Provided Link: http://www.woofertester.com
> Has anyone used the Woofer Tester 2 to tune
> a box?
Hi Ken,
There are two methods. The original WT2 method is to use the 'box test' button to find Ha, alpha, port tuning and a few other parameters like Qloss.
The other method is to compare a measured impedance curve with the simulator. What you will find is that by then adjusting the simulator box volume and tuning you can shift the simulated impedance peaks up/down as well as adjust the spacing of the peaks. The goal is to get both peaks to align in frequency. You can also adjust Qloss to make the peak heights line up better (btw, adjusting Qms has the same effect). The box volume and tuning from the simulator overlay should then be pretty close.
By the way, though the currently released WT2 simulator (ver 1.04) properly simulates the impedance effects of Rem/Xem, the acoustic effects will show up in the next SW release. In general this is not a problem unless you are dealing with a driver that has a particularly high value of Rem/Xem. Below are some links to pictures showing the simulated and measured response of an 18" that I have been playing around with that does have a large Rem/Xem effect. The box I made these measurements in is 10.5 cubic feet and is tuned to 19 Hz using two ports (this is still a little undersized IMO, but is as big as I am being allowed for now :-) The idea is to have a tunable system that goes well below 20 Hz with lots of output when I close one of the ports. At the moment both ports are open so tuning is high. Here are some links...
If you have more questions, email me directly
Comparison of measured and simulated impedance and phase
<A HREF="http://www.woofertester.com/cr18_zp.jpg">http://www.woofertester.com/cr18_zp.jpg</A>
Measured and simulated response including the effect of Rem/Xem (this will be a new feature)
<A HREF="http://www.woofertester.com/cr18_remxem.jpg">http://www.woofertester.com/cr18_remxem.jpg</A>
Measured and simulated response including the effect of Le (also a new feature)
<A HREF="http://www.woofertester.com/cr18_rle.jpg">http://www.woofertester.com/cr18_rle.jpg</A>
Theoretical output at 50 Vrms (300W->8 ohm) drive
<A HREF="http://www.woofertester.com/cr18_Xmm.jpg">http://www.woofertester.com/cr18_Xmm.jpg</A>
Best regards
Keith Larson "WT-Pro"
<A HREF="mailto:klarsondsp@comcast.net">klarsondsp@comcast.net</A>