Several years ago I experimented with sealed and ported versions of a monitor speaker designed to be used with a sub. In other words, I was focusing on the midrange performance only; the low end didn't matter. I arranged a simple blind listening test (double-blind isn't necessary; it's okay if I know which speaker is playing). To my surprise, the ported speaker was consistently judged to have more natural-sounding midrange. This wasn't what I expected. Rear-firing port, flared inside and out.
Turning now to the low end, I've worked with both types (as well as other technologies) in the course of subwoofer development. It's all just too complicated for me to make a blanket statement that one type is better than the other in the low end. So many variables at play - room size and anticipated speaker placement, enclosure size and efficiency constraints, SPL and low-end extension requirements, whether or not EQ was available, and last but not least, budget. In the end I decided to offer both sealed and ported subs, and try to match them to the specific situation.
The way I sometimes tune a vented bass system is somewhat counter-intuitive; I'll tune it a lot lower than normal, so that it has a slower rolloff than even a very low-Q sealed box across most of the bass spectrum. Of course the rolloff accelerates rapidly below the tuning frequency, but if it's low enough, who cares. If possible, I want the tuning frequency below the claimed passband of the system. Here's why: As notes close to the tuning frequency decay, their energy spectrum actually shifts *towards* the tuning frequency. Obviously that's not a good thing for pitch definition. But this detimental effect is not inevitable! If we design the system so that the tuning frequency is low enough we can minimize this effect, and therefore imo a good vented box can have pitch definition just as good as a good sealed box.
Clio9 mentions the user-adjustable tuning that I incorporate into many of my designs, and I'd say that roughly half of my customers have ended up using a different tuning frequency from what the speakers were shipped with. Either I'm a remarkably lousy designer, or there's enough variation from one system/room situation to another that some ability to tailor the low end is often useful. In many cases, it's possible to improvise a way to lower the tuning frequency of a vented system. In my opinion, this is one advantage of a vented system over a sealed one.
Duke
dealer/manufacturer/possible lousy designer
Turning now to the low end, I've worked with both types (as well as other technologies) in the course of subwoofer development. It's all just too complicated for me to make a blanket statement that one type is better than the other in the low end. So many variables at play - room size and anticipated speaker placement, enclosure size and efficiency constraints, SPL and low-end extension requirements, whether or not EQ was available, and last but not least, budget. In the end I decided to offer both sealed and ported subs, and try to match them to the specific situation.
The way I sometimes tune a vented bass system is somewhat counter-intuitive; I'll tune it a lot lower than normal, so that it has a slower rolloff than even a very low-Q sealed box across most of the bass spectrum. Of course the rolloff accelerates rapidly below the tuning frequency, but if it's low enough, who cares. If possible, I want the tuning frequency below the claimed passband of the system. Here's why: As notes close to the tuning frequency decay, their energy spectrum actually shifts *towards* the tuning frequency. Obviously that's not a good thing for pitch definition. But this detimental effect is not inevitable! If we design the system so that the tuning frequency is low enough we can minimize this effect, and therefore imo a good vented box can have pitch definition just as good as a good sealed box.
Clio9 mentions the user-adjustable tuning that I incorporate into many of my designs, and I'd say that roughly half of my customers have ended up using a different tuning frequency from what the speakers were shipped with. Either I'm a remarkably lousy designer, or there's enough variation from one system/room situation to another that some ability to tailor the low end is often useful. In many cases, it's possible to improvise a way to lower the tuning frequency of a vented system. In my opinion, this is one advantage of a vented system over a sealed one.
Duke
dealer/manufacturer/possible lousy designer