Simple passive HPF for 2 channel fronts

[qguy]

I just installed a 2 channel system with a Integrated amp , 2 small satellites and a subwoofer in my bedroom TV, For music everything is fine , its when i watch some heavy action movies that I noticed that the 5.5 inch woofer in the small starts to blurt our weird sounds. I reckon I need to remove 80 HZ below. How do I do this. I have seen tweeters protected with a capacitor directly driven by an amp. Can I do the same thing ? What value of capacitor do I need to filter 80 hz below.

Thanks

[David Gatti]

You're on the right track. I would recommend a line-level high pass filter.
Something like these from FMod if you're system allows it.

http://store.hlabs.com/pk4/store.pl?view_product=10

If you're satellites are ported you could try sealing them with a sock in the port to reduce cone excursion.

[Loren42]

Originally Posted by David Gatti

You're on the right track. I would recommend a line-level high pass filter.
Something like these from FMod if you're system allows it.

FMOD (Filter Module) High Pass RCA Level Crossover

If you're satellites are ported you could try sealing them with a sock in the port to reduce cone excursion.

+1

Passive components for that low of a roll off will be big, expensive, and tend to compromise the sound.

[rabbitz]

Have a look at your sub amp as it may have a HP out (80-130Hz 6dB filter) for satellite speakers. Usually it is done via high level (speaker line) and not line level (RCA). This means the speaker wire from the integrated amp runs to the sub amp and then speaker wires to the satellite.

These usually use a 220uF cap in series to the output to the satellite speaker with a 8R nom impedance (see pic). For 4R nom speakers it would need to be 470uF.

You didn't say what your amp is, but if it's a Home Theatre amp you can set front speakers to small which redirects all bass to the LFE channel. If it's a stereo amp, then you can't do this.

[Kjeldsen]

80 Hz might not be low enough. There's a lot of energy between 80 - 200 Hz. A surround amplifier is probably the best solution, since all you need is build in.

The cap will help, but it's only a 6 dB slope, so lots of low freq will still come to the small 5½ inch woofer.

A 220- 440 uF bipolar electrolytic cap is not that expensive (and not very good audio quality either). You will see a cap like this on many small car audio speakers as well.

[qguy]

I am using an Integrated AMP and not an AVR.

I will try running the speakers via the speaker out from the subwoofer. The subwoofer is connected via speaker level.

thanks