My Findings...

[Miguels]

i 45d my corners and run my hifonics to clipping.. its so awesome

[ParDeus]

I hate that people keep talking about the airflow in an enclosure, more specifically through corners. If it was going in a single direction the subjective term air flow could be used, but that's not the case at all. Air is going back and forth continually at high rates. 45s might help...if instead of subwoofers in the cutouts they were fans.

So if air is going both ways it's not airflow??? I don't get that.

Even when air is traveling "one" direction, such as a leaf blower, it travels both ways. Again, an oversimplification, but the analogy stands.

[bbeljefe]

Some very interesting testing and I'm tuned in for more but, I have a few thoughts to share...

In audio, we aren't really concerned with air flow. That may sound counterintuitive but let's face it, we aren't metering air flow in the lanes, we're metering sound pressure. And if improving air flow makes sound pressure higher, that's what we need to do but... if x amount of reduced air flow increases sound pressure, then that's what we need to do. In simple terms, air flow is a means to an end.

There has been some empirical testing which shows that wave guides (when placed properly) increase sound pressure. So while the testing you're doing is awesome we need to keep in mind the end goal of this testing, which is sound pressure, not air flow.

Correct me if I'm wrong but, perfect air flow in a vented enclosure would actually cause cancellation at and around tuning. The reason being the same reason that free air causes cancellation. The idea of a vent is to slow the air down enough (delay) that the back wave of the driver is just enough out of phase with the front wave that they increase sound pressure, so even though it may not make sense, turbulence within the vent could actually help.

[TeamHT]

Vibration isn't exactly air flow. Its also why I said the subjective term. At the most basic, aerodynamics isn't made for multiple direction airflow pushing and pulling at the same time, continually, every second. Its why something that would increase efficiency in airflow doesn't exactly work in an enclosure. People will build what they want, regardless of how it is explained and sometimes the 45s could be structural.

I would love to hear more on your opinion of aeroports

[Karkov]

I would love to hear more on your opinion of aeroports

This ^^

[ParDeus]

The above is the kind of feed back I want, thanks HT and bbe. I'll admit to knowing jack shit about acoustics. Can you guys give me some ideas to incorporate into the testing?

I should have said an aeroport is not very efficient from an airflow persepctive. With that said, I've tested an aeroport with a convergent/divergent "fin" at the first third, then halfway, and then just before the terminus. Db in the port (measured .5" from the end) increased .3 db when place near the exit. It increased .1 db in the middle, and dropped .1 when placed at the first 1/3rd.

I'm not too awfuly familiar with the equipment my friend used to measure the frequency change, or if our controls were of best practice, but he said the change equated to less than .7hz through the test. I'm sure you guys can give me a better idea of the acoustical implications of that test.

[ParDeus]

When I get back home I'll try to draw out the "fin" in which I referenced. Anything like sketch up available for Android tablets?

[bbeljefe]

I wouldn't think that 7/10 of a Hertz would negate your testing. At least not with respect to human hearing.

I'm also interested to find out what you found to increase air flow (other than 45° wave guides) and more importantly, what effect that increased air flow had on sound pressure.

[TeamHT]

Props for an awesome new member

[MACnonsence6]

this is why i planned to use bondo and smooth my corners round vs 45s it made more sence that air would move easier that way. i believe my idea would also form a 90 not 100% though