what is subsonic filter for

The subsonic filter is designed to roll off bass frequencies below 20 Hz. Back in the good old LP days, warpage generated sonic artifacts in this frequency range.

Warped LPs played without a subsonic filter meant that some of the watts from the amplifier would be wasted amplifying the signal from the warp. The efficiency would be reduced and the clipping point affected.

Back in the 70s with the monster receivers, a warp reproduced at full power (without the filter) could easily cause the woofer material to end up on your lap :D So the subsonic filter would protect the speakers as well.

In my particular setup I have found the subsonic filter is seldom needed. I don't detect any improvement in the sound by using it. But then, virtually all my LPs are flat.

With CD the subsonic filter is not really needed, unless you listen to a lot of pipe organ recordings (at painfully loud levels).
 
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Yeah, what he said.

Give your table a very light 'tap' on the base next time you spin a lesser LP in your collection. It can also help with airborne and direct vibrations from your speakers low freq response.

Cheers,
Russ
 
Yes, you are right. The subsonic can aid in reducing airborne induced vibrations from being amplified along with the music.

One of the things that I like most about my MMF-5 table is the dual plinth construction. In my particular setup, feedback and other extraneous vibrations are a thing of the past. A far cry from my plastic direct-drive Sansui turntable back in the 1980s!
 
The best use I have found for a subsonic filter is in the reduction of "table rumble". This happens at high volume when the very low frequencies reproduced by your speakers vibrate your turntable and cause a very loud "kinda hum" in the sound. The human ear cannot hear below 25 hertz. Anything lower than that can only be felt. If your amp or receiver has a subsonic filter, I highly recomend using it. After all, why waste wattage on ultra-low frequencies that you can't even hear? :thmbsp:
 
Unless, of course, you have big ass power and like rattling stuff in the other room! :rockon:
 
crooner said:
In my particular setup I have found the subsonic filter is seldom needed. I don't detect any improvement in the sound by using it. ).


You shouldnt be able to hear any difference with a good subsonic filter. Most amps that have one cut the frequencys you cant hear anyway (below 20hz) Mine cuts at 15hz and I leave it engaged all the time. Too many people think when they cant hear a change its not working. . . Some do cut higher but most cut only below audibility. . . Use it. . . It will protect your cartridge amp and speakers.. even though you cant hear a difference.
 
subsonic filter...

...a very useful switch if you use turntables and 'ported' two way speakers :yes: ..reduces the amount of low frequency information that causes cone flap..and lets the speaker cone get on with reproducing the frequencies in the range of human hearing...
mine works at 16 hz...and seems to help the sound tighten up into focus especially on acoustic instruments :thmbsp: ..probably also saves my speaker from needing new woofers when i crank the volume up :yikes:
 
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