Does plugging speaker port also affect midrange/treble?

[Acceptable]

I have a pair of Polk TSi100 with SMHL SA-50 in a 12 x 12 feet dorm room with hard surfaces. The speakers are rear-ported and are about 4-5" away from the rear wall. I can't move them further away due to room restraints.

Although I'm not an expert, I feel like the bass is a bit bloated/overwhelming. I tried stuffing the rear ports with rolled up socks per suggestions on this forum, and it made a noticeable difference in bring the bass down to a comfortable level.

However, at the same time, I also feel that it has reduced the midrange and treble a bit. Music sounds more flat and less three dimensional and no longer has that immersive quality that the speakers originally had.

Is this just a matter of me not being accustomed to the new sound? Or does stuffing the rear ports also affected high frequencies?

As an alternative, would it help if I left the rear ports open, but instead glued a piece of foam to the rear wall directly where the rear ports blast onto?

 

[JMJVK]

It depends on the cabinet's design.

 

[Seth=L]

I don't have experience with your speakers, but I do have experience plugging the ports on my speakers. My Infinity IL10 bookshelf speakers are similar in concept, they're a 2 way speaker with a rear port and much like the Polks you have the Infinitys sound bloated when placed next to the wall with an open port. By plugging the ports I get a far more balanced sound from the speakers. I found the midrange to be more natural to my ear with the ports plugged.

Now something to consider when plugging the port. The efficiency of the speaker system itself is compromised. In order to get the same output you'll need more power. You will lose bass extension. Some ported speakers use the open vent as a way to cool the driver's voice coils, specifically the tweeter. Some tweeters even require heatsinks mounted on the back in order to displace heat.

I'm not implying that plugging the port would damage the speaker, but depending on how loud and long you play them the tweeter specifically may become fatiguing depending on the design. The heat in the voice coil causes more resistance and less stability in the driver and can cause the driver to sound more "harsh". And because of the reduction in low -mid frequencies the tweeter's output in correlation to the midwoofer is now accentuated. Combined with added harshness the speaker becomes more fatiguing. This is probably an extreme, but it's possible depending on your listening habits.

 

[markw]

Keep in mind that in your two way system with a 5" "woofer", that "woofer" is designed to produce all the midrange band and and a little bass as well. I cannot see a crossover point listed for your speaker. to be honest, that speaker doesn't really produce bass, but upper bass at best and it tends to have a boost in that area in order to give the illusion of real bass. That may be your real complaint.

The cabinet volume and ports affect the deepest lows it can reproduce only and anything above that should not be affected but, then again, your woofer is actually a midrange driver that produces a little bass to go with it.

As for the sock, it does change the overall sound of the woofer, and perhaps the midrange as well, thereby affecting the entire balance of the system as a whole. If the woofer produced more midrange than you think, that may be affected as well.

Many tweeters and separate midranges are sealed back designs so the cabinet volume would have no affect on them.

As for any thermal damage, don't worry about it. If you overdrive it, you'll hear sounds of strain long before anything happens.

No offense intended, but the sock idea works best when dealing with somewhat larger systems where real bass is part of the equation. I honestly think it's the inherent nature of your speaker that bugs you.

 

[zieglj01]

As an alternative, would it help if I left the rear ports open, but instead glued a piece of foam to the rear wall directly where the rear ports blast onto?

Put some foam behind the wall - leave 2 inches from the foam to
the back port. Test it before you glue it.
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I would not use socks for Polk speakers. If I did plug the port, I would
not completely plug it - I would us poly-fiberfill, so that some air could
still leak through the fiber in the port.

Cheap Polk speakers tend to have the boomy nature to begin with.
Plus, not a lot of detail in the midrange to begin with.

Do the best you can at this time.

 

[zieglj01]

erased

 

[Acceptable]

Thanks for the tips guys.

For future reference, what bookshelves speakers would you guys recommend for <$200 that are good for music listening? Should I upgrade the amp first? Would active speakers like the Audioengine A5 be an upgrade?

 

[BoredSysAdmin]

Wave Crest hvl1 or philharmonic audio AA bookshelves

 

[zieglj01]

For future reference, what bookshelves speakers would you guys recommend for <$200 that are good for music listening? Should I upgrade the amp first? Would active speakers like the Audioengine A5 be an upgrade?

Your amp is fine for now

Also the Philharmonic AA is a serious good option - and not easy to beat
even with more expensive speakers.
They have good detail and definition and some nice, tight and controlled
bass. They would be an ear opener compared to what you have now.
http://philharmonicaudio.com/aa.html