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Author Topic: Passive speaker suggestions  (Read 3601 times)

Mark Maurer

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Passive speaker suggestions
« on: December 28, 2013, 03:17:08 PM »

Good day, everyone.  I am seeking some input on a speaker purchasing decision.  I am a middle school music teacher and I am looking to upgrade our auditorium speakers.  As our school is broke all of the monies will be raised by my choir students selling chocolate Santas and Easter bunnies - so I have to get this right!!! We currently use (4) Mackie SRM450s on stands (2 per side) in the corners of our 73 wide auditorium.  Since the room has tremendous acoustics they can carry the room with no problem.  (Only the front center is null because of the forced speaker placement.) 

With the goal of relegating the Mackies to the portable sound applications where they belong I am looking to install new passive ceiling mount speakers.  As we have an Allen and Heath ML3000 that runs left-center-right I am looking to utilize three hangs of speakers.  (Our numerous theatrical productions are the motivation behind the center hang.)  Since our ceiling at its highest point is only 22 and then tapers downward to  15  at the rear of the facility I am looking (I believe) for trapezoids as opposed to line arrays.  The remaining room dimensions:  There is 56 of depth from front of stage to the back of the auditorium whereupon the room slants drastically upward with stadium seating that doubles as a classroom.

I had originally wanted 3 hangs of two QSC K12s left-center-right.  During a rental they sounded great playing everything from classical to dance music; since I never had to push them they never got harsh.  However, while the price was still within the high point of our budget the speakers have differing angles on either side (which I believe would make hanging a pair side-by-side more difficult).  Moving on, I have heard that passive RCFs offer great value for the dollar.  Whether I need 6 speakers or just 3 with wide dispersion they - and the amplifier(s) - need to come in under $5,000 preferably.  Any local sound installation companies that check out our room try to sell me their representative brands.  Help!  I need unbiased advice.  On behalf of my students and me, thanks.
-Mark Maurer
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g'bye, Dick Rees

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Re: Passive speaker suggestions
« Reply #1 on: December 28, 2013, 03:58:35 PM »

Mark...

Welcome to the PSW Forums.

It would be helpful if you would care to post your location so that local help becomes an option.  Since you want to hang the speakers, you'll want to do it properly and have them placed in the proper places and orientation by someone who is licensed, bonded and insured for such work.  This will keep your insurance company happy.

Otherwise it sounds like you're pretty much on the right track as far as coverage goes.  I'm sure others will have more questions and advice.  I'll begin and end with the "hire qualified help" caveat.

Best of luck.
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Tom Young

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Re: Passive speaker suggestions
« Reply #2 on: December 28, 2013, 04:16:24 PM »

That is a very well presented outline of what you are looking for, why and what some of the conditions are, including your low budget. Thanks for that.

Multichannel loudspeaker systems (stereo and/or LCR) when done "by the book" are governed by one primary rule: each cluster must cover all of the audience/seating. If this is achieved, everyone can better hear each signal/source regardless of how they are panned. The reality is that very few multichannel systems are done "right". In practice, we work our way around this simply by not hard-panning any source (all the way right or left) other than (perhaps) stereo signals such as that provided by an electronic keyboard, overheads on a drum kit and multi-microphone choir. But even with these, panning part way left or right is probably the better approach.

Bear in mind that stereophonic sound reinforcement "works" only for those seated in or near the center. Those off to the sides do not hear an accurate representation of where the signals are panned to for localization. This is the case for home playback systems as well as large scale concerts and theatrical productions.

IMO multichannel reinforcement is useful/justified for achieving a spacial (2D) sound field but hardly ever for realistic localization. One exception is a VERY well designed professional production as found occasionally on Broadway and Bus&Tuck tours of some Broadway shows. In these shows there are likely to be concealed ldspkrs in scenery, etc. as well as a very carefully designed multichannel ldspkr system.

But when you think about coverage from each cluster in a stereo or LCR system it is apparent that the left and right clusters, if spread very wide, need (as little as) somewhere around 90-degrees horizontal coverage. The center cluster needs 180-degrees. Period.

So you may need only 1 90-degree ldspkr for the left and right hangs and 2 90-degree ldspkrs for the center. Note that we have not looked at and addressed vertical coverage.

Do not let the cabinet shape (and specifically asymmetry) deter you. We hang ldspkrs (relative to one another) how they need to be hung for coverage.....not by how they fit (space or shape-wise) one another.

You are right. This is not a space for line arrays. "Point-source" is the tag given to non-line array loudspeakers which are designed to be used by themselves or in clusters. When more than 1 ldspkr is required we array them to increase the coverage but (also) not overlap onto each other's coverage area. We also strive to not project sound where it is not needed.

I can't comment on the RCF stuff. But Electrovoice makes a very impressive line including the Zx5 (15" 2-way) and Zx4 (12" 2-way) which perform very well and are reasonably priced. These (like others) are light-weight, well-designed and have rigging kits (bought separately).

As Dick points out; you need a pro when suspending anything above peoples' heads. No arm-chair riggers.

