Naim Uniti Atom - putting some weight on sound

Hi All,

Looking for some advice. After many years of owning a seperates system (Marantz CD63SE MK2 KI/NAD3020/KEF speakers) I have “upgraded” to a a Uniti Atom/KEF LS50 metas/stereo REL T5X, on Chord shawline X cables. The sound is very good at low volume but seems a little lightweight ( lacking punch/grunt; apologies I don’t know the audiophile term…) at volume (45+).

Would using an amp/power conditioner or other trickery help improve or should i stick with it until i can afford to go back to the separates route?

I was thinking of a potential upgrade path of either XS3 - XS2 or NAP250-ND555 (will take longer to afford) followed by speaker upgrade after the streamer has been added

Are the speakers on good quality stands? Try varying speaker distance from front wall and alternative cables such as NACA5 or TQB II.


Which speakers did you used to have?

The CD-63 MkII KI was a very well regarded player in the 1990s (when I bought my Micromega Stage I recall the KI was a WhatHiFi best buy for £400ish - maybe 1996?)

However a 3020 could never be described as powerful.

Having checked an old photo the amp was actually nad 317, speakers were kef iq5 floor standers.

If you’re used to floorstanders it could simply be that the metas don’t shift as much air, especially at high volume.

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They are on custom 36mm mdf cabinets, i have played with distances, bass isnt the issue as the subwoofers deal with that, its the midrange and tweeters seem lacking, rels have been dialled down to match speakers but it just feels like the system coild do with another 40-50 watts. Will look at cables, thanks

Whilst I can’t help with an answer to your question, Chuuno, I was intrigued by your choice of kit. Just over a year ago I retired my Arcam Alpha 8SE CD player and Linn Intek amp and “upgraded” to the Naim Uniti Atom with Shawline X cable. I auditioned the KEF LS50 Meta, KEF R3 and B&W 706 S2. I decided to go with the B&Ws together with matching FS 700 S2 stands (now sand filled). I’m really pleased with them at any volume.
I’ve now completed my kit with a pair of Meze 109 PRO headphones.

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When auditioning speakers i looked at ls50 metas, r3 and r7s along with some focal 948 the r7s and focal seemed to expose the low amp power and the ls50s seemed clearer at low volumes vs the r3 ( which is required when family are around) but lacked a little in the low range so the subs which do improve the soundstaging

What size is your room?

The KEFs are relatively small stand mount speakers. Looking as the specifications there are a couple of things that stand out as perhaps attributing to what you describe:

  1. low sensitivity: 85db is a pretty insensitive speaker. Yes the Uniti Atom has ‘Naim’ watts but perhaps, when being asked to drive a low sensitivity speaker (with an impedance dip down to 3.5 ohms) at higher volume then it begins to loose some authority/control.

  2. A bass-light tonal balance: -3db at 79 hz and - 6db at 47hz means that subwoofers (which you have) are definitely needed for full range music. The typical in-room figure assumes room gain which will depend very much on your room.

Assuming that your speakers are wired correctly in-phase (incorrect phase will give a bass-light presentation, especially at higher volume) may I suggest you:

  1. without the subwoofers on, experiment with speaker positioning: even a small amount of adjustment can really make a difference to response at the listening position. Distance to the back wall and toe in/out are all crucial. If the speakers are on furniture, bring them to the front to avoid reflections from the top of the surface below.

  2. set the subwoofer’s crossover and phase. Given the KEF’s high F3 point (the -3db figure) of 79 hz I would start with setting each REL at that point. This might give too much bass at first but you could then dial-down the gain on each subwoofer. Alternatively you could gradually lower the crossover point according to your taste/how the speakers behave in your room.

Relating to this, once you have chosen your crossover point, using something like REW, play a test tone at the crossover frequency on each subwoofer in turn and adjust the phase switch. The setting that gives the fullest output is what you should leave each phase setting at. If output drops you are effectively getting frequency cancellation at the crossover point, which would manifest itself as less output around the upper bass/low mid-bass point, I.e. just the frequencies that give ‘punch’/depth to the music.

I suspect that, assuming everything is wired correctly and the Atom is up to driving the Metas in your room, some correct setting-up of the subwoofers to work with the Metas is what is needed. If nothing else it is something that you can do without spending any money!

Hope this helps.


My experience with the original LS50’s was they needed around 100wpc to wake them up…

I use my Atom with little Neat Iotas which are even less sensitive than your Kefs, although that’s into 6 ohm impedance, so not directly comparable. In the small bedroom I use as an office, it fills the room with extremely enjoyable music. But it doesn’t have anything like the weight of the main system in the lounge and I’d be pretty annoyed if it did, given the relative costs of the two setups. Good though it is, the Atom is, after all, at the bottom of Naim’s current range.

I’d be inclined to follow the suggestions above and do what you reasonably can to improve things for now, but realistically you probably need to be looking to upgrade the amp and source and probably loudspeakers too in the long run.


Room size is 4.5 x 8metres with speakers 2metres apart along the 8mtr wall. Listening position is3.6 mtrs from centre line of speakers which are 300mm from external wall . Thanks very much for the helpful insights, will spend some time experimenting with both speakers and subwoofer placement, am happy with current crossover point but have dialled down sub woofer volume so they dont overpower the speakers but will redo.

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Thank you Roger, i definitely don’t expect Naim seperates level, it was rather compareson to the cheaper old marantz/nad/kef set up i had previously owned

When it comes to subwoofer integration, I’ve found two different approaches that work well for me.

  1. Set a high(er) crossover point but a relatively low gain. This will give some overlap with the main speakers around the crossover point but is useful if your room causes bass nulls around this frequency at the crossover point at your listening position. I use this to great effect (IMO) in my main system using 2 x BK Electronics Gemini II subs (down firing 10inch drivers, 19 litre cabinets, 150 class A/B amps) with my Tannoy floorstanders running full range. I also found acoustically decoupling the subs from the floor using some DIY sub risers really helped clean up the bass response.

  2. the opposite. Set a relatively low crossover point but raise the gain level. This works with relatively small subwoofers as they do not have a flat frequency response down the 20hz (this requires a lot of cabinet volume/larger drivers etc.). Running higher gain at low frequencies could effectively flatten your bass response as the subwoofer’s internal crossover/HPF will have a slope (typically 12db per octave going up the frequency range) that, when combined with careful use of a sealed cabinet’s natural bass roll off of 12db per octave going down the frequency range, will give a range of relatively flat response. A graph would help illustrate this but if you imagine it looking a bit like a flattish-topped mountain with a slope up from the left being the subs natural low frequency 12db roll off and the slope down the right being from the high pass filter’s roll off figure.

A useful thing to note is that the T5x has an F6 of 32hz, meaning they are -6db at 32 hz so some boost in that region might be helpful. Running two subwoofers as you are doing is certainly a very good way of helping with bass response and it also gives you more headroom.

As with anything, rooms all behave differently with regards bass response so experimentation is key but I thought the above could be useful to give some idea of the ‘science’ behind different approaches to subwoofer integration.

Thanks for the advice Alex, i will have a play

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Try Dynaudio Evoke 30, magical sound

Along with the speaker and sub positioning advice above, may I ask if in the past you ever turned the bass up on the NAD? I moved from NAD to an Atom and had the same initial impression. It took me a while to adjust and move away from my prior bass-heavy tendencies. Also, you’ve moved from 80W to 40W so I’m not surprised a certain amount of “grunt” has been lost - surely in place of refinement :wink:

I never played with bass and treble on the nad and was happy. It is not the bass thats the issue more midrange and tweeters, the subwoofers mean no bass issues. It is just the 40watt i guess i will have yo save up yor an upgrade :rofl::rofl::rofl:

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