Axiom Home Page Forums General Discussion Advice from Axiom Owners Does anyone plug the ports on their m22's, etc.?

Just wondering, I recently sold my subwoofer and have been listening without it. I stuck some hand towels in the ports of my m22's and kind of like the sound. Granted I haven't listened to much yet, but the vocals sound more defined and clear. Maybe this is due only to the reduced extension, but I don't know. All the other speakers are sealed, why not the m22's to match? I wonder if I could measure the frequency response of the now sealed m22's and figure out a good subwoofer to complement.... I have way too much fun with this kind of stuff!

Andrew

How close are the ports to the walls? What you've done by stuffing the ports is effectively reduce the low end output (dB), as opposed to the extension (Hz), of the speakers. It's kinda like a tone control and, by stuffing the ports, you've turned down the "Bass." The closer the ports to the wall the stronger the bass response (can be muddy). Move them away from the walls, and it will be reduced.

Speakers tend to perform as intended when they have some space around them. Think of it as having enough room to stretch out and "do their thing."

See this pic of BrotherBob's terrific room and you'll see what I mean. Also, notice the bass traps (tall black thingys in the corners). They help reduce the very phenomenon we're talking about, i.e. increased bass response from nearby surfaces.

The point of this type of speaker design is to allow low bass to filter into the room. By blocking this port, as Jack as mentioned, you would be altering the whole purpose of a lot of research and design by the engineers at Axiom and other companies that use this concept.

Most likely if you play with different positions you'll find the same results as blocking the bass from filtering into the room.

But if you prefer it, by all means go for it.

Man, everytime someone links to BrotherBob's room, I fall in love all over again...

Imagine how much happier BrotherBob would be if he had a basement ?

Zucchinis work rather well in lieu of a towel.

You're right, the zuccini's sounded great, but my famous spicy chili was REALLY awesome!

They are about 1.5 ft from the side wall and 3 ft from the back wall. There is a 2' x 4' x 2" absorption panel in each corner.

I believe a port does more than simply add low frequency volume. Isn't it a compromise between low frequency output and distortion (in the form of group/phase delay) near the cut-off frequency? I suspect the response would be better if I unplug the port and just set the HP crossover above the point that the speaker naturally rolls off at.

Cav, our member BigJohn was an expert on plugging the ports, but he hasn't been around recently and I don't recall that he discussed the sonic effects much.

You might be interested in studying Mark Sanfilipo's article "Five Audio Myths Dispelled" published in Audioholics, especially part 4. which examines the difference between ported and closed speakers. The point is that the port, other factors being equal, extends the low frequency limit but doesn't increase efficiency.