Do all Ported Subs fart ?

DodgeTheViper

Moderator
Do all Ported Subs make a farting/rattling type noise when pushed a little ?

From what I’ve heard, a lot of them appear to make this type of noise. I wouldn’t want to be watching a good movie and be greeted by an almighty fart at the crucial moment :D

Is it normal ?
 

WozzaB

Well-known Member
Well I can say that the XTZ 12.17 Edge's I just got haven't farted so far and they shook the flat like never before this week!! They seem to be prone to farting/chuffing, reading posts on here, so maybe having duals has negated that?
 

WozzaB

Well-known Member
I was worried that the rear sub that is just behind the sofa in the corner would be easy to localise if it started chuffing! It's shaking the sofa a lot and no farting so far thankfully!
 

DodgeTheViper

Moderator
That’s good considering how close you appear to have that one.
 

WozzaB

Well-known Member
Yeah it's almost touching the sofa and the seat closest to it vibrates like mad! Nice!

I really was worried about trying a ported again after not getting on the with the PB2000, but the XTZ's are behaving nicely in my room, very happy with them, but I know they're not in the same league as what you're after though😅
 

DodgeTheViper

Moderator
I’m not doubting their ability one bit. It’s more the Ported farting thing I’m querying, which may be attributed to the design etc.
 

WozzaB

Well-known Member
I'm sure a few people think the XTZ 12.17 cabinet is too small and contributes to the chuffing they have had, this possibility made me skip them previously, but one popped up really cheap so I gave it a go and then bought a 2nd pretty soon after!
I was listening for port noise for the first day or so, none heard. I did play Man of Steel 4K this week and the bass was the craziest I've had in my room and still didn't hear any port noise, that was around -12/-10db volume on the Denon AVR, maybe I'm not pushing them right to the max like some do?
 

rccarguy

Active Member
It's called chuffing. Noticed it on my pc ultra with two ports plugged but not with one or no ports plugged.
 

Liammonty123

Well-known Member
Well designed ones don’t. A well designed ported sub has sufficient port area and length so air velocity does not become audible when the driver reaches its excursion limits or at tune, and also has a 1st port resonance that is out of the passband. Basically both which lead to large boxes for a certain driver size. Sometimes compromises have to be made commercially and big box sizes aren’t usually popular. An undersized box usually means an undersized port which may cause audible turbulence or ‘chuffing/farting’.

I’ve pushed my 21s to audible excursion distress without chuffing from the ports.
 

Liammonty123

Well-known Member
It's called chuffing. Noticed it on my pc ultra with two ports plugged but not with one or no ports plugged.
This is expected, blocking ports reduces total port area, increasing air velocity in the one point, maximising the probability of audible chuffing.
 

DodgeTheViper

Moderator
Well designed ones don’t. A well designed ported sub has sufficient port area and length so air velocity does not become audible when the driver reaches its excursion limits or at tune, and also has a 1st port resonance that is out of the passband. Basically both which lead to large boxes for a certain driver size. Sometimes compromises have to be made commercially and big box sizes aren’t usually popular. An undersized box usually means an undersized port which may cause audible turbulence or ‘chuffing/farting’.

I’ve pushed my 21s to audible excursion distress without chuffing from the ports.
I'm guessing that without knowing the build diagram etc, one wouldn't know without actually trying it.
 

StefanBFC

Well-known Member
Mine haven't at all, they just rattle everything else in the living room if they are not glued down, and I mean everything!!
 

Gasp3621

Distinguished Member
Often you see some stupidity regarding the port noise. And it´s the silly 30sec start of Edge of tomorrow played very loud with the sub running hot trying to play 10hz sine wave. Then they bash the product totally. Do the guys watch that start on repeat all day every day? :suicide: If it would be constant issue people would move to large sealed subs, but you don´t really see that happening in US. I would say quite the opposite seeing many has returned SB16U for PB16U just as an example and they have been quite blown away for the extra impact/tactile sensation.

@DodgeTheViper you should really consider the dual Monolith 15s if American Audio gives the AVF discount and you can fit them! They have good design and the port noise shouldn´t be issue if believing the owners words at AVSF. While they offer superb performance there is also intresting thing what many says and it´s how the subs sound different to many other brand, and in positive way. Amps come from Claridy Audio with 5year warranty.

