stuffing for sealed cabs

[slr 5000]

hi all
lets say i needed a cab of 131 litres sealed for a q of .707
un stuffed (0 fill)

how much could i reduce the cab volume using 100% fill (stuffing)
and remain at the same q .707

is there an approx formula like say for 100% fill you can reduce the cab volume by say 10% as opposed to 0 fill

[Iain McNeill]

That's the number I've seen banded around (10%)

There's a lot of variables like how much you stuff and the density of the fibre. Then again, calculating the internal volume is non-trivial unless you have 3D modeling SW.

If you need to make the cabinets small then by all means take a full 10%, the error in Qts won't be audibly huge and can easily be corrected with a simple filter.

If you have leeway in size then design for no stuffing, add stuffing, test, then remove excess volume by glueing in blocks of wood until Qts is where you want it.

There's lot's of ways to skin a cat

[slr 5000]

thankyou ian
i was thinking the same

regards sheafer

[Dr. Ram]

Originally posted by slr 5000
hi all
lets say i needed a cab of 131 litres sealed for a q of .707
un stuffed (0 fill)

how much could i reduce the cab volume using 100% fill (stuffing)
and remain at the same q .707

is there an approx formula like say for 100% fill you can reduce the cab volume by say 10% as opposed to 0 fill

Yes there are published formulas. The exact results tend to depend on the other driver parameters too - such as Qts and Fs, but the formulas predict that if your unstuffed sealed volume is 131 litres, you can actually reduce the enclosure by about 40% to retain the Q at .707

-Ram

[planet10]

Sealed boxes are quite forgiving. Sources cite theorecticaaly as much as 30% but 20% is probably the practical limit. Also dependent on the kind of damping. As well too much damping will tend to strangle the sonics. The 10% figure is probably a good one to work with.

dave

[infinia]

You could use added series resistance to get another 10-15% and along with stuffing for 20- 30% total volume reduction.

Unibox freeware can model these two sources.

Ultimately it is easy to measure and adjust the amount of added/ing damping for your final Q, also the measurement will validate your Unibox model.

[slr 5000]

thanks guys you are great
the reason i ask this question is im doing a manger zero box 103 clone
but using scanspeak 25w/8565-01 instead of the 10" vifa drivers that manger is using

after playing around with lspcad ive worked out that for 2x the above drivers per cab i need 131 litres for a q of .707

after playing around with some measurments the above volume will not let me mimic the original box size of the zerobox 103 manger close enough( it will be heaps bigger and not look right) but if i could somehow get the box volume down to around 100 litres whilst keeping the .707q i could get the cabs almost an identical size to the zerobox 103 which is what im after
an exact clone in size ,looks and dimension but with the scanspeak drivers instead of the vifas

regards sheafer