Clap test

[damonrpayne]

What is the significance, if there is any, of what you hear when you walk around clapping loudly in your room.

In a somewhat spartan room, like my spare bedroom I can clap and hear a momentary echo, no big deal. I had never thought of this before, but I walked around my movie room doing this. In the front of my room, I was actually shocked at the echo-sound that clapping produces. I'm not very good at describing sounds but it sounds more like dropping a phone book in an empty garage than clapping in a room. boing-oing-oing-oing-oign-oing, and keeps up for slightly more than a second. I was thinking that part of this could be the hvac duct on the ceiling that is somewhat near the front of the room. I should really record this sound and post it here, I'm sure this must be affecting what I hear from the speakers.

[DrWho]

What you're hearing is due to parallel solid bare walls. Why can't I remember the name for this echo??? Bah, so stupid as it's such a common term.

Anyways, that boinging is why I was recommending you splay your side walls. You can fix it with acoustical treatment, but it's going to require covering a lot of the surface of the wall with diffusors. You might also consider absorption in places where you can't redirect the reflections away from the listening positions.

You aren't going to notice it as much at the listening position because the furniture is breaking up the standing waves.

[WMcD]

I've always called that a slap echo. In my view it demonstrates a poor acoustic condition but I'm sure others will join in to say the acoustic condition has to be measured.

Of course the echo is a time domain effect.

Gil

[mas]

ssd

[damonrpayne]

What you're hearing is due to parallel solid bare walls. Why can't I remember the name for this echo??? Bah, so stupid as it's such a common term.

Anyways, that boinging is why I was recommending you splay your side walls. You can fix it with acoustical treatment, but it's going to require covering a lot of the surface of the wall with diffusors. You might also consider absorption in places where you can't redirect the reflections away from the listening positions.

You aren't going to notice it as much at the listening position because the furniture is breaking up the standing waves.

Yeah, the room turned out pretty decent, so I still don't think I regret building in normal-style. All I want for xmas is a bunch of rpg panels;)

[DrWho]

Thanks Mark, flutter is what I was thinking of.

I associate slapback with a distinct reflection arriving late enough that it is perceived as its own reflection (I guess that means a single reflection happening outside the Haas Window). This would be akin to the refleciton you get off a building behind the audience at an outdoor show...a different kind of annoying.

So Damon...is your wife on MSN or anything like that? We'll all pitch in and send her flowers and stuff all through the year and you can take credit for it and then we'll drop the hint that you want acoustical treatment for xmas.... []

[damonrpayne]

She is on MSN! She has nearly zero to do with the finances though. Since I am getting a new pre/pro next week I'll hold off on budgeting $2000-ish for RPG products and $149 for more software until there's snow on the ground...

Too bad you're not around for my new listening test DrWho. Can boomac, j-malotky, RFinco, and my wife tell the difference between DVD-calibur DTS at 1.5mb/s and uncompressed PCM at 10mb/s and up? {Queue maniacal comic book music}

[Groomlakearea51]

Quoting MAS: Thus, from there, the steps are reducible to addressing sanding waves with bass traps, defining the initialing signal delay gap whereby forst order reflections are surgically damped creating an early response zone that is essentially anechoic for the direct signal, and then diffusing the remaining environment consisting of later arriving specular reflections sufficient to create a well-behaved exponentially decaying semi-reverberant space with regards to gain versus time.

Simple Rules:

(1) Find the standing waves; they are in the corners to start with.

(2) Absorb the "bad reflections"

(3) Diffuse the rest

(4) Measure with your ears and with test equipment. Always trust your ears!!!

MAS: Comments on this? I think this is what we determined when condensing it all down to a simple instruction set, in some logical order?

[colterphoto1]

What I hear in a drywalled room is the 'ping' from a plethora of similarly shaped (94x14.5 inch) rectangles of membrane, all vibrating at the same frequency. Drives me nuts. My house has plaster walls 1" thick. I've always thought that some form of blocking behind the walls at random intervals would help in this regard.

[DrWho]

You've also got those firewalls midway between the walls providing that extra support...

I think there is something to the vibrations of the walls that isn't really being stressed in all the acoustics literature that I've come across. There is definitely a signature sound to the various materials and thicknesses.

Though I do recall reading that Teac supposedly sounds really cool and is the reason why it was used in the Foellinger Great Hall inside the Krannert Center...supposed to be one of the best sounding Halls in the world and it's right here on campus [H]

[dkp]

What you're hearing is due to parallel solid bare walls. Why can't I remember the name for this echo??? Bah, so stupid as it's such a common term.

Anyways, that boinging is why I was recommending you splay your side walls. You can fix it with acoustical treatment, but it's going to require covering a lot of the surface of the wall with diffusors. You might also consider absorption in places where you can't redirect the reflections away from the listening positions.

You aren't going to notice it as much at the listening position because the furniture is breaking up the standing waves.

Doc-you gotta quit using these technical terms. It can get prettty confusing sometimes, ok? [][]

BTW-I've got a present for ya' when I see you again... lol

-David

[mas]

fee

[DrWho]

I post while I'm in the lab or in meetings or at work - right now I'm

at work AND doing homework. Anyone got any experience with hardware

interfacing with NAND Flash memory? It's sooooo exciting! [:@] (where's

the *bang head on wall* animation?)

Since this is way easier than trying to figure out standards, I'd say the wall

cavity is behaving like both [] I think it's really just a matter of

perspective and the context of the situation. But I agree, it would be

terribly easy to measure. After that, it should be rather trivial to

apply to the design of any acoustical space.

[damonrpayne]

I software interface with memory all the time...

[mas]

I software interface with memory all the time...

Many of us should, but I fear few of us do!

Oh, but you are talking about computer software and not skulls full of mush.... [][][]

[oldtimer]

Where's Jackson Bart when the subject is "clap test?"

[mas]

Where's Jackson Bart when the subject is "clap test?"

...........Being tested? []

[michael hurd]

Does it hurt to pee? [:|]

[mas]

Does it hurt to pee? [:|]

...only if an impulse stimulus is applied inappropriately...[]

[boomac]

Did you put the two panels up Damon?