Do logitech z-5500 have port noise problem

[nik234]

I own megaworks 550 and although i am generally satisfied i face some problems with the sub. Specifically, during bass heavy movie parts i hear excessive(annoying) port noise. I'm wondering if logitech 5500 have the same problem, because i want to upgrade to a system with no serious drawbacks.

 

[ichigo]

I believe the problem is more in the area of THD spikes. Like, spikes that are louder than the actual musical bass. One of the many reasons neighbors down the street "complain" so much about computer subs at normal listening levels (mostly Logitech in general). You don't usually have this problem with better, more linear subs, even at very high output levels.

One of the ways to lessen the THD spikes are to block to port, and effectively reduce extension (and thus no longer hitting notes that it shouldn't be as loudly as before).

 

[nik234]

When i say port noise i mean blowing and sucking sounds(not bad quality bass) at 39 to 42Khz.
By the way what can you do to effectively close the port?

 

[tbewick]

That's the first time I'm ever heard of a problem like that! You have to remember that during loud peaks in a Dolby Digital/DTS soundtrack, the subwoofer (in a THX 80 Hz crossover set up) may have to reproduce up to 120 dB, which is very loud and demanding.

I'd suggest introducing a low-bass roll-off, like the one used in the THX boundary gain compensation filter. I have a THX Altec Lansing system, and I find that this works reasonably well. In an attempt to clean up the bass response, I did once try blocking up the ports on the subwoofer. It wasn't very effective so I leave the ports unblocked.

I don't have a THX sound card so I don't have the THX boundary gain compensation option. I use a simple equaliser on my sound card to introduce a more severe roll-off than the THX filter, -3 dB at 125 Hz, -6 dB at 63 Hz, and -8 dB at 31 Hz. I don't watch many films on my computer, but I'm pleased with the results when listening to music.

Another thing you could do is to lower the low frequency effects channel volume.

 

[Sheep]

These systems don't fart.

You will hear the driver die, literally say "Holly ****, I'm dying!" Before you hear any PN.

You can listen to them at FS or BB or CC and see if you like it.

SheepStar

 

[ichigo]

Socks or cotton are common things one might use to block ports.

 

[nik234]

The problem is only with frequencies between 38 and 43 Hz(the frequencies that the port amplifies) and at not extremely high volumes. My card is an xfi xtreme music.
What does fs,cc and bb mean?

 

[GarrettMaster1]

The only thing you might experience with the bass is what some call "boomy" bass. I have experienced it a little but the sub's excellent response was enough to forget about it

 

[Sheep]

The port amplifiy's all the frequency's. Its TUNED to 45Hz or so, so it will peak in response there. You might wanna check and make sure its not actually something rattling...

FS= Futureshop (if in Canada)
BB= BesBuy (If they have a demo setup)
CC= Circut City

SheepStar