Bass traps? (to solve a suck out)


I have a terrible suck out at 61Hz. What should I do to address, I cannot move my subwoofer or room.
gchuva
A bass trap is a passive device that can only dissipate acoustic energy from a room. As such it can never eliminate a null in room response since it cannot add energy into the room. However, if you have two bass peaks it's possible that room traps can eliminate the peaks to generate smooth bass response. But in that case you didn't really have a bass null, but two bass peaks.

If you measure room response in narrow enough bands you'll typically find any number of very deep and very narrow nulls. As a practical matter they cannot be eliminated. Fortunately, they usually aren't a noticeable problem. Broad band nulls are a major problem. Repositioning the speaker and/or listener is the best way to address that type of problem.
Onhwy61 said "A bass trap is a passive device that can only dissipate acoustic energy from a room. As such it can never eliminate a null in room response since it cannot add energy into the room."

The energy is allready in the room (if your speakers/equipment are capable). The problem is a null is created when the waves come back to you and meet where you are positioned and those freq are cancelled and therefore not heard. Just the opposite of a peak where you are positioned at the peak of the waves coming together to reinfore that freq. A bass trap decreases the wave strength (reflection) and therefore decreases the null and at the same time brings down the peaks.

Onhwy61 said "But in that case you didn't really have a bass null, but two bass peaks."

So, have can you have peaks only and no nulls?

Bob
LOL. Bob is quite correct - bass traps can help suckouts. The others that chimed in against Bob are of course making what superficially appear to be logical statements. A very understandable misconception.

The same understandable thing happens when an audiophile attributes magical properties to a speaker cable when differences are mostly due to equipment design and matching (or slight change in seated position). Again superficially it seems like the cable is the only thing changed therefore it has "caused" all the change. Whereas poor equipment match and design or your head movement are the real culprits, as a cable should NOT cause dramatic changes if the equipment worked well together in the first place or you sat in the exact same spot with exact same volume levels.

Here is what Ethan has to say on Why we believe

and here is an article that suggests that bass traps can improve nulls and suckouts ...in fact this may be the biggest benefit of traps...it matches my limited experience with Ratschack meter and GIK Tri-traps - I trap mostly for nulls and use a PEQ (only on the sub) for taming peaks. It seems to work well and can probably fix almost any room - the key is to get rid of really bad suckouts and get reasonably flat - I would never recommend you go for ruler flat as I think the actual room sound is something to be enjoyed too, after all it is real and you can't hide it from your eyes and ears completely.

Of course, just two cents worth and I respect that often no agreement can ever be reached on these type of opposing views. For some, cables have had a huge impact and are clearly seen as having special properties and wires are worth treating cryogenically and all manner of other tweaks, such as raising them off the floor.