@All
I was also thinking to an horizontal speaker. Something like this
http://www.troelsgravesen.dk/BOOKSHELF-3WC.htm
this would remove the 63cm height constraint and allow me to size the cabinet better.
In fact I forgot to ask about the sizing of the cabinet. Once I have defined the volume, how I should size the cabinet?
I was also thinking to an horizontal speaker. Something like this
http://www.troelsgravesen.dk/BOOKSHELF-3WC.htm
this would remove the 63cm height constraint and allow me to size the cabinet better.
In fact I forgot to ask about the sizing of the cabinet. Once I have defined the volume, how I should size the cabinet?
So...
after some days of meditation and study, I decided to maintain the vertical orientation and buffle size of 63 x 38 cm, but I increased the dept to 53 cm.
In this way the final internal volume id 99,1L. I also reduced the volume for the midrange and tweeter to 8L. So the total volume for the woofer is around 88L and the resonance frequency is 27Hz.
I also changed a bit the position of drivers on the buffle.
W -> 190, 170
M -> 265, 415
T -> 265, 555
I also lowered the 3 crossover frequencies. So this is the final result
This is the buffle draw with also the tube positioning.
What do you think? Any comment that can help?
after some days of meditation and study, I decided to maintain the vertical orientation and buffle size of 63 x 38 cm, but I increased the dept to 53 cm.
In this way the final internal volume id 99,1L. I also reduced the volume for the midrange and tweeter to 8L. So the total volume for the woofer is around 88L and the resonance frequency is 27Hz.
I also changed a bit the position of drivers on the buffle.
W -> 190, 170
M -> 265, 415
T -> 265, 555
I also lowered the 3 crossover frequencies. So this is the final result
This is the buffle draw with also the tube positioning.
What do you think? Any comment that can help?
I like the x-over. I would investigate port location issues. It's not something I'm familiar with, but a port resonance can be an issue. I'd ask in a separate thread, just to make sure there's not going to be an issue..
With this crossover that won’t be an issue. The mid enclosure can be a lot smaller than 8l by the way.
I agree. The enclosure height will lead to a mode at (34300 / (2 * ~60)) = 285 Hz, but the port in the middle is at the pressure minimum and will not transmit this mode.
thanks for the answer.
I was also looking to the phase graph. Should I introduce a z-offset to align the 3 phases?
I was also looking to the phase graph. Should I introduce a z-offset to align the 3 phases?
Not needed (as far as I know), you should only align the phases of the crossed over drivers at their x-over frequency range. That is the case already.
Did you incorporate phase info from the drivers’ response into the sim? I suggest that you check the response of the build, once completed.
It's a gated measurement, adjust the window/number of cycles to exclude or include the room, as desired.
I am certainly no expert here ... but adjusting the settings is quite intuitive.
CSD and burst decay plots are best obtained within any distance from 0,5cm to 30cm from the cone, the latter like distortion measurements. You mostly need them to assess the driver behavior, so you don’t need full integration of baffle step effects, diffraction effects from corners or input from other drivers.
That changes of course when you want to measure the whole system and need to measure at 1 to 2m from the speaker. In that case you have to get rid of early reflections the first 8-10ms or so. Either by lifting the speaker up in open air or by performing solid ground plane measurements.
I might stress the importance of a solid measuring protocol here, like Hifijim and others have advocated. For a once in a lifetime project that probably is overkill, but make your measurements repeatable. Record all positions and settings and check carefully.
That changes of course when you want to measure the whole system and need to measure at 1 to 2m from the speaker. In that case you have to get rid of early reflections the first 8-10ms or so. Either by lifting the speaker up in open air or by performing solid ground plane measurements.
I might stress the importance of a solid measuring protocol here, like Hifijim and others have advocated. For a once in a lifetime project that probably is overkill, but make your measurements repeatable. Record all positions and settings and check carefully.