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I have Made a strong double floor/double baffle box with window bracing out of 3/4 MDF just a bit larger than spec . I am using white sewer pipe so I can run the sweep 90's and dual 4" precision port flares top and bottom for a single 12 in a test box and keep changing my tuning,
I have a cheapo db meter on the dash while running all my tests. Here's where I need you guys because I'm stumped. So why when I make the ports longer (tuned lower) would my 30 to 35hz range numbers drop? also why when I shorten the ports (tuned higher) would 56-62hz range numbers drop? I also cant figure out why I'm so peaky I have some notes like 40hz almost always falls on its face. Tuned at 31.5 and 32 it dies but tuned at 31 it doesn't? (I'm talking a whole 8db) I also usually have a drop at 42Hz,43hz,and 52hz. I'm just lost as to why the numbers are so jumpy between tests. Why its a steady climb with drops and then back to a steady climb then drops etc. I start at 30hz and go to 62hz during these tests.
I honestly always thought the low range to a point would gain at lower tuning while sacrificing some higher notes and vice versa. Can someone tell me from experience in a test box with meter is this normal and how do you decide on a final tune? Is there an easy way to rid myself of the random peaks and drops? Every time I change the tune some numbers go up and some numbers go down but not consistently on either end as you would think. It seems random. I love the 30-40 range
Thank you in advance for taking time to read and respond. This place is the best. If anyone can set me straight it will be here.
I have 4 Powerbass 1204D 12" subwoofers which have a frequency range of 31-500hz and I'm building a custom box
Manufacturer recommends 10 cubic foot box (ported) tuned to 34hz subsonic at 37hz?? which confuses me?
My question is if I tune my 10 cubic foot box (ported) tuned to 32hz subsonic at 25hz. (24hz would be half an octave lower than tuning or the unloading point as I understand)
Will I be asking for trouble? or am I ok, I have done a lot of reading and still not sure on this topic
I like the lows, at the same time I don't want to toast my subs.
Any advice or input will be appreciated?
By Paul Kadoshnikov
In regards to the image, here is my design for 2 warden 21" subs. Box is about 17.5 cubes total after displacement and some bracing. Port will be about 12" wide by 22.5" (internal dimensions) long about 33hz tuning (270" port area).
So my question is, I can leave the spot underneath the port without a separator wall, or I can add a separator shown on the right. Aside from adding bracing to the box, would it lower port tuning a little? (in the thought of the air will hit the divider and move up, as if adding some port length?)
If the subs allow I may make the port slightly longer, but tuning would max go to 31hz even if i add 6 inches internally to the port. So I dont think I will extend it if the box allows. The port will be pretty close to both woofers.
I intuitively don't think it'll affect port tuning, but would it cause any issues adding the separator almost up to the port?
Or if anyone has some input on changing where the port goes. The sides are very close to the vehicle walls so a port to the side may not be the best. And there isnt room to port forward.
I think the thread speaks for itself, I wish to buy a CC-1. BUT, I'm in Europe, the Netherlands. The often suggested places to look have 0 stock (bladeice etc.).
And yes, I am aware this is probably a long shot, but I'll try to buy one here for a reasonable price shipped.
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