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Can you correct nulls with acoustic treatments.

I have Magnepan 1.6's. After hearing a musical clarity I really liked in a listening session at someone else's house, I broke down and bought a Rat Shack SPL meter and dowloaded some test files. I wanted to see if it was the acoustics or the type of speakers and system that made the difference.

A brief testing showed a 65 to 80 hz., 5 or 6 db. bump (the drywall bump?) that I had expected. What I didn't expect was 10 to 15 hz. wide nulls (-10,-15,even -20 db.) at several other frequencies.

I tried moving speaker positioning and the frequency of the nulls moved but the pattern was basically the same.

Acoustic treatment to tame + nodes seems intuitive. Can you treat nulls or is this a different problem?

Would really appreciate your thoughts.

Jim S.

stilljd
rives
953 posts
 
Jim:

I like your attitude--and I think it's exactly right. You won't make that quantum leap overnight--but you can read, understand, try some things, and make progress over time. I wish everyone would deal with their room. Whether they hire a professional or take some sound advice (pun intended) and work through the issues themselves over time, the room is almost always the limiting factor in good sound.

I would recommend the book Alton Everest Master handbook of Acoustics. It's available through Amazon and is an excellent overview on the subject.
jlambrick
138 posts
 
I had a deep null in mid to low bass right where I wanted to sit. Then I noticed that the bass would almost blow your hair back in other parts of the room. I made a series of bass traps and I wouldn't have believed anything could be so effective. It's still slightly peaky at certain frequencies but not bad. I'll probably get a digital eq eventually.

BTW, my listening room (built before I moved into the house) is of horrendous dimensions. Very close to 1 x 2 x 4.
stilljd OP
163 posts
 
Per Shadornes' reco I purchased Rebecca Pidgeon, The Raven. Shadorne is absolutely correct. On "Spanish Harlem", the bass sequence cleary shows intensely audible bumps. Dumm, BOOM, BOOM, - BOOM, BOOM, Dumm, - BOOM, Dumm, Dumm. It is not subtle, nor musically pleasant.

I have heard the BOOM and new it existed in the setup. I use the bass boost from the room nodes to alter (amplify) the lower-mid bass for some of the music I like. But taken as a single note, it really sounds horrible, bloated, and out of place.

Very enlightening. The Raven is pretty good music too.

Best Regards,
Jim Still
shadorne's avatar
shadorne
7,491 posts
 
Stilljd,

I am glad this helped. It is an idea straight from recording engineer Bob Katz and his book on Mastering.

The single biggest benefit is that this track gives you a clear idea of just how room modes affect real music.
stilljd OP
163 posts
 
I have discovered a new way for the CIA/FBI/DOD to coerce information from suspects. Make tham listen to test tones all day! Doing room measurements manually with a CD and RS SPL meter is agonizing and time consuming.

Jim S.
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