Dampen room resonant frequencies? How?

[rogue]

I'm in a slightly unfortunate situation where i've needed to squeeze my setup into a tiny space, and my oversized HS8's are now in the corners.

The problem is, every time i play a C#/Db on my guitar, bass or keyboard, the whole room resonates and shakes. It's rather unpleasant.

i guess this is a frequency of 554.37Hz with a wavelength of 62.23cm.

Is there a budget way (using quilts/pillows or something) that will enable me to target that particular frequency and dampen the resonances in the room?

I understand this is most probably much easier said than done.
[and hopefully nobody will suggest i need a thickness of exactly 62.23cm to pull it off]

[BertKoor]

554 Hz is pretty high for a room resonance.
Either you get 1/4th of that (138Hz) or some piece of furniture (or what's on it) is resonating.

Also happens at low volume?

[kingozrecords]

Put the chair you're sitting on on top of a quilt or thick carpet to avoid transferrance to the floor.
You could get a rubber mat like they use for weight lifting gyms.

There would be very little resulting impact from merely the wave through air.

[Unaspected]

554 Hz is pretty high for a room resonance.
Either you get 1/4th of that (138Hz) or some piece of furniture (or what's on it) is resonating.

Also happens at low volume?

It's also too high to be making the room shake: 554Hz is around the frequencies generated by a skateboard. So that has to be a harmonic, as you suggest.

Room corners are also a terrible location for monitor speakers.

[rogue]

Yep, 554Hz is too high. I just figured that's what caused it when i played a C# on my guitar or keyboard.

I have also realised that it only seems to happen when im sitting directly in front of my monitors.I took my bluetooth keyboard and wireless guitar and walked around the room. As soon as i stood up or walked away, that resonance was no longer as prevalent. It is horrid whilst sitting though and has put me off working on any music.

So i'm now thinking about trading in my Yamaha HS8's for some smaller 5-inch speakers.

I have some Presonus Eris 3.5's plugged into my (central) TV in the same room and they don't have this problem. So i'll need to check if they encounter the same problem if i replace the Yamahas with these.

And have already tried using the Room Control on the back and cutting the LF by -4dB.
Helps a tiny bit but not much.

[rogue]

So, the smaller Eris 3.5's have the same problem.

If i stick a sock in the rear reflex port it helps to diminish the resonance.

I'm wondering if speakers with a front-facing port might be beneficial.

Unfortunately, i live in a small apartment now, and don't have enough space to move things around.

[acYm]

look into diaphragmatic bass absorbers. you might need quite a lot.