.The easiest way to do that is to use the Loudspeaker Wizard and change the slot size by adjusting the S1 slider (S3 will follow automatically).
Change the size of the W outer "wings" by adjusting the S5 slider (S3S will follow automatically).
Those caution messages mess with my head. I was getting 1 with the OD function when trying to use a 2.75in Lrc and a Vrc of 12.75in x 12.75in x 2.75in (I'm on my phone).
Of course it went away when I used 1.375in, but the Schematic Diagram screen did not look right to me visually.
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Correct. DMB's models had me scratching my head with L12 and L23 totaling 12in when the driver is 12.25in. However, he was going off your request.
If you are going to do top and bottom panels, then 12.625in is definitely the way to go.
Cabin gain (transfer function) is a beautiful thing! The bass is effortless.
My son thinks it sounds better than the single 12 BP4 that was not designed for the Crown Vic. A Toyota Solara is a lot smaller car.
Identical results can be produced using CH3. The downsides are that the path length is no longer automatically calculated and the area and length sliders are all independent of each other, making it more messy when trying to optimise a W-frame design in the Loudspeaker Wizard.
So far, these models show the potential resonant spike around 300hz from the cavity. Just some quick dirty math, if the cavity is 12" deep on one side and 1.25" half way to the center of the width of the cavity (total width 2.5"), that's 13.25" as a quarter wavelength, so 4x this is 53" or 1.34m. And 1.34m wavelength is 256hz. So that's pretty close to the horn resp spike there around 250~300hz range.
If that correlates, I'm curious now how the width of the cavity will move that spike. The height and depth are largely fixed due to piston size (which a 12" driver has a moving piston around 10" diameter in reality, so I could try to squeeze in the cavity a bit more, like 11" or so. So even if I dropped it to 11" depth, 11" height and 2" width, the quarter wave is 12" and full wave is 48" or 1.21m which is around 277hz. Only went from 256hz to 277hz with that small reduction, so basically not worth it.
I only need to get to around 100hz, but of course would probably want that massive cavity resonant spike to be at least an octave up, so if I want 100hz that means more like 200hz. So I could probably increase the cavity width a little. Working backwards from 200hz, we have a 1.5m wavelength. 1.5 / 4 = 0.375m wavelength quarterwave, which is 14.76 inches. If my cavity height and depth are about 11" minimum, that leaves me 3.76" to the center of a cavity, allowing a total cavity width of 7.52". But this is probably too wide and will not mass load the drivers in the slot.
I'm curious though if the Horn Resp simulation will predict this resonant spike around 200hz if the cavity width goes to 7.5 inches (19cm). If so then maybe this sim is close to what the cavity is doing?
Then final thing I'm curious about, is that's just 2 drivers and I will likely scale this to 8 total drivers, 4 pairs, each with its own isolated slot like this. Is it possible to simulate in Horn Resp 4 of these cavities operating together in a vertical array?
Thanks all so much, this has been super helpful.
Very best,
If that correlates, I'm curious now how the width of the cavity will move that spike. The height and depth are largely fixed due to piston size (which a 12" driver has a moving piston around 10" diameter in reality, so I could try to squeeze in the cavity a bit more, like 11" or so. So even if I dropped it to 11" depth, 11" height and 2" width, the quarter wave is 12" and full wave is 48" or 1.21m which is around 277hz. Only went from 256hz to 277hz with that small reduction, so basically not worth it.
I only need to get to around 100hz, but of course would probably want that massive cavity resonant spike to be at least an octave up, so if I want 100hz that means more like 200hz. So I could probably increase the cavity width a little. Working backwards from 200hz, we have a 1.5m wavelength. 1.5 / 4 = 0.375m wavelength quarterwave, which is 14.76 inches. If my cavity height and depth are about 11" minimum, that leaves me 3.76" to the center of a cavity, allowing a total cavity width of 7.52". But this is probably too wide and will not mass load the drivers in the slot.
I'm curious though if the Horn Resp simulation will predict this resonant spike around 200hz if the cavity width goes to 7.5 inches (19cm). If so then maybe this sim is close to what the cavity is doing?
Then final thing I'm curious about, is that's just 2 drivers and I will likely scale this to 8 total drivers, 4 pairs, each with its own isolated slot like this. Is it possible to simulate in Horn Resp 4 of these cavities operating together in a vertical array?
Thanks all so much, this has been super helpful.
Very best,
Well, version 50.70 does not have the OD3 function.
I'm glad I was on the right track. Your CH3 model matches my previous OD model.
Ok, let's see if I was able to go a similar pathway as you guys.
I updated it to allow for my intended drivers which is 8 total drivers, two banks in series and then wired in parallel to the amp.
I massively increased the cavity width just to see what it does. It improves the low knee around 25hz. But it's too wide and won't mass load the drivers. Still, a helpful thing to see I think.
Very best,
I updated it to allow for my intended drivers which is 8 total drivers, two banks in series and then wired in parallel to the amp.
I massively increased the cavity width just to see what it does. It improves the low knee around 25hz. But it's too wide and won't mass load the drivers. Still, a helpful thing to see I think.
Very best,
Yes, the cavities will be isolated per 2 drivers, because one long cavity would have more problems. So every 2 drivers will be face to face with a cavity between them like in the W frame slot loaded baffle graphic from before. But there will be 4 total of them. I imagine it's nearly impossible to simulate 4 separate cavities like this accurately, so it was mostly to get an idea of what 2 in a cavity would do and then just increase to 4 of them. This may not work in the sim, I'm not sure. The final build however will use 8 drivers per open baffle like this. I'm mainly trying to simulate the slot width and its effect on the cavity and resonance and then of course total baffle width effect on the frequency response shape.
I hope to put a rough physical model together next week or so to be able to test it. It's just nice to see if any of the sims then predicted anything with good correlation to the physical model.
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I've already used these drivers in a platform open baffle like this:
I ran it from a 300w amplifier and a DSP to boost and flatten to 10hz. This is just a few db under hitting mechanical limits of the excursion. I don't care about distortion at 10hz. This is at about 1 meter distance from the drivers above them. So, I figure, if I can get this response from these drivers on a baffle like this, I want to try 8 of them in a tower baffle arrangement slot loaded and see what I can get out of it.
The slot load is less about output for me, and more about being able to arrange in dual opposed to cancel vibration forces on the baffle but without canceling the output due to being on two separate baffles. But I don't want to make a slot that will then cause havoc with problems within the working bandwidth I'm targeting (10hz to 100hz). So, wanted to sim the cavity effect and where it will effect things in addition to just calculating resonance spikes based on the cavity so that I don't end up with some awful cancellation down in the 10~30hz range, as that would murder the goal.
Very best,
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The response I posted was DSP'd. That's not the natural response, just FYI. That also has room influence in it, not ground plane. So, you can't model that probably.
But if you wanted to model the natural result prediction here's dimensions:
The dimensions are 32" x 32" gross external. 1.5" internal lip under there, 3.5" around the perimeter (2x4's). Central brace is 1.5" x 3.5" x 29" length. The platform is 6.5" depth from flange of driver to the floor where the feet in the corners touch. This can slide under a cough, bed, coffee table, etc.
Very best,