From a Google search of images, I see there are rubber feet available for the end pin. Do you have that?

Maybe try setting it down on a large pencil eraser.

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(2B)+(2B)' ?

Purchase 4 pencil erasers and a concrete paving slab. Sit the slab on the erasers. Use that as your 'floor'.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

What is the frequency of the lowest note you play?

I'd be looking for "static deflection" of the paving slab on the rubber mounts to provide 99% efficiency for that lowest note
https://mason-ind.com/wp-content/uploads/2017/06/V...

I could not find an isolator efficiency chart in Hertz, so some cyperin' and figgerin' to convert cpm to Hz will be required.

At that point the sound waves may be exciting the floor and ceiling directly.

When young folks drive by with the sound systems in their cars on full thump some frequencies pass right thru our conventional 2X6 wood framed walls.

Does your neighbor allow trial-error solutions or experimentation?
Is the structural vibration path dominant over the acoustical/airborne path?
Can you relocate your instrument position relative to floor construction (joists)? Sometimes a few inches can make a difference or move closer to a support wall.
Be aware that vibration isolation can change the instrument sound for better or worse, change elevation of instrument, and change lateral stability of instrument.

If you want to try a low cost approach without engineering, then here a few products:
Sorbothane Material for vibration isolation and damping

https://www.amazon.com/s?k=sorbothane+feet&i=e...

Isolate It: Sorbothane Vibration Isolation Circular Disc Pad .5" (1.27cm) Thick x 3" (7.62cm) Dia. 30 Duro - 4 Pack
$53.00
From <https://www.amazon.com/Isolate-Sorbothane-Vibratio...;

Isolate It!: Sorbothane Vibration Isolation Circular Disc Pad .5" Thick x 2.25" Dia. 30 Duro - 4 Pack
$26.00
From <https://www.amazon.com/Isolate-Sorbothane-Vibratio...;

SVS SoundPath Subwoofer Isolation System, 4-Pack
$50.00
From <https://www.amazon.com/dp/B00NCSQ5GK/ref=sspa_dk_d...;

The basic concept for vibration isolation is to have the lowest possible natural frequency that is well below the frequency that is being isolated. If the lowest instrument frequency is a C-note at 130-Hertz, then the bass instrument sitting on the isolation device should have a natural frequency of about 13-Hertz or lower.

Walt

@Tmoose & @Strong Thank you for the questions and suggestions, I'll look in to Sorbothane pads. They appear superior to pencil erasers.

My lowest note, E, is 41Hz.
Fundamentals Harmonics To
4-string Bass 41Hz-392Hz ~4kHz-5kHz

- Does your neighbor allow trial-error solutions or experimentation?
Yes, he can't stop me.
- Is the structural vibration path dominant over the acoustical/airborne path?
Structural for downstairs neighbor.
- Can you relocate your instrument position relative to floor construction (joists)? Sometimes a few inches can make a difference or move closer to a support wall.
Yes.

Question
- Besides moving close to a support wall, what other placement tips do you suggest? Between beams or directly on one?

The concrete slab is crucial.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

What is the weight (lbs.) of your instrument?
What is largest diameter of the end pin?
How much higher than your playing position (standing or sitting) can the instrument be raised off the floor?

Answer to your last question: place directly over floor joist or preferably over vertical support column to minimize exciting floor vibration modes.

Is your apartment in a wood structure, concrete or other construction?

Walt