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[Masis Ingilizian]

I am an amatuer when it comes to PA, and have read a little on the difference between line array vs point source. I am also new to this forum but have been around other forums for a while. My goal is to match the acoustic treatment for the large venue I am working on with the intended speakers. Put it this way, I don't trust the audio engineer(they just sell PA systems, not experts) and am making sure we or shall I say he chooses the right dispersion pattern.

The room is 17 metres from front to back and 23 metres left to right with the lowest part of the ceiling height 5m closer to the stage with it inclining to 9.6m to the back of the hall like a vaulted ceiling. It is intended for live music as well as DJ, it a wedding hall.

I am considering toeing in the speakers to criss cross the room, to get later reflections from the opposite side walls which might or might not have diffusion on the wall. The back is glass in the middle and on the sides concrete but I will fill up on that part of the back wall with heaps of absorbtion.

My understanding is a 80 to 90 degreee horizontal coverage will aim the speaker to the opposite side covering the dance floor and reducing or essentially getting rid of the closest side wall reflection. A line array has 100 degree horizontal pattern plus from what i understand it throws the music as far as it can, and with a glass wall on the back it wont be ideal. The room is about 3000m3 and defenitely has a higher RT60 of 5ms but im not experienced enough to take a decent guess, the place was an echo chamber. I will be bringing that down to at least 2ms, well I am going to try.

https://photos.app.goo.gl/aFRBTeQxeBpMNrRi7

Let me know if the attached link for the photos work. When clicking on the insert image, all i got was a quoted "img" and was not sure how to attached them into the post.

[Steve-White]

Butter heating up and Popcorn popping.

Welcome to the forums sir - fasten your seatbelt and stow all items.

[Masis Ingilizian]

Butter heating up and Popcorn popping.

Welcome to the forums sir - fasten your seatbelt and stow all items.

Thanks mate, I was attracted here by the quality articles on the website. I am actually into small room acoustics althouh I have read enough internet available papers on larger venue acoustics still getting my head around the differences. I also have a triamped DSP system for home but as I am the acoustic "expert" in town I get odd jobs regardng acoustics and on this occasion promised the owner I check up on the audio engineers choice for the hall. The audio engineer recommended the JBL VRX series which line array or a concave curvature array and my knowledge tells me that a point source will be a better option for this particular hall. So hopefully some of the experts can chime in and tell me what I am looking for.

[Matthias McCready]

Thanks mate, I was attracted here by the quality articles on the website. I am actually into small room acoustics althouh I have read enough internet available papers on larger venue acoustics still getting my head around the differences. I also have a triamped DSP system for home but as I am the acoustic "expert" in town I get odd jobs regardng acoustics and on this occasion promised the owner I check up on the audio engineers choice for the hall. The audio engineer recommended the JBL VRX series which line array or a concave curvature array and my knowledge tells me that a point source will be a better option for this particular hall. So hopefully some of the experts can chime in and tell me what I am looking for.

That is a small space for a line array, which would certainly cost more without necessarily offering better performance.

Regarding the engineers suggestion of VRX boxes. That is a constant curvature box (ie no adjusting angles between boxes). The tonality of them is not great, and their coverage pattern is quite inconsistent (Horizontally in the boxes coverage the horn/mid driver is not even). They are not "delightful" to work on, the best I can give them, is that they "get the job done."

An appropriate point-source product (pick your brand) would probably work well for this venue; if they are deadset on the look of an "array" the room is more sized for a constant curvature box (again much more money than point source).

The only constant curvature product I have worked on that I have enjoyed (good tonality, even coverage, nice handoff between boxes) is the install version of L'Acoustics A series (I did not like the tour version of that product, as the handoff from box to box had problems).

[Jeremy Young]

I am by no means an expert, but I spent a lot of time asking questions until I finally picked up and read Bob McCarthy’s book Sound Systems: Design and Optimization.  I’ve read several other resources, but none as complete and detailed as that one.  Literally every question I used to ask was answered in detail.  I can’t recommend it enough.   Go grab a copy, read it start to finish, and you will find the exact answers to your question with formulas and charts to do the calculations, along with real world venue examples.

This forum is great, but to truly understand (to the level needed to provide counter arguments to an engineer on a permanent install) everything from the basics to optimization, there’s a lot of reading needed to get there. 

Line arrays (should) be designed through the manufacturers prediction software so that you can implement the necessary splay angles and processing.  Line arrays and point source both come in a range of available horizontal dispersion angles, and placement / trim height needs to be calculated for both based on numerous details not included in your original post. 

Since we’re in a virtual environment, my tone is meant in a helping way, not trying to cut you down for asking good questions or not including the right data.  I just can’t help but preach how many “ah-ha” moments I had reading that book and am convinced it will help you. 

Good luck on your project !

[Mike Caldwell]

I looked at the room pictures and I'm surprised the RT60 is only 5 sec (I assume you mean 5 sec, you have it posted as 5ms  milliseconds)
Nothing in that room with a 5 sec. RT60 would sound good, if you can get it down to 2 sec. you will be doing good.
Will the designers of the room allow you to do that much room treatment?

[Masis Ingilizian]

That is a small space for a line array, which would certainly cost more without necessarily offering better performance. 

Thanks, I was under that impression as well. A point source can spray onto the dance floor while still covering the entire hall but with a slightly reduced SPL for the seated guests if I slightly toe in the speakers aiming to the dance floor might work.

