Audio - Live Sound - question

[Dennis Peacock]

I'm researching PA speakers for our church. There seems to be tension in the market between self-powered speakers (like the QSC K12's) and passive speakers. I've been told that passive is the way to go for longevity purposes but I don't want to get in the business of keeping up power amps, very long run cables, and etc.

Does anyone here have any experience or professional advice for someone looking to put good quality speakers and a sub in a room that is: 50 x 50 with 20 ft ceilings.??

Do the self-powered speakers go bad faster because the amp goes out? I'm not talking the bottom end of powered speakers because the QSC K12's are $800 each. Small church with less than 100 people and a very small budget to work with. I just want to make as good a decision as I can without wasting money, time, or effort.

Tips, advice, experiences, wisdom all accepted.

[Allan Speers]

All things being equal (and they never are) active speakers are far, FAR superior in every way. The amp & crossover can be perfectly matched to the drivers. They can implement brickwall protection, they can correct for phase and timing issues.

Whomever said passive systems last longer was selling you oceanfront property in Arizona.


Having said that, the number of different TYPES of systems, and the number of opinions on how to best treat & cover a room, will make you insane very quickly.

Here's the best advice I can give you: Take your total budget, then triple it. After that, allocate at least 2/3 of that amount to treating / modifying the room, stage, cue system, etc. If you have a band, get electronic drums. Spend the remaining 1/3 on the actual sound system. I know this won't actually happen, but it's the best advice you will ever get on the subject.

Fly the subs, don't put them on the floor. Use 10" or 12" drivers for the vocals, not 15's. The QSC K series is about as good as it gets for the money (also ART) but is FAAARRR from what any pro would consider top-end quality. They also don't array well, though if you have no balcony, a 50 X 50 room probably doesn't NEED an array. Still nice to have, though. Better coverage, less feedback, lower distortion .... But it sounds like you can't afford real top-end stuff, and probably will be just fine without it. So yeah, QSC is good.

Get really good compressors, but don't overuse them or you'll feedback like crazy.
If you need lavalier mics & wireless transmitters, buy the absolute best you can afford, as these are typical weak links.

You didn't give nearly enough info for any further recommendations.

FWIW, I'm a life-long recording engineer and FOH soundman.

[Dennis Peacock]

Thank you Allan!!!
I will be rewiring the current sound system as most all the xlr connections at the stage no longer work as someone a long time ago put surface mount connection on the stage and every person and kid that has walked or ran on that stage and kicked and broken almost every locking latch on almost every xlr connection. We now have floor boxes that I will install, put in new xlr jacks, move the floor monitor connections inside those boxes and almost move a/c power connections below the surface of the stage. I am having to teach myself about church audio and just trying to figure out who has the best info so I can make a better informed decision is an overwhelmingly daunting task to say the least!!!
The current setup is a Mackie ProFX22 analog board, an old 800 watt amp that has been fixed and kicked more times that they can count, an equalizer that is in the rack but not hooked up to anything, the mics are made by "Blue" a dedicated set for vocals and a different type of "Blue mic set for instrumentation. I bought these to replace the $25 mics they had been using as most of them had broken and only 2 mics left were working. I talked to Sweetwater Music and they sold me on some Blue enCORE100 and enCORE100i mics which are miles better than what was currently in use.

The current speakers are a pair of PA speakers that are center ceiling mounted. That's all. No more speakers. My idea is to take those down, install the QSC K12's in the corner, up high, on each side of the stage. I was looking at a sub as well but didn't know that I needed to "fly" the sub. Many places I've seen have the sub under the stage with sound screens between the steps to allow the sound out from under the stage. I can't do this. It has taken us a year to get what we have now and I have to learn how to install all this stuff because we can't afford to hire it done.

The old amp has been giving me troubles and I simply don't know about hooking up the EQ for the entire house sound. I simply don't know how I should hook it up....or if I even need to hook it up.

In short, I'm working to simply improve what we already have in both design and quality. Feel free to email me at woodspinner at sbcglobal dot net if you'd be willing to talk me through some of this offline.

Thanks again for all your advice as it is GREATLY appreciated!

[Ken Fitzgerald]

Dennis, check with some local music stores. I have a friend here locally who has been a professional musician since he was a teen. He owns a music store and sells PA systems. The band he's played in for over 30 years has a PA system and a spectrum analyzer. They go into a new building/room for a gig. He uses the spectrum analyzer to analyze the acoustics of the room and he adjusts his PA system accordingly. He sells PA systems too. Check around locally. There may be some professionals who can guide you.

[Dennis Peacock]

Thank you Ken! I'll research that now.

