Distortion on high (piano) notes

I’ve recently got an Atom, which I’m using with B&W 707s2 speakers and a REL TZERO subwoofer.

I had some problems with bass boom that have been sorted by using the bass port plugs supplied with my speakers, but this has necessitated an increase in volume on the Atom overall. I’ve started to notice a fairy ubiquitous distortion on higher notes, particularly from piano (eg Keith Jarrett Munich 2016).

My Atom is usually at a maximum of 45 volume. What’s likely to be going on?


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Hi Purbs

I have a few years experience with the B&W CM5 S2’s and the CM1’s, the models before your 707’s. I do recognize your problem. Since I have moved on to SBL’s, the issue is gone in my place. Unfortunately, I never solved this issue, and the bass boom fix was not sufficient for me as well since the CM’s still needed to be too far from the wall all the way in the walking path.

Retrospectively, I would try this:

  • Ensure that powerleads are as far as possible away from anything carrying a signal.
  • Try to tilt the loudspeakers a bit, just to check that the distortion is not caused by certain reflections in your room (hard walls / glass / mirrors etc)

By the way, I had the same problem with high sopranos.

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The recording seems fine through my Shure 1540s.

Not sure how amenable Sevenoaks would be to an exchange after a couple of months…

If you can arrange it so the power and speaker cables, or any other cable for that matter, don’t touch whatever the Atom is sitting on and hang free down to the floor it might help, then again it might not but it’s free to try. It did for a CDX2 on Fraim Lite when the piano was ringing too much in the high notes, I hesitate to speculate why? I’ve not played with an Atom though.

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I’d say try the suggestions which are mentioned in this topic. A friend of mine has the same problem with ProAc’s, he is entirely confident it is the recording and not his setup, however I’m convinced that a unplugging the setup and rearranging the cables would fix it.

It is most likely such a thing, takes a bit time.

By the way, do you have the 707’s on stands?

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The speakers are on bookshelves and close to the wall through necessity (6-7 cm) with both parts of the foam bung in the bass ports as per B&W’s advice.

I’ll try the above suggestions.

I have the same problem with high sopranos full scale choruses and full brass sections.Problem entered my system when i changed my cd5xs to the cdx2. Takes a perfect recording to overcome this problem, in other areas the player is brilliant.all the above solutions did’nt work.Maybe changing the cd evetually is the solution.

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I have no direct experience of your 707s but according to their specs they are not the most sensitive speakers around. The power of the Atom is towards the lower end of the recommended range. By using the port bungs you are making them still harder to drive and I wonder if that is pushing the Atom too hard. Is it really, really impossible to mount them on stands further away from the wall and dispense with the bungs?

If not, it might be worth considering a set of pre-loved Neat Iotas which work well in just the situation you’re in. I know they’re a similar sensitivity to the B&Ws but several posters on the forum have found success with this combination.

Finally, how are you getting Qobuz into the Atom? I didn’t think Naim had released the Qobuz update yet.


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I’m using TIDAL Hifi at the moment.

45 is not that high, maybe just not a good match with those speakers

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I’ve plugged my 11-year-old Dali Lektor 2s in and there’s no such problem.

Is it likely to be a bad match rather than faulty speaker(s)?

I should add that the Atom is only a few days old as it’s a replacement for one that had a faulty screen. However, I didn’t notice this problem with its predecessors (demo then faulty screen), but then I think I was more focused on the enjoyment of using the system as a whole and reducing the more obvious bass boom.

I’ll keep it on at low volume overnight and see if that makes any difference but I guess the absence of a problem with headphones or the alternative speakers suggests a matching or speaker issue?

Well my cables have never been neater and the power and speaker cables are as separated as possible considering their proximity on the back of the Atom. I haven’t noticed any improvement, unfortunately.

It’s odd that I didn’t notice this with the other 2 Atoms that have been connected to these speakers, but then again I was concentrating on un-muddying the bass and I can’t unhear it now I’m aware of it.

Hopefully Sevenoaks / B&W will be sympathetic about alternative speakers :crossed_fingers:t2:

Unfortunate that you have no luck yet!

Have you tried to tilt backwards them by just a few %? Just a coin or a pair of coins would do.

I have never tried this myself, but I’m learning about reflections these days.

When the kids are asleep, I’ll post my experiences about when I got my first hifi product: the cm1’s - mostly to give some thoughts in case you start to look for different loudspeakers.

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Thanks. The acute realisation is v frustrating. I really enjoyed an album on Friday night and couldn’t ignore the high distortion on it when I tried again on Saturday, having become aware of the issue.

Those particular notes replayed on the Atom, or any system with your speakers is putting those watts into trouble.
As have been discussed many times about what watts are. Some certain frequencies will draw more power. Some frequencies need a ton more watts to sound consistent against others.

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Thanks. Tried again sans port bungs and it’s similarly noticeable.

Try bringing out the speakers without bungs, and sitting much closer. With a reasonable volume.
Try to differentiate if it’s the front end(Amp) or the back end(Speakers).

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84dB/W dipping to 4Ω does seem rather a task for an Atom. I haven’t seen the impedance plot but another of the 7 series has that dip in the high frequencies. Is the distortion still there at low volume?
Naim used to demonstrate the Unitis with Sopra I and it did rather show the benefit of the nova but I don’t remember the high frequencies drawing attention to themselves but their impedance at high frequency is lower.

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Thanks all.

I think it’s now clear that the speakers are not a good match for the Atom.

The dealer has come good and I should be able to exchange the 707s2 speakers for something else.

Obvious early contenders include Focal Aria 906 and KEF LS50. The Focal speakers have a sensitivity of 89.5 dB, but I’m not sure how they will perform close to the rear wall, in spite of their front-facing ports.

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