Grain Silo Listening Room

[BGrothoff]

Hey All!

I’m finishing out the first floor of a 21’ diameter silo for a listening room/home studio. I haven’t been able to find much on the web regarding acoustics for a round room, so I’m struggling with the design. The walls are insulated, 2 x 6 x 8’ tall, and the floor is concrete, with an inside diameter of 19’ 8”. Exterior walls are 12 gauge steel. I’m trying to figure out what would be the best choices for the walls, ceiling and floors. I’ve got access to very cheap custom acoustic fabric wall panels, so I was thinking of covering the walls and ceilings with 1” or 2” thick acoustic panels covered in either fabric or vinyl. I was also thinking of a wood floor so the room is not quite so dead. I haven’t done anything yet so the room is a blank canvas!

The room will have an acoustic drum set, electric guitar and a set of Zaph SR-71’s for listening. There will probably be a couch in the room and a desk as well. There is one small window, and a 4' x 6'8" door that could be covered with fabric as well.

I’m kind of a noob when it comes to acoustics, so any advice would be greatly appreciated!

Thanks!

 

[TLS Guy]

Well we have had small basement concrete rooms akin to public lavatories and now this.

Unfortunately this bin, will be a bin job. It will be acoustically awful. For one thing the galvanized walls will flex and cause all sorts of response irregularities. The bigger problem is that all horizontal reflective time paths will be identical, and sum to a horrible mess.

I absolutely would not invest any time and money in this hair brained project.

 

[BGrothoff]

Hey TLS,

Thanks for the quick reply. I don't really have any other place for the project so the silo is going to have to do. Will the wall/ceiling/floor coverings do nothing to improve the acoustics? The walls could have acostic fabric -> 2" acoustic panels -> 1/2" or 1" acoustic drywall -> 2x6" insulated walls before the sound would reach the steel shell to be reflected back. A similar approach could be taken with the ceiling and the floor could be carpeted and padded if needed. Is there nothing that can be done to make the space sound reasonable?

Forgive the stupid questions, like I said I'm new to this. I can get acoustic panels made by a customer of mine for very cheap, possibly free. I can cover as much of the interior walls as neccisary to achieve good results, if good results are possible.

Thanks,
Brett

 

[macddmac]

19' diameter leaves room to frame into a shape (rectangle)more amenable to listening.
You could use the area outside the new walls for storage.
Cheers, Mac

 

[TLS Guy]

Hey TLS,

Thanks for the quick reply. I don't really have any other place for the project so the silo is going to have to do. Will the wall/ceiling/floor coverings do nothing to improve the acoustics? The walls could have acostic fabric -> 2" acoustic panels -> 1/2" or 1" acoustic drywall -> 2x6" insulated walls before the sound would reach the steel shell to be reflected back. A similar approach could be taken with the ceiling and the floor could be carpeted and padded if needed. Is there nothing that can be done to make the space sound reasonable?

Forgive the stupid questions, like I said I'm new to this. I can get acoustic panels made by a customer of mine for very cheap, possibly free. I can cover as much of the interior walls as neccisary to achieve good results, if good results are possible.

Thanks,
Brett

You don't understand. You can make it dead. You need reflections. A dead room sounds terrible. You need a wide variety of reflections and arrival times. To sound any good there must be a dominant dimension. Rectangles are best. Square (cuboid) rooms sound awful as well.

The previous poster, macddmac, has the right idea. You need to build a rectangular room inside the silo. You must understand how totally awful your current conception will sound. It is not redeemable, except along the lines suggested by macddmac.

 

[BGrothoff]

I'm beginning to understand. Could I start with a dead room and add reflective surfaces? I'd hate to put a rectangle inside the room, it would reduce the space by more than half. I understand that might be the most practical answer. How about adding flat sections that are reflective at key points? Like making a rectangle with very rounded corners? Is there some way to model this on a computer? Still have to do something with the standing waves between the ceiling and floor, but that seems like a more common problem solve.

 

[TLS Guy]

I'm beginning to understand. Could I start with a dead room and add reflective surfaces? I'd hate to put a rectangle inside the room, it would reduce the space by more than half. I understand that might be the most practical answer. How about adding flat sections that are reflective at key points? Like making a rectangle with very rounded corners? Is there some way to model this on a computer? Still have to do something with the standing waves between the ceiling and floor, but that seems like a more common problem solve.