That's it for a start.
« Last Edit: December 28, 2013, 08:49:51 PM by Tom Young »
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Tom Young
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Brad Weber

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Re: Passive speaker suggestions
« Reply #3 on: December 29, 2013, 09:47:30 AM »

Since your budget is tight, don't forget to consider all the costs you may encounter.  For example:
 
  • Speaker cable and any costs associated with getting it to the new speaker locations.
  • Addressing the additional center channel in terms of cable, processing and so on.
  • If you may need to supplement your existing power in order to add any additional amplifiers.
  • Any substructure and hardware needed to fly the speakers and properly attach them to the existing structure.
  • Connectors, solder, soldering iron, cable labels, rack screws, zip ties and all the other little items that are required for a proper install.
  • Properly qualified and insured professionals to perform any actual flying or rigging.
With all of these ancillary costs accounted for you may find that a fixed budget does not leave as much as you thought for the speakers and amplifiers themselves.

Added: As Tom said, this is not trying to be negative but rather pointing out that there can be costs involved with installing a speaker system that may not be obvious to those familiar with that type of work.  I would prefer to avoid you spending all of your budget on the major pieces of gear only to then come to realize that implementing it also has costs.  It would not be the first time new equipment sat in storage unused for some time until the user was able to obtain funds to properly install it and I'd guess you'd want to avoid that.
« Last Edit: December 30, 2013, 12:11:39 PM by Brad Weber »
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Tom Young

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Re: Passive speaker suggestions
« Reply #4 on: December 29, 2013, 02:29:31 PM »

Not to load up on you and possibly dampen your spirits, but........

You will also need DSP with enough inputs and outputs for this system, plus perhaps future additions.

Now:
(3) inputs, 3 outputs

Future additions:
1 out - for subwoofer OR: 1 in, 1 out - for aux driven subwoofer
and:
1 in, 1 out - for front fills (if needed)

You need DSP so that (at some point in time) you can have the system measured and optimized by a specialist with the necessary training and measurement system. DSP will provide high-pass filters, crossovers for subs, delay, parametric equalization and system protection (limiting).
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Tom Young
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Mark Maurer

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Re: Passive speaker suggestions
« Reply #5 on: January 11, 2014, 03:07:27 AM »

Not to load up on you and possibly dampen your spirits, but........

You will also need DSP with enough inputs and outputs for this system, plus perhaps future additions.

Now:
(3) inputs, 3 outputs

Future additions:
1 out - for subwoofer OR: 1 in, 1 out - for aux driven subwoofer
and:
1 in, 1 out - for front fills (if needed)

You need DSP so that (at some point in time) you can have the system measured and optimized by a specialist with the necessary training and measurement system. DSP will provide high-pass filters, crossovers for subs, delay, parametric equalization and system protection (limiting).

I really appreciate all of the advice and the time that you folks took to respond.  It is so appreciated!  I want to try to answer all of points that were raised.

First off our middle school is located 20 minutes south of Pittsburgh, Pennsylvania.

Another common theme in all of your replies was the wise admonition to find qualified help for the install.  To that end, here was my plan:  I have friends in the professional lighting business; they have gone above and beyond to help out our middle school lighting needs the last few years.  Additionally, they do large lighting installs all the time - many of which involve hanging large and heavy light bars with special weight approved steel cables and hardware that they have to special order.   I was planning to use their talents and materials to do the speaker hangs.  (Plus they are licensed and insured.)

Another friend spent many years as part of the stage hands union in Pittsburgh.  He offered to assist them if they need it.  Further, I can do a fairly decent job of EQ-ing a room.  Between all of us I feel confident that the install will go as it should.  Are there any red flags that stand out to anyone?

Lastly, we already own a DSP unit:  It is the Peavey VSX 48  (4 in / 8 out).  While the unit is definitely on the low end of the price spectrum it has performed quite well for us thus far.  In this new install the four ins would be LCR and sub, while the outs would run Main LCR, sub, and a future LR rear fill for the stadium seating in the rear of our auditorium.

Thank you for the suggestion of the Electrovoice Zx5 and Zx4 speakers.  I am definitely going to try to find them to give em a listen.  Any other speaker suggestions? 

Thank you all!

-Mark Maurer
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Chris Eddison

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Re: Passive speaker suggestions
« Reply #6 on: January 11, 2014, 09:54:31 AM »

Lots of High Schools on this side of the water are installing Tannoy cabinets at the minute. The V12's seem particularly popular. I own 4 V12's myself and have always been very pleased with the sound. They've got a 90 degree dispersion pattern which will help you with Tom Young's suggestion of making sure each speaker is heard by everyone. They're also easily connected together in to a cluster as the cabinet angles (for wedge purposes) are set to allow easy bolting together side by side with the angle pre set to cluster in the best possible way. The yoke mount is especially useful in situations like yours where the cabinet is being flown.
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duane massey

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Re: Passive speaker suggestions
« Reply #7 on: January 12, 2014, 10:08:09 AM »

You won't get perfection (or even come close) on a $5k budget, but you certainly can make a big improvement over your current rig. Just putting up a good center cluster would make a significant difference. If you find your budget doesn't fit the grand scheme, consider simplifying your first step with plans to expand at a future time. Good luck.
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Duane Massey
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ProSoundWeb Community

Re: Passive speaker suggestions
« Reply #7 on: January 12, 2014, 10:08:09 AM »


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