PA Speaker design

[Wheels]

Well, I got the figures ran quicker than I thought I would and now I need a speaker design. I would like to keep the total speaker cost (excluding monitors and amps) around $2,000, but if it can't happen for that much I can delay a few other purchases to free up a few extra dollars.

I found the Eminence Delta Pro-12A with the Eminence APT-50 Super Tweeter and a Eminence H290 horn. I thought they looked promising, but I am open to any recommendations. I know I'll need a sub or two, but I don't really know where to start there. Cabinet design, which is better: two main cabinets with several speakers, or several cabinets?

I would like 1,200 watts power handling, but I guess the real importance is mid to upper 120's for max spl. 8 or 4 ohm, whichever works best. I would prefer 8 ohm for future expansion.

its an 80ft x 60ft church auditorium for any of you who are curious

I plan on powering them with the Behringer EP2500 bridged mono.

Thank you in advance
Wheels

[John_E_Janowitz]

Hi Wheels,

The first thing we should do is figure out what you're actually going to need to fill that space nicely. I've done a lot of these type of installations, and often times the biggest challenges happen because of poor room acoustics. Reflections off the side and rear walls can be huge issues to deal with. Getting the right placement and coverage pattern for the room is also a huge issue. In most cases matching the system to the room is even more critical than building a good speaker. Is it possible to take some pics of the room and post them or draw out the layout? Or you could email them to me as well or in a private message if you don't want to post them for everyone. Also, it sounds like you may have posted elsewhere with more info on the system. What kind of music does the church do? What instruments are being mic'd? That will also tell you what other things you need.

As far as the drivers go, I don't think the Deltapro 12A and APT50 are going to be an overly good option for you. The 12" woofer is going to have a very difficult time playing up high enough to match with that compression driver on that horn. That said, you might want to check out my reply in the following thread here. http://www.htguide.com/forum/showthread.php4?t=32036

Again I would highly suggest for most any case to do an active system for live sound. The DCX2496 is cheap and will save you a lot of money in the long run. You can do crossover, EQ for your speakers, separate EQ for the room, time delay, compression, limiting, etc all from one unit. A second Behringer EP2500 or EP1500 for highs is not too expensive.

We may be offering xover plans for a 2way with TD12M and some 1" compression driver we haven't fully decided upon yet, but I currently have settings on the DCX2496 that you could dump right in. Now, depending on the room though, a 2way with a horn is not always the best option. I've done lots of line arrays with inexpensive drivers that can work extremely well. The following array here was done with the Silver Flute 6.5" drivers and Silver Flute YAG20 ribbons.



These are in a church that is more of a square with the altar in one corner, about a 60x60ft room. With the 6 individual boxes you can do several things. First you can aim them properly so that the top box is aiming about head height at the back of the room. When hung up high, that means that the sound is hitting head high in the back, hitting the wall and bouncing downward where it dies out. You don't have to worry about the reflections coming back forward nearly as much. Secondly you can aim say 3 of the top boxes together towards the back of the room. They will sum more and project more sound to the back. This allows you to control the volume so it is very even and nearly the same as you walk from the back to the front of the room. You can see that in the following picture at the Five Six club.



For concerts the arrays move forward about 15ft to the front of the stage. The top 3 boxes are then aimed together towards the back of the room, head height. The next 2 boxes are aimed together towards the middle of the room and the bottom one box is aimed by itself more downward to cover head height when sitting at the first row of tables in front of the stage. Walking from the back to the front of the room gives no real variation in the sound levels.

The small array also gives you very good horizontal dispersion and quite good power handling. An array of 6 of the 6.5" drivers easily gives you levels into mid 120's all the way to where you'd need to cross to a subwoofer. Something like the TD15H or X then would cover you down to 25-30hz range in the mid 120's as well. This is what I built and donated to my church recently. Our room is probably similar volume but is somewhat of a 1/4 pie shape with the stage in the corner. Also, one thing you should work into the budget is definitely some room treatment. You can do this quite inexpensively by making sound panels yourself. A 2x4 frame with the heavy insulation wrapped in cloth or even in a cheap sheet from walmart can work extremely well.

Anyway, hope that gives you some things to go on. I'll be glad to help you figure some things out if you can get a little more info on the room.

John

[Wheels]

John, thank you for the willingness to help. Just to let you know, I am not qualified to do this, I was just willing to tackle it.

Here is the pics of the auditorium, the ceiling is 20ft and it is just the roof of the steel building. I had been planning on setting the speakers on shelves about 10' above the floor and the subs below them on the floor, but if they should be hung I can do that too. Let me know if you want any other information on the room. We have just dug the footings, so some modifications can be made.

