Room acoustic

[cominup]

Dear all,


Now, I get a room (WxLxH) (3.1x3.5x3)m or (10.33x11.65x9.84)ft. It's so hard to listen to in this room.

Do u hav any suggestion of room acoustic? And I hav not found out some where in our 4rum talking about this matter. Do u know where it is?

Thanks

Cominup

[Geek]

Hello,

Hard to listen.... why?

Too boomy? Too flat?

[Tenson]

Since this is the loudspeaker forum I would make the suggestion that you choose a speaker which will work well in that room. An open-baffle maybe? Placed close to corners they will not excite room modes as much as a box speaker. You do need to control the midrange and high frequency reflections though.

[nunayafb]

cominup, I am in a similar situation although my room is a tad wider and longer. the speakers im building to deal with this room are both waveguided(front and rear) and dipole. the benefit to waveguiding is to "focus" the sound more forward and less sideways and dipole systems tend to have a null or a quiet spot 90 degrees off axis which minimizes room modes. This is a fairly difficult project though and i dont know where you are at in terms of knowledge and skill. Anyways the point of all that was to illustrate that different speaker types are beneficial in certaing listening environments.

To answer the question you asked, try searching for:
room treatments
bass traps
room acoustics
room reflections
those keywords will bring up enough articles to get you started and enable you to ask more specific questions to achieve your goal.

Also, tell us a little more about your speakers, music type, movies?, do you have issues with neighbors/family/roommates who would prefer not to hear your music? Do you have Eq, what kind of amps etc...

[Dr.Faustus]

Ouch!

Your room is very close to square, which makes for difficult or poor acoustics (as you already know). Those nearly square dimensions mean that the room modes (natural resonant frequencies determined by the distance between opposite walls) for width, length and height are very close together. When you have multiple room modes that are very close to one another you will get exaggerated peaks and dips in the room's frequency response.

The simplest answer is to pick a different room with room dimensions (h*w*l) that are not similar or multiples of each other.

If you can't use another room, that's when you need to start looking into modifying the room to improve its acoustics. Start with a room acoustics calculator like this one: http://www.ultimateavmag.com/news/10388/

According to this calculator the problem frequencies for your room are: 57.4, 114.7, 172.1, 229.4, 286.8 and 290.7 Hz.
I expect that you have a BIG problem around 290 Hz as two of the "problem frequencies" are within 4Hz of each other.

The next task is to buy the "Master Handbook of Acoustics" by F. Alton Everest. This is an invaluable resource that is filled with useful information. I suggest that you buy the Master Handbook of Acoustics as it is a necessary resource and you will often want to re-read sections.

Here is a page with a few more links to get you started: http://www.epanorama.net/links/audioacoustics.html This will get you started, as room acoustics is a large subject. You have a lot of reading to do!

Please know that for almost every commercial acoustic treatment product that is sold, there is a DIY solution that will be as effective and often for much less money.

FWIW,
Dr.Faustus

[F1 FAN]

Hi you might find some helpful info here. http://www.avsforum.com/avs-vb/showt...2&page=3&pp=30 and here http://www.audioasylum.com/forums/rives/bbs.html

[cominup]

Thank you all,

Shareing with your hobby, I really wanna building up a place to make a open environment in a limited room.

Now, I'm using a pair of JBL LE14A and Altec 811 horn and 802 driver. CDP: TEAC 10SE and powered by some different kind of tube amp. I often listen to Jazz, Blue, Classic and sometimes The Door, Led Zeppline or Jimmy Hendrix. So, I can not have any sound of music in this room.

This one just be used for listening only, so, I can not change and no-one can disturb me.

Yes, I'm thinking about bass traps, diffuser, absorber... But, one thing is WHAT the rate to mix them together and HOW to make them like room decoration.

But, first of all, build a acoustic room is goal rite now.

Once again, thank you very much for all your information and link.

[MBK]

You might want to read this article on loudspeaker positioning and room acoustics . In brief, you do want some room effects, because they are necessary for realistic sound in the bass. Square dimensions are worst though. Possible solution is asymmetric placement, if the dimensions cannot be changed. All this applies even without room treatments. And
this article here is specifically on loudspeakers in small rooms.
Best of luck!

[ralphs99]

I can agree that both the articles suggested by MBK are essential reading.

It's worth going through all of Floyd Tooles articles on room acoustic in detail. There's a wealth of information, and they're available for free on Harman's web site.

David Griesinger's articles are also invaluable, not only those dealing with loudspeakers, but also his series on psycho-acoustics and recording techniques.

I have also put together a summary of some of the ideas of these authors and some easy to read general information on room acoustics on my new web site. http://www.aeronet.com.au/Acoustics.htm

Cheers, Ralph

[cominup]

Dear all,

Hereafter is a very cool site, isnt it?

http://www.mhsoft.nl/Helmholtzabsorber.asp