Axiom Home Page Forums General Discussion Home Theater VP160 Concept Discussion

Just to be clear those discussions on ported vs sealed did not discuss extension but rather general notions about "musicality", "tightness" and "quickness" and other misused terms about subwoofers and the idea that is spread around that sealed subwoofers are always better than ported subwoofers for music listening. It is not necessarily the case.

I hope this clarifies things.

Ok, well while we are clarifying things, let's make it clear once and for all just what the differences are.

I for one had always had the understanding that ported designs were more efficient in producing lower bass, and moving more air because they made use of both the air being moved from the front of the woofer cone, as well as the air being moved from the back of the woofer cone via the port. And that sealed designs were more efficient in producing clearer bass due to the absence of 'port noise' that plague ported designs.

Now those were the views I held previous to becoming a member here on AxiomAudio.com. Since then I've come to the understanding that the end result in performance has nothing to do with the box design, only in the enginering of the equipment incorporated in such designs. So this is the information I've been passing along to others. Somewhere in the process I completely missed anyone explaining that ported designs have lower bass extension. And I've read pretty much every thread in this forum over the past year and a half. So if I missed it, I'm sure there are many other's who missed that as well.

This is in fact the 1st time I've heard it acknowledged that there are any advantages and/or disadvantages to the box design. That's not to say it has never been acknowledged before, just that this is the 1st time I can remember seeing it. So then what is being explained to us now is that ported box's hit lower bass notes? Is that what is meant by 'bass extension'? Please excuse my ignorance, I'm just tryng to get a clear picture of the differences between the two. And if ported box's produce greater bass extension, then what exactly is a sealed box's inherent characteristic?

The information all seems so contradictory sometimes. For instance my EP800 is sealed, yet produces lower bass extension than the ported EP600. Does this mean that a ported EP800 would have even greater bass extention? And if so, then what was the reason to use a sealed box?

Enquiring minds want to know. Up until now I thought I had finally come to understand that when a newbie popped up on here claiming, "I prefer ported box's over sealed box's", that he didn't know what he was talking about. Now it seems entirely possible that he prefers the greater bass extention of a ported box.

Clarifying the differences between these two designs would save a lot of confusion for me personally, as well as many, many others I'm sure.

The EP800 has lower bass extension than the EP600 because the EP800 has two drivers and therefore double (or 113.4 sq in) more driver surface area. This would be equivalent to a single 17" driver.

My, admittedly limited, understanding of ported speakers vs sealed(not referring to subwoofers, but woofers/mids) is that the ported speaker reaches lower as has been noted, and a sealed speaker gets it's "tighter" or quicker(accurate?) reputation from the fact that it is always supported by the air pressure within the box which causes the woofer to return to it's static position more quickly.

Also a sealed sub can still produce the same bass extension given the proper driver size and a HUGE amount of wattage behind it. A ported design is just easier to run and design to achieve lower bass extension or high output, also a ported design allows the user to tweak the port opening, ala my PB13, for more output or lower extension.

Size of the enclosure matters, too.

Look, there is A LOT of science in loudspeaker design, and you can't just reduce it to one factor (cabinet design) and generalize to "all".

Not ALL ported designs have greater bass extension than similarly sized sealed enclosures. There are dozens of other factors at play.

In addition to the excellent points made by Jay, Steve and Adrian, you also have to consider potential tradeoffs relative to SPL v. extension.

If loudspeaker design was "easy", people wouldn't get paid to do it or write books about it, or surf the internet all day.

That's pretty much what I figured. But where I start to lose a clear understanding of the way things work is, if they're using 600 watts to move the one woofer in the EP600 in a ported design, which is more efficient than a sealed box, then I would have thought the EP800, which uses a less efficient design, would require more than 400 watts per speaker to even get close to the output of the 600.

I was very surprised when the EP800 came out that it was only their second sealed subwoofer. I'm very interested to hear, from one of Axioms designers, why they chose to go with a sealed box for the 800 instead of porting it like most of their subs, which produces greater bass extension. The way I'm understanding things now it just seems like it would have been easier to achieve their goal performance with a ported box.

If in fact a ported design holds an advantage in the area of bass extension, then I'm curious why they would take what seems like 'the harder road' to getting the EP800 to hit those awesome low bass notes that it does. And why it doesn't require gobbs more power than it does to perform the way it performs.

I'm certainly not trying to be difficult here, I'm just really mixed up in the reasonings behind all these decissions because my understanding of the differences between the two designs is very fuzzy. I've thrown out all the information I had on the subject growing up because it seems it was all based on myths. But so far, all attempts I've made searching for the differences via the internet seem to conflict with the information I've gotten here.

Which is why I'd love to hear it from the horses mouth. What advantage did the sealed box used with the EP800 have?

Micah,

This excellent link below that I have posted many of times will explain all the details you want to know about subwoofers and how they behave. While it is long and can get quite technical bear with it. In the end you will be able to take out of it a general answer to all of your questions you are seeking.

http://www.audiopulse.com/know-how/subwoofer-driver-guide/myths-about-subwoofers/

Mr. Link comes to the rescue again.

Thanks for the clarification Micah. I understand now where you are coming from.

I was thinking more of the quality of sound, and there, two similarly well engineered subs or speakers, one ported and one sealed, will not sound any different.

If you look at a frequency response graph for a sealed vs ported design using the same driver and without and equalization/dsp you will immediately see the difference between the two designs. The seales driver will roll off more gently as frequency drops. The ported design will 'fall off a cliff' below port tuning.

From there, the driver design and the goals of the designer dictate which direction to go.

As a general rule, with a sealed sub, you trade off size for efficiency/power. This is the main reason sealed subs remain popular. Not everyone wants a large box in their livingroom.

Hey Beavis, Tom said size matters, he he he he he, fire fire.