Acoustic modeling is very complex and expensive. With all the expense of trying to put this right, you could build a luxury home with a dedicated home theater.

But I can tell you when you have a dog of a room it is always a dog. The best example I can thing of is the Royal Festival Hall on the South bank built after WW II. The architect over ruled that acoustic engineers and came up with unfortunate dimensions.

Over the years millions have been spent trying to rectify it. The last attempt was a really expensive remodel to actually move walls and change the shape of the building a bit. It is still a dog. It is an absolute acoustic pig.

 

[Armandhammer]

Just curious...what would be a good room dimension for a listening room? Or a ratio if actual size doesn't matter? I'm hoping to be in a new house this spring and it will have an unfinished basement and about half will be mine to do with whatever I want. About a 25'x25' area (not a very big house obviously) but part of that will have to be used for my work shop for my bikes (mountain and road bikes).

 

[Robert Couch]

Hey All!

I’m finishing out the first floor of a 21’ diameter silo for a listening room/home studio. I haven’t been able to find much on the web regarding acoustics for a round room, so I’m struggling with the design. The walls are insulated, 2 x 6 x 8’ tall, and the floor is concrete, with an inside diameter of 19’ 8”. Exterior walls are 12 gauge steel. I’m trying to figure out what would be the best choices for the walls, ceiling and floors. I’ve got access to very cheap custom acoustic fabric wall panels, so I was thinking of covering the walls and ceilings with 1” or 2” thick acoustic panels covered in either fabric or vinyl. I was also thinking of a wood floor so the room is not quite so dead. I haven’t done anything yet so the room is a blank canvas!

The room will have an acoustic drum set, electric guitar and a set of Zaph SR-71’s for listening. There will probably be a couch in the room and a desk as well. There is one small window, and a 4' x 6'8" door that could be covered with fabric as well.

I’m kind of a noob when it comes to acoustics, so any advice would be greatly appreciated!

Thanks!

 

[Robert Couch]

I hope you have not been completely demoralised by the replies but I find things often not as bad as predicted if you have the time experiment with your hi-fi and drum kit see how bad you think it is, compare headphone quality to acoustic ect. My hearing was damaged working with live bands back in the 70's and 80's so I'm no expert but with such a blank canvas I'd be tempted to play be optimistic trust your Gods

 

[TLS Guy]

I hope you have not been completely demoralised by the replies but I find things often not as bad as predicted if you have the time experiment with your hi-fi and drum kit see how bad you think it is, compare headphone quality to acoustic ect. My hearing was damaged working with live bands back in the 70's and 80's so I'm no expert but with such a blank canvas I'd be tempted to play be optimistic trust your Gods

And your evidence? Dance with the devil more like!

Just curious...what would be a good room dimension for a listening room? Or a ratio if actual size doesn't matter? I'm hoping to be in a new house this spring and it will have an unfinished basement and about half will be mine to do with whatever I want. About a 25'x25' area (not a very big house obviously) but part of that will have to be used for my work shop for my bikes (mountain and road bikes).

These dimensions are well known and studied.

This is a good article: - Room Dimensions for Small Listening Rooms.

The best room dimensions.

A square room is also a bad one as you will see. Why don't you put the workshop in the silo? That would be a much better idea.

I planned my room with optimal ratios and it sounds very good indeed.

 

[ski2xblack]

Agreed w/ the assessment of round rooms. Just bizarro echo chambers.

Question for the guys: If you frame out a room within a room, does it necessarily have to be rectangular? Trying to think outside the box, since the base situation is highly unconventional. Disregarding added costs for a minute, a trapezoid shape or staggered walls may work, thus better utilizing available space while (hopefully?) being not so acoustically unfavorable. Thoughts?

 

[Armandhammer]

And your evidence? Dance with the devil more like!


These dimensions are well known and studied.

This is a good article: - Room Dimensions for Small Listening Rooms.

The best room dimensions.

A square room is also a bad one as you will see. Why don't you put the workshop in the silo? That would be a much better idea.

I planned my room with optimal ratios and it sounds very good indeed.

