Dukk

In identical boxes tuned to the same frequency, there is a plainly audible difference between a regular round vent (with neatly 1/4" radiused edges) and an aeroport. It was quite surprising really.

xxPunk0Ramaxx

The decreased port speed that a flared port provides alone is enough of a reason to use one, in my opinion. There is a lot of empirical data suggesting that a round flared port is truly the most efficient and aerodynamic port available.

Haunz, are you an AES member? There are a couple of good AES Journals through which I can demonstrate my point.

1LoudScort00

iTrader: (2)

thats why i said differant applications lol

Haunz

iTrader: (3)

the only way there could be an audible difference is if the tuning was different, or if there was more then 1db difference in output... (which would be rediculous... )

I have personally never heard a difference moving from an aeroport to a regular port or vica versa....


There may be a slight difference in efficency with an aero port but its going to be near zero in any box I ever build.... If port velocity and losses which cause the dreaded port whistle are going to be an issue using a wider port is an immediate solution....


That said I will gladly read any article you want to send me Punk0Rama....

Dukk

Haunz, I will flatly suggest that you have never auditioned, side by side, two identical boxes tuned to the same frequency with the same driver, one with a regular round vent, one with an aeroport style flared vent.

I have. The difference is obvious.

Back when Korbon Trading still held it's Audio Forums, the one year Wayne Harris taught a course on box design and part of his presentation included an array of plexiglass enclosures (sealed, vented, bandpass, vented bandpass) and the vented enclosures included examples of both standard vents and aeroports. As I stated, the difference was obvious to everyone in attendance.

The difference between experience and simple speculation..

Haunz

iTrader: (3)

ahh you would be wrong there dukk... and I will maintain that the only way it could sound different is if in fact the tuning was different....


as I said a regular port that is the same length as a aero port will not be tuned to the same frequency........... and that must be the difference you speak of; and is probably what was being demonstrated....


of course unless it is was a double blind ABX test your comments wouldn't be valid anyway.....

Dukk

Sooooo that's a NO to real world practical experience then? I thought as much.

From 20 feet away I could not tell which box was playing as the two were compared so it was as good as an ABX test. Closer examination confirmed the flared vent was the superior performer.

Let me try to simple this down for you.

Know anyone with a Clarinet? Take the bell off the end and replace it with a piece of straight tube the same length. Think it will sound the same? The answer is no. Why?

I find your stance on this subject interesting since you tend to promote yourself as learned in advanced box design, including horn theory. I guess I was indeed wrong about something.

xxPunk0Ramaxx

Here you are both agreeing that flared port and straight port of the same length will not be the same, and you are both correct, because a flared port of the same length would have a higher Fb.

In terms of audibility, I have to argue that it would depend on the circumstances. I stand by my statement that a flared port is more efficient and aerodynamic than a straight port, but if your port velocity is below 15m/s to begin with, you would be hard pressed to notice a difference.

Now if you have designed an enclosure where port velocity is, say, 40m/s (like a large number of 4th and 6th order bp's out there), then using a flared port is a great idea. Port velocity would drop to ~24m/s (again, depending on the radius and length of the flare).

I see both points and I think both are accurate, but it comes down to audibility in specific situations.

Dukk

The enclosures I spoke of were tuned to the same frequency. The vents were not the same physical length - that was another of Haunz's random speculations.

15m/s is a nice goal for vent velocity but that is often exceeded in our hobby. I often see designs that exceed 10% of mach.

xxPunk0Ramaxx

My apologies then. I must have misread your Clarinet analogy.