tuning a box too low?

[jaygeorge1979]

i was considering the tangband neo 6.5" subwoofer to go with the mivi b3s project from zaphaudio.com....i found enclosure plans online with the box tuned to 36 Hz

The recommended freq range by the manufacturer is 35 Hz- whatever...point is, the 5.25" tangband neo sub freq range is more like 45 hz-1500 Hz...so my question is, what happens when you tune a sub box lower than the sub is designed to handle? for example, tuning a box to 35 Hz for a sub that the manufacturer suggests to keep between, say 45 Hz and 1500 Hz?

[Volenti]

There's nothing really "wrong" with tuning an enclosure below the Fs of the driver, it won't damage the driver (not directly anyway), it'll change the power handling profile, x-max vers frequency ect but that's par for the course.

The manufacturer's min-max frequency response is pretty arbitiary anyway, top end response will be limited by cone weight and voice coil impedance while lower end response can change dramatically with enclosure design and room gain. (I have a 12'' sub with a 42hz Fs in a 2.5m TL that has an in-room response that actually rises to just below 20hz, as an example of how the enclosure and room can affect these things)

[richie00boy]

Indeed, the manufacturers response at the low end is pretty much an arbitrary figure for a 'typical' box.

[jaygeorge1979]

so i guess it would be safe to toy with low tuning ported boxes without damaging the subs....this is what i wanted to hear

[BassAwdyO]

yeah you can tune a sub as low as you possibly want. When you get to infinite port length it wont exactly be a sealed box, but I bet the SPL measured would be pretty darn close.

Tuning too high for the bandwidth you're playing is what can be a problem. If you tune to 40hz say and give the sub 30hz content in the signal then it can easily cause overexcursion.

Just remember with smaller subs excursion runs out easier because displacment is what really matters.

Look for the vented alignment which offers flattest frequency response. Most transfer function gain for the particular bandwidth, and the highest power handling for the particular bandwidth.

[jaygeorge1979]

what is transfer function? why is high power handling needed?

also you said the excursion is important to consider also cuz this is what matters with small subs...how would you take it into account when building a box?

[richie00boy]

The box size and hence efficiency will determine thermal power handling, whereas excursion dictates SPL capabilities. Your best bet is to play about with some modelling software such as WinISD Pro and see how everything interacts.

[jaygeorge1979]

yea i am using winisd beta version...what does pro offer that beta does not?

[Rademakers]

A lot

Wkr Johan