Acoustic foam for echo absorbtion

SHL

SHL

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Looking for something to absorb echo in an open area/room. Anyone used or can recommend something like below?

hushecho.co.za

Wedge2.5 Acoustic Foam Black 30cm (24 Pack)

Shop the Wedge2.5 Acoustic Foam Black 30cm (24 Pack) from Hush Echo. View a wide range of acoustic foam and acoustic panel boards for all your sound absorption products
hushecho.co.za hushecho.co.za
 
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SHL said:
Home. Tiled area around 40sqm, will be used for teaching school kids.
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Rather do acoustic panels. You can even have the cover fabric printed with pictures. Make sure it's still a breathable fabric though. You might get away with a few cloud panels (suspended from the ceiling) and break up the walls with broadband panels. A wall mounted bookcase will also act as a diffuser in the space.

Basically, what you're aiming to do is to minimise the standing wave frequencies in the room (there are online calculators for these room modes), and reduce the early high frequency reflections. The panels will soak up all frequencies (if >50mm thick). The diffusion of the soundwaves will tighten up the clarity in the space.

Bedfoam, foam panels, egg boxes etc are garbage - they only deal with high frequencies, and poorly at best.
 
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SHL said:
Looking for something to absorb echo in an open area/room. Anyone used or can recommend something like below?

hushecho.co.za

Wedge2.5 Acoustic Foam Black 30cm (24 Pack)

Shop the Wedge2.5 Acoustic Foam Black 30cm (24 Pack) from Hush Echo. View a wide range of acoustic foam and acoustic panel boards for all your sound absorption products
hushecho.co.za hushecho.co.za
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Get them off TEMU. I got them at 400 bucks per 48-pack. Free shipping as well.

These will work fine for high frequency sound absorption. Just keep in mind you will need to cover a lot of surface area to get any benefit in a classroom environment. I'd say at least 40% of your wall area. And that includes the ceiling.

Reason being that there is not just one listening position so you need to cover every first reflection point for all listening positions. Which basically means you need to spread them out over the entire room rather than placing them in certain areas.
 
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The Darkness said:
Rather do acoustic panels. You can even have the cover fabric printed with pictures. Make sure it's still a breathable fabric though. You might get away with a few cloud panels (suspended from the ceiling) and break up the walls with broadband panels. A wall mounted bookcase will also act as a diffuser in the space.

Basically, what you're aiming to do is to minimise the standing wave frequencies in the room (there are online calculators for these room modes), and reduce the early high frequency reflections. The panels will soak up all frequencies (if >50mm thick). The diffusion of the soundwaves will tighten up the clarity in the space.

Bedfoam, foam panels, egg boxes etc are garbage - they only deal with high frequencies, and poorly at best.
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He's not building a studio. Standing waves occur with low bass frequencies. Those are not gonna be present in a classroom.

Those TEMU panels will do perfectly fine to eradicate high frequency reverb in a tiled room.

Buying expensive studio gear or even doing studio-level DIY for this application would be a total waste of time and money.
 
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agentrfr said:

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Again, overkill and a waste of time and money.

Bass frequencies are not an issue.

Those TEMU panels would still work out cheaper.

If you really wanna DIY then you can try find old curtains for free. The thicker the better. Hanging curtains along all 4 walls will definitely do the trick as well. Though you still need to sort out the ceiling.

Or if you wanna go really bergie you could even pin old clothes to the walls. Could look quite interesting... :ROFL:
 
The Darkness said:
You'd be better off building a few broadband absorption panels filled with Rockwool.
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Just an FYI for anyone wanting to build sound absorption panels for studio use (bass absorption).

Common 12kg/m3 pink fibreglass insulation is multiple times more effective than high density rockwool/fibreglass boards.

The thickness of the panel is the most important aspect that controls absorption. A high density panel is only more effective than a low density panel when it is also very thin, and as we know, the thinner the panel, the less effective it is overall.

Since we want a more effective panel overall we want a thicker panel, but when you increase the density of a panel beyond a certain point, it actually becomes less effective and starts reflecting sound rather than absorbing it.

Here we can see that a thick high density rockwool panel actually performs worse than a thick low density one:

1720605027315.png

1720605043237.png

And here is the pink insulation:

1720605072287.png

Comparison of 3 panels of similar weight using the 3 different materials:

1720605362939.png

As you can see, with an absorption coefficient at low frequencies up to something like 40 times higher than high density rockwool, the normal old pink fibreglass insulation from builders warehouse blows these high density panels out of the water.

You can also make a 300mm panel with a 100mm air gap and the results are almost identical to a 400mm panel, meaning you can make 3.3 standard size (1200mmx600mm) panels from one roll of 100mm thickness pink insulation.

1720605576356.png
 
tetrasect said:
He's not building a studio. Standing waves occur with low bass frequencies. Those are not gonna be present in a classroom.

Those TEMU panels will do perfectly fine to eradicate high frequency reverb in a tiled room.

Buying expensive studio gear or even doing studio-level DIY for this application would be a total waste of time and money.
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Standing waves occur at all frequencies. They are most problematic with lower ones. Since the fundamental frequency of a male voice is ±100Hz, it's very much worth dealing with. However, yes, OP is likely trying to reduce the HF early reflections and reduce the reverb time in the room overall, thus the sponge will likely be fine.
 
Very interesting thread, want to jump in as well. I have a two story house with an staircase that echos a lot of sound. Whether it is the soundbar/voices downstairs or steps when walking up.

Thought of getting some acoustic slat panels for the mid landing but they are so expensive. Second thought was getting acoustic panels from temu and perhaps do a shallow bookshelf.

Any other ideas, advice?
 
aquadat0r said:
Very interesting thread, want to jump in as well. I have a two story house with an staircase that echos a lot of sound. Whether it is the soundbar/voices downstairs or steps when walking up.

Thought of getting some acoustic slat panels for the mid landing but they are so expensive. Second thought was getting acoustic panels from temu and perhaps do a shallow bookshelf.

Any other ideas, advice?
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Carpets?
 
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