Sound and vibration control


As an engineer, I wanted to share the results of an experiment I just ran. I have two SVS PB16 ultra subs and my wife got me the SVS isolation rubber feet for Christmas. We have an old house with hard wood floors and when these subs really hit, it does shake these floors. My Focal 1038BE speakers only have spikes for feet, and not so good on old hard wood floors. So, just bored and foing around, I mounted these isolation feet on my speakers, reset them and started playing music.
I was expecting nothing, and was pleasantly surprised to find the base tighten up and midrange actually improved.
I understand physics and this makes no sense. Most of the energy is still being created by the same drivers. Decoupling the speaker from the wood floor with rubber feet should not improve midrange.
Is this some type of “I’m an old man and losing it”, or might there be something to this?
Any one else out there ever try something like this?
Thanks.
128x128sonyesman2
Perhaps the improvement in the bass opened up the midrange by reducing phase cancellations. I too added these feet to my two SVS SB2000 subs and the improvement in clarity of the bass was noticeable.
Hi sonyesman
I don't have any idea why. But different feet will make the speaker sound slightly different to me. Good speaker companies will be a little particular about the feet they put with their speakers. But it is fun experimenting like you have when there is no cost or little cost involved. I probably change things around a couple times a month until I settle on something that I am happy with. After that I don't really care if something else is much better, I just enjoy what I have going on and don't worry about chasing the next big thing. Your having a knowledge of physics I probably haven't provided any helpful information. Sorry.
That's why survey courses are often repeated in both Fall and Spring semesters.
My theory is that changing the vibration/resonance with various feet and platforms will result in a change in sound.The floor would resonate at a different frequency.
Mass-on-Spring systems like the ones we’re discussing here, where the speakers provide the mass, behave like mechanical low pass filters, thus preventing almost all speaker cabinet resonances from reaching the floor, since the resonant frequency of the iso system is well below the lowest frequency produced by the speaker, thereby greatly reducing mechanical feedback to the electronics. The effectiveness of isolation would be very close to 100% for frequencies above 30 Hz. One thing the speaker isolation system won’t do is prevent speaker vibration from affecting the internal crossover and wiring.