DRL > Requests For Features

Better Sound Synthesis Technique

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thelaptop:

--- Quote from: Tavana on November 10, 2010, 23:53 ---I'm sorry, I just have to laugh whenever people use Wikipedia as their source.

That being said, I fully support a better sound management system.

--- End quote ---
* thelaptop shrugs
I'm at work... too lazy to look up the sources, so poor ol' Wikipedia will have to do.

Also, not an academic paper, so don't really care too much about where the sources are from.  =P

grommile:

--- Quote from: Tavana on November 10, 2010, 23:53 ---I'm sorry, I just have to laugh whenever people use Wikipedia as their source.
--- End quote ---
It's not the best source in the world, but given that the page in question does have citations, I think it's reasonable to use it as a source.

Captain Trek:
OK, well, in response to this little arguement, I've broken out my Year 12 Physics textbook from last year and there seems to be some confusion among you guys regarding the difference between sound intensity and sound level. The reson for this is that human hearing percieves sounds in a way that is rather mathematically odd, with an increase of ten times the intensity resulting in an increase in the sound level (percieved by the human ear) of 10 decibels, meaning a human doesn't hear the sound as being 10 times louder, even though it it is ten times more intense, which is due to the manner in which the human ear operates.

What is true, however, is that if you double the distance to the source of the sound, you quarter the intensity, rather than halving it (as it is indeed given by I = 1/r2). A doubling of sound intesnity will increase the sound level (in decibels) by about 3 dB, so if you double the distance (and thus quarter the intensity), the sound level will decrease by 6 dB... What the book doesn't seem to say, however, is how much quiter a decrease of 6 dB sounds to the human ear, though according to this website...

http://www.gcaudio.com/resources/howtos/loudness.html

...we percieve an increase of 10 dB (meaning an increase of ten times the intensity) as being roughly twice as loud and a 20 dB increase as four times as loud...

The bottom line here is that, laptop and thomas, neither of you is exactly right.

Laptop, it is indeed neccessary to put in ten times the power (as intensity is given by Watts per square metre) to make a sound the human ear will percieve as being ten times louder, but doubling the distance to the source of a sound will not make it sound twice as quiet (as the sound level will decrease by 6 dB every time the distance doubles, not 10), 'nor will doubling the distance halve the intensity (it will quarter it).

Thomas, your statement is correct with respect to sound intensity (how much actual power-per-unit-area there is), but as far as the human ear is concerned, standing 2 metres away from the source of the sound will not cause it to sound four times as loud than if you were standing 4 metres away (even though the intensity has indeed increased by 4 times, as you need the intensity to increase by 10 times to raise the level by 10 dB and thus make it sound twice as loud).

I hope that helps clear things up... I also hope I haven't gotten anything wrong here... :-/

Game Hunter:

--- Quote from: Captain Trek on November 28, 2010, 20:33 ---stuff about sound levels
--- End quote ---
Might be good to define some terms here:

Sound intensity is a measure of the amount of energy at the source of the sound. It drops off at a rate of 1/R^2.
Sound pressure is a measure of the amount of force coming from the source of the sound. It drops off at a rate of 1/R.
Sound level is a measure of loudness in proportion to the sound that is perceived. It is measured in decibels (dB) on a logarithmic scale (so that +10 dB = twice as loud, -10 dB = half as loud, etc).

Knowing this as well as how the ear detects (vibrations), we can determine that any sort of sound level is a result of the sound pressure rather than the intensity. The only real use of knowing the sound intensity is to determine how much energy is going into the source to produce a certain level of sound. For DoomRL, the only necessary component here is sound pressure. There is, however, a dampening effect through obstacles that should be factored into the equation.

As for the whole distance/level matter, you need to have a reference point (unless you want to get into figuring out the actual sound pressure at the source) before calculating anything. If we set our standard distance at 1m and measure the sound (I'll make it 50 dB, pretty average), then we get 40 dB at 2m away, 30 dB at 4m away, 20 dB at 8m away, and so on and so forth. This is the same as saying "it is half as loud at 2m away, a quarter as loud at 4m away," etc.

EDIT: If you need more clarification, I used this website to double-check some things.

thelaptop:
Well I did say that sound pressure is related to the loudness...

...and that the sound pressure is inversely proportion to the distance.  Intensity is not an issue because none of the stuff in DoomRL is supposed to yell so loud that it can shatter walls etc...

* thelaptop shrugs more
But Kornel needs to get this thing right, not us!  We just need to make sure that whatever voodoo he decides to use to get this thing going, it "sounds alright" with us.  =P

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