Hi Plasnu,
Yes they does. Since antiquity it was used: i've visited an Orthodox church in Turkey which had a lot of different sized 'bottles' inserted into walls to correct some modes on the dome shaped room, and during same trip i've seen same things used on Greek amphitheater.
The issue with them is how they are implemented and the size needed ( at least with Helmotz).
Now they are not a panacea and can reveal other issues, being over or under done,... my experience with them is they can be a PITA (Helmotz). But maybe that's just my own failure and other have better results.
I experienced total failure with Helmotz resonators too. I suppose i messed with the build, based the calculation upon a non working calculator ( i've got a background in literary study, switched later to 'hard' science and so math is not my forte, so... i've got to rely on tools as i'm not able to do math by myself).
I didn't used the measuring technique at that time either. Since then i try to avoid them if possible ( the ratio time invested/cost/result was very low).
That said i've heard some implemented by pro which were effective. And it is easy to try as you just have to close the hole to switch them ( almost) off.
This isn't common on acoustic treatment and help to evaluate their efficiency.
I didn't used the measuring technique at that time either. Since then i try to avoid them if possible ( the ratio time invested/cost/result was very low).
That said i've heard some implemented by pro which were effective. And it is easy to try as you just have to close the hole to switch them ( almost) off.
This isn't common on acoustic treatment and help to evaluate their efficiency.
Hehe... my own failure, with measurements to back up:
https://gearspace.com/board/studio-building-acoustics/665657-diy-helmholtz-resonator-made-easy.html
https://gearspace.com/board/studio-building-acoustics/665657-diy-helmholtz-resonator-made-easy.html
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I remembered i've watched an Ethan Winer's video where he demonstrated the effect of his own products.
I couldn't find it till last evening.
It's interesting because it compare diffusors, absorbers, barewall and bookshelf in real life so gives an idea of what to expect* from such treatments.
* what is shown in this video is not what it bring to a playback room in my experience but it close enough to give you a feel of the 'character' of each demonstrated.
Some comments:
I've heard polycyndrical diffusors in three distinct facility and liked them. But the first room was a tracking/recording one and big. Such were some of the poly diffusors and they were located to limit the focusing aspect he speak of.
Both other rooms where control rooms and they were used on the backwall. In one case these were a lot of small one ( maybe 20 to 30cm) on the other two larger ones (something like 1m width by 2m height).
Both were effective and the larger one brought something with them when they were instaled ( i've been present at each step in this built). The lot of small one was into the A of sadly closed down +XXX Studio (+30) in Paris. This room sounded very nice and much bigger than it was ( despite being an already big room).
You can see them in this pic:
https://images.app.goo.gl/E4omiSn9DopsWAcX6
So they works, but not under the condition of the video.
Bookshelf example is not very fair in my opinion: the books arent 'organised' to help diffusion... if you want scattering to occur you need different 'well' depth so aligning books won't bring anything ( except maybe a bit of absorbing). But Mr Winer have to sell something...
That said, a bookshelf won't bring same thing as a dedicated diffusor: the dedicated ones have 'pattern' which are known, a bookshelf will be less predictable. This can or cannot be a good thing.
All recording are made fairly close to the difusors: player as well as recording mic. For the recording mic it is well into the zone where you can 'hear' the pattern of diffusion at work. It is usually considered than the diffusors must be used at a distance of at least 3x the wavelength of the lower effective frequency of the treatment ( defined by the 'well' depth). This this the rule of thumb used in control room.
The player/source being so close to the dif is not usual. It should play a role too and maybe exagerate some of the character of each treatments.
I couldn't find it till last evening.
It's interesting because it compare diffusors, absorbers, barewall and bookshelf in real life so gives an idea of what to expect* from such treatments.
* what is shown in this video is not what it bring to a playback room in my experience but it close enough to give you a feel of the 'character' of each demonstrated.
Some comments:
I've heard polycyndrical diffusors in three distinct facility and liked them. But the first room was a tracking/recording one and big. Such were some of the poly diffusors and they were located to limit the focusing aspect he speak of.
Both other rooms where control rooms and they were used on the backwall. In one case these were a lot of small one ( maybe 20 to 30cm) on the other two larger ones (something like 1m width by 2m height).
Both were effective and the larger one brought something with them when they were instaled ( i've been present at each step in this built). The lot of small one was into the A of sadly closed down +XXX Studio (+30) in Paris. This room sounded very nice and much bigger than it was ( despite being an already big room).
You can see them in this pic:
https://images.app.goo.gl/E4omiSn9DopsWAcX6
So they works, but not under the condition of the video.
Bookshelf example is not very fair in my opinion: the books arent 'organised' to help diffusion... if you want scattering to occur you need different 'well' depth so aligning books won't bring anything ( except maybe a bit of absorbing). But Mr Winer have to sell something...
That said, a bookshelf won't bring same thing as a dedicated diffusor: the dedicated ones have 'pattern' which are known, a bookshelf will be less predictable. This can or cannot be a good thing.
All recording are made fairly close to the difusors: player as well as recording mic. For the recording mic it is well into the zone where you can 'hear' the pattern of diffusion at work. It is usually considered than the diffusors must be used at a distance of at least 3x the wavelength of the lower effective frequency of the treatment ( defined by the 'well' depth). This this the rule of thumb used in control room.
The player/source being so close to the dif is not usual. It should play a role too and maybe exagerate some of the character of each treatments.
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