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Highschool Gymnasium Soundsystem
Old 14th March 2017
  #31
Gear Head
 

Quote:
Originally Posted by de003 View Post
what cable are you buying?

I guarantee you are not getting 2.5mm 4-core for that price, which is what I would expect to see in a PA system install.
Actually, you don't just arbitrarily pick the number of strands, conductors and size of cable for installs, or any other application for that matter. I do purchase 14/4 Belden, ICE and WestPenn high quality, plenum-rated, cable for less than $.45 per foot. This is the same, defect-standard, cable specified by consultants and installed by contractors around the world. So, there is that....
Old 14th March 2017
  #32
Gear Maniac
 

I was hoping someone would actually start to take a crack at a solution for the OP. Here's something the OP can use.

I think we can pretty well assume the space is reverberant and full of reflective parallel surfaces. If there is a fair budget involved at all, addressing the acoustics of the space is almost certainly the most cost-effective way to realize an improvement. Without looking at improving acoustics, it's unrealistic to expect anything but a very poor result, even if a fortune is spent on loudspeakers and amps.

To address the acoustics, one might begin with a few basic measurements like the RT60 at various frequencies. This will quantify how bad the situation is, and identify the frequencies that most need to be addressed. Keep in mind that reverberation can be characterized by the decay time and the tonal value or which frequencies have the longest decay times

RT60 and Alcons measurements can be taken with very simple equipment, but a more accurate analysis will produce better results. Someone who is capable of more acoustic analysis can go beyond simple measurements and identification of the frequencies that are most important to address. They can create a computer model of the space that can be used to help understand the results from various alternative solutions.

Here's a situation that you want to avoid. I've seen where consultants will come in and leave the client with the impression that according to the consultant, they've got to plaster 70% of their surfaces with absorption panels. The client knows three things: their budget won't afford that, it'll look like hell, and it doesn't sound that bad now with no treatment. Therefore they dismiss the consultant and conclude hiring one was impractical in the first place.

The consultant has to communicate better with the client so the client understands three things: the consultant is willing to find practical solutions within the client's budget, the consultant will take other concerns like aesthetics into consideration, and the consultant is committed to realizing an improvement even if they don't get everything they ask for.

"Dead" rooms with relatively low levels of reverberation work well for highly reinforced music (rock band) and low-Q loudspeakers (with poor pattern control). But they are acoustically opposite of what one might desire in a gymnasium space where the fans enjoy the roar of their own cheers reflected off the gym's floor and walls, and the ref doesn't sound like he's blowing the whistle into a pillow. The live space can be kept live, but there may be some specific problems that are well worth addressing. They might be addressed by changing some shapes, materials, or with surface treatments.

As for the loudspeakers, the key to handling reverberant spaces is pattern control. Hi-Q speaker systems allow the designer/installer to control the "beam" for a high ratio of direct-to-reflected sound that maximizes intelligibility for speech, and provides the clearest result for music.

Typical solutions for Hi-Q are horns and "steerable arrays." I would identify specifically coaxial and multiple-entry horns that maintain good pattern control the lower frequencies and have even off-axis fall-off. The digitally steerable array products are more sophisticated (more complex but not necessarily better) solutions to "aiming" the axis accurately and controlling beamwidth. The popular solutions are from Renkus Heinz and EAW. Although it's not really "steerable" I would include JBL's CBT arrays that are based on Keele's Constant Beamwidth Transducer technology which either physically curve an array into a shaded arc-segment of a sphere or they use shading and electronic delay to virtually curve it. The result for the CBT arrays are the desirable narrow vertical beam and excellent horizontal off-axis coverage. Although they are not steerable and may not control the pattern to as low frequency, unlike Heinz and EAW, they might be within the budget. All these array products are horizontally wide, which means they are not suitable for corners or near side walls. They can work well in the middle of the room away from walls, or in the middle of a long wall. If you need to be in the corners, you need something narrow horizontally, and that typically means horns.

Like digitally steerable arrays, multiple-entry horns are not likely in the budget, but coaxial horns are perhaps the simplest and least expensive solution to Hi-Q needs. Keep in mind that pattern control is the criteria and not just being a coaxial or a column array. If it doesn't control the pattern, it doesn't help.

Placing the speakers and aiming them is critical to getting the most direct-to-reflected ratio. An advantage can be gained by using more speakers, placing them closer to the audience, and aiming them more directly -- but only of they aren't just pumping sound all over the place. Fewer speakers that control directivity better are likely to give a better result. Choosing the number of speakers and their placement is a balancing act that needs to take into consideration the details of the project.

