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[g'bye, Dick Rees]

  Guys, Chuck Clark sent me in a direction to follow with some of his expertise in mind. I really have no preconceived ideas here. A center cluster would just be easier, but I would run the cabling in the crawl space and separate them, hang 3,4 speakers whatever. I think 3- 12s would give better coverage because of the width of the room. But thats what I think not what I know; thats why I am asking for input.

   

What needs to be determined is if and where there are any structural members which can support a properly flown set of speakers.  I know you're new here, so you may not be aware of the myriad discussions involving the necessity of having properly licensed, bonded and insured installers fly the speakers for you.  It is not a DIY job.  Likewise, the speaker themselves must be certified for flying as should all hardware involved.

You also mention running wiring in a crawlspace.  There are regulations and codes involving wiring run in such spaces, so you should comply with them as well.

[Ivan Beaver]

The larger diaphragms have a bit more output and tend to yield a bit more gain before feedback.

I'm sorry-but I just buy that.  Yes a large voice coil may be louder (at some freq)-but generally not across the freq range.  The lower end of the high freq may be louder-but due to the additional mass of the larger diaphragm-the higher freq tend to be not as loud-so they are actually quieter.  It is not a good idea to make general statements-unless there is more presented to back it up.

Do you have ANY evidence that a larger voice coil gives more gain before feedback?

In all of my years- in all of my discussions with industry people-this has NEVER come up.  I cannot see ANY way that this would make any difference.

It is NOT a good idea to spread things that simply are not true-unless you have some EVIDENCE to back it up.

I am always open to new thoughts and ideas-but this one is going to take some real convincing to get me to believe it-sorry.

[Ivan Beaver]

  . A center cluster would just be easier, but I would run the cabling in the crawl space and separate them, hang 3,4 speakers whatever. I think 3- 12s would give better coverage because of the width of the room.

The size of the woofers and the number of cabinets has NOTHING to do with the coverage of the cabinet.  And separating them (unless the proper cabinets are used-in the proper place and with proper processing) will actually NARROW the coverage-NOT widen it.

You HAVE to look at the REAL coverage (not the "simple" published numbers) of the cabinets-see how low this coverage goes in freq and so forth to begin to get an idea.

Because of the interactive nature of loudspeakers-the DO NOT behave as most people would like to "think" they would or as simple lines on a piece of paper do.

Just look at a line array-its pattern changes GREATLY due to the interaction between cabinets.

Just hanging speakers in the air and "hoping for the best" is usually a VERY BAD idea.

You might get lucky-but that is why people like Brad are in business-they go behind people who just "hang it up" and then actually DESIGN a system that works.

If you decide to take that approach-then be prepared to deal with the issues if it does not work.

It is far better to spend a little bit more money and do it right-than to spend some money-and then spend more money later on to do it right.

Loudspeaker system DESIGN is not a guessing game.  Yes-people who have been doing it a long time have a lot of experience (of good and bad installs-things that worked and didn't work) to base their opinions on.

As a general rule (and the way I start ALL of my designs) is I ask myself "Can I cover the space with a single loudspeaker and be loud enough"?

If I can do it with a single loudspeaker-then that is the way I go.  With loudspeakers (I don't care WHOS loudspeaker or model number) LESS is always going to sound better.

It may or may not be loud enough or cover the space properly-but that is the starting point.

Maybe a single speaker that covers 70% (or more) of the room and a couple of small fills for the rest.

And as Brad said-without more information about the room-where you CAN and CAN'T place loudspeakers is the FIRST thing you have to consider.  Without this information, any suggestion is pretty worthless (in my opinion), because it is based on information that is unavailable.

Let's say you want an opinion about a new car.  You can gets all sorts-but UNTIL you provide information about YOUR needs ( how many family members-do you need to pull a boat-how about hauling plywood or gas mileage needed) there is no way you can narrow it down to something that fits YOUR needs.

It really doesn't matter how good a sports car is-when you need to carry the wife and 4 kids.

Just something to consider.

[Ivan Beaver]

 

    The original install was 10 - 20 watt 8", 8 ohm overhead speakers; not only are there dead spots but I think they were damaged. When I came along they were all plugged into one side of a crown xls 402 pushed through a low-z install line. I somewhat balanced things by putting 5 into each channel and got rid of the low-z line.

