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post #1 of 34 Old 01-16-15, 09:30 AM Thread Starter
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Seeking for help,

Hello,

I a couple of days hopefully my new sub will arrive finally. I am looking to build a enclosure for it. It is an Sundown audio e8 v4 sub. The sub will be placed in my room which is quite small and I will use the sub for both music and movies, so I would like it to go pretty low if that is possible, maybe around low mid 20s? The sub itself is 300 rms and will be driven by a 400 watt rms amp. I have no idea what type of enclosure is best for my situation, I thougt maybe a transmissionline, but the subs fs is pretty high because its an 8.

I hope someone could help me out on this, I will really appreciate it.


Abdullah,
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post #2 of 34 Old 01-17-15, 01:58 PM
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Re: Seeking for help,

I would suggest looking at a 3db extended bass shelf enclosure for this driver.
It gets down to 30 Hz and doesn't go over the manufacturers maximum box size specifications.
The box size is 0.62 cu ft (17.5 l) tuned at 29 Hz with a 4" port that is 63 inches long (this could be an issue for such a small box)

Seeking for help,-sundown-audio-e8v2d2.png

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post #3 of 34 Old 01-17-15, 06:45 PM Thread Starter
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Re: Seeking for help,

Thank you for your reply Robbo.
After I saw your reply I started to design something, this is what I came up with.

The box size is 17,5l and the portlength is 1600mm. I did let the port start at the side of the box and let it bend around halfway its length to come back againt to make it its full length. Around that I will make another box, you can see it as one giant box with a divider baffle in between. My question though is, the port starts really close to the sub, will this have any effects on the sound produced?
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post #4 of 34 Old 01-17-15, 06:53 PM
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I would check your port resonance frequency. With that lenght I bet it will be pretty low and could cause issue.
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post #5 of 34 Old 01-17-15, 06:57 PM Thread Starter
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Smile Re: Seeking for help,

I know, its just an idea sketch. There will be bracing added to the port. As if now it is impossible to make it because the box would be made from one solid peace I will design and detail it further later on, just want to know how you think about this design.
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post #6 of 34 Old 01-17-15, 07:04 PM Thread Starter
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Re: Seeking for help,

isnt it possible to make multiple short ports instead of one long port?
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post #7 of 34 Old 01-17-15, 07:53 PM
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isnt it possible to make multiple short ports instead of one long port?
if you increase the cross section you have to increase length. More ports equal more cross section so you have to increase the length to maintain the ratio.
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post #8 of 34 Old 01-17-15, 09:03 PM
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Re: Seeking for help,

That is what winisd comes up with, a 100mm port would need to be 1.6m long.

What you have sketched would certainly work if you added the bracing that you mentioned.
I look forward to seeing your progress on this.

You need to keep a minimum of 100 mm to prevent port "chuffing"

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post #9 of 34 Old 01-18-15, 09:55 AM Thread Starter
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Re: Seeking for help,

I played around with winISD my self for a bit because I am thinking that the other box is tuned a bit to high, how about something like this? (white graph is the old one, pink graph is the new one)
the box is 25l, about 3-4 liters more than the factory recommended boxsize. Port length and diameter stays the same which sould tune it around 24Hz. Will this be realistic for an 8'' sub at 400 rms? or should I keep with the original design?
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post #10 of 34 Old 01-18-15, 11:12 AM
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I would check cone excursion and port air velocity to see if it's all ok. First port resonance of 107hz is still and issue since you will most likely use the subwoofer at this frequency unless you lowpass at 80hz with something like 4th order.

Also I wouldn't care about manufacturer enclosure size. All the mather is the transfer fontion magnitude, cone excursion and power handling of the subwoofer. If all these are good looking and within spec I don't see why a smaller or bigger box would be an issue.
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