[Allan Speers]

Dennis, check with some local music stores. I have a friend here locally who has been a professional musician since he was a teen. He owns a music store and sells PA systems. The band he's played in for over 30 years has a PA system and a spectrum analyzer. They go into a new building/room for a gig. He uses the spectrum analyzer to analyze the acoustics of the room and he adjusts his PA system accordingly. He sells PA systems too. Check around locally. There may be some professionals who can guide you.

Hey ken.

These days, that's actually a bad way to do things, unless he has a realtime analyzer/EQ, and those are incredibly expensive & tricky to use properly. Even then, they are a serious trade-off, used only for non-permanent venue situations. No offense to your friend, he's just following an old model. Again, in a situation where you can't alter the room and will only be there for one night, sometimes it can be considered a worthwhile trade-off, but not by most people, these days. Most companies don't even do that any longer with touring systems, nor major event installs. The problem with that idea is threefold:

1: The response will be different, sometimes VASTLY different, in various parts of the room. (That's why at least 2/3 of the budget SHOULD go to, and in high-end situations DOES go to, fixing / modifying the room itself.)

2: The response of the room changes drastically once it's full of people.

3: Using a graphic or parametric EQ will always make things sounds worse, even though it may make the worst areas of the room sound a little better. Also, the frequencies that ring will still rings, just at lower volume. ### When there are problems in a room, it is not specifically because "some frequencies are louder than others" but because some frequenceis (nodes, odes, whatever) are ringing longer than others. The result is uneven volume, but the cause is difference and must be understood. An EQ does NOT change this, it just puts a bandaid on the symptom. Plus, again, when you make the worst part of the room sound better, you almost always are making the best part of the room sound worse.



In a permanent situation like Dennis has, even if they don't have the budget for major room alterations, one can still take the time to experiment with speaker placement, crossover point, and a few other things, which will all go a long way towards providing "even" coverage and minimal feedback.

- But this is a very complicated subject.
Dennis, I once again stress STRONGLY that you guys try to find someone locally who understands architectural acoustics, not just PA systems, and do at least SOME tweaking of the room. At a minimum, get some full range absorbtion happening, reduce reflections into the congregation and get rid of multiple nodes. A 50 X 50 room is already a problem, as the two equal dimensions create equal nodes that will take off on you.

Find someone who understands that last statement, and you should be good to go. Again, I can't offer more advice as I have no idea what your total situation is. A small, intimate Catholic thing with just talking, or a huge born-again revival with an on-stage choir and full band? Big difference!

Anyway, the most important thing you can do is to find the right person to trust. Chances are very good he won't be working at the local "music store." Look for a company that specializes in event / industrial installations. As with power tools, you'll pay more, but you'll only pay more ONCE.

[Jim Becker]

Dennis, I have some experience with this. You know how to get in touch with me. And I absolutely agree with Allan that a qualified local resource is worth whatever it takes to get. The room itself is a "critical component" that has to be taken into consideration and that's not something any of us can truly help with from a distance. And things are "more interesting" given that you're not just needing to accomodate voice ... the instrumentation comes into play, too. There are firms that specialize in sound reinforcement and yea, they're not usually associated with the local music store!

[Ole Anderson]

You have some good advice here, but even pros don't agree as to which is best, really a case by case answer.

Join the FB group: https://www.facebook.com/groups/ChurchSoundMediaTechs/ 12,000 plus folks that deal with this day to day. Lots of opinions. We average 120 folks (traditional) and used passive 8" EAW speakers with Crown digital signal processing amps for choir monitors, floor monitors and FOH (stereo, a pair up front and a pair further back with delay). One 15" floor mounted EAW sub, but again we are traditional but I have pushed 95 dBA. I don't want to get out a scaffold if something goes wrong with the amp (we have four). Our system was recommended and provided by a local integrator that specialized in church sound systems. If something goes wrong, you have someone to call. I did most of the install. They returned and tuned the system to our space. We didn't need any room treatments. Our system is 8 years old so we still have an analog board.

[Brian Elfert]

My church was built in 1968 and is a "modern" church. Basically a big square box with no carpet or anything else that absorbs sound. Audio was an issue for many years. Finally, about 20 years ago the church had the ceiling sprayed with some sort of sound absorbing material. The church almost sounded too quiet the first service after this was done, but audio is much better now.

[Allan Speers]

The current setup is a Mackie ProFX22 analog board, an old 800 watt amp that has been fixed and kicked more times that they can count, an equalizer that is in the rack but not hooked up to anything, the mics are made by "Blue" a dedicated set for vocals and a different type of "Blue mic set for instrumentation. I bought these to replace the $25 mics they had been using as most of them had broken and only 2 mics left were working. I talked to Sweetwater Music and they sold me on some Blue enCORE100 and enCORE100i mics which are miles better than what was currently in use.

