Looking for help and ideas: See picture: I believe this might be called a 5th order band pass using a 3” woofer. The idea is to give an extra boost in the bass without the 3” woofer adding to frequencies beyond 400 hz (thereby adding to the higher frequencies) by using a passive radiator whereas a port might leak some out.
The picture shows the bass section is enclosed with fabric all the way around and is solid in the front and back with audio out the sides. Assume the passive radiator is 2 times the SD and the PR plus woofer surrounds can handle the sag problem and no crossover (full range drivers.) My questions are:
1. Will there be a polar cancellation of the bass if I sitting in front of it? If so, then I will “unsolid’ the front and back and make it a 360 outlet.
2. To find the port length, should I simulate as if it is a basic reflex enclosure (as if the pink area is not there?)
3. I’m committed to the design, so are there other enclosure (non – electronic) ideas that might make the bass more prominent, i.e. place weights on the PR and/or driver and increase the power to the max excursion.
Thanks
The picture shows the bass section is enclosed with fabric all the way around and is solid in the front and back with audio out the sides. Assume the passive radiator is 2 times the SD and the PR plus woofer surrounds can handle the sag problem and no crossover (full range drivers.) My questions are:
1. Will there be a polar cancellation of the bass if I sitting in front of it? If so, then I will “unsolid’ the front and back and make it a 360 outlet.
2. To find the port length, should I simulate as if it is a basic reflex enclosure (as if the pink area is not there?)
3. I’m committed to the design, so are there other enclosure (non – electronic) ideas that might make the bass more prominent, i.e. place weights on the PR and/or driver and increase the power to the max excursion.
Thanks
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Hmm, FWIW my understanding is that a basic BR = 4th, add a front chamber = 6th, add a chamber in front of the PR = 8th or view it as a single driver dual BR = BP8. Wrapped in fabric makes them lossy.
1.Considering the sheer size of bass frequencies, seems to me like this oddball box wouldn't deviate much from a basic Karlson except maybe whatever impact the K's expo slot vent has.
2. No, though a place to start to empirically find how much shorter is required.
3. Adding PR weight tunes it lower, mechanically lowering Fs changes its specs, hence alignment, so the two combined will shift Fb lower at a lower efficiency.
1.Considering the sheer size of bass frequencies, seems to me like this oddball box wouldn't deviate much from a basic Karlson except maybe whatever impact the K's expo slot vent has.
2. No, though a place to start to empirically find how much shorter is required.
3. Adding PR weight tunes it lower, mechanically lowering Fs changes its specs, hence alignment, so the two combined will shift Fb lower at a lower efficiency.
Thanks for your reply. The reason I thought I would try this type of box is because i have a logitech z640 that has a 4" woofer and an 8" PR and has good low end (f3=40 hz). I want to make a much smaller enclosure and not emphize the frequencies above 400 or so by usiing the 3" facing out as in a BR. So is your idea that the bass coming out of the left and right slot will not somewhat cancel the bass sitting in front of the enclosure?
thanks
thanks
You're welcome!
It would comb filter up in the LF's response, which would be so rolled off it's probably only audible to a small animal. I mean even at 400 Hz were talking a ~13543/pi/400 = ~10.78" diameter sound 'bubble' and ~107.77" dia./40 Hz, so you tell me, maybe I'm having one of my 'can't see the forest for the trees' days. 🙁
It would comb filter up in the LF's response, which would be so rolled off it's probably only audible to a small animal. I mean even at 400 Hz were talking a ~13543/pi/400 = ~10.78" diameter sound 'bubble' and ~107.77" dia./40 Hz, so you tell me, maybe I'm having one of my 'can't see the forest for the trees' days. 🙁