Naim speakers on suspended plinths with NACA5 cable

Posted by: nicetone on 15 January 2017

I mean the Allae, SL2, and Ovator, all of which have the plinth suspension, to help optimise performance.

When recently unplugging NACA5 cable from my Allaes, and noting the usual stiffness, it suddenly occurred to me to ask whether NACA5 could be interfering with the suspension. Thinking, could it be similar to the effect on an LP12 suspension of an arm cable that isn’t correctly dressed?

I won’t be losing any sleep over this, and I’m not looking to stir anything up, but the question interests me.

The suspension is presumably for micro-vibration? I take great care to get the Allae set up right, as per past very helpful posts by Richard Dane. I use a spirit level on the front and sides when adjusting the spikes, and ensure that the speaker has the prescribed fore and aft rocking on the suspension while not moving from side to side. In use, I never see the speakers moving on the suspension, so any movement has to be imperceptible. In which case, I ask myself, does the stiffness of NACA5 work against it? I don’t see how NACA5 could be dressed or shaped (using hairdryer) to avoid a rigid coupling from the speakers to the floor at some point. Even if a length of cable was to be run before it touched the floor, the stiffness and weight would still appear to be an issue, acting against any movement of the speaker on the suspension. Neither would cable supports, as I far as I can see, provide a solution.

I’m thinking primarily of the Allae, but would there also be an issue with SL2 and Ovators using NACA5? Also, if the suspension is in fact for micro vibration, would there be an issue with other cables. From the old QED 79 strand to the Super Lumina, most have a weight and stiffness that I would imagine could affect the suspension dealing with micro vibration, no? (By the way, I wouldn’t look to Super Lumina as any solution, given that for the cost I could get a new pair of speakers or a newer car!)

Anyway, that’s my question. I’d very be interested in any light Richard might be able to shine on it. I appreciate that I could be way off the mark, in which case please be gentle!

Thanks.          

Posted on: 15 January 2017 by Richard Dane

Nicetone,  I'm no expert here - it's a question probably best addressed by the designer, Roy George - however, as all these were designed with NACA5 in place, I'd imagine it's use has minimal deleterious impact on the operation of the sprung base.

Posted on: 15 January 2017 by hungryhalibut

There are things to worry about and there are things not to worry about. This is one of the latter. 

Posted on: 15 January 2017 by Adam Zielinski

Sockets on Ovators S400s are isolated by themselves, to try to prevent microphonic vibrations entering the speaker enclosures.

if you use Ovator plugs with NACA5 all should be well. At least I do and my Ovators remain rock solid

Posted on: 15 January 2017 by yeti42

Is SL speaker cable decoupled in the boxes near the ends? We have decoupled power cables and interconnects and I think decoupled speaker cable would follow from the same logic, these all postdate SL2s though.

The crossover mounting screws are reckoned to be best left a little loose on allaes etc and letting NACA5 touch the wall or speaker cabinet can be heard and is best avoided, 

Posted on: 15 January 2017 by hungryhalibut

No, SL cables are not decoupled in the boxes. The box at the amplifier end contains a resistor and the box at the speaker end is empty. The plugs are flexible though, which I imagine is how the decoupling is done. If you rap the front of a properly set up SL2 with your knuckles you can see it oscillate, and so long as the cables hang free this won't be affected. 

Posted on: 16 January 2017 by tonym

I've always split the first few inches of my NACA5 for this very reason. It makes this part of the cable much more flexible.

Posted on: 16 January 2017 by sheffieldgraham

Posted this sometime ago. Plinths were to avoid vibration through my suspended floor and the crossovers. They do suspend the NACA5 from the speaker/suspended base. Maybe not to everybody's taste but it worked for me. Scroll down the post for pics.

https://forums.naimaudio.com/to...speakercrossover-mod

Posted on: 17 January 2017 by nicetone

Thanks for the interest guys.

TonyM – thanks, a simple but smart idea (now why didn’t I think of that?!).

sheffieldgraham – I’ve seen your posts on your decoupled crossover before. It looks good to me and those pictures are worth a regular airing, either as a reminder, or for people who haven’t seen them before. 

Anyway, I thought it might be an interesting ask, but I think that’s going to be all from me on this one.

As an aside, and just idle thoughts, I regard the Allae as a good sounding speaker, and the plinth suspension an interesting design feature. I’ve often wondered what the performance of the Allae would have been like if it had been fitted with a tweeter similar in quality to that on the SL2. The additional cost of the component could not have been much, but the performance of the Allae, already good, might have been quite considerably elevated. I appreciate, that Naim were marketing Allae and SL2 to different points in the market and no doubt tailored them accordingly.