I am a little confused about what box to build for my new woofer:
the 12" KW-120-THX Subwoofer
problem is when I plug it into a Linkwitz Transform spreadsheet from Trueaudio
http://www.trueaudio.com/downloads/linkxfrm.xls
it gives a 2ft^3 box response that goes only to 1 octave below the boxes resonance with a gain of ~10db. But this is the same response I could get from a similar sized ported enclosure! Is my math off?
the woofers specs:
Power handling: 500 watts RMS/1,000 watts max
VCdia: 3"
Le: 1.23 mH
Impedance: 8 ohms
Re: 5.79 ohms
Frequency response: 20-1,000 Hz
Fs: 28 Hz
SPL: 86 dB 1W/1m
Vas: 1.89 cu. ft.
Qms: 3.31
Qes: 0.42
Qts: 0.37
Xmax: 25 mm
38lbs
these were $200 at Partsexpress, but I think I got the last one, as I couldn't order 2...only one.
what would work best? I have a nice Yamaha P2500s (~700w RMS bridged mono 8 ohm) to power it.
the 12" KW-120-THX Subwoofer
An externally hosted image should be here but it was not working when we last tested it.
problem is when I plug it into a Linkwitz Transform spreadsheet from Trueaudio
http://www.trueaudio.com/downloads/linkxfrm.xls
it gives a 2ft^3 box response that goes only to 1 octave below the boxes resonance with a gain of ~10db. But this is the same response I could get from a similar sized ported enclosure! Is my math off?
the woofers specs:
Power handling: 500 watts RMS/1,000 watts max
VCdia: 3"
Le: 1.23 mH
Impedance: 8 ohms
Re: 5.79 ohms
Frequency response: 20-1,000 Hz
Fs: 28 Hz
SPL: 86 dB 1W/1m
Vas: 1.89 cu. ft.
Qms: 3.31
Qes: 0.42
Qts: 0.37
Xmax: 25 mm
38lbs
these were $200 at Partsexpress, but I think I got the last one, as I couldn't order 2...only one.
what would work best? I have a nice Yamaha P2500s (~700w RMS bridged mono 8 ohm) to power it.
Yes, your maths is off. Ported boxes (to be max.flat) need to be bigger than a sealed of Q=0.707.
ESP - The Linkwitz Transform Circuit
What were the values of closed box TS you used for the spread sheet?
The value of the LT is, it allows a much smaller box (Vb<<Vas) with a high Q, but you are using it in a box bigger than Vas. Most people that prefer closed box SQ over ported because with a gradual LF roll off, it is easier to integrate into smaller spaces w/o booming bass response. Note. LF extension is not always the final goal.
Build the small box (or simulate the model) and measure the resultant TS, calculate new values.
The value of the LT is, it allows a much smaller box (Vb<<Vas) with a high Q, but you are using it in a box bigger than Vas. Most people that prefer closed box SQ over ported because with a gradual LF roll off, it is easier to integrate into smaller spaces w/o booming bass response. Note. LF extension is not always the final goal.
Build the small box (or simulate the model) and measure the resultant TS, calculate new values.
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