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Discussion Starter · #1 ·
While the sims may not show a perfectly flat response with a larger enclosure, do remember to go large enough as to be able to use an adequately sized port (at least 8" diameter).
This is what I've got so far. I was really ecstatic to hear that Gen2 can be used in smaller enclosures until I saw the size of that port.



I would really, really prefer not to go larger than this, but am afraid there's still not enough clearance between the port and the driver :sad2: I am thinking of using 3 ports 4" wide which would give me an equivalent of 7" port (6.9 actually). Any reasons why I should not go that route?
 

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Re: Maelstrom-18" Gen II Landed

But I'll quickly tell you that you don't want a port length longer than 36"
I'm not sure why you would limit a port to 36 inches when ports in excess of 50 inches have been used will no negative effect as long as a 4th order 80 hz crossover is used and the first port resonance is 125 hz or higher.
 

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Mike I have to side with Steve on this one. I've not seen the data that convinces me that a 50" port is not going to have some audible issues in the pass band. I'm interested in seeing it if you have some links. I've seen a lot of people claim that it is fine, but you know how that is. Perhaps through creative bending, placement and damping/stuffing of the enclosure you can implement one well, but I would still hesitate to recommend it.

63hz 2nd harmonic is 125hz
42hz 3rd harmonic is 125hz
32hz 4th harmonic is 125hz

Distortion coud excite the port resonance and a crossover does not help with that.
 

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I remember that thread. I also remember not being totally convinced. Andrew's measurements were from 1" and did not include a complex sum of the port output mixing with the driver output measurement from a further distance such as 1m equidistant from the port and driver. They clearly show a very large spike in the upper port output. Also his enclosure has more attention to detail and also has a many folded port. Other people may not put so much effort into it. What if it's just a straight 50" pipe with no bends and not as much damping? The resonance will likely be stronger.

Someone should test this stuff...:whistling:
 

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Discussion Starter · #10 ·
I changed the effective volume to 370 l and the port is now 3'4" with 169Hz resonant frequency. I'm not really worried about resonance since I'm planning on getting a BFD. A simple notch filter would put that issue to bed (Isn't this the original purpose of BFD, surgically removing troublesome frequencies?).

I still don't know what's the minimal acceptable distance between the port and the driver. Any suggestions?
 
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