Low frequencies are often the worst offenders in a highly reflective space like we anticipate for this gym. The good news is that speech doesn't require the lowest of them for intelligibility. You can roll-off frequencies below 250Hz for speech (like on the microphone channel). For music, consider rolling off below 150Hz. That will help tremendously when the decay time for those frequencies is something like 8 seconds.

In an earlier post, I mentioned a gym the county here built where they put in an expensive JBL line array. Besides making the array too short to do any good, they added subwoofers to it. Subwoofers in a room that probably has an RT60 like 8 seconds at those frequencies. Just imagine the kind of articulation you can get with a subwoofer in a tunnel. Let's just say this isn't the place for the boomin' system.

With the acoustic issues at low frequencies, and keeping the program material in mind, which was described as speech and playback of recorded music, rolling off low frequencies can be an effective solution. I assume we're talking about background music, something motivational, maybe a fight song for a pep rally, but that the school doesn't use the gym for dances or an after-school club with rap, hip-hop and EDM. Ok, so there's no need for subs, or 15's or even 12's, and you maybe better off considering 10", 8", even 6.5" or an array of mini's, as long as the goal of pattern control is kept in mind.

To recap, I've suggested:

Acoustic treatment -- but not just brute force, figure out what frequencies can be addressed to deliver the best result for the least effort, and consider shapes, materials and surfaces and not just absorbing panels.

Hi-Q speakers -- the good stuff is big bucks, but there's some CBT arrays and coaxial horns within your budget.

Placing and aiming the speakers -- consider the details of the room and the audience and the necessity to balance quantity, placement, aim and pattern control of the loudspeaker(s) for the maximum direct-to-reflected ratio.

Roll off low frequencies -- you'll gain intelligibility for speech and articulation for music.
Old 14th March 2017
  #33
Lives for gear
 

Quote:
Originally Posted by Calneva View Post
I was hoping someone would actually start to take a crack at a solution for the OP. Here's something the OP can use.
What would be the point of this exercise?

We don't have the details to make and educated guess and speculative generalizations will be just that...speculative generalizations which may, or may not be helpful.

It's a lot more helpful to the OP if we guide guide him in his quest to choose the right contractor for the job. Guessing what speakers to use...in a room we know nothing about...or how the job should be done when we don't know the specifics of the project is meaningless especially since he will not be doing the job and just need to help the school choose a contractor.
Old 15th March 2017
  #34
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mojo filters's Avatar
 

I don't see the point in speculating about specific product types. The room plus the type and volume of the programme material as described here, isn't enough to make such a determination. For all we know a 100V line distributed system with granular zone control plus an induction loop may be what's needed to fulfill the OP's room's requirements.
Old 15th March 2017
  #35
Here for the gear
 

You know, I feel that the type of installs most of the replies are looking to do would be for the quality one would expect in a concert area (acoustically speaking). Its a school gymnasium, likely no one will really care about pristine sound quality when blasting music ripped from YouTube of their smart phones. Certainly the safety and reliability of the install is paramount, however, I am sure you could compromise on the sound to some degree.
Old 15th March 2017
  #36
Gear Head
 

Quote:
Originally Posted by mojo filters View Post
I don't see the point in speculating about specific product types. The room plus the type and volume of the programme material as described here, isn't enough to make such a determination. For all we know a 100V line distributed system with granular zone control plus an induction loop may be what's needed to fulfill the OP's room's requirements.
An induction loop....in a gym? I think not. It's not a requirement and it would be beyond the budget of the average public school.
Old 15th March 2017
  #37
Gear Maniac
 

Quote:
Originally Posted by Samc View Post
What would be the point of this exercise?

We don't have the details to make and educated guess and speculative generalizations will be just that...speculative generalizations which may, or may not be helpful.

It's a lot more helpful to the OP if we guide guide him in his quest to choose the right contractor for the job. Guessing what speakers to use...in a room we know nothing about...or how the job should be done when we don't know the specifics of the project is meaningless especially since he will not be doing the job and just need to help the school choose a contractor.
C'mon guys . . . Calneva does have a point -- it's a freakin' high-school gymnasium! We all have a pretty clear of it's general size, shape, use, and acoustics . . . even its odor. It's overwhelmingly likely to be a rectangular echo-box arranged around a basketball court, with a combination of pull-out and/or fixed hard terraced benches on either one or both long walls. Given that the OP has indicated that they are indeed going to use a proper contractor for the design and installation . . . that point has been driven into the ground here . . . it's not unreasonable to put some ideas out there of the sorts of things one might find in the proposal from one, just as a point of reference.

