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[Kristian Stevenson]

We have a "contemporary" service that is thankfully growing so much that in a few months, we won't be able to fit in our current worship room. Our only other large room is the gym. Acoustically, it's a nightmare but its all we have for the space we need. We will be in the market for some portable speakers to use for this service. I don't have a budget yet, I'm just trying to figure out what it will take so I can know the figures when the time comes.

I am wanting to go powered to keep it simple for the volunteer setup/tear down crew. I was looking at 2 different setups and want some opinions: 2 QSC KW152's for the tops and 2 KW181's for the lows. OR 2 JBL PRX625M tops with 2 PRX618S-XLF bottoms. I have heard QSC's K10 which sounds quite impressive for such a small cab.

Music-wise, the service mainly consists of various vocalists, tracks/loops, keyboard, guitars, and bass guitar (no dedicated drummer yet). We will setup length way in the gym. It's a standard 50'x94' court. This rig will also be our "portable" system to be used outdoors so versatility is a must.

What do you guys think? Any other recommendations?

[Frank DeWitt]

Re: Portable System to be used in gym I would test drive what ever you look at. Gyms are hard. We set up with two speakers that are a bit bright (lacking in base) and point them down court, but at an angle, not at the opposing wall. and as high as is safe on sticks.

Speaking of sticks, I would rather use non powered speakers. One less cord across the floor and up the stick. Less power cords running around. Easier to gaf tape to the floor.

And they are just a bit lighter.

In the end a powered speaker has two cords. An amp and speaker has 3 total but two of them are a lot shorter.

[Brad Weber]

Kristian Stevenson wrote on Sat, 20 November 2010 20:23

What do you guys think? Any other recommendations?

Yep, try to fix or at least control the acoustical nightmare you noted.  Whether it's installed wall panels, baffles, banners and so on or temporary heavy drapery, often one of the best investments is to first try to tame the room.

[Stephen L Gregory]

I am very interested to know whether you have made any decisions about your new PA.

We will be planting a church (<100 to start with) in a gym in Feb, and are thinking through the same issues.  For us, the key point is that everything has to go in and come out every week, so flying a centre cluster or treating the walls are not an option.  Maybe we need to invest in a big carpet, though!

My expectation is that the main problem will come from the bass.  I was thinking of sending v-drums and bass to a single head-high forward-facing monitor (Mackie TH15A?).  Maybe we'd get a better sound with them just out of FOH, but then they'd need monitors (= more stage noise as IEM is not an option at this point). I just hate to think what will happen if I let the bass player bring his 400W crate pointed at his knees...

Currently I'm thinking vox, keys and guitars going to two QSC K12s for FOH. Foldback only for keys and vox, kept as low as possible. Sincere exhortations to guitarists keep it down.

The KW152s that you mentioned are over 60 lbs, and I'd not be keen to be lifting them head-high each week.  Same for the JBLs, which also have a 90 degree spread that I'd be worrying about.
I'm looking for light actives that don't spread too wide, with the intention of minimising wall reflections.  Of course if you keep it off the walls you tend to get not-ideal overlap in the middle, but that's what aisles are for, right?  

[Brad Weber]

Just remember that the pattern or "spread" of 60 degrees or 90 degrees is simply a nominal value where the overall level is 6dB down compared to on axis.  It is not exact and it will vary with frequency, in some cases varying greatly and typically having less control at lower frequencies that with physically small horns may extend well into the speech range.

Also keep in mind that speakers have a vertical pattern as well.  In a permanent install you can often gain multiple benefits by mounting the speaker higher and aiming it down toward listeners.  That may not be feasible when using a portable system and thus addressing the vertical pattern can be one of the challenges with portable systems.

I'm not real clear on what you plan for some of the system.  You mentioned K12s for FOH vox, keys and guitars but what about the electronic drums, the bass and the bottom end of the keys?  You also mentioned a single "foward-facing" monitor but which direction is forward in that case and would this be the only monitor?

In a more general context, how do you plan to configure the space?  Will you have a stage?  Where will it be located?  And while it would be significant extra work, why couldn't you use pipe and drape each week or even work with the other gym users to find some acoustical treatments that could be implemented?  And do you have all the power you need where you want it in order to support the powered speakers, the backline and the FOH mix location?


Kristian,

If you are setting up lengthwise, think about whether you really need stereo or speakers on each side of the stage.  I think people tend to default to speakers to either side of the stage just because it's what they see a lot but if you can't get good stereo for most of the listener area, the imaging and localization either aren't good or aren't that important or if it results in poor intelligibility, then why not consider a single speaker location?

[Stephen L Gregory]

I take your point about spread.  I'm not expecting miracles of pointiness from a K12, but I'd hope that at least the tops were not splashing off the walls too much.  The idea would be to mount on poles as high as practicable (7'?) and angle down for what it's worth.

