Celestion SL6Si bookshelf speaker is this good for Naims?


I want to try a Celestion SL6Si, it seems this speaker has a similar character to the Spendor BC1.
Is this speaker compatible with Naim NAC 62/NAP 140 or with Nait 5 (early version) ?

maybe someone already put it together?
please review it

thank you

The Celestions are extremely inefficient speakers (sensitivity of 82-83db I believe) and need a big powerful amp to drive them. The NAP140 and Nait 5 are not suitable IMHO.

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I once had the original SL6 and I really don’t think it would be suitable as a bookshelf speaker - I would class it rather as a standmount. As said above they are also very inefficient.

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As Wugged Way says above, the Celestion SL6 needed plenty of power. Even then they could sound a bit dull and lacking a certain amount of drive and verve (For my sins I have had three pairs through my hands - two originals, and a later pair). FWIW my first pair came with a lovely NAC62 and NAP90. They were totally unsuitable with this pairing - it sounded really flat and uninspiring - which may have been why the whole set was being sold. Paired with some Royds, the 42.5/110 was so much better.

p.s. Having also inherited a pair of BC1s many years ago, I’m not sure I’d say that they sound that much alike.


I had the brother, the Celestion SL600 Aerolam which had similar dimensions of the SL6. With a sensitivity of 82db, I had to use tube monoblocks to make it sing. But when you feed them well, they just simply disappear and can do all those audiophile goodies.


And they are, