What about the f18 sealed vs the vft15h I would all ways go sealed versus ported usually due to port chuffing, but if I'm not missing out as much the vft15 is hard to beat. Just that port chuffing.
Nearly any ported sub can be made to chuff if you push it hard enough. On the other hand, any sealed sub can be driven past Xmax and run into heavy distortion or even bottoming out when pushed hard enough. The difference is that ported subs will not run into chuffing nearly as quickly as the sealed sub reaches its Xmax limits.
And is that 4db worth it for double the price if I was to go ported? If not my choice would be probably between the sealed f18 or the ported vft15 just do to the price difference if I were to go that high in price I would want sealed do to if it port chuffs I won't be as happy than if the Hsu port chuffs I won't mind as much because I didint pay as much, and I've even heard SVS pb16s port chuff
If you want to avoid port chuffing, one thing that can help is to look at port diameter vs port tuning. A smaller diameter port with a deep tuning frequency will chuff a lot sooner than a larger diameter port with a higher tuning frequency. The SVS PB16-Ultra and the FV18 both have three 3.5" ports. The VTF-15h MK2 has two triangular ports that have the equivalent cross-sectional area of 4.5" ports. If you add up the total area of these ports, three 3.5" ports have about the same area as two 4.5" ports, which thirty square inches. However, since the FV18 is tuned to deeper frequencies than the PB16-Ultra or VTF-15H mk2, it may be more susceptible to chuffing. But the shape of the port makes a difference too, and we don't really how well a triangular port fares against a round port. My guess is that the triangular shape doesn't really help. However, It has been shown that a deeper and more gradual port flare like what the VTF-15H mk2 has is better in thwarting turbulence than shallow flares at the tips of cylindrical ports like the PB16-Ultra and FV18 have. So that might help to offset any disadvantage that a triangular port has. What is more is that the VTF-15H mk2 and PB16-Ultra ports do not have any bends in them which will help to discourage port turbulence. One thing you can do to deter port turbulence when you have a bend is to have a larger cross section at the bend. The only subs I have seen which do that are Hsu subs, and I think Dr. Hsu actually holds a patent on how to do that optimally.
I would say that if you really want to avoid port chuffing, whatever sub you get, run it with all ports open and set to the corresponding amp setting. My guess is that the VTF-15H mk2 is less likely to chuff than the FV18 if you run these subs with all ports open and you push them hard.
Something else to keep in mind is that chuffing can serve as a warning when you are pushing the sub too hard. With a sealed sub, you might not notice any warning until the sub bottoms out. The problem is that bottoming out the driver can lead to its destruction. If you run into chuffing a lot, at least that is a sign that you may want more headroom that doesn't put the sub in danger.