 

MI55ION

Distinguished Member
As well as what's mentioned above regards to design, it mostly depends on the port tuning, how loud you like to play them, the number of subs you use and the room size.

Take for example dual Monolith 15Us from Monoprice, I would imagine in a typical UK living room you'd have to be pushing them to insane levels at very low frequencies to even begin to hear any port noise.

The efficiency and trouser flapping potential of ported subs is not to be scoffed at.
 

DodgeTheViper

Moderator
Often you see some stupidity regarding the port noise. And it´s the silly 30sec start of Edge of tomorrow played very loud with the sub running hot trying to play 10hz sine wave. Then they bash the product totally. Do the guys watch that start on repeat all day every day? :suicide: If it would be constant issue people would move to large sealed subs, but you don´t really see that happening in US. I would say quite the opposite seeing many has returned SB16U for PB16U just as an example and they have been quite blown away for the extra impact/tactile sensation.

@DodgeTheViper you should really consider the dual Monolith 15s if American Audio gives the AVF discount and you can fit them! They have good design and the port noise shouldn´t be issue if believing the owners words at AVSF. While they offer superb performance there is also intresting thing what many says and it´s how the subs sound different to many other brand, and in positive way. Amps come from Claridy Audio with 5year warranty.

I think that's what i've been looking at too much, the intro scene in Edge Of Tomorrow and the Subs not sounding good at all. Almost like they're about to break up.
 

MI55ION

Distinguished Member
I think that's what i've been looking at too much, the intro scene in Edge Of Tomorrow and the Subs not sounding good at all. Almost like they're about to break up.
You know a BOSS platform would easily cure this cursed scene without a hint of stress from the actual subwoofers.

 

DodgeTheViper

Moderator
You know a BOSS platform would easily cure this cursed scene without a hint of stress from the actual subwoofers.
Yeah maybe but that's not a road I'm even considering treading down.
 

MI55ION

Distinguished Member
Yeah maybe but that's not a road I'm even considering treading down.
Fair enough, the only other option I see that can easily take that scene without breaking a sweat or huffing and puffing is a set of multiple (more than two) 15"/18" subs.
 

Liammonty123

Well-known Member
As well as what's mentioned above regards to design, it mostly depends on the port tuning, how loud you like to play them, the number of subs you use and the room size.

Take for example dual Monolith 15Us from Monoprice, I would imagine in a typical UK living room you'd have to be pushing them to insane levels at very low frequencies to even begin to hear any port noise.

The efficiency and trouser flapping potential of ported subs is not to be scoffed at.
It doesn’t really have anything to do with port tuning, a High tuned port with insufficient port area will still chuff, the same as a low tuned port. It’s all about port cross sectional area, within limits.
 

MI55ION

Distinguished Member
It doesn’t really have anything to do with port tuning, a High tuned port with insufficient port area will still chuff, the same as a low tuned port. It’s all about port cross sectional area, within limits.
Agreed that makes sense.

Say you have two subs, one tuned to 20hz and the other to 10hz, depending on content/source would the lower tuned sub be less susceptible to audible chuffing given the limits of cross sectional area?
 

Liammonty123

Well-known Member
Agreed that makes sense.

Say you have two subs, one tuned to 20hz and the other to 10hz, depending on content/source would the lower tuned sub be less susceptible to audible chuffing?
Completely dependant on the ports of said subwoofers. If both subwoofers have ports with sufficient area, neither will have more chuffing than the other.

If you had a subwoofer with 2 ports tuned to 20hz, blocked off one of the ports for say a 15hz tune, the area has been halved, and so velocity should double, meaning more chuffing!
 

ashenfie

Well-known Member
Block all ports. Most subs come with bungs. Loss some frequency response but no chuffing and faster bass
 

DodgeTheViper

Moderator
Completely dependant on the ports of said subwoofers. If both subwoofers have ports with sufficient area, neither will have more chuffing than the other.

If you had a subwoofer with 2 ports tuned to 20hz, blocked off one of the ports for say a 15hz tune, the area has been halved, and so velocity should double, meaning more chuffing!
Are slotted ports more or less prone to the problem ?
 

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