But does it resonate? (the furniture)

[alaios]

Hi all,
last week I did the blasphemy to put a tiny sub (6 1/2 inches woofer) atop of a furniture. This is not any normal furniture. It has been built to be very sturdy based on this guide

The Cabinet & the Subwoofer

I’m in the interesting position of telling you how to do something with a subwoofer that you shouldn’t do. No, it’s not illegal. But in the ears of those for whom sound quality is more important than ergonomics, décor, and/or domestic tranquility, it’s definitely heretical. So let me say at the...

www.soundandvision.com

and also it isscrewed to the wall.
We have also used a vibrometer and we almost got not any vibrations when we have been hitting the surface. A big table was way too more shaky when tested with vibrometer.

Still I want to learn what is the type of measurement that can check that there is any resonance from that surface. I am sure that people have tried to measureme similar things from wooden floors, thin walls etc. Can you give me such a guide that I can follow?
Regards,
Alex

 

[HarmonicTHD]

Hi all,
last week I did the blasphemy to put a tiny sub (6 1/2 inches woofer) atop of a furniture. This is not any normal furniture. It has been built to be very sturdy based on this guide

The Cabinet & the Subwoofer

I’m in the interesting position of telling you how to do something with a subwoofer that you shouldn’t do. No, it’s not illegal. But in the ears of those for whom sound quality is more important than ergonomics, décor, and/or domestic tranquility, it’s definitely heretical. So let me say at the...

www.soundandvision.com

and also it isscrewed to the wall.
We have also used a vibrometer and we almost got not any vibrations when we have been hitting the surface. A big table was way too more shaky when tested with vibrometer.

Still I want to learn what is the type of measurement that can check that there is any resonance from that surface. I am sure that people have tried to measureme similar things from wooden floors, thin walls etc. Can you give me such a guide that I can follow?
Regards,
Alex

The free REW software in connection with a ca 80USD UMIK 1 measurement mic will allow you to do a frequency sweep eg 20 to 20kHz. The result will show you possible resonances either caused by the room or by the furniture therein.

I have an old antique cabinet which resonates at ca 30Hz and the speakers aren’t even placed near it. REW shows it quite clearly.

 

[Keith_W]

What about the old fashioned way - place a glass of water on top of the surface and look for ripples?

 

[alaios]

The free REW software in connection with a ca 80USD UMIK 1 measurement mic will allow you to do a frequency sweep eg 20 to 20kHz. The result will show you possible resonances either caused by the room or by the furniture therein.

I have an old antique cabinet which resonates at ca 30Hz and the speakers aren’t even placed near it. REW shows it quite clearly.

which is the measurement we are talking about? Can you post an example on how it looks like?

 

[alaios]

What about the old fashioned way - place a glass of water on top of the surface and look for ripples?

that is a nice tip indeed

 

[restorer-john]

What about the old fashioned way - place a glass of water on top of the surface and look for ripples?

What about a glass of beer? It's a better indicator. Wait for the telltale ripples and reward yourself for being so clever in 'locating' the resonance by drinking it. Then, pour another and look for some more 'resonances'...

 

[tuga]

The free REW software in connection with a ca 80USD UMIK 1 measurement mic will allow you to do a frequency sweep eg 20 to 20kHz. The result will show you possible resonances either caused by the room or by the furniture therein.

I have an old antique cabinet which resonates at ca 30Hz and the speakers aren’t even placed near it. REW shows it quite clearly.

How can you tell?

 

[restorer-john]

How can you tell?

Because he pressed on a few panels and the resonance peak disappeared?

I've had purpose built HiFi cabinets where the resonances in the long panels were audible, so much so, I gave up and sold the cabinets.

(9ft long, 3 drawer, flat top surfaces and light weight rear panels- all too hard and too annoying to fix) Nobody's fault- you live and you learn.

 

[HarmonicTHD]

How can you tell?

… as John said, also moved it out and compared FRs etc. No REW does not tell you which furniture resonates

 

[Keith_W]

Since I got my new subwoofers, the whole house resonates. I went through this exercise of using REW's sine wave generator to produce a steady tone, then went around the room pressing on doors, windows, furniture, picture frames trying to locate what was vibrating. I stuck felt pads under picture frames and in door jambs, leaned heavy objects against windows, and did everything I could. In the end I suspected that the walls were resonating (my house is typical cheap Australian brick veneer on wooden frame construction), so I simply cut the frequencies below 30Hz using Acourate. I hope the OP does not have to resort to the same solution.

 

[alaios]

What about the old fashioned way - place a glass of water on top of the surface and look for ripples?

If this was not a joke I did the experiment. I picked a lightweight plastic jar which I think is way less stable than a glass of water

I played the it is my life way louder of I typically listen and I made a video. Let me know if you spot something

VID_20230320_082740.mp4

drive.google.com

 

[dasdoing]

If this was not a joke I did the experiment. I picked a lightweight plastic jar which I think is way less stable than a glass of water

I played the it is my life way louder of I typically listen and I made a video. Let me know if you spot something

VID_20230320_082740.mp4

drive.google.com

run a slow sweep

 

[3125b]

Online Tone Generator - generate pure tones of any frequency

www.szynalski.com

Careful, start at low volume.

You'll probably be able to hear some obvious resonances, my rooms door for example resonates at 31Hz.

 

[fpitas]

What about a glass of beer? It's a better indicator. Wait for the telltale ripples and reward yourself for being so clever in 'locating' the resonance by drinking it. Then, pour another and look for some more 'resonances'...

Doesn't that method require putting shrimp on the barbie?

 

[alaios]

Online Tone Generator - generate pure tones of any frequency

www.szynalski.com

Careful, start at low volume.

You'll probably be able to hear some obvious resonances, my rooms door for example resonates at 31Hz.

how do I feed that into my system though? And what did you do with your doors?
So we do not get anything from the water test I did?