Port Noise

[mechanical73]

I just finished putting this sub together out of a sonotube and an Audiopulse AX-15. It sounds great for movies but I notice some port noise when I play music loudly. The noise is not that noticeable during movies.

Specs are:
AX-15 sub
16in SonoTube X 36 in. high
(1) 4 in flared port from PE - 17 in long (tuned to 20 hz)
Sub is downfiring and the port is on top.
The end caps are 1.5 in. thick MDF.

The obvious problem here is I am limited by the length of port I can fit as the Audiopulse is almost 10 in. high - leaving me less than 26 in for the port.

If I go to a 6 in. I would need almost 40 in. to get close to the same tune frequency.

Do you guys have any suggestions ?
I don't know of any way to get a u-shaped 6 in. bend that will fit within the 16 in. sonotube ?

 

[croseiv]

I find I have port noise too, but it usually goes away after about four hours (a little longer if I've eaten mexican food).

 

[speakerman39]

I find I have port noise too, but it usually goes away after about four hours (a little longer if I've eaten mexican food).

Hey croseiv, I have an older brother that has port noise regardless of what he eats! Heck, he doesn't even need to eat to have port noise. Lets just say he has no trouble clearing a room at the drop of a dime. Just think, I had to live with him when we were growing up too! I learned a long time ago, if my bro ever asks me to pull his finger that it is time to run.....run for your life! And, run I did.

Cheers,

Phil

 

[TLS Guy]

I just finished putting this sub together out of a sonotube and an Audiopulse AX-15. It sounds great for movies but I notice some port noise when I play music loudly. The noise is not that noticeable during movies.

Specs are:
AX-15 sub
16in SonoTube X 36 in. high
(1) 4 in flared port from PE - 17 in long (tuned to 20 hz)
Sub is downfiring and the port is on top.
The end caps are 1.5 in. thick MDF.

The obvious problem here is I am limited by the length of port I can fit as the Audiopulse is almost 10 in. high - leaving me less than 26 in for the port.

If I go to a 6 in. I would need almost 40 in. to get close to the same tune frequency.

Do you guys have any suggestions ?
I don't know of any way to get a u-shaped 6 in. bend that will fit within the 16 in. sonotube ?

The only way to fix it, is to find a way get a larger longer port in there. Nothing else will work. That is the only way to reduce vent air velocity.

 

[Gov]

I have daily port noise. My wife wants a divorce because of it. She has no sense of humor

 

[Warpdrv]

2 ways to fix this IMO,

Have the port stick out the top like a stove pipe or get a longer piece of sonotube and put the right size & length port in there...


Where do you live, I know someone that is discarding his sono sub, cause I just got his driver from it. Made for exactly the same driver mount.

 

[WmAx]

This is severely limiting the driver. At this point, there was no reason to get that driver. It can not work well in this cabinet and port system that you have chosen.

You need to build a proper enclosure with sufficient volume and port area.

-Chris

 

[markw]

You missed a golden opportunity here.

You should have called the title "Port Noise Complaint".

 

[j_garcia]

Have you thought about a higher tune for the size of enclosure that you have? How did you arrive at your calculated tune?

 

[mtrycrafts]

You should have called the title "Port Noise Complaint".

Interesting I was thinking on the same order

 

[mechanical73]

I used the speaker manufacturer spec's on the enclosure size which is 4.2 cubic feet and tuned to 22 hz.

I am going to try two 3 in OD., 17 in. long ports to see if this helps.

 

[annunaki]

Two 3" ports will net you 14.14 in^2 of port area. a single 4" port yields 12.5in^2. It is not a significant increase. It MAY help ever so slightly. What about 3-3" ports? I am unsure what the length would be.

If your caps are made of MDF, it would be possible to re make them for use with square or rectangular vents yielding more surface area. 5"x5" would be equal to 2 4" ports. You could make it 20" long and then double back on itself. Router all the edges and you would be all set.

Kind of like this: (hopefully it works)



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