Placing weight/mass on top of sub?

Medrep1

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Has anyone does this and noticed a shift in sound qaulity?

I'd be curious how this would improve/detract the bass performance of a sub?

I put my hands on the sub the other day whilst leaning over to the power sockets and noticed, what I percieved, as I tighter bass output?

Ive tried placing weights discs on top of the sub, 45kg in fact, with a tea towel between the disc and sub to protect, and the sub's vibrations pushed the weights off, 45kg!!! :eek: It puckered up the proverbial to say the least, I thought i'd knackered something:suicide:

Anyone experimented with such a thing, and measured with REW to see the difference in response?

Cheers.

Curious Cat?
 
Has anyone does this and noticed a shift in sound qaulity?

I'd be curious how this would improve/detract the bass performance of a sub?

I put my hands on the sub the other day whilst leaning over to the power sockets and noticed, what I percieved, as I tighter bass output?

Ive tried placing weights discs on top of the sub, 45kg in fact, with a tea towel between the disc and sub to protect, and the sub's vibrations pushed the weights off, 45kg!!! :eek: It puckered up the proverbial to say the least, I thought i'd knackered something:suicide:

Anyone experimented with such a thing, and measured with REW to see the difference in response?

Cheers.

Curious Cat?

Weighting speakers with ballast is a traditional way to improve bass response and focus as you probably know but it sounds like you could do with better isolation from the flooring. It the sub directly on carpet or bouncy floor boards?

There should be very little vibration on top of a decent well positiones sub, certainly not enough to rattle a 45Kg weight off the top, maybe get the wife to sit on it ;-)

Is it on spikes?
 
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maybe get the wife to sit on it ;-)

LOL!!:D

Now it sits on a very thick granite plinth, with high density foam underneath that.

When it shifted the weight beforehand, it was sat on the wooden floor, concrete foundation. There are x4 little rubber feet as standard underneath the sub, they were and still are remain in place.

I wouldnt try it now at risk of damage to sub or adjacent speakers etc.

Just curious what sonic advantages/disadvantages would be gained from such thing, as the sound surely does change?

Maybe I should run REW and experiment, carefully!!
 
When I made my first DIY sub I got a substantial measurable improvement by putting a heavy granite slab on it. So substantial that I assumed I must have changed something else without realising it...

This was a RELQ100e clone on a carpeted concrete floor (with spikes).

Dave
 
You're either using the driver to put energy into the air, or into the cabinet. The more inert you can make the box the better. Next time someone drives past in one of those little Citroens that tend to have more sub than engine just listen to how much noise the car makes as the panels and windows vibrate, your domestic sub's enclosure is doing the exact same thing, it's vibrating and humming in sympathy, all that noise from the cabinet is obviously going to colour the sound of the sub.
Ideally you'd make the box sufficiently dense and inert that it doesn't produce any significant output of it's own.
But then it would weigh a tonne and cost a fortune to make and ship.
Sticking the sub driver up in a small skip filled with damp sand would probably do the trick, probably a bit low on the WAF though!

Adding mass and damping the enclosure is an effective way of hearing more of the driver and less of the box.
 
I tried this with my little B&W sub and it definitely improved the 'punch' from it.

I never got the SPL out to test it though and I removed the weight because it looked pants.
 

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