OK I mostly finished one of my cabinets... I haven't put the chamfer on the baffle yet as I don't have the veneer, and the back is only being held on with strap clamps, but it seems ok....
I did acoustic measurements and my MW144's performance is looking far from good. They are really smooth on a nearfield measurement up to about 1Khz, but when I measure onaxis at about 85cm they are realy bad.
I managed to do some simulation in speaker workshop and found that a second order LR crossover on the woofer at about 1Khz, with a 2nd order LR on the tweeter at about 2.2Khz + and lpad at about 4.5db cut gave something aproaching a smooth response, almost completely compensating for baffle step (probably too much so!).... but what is really bugging me is that the MW144 should be much smoother than this, and I can't work out why it has a massive dip at 2.3Khz and then lower response from about 3Khz to 5Khz.... It sort of corresponds to simulations in BDS (as far as the curve shape is concerned) but the magnitude is much greater! BDS shows a dip of about 3db at 2300Hz but I'm, getting about 12db!! also BDS only shows about 1db difference between the trough and the frequencies from 3Khz on, but I have 3db.....
The attached pic shows the woofer repsonse + tweeter response (in red).... I think based on the fact that the tweeter isn't showing big dips at 2.3K I can rule out my mic as being dodgy (though I still may try another wand...)
I've tryed lining the walls with foam, and putting in polyester stuffing, this had no effect on the dip at 2.3Khz, but did remove a nasty peak (of about 6db) at 5Khz.....
Should I beleive the results I'm seeing and design my crossover with that, or should I try and get to the bottom of why I have such a large dip???
Is it likely that this is the actual response of my drivers?? or some other factor like standing waves or baffle diffraction.
Tony.
I did acoustic measurements and my MW144's performance is looking far from good. They are really smooth on a nearfield measurement up to about 1Khz, but when I measure onaxis at about 85cm they are realy bad.
I managed to do some simulation in speaker workshop and found that a second order LR crossover on the woofer at about 1Khz, with a 2nd order LR on the tweeter at about 2.2Khz + and lpad at about 4.5db cut gave something aproaching a smooth response, almost completely compensating for baffle step (probably too much so!).... but what is really bugging me is that the MW144 should be much smoother than this, and I can't work out why it has a massive dip at 2.3Khz and then lower response from about 3Khz to 5Khz.... It sort of corresponds to simulations in BDS (as far as the curve shape is concerned) but the magnitude is much greater! BDS shows a dip of about 3db at 2300Hz but I'm, getting about 12db!! also BDS only shows about 1db difference between the trough and the frequencies from 3Khz on, but I have 3db.....
The attached pic shows the woofer repsonse + tweeter response (in red).... I think based on the fact that the tweeter isn't showing big dips at 2.3K I can rule out my mic as being dodgy (though I still may try another wand...)
I've tryed lining the walls with foam, and putting in polyester stuffing, this had no effect on the dip at 2.3Khz, but did remove a nasty peak (of about 6db) at 5Khz.....
Should I beleive the results I'm seeing and design my crossover with that, or should I try and get to the bottom of why I have such a large dip???
Is it likely that this is the actual response of my drivers?? or some other factor like standing waves or baffle diffraction.
Tony.