If I knew of a comparable system with better pattern control I'd seriously consider it, but down at the budget end of the market tight patterns don't seem to be very common.

I am conflicted about what to do with bass.  One argument says buy the best FOH tops and subs you can afford and do your best to keep stage noise low by minimal monitoring (instruments use their own amps and I plead with them every week to turn them down).  

An alternative, which may be badly flawed, is to say: vox and keys get foldback (2 channels) from some so-so wedges we have, and we set up a head-high 15" monitor centre stage rear facing the audience between drums and bass.  The idea being that this pretends to be a real drumkit keeping everyone together, but is hopefully more controllable.  Whether I would be able to bring this up enough to add punch to the mains I am not sure, but the rhythm section should be happy enough with it breathing down their necks. I want to DI the bass and keys so the only amp on stage would be guitar.  Then if there's a stage noise problem it's either him or me!

The gym is standard basketball sized with no bleachers or actual stage of any sort - a cinderblock shoebox (ack!). I was planning to run lengthways to avoid the back wall, but we could go either way.  Pipe and drapes is a good idea.  I want to limit the amount of gear we have to haul, but it would be worth trying at least to see if we really notice the difference.

I'm hoping power shouldn't be an issue with what I'm planning to run here, but I need to check that, for sure.

I wasn't planning to run stereo, but I'm intrigued by your suggestion that Kristian consider one speaker location. Isn't that disconcerting for listening to voice unless they are central (and flown)? Maybe if you delay them just a bit and keep the volume down you can get away with a Haas effect?

[Brian Ehlers]

I don't know if disconcerting is the right word.  People seem to adapt rather quickly to having the sound come from a location other than the source -- as long as they can hear everything OK.

The bigger problem with using a single speaker (presumably on one side) is the variation in coverage.  Some people will be hearing a lot more sound than others.

While my church was undergoing renovations one summer, we held our contemporary services on a gymnasium floor.  I used a single JBL Eon-15 about 8 feet up and angled diagonally to cover 250 people.  Far from ideal, but I never had a single person complain.  I used a similar set-up in our 50 x 70 fellowship hall before we installed a system.

[Brad Weber]

I think it depends on the situation.  If you have a fairly narrow stage and either nobody close to the stage or those close to the stage getting much of their sound direct from the stage, then localization via a stereo system may be of limited application and may be better in terms of intelligibility.  Just another one of those situations where one may have to consider the pros and cons of various factors and decide which potential solution offers the best overall result.

I do think that people too often default to left and right speakers without considering the actual result for the listeners.  If you're addressing imaging or localization then that involved the relative levels and timing between the left and right signal at the listeners.  It can be difficult to get a system that provides close to the same relative level and timing relationships for all of the listeners and the reality is that many "stereo" systems sound dramatically different at different listener locations.

Think about listeners near the stage and off to either side that due to their distance to and the levels from the speakers may tend to perceive the sound as coming from one channel or the other unless panned hard to one side.  Or those located further who may not only perceive a greatly reduced difference between the left and right signal but for whom "left" and "right" represent a much smaller physical differentiation (just think of the angle from the listener to the speakers and to the stage and how it reduces as you move further away, thus reducing the variation left and right represent).  Add to that the effect of reflected sound.  If you have a stereo system, try walking your room with a mono source panned different amounts toward one channel and see if the resulting perceived location varies.  You may find that what you hear at FOH is not what some areas of the seating hear.

I'm not at all saying it is never beneficial, but just like many other factors one has to look at 'the big picture' and balance all of the potential negatives and benefits in whatever manner best serves the application.

[Kristian Stevenson]

Those are interesting ideas but with a portable system that is not flown, it wouldn't be ideal to have a center cluster as it would block sight lines. I have never thought about having a cluster on one side of the stage though. I don't know about the other guys but most of my sources would be mono anyways. I guess I would default to a Stereo PA mainly for coverage sake as we would have 2 sections, left and right with an isle down the middle. Our main problem is the small PA we installed in the gym is not set up length ways but width ways. Here's a picture. We are wanting to setup for the service length ways. Opposite of how the chairs are set now.


As you can see, If we were to just use the gym PA we would be hitting the audience in the left ear only with sound. That is why I want a separate system to use for this service and so we can have a portable system for other events. This is where the flexibility part comes in.

[Jonathan Johnson]

If sight lines with a center cluster on stands are an issue, how do you plan to address the basketball hoop that's smack dab in the middle of the end wall?

You could take a different approach by putting the screen to one side of the hoop, your pulpit (or just the preacher) to the other side, and your cluster directly under the hoop.

[ProSoundWeb Community]