The current speakers are a pair of PA speakers that are center ceiling mounted. That's all. No more speakers. My idea is to take those down, install the QSC K12's in the corner, up high, on each side of the stage. I was looking at a sub as well but didn't know that I needed to "fly" the sub. Many places I've seen have the sub under the stage with sound screens between the steps to allow the sound out from under the stage. I can't do this. It has taken us a year to get what we have now and I have to learn how to install all this stuff because we can't afford to hire it done.

Blue makes very good mics, FWIW.

You don't HAVE to fly the subs, it just minimizes other problems, especially when the congregation is very close to the stage. (Time & phase issues, mostly. Folks in the front row will be much closer to the subs than the mains, so it will sound bass-heavy or muddy.) ) Also, floor-placed subs tend to cause more unwanted sympathetic vibrations than flown subs. You also tend to be more limited in placement, so end up with more nodal problems.

Again, a very complex subject, with lots of different workable solutions, all with trade-offs. You just need to find the right local guy. - But so many people CLAIM to understand this stuff, ad they really don't, so be careful.

One suggestion regarding subs: Get two smaller ones, not one large one, and do NOT mount them close enough for the coupling effect. Here's why I say this: With two, you will get some phase smear, but you will also get a more even response throughout the room, because they will be exciting different nodes. With just one, or two of them coupled, you will get a tighter, punchier bass in the center area, but things will most likely be way off in other areas. better to have a slightly soft bass everywhere, than way too much for some members of the audience. There are software programs, and even just basic analog techniques, for minimizing these issues, but again you need someone that REALLY knows what they are doing.

[Allan Speers]

My church was built in 1968 and is a "modern" church. Basically a big square box with no carpet or anything else that absorbs sound. Audio was an issue for many years. Finally, about 20 years ago the church had the ceiling sprayed with some sort of sound absorbing material. The church almost sounded too quiet the first service after this was done, but audio is much better now.

"The church almost sounded too quiet"

I can tell you exactly why: Because those spray-on solutions are ridiculous. All they do is absorb some of the ultra-high frequencies, while doing nothing for the mids and upper-mids, which is where they main problems usually are.
So, you end up with less intelligibility, yet still mid-range smear, etc. So many companies do that nonsense, because it's easy & relatively inexpensive.

Another related issue, which you just touched upon, is that you do NOT want a dead room. We are not building a recording studio control room here. You want maybe 0.6 - 0.7 seconds rt60 (reverb decay time) so the room sounds alive, but you want that decay as even as possible across all frequencies, and at as many areas of the room as possible.
Plus, you want as little extra reflections, inside the Haas limit, as possible, also in all areas.

Again, you need to find someone who understands that last statement. Otherwise you're just throwing money down the toilet.

[Ken Fitzgerald]

Allan...you need to hear with a cochlear implant to appreciate reflected sounds. It seems the mechanical inefficiency of the 3 bones of the middle ear reduces the ability of the normal hearing person to hear those reflected sounds. When you hear with a CI, the sound is converted to electrical stimulation and sent to the nerve within the cochlea bypassing the middle ear. The acoustics of the room I am in has a dramatic effect on the whether or not I can understand a person's conversation. I may hear them but not be able to understand what they are saying because of those reflected sounds.

I struggle in our recently remodeled kitchen and dining room as the all the surfaces are hard.

Talking with the same person, I can go into our carpeted living room and understand them well.

[Allan Speers]

Ken, that is REALLY interesting! Sorry to "hear" about this, but also very glad to know about this.

[Brian Elfert]

"The church almost sounded too quiet"

I can tell you exactly why: Because those spray-on solutions are ridiculous. All they do is absorb some of the ultra-high frequencies, while doing nothing for the mids and upper-mids, which is where they main problems usually are.
So, you end up with less intelligibility, yet still mid-range smear, etc. So many companies do that nonsense, because it's easy & relatively inexpensive.

The combination of the ceiling coating and new speakers pretty much fixed the audio problems in the church. I can't tell you if coating the ceiling fixed it, or simply better speakers.

[Allan Speers]

The combination of the ceiling coating and new speakers pretty much fixed the audio problems in the church. I can't tell you if coating the ceiling fixed it, or simply better speakers.

It wasn't the coating, I assure you. Also, give me a small budget and 1 week and I'd make it sound so much better than it does now, you wouldn't believe it. Sit 2/3rds of the way back at Carnegie Hall. That's close to the brass ring. They didn't just spray some foam on the ceiling, believe me.

Of course, no one NEEDS it to sound that good. It's just nice if you can afford it. Berry Gordy recorded all the early Motown hits in a converted house, with mattresses on the walls. Everything is relative.