I like the sound deadening idea. I didn't realize that would work. We do Contemporary music (Mercy Me, Chris Tomlin...). Instruments are 2-4 guitars (half acoustic), 1 bass, keyboard (future) drum set (enclosed). Everything will be miked.

well, I'm having difficulty with the pics. I'll post them separate

[Wheels]

Here are the pics

[John_E_Janowitz]

Hi Wheels,

Looking at the view on the right, are those black rectangles the proposed speaker location? I think those small arrays could be a good choice for your room to get very good coverage both side to side and front to back. I'd put them up close to the ceiling to both sides of the stage. I'd say have them toed in slightly and aimed to the center in the back of the room. Any sound panels or diffusers you can make for the side walls would probably help out quite a bit probably in the back 2/3 of the room.

With regular pricing on the W17RC8-08 and the YAG20 ribbon from Madisound you'd be looking at $1110.40 for the drivers. I'd expect there is a quantity pricing you get at 16pcs of each total. I'd go with 8 per side if possible with the array in a J shape. The top 3 boxes aimed head height to the back, then 2 sets of two and finally the last box aiming head height in the front. That should allow for very even coverage throughout the room. You can use the Ease Focus software and just pick an array that has 6" drivers to get a very good approximation in the room. http://easefocus.com/

With 8 per side you're capable of 127dB down to low 70's with 640W total to the array and still within excursion limits nicely. From there you can cross to a pair of subs. The TD15X's like I did in our church could do quite well. Obviously I'm biased to them as I make the drivers. A pair of these subs would get you into the mid 120's all the way to about 30hz or so. Plenty low enough for any real instruments. They could likely go off in the corners, or be mounted right above the arrays.

I have plans I can give you for the sub enclosures. I also have plans for the small array boxes. I like to make the individual boxes, then array them and connect them together. That small array just have 18mm baltic birch panels on the sides to hold them all together. You could connect them with angle iron, etc as well. I extended the side panels by about 2" above and below the array. Then sink 1/4" thick x 2" wide steel flat bar into the panels. That gives you the strength needed to meet the safety margins for hanging them.

Again I'd suggest going with something like the DCX2496 for processing. You likely don't really need stereo for live sound, although it may be nice to have it. You could probably end up with using one channel of an amp for all the 6.5" and one channel for all the tweeters. Two amps with 4 channels total would allow you to do stereo though. You'd need one other amp then for the subs. Figure if you bought the Behringer EP2500's you'll spend under $300 each. Either a $600 or $900 investment in amps. The DCX2496 is also about $300. You can run out of the mix board into the DCX2496 and out to the amps.

The small 2ways we have with the TD12M and the XT1086 horn could also work to get plenty of SPL in there. Building a single 2way cabinet per side will be much less work. IF you're really looking to get even coverage in the room and have more ability to control the reflections, the array woudl be the way to go though.

John

[cjd]

Just want to say: John, you're a classy guy. Clearly most of us are out of our element with PA stuff.

[Wheels]

Wow. Thanks from me and my church. may God bless your business abundantly. I would definitly be interested in those plans if you would send them to me. email, PM, or whatever... I would pay for shipping if you need to mail them. Also, what would be the pricing on your sub? Could I set them on the floor directly below the arrays? There is talk of using this as a gym occasionally through the week. How would a metal grill material mounted 1-2" in front of the speakers effect the sound?

That was a speaker location we were thinking about in case we didn't hang the speakers.

I like the processing ideas. I'm most likely going to go with 1 EP2500 for the arrays so I could upgrade in the future and save money now. I plan on using another EP2500 to power the subs unless you have a better recommendation.

How should I hang the arrays? I figured on using angle iron for the sides and a chain each on the top corners along with a chain each on the bottom corners to tweak the angle.

Those drivers on the 10+ price came to $999.36 BTW

Thanks again. Hope you had a Merry Christmas.
Wheels

[ThomasW]

You'll need an active crossover and a second power amp to do what John suggested.

[Wheels]

Oops. your right again Thomas. I will need a second amp. The DCX2496 is the active crossover I am going to use, I just forgot to mention that in my post.

Thank you,
Wheels

[John_E_Janowitz]

Hi Thomas,

If he wants to run the system just in mono he can get away with the single amp for now. Just running the mids on both sides in parallel off one channel and the tweeters on each side in parallel off the other channel. As long as placement in the room and the room itself is symmetrical, you can get away with this. No different than a cluster of 3 in the middle aimed in an arc.

John

[Wheels]

I forgot that amp was rated for 2 ohm in 2 channel. Mono works for now, but it would be nice to have separate left and right channels down the road.


John,
If you want to just send me a list of dimensions for the box and port, we can build them from there. I come from a family of trim carpenters, we have had a lot worse to build off of.

Thanks
Wheels

[John_E_Janowitz]

I haven't forgotten about this. just been very busy. send me an email to sales at aespeakers.com and I can get you some info.

John