Sorry to confuse...I'm not the one with the silo. I was just piggy backing a question off the OP since it was relative. We are hoping for a new house this spring. Dimensions will be approximately 50'x25' on a full basement. Half the basement is earmarked for a family room. That leaves the other half for me. My main hobby is cycling and I need a place to work on/store my bikes. I may end up building a nice shed workshop for that purpose so that would give me most of the remaining area to play with. A small section may be turned into a storage area. But that's why I was asking about optimal room dimensions since I'd have a raw space to build. I'll read the links you provided. Thanks for the help.

 

[KEW]

I'm beginning to understand. Could I start with a dead room and add reflective surfaces? I'd hate to put a rectangle inside the room, it would reduce the space by more than half. I understand that might be the most practical answer. How about adding flat sections that are reflective at key points? Like making a rectangle with very rounded corners? Is there some way to model this on a computer? Still have to do something with the standing waves between the ceiling and floor, but that seems like a more common problem solve.

Take your system, a boombox, or whatever is the best sounding system you can, to the silo and check out the sound (and don't forget to crank it a little!). Take it back inside the house to a room with normal rectangle layout.
Let us know.

 

[BGrothoff]

Thank you all for the advice so far!

I believe you that the shape presents unnecessary acoustic challenges that could easily be overcome by building a different structure. I also understand that my vision of excellent acoustics may be simply unattainable given the dimensions of the room. Unfortunately, I'm pretty confident that my wife will not allow me to build yet another structure on the property for the foreseeable future, so it's either the silo or nothing. Right now my gear is in a unconditioned garage and if not moved will start to rusting in the spring. At this point I need to make the best of a bad situation. I was working in the silo before, and like everywhere else I had speakers in there. I didn't notice terrible acoustics, but the speakers where cheap JBL outdoor ones mounted near the ceiling and I didn't spend a ton of time in there. Right now the ceiling is exposed R-19 insulation, the walls are 2x6, insulated and covered with 1/4 luan. The floor is concrete.

I guess my question at this point is what could be done to make the best of this situation? Would changing the walls like the attached picture provide marked improvements in acoustics? How far could I cheat the walls out before sound quality would really suffer? I tried using the room rations from the spreadsheet above but nothing really fit.

Thanks again!
Brett


Brett

 

[GranteedEV]

THat looks like a much more successful plan. I would say however, that you don't need to build a wall on the front of the room (aside from a projection screen or the like). The front of the room should be as absorptive as possible, assuming direct radiating speakers.

 

[lsiberian]

Looks like a train wreck was saved.

 

[ski2xblack]

THat looks like a much more successful plan. I would say however, that you don't need to build a wall on the front of the room (aside from a projection screen or the like). The front of the room should be as absorptive as possible, assuming direct radiating speakers.

Instead of the drywall on the chosen front aspect, I'm picturing just enough structure to to hold / R30 denim insulation completely filling the void behind it. Maybe wrap it further around the flanking exposed curved wall sections too. If the OP has budgeted for finishing the room, this sort of stuff doesn't really change the equation too much.

Still not sure it will work. Thinking bass here. That 19' diameter will be a modal nightmare. A few drywall partitions won't make any difference, and I'm not sure you can stuff that room enough to take care of it either.

 

[Irishman]

Thank you all for the advice so far!

I believe you that the shape presents unnecessary acoustic challenges that could easily be overcome by building a different structure. I also understand that my vision of excellent acoustics may be simply unattainable given the dimensions of the room. Unfortunately, I'm pretty confident that my wife will not allow me to build yet another structure on the property for the foreseeable future, so it's either the silo or nothing. Right now my gear is in a unconditioned garage and if not moved will start to rusting in the spring. At this point I need to make the best of a bad situation. I was working in the silo before, and like everywhere else I had speakers in there. I didn't notice terrible acoustics, but the speakers where cheap JBL outdoor ones mounted near the ceiling and I didn't spend a ton of time in there. Right now the ceiling is exposed R-19 insulation, the walls are 2x6, insulated and covered with 1/4 luan. The floor is concrete.

I guess my question at this point is what could be done to make the best of this situation? Would changing the walls like the attached picture provide marked improvements in acoustics? How far could I cheat the walls out before sound quality would really suffer? I tried using the room rations from the spreadsheet above but nothing really fit.

Thanks again!
Brett


BrettView attachment 14475

Brett,

What are your room dimensions using the above plan?