I just did a quick measurement on the woofers on an open baffle and the measurement result was weird, in particular I am looking a the frequency curve. It had typical roll off starting from 30hz then from 30hz it was flat till 5k with a massive dip around 3k.
I placed the mic about 2cm from the centre of the woofer. Even if it is not the most accurate measurement, the frequency curve should be a little different as the specs according to the website linked is up to 2k.
Any ideas? Has is something to do with the open baffle?
I placed the mic about 2cm from the centre of the woofer. Even if it is not the most accurate measurement, the frequency curve should be a little different as the specs according to the website linked is up to 2k.
Any ideas? Has is something to do with the open baffle?
Open baffles cause such dips in response. I attach an illustration from the link I gave you previously.
The location and severity of such dips will depend on the size and shape of your baffle as well as the positioning of the driver on the baffle.
I still think that aperiodic loading would suit your drivers best.
The location and severity of such dips will depend on the size and shape of your baffle as well as the positioning of the driver on the baffle.
I still think that aperiodic loading would suit your drivers best.
Attachments
Ultimately I will go aperiodic. But as Shiirn mentioned in the thread its a learning experience so I am measuring as I go. I will probably add the side walls soon and measure that as well.... But yeh the aperiodic box is awaiting.
How come the response goes up past 3k? Is that connected to the open baffle?
As I said earlier, the response of your mid/bass driver will not stop dead at the frequency of 2,000Hz mentioned in its specs. Its response will extend to at least an octave higher.
OK, this implies Cms changed, so what are the new BL, Qms, Qes, Qts?
Back then, Altec 515B's 4.5 mm Xmax was a big number for a 15", so 10" will be somewhat lower, probably the ~1 mm of most drivers.
GM