In most of the high-school gymnasiums (gymnasia?) I've seen, the overwhelming mistake in sound-system design is to use loudspeakers that have poor or unsuitable directivity characteristics ("pattern control") for the room. The second issue is that of excessive overlap in coverage of seating areas from different loudspeakers. Both of these are problems that will bite you far more severely in a highly-reverberant environment than in one that's even slightly treated.

For avoiding this, my advice would be to make sure that the contractor has done an appropriate simulation of their loudspeaker design in an industry-standard application such as EASE, and doesn't stare back blankly or get defensive when asking for a quantitative analysis of where the loudspeakers go, and what areas they're supposed to cover.

More specifically, my personal starting point for an entry-level system design in this sort of room would be a center "spherical" cluster of passive JBL PD5000/6000 boxes, either single-sided or double-sided depending on whether or not the room has bleachers on both or one long wall. This helps eliminate issues with coverage overlap, and improves low-frequency directivity as the boxes can work together. Amplifier and processing channel count can be kept low if necessary for the budget, and it's straightforward to calculate the weight and rigging requirements, and pull speaker cable to one point with no AC required. It's also possible to get cute with processing for a double-sided array, allowing one side to produce a quasi-cardioid LF pattern for the other side if only one side is in use for smaller events.

Alternatively, I might look at one or two linear rows of the same PD boxes to cover the seating areas (either singles or main/downfill pairs depending on room geometry) . . . this would have the advantage of more consistent coverage and better voice intelligibility going into the corners of the room. Tradeoffs would be poorer overall LF control, and more money as it usually takes more boxes to get proper coverage. This might be the route I'd go if the room was on the long/narrow side for a gymnasium, and the application was heavily weighted towards spoken word over music. But I would NOT then use cheaper/smaller boxes with poorer pattern control to bring the cost back down . . . it's very infrequent indeed where quantity can make up for quality, especially in a very live room.
Old 15th March 2017
  #38
Lives for gear
 

A contractor who treats your project like a generic install and already has a formula for what to do and what to use is exactly the contractor who shouldn't get the job.

Get someone who will give your project the attention it needs and who is willing to look outside the formulaic approach to designing your system.
Old 16th March 2017
  #39
Gear Nut
 

Quote:
Originally Posted by rosesk25 View Post
Its a school gymnasium, likely no one will really care about pristine sound quality when blasting music ripped from YouTube of their smart phones.

Quote:
Originally Posted by bhandy View Post
An induction loop....in a gym? I think not. It's not a requirement and it would be beyond the budget of the average public school.
The trouble is you're assuming the gymnasium is only going to be used for gym. Certainly where I went to school, the gymnasium was used for all sorts, from performances to assemblies to presentations to external hires.

So assuming it doesn't need good sound quality or an induction system is very short sighted. At best, it proves why the OP needs to supply more information.
Old 2 days ago
  #40
Gear Head
 

Quote:
Originally Posted by de003 View Post
The trouble is you're assuming the gymnasium is only going to be used for gym. Certainly where I went to school, the gymnasium was used for all sorts, from performances to assemblies to presentations to external hires.

So assuming it doesn't need good sound quality or an induction system is very short sighted. At best, it proves why the OP needs to supply more information.
Hearing assist devices are not a requirement in those spaces....even if it is a gymnatorium. The primary function and construction of the room dictates. Since the OP was being consulted for this school job, and he is not a CTS, or legal contracting business, we can assume the school is not concerned about such things.
Old 2 days ago
  #41
Gear Head
 

Quote:
Originally Posted by Samc View Post
A contractor who treats your project like a generic install and already has a formula for what to do and what to use is exactly the contractor who shouldn't get the job.

Get someone who will give your project the attention it needs and who is willing to look outside the formulaic approach to designing your system.
This is not really fair. If a contractor does mostly schools and school gyms, and these buildings rarely differ greatly, it's not really rocket science for them. They will have a large portfolio of similar jobs. I will even go so far as to say, if a contractor is given a budget, and can't whip out a proposal within 10 minutes, with a probable cost, then you have the wrong contractor. In the K12 world, those spaces don't vary enough to require from the ground up engineering, especially for a seasoned contractor. I have done gyms in a school system where all buildings are exactly the same. The OPs could be one like that. We don't know. Someone could walk in, whose done the others, and provide a good solution quickly.
Old 2 days ago
  #42
Lives for gear
 

Quote:
Originally Posted by bhandy View Post
This is not really fair. If a contractor does mostly schools and school gyms, and these buildings rarely differ greatly, it's not really rocket science for them. They will have a large portfolio of similar jobs. I will even go so far as to say, if a contractor is given a budget, and can't whip out a proposal within 10 minutes, with a probable cost, then you have the wrong contractor. In the K12 world, those spaces don't vary enough to require from the ground up engineering, especially for a seasoned contractor. I have done gyms in a school system where all buildings are exactly the same. The OPs could be one like that. We don't know. Someone could walk in, whose done the others, and provide a good solution quickly.
Arriving at a good solution quickly is not the problem, any reasonably experienced person can eyeball a situation and come up with an estimate...if the estimate is even close to reality is another story. Using a formulaic approach is BS in my opinion, because even if two rooms are constructed exactly alike, little things like how the rooms will be used can make a difference, you still have to pay attention to details.
Old 2 days ago
  #43
KEL
Lives for gear
 

The OP went MIA on this thread over a month ago. Gee, I wonder why... I think wyllys answered most thoughtfully in the first couple posts.
Old 2 days ago
  #44
Gear Head
 

Quote:
Originally Posted by Samc View Post
Arriving at a good solution quickly is not the problem, any reasonably experienced person can eyeball a situation and come up with an estimate...if the estimate is even close to reality is another story. Using a formulaic approach is BS in my opinion, because even if two rooms are constructed exactly alike, little things like how the rooms will be used can make a difference, you still have to pay attention to details.
Again...if you select a contractor that does a large number of these, they will likely have one in their portfolio that is a near match. The only thing that changes for us from site to site is budget.
Old 2 days ago
  #45
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mojo filters's Avatar
 

Quote:
Originally Posted by bhandy View Post
Again...if you select a contractor that does a large number of these, they will likely have one in their portfolio that is a near match. The only thing that changes for us from site to site is budget.
Every customer has identical requirements?

I find it hard to believe budget is the only aspect that determines how you deal with superficially identical rooms, as the only differentiating factor...
Old 2 days ago
  #46
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Quote:
Originally Posted by bhandy View Post
The only thing that changes for us from site to site is budget.
This makes you the wrong type of contractor for any project I'm working on...I happen to know that not all contractors operate like that.

I've mixed hundreds of reggae bands over the years, does this mean I should have a mix ready even before hearing the next band I mix?
Old 2 days ago
  #47
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Quote:
Originally Posted by KEL View Post
The OP went MIA on this thread over a month ago. Gee, I wonder why...
Who cares...should everybody abandon a thread when the OP stops posting? Are threads supposed to serve the original posters only, can the rest of the community not learn without the OP's involvement?

It's very clear to everyone here that the OP haven't posted in awhile, so what was the purpose of your post? I don't see anyone being forced to be here.
Old 2 days ago
  #48
Gear Head
 

Quote:
Originally Posted by Samc View Post
This makes you the wrong type of contractor for any project I'm working on...I happen to know that not all contractors operate like that.

I've mixed hundreds of reggae bands over the years, does this mean I should have a mix ready even before hearing the next band I mix?
If you think schools have the money to do things perfectly, as audio engineers would have it, you are not working in reality. Schools are underfunded, and the majority of money coming in for sports stadiums, gym overhauls and equipment is from outside sources. But my point with my budget was relative to the caliber and quality of the gear used. For instance, if the school cannot afford Shure QLXD wireless, we have to make concessions and move down the food chain. If the school cannot afford the digital mixing system they would really love to have, maybe they have to dumb that down with an analog solution. THAT is what I meant about budget. I just did a system where the theater teacher wanted 16 channels of wireless. They just didn't have the budget for what I would know would be the most robust option, they had to go with a lesser expensive MiPro system. I would love to sell them a system for a professional environment. At the end of the day, money is the big deciding factor for most people, most of the time.
Old 2 days ago
  #49
KEL
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Quote:
Originally Posted by Samc View Post
Who cares...should everybody abandon a thread when the OP stops posting? Are threads supposed to serve the original posters only, can the rest of the community not learn without the OP's involvement?

It's very clear to everyone here that the OP haven't posted in awhile, so what was the purpose of your post? I don't see anyone being forced to be here.
OK, fair enough. that sounds very noble & admirable, lets educate the community. Tell the community what you've learned? Or, is the "community" everyone but you?
Old 1 day ago
  #50
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Quote:
Originally Posted by KEL View Post
OK, fair enough. that sounds very noble & admirable, lets educate the community. Tell the community what you've learned? Or, is the "community" everyone but you?
The community, (or some, members of the community) are voluntarily educating themselves through discussion...nobody is forced to be here and I don't see the point of coming here to tell the rest of us that the OP haven't posted in a month.

Should the rest of us stop posting and the thread forgotten? Just don't know what is your point...or even if there is one for that matter.
Old 21 hours ago
  #51
KEL
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"It's a lot more helpful to the OP if we guide guide him in his quest to choose the right contractor for the job."
Old 17 hours ago
  #52
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Quote:
Originally Posted by KEL View Post
"It's a lot more helpful to the OP if we guide guide him in his quest to choose the right contractor for the job."
You're grasping at straws now, this line from a previous post is totally out of context, but, this is exactly what we were attempting to do...in case you didn't notice we were discussing the right type of contractor for the job.

You took the time to come here and advise us of the obvious...apart from trying to derail the thread, were you trying to make a (helpful) point? What is it?
Old 11 hours ago
  #53
Gear Nut
 

Quote:
Originally Posted by KEL View Post
"It's a lot more helpful to the OP if we guide guide him in his quest to choose the right contractor for the job."
Sorry to be abrupt but you're being a bit of a dick about this.

What is your problem?
Old 8 hours ago
  #54
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mintaka007's Avatar
The frustration comes from 2 things.

The first is SAMC's condescending manner in which he posts and approaches subjects. If you will notice, in his mind he is ALWAYS correct and ALWAYS the expert. This puts many people, including myself off.

The second is the reality of budget. As one of the other posters pointed out, there might be an optimal system to sound best for this room and for the intended use, but the budget might be no where near that system.

I see plenty of old 80's peavey unpowered speakers meant as small room speakers being used in school auditoriums because of budget issues (not to mention they sound like butt.)

At a time when they are cutting entire music programs because of budget constraints, arguing over which prolevel speaker will sound best regardless of budget is ignorant and ridiculous

In this instance, budget Is THE first variable to look at, as it is a finite and unwavering #. This is SAMC's Blindspot, and that other contractor on here pointed it out. Will SAMC acknowledge this? Of course not. He is never wrong. He will come back in a post that follows and justify his position in his own mind, which is totally fine. I learned a while ago that most of what he says is knowledgeable within his window of market, but he lacks the ability to adapt to other limiting situations. I live in the area of limiting situations, so his input is rarely helpful.

That is what frustrated others on here, has frustrated droves of people in the past and will continue to frustrate in the future.

Just post your opinion to best help answer the query at hand, and ignore SAMC when he tells you why you are ignorant and wrong. This is by far the easiest way I have found to make this forum helpful and useful. There are a couple other grumpypusses on here as well, and I apply this philosophy to them also. Makes the site much more pleasant and enjoyable.

Last edited by mintaka007; 7 hours ago at 05:20 PM..
Old 7 hours ago
  #55
KEL
Lives for gear
 

Admittedly, I was being sarcastic, and unhelpful on these last handful of posts. Along with others, I offered my thoughts over a month ago. There were good nuggets of advice already- contract it out, make it safe, check on the quality of work. The op posted once I believe. The thread had sort of run its course.

. Bhandy picked it up again after a month of dormancy. My intuition is such that I believe Bhandy does this very thing professionally. I agree with his thoughts for the most part, so if you find something to ask or get clarification about, go ahead, and add your experience and reasonings why you might not have the same opinions. But, to label his ideas as BS, "cookie cutter" to mention this kind of contractor is precisely the wrong choice, etc? Really, based on a couple paragraphs? I don't think he was offering the bible on the topic. Talk about taking things out of context. Sorry, thats not educational, helpful, nor anything new, hence my post about the OP being M.I.A.

It's an easy way to deflect what was happening by taking a noble stance "it's benefitting the community" when it wasn't . But that's my opinion. And just as I could have not posted, my sarcastic question "gee, I wonder why?"(the op hasn't posted), it wasn't aimed at Sam, I think he felt like it was, which is sort of telling. This kind of escalation happens frequently with his participation.
Old 7 hours ago
  #56
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Quote:
Originally Posted by KEL View Post
Admittedly, I was being sarcastic, and unhelpful on these last handful of posts.......................................And just as I could have not posted, my sarcastic question "gee, I wonder why?"(the op hasn't posted), it wasn't aimed at Sam, I think he felt like it was, which is sort of telling. This kind of escalation happens frequently with his participation.
Lets see, you come here and make a series of posts that even you admitted were unhelpful and useless, not to mention snarky, and then blame someone else for making trouble when you get called out for it...there's a name for this.

There was a healthy discussion going on until you, and Mr. yahoo joined in with your personal attacks I might add...now that's telling.
Old 6 hours ago
  #57
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mojo filters's Avatar
 

I don't understand how some folks just can't cope with the regular cut and thrust of a healthy debate?

Why is it that when certain people decide they disagree with someone like Sam, they seek to further their argument through turning to personal insults, accusations of arrogance, and so forth, rather than sticking to the subject at hand?
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