Phono-pre: subsonic filter on or off ?

Marakanetz, Infra and Sub are NOT synonymous. neither are Ultra and Super.

Ever heard of super violet? SUB-Sonic has always been used for the speed of an object being lower than the speed of sound and never for UNDER-AUDIABLE, whatever that is. If you meant audio or audible, then that is not synonymous with sonic either. Sonic has to do with sound, not audibility.

Infra and ultra have always been associated with frequency, low and high, of vibration, sound and light, among others.

Perhaps this is a second language thing.

respectfully, Bob p.

Bob,

"Sub" prefix denotes "under" or "below" when attached to a word. "Sonic" means having to do with, or using, sound waves. So "subsonic" can describe something that is below sound waves, meaning you cannot hear it. Granted, "sonic" is also an adjective used to describe something that has to do with the rate at which sound travels under another meaning, and "subsonic" generally means under the speed of sound. However, before we let semantics get too much in the way, let's use common sense, shall we? Do you really think subsonic filters are designed to cut off the frequencies that travel below the speed of sound rather than frequencies that cannot be heard by the human ear but produce inaudible rumble? C'mon, you can't be serious! I don't know how fast sound waves of 20 Hz or less travel, but I do know it is generally accepted that 20 Hz is the lower limit of the human hearing. Rumble filters such as KAB are designed to suppress sound waves of frequencies under 20 Hz, meaning they suppress sound waves that cannot be heard by the human ear, but are still reproduced by the amp and the speaker and cause the woofer pumping. Not the dictionary, but the common sense in the design goal dictates it.

I had a KAB rumble filter that I could switch in and out. Woofer movement was a problem with my HW-19 an assortment of tube gear and TT positioned well away on a wall rack. I was even surprised when I had the TT sitting solidly on a brick hearth. I tried springs vs sorbothane, vs Navcom with absolutely no change. Tonearm change from Linn Basik to Audioquest PT-9 again, no change. Speakers changed from Snell Ellls to Salks TL-2s. No change. Well the KAB fixed that in a heartbeat. Never could I hear a speck of difference. I am now using a TNT Mk-3 without the filter as it doesn't need it but I would slap it back in the tape loop if those woofers started flopping around

It's clear that music is a complexed signal that has over and under tones.
Rumble or subsonic waves of a large amplitude are not safe for the listener and can cause heart problem if not collapsing and should be voided.
I've always thought that it's part of RIAA standards to have subsonic filters as a matter of fact since becides EMI causing rumble there are record or pressing imperfections that also can take part especially if played at the high volumes.