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Author Topic: Choosing main speakers  (Read 4388 times)

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Choosing main speakers
« on: August 31, 2004, 10:34:12 pm »

Hi. This thread is spun off from the "Single 18" Subwoofers" thread. I've decided that the most important thing for now is to replace the main speakers, not the subwoofers. I am a member of a large Christian organization on the Purdue University campus. We are looking for a way to upgrade our PA system that will get us the greatest improvement in overall experience for our audience. We have two acoustic guitars, 1 electric guitar, a drum set, an electric bass, a keyboard, and three vocal mics at any particular event, and vocal intelligibility without fatiguing is very important to us. We currently have two older Peavey dual-15" bandpass subwoofers, loaded with Black Widow woofers, to handle the bass. The room is a large lecture hall, with balcony seating, and a total capacity of over 400.

What main speakers should I consider? I heard once that for midrange clarity, 12" woofers were preferable to 15" woofers. Suddenly, though, I seem to be hearing that I should be considering tops that use 15" woofers instead of those that use 12's. So I want to know, what top boxes should we be considering with a budget of $1200, or $600/side. There will be a single top box on each side of the room, pole-mounted. Also, why wouldn't a 12"+HF box be suitable for this application?

I spun this thread off from the single-18" subwoofers thread, because we are no longer looking for subwoofers, but mains.
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bo putnam

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Re: Choosing main speakers
« Reply #1 on: August 31, 2004, 10:43:13 pm »

Hey...

Great idea to spin-off.

Can you tell us what brand active crossover you are employing, and where (slopes, too)?  That might help in suggesting "mains"...  Again, 12's or 15's really doesn't matter, per se. It's what you expect them to do.  If you're stuck at 250Hz then some 12's might be fine.  

I'd still suggest a lower crossover point, thereby reducing the output of the subs, hopefully throwing more sound out from the mains, rather than suffering with difficult-to-control acoustic coupling between the subs and the building.  

Also, give us some physical aspects and dimensions: room depth, width and height, as well, are the walls largely windows, some curtains, carpeted, etc.  Any info is critical.  
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Dave Rickard

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Re: Choosing main speakers
« Reply #2 on: September 01, 2004, 12:43:33 am »

I would not agree that 15's and 12's are both the same.  From your background in DIY, you know that beaming and cone breakup modes occur at the usual crossover point of a 15" two way system.  Also the crossover point can be higher on a 12, so the horn does not distort when pushed at low frequencies, and the resonance peak is more easily hidden (unless it's ferro fluid cooled).

In my opinion, it takes a better designed 15" 2-way to sound as good as a 12" 2-way in the range you intend to use it.  12's are more portable too.  Others may correct me if I'm in error.

my $.02,
daver
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Dave
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"If you don't have good stuff at each end of the signal chain, (mics and speakers) what you use in between is just turd polish."--Dave Dermont

bo putnam

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Re: Choosing main speakers
« Reply #3 on: September 01, 2004, 10:19:49 am »

daver wrote on Tue, 31 August 2004 21:43

I would not agree that 15's and 12's are both the same.  From your background in DIY, you know that beaming and cone breakup modes occur at the usual crossover point of a 15" two way system.  Also the crossover point can be higher on a 12, so the horn does not distort when pushed at low frequencies, and the resonance peak is more easily hidden (unless it's ferro fluid cooled).

In my opinion, it takes a better designed 15" 2-way to sound as good as a 12" 2-way in the range you intend to use it.  12's are more portable too.  Others may correct me if I'm in error.

Well, I'm not "Others" but I'd like another kick at the can...

I said either might be a good choice depending on what they are expected to do.  The noise about "beaming" at "usual crossover points" is confusing.  And, no horn should be pushed "low" - that is simply wrong application.  I don't get the impression portability is an issue...

Budget, is, and that might preclude some othewise great choices.  If you're lovey-dovey with a 12-in 2-way (12/2) you could consider the EV QRx 112/75.  A great cabinet, with a 3-in voice coil on the CD, and importantly, a 75-degree dispersion (horizontal) constant-directivity horn.  If you can see clear for a 15/2, the 115/75 is a better choice for your application, IMO, which also has the 3-in CD.  To refute the crossover noise (above), both these have internal passive xovers at 1,800Hz (and could be bi-amped if you choose).  Frequency response (-3dB) is 75-15kHz and 60-15kHz, respectively (the 15 reaching slightly lower).  The 115/75 has slightly higher power handling; both have EV's remarkable RMD cabinet design, and need almost no EQ right out of the box.  The 3-in CD is very, very smooth; overall voicing excellent and soundstage very clean.  Both have integrated pole mounts in their base, and can be flown.

http://www.electrovoice.com/Electrovoice/products.nsf/allpag es/066D59279DD6D93886256B96005D4B0A
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bo putnam

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Re: Choosing main speakers
« Reply #4 on: September 01, 2004, 10:29:51 am »

As well, EAW has some qualified nominees, for sure.  Both the FR129z and FR159z (12/2 and 15/2 respectively) should be considered, and the JFX290 and JFX590 (each with 90-degree horizontal) as well.  

http://www.eaw.com/products/FR/

I've use all these I suggest here.  I have found the larger-diameter voice coils on the CD of the EV QRx's to be much smoother / less harsh, and offer greater resolution before break-up at high SPL's.  
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Don Boomer

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Re: Choosing main speakers
« Reply #5 on: September 01, 2004, 10:56:16 am »

BHFProfessional wrote on Tue, 31 August 2004 19:34

 The room is a large lecture hall, with balcony seating, and a total capacity of over 400.
So I want to know, what top boxes should we be considering with a budget of $1200, or $600/side.

