Sealing ported cabs....

[greenboy]

Hence my original contention: People *think* ported cabinets are more efficient because so many of them have an amplitude peak in the low end.

And again, I'll say that people really should investigate typical driver/cab scenarios in a good sim program. Drivers chosen by bass cab manufacturers put into larger ported cabs - ones of optimum size for a flat curve to a low f3 - are going to have more output in that lower region wanted for bass guitar than sealed cabs of the same size with those drivers.

Really, take a look!

 

[A9X]

Right...and I'm sure you'd agree that improper execution occurs all the time in the MI business. Hence my original contention: People *think* ported cabinets are more efficient because so many of them have an amplitude peak in the low end. It may just be pure coincidence, but it only takes a small handful of coincidences for disinformation to become "conventional wisdom".

I have posted many times on this. I come from an engineering background and understand the theory so I know what can and can't be done. If someone believes something contrary to what can be done, that is their problem.

 

[Verne Andru]

If I'm reading this right, if you are upgrading speakers in a sealed cabinet, it's not advised to add a port during the upgrade?

 

[A9X]

If I'm reading this right, if you are upgrading speakers in a sealed cabinet, it's not advised to add a port during the upgrade?

If you want a ported cab, and the driver and box work out for it, then fine. But you need to define what you want.

 

[billfitzmaurice]

If I'm reading this right, if you are upgrading speakers in a sealed cabinet, it's not advised to add a port during the upgrade?

That depends on your definition of 'upgrade'. Drivers that are designed to operate in sealed enclosures have two characteristics, a low EBP and a high Qts. In general those characteristics are found in drivers with lower magnetic flux values, and that by and large means inexpensive drivers. More expensive 'upgrade' drivers are usually more expensive because, amongst other factors, they have higher flux values. That also equates with a higher EBP and a lower Qts, and that usually makes them poor candidates for sealed enclosures.
In short, if you don't know what you're doing, leave it alone.

 

[jz0h4d]

Simply stated it's not a very good to seal the ports in a ported cabinet.