Regarding the engineers suggestion of VRX boxes. That is a constant curvature box (ie no adjusting angles between boxes). The tonality of them is not great, and their coverage pattern is quite inconsistent (Horizontally in the boxes coverage the horn/mid driver is not even). They are not "delightful" to work on, the best I can give them, is that they "get the job done."

Can you explain no adjusting angles between boxes? I think what you mean is that you need more boxes to get vertical coverage which will end up costing more and you can't play around with it like a point source.

The only constant curvature product I have worked on that I have enjoyed (good tonality, even coverage, nice handoff between boxes) is the install version of L'Acoustics A series (I did not like the tour version of that product, as the handoff from box to box had problems)

Appreciate the recommendation but if point source is better than its simple enough to find a point source speaker. I am thinking around 90 by 60 degree coverage, I can go smaller but I will loose directivity with the higher frequencies so perhaps stick to a 90 by 60 ish coverage pattern?

An appropriate point-source product (pick your brand) would probably work well for this venue; if they are deadset on the look of an "array" the room is more sized for a constant curvature box (again much more money than point source).

Well, how do I put this. I'm not deadset in any way, I am just ensuring the audio engineer is choosing the appopriate gear. He mentioned JBL VRX and the QSC line. So perhaps he works with those companies and would like to sell them, now whether he is deadset on those brands I am not sure yet, I will know when I discuss with him. The QSC has some conical horns which I do not know enough about but I am sure they have enough in there range to find something appropriate.

I figured out how to use Ease Focus but all it does is give a basic coverage pattern which is great but not taking in consideration room modes and reflections I do not see the point. I used a QSC AP 5122 to simulate and I get decent dance floor coverage what else do I need to look at to understand if the speaker is a decent choice? Sorry basic question but it will point me in the right direction.

[Mike Caldwell]

I'm not going say one type of speakers over another however your most likely going to want/need some fill speakers in the side sections. Those could be on a different zone/mix
to control the level and the program content being sent to them independent of the main
system.

Is there going to be a house sound person to run the system, will full production services be offered, stage monitors, mics, cables, stands and all the parts and pieces needed put on an event?

[Masis Ingilizian]

I am by no means an expert, but I spent a lot of time asking questions until I finally picked up and read Bob McCarthy’s book Sound Systems: Design and Optimization.  I’ve read several other resources, but none as complete and detailed as that one.  Literally every question I used to ask was answered in detail.  I can’t recommend it enough.   Go grab a copy, read it start to finish, and you will find the exact answers to your question with formulas and charts to do the calculations, along with real world venue examples.

Definiley will purchase that book.

This forum is great, but to truly understand (to the level needed to provide counter arguments to an engineer on a permanent install) everything from the basics to optimization, there’s a lot of reading needed to get there.

I know and each sub branch that you divert into although overlapping is its own science. Its the never ending quest for knowledge. Anyway, this thread was an attempt to serve as a speed training course for the basics.

Since we’re in a virtual environment, my tone is meant in a helping way, not trying to cut you down for asking good questions or not including the right data.  I just can’t help but preach how many “ah-ha” moments I had reading that book and am convinced it will help you.

Appreaciate it. I myself try and reply to threads on forums to continue that cycle of the new generation also making an effort to educate the even newer guys. Any reply is apprecaited, I do have heaps of questions but I will try and grasp a concept than ask what I don't get.

Line arrays (should) be designed through the manufacturers prediction software so that you can implement the necessary splay angles and processing.  Line arrays and point source both come in a range of available horizontal dispersion angles, and placement / trim height needs to be calculated for both based on numerous details not included in your original post.

Well, I got the hang of Ease Focus but like i mentioned above I don't see it as the perfect software as it doesn't take in consideration room modes, SBIR and other interference. Its free, I picture the spray but is there something I am missing or is that just it?

[Masis Ingilizian]

I looked at the room pictures and I'm surprised the RT60 is only 5 sec (I assume you mean 5 sec, you have it posted as 5ms  milliseconds)
Nothing in that room with a 5 sec. RT60 would sound good, if you can get it down to 2 sec. you will be doing good.
Will the designers of the room allow you to do that much room treatment?

I haven't measured it yet, 5 sec was my estimate. Are you saying that it would be even higher than 5 sec in that hall? I would really like to know so I can simulate in amacoustics tool to see how much absorbtion I really need covered.

Yes, my mistake with 5ms apologies.

I will meet with the owner and designer for a prelimanary layout with all the pertaning options. His keen, but I haven't flopped out prices yet so it could go either way. In terms of how much treatment we can add keeping the aesthetics, I agree with you that it will be difficult. I mean if we take a ball park figure of 1000m2 coverage needed I dont even think I will manage close 400m2 which really won't make a dent in the RT60 time.

The only way is the Aqflex but I have no idea how expensive they are. Anyone have any idea? I read a research paper called "A survey of reverberation times in 50 Europeanvenues presenting pop & rock concerts" which has a conclusion based on the Aqflex tubes and mentions decent reduction in reverberation times especially in the 60 to 500hz range. If this is too expensive I doubt he will allow a drywall on the ceiling to fill up with soft fluffly stuff with a 50cm gap but I will defintely recommend it as the next best option.

[ProSoundWeb Community]