Wobbly Woofers

[colinB]

Ive been mucking about with my speaker positioning trying to improve my imaging when all i really want to do is to listen to Cat Powers sexy tones , and i noticed my speakers wobbling like mad when cueing up. This is obviously connected to rumble on the LP but ive only just noticed it. Is this an occupational hazard of playing vinyl? Should i just ignore it and pretend it isnt there ?? Or is there some tricks of the trade which can improve the problem.

[MartinT]

It's par for the course. All vinyl is imperfect and many have small warps, let alone what happens when you're cueing up. If your system has good low frequency bandwidth then your cones will wobble all the time to some extent. You can live with it (although small speakers will have limited dynamic ability with all that extra work) or enable a rumble filter. Some phono stages obey the strict RIAA curve and feature a built-in rumble filter.

It helps if your deck is on a good isolation platform.

[John]

Get a good wall shelf and mount TT on that
Also consider some kind of isolation under the speakers might help

[Gdg]

I'm about to receive, this product (sorry, italian only):
http://www.mcmantom.com/IT/prodotti/crossover_passivi/90.20-30/OS-90.20-30.htm

Here is the main page:
http://www.mcmantom.com/IT/OnLineShopNEW/

access the product from "Crossover passivi/Filtri in Linea RCA"

I'm going to use them between the pre-phono and the ampli line-input when ripping vinyl to get rid of low frequencies under the 20 Hz.

I'm going to let you know how they work.

[Stratmangler]

Funnily enough the wobbly cone thing is exacerbated by speaker ports.
If your drivers were in a sealed box then the wobble wouldn't be as obvious.

As has already been posted, it's normal, and the better isolated your deck is the less you see of it.
A LF cutoff filter used to be standard in most Phono inputs on amplifiers in the days when vinyl was commonly used by the masses.

[colinB]

I got the Icon audio pre amp partly on the basis of it having filters for low surface noise but i never had wobble with the cambridge phono.
My deck has isonoe feet and sits on a music works Quadraspire. I might rethink my lay out with a wall shelf. It wont be easy but ive come to the opinion its best to clear the space between the speakers so i might have to have a radical change. So many expensive mistakes and wrong avenues with hi fi.

[YNWaN]

Wobbly Woofers is an interesting aspect of turntables. A great deal depends on a host of different aspects as to how pronounced this effect is. As suggested by others, the woofer damping (both electrical and mechanical makes a difference (as to how visible this quality is). Very small amounts of record (or stylus) instability can make a huge difference to this aspect. It is certainly worth trying lots of different types of isolation for the deck itself.

When I was working on the suspension of the deck I use now I discovered that; although the chassis is supported on quite resistive visco-elastic elements, the precise way in which it interfaced made a pronounced difference to woofer stability. As standard it was designed to use three hardened adjustable domed points that rested in shallow cups (attached to he top surface visco-elastic mount). When a secondary spacer was included between the cups and the adjustable points - cone wobble was significantly reduced.

[colinB]

Thats got me thinking.. The isonoes i got recently either sit on the shelf with the built in ball bearings or they can be coupled with a glass disc or sorbothane foot. I went for sorbothane because the Quad shelf buckles slightly so isnt truely flat. Sitting flat on glass/perspex has got to be very different from squidgy sorbothane so ill try them without tonight.

[colinB]

Thats got me thinking.. The isonoes i got recently either sit on the shelf with the built in ball bearings or they can be coupled with a glass disc or sorbothane foot. I went for sorbothane because the Quad shelf buckles slightly so isnt truely flat. Sitting flat on glass/perspex has got to be very different from squidgy sorbothane so ill try them without tonight.

[YNWaN]

Please do let us (me) know how you get on :).