Would adding some acoustic wadding to the inside of a ported subwoofer make any difference to the sound?
How would it affect it?
Thanks
How would it affect it?
Thanks
hi Howard, usually ported subs don't benefit from stuffing nor, is it needed due to such a low crossover point. from what i've heard, good bracing is important though especially, on large enclosures.Howard said:
😉
Stuffing damps resonance, this is not always easily heard but it's effect is easy to measure (drivers impedance at resonance is reduced (damped)).
Since a vented enclosure more or less works by resonance stuffing it will reduce output, this can be helpfull if the tuning is too high and it has a peaky/boomy sound but is otherwise detrimental to performance.
ie; if it sounds bad try stuffing it, it's an easily reversable tweek.
Since a vented enclosure more or less works by resonance stuffing it will reduce output, this can be helpfull if the tuning is too high and it has a peaky/boomy sound but is otherwise detrimental to performance.
ie; if it sounds bad try stuffing it, it's an easily reversable tweek.
What about in a full-range ported cabinet? The cabinets I'm building are 100 litres, and I'm going to control panel resonance with plasterboard and much bracing, should I also be using wadding and if so how much and where?
Crossover is 1kHz and th edrivers are Tannoy 12" HPDs.
Crossover is 1kHz and th edrivers are Tannoy 12" HPDs.
I'd line the walls with about 1'' thick sheet wadding and double or triple up the thickness directly behind the driver, massively complex bracing can also have a damping effect and help to break up standing waves also.
Stuffing a ported subwoofer will lower the tuning point because the box will be acoustically bigger. You could cut the pipe a bit shorter to counteract this.
Damping in ported subs
I use damping in ported subs, only where I need to control standing waves.
Usually the problem is the longest dimension on a tall box, so I use foam sheet on the top and bottom surfaces, which are zones of high pressure. For a deep box, I line the back panel as well.
Note that since the velocity at a wall boundary is zero, there is no advantage in using acoustic wool on the walls
The centre of the cabinet is a zone of high velocity, so I make sure I design in a shelf brace which has acoustic wool stapled across the cutouts.
I also ensure that the wool is not between the port intake and the driver - I don't want to lose any energy from the port. 😉
regards
Collo
I use damping in ported subs, only where I need to control standing waves.
Usually the problem is the longest dimension on a tall box, so I use foam sheet on the top and bottom surfaces, which are zones of high pressure. For a deep box, I line the back panel as well.
Note that since the velocity at a wall boundary is zero, there is no advantage in using acoustic wool on the walls
The centre of the cabinet is a zone of high velocity, so I make sure I design in a shelf brace which has acoustic wool stapled across the cutouts.
I also ensure that the wool is not between the port intake and the driver - I don't want to lose any energy from the port. 😉
regards
Collo
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