Mixed impressions from torque setting

You can have too much torque. I had to loosen my old Isobariks when they were over-tightened, as the driver surrounds then could not behave as designed and they spat-out higher harmonics that spoilt image and fine detail. Get it right and it will be good, but sometimes people think a little more is always better and in my experience it definitely is not. I have heard SL2 over-torqued and they sounded rather vile, so your ears will tell you if you are actually enjoying the music after - forget about tight bass, you always get more of that even when over-torqued - but is the music better or not? If not it is wrongly torqued - simple as that.

DB.

Hi DB,

thanks for your reply. I'll check, but - we set the woofers at the requested torque, 3.6; if I have to go back 'by ear', this will a) contradict a precise, then reasuring, datum and b) open up subjective options, which is not my cup of tea.

I'll try with another tool (although I believe that Roberto's was accurately set), but I was hoping that a prescribed value would remove issues, malfunctions and (more than everything!) options from the equation...

Best

M

If I had to use a tool such as a torque wrench at work, I'd be required to provide a certificate showing that it had been recalibrated recently to ensure its accuracy. I guess you could at least try another one on the same bolt to see if they're consistent. Alternatively, I suppose good old trial and error with reduced torque settings, tested by ear, would be as good a method as any.

Hi Chris,

thanks for your suggestion. I am not enthusiastic about setting by ear after having applied a given value, but I may try, if anything to verify that torque affects sound.

A strange experience, marrying very poorly with my repulsion for options..

Max 

My personal opinion is that you have before some sealing not perfectly working, is it possible?

I would trust your ears at least to a certain extent. Seems like quite a lot of tightening you describe, I would dial back those turns about half way to where they were before and see what you hear. It certainly won't damage anything to do that..

Remember in this hobby of ours a lot of the musical enjoyment comes down to personal preference and so measurements should be taken as a baseline value at best.

Maurizio, DC71,

thanks for your suggestions. I will try to set the bolts back to a lesser torque, and if the result is a) audible and b) of my satisfaction (provided it won't be the product of self delusion), I will avoid taking any further technical suggestion into consideration.. Because I fear that it's two opposite and irreconcilable approaches to anything. If I had known that torque setting is effective, but that it can be set by ear, why bother with a torque wrench?

Best

M

One way to test this is to rock the torque wrench all the way to its lowest setting (which is desired when not in use), then start at 3.2 N-m and move one N-m increment across both speakers. If the torque wrench is wrong, you'll know at which setting everything drops into place.

For what it's worth, I bought a Wera set (three wrenches, 0.5 N-m all the way to 6.0 N-m, if I recall correctly) for less than $200 US from Amazon, so I'd expect that they'd be cheaper in Europe.

Massimo, I have the same experience of the 3,6 Nm torque of SBL-drivers. It feels like it is too much and it did sound worse than the much looser setting that was before

David,

thanks for the suggestion, I'll take a look at Amazon or some online store. If I add the cost of it to the hypothesis of spending €160 for the gasket/pads/silicone kit, I realise that SBLs are somehow high-maintenance..

Stormange,

how did you solve it? Just de-torquing some by ear?

Thanks

Massimo 

Ok, I took the proper allen key and, very carefully, loosened each bolt half a turn, starting from upper righthand and crossing. The allen key was inserted in the same position in each bolt, thus suggesting that they were consistently matching. Loosening them just one half turn, they seemed to became tactilely loose, not to the point of removing them by hand but certainly nothing suggesting over-torque; and I could not, sincerely, hear any clear difference.

My impression, after this, is that Roberto had done a good job, the bolts were actually the requested 3.6 and if there are issues, these are not coming from the bolts. Now I'll proceed to check my ears' and my mind's torque.

Thanks

M 

About £50 0nline. Proxxon  MicroClick  5  1-5Nm torque (0.1increments)

Hi, thanks. I'll look.

Best

M

This is the wrench we used,  i bought it  last year and was only used a  couple of times setting up SL2s woofers and aluminium plates , so i assume being it reasonably accurate. In fact i tried yesterday   into my woofer bolts,  and at first touch the  mechanism started to click.

For the record, over the last 2 weeks my system has lost either 282 and Hc DR replaced by

bare Nait XS and i confess that is still amazingly good still

Btw my dealer just  confirmed me the forthcoming  arrival of a nice pre loved 252/S.Cap

Regards

Roberto

sheffieldgraham posted:

About £50 0nline. Proxxon  MicroClick  5  1-5Nm torque (0.1increments)

I also use a Proxxon tongue-driver [as picture above] and been using it couple of times a year for past  3 years.

Just checked my SBL mid/bass driver bolts by; undoing them with the tool set at 2.5Nm, which may go to prove the bolts do loosen off with time.

Just my observation but the 3.6Nm doing up setting is very firm, and would appear as firm as one could safely tighten the bolts up with-out risking thread-strip. This suggests the intended setting is an accurate figure of the highest torque measurement to get those bolts done up as tight as possible without causing damage.

IME my SBLs do sound better with the driver bolts correctly torqued up at 3.6Nm.

Debs

Just to confirm - the SBL bass drivers on your pair are, in fact, the Naim-built, die-cast ones (six-sided), correct, as opposed to the early (pressed?) Naim-modified / Mordaunt-Short manufactured (four-sided) ones?

I could be wrong, but I distinctly remember there being some difference in preference for the torque settings for the older drivers - or I'm imagining that.

naim_nymph posted:

Just my observation but the 3.6Nm doing up setting is very firm, and would appear as firm as one could safely tighten the bolts up with-out risking thread-strip. This suggests the intended setting is an accurate figure of the highest torque measurement to get those bolts done up as tight as possible without causing damage.

Debs

Same findings here Deb.

Not sure if anyone will agree, but I tend to slacken off the bolts and leave overnight to allow the woodwork to relax  (Allaes). I then torque to 3.6Nm.

DavidDever posted:

Just to confirm - the SBL bass drivers on your pair are, in fact, the Naim-built, die-cast ones (six-sided), correct, as opposed to the early (pressed?) Naim-modified / Mordaunt-Short manufactured (four-sided) ones?

I could be wrong, but I distinctly remember there being some difference in preference for the torque settings for the older drivers - or I'm imagining that.

Yes my mk1 SBLs were upgraded in 2010 with the mk2 type mid/bass drivers.

I didn't own a torque driver in the years when i had the early SBL version so never experienced torquing them, and i don't know if they have a different torque preference, not heard about it but suppose it's possible.

My little stand mounted 1989 Mordaunt-Short 100 gold speakers have a similar 4mm allen key bolt arrangement on their mid/bass drivers, and they feel plenty tight enough at 3.0Nm.

But i wouldn't like to say if this is relevant to the early SBL drivers, need a directive from naim engineers.

Debs

Thanks to those who have replied, confirming that someone else had experienced at least ambivalent feelings about the torque/sound relationship.

Honestly, I could not say that the difference I heard was a) real, b) negative: it happens frequently that my ears, mind, mood, mains et cetera have some influence on the sound, so I will assume that 3.6 is correct, will stick with it for the future and leave the thing alone.

Thanks for the couple of tools suggested, I'll take a look online. Roberto's one is very fine, but a little too expensive for me..

M.

Hi Max, I've email problems at the mo, and will drop you a line as soon as they are fixed. (This seemed the best way of letting you know!)

Hope you can get this torque thing fixed.

Best, C.

Ok, thanks. The torque thing, at the end of they day (literally, it's 00.01) will be fixed with the purchase of a torque wrench and occasional check of the bolts. (And yes, new gaskets are also in agenda..).

M.