Hi,
It's like 2 face to face shallow U-baffles. So each of their 'rear' radiations is side-firing. And their 'front' radiations meet at the slot, then lead to a small window towards listener.
Or you may see it as an asymmetric dipole -- a concentrated lobe to the front, and a wide spreaded lobe to the rear, and mostly to both sides.
As far as I can tell, this center sub works very well with such condition. I haven't found any ill effect.
I had once built and used a W-baffle sub, which is very symmetric front to rear. Placed near the front wall, the cancellation by the reflection is obvious and makes it largely muted. Pulling it out away from wall would do significant improvement.
Forturnately, now this new one is doing much better with the wall.
It's like 2 face to face shallow U-baffles. So each of their 'rear' radiations is side-firing. And their 'front' radiations meet at the slot, then lead to a small window towards listener.
Or you may see it as an asymmetric dipole -- a concentrated lobe to the front, and a wide spreaded lobe to the rear, and mostly to both sides.
As far as I can tell, this center sub works very well with such condition. I haven't found any ill effect.
I had once built and used a W-baffle sub, which is very symmetric front to rear. Placed near the front wall, the cancellation by the reflection is obvious and makes it largely muted. Pulling it out away from wall would do significant improvement.
Forturnately, now this new one is doing much better with the wall.
Thanks for your interest.
Funny that it rarely happens that I don't keep detail record of my projects. And this is one of them. This sub was made of ready-made pine boards sold in hardware store, which are cut to many convenient dimensions for easy use of various tables, shelves etc. I just picked several proper sizes to fit my need for minimum cutting.
So I didn't draw the plan in detail and didn't keep it. I can only give you a guideline.
Roughly, it's overall 70-75cm wide by 60-65cm high by 50-55cm deep, 2 x 18" woofer - Emenince SigmaPro 18. The driver is not a good choice for dipole due to its low Qts and not so much Xmax. You can make any other pick for better conditions (easier co-work with ordinary amp).
As mentioned above, the frontal area of the slot is around 40% of Sd, which was taken from my own trial & error to fit the driver, space and my preference. (it's 30% or so in Nelson Pass's original design, IIRC).
I made a simplified sketch for your reference:
It's not to scale. And the 8 'studs' connecting 2 woofers are not shown.
Funny that it rarely happens that I don't keep detail record of my projects. And this is one of them. This sub was made of ready-made pine boards sold in hardware store, which are cut to many convenient dimensions for easy use of various tables, shelves etc. I just picked several proper sizes to fit my need for minimum cutting.
So I didn't draw the plan in detail and didn't keep it. I can only give you a guideline.
Roughly, it's overall 70-75cm wide by 60-65cm high by 50-55cm deep, 2 x 18" woofer - Emenince SigmaPro 18. The driver is not a good choice for dipole due to its low Qts and not so much Xmax. You can make any other pick for better conditions (easier co-work with ordinary amp).
As mentioned above, the frontal area of the slot is around 40% of Sd, which was taken from my own trial & error to fit the driver, space and my preference. (it's 30% or so in Nelson Pass's original design, IIRC).
I made a simplified sketch for your reference:
It's not to scale. And the 8 'studs' connecting 2 woofers are not shown.
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