TLA
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Posts: 32
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Post by TLA on Mar 15, 2021 16:26:20 GMT
I'm working on a room in the GTA that holds a Grand Piano. Before Xmas, I finished 2 foot wide ceiling perimeter absorption with Guilford fabric installed. Inside the absorption perimeter the center of the Trusses will hold forty 2'x2' quadratic diffusers, targeting 1200hz to 8khz. The entire ceiling design was based on the fact that the ceiling is fairly low and the truss framing around the perimeter was an ugly mix of angles and directions that simply needed to be covered in a symmetrical way. but without lowering the ceiling. The owners are deciding on the type of wood, then all will be made in home shop.. The walls will be treated after piano is reinstalled and I can measure reverberation and possibly adjust things on walls only..
Any thoughts please?
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Post by Hexspa on Mar 16, 2021 13:35:01 GMT
I see you have two posts. Are they about the same room? Which thread would you like to keep?
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TLA
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Posts: 32
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Post by TLA on Mar 16, 2021 19:58:05 GMT
This is a separate room that I was hired to design and work on. (My other thread is the plans for my personal listening room.. sorry about that..)
The top of a grand piano will be about 4 feet away from the ceiling diffusers. The diffuser dimensions are taken from online calculators.. 20"w, 5"Dmax, 19 wells 1 inch wide. qty is 40
What about how near the piano is to the ceiling, if we're looking for reverb after 10ms. What Can I expect to measure and experience subjectively at this distance?
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Post by rock on Mar 16, 2021 23:43:57 GMT
What are the dims of the piano room and where will the piano go in it. Is this for just playing/practice or performance/recitals or recording?
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TLA
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Post by TLA on Mar 17, 2021 1:17:40 GMT
Practice and playing. The dims are 11'x15'
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Post by rock on Mar 17, 2021 3:50:44 GMT
Ok, thanks. So in my experience, the playing/practice room is almost exclusively subjective. I have been in hundreds or even thousands of rooms with pianos, mostly residential, and very few if any are ever acoustically treated. Even churches seem to often have minimal or random treatment. Theaters are the exception and of course recording studios are always acoustically treated.
In your piano room, it seems like you're going big on ceiling diffusion but the 1.2K to 8K seems to be on the high side of the spectrum but as I said, piano rooms are pretty subjective. But me personally, I'm used to listening in the horizontal plane and not so much from above as it can be sometimes distracting, so I don't know if I would go so big on ceiling diffusion and maybe balance it with some absorption but that's just me, it will probably be very interesting.
Having said all that, from the piano playing position, the room sound is secondary since you're so close the the instrument so too much absorption might not be the best idea... quite the opposite advice as for listening to recorded playback that has it's own ambience included.
Like I said, most all pianos I hear in homes are in untreated rooms and they exploit the qualities of the rooms they are in. Funny, but most of the owners just live with it and most actually sound subjectively OK. The real worst, IMHO, are the big rooms with 2 story heights which can be like being in a big cube...and to make matters worse, there is zero stuff on the walls in the 2nd story section...just dead air space.
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TLA
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Posts: 32
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Post by TLA on Mar 18, 2021 0:49:32 GMT
Thanks, great information! The room has absorption on the ceiling around the perimeter 2 feet wide.. The area inside the perimeter will have all diffusion. The frequency range for diffusion could be changed as I'll start building them in a few weeks.. Actually, I suggested to the owner of the home that alternating between absorbers and diffusers, but he liked the aesthetic of all diffusers.. The walls will be treated as well. I was planning broadband absorbers with about a 2 foot space between them..
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Post by Hexspa on Mar 18, 2021 10:56:44 GMT
From what I've seen in the Cox/D'Antonio book, rehearsal rooms had absorption at ear and instrument height and diffusion above that. Not sure whether the ceilings were diffuse or absorbent.
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TLA
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Post by TLA on Mar 18, 2021 12:19:50 GMT
I'm wondering if 1200-1400hz on ceiling is low enough for the amount of radiated energy from a grand piano?? Its the best I can do with the 4 inch depth depth that I have. The piano will have broadband around it on the walls, carpet on floor.. A few broadband panels hanging over the piano below the ceiling is possible.
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Post by rock on Mar 18, 2021 13:57:08 GMT
About the diffusor bandwidth of 1.2K to 8K, I first mentioned it might be a little high but you'll probably be OK. Here's a paper on piano acoustics. See the graph on page 33. www.jjburred.com/research/pdf/burred_acoustics_piano.pdfSome diffusion at ear level might not be objectionable. It sounds like you have flexibility with the wall absorbers so you might go at it incrementally and fine tune to taste. If all the panels are individual, modular and the same size, it should be easy to move them around for testing etc.
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Post by Hexspa on Mar 19, 2021 10:24:49 GMT
I can't speak on live and rehearsal rooms. For critical listening, I think just the bandwidth from 4-8kHz should be diffuse and decay extended. This is according to the Grammy P&E paper, IIRC. Reflectiveness is really a matter of taste. Technically, there's nothing wrong with a dead room for recording; at least that I'm aware.
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TLA
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Posts: 32
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Post by TLA on Mar 19, 2021 12:16:57 GMT
This will be the first time I've installed diffusion. I treated a different piano room(shown in my avatar) with extensive absorption. The pianist loved it.
For critical stereo listening, I know that I personally desire extensive absorption, my old room was heavily treated. The outdoor FR and CSD above 300hz@2M closely matched the measurements in the room. Under 300hZ it was well controlled as well, but of course not perfectly flat. Many People, including some that are well respected in audio science, Say I lot of absorption sounds terrible. Entering a treated room where human voices sound stuffy turns out to be great for stereo listening IME. "Reflectiveness is really a matter of taste" I think this finding is accurate for music and stereo listening, but not sure if article was only referring to Live and rehearsal.
Rock, the paper on piano acoustics is excellent. Thanks You!
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Post by rock on Mar 19, 2021 13:03:12 GMT
Yeah, once we get away from critical listening, mixing and translation between rooms for recording purposes, the parameters of an "ideal" room can get much more varied to the point where there is no such thing as "ideal". In addition, it's my opinion that the ear/brain has the ability to normalize the acoustics of any space we're in at the time and even the sound system. That probably explains why the "casual observer" rarely even notices the room acoustics and system quality we obsess over
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TLA
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Posts: 32
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Post by TLA on Aug 23, 2021 13:21:24 GMT
Here's 2 diffusers made from solid birch. I'm in the process of completing 42 units, all to fit between ceiling joists in the piano practice room. The wells required much experimentation for a nice fit. Turned out the best method for cutting strips was table saw with a glue line rip saw blade. All of the wood got 2 coats of spray finish before assembly.. Attachments:
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Post by rock on Aug 24, 2021 1:50:24 GMT
Wow, they look really nice!
Glue line rip blade? OK, I had to look that one up but yeah, that looks like it saves time and make a perfect cut!
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