Acoustic response of your room

[axehead]

I'm currently just recording in my bedroom, but I was just wondering about acoustics, as my knowledge on this subject is almost non-existant. I was reading an SOS article about some guy's home studio. Here's an extract:

Another important design consideration was the acoustic response of the room. Once again, Russ was methodical in his planning. "I read in a Paul White article that a concave or arched space is the worst acoustic space you can get. I realised that was true when I bought the Genelecs, which are supposed to have really good stereo imaging. Even with them I didn't have a stereo image, because the sound bounced off everything. I could pan, but there'd be no noticeable difference at all!

"So I started experimenting with the lagging that you see on the walls. There's an upholsterers nearby that supplies a lot of material to hotels and hospitals, and they have a big odds-and-ends box. I bought masses of the stuff; 12 square yards for £10. I attached wooden batons to the ceiling and used a big staple gun to fix the lagging to them.

"The lagging worked, although the room has a bass hump at about 80Hz. Realising that, I bought a graphic EQ so I could filter that hump out. I've set the EQ so it dips at about 80Hz and comes back up at about 40Hz, although the monitors roll off about there anyway. Now the room response is quite flat, and considering its size and location it's not a bad recording space."

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I have a few questions from this:

1) How do you know when you've got lagging on the wall?
2) How do you know if you've got a bass hump?

Basically, how do I know what my room is doing to my recordings? How do I know if it has a flat response. I've heard people sayong things like, "I've got a bit of a bass hump patch to the left of my back wall" - how do they know this?

As you can see, I know nothing on this subject!

Thanks!

 

[Bushice]

Check out this thread. I just had this discussion, with the resident expert, John Sayers on this topic.

https://homerecording.com/bbs/showthread.php?s=&threadid=45394

It can be expensive to figure out the actual acoustic properties of a room, unless you have the equipment and the know how, however if you have room measurements, you can determine approximately where your problem areas are, and then pursue correcting them. There are several links in the thread I attached here that will help you get started. The SAECollege site is very informative, and should help you answer your questions.

Bushice

 

[Dan Merrill]

Lagging! Now there's a word for the homerec glossary!

Axehead, you know you've got lagging when you've put it up yourself, as in this case it seems the guy bolted some foam or thick fabric to the walls of his studio to reduce the wall reflections. As for bass hump- he's refering to an exagerated amount of certain frequencies in the low end.

To find out what your room "sounds" like- play a CD and listen to it from different areas in the room. Focus on the bass guitar, then the vocal, then the drum cymbals in each location. Some areas of the room may emphasize or exagerate the instruments differently. Corners may sound boomy with more bass sound- like the bass has actually been turned up. In the middle of the room you may hear some vocal or cymbal reflections/ flutter echo off the side walls or ceiling. All of these affect the definition and clarity of the music in the room, and if you are recording or mixing, the room's sound will influence how you will EQ and balance the tracks.

For example. If I shouted in a lockeroom shower my voice would sound quite echoey, as oposed to shouting in my coat closet, which would sound fairly natural. Truth is, the sound coming directly out of my mouth in both rooms is the same, yet the room themselves add their own sound to it. Get the idea?


As you start to hear these anomolies throughout your own room, you'll understand what it is we try to adjust, and why, with the many methods addressed on this BBS. Educating the ear is the first step...