Hi there, I need help to model a subwoofer for my camper/RV.
From what I have read a push-pull alignment works well to prevent vibration and reduce stresses on the box construction, a significant feature when building subwoofers into furniture.
Since space is limited I have decided to remove the bottom drawer from the kitchen cabinet, that's the free space to use. Max 35lit.
Since the floor and walls are there already they will be integrated into the build, they are made out of birch-plywood and I will add braces for extra support and stiffen the walls.
A drive I have considered for this project is the 6.5" Tang Band W6-1139SIF, any other recomendations of suitable drivers are welcome.
Do the drivers have to be in an opposing alignment to prevent vibration?
Or could they be mounted facing forward on the same baffle and still benefit from less vibration?
From what I have read a push-pull alignment works well to prevent vibration and reduce stresses on the box construction, a significant feature when building subwoofers into furniture.
Since space is limited I have decided to remove the bottom drawer from the kitchen cabinet, that's the free space to use. Max 35lit.
Since the floor and walls are there already they will be integrated into the build, they are made out of birch-plywood and I will add braces for extra support and stiffen the walls.
A drive I have considered for this project is the 6.5" Tang Band W6-1139SIF, any other recomendations of suitable drivers are welcome.
Do the drivers have to be in an opposing alignment to prevent vibration?
Or could they be mounted facing forward on the same baffle and still benefit from less vibration?
Tachyon,
1) Yes, either "push pull", with one driver's polarity reversed, or "push push", with the same polarity in an opposing alignment will reduce transmitted vibration.
2) No, both drivers facing forward on the same baffle will double the vibrational effect, and if one was reversed polarity it would largely cancel any low frequency output.
That said, the vibrations can give a "sense" or "feel" of low frequency in the RV without transmitting the low frequency sound to other campers.
Consider the locations under seating areas before giving up the bottom drawer of the kitchen cabinet.
Art
Thank's Art for the clarification on push/pull and push/push.
I did at first consider the space under the sitting area but that is where the wheel arches are and this truck has dual rear wheels, DRW, no free space.
Since all the panels of the speaker is "blocked" except the front baffle is there any way to implement a push/pull or a push/push in that space?
I did at first consider the space under the sitting area but that is where the wheel arches are and this truck has dual rear wheels, DRW, no free space.
Since all the panels of the speaker is "blocked" except the front baffle is there any way to implement a push/pull or a push/push in that space?
Slot load the drivers so they face each other, push-pull can be done but more troublesome. Some builders make the slot narrower at the back to reduce resonance.
The plenum (slot) can be located with both speakers on the front baffle. The plenum can be made smaller in a push-push configuration, as the magnet structure is not in the plenum. As phivates mentioned, the plenum can be "V" shaped if a push-push configuration is used.
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Thank's Art and phivates!
How about mounting the drivers as in the picture?
The slot is only 5cm if using the Tang Band W6-1139SI.
Space is limited..
How about mounting the drivers as in the picture?
The slot is only 5cm if using the Tang Band W6-1139SI.
Space is limited..
An externally hosted image should be here but it was not working when we last tested it.
I would mount the drivers with the cones vertically oriented; as drawn the cones may sag. Your cabinets will appreciate the reduction of vibration, as will the contents.
Thanks Phivates, hopefully the cutlery will not jump around to the music 🙂
Now if anyone would be so kind and help me model this out in WinISD or Hornresp, I'm a complete newbie to both and would really appreciate some help.
Thanks you!
Any advantage from mounting one driver inverted?
An externally hosted image should be here but it was not working when we last tested it.
The only advantage is if the drivers are prone to non symmetrical excursion due to imprecise assembly then the (mostly) second order harmonic distortion will cancel out. If they are well made then I wouldn't bother. I used to be a push-pull believer by the way. I suspect the TB drivers are good enough not to bother.
With face to face, or back to back, the stress will be symmetrical; the airflow in the back of the woofer is a bit limited by the magnet and woofer.
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Thank's guys, I found this thread on PPSL "push-pull slot loaded" that I'm soaking up at the moment.
A Thread for those interested in PPSL enclosures
"The cancellation is only for the 2nd harmonic distortion. This is caused by an asymmetry when the cone goes inward vs outward. "
"When you turn one of the drivers around you get an automatic S2 correction"
"As far as canceling vibration forces, face to face, magnet to magnet, or push pull (magnet to cone) are all equally effective. Your infinite baffle system could have reduced even order harmonic distortion had you used push- pull mounting."
I'm getting my head around software simulation, calculate area/compression ratio for the plenum, inverted drivers etc.
A Thread for those interested in PPSL enclosures
"The cancellation is only for the 2nd harmonic distortion. This is caused by an asymmetry when the cone goes inward vs outward. "
"When you turn one of the drivers around you get an automatic S2 correction"
"As far as canceling vibration forces, face to face, magnet to magnet, or push pull (magnet to cone) are all equally effective. Your infinite baffle system could have reduced even order harmonic distortion had you used push- pull mounting."
I'm getting my head around software simulation, calculate area/compression ratio for the plenum, inverted drivers etc.
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