I have been reading every thread I can find about slot loaded open baffle projects and while there's tons of great info I can't seem to find anything about how to actually calculate the distance/volume of the baffle from the cone. Someone in one thread eluded that you do it like a 4th order bandpass but I've tried that on a couple of calculators by making the sealed section enormous and the vented section tiny and adjusting the vent size but the numbers either error or don't make any sense on the output end, coming in at like -30db from the plain Open Baffle models. I've attached a photo of a design like I'm looking to build and highlighted the area I'm referencing. Can anyone help me out here? I think I've waded into the deep end of the pool. TIA.
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The slot is a back loaded horn low pass filter where the 'horn' [baffle] in this case is a flat one, so might can sim it in HR if its BLH Wizard is up to the task, so query DMB.
GM
GM
The effect will be only in higher frequencies depending on the size of the front chamber. there will not be much difference in much higher frequencies either, as long as the driver is visible through the slot. Try to simulate it and see the boost at 3-400Hz.
Better to construct a band-pass
did not see the photo
Better to construct a band-pass
did not see the photo
Sorry about the photo. Something must have happened when I edited the original post. It's attached now.
After a couple more hours of looking around I found "slot area is approximately 1/3 to 1/4 of the driver total Sd, depending of xmax of the speaker", "Driver total SD would mean all of the drivers sharing the same air space. If you have a 10" speaker with 340cm2 of SD, then you need 85-170 cm2. If you put a 2nd 10" woofer in the same cabinet, you would need to double that area." Seems legit, but a little loosy-goosy. Now with the new info above I can maybe try to model it in software and see if the two jive.
Thanks all.
After a couple more hours of looking around I found "slot area is approximately 1/3 to 1/4 of the driver total Sd, depending of xmax of the speaker", "Driver total SD would mean all of the drivers sharing the same air space. If you have a 10" speaker with 340cm2 of SD, then you need 85-170 cm2. If you put a 2nd 10" woofer in the same cabinet, you would need to double that area." Seems legit, but a little loosy-goosy. Now with the new info above I can maybe try to model it in software and see if the two jive.
Thanks all.
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Hmm, drivers designed for compression horn loading are normally limited to 3:1 CR, but short 'horns' can be up to 10:1, so will just depend on the drivers , baffle loading used.
GM
GM
Re the tapered slot, FWIW, the pioneers used 1/8 - 1/16 horn segments of the fundamental for tuning large reflex alignments, so seems reasonable to use this as a basis for floor loading.
GM