Townshend Pods under TT Don’t Do

I know this is an old thread, but I’ve gone through my own trials on this issue, in a small room system with springy floor.

A properly tuned spring suspension is still the BEST affordable TT isolation in this hobby, by far. But whether it’s by SOTA (built-in), Townshend (external platform), or another maker - the key to successful deployment: don’t let the springs get "excited" (i.e. set in motion). Bad things happen, because this in turn can cause the cartridge suspension to get excited - and then, either your woofers will try to escape their cabinets, and/or you’ll get nasty skips and POPs.

So what excites the suspension? Any "event" that causes a displacement. If you’re on a flimsy floor, footsteps near the table are the most common cause. But even enough low frequency feedback from nearby loud speakers / subwoofers could also cause it.

The key problem is that we audiophiles LOVE getting those freestanding "tower" style racks, and then plopping a nice heavy turntable atop it. It looks cool, and it’s functional to us. We like the tower tall enough so our old backs don’t have to bend over. Unfortunately, this is literally the WORST possible turntable support, and a great example of us audiophiles shooting ourselves in the foot. In such a setup, the turntable is cantilevered out into space, and any disruption to the nearby flooring will effect a LARGE displacement unto it. This excites the spring-on-mass resonant frequency suspension, and bad stuff happens.

Expensive high-end racks are typically more rigid with a wider footprint, which honestly helps a lot (but probably not enough proportional to the $$$$ spent on HRS / CMS / SRA / etc) - but often does not fully solve the problem. Adding mass without simultaneously and proportionally increasing rack rigidity does not help, and in fact quite often makes the problem worse! So don’t bother filling your rack with sand/shot. What you SHOULD do, is brace the rack to limit its "cantilever" effect. Easiest is to just push it back up against a strong wall. I found a 2’x2’x2" foam Auralex tile worked great as a shim here, to ensure good contact. You may scoff at the inconvenience this causes for cable routing, but unless you’re on concrete slab - it’s worth it. Even a cheap rack can work great like this! My crappy $600 Lovan performs just as well as the $6K CMS now - and the CMS also was not usable in this room without wall bracing.

One last point that bears repeating - this is Physics 101, but DO NOT EVER stack spring atop springs (e.g. a SOTA on a Townshend platform). Bad things happen.

TLDR; if you find your table on springs is sensitive to footsteps, your rack needs help. Try pushing it up against a wall for starters.

Hmmm, I quickly scanned this thread and did not see the discussion about suspended floors.

Turntables have been in use for well over a hundred year. Suspended floors as well. Turntables that are placed in rooms with suspended floors should be placed on wall mounted shelves… this isolates them from problems associated with the suspended floors like footfalls. This has been the solution for many - many decades. Internal turntable isolation and under to isolation is not designed to deal with the displacements and amplitudes created by suspended floors. They are designed for much lower amplitude higher frequency vibration associated with the turntable itself.

Any discussion of vibration control of turntables with suspended floors should begin once the table is located on a shelf.

@ghdprentice: Let me add that when going the wall mount route, if possible do so on an outer wall. If that is not possible, on a load bearing inner wall.

Let me add that US wood-framed homes are amplifiers of vibrations and hopeless for turntables, and the basement floor is the only place worth a damn. Second to that is slab or first floor suspended floors with reinforcement piers sitting on basement concrete.

An old technique for suspended floors is to install a jack directly under the location of the turntable, applying just enough pressure to stabilize the floor. That assumes the area under the floor is just a crawl space, not a basement. In the case of a basement, install a brace running from the floor of the basement up to the listening room floor, where the jack may be installed.