RoomMatch may look like a line array, but it’s not. It’s billed as a Progressive Directivity Array. That means each box covers a specific part of the seating area. There is some combining at lower frequencies, but for the most part, the boxes don’t interoperate much. 

Because of that, we were able to mix and match boxes for a very specific design. I wanted to provide some sense of stereo imaging across a wide chunk of seating in the middle, and keep as much sound off the walls as possible. To meet those goals, we used boxes that were narrow on the outside and wider in the middle at the top of the array. The arrays are mirror imaged and the coverage is indeed pretty tight.

I do love a good rack. Amp rack, that is...Get your mind out of the gutter.

I do love a good rack. Amp rack, that is...Get your mind out of the gutter.

Keep The Colors Straight

Apparently, when I wired up the arrays, it was dark and I was tired. I inadvertently wired a few NL4s wrong and we had some phase issues initially. But once we got that sorted out and began the tuning process, it was all fun. 

A couple of guys from Bose came down and started taking measurements throughout the coverage area. They averaged those together and we came up with a room curve. Interestingly, the curve they came up with was shockingly similar to the one I put in using a LAMA transfer function with the measurement mic at FOH. 

We ended up with about 4 filters in the system, and two of them are there to tame room anomalies. Otherwise, the system sounds really good out of the box. We did a little gain shading in the amps to dial out some summing that was happening with the LF elements in the arrays, and to compensate for the air loss at the HF end. But otherwise, the system is pretty flat. 

Stereo Imaging for Days

I really wanted to have an LR system, but didn’t expect to get great stereo imaging. I was surprised to be wrong on this point. Throughout almost the entire center four sections and much of the back outside sections, there is an excellent sense of stereo. We played a bunch of tracks through the system and each time we kept looking at each other saying, “Wow, the stereo field is amazing!” It’s some of the best I’ve heard in a live PA. 

But vocals image right in the center where they should and speaking sounds fantastically present. So I’m very pleased with that. Time will tell if they really utilize the stereo image as well is can be, but it’s nice to have it available. 

This is a terrible photo of the subs. but you get the idea.

This is a terrible photo of the subs. but you get the idea.

Big Bottom

The system also has four dual-18” subs in a cardioid pattern flown over the center of the proscenium. They are in a 2x2 arrangement and once we got the timing right, it’s pretty remarkable how little low end there is on stage. But throughout the whole seating area, there is plenty. We ended up dialing those back a little bit because Coast Hills has never been thumping the bass. There’s headroom there, however, should the new style of worship desire more bass. 

Because the main boxes go down so low, the subs are really only working at the very low end, just like they are supposed to. Off hand, I don’t recall where they are working, but I believe it’s from about 30-90 Hz. 

Good Lobby Sound

For the last 5 years I’ve been frustrated by the sound in our lobby. It was terrible, really. We had a bunch of ceiling speakers mounted in the walls. Under the best of conditions these won’t sound good, and these were not good conditions. 

I spent a little more money in the lobby than I ordinarily would have, but I’m glad I did. We hung four RMU208 Utility Speakers from Bose up in the corner where the wall meets the ceiling. The RMU208 is a dual 8” plus a horn configuration, and it’s driven by a PowerMatch 8250. The 8250 puts out 250 watts into 8 channels, so each speaker is powered individually. I went with 8 channels because someday, they want to blow the front of the building out and put speakers out front. So they have 4 channels to expand into. 

I didn’t have time to do any tuning of the lobby speakers, but I thought they sounded acceptable out of the box. At some point, I want to go in and play with the Smaart rig and tweak them a little bit, but for starters, it works. My choice of Bose speakers for the lobby was based on the idea that I wanted them voice matched to the mains. As you walk in from outside into the lobby, then into the sanctuary, it just keeps getting louder, but it sounds the same. I think we hit that goal. 

Overall, I’m very pleased with the system. It has enough headroom to get really loud if they want, but it sounds clear at lower volumes. It’s very present without being harsh and has a nice, warm low end that doesn’t mask the midrange. And the lobby sounds good. That’s a win in my book.

Roland