New Posts New Posts RSS Feed - Rumble (again...)
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Welcome to the Graham Slee Audio Products Owners Forum

 

Open to all owners plus those contemplating the purchase of a Graham Slee HiFi System Components audio product and wishing to use this forum's loaner program: join here (Rules on posting can be found here)

This website along with trade marks Graham Slee and HiFi System Components are owned by Cadman Enterprises Ltd


Rumble (again...)

 Post Reply Post Reply
Author
Graham Slee View Drop Down
Admin Group
Admin Group
Avatar
Retired

Joined: 11 Jan 2008
Location: South Yorkshire
Status: Offline
Points: 16298
Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Topic: Rumble (again...)
    Posted: 12 Nov 2017 at 5:12pm


Year upon year customers question me about rumble filters on my phono stages.

Actually there is one, and that can be seen from a frequency plot. However, for correct RIAA reproduction I will not compromise the bass response - I will not apply additional bass cut which attenuates, and also damagingly places the bass out of phase with the rest of the music.

However, there is cut below 20Hz but it is not a steep cut - it is a natural roll-off. A rumble filter has a much sharper cut, and a sharp cut-off filter has ripple which means the filter peaks just where it does its worse to the bass.

Most of the time there is no turntable rumble - a noise caused by the platter bearings, or even motor noise (in which case the user should treat the cause and not the symptom) - but the natural occurrence of sub-sonic fluctuations due to warps, eccentricity, and arm/cartridge incompatibility.

These show themselves as cone flap, which is simply high compliance cones responding to the signal as amplified due to the above.

I'm not a magician. I can't remove this and still keep the bass the customer wants. Show me somebody who can! And I'll show you a manipulator... (I resisted using the word liar)

A filter can be arranged to mix the bass below 300Hz in a cross-feed circuit which will sometimes fix the "problem" (I personally don't see it as a problem).

Purveyors of this solution say that bass below 300Hz is non-directional. They must have different hearing to me, or perhaps I'm from a different planet??

A good old low compliance bass driver wouldn't cone flap, but hey! That's not hi-fi...

The problem is in the marketing. Vinyl is being marketed all wrong. True, it gets more customers, but it gets customers who simply don't understand it. I'd rather have fewer customers who understand it than more customers who have to ask questions which simply weren't an issue back in the day.

That none should be able to buy or sell without a smartphone and the knowledge in how to use apps
Back to Top
morris_minor View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 27 Mar 2012
Location: Surrey
Status: Offline
Points: 6015
Post Options Post Options   Thanks (0) Thanks(0)   Quote morris_minor Quote  Post ReplyReply Direct Link To This Post Posted: 13 Nov 2017 at 9:01am
Back in the mists of time I had an integrated amp with a rumble filter. I could never hear any difference with it switched in or out. Which either meant my speakers or headphones couldn't reproduce low frequencies or the switch had no circuit behind it. Or of course that rumble just wasn't a problem. 
Bob

Majestic DAC/pre-amp
Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V
Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50
2 x Proprius + Spatia/Spatia Links
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.105 seconds.