I spun this thread off from the single-18" subwoofers thread, because we are no longer looking for subwoofers, but mains.


Sorry, your budget is just un-realistic.

$600 might be loud enough but I don't think you stand a chance of any clarity given your situation.  You are gonna need some serious HF drivers and horns and they just don't come at that price (new).  You'll probably need speakers to aim into the balcony too.

Your Peavey Subs aren't a problem at all compared to your need for tops!

As to whether to pick 12s or 15s? It's all a matter of what horns and drivers are married to them.

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Dave Rickard

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Re: Choosing main speakers
« Reply #6 on: September 01, 2004, 12:17:31 pm »

Chinacat wrote on Wed, 01 September 2004 15:19

  The noise about "beaming" at "usual crossover points" is confusing.  And, no horn should be pushed "low" - that is simply wrong application.  I don't get the impression portability is an issue...

Budget, is, and that might preclude some othewise great choices.  

 To refute the crossover noise (above), both these have internal passive xovers at 1,800Hz (and could be bi-amped if you choose).


Chinacat,

Welcome to the board.  I hope I'm not offending you.  I'm not trying to start arguments here.

1.  Rory said in an earlier post, "Transportation is a big concern. Right now, we have a pickup bed to work with. I think they need a covered trailer, but we have a very limited budget."  Your impression that portability is not an issue is wrong.  It's a "big concern".

2.  If you don't understand the "noise about beaming and crossover points", you might consider researching to find out if what I say is true.  Your understanding of this is irrelevant to actual driver behaviors.

3.  Your point about pushing a horn too low is correct, and supports what I said about the woofers.  As a woofer reaches it's upper limits it starts misbehaving (beaming, breakup modes).  A "typical" 12 can be (linearly) crossed higher than a "typical" 15.  This means more linear response for the woof and less low frequency load on the horn.  Thus, a "typical" 15" 2-way has to be better designed to match well, especially if it's matched with a 1 inch throat horn/driver.

4.  You posted about being careful about crossing over in the "second decade". I agree

For the record, I'm not lovey-dovey with 12's.  My 2-way mains are all (IMO) well-designed 15's.  But I can't abide with the idea that there's no real difference between the two.

No offense intended,
Dave

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Dave
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"The wrong piece of gear, at the right price, is still the wrong piece of gear."

"If you don't have good stuff at each end of the signal chain, (mics and speakers) what you use in between is just turd polish."--Dave Dermont

bo putnam

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Re: Choosing main speakers
« Reply #7 on: September 01, 2004, 12:26:50 pm »

Hey, Dave...

None, taken.  Thanks.  I too was trying to separate opinion from something that could be measured, is all.  I believe a 12 and 15 can do nearly the same duty, paired with the right CD/horn.  My preference is to go to the 15, if you can, but above all, it is to urge to larger diameter diaphragms on the CD's.  That is very audible.  

There has been some confusion over portability - it did start with the pickup criteria, but now it seems the set-up is more stationary for a specific hall.  Or, maybe they move the gear in-and-out??  Maybe that's it.  There isn't that much difference size-wise, really.  Biggest issue here is objectives versus budget - as often, they are mis-matched.  

Appreciate your comments, and as with all posts here, prompt me to do more learning...  
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Re: Choosing main speakers
« Reply #8 on: September 01, 2004, 11:59:41 pm »

We have to store all the gear ourselves and truck it back and forth. We have a pickup bed to work with. The balcony is only sometimes filled. A band once brought a pair of single-18" subs and a pair of JBL SR4722 tops (Pre SR-X), and it sounded fairly good. It sounds like if we go that route, the SR4722X tops would do the trick.
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Dave Rickard

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Re: Choosing main speakers
« Reply #9 on: September 02, 2004, 03:38:24 pm »

I sent two emails to you, but maybe I didn't have the right address (?).  Did you get them?

Dave
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"The wrong piece of gear, at the right price, is still the wrong piece of gear."

"If you don't have good stuff at each end of the signal chain, (mics and speakers) what you use in between is just turd polish."--Dave Dermont

Mac Kerr

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Re: Choosing main speakers
« Reply #10 on: September 02, 2004, 03:59:22 pm »

daver wrote on Thu, 02 September 2004 15:38

I sent two emails to you, but maybe I didn't have the right address (?).  Did you get them?

Dave
I know I didn't get them.  Laughing

Mac

ps. Who were you talking to?
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bo putnam

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Re: Choosing main speakers
« Reply #11 on: September 02, 2004, 04:15:52 pm »

Mac Kerr wrote on Thu, 02 September 2004 12:59

I know I didn't get them.  Laughing

Me, neither...  Rolling Eyes
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rubbermatch

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Re: Choosing main speakers
« Reply #12 on: September 02, 2004, 04:53:41 pm »

EV 300SX, cheap($600new), 12/2, loud. You are trying to move too much air with too little money, get them used and use 2 boxes a side. Peavy subs? trade them in for something less boxy sounding like EAW LA400,s 12" horn x 136db, plenty o low end and tight and musical. use a digital processor, if you can get some used EAW kf300i's get them instead cuz you can stickem right next to each other.
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Dave Rickard

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Re: Choosing main speakers
« Reply #13 on: September 02, 2004, 05:25:38 pm »

Oops.  

I was sending them to Rory, a.k.a. BHFProfessional.

daver
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Dave
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"The wrong piece of gear, at the right price, is still the wrong piece of gear."

"If you don't have good stuff at each end of the signal chain, (mics and speakers) what you use in between is just turd polish."--Dave Dermont
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