4
votes
Accepted
Are styrofoam skyline diffusers efficient as wood?
Diffusers are meant to reflect and scatter incoming sounds, not to absorb them.
Polystyrene is quite transparent to low frequencies, so the more rigid wood is the better material.
A more precise ...
4
votes
Accepted
What sound is best for measuring which frequencies a wall is reflecting?
If it helps, there are a couple of tools you can use to measure room acoustics. REW https://www.roomeqwizard.com/ and Sonarworks reference https://www.sonarworks.com/reference.
It's been quite a while ...
- 71
3
votes
best material to absorb Sound
Depending on how creative you want to get, the most effective sound absorption material I have found so far has been rockwool - which is the material often used for ceiling insulation. You can easily ...
- 8,815
3
votes
Accepted
How to interpret the analog output of an SPL meter?
Based on a suggestion by Jojek in a comment, I tested the DC output using a sinusoidal signal of stepped amplitude:
The results are given for 90dB SPL, 80dB SPL and 70dB SPL as read on the meter ...
- 197
3
votes
Accepted
Purely Mechanical Acoustic Frequency Converter
By far most passive acoustic systems are linear and time invariant. As such, they don't create frequencies not present in the original signal.
Passive systems that aren't linear are typically of the ...
- 46
3
votes
What would be the best "egg-carton" acoustic treatment method?
You need to ABSORB sound partly to reduce, and partly to keep it from bouncing around (which is why it sounds like a bathroom). So THICKER things like heavy curtains or moving blankets (or quilts) or ...
- 1,869
3
votes
Accepted
How does a cardboard paper towel roll amplify the sound?
Quite an interesting project indeed.
The paper towel roll and cups are are working as an acoustic megaphone, also called (in ancient times) speaking trumpet.
Directional focus of the radiating sound ...
- 721
3
votes
Accepted
What is the best shape for passive sound amplification
The best shape for high frequencies (and some high mid) is the horn. But a horn can actually take many shapes. For example, its walls can be parallel like a didgeridoo. In fact, most, if not all, wind ...
- 1,563
2
votes
Accepted
what is the purpose of the internal volume of a speaker cabinet
It's actually a complicated thing, how much space to put behind a driver. The air mass behind the driver actually affects how the driver moves. If you put the right volume of air behind the driver, ...
- 2,210
2
votes
Advice on calibrating complex stimuli that vary in amplitude and also decay over time
I don't know if there's an instrument that can measure this but you can calculate the RMS value of complex waveforms in many ways. It would include some maths so I would personally recommend using ...
- 1,563
2
votes
Do I really need to dump tons of sand into the stage i'm building?
I've worked in a few large stages (<5000) people and I have never seen a stage filled with sand. The stage is usually an aluminum construction made of lite decks or even steel decks. This is ...
- 1,563
2
votes
Accepted
Acoustics exercise
Sabin formula for Reverberation Time:
You know the target RT and the volume of the room. What you are looking for is the total absorption A, S is just a surface area. Technically, the unit of A is ...
- 299
2
votes
Effect of sound waves striking an object
Interesting topic!
If you first imagine that sound waves emanating from a point source (which you are going to have to approximate as a speaker) will emit spherically. Where the sphere intersects ...
- 8,815
2
votes
Accepted
Why not pointing the loudspeaker toward the sky during open-field frequency response measurement?
speakers don't just emit sound towards the front, they emit sound in 360 degrees despite the efforts of designers. Higher frequency drivers are more directional than lower frequency drivers. The lower ...
- 8,815
2
votes
Setting up Home Studio, need advise on setup
In a tiny room like that, with unspecified materials, the quickest way to find out is to try it.
My optimum in a home studio ended up being this…
My ceiling is also partially sloped. Room is approx ...
- 8,405
1
vote
Unknown polar pattern on MXL 990 mic
At this page you can find the microphones polar pattern and frequency response (the ones you provided), so you could have possibly found out before buying that the polar pattern is not a “perfect” ...
- 339
1
vote
Accepted
How to make realistic instrument sounds digitally from scratch?
It sounds like you're asking how synthesis works.
There are a few different types of synthesis. Historically, the earliest synthesisers did just use electronic components to create sounds. Later, ...
- 839
1
vote
How much should volume change for an empty room vs one full of bodies?
For a room that is already very absorbent simply adding people to the room is not going to make a noticeable difference. Consequently, you should balance the room like a normal mixing theatre would. ...
- 8,815
1
vote
Question about the Haas Effect
His wording is confusing, but he does mean that the two channels, the original and the duplicate, should be panned hard left and right. The whole point of using the Haas effect is to maintain the even ...
- 166
1
vote
Accepted
How does "transcribe!" or guitar tuner work?
Windowed FFT is indeed one of the usual approaches to find an approximation of a spectrum within every window - and there is a trade-off here, as wider windows mean worse time resolution, while more ...
- 125
1
vote
Accepted
"Super W" neoprene pads for electronic drum decoupling platform?
I would approach this from the perspective of having a rigid coupling between the seat, the drummer and the entire kit. Consequently, I think you would need a "floating" floor setup that can be ...
- 8,815
1
vote
Accepted
Shockwaves: loudness or speed?
Your research is heading in the right direction, but you should firstly understand that as an absolute measurement metric, the "decibel" is meaningless. It's like asking someone "how long is that ...
- 8,815
1
vote
Reducing Noise Levels in Dog Shelter Inexpensively
The floor mats you suggest are good, but based on an experience I had in a parking garage, I suggest that you also look into absorbent ceiling treatments similar to spray foam insulation. A sound ...
- 113
1
vote
Reducing Noise Levels in Dog Shelter Inexpensively
Moving blankets fixed to the upper walls and ceiling with industrial strength Velcro would do. Given it's a possibly dirty area you may want to be able to take these down and wash them, so might want ...
- 21
1
vote
Can I get a recommendation on how big and what type/brand of PA I need?
I would look for sound design companies or at least PA equipment vendors near you to give a recommendation; without being physically in the room it's impossible to give solid advice.
Even a couple ...
- 206
1
vote
How does a cardboard paper towel roll amplify the sound?
Pitch content that roughly matches the resonance tendencies of the shape will also get a boost relative to the other frequency content. The resonance frequencies of the tube are probably very limited, ...
- 316
1
vote
Designing a diffuser to direct reflections to side walls
A diffuser is used to scatter sound waves unevenly so the surface needs to be also very uneven. So you need a mildly reflective material such as wood or cork cut out so that it has edges and crevices ...
- 1,563
1
vote
Accepted
cancel out audio in a recording with convolution, phase inversion
...can I cancel out the sound produced by the speaker in the recording?
Theoretically, yes. In practice, mostly if you do a really good job, barely if you do a poor job.
You have the right idea with ...
- 341
1
vote
What would be the best "egg-carton" acoustic treatment method?
I covered my dorm room with egg cartons when I was in school. We used contact cement or a tough rubber cement (I think it was called "Goo") to stick them to the walls and ceiling. I agree with the ...
Only top scored, non community-wiki answers of a minimum length are eligible