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Discussion in 'Amps and Cabs [BG]' started by DWBass, Jan 1, 2012.
Ports are common on the front or rear of cabs. Why not on the sides?
They'd 'look funny'.
There's no engineering reason not to put them there. As a matter of fact, I do.
Given typical box proportions, a side port could be longer than a front or rear port, making it easier to get the needed port length without being tempted to make the port too skinny.
Because it would divide ported design fans into three fanatic sections instead of two .
On Hi-Fi field the port location varies more than on the MI/PA field IME, especially on larger subs where the sub is often disguised as a table.
Depending of the machinery, front ports are often "more convenient" to make as well.
Was just a thought! I figured it could solve the old 'rear port, can't put the cab against the wall deal'! Definitely wouldn't bother me in the least if they were on the sides.
Only until one of your band mates comes along and puts his amp next to yours........
I thought you wanted to keep the port a quarter of a wavelength of the box tuning away from boundaries. It's what I've read anyway. Is that wrong?
Ha! Good one. Fortunately, I have my own space on my current gig so I won't have that issue.
that is the only reason it stopped me from doing it.
aside from the usual banter, its the real reason front ports work the best since the front contains speakers (most the time) and no bodys gonna block them, so why not put the ports there too.
That's precisely where you don't want it, as it will cause output cancellation.
Gotcha, I think. A typical bass cab, rear ported, a foot from the rear wall would be OK, stay away from a quarter of a wavelength. Confirmed?
Reckon if I make a box the ports will double as handles.
1/4 wavelength makes the cancellation. The distance between source and boundry determines what's going to get cancelled or enhanced. Mid and upper frequencies are more directional, moving forward from the cone. Below 100-150 hz or so?, they become omnidirectional so the wall behind the cab affects the sound made by the cones in front. When you get beyond a couple feet or so, the cancellation gets moved into the lower frequencies that suck the "heft" out of our rigs. This can make or break you in subwoofer placement. There you use the boundries to get more output for free, or at least not cause anything destructive.
In a bass rig in a particularly bad room, you could use the cancellation to your advantage to help eliminate boom, like setting a cab on a chair.
Measurements here. Boundary Cancellation and Room Modes
For example, raising the cab 2.8 ft. off the floor will cancel 100hz.
Side ports are fine---I'm starting to use them on really small cabs to be able to get longer ports (smaller boxes require longer ports for the same box tuning)
And how right you are and perceptive too. I never thought of that facet!
P.S. Happy New Year Sam.
Four, actually. You'd have right side versus left side proponents.
Just for giggles, my computer subwoofer is side ported.
It's called a "port" for a reason. It belongs on the left side; otherwise it would be called a "starboard".
Five - ya forgot the top!
You can definitely have the ports on the side of a bass cabinet, but I think it's a little easier to put them on the rear of the box. Euphonic Audio's Wizzy 12 M Line has a side port, but it is a Transmission Line Cabinet that needs the extra length.