  The room has a stage 20 deep 28 wide then the auditorium 38' deep for 58' over all, vaulted ceiling 14' peak and falls to 12' at the sides. Its fan shaped and maybe 5 degrees of slope on the floor. Be nice if I had blueprints? The speakers can be hung in front of the stage so there wouldn't be open mics unless someone went for a walk with one.

In a room like yours and for a service as described-then a distributed approach is a perfectly valid approach-IF you use enough loudspeakers.  Most distributed designs fail because not enough speakers were used.

Using a 70V approach is much better in this regard than using 8 ohm speakers.

What exactly was the "low Z" line that you replaced-and what did you replace it with? A High Z line?  Some more clarification is needed in that regard.

If there were some dead spots due to defective speakers-then don't blame the whole design.

If you start to hang the speakers in front of the stage-then knowing how close the audience is to the stage makes a HUGE difference on whether or not those speakers can be heard.  The vertical coverage is VERY important in this case-since they may have to be shooting straight down.

You say it is a "fan shape".  That means a lot of different things-and the people on the sides could be much closer to the stage (of BEHIND the loudspeakers) than the people in the middle.

How are those people going to hear?

[Brad Weber]

This can often be a situation where pictures are worth a thousand words.  And actually being in the space where you hear and see all involved can be worth a thousand pictures.
 
I think you will find that regardless of the budget or size of space or anything like that, given the opportunity, most pros would prefer to spend a good deal of time and effort trying to get to know the room, all the relationships within it, what you are trying to do and so on before they start to put together their own ideas for a system concept.  They'd likey try to gather as much input and information that might be relevant to the system design and installation as they can before starting to develop a conceptual solution to the the situation then defined.  So when you are asking for opinions from those who do not know the room or the conditions, the more information you can provide, the better they are able to respond.  Quite frankly, those who offer specific recommendations without such information can seem more interested in recommending something than in helping best serve you.
 
So before getting into what size low frequency drivers or voice coils or even more relevant issues like what pattern speakers, it makes sense to look at as many of the factors that may go into such decisions as possible such as where speakers can practically be located, what output levels are required, then intended use and proprities, what is the acoustical environment in which they'd be operating and so on.  Let that dictate the speakers then selected rather than the other way around.

[Cyrus Masters]

In a room like yours and for a service as described-then a distributed approach is a perfectly valid approach-IF you use enough loudspeakers.  Most distributed designs fail because not enough speakers were used.

Using a 70V approach is much better in this regard than using 8 ohm speakers.

What exactly was the "low Z" line that you replaced-and what did you replace it with? A High Z line?  Some more clarification is needed in that regard.

If there were some dead spots due to defective speakers-then don't blame the whole design.

If you start to hang the speakers in front of the stage-then knowing how close the audience is to the stage makes a HUGE difference on whether or not those speakers can be heard.  The vertical coverage is VERY important in this case-since they may have to be shooting straight down.

You say it is a "fan shape".  That means a lot of different things-and the people on the sides could be much closer to the stage (of BEHIND the loudspeakers) than the people in the middle.

How are those people going to hear?

  Thanks for your first response. That about sums up why I asked for suggestions in the first place. It may seem like I am putting the horse before the cart, but all that does is show my lack of knowledge/ experience on this. I feel as through after a series of rebukes that I am beginning to gather the right information to ask the question properly.

  I am not saying that there was a bad install done from the start. Over time the original equipment had been moved on from. The sound room was abandoned and a small rack mount system had been shoe horned into the pulpit. To access the house wiring a mic install line was used to feed back to the sound room. I had just moved the system back to the sound room and hooked up the speakers on the 2 channels of the amp back into the speaker distribution block. I think the speakers were damaged because of how they preform now; inconsistent from one to another, dead spots, and no range in them. Now given that to replace them for the same thing is $275 each and that would be for 70 volt speakers but the originals have no transformers they were just a 20w, 8ohm speaker. I think replacing them and rezoning the room with them would be more expensive and lots more work then finding a good speaker(s), cluster, array or whatever to put hang in the ceiling. The speakers used in the original install were Sound Advance Systems CT8BHSTFG oddly you can find a CT-8 from them on the web but not the model in the ceiling it must have been something available 10 years ago as a stripped down version.

[Ivan Beaver]

  Thanks for your first response. That about sums up why I asked for suggestions in the first place. It may seem like I am putting the horse before the cart, but all that does is show my lack of knowledge/ experience on this. I feel as through after a series of rebukes that I am beginning to gather the right information to ask the question properly.

  I am not saying that there was a bad install done from the start. Over time the original equipment had been moved on from. The sound room was abandoned and a small rack mount system had been shoe horned into the pulpit. To access the house wiring a mic install line was used to feed back to the sound room. I had just moved the system back to the sound room and hooked up the speakers on the 2 channels of the amp back into the speaker distribution block. I think the speakers were damaged because of how they preform now; inconsistent from one to another, dead spots, and no range in them. Now given that to replace them for the same thing is $275 each and that would be for 70 volt speakers but the originals have no transformers they were just a 20w, 8ohm speaker. I think replacing them and rezoning the room with them would be more expensive and lots more work then finding a good speaker(s), cluster, array or whatever to put hang in the ceiling. The speakers used in the original install were Sound Advance Systems CT8BHSTFG oddly you can find a CT-8 from them on the web but not the model in the ceiling it must have been something available 10 years ago as a stripped down version.

This is a good example of why detailed information is needed.

You said the room is "fan shaped".  In my experience-a "fan shaped" room looks very different than what you have drawn.  What you have is much easier to cover than a "fan shape" ( at least as far as people who do this for a living think of).

I have not seen any numbers for a budget.  That can be a big guiding factor.

There is NO reason even thinking about any speaker-unless there is money available for it.

Are we talking about $100 (yes I actually had a Church come to me for an upgrade and had $100 available and wanted a new system---) or $10,000 or something else?

You HAVE to have a target to shoot for.  Without that-it is a waste of time.

[Jerome Malsack]

With a 12 foot ceiling in the seating area.   The old speakers on the ceiling,
are the patrons seated all the time or standing some of the time. 

These changes will change the level of the audio heard because you will be adding 2 or 3 feet to a seated person from the speakers.   

What is the response of the speakers   100 hz to 12 khz.  ?? 

When working in a school gym I measured no pink noise above 8 khz from these overhead speakers at 25 ft.  So adding a driver and horn to boost this problem area in the room.   This will create another problem with time differences based on time of travel and speakers in rear of the ceiling. 

The answer for the gym may be a split into two systems  overheads for basketball and buzzers,  the second system will be stage, vocal/church/music. 

This brings us back to why Ivan is wanting good information to help design a better answer to build a one time solution. 

[Cyrus Masters]

With a 12 foot ceiling in the seating area.   The old speakers on the ceiling,
are the patrons seated all the time or standing some of the time. 

These changes will change the level of the audio heard because you will be adding 2 or 3 feet to a seated person from the speakers.   

What is the response of the speakers   100 hz to 12 khz.  ?? 

When working in a school gym I measured no pink noise above 8 khz from these overhead speakers at 25 ft.  So adding a driver and horn to boost this problem area in the room.   This will create another problem with time differences based on time of travel and speakers in rear of the ceiling. 

The answer for the gym may be a split into two systems  overheads for basketball and buzzers,  the second system will be stage, vocal/church/music. 

This brings us back to why Ivan is wanting good information to help design a better answer to build a one time solution.

 

  Most always people are standing for congregational singing and sitting for specials and preaching.
   
  Right now CT-8s spec out at 80Hz – 15kHz. I was wrong earlier about the cost of the same speaker replacement they are 175 each. I confused them with someones else 80w, 70 volt series.

  Unless what I have done something very wrong in having 5 on a channel of a crown xls 402. I know the ohm load is wrong it should only be 4 speakers, but it is the best I can manage right now. Sound quality while just playing a keyboard is not clear. The speakers seem to be bad and most likely should be not considered as usable going forward. Maybe the design is good and relevant and just should have the proper speakers installed.

 I am going to get pictures tonight and will include one of the ceiling layout. I hope that will give a complete overview of this. I was originally hoping to use the existing speaker system but discovered it is the biggest problem. 

[Jerome Malsack]

One of the options on the crown amps is to join the two channel amps in parallel to operate at lower Ohms ratings.   Was there a jumper wire from + to + on the two channels. 

Stereo two channel options. 

70 volt  Constant voltage systems as the third. 

Try and get the pdf of the manual for the amp from Crown.   

Check to ensure the polarity of the speakers are all the same.  You might be having speakers out of polarity causing cancellation effect.  Turning up the system will have little effect on raising the sound levels with speakers out of polarity.  2 speakers positive and 2 speakers negative will cancel the sound. 

[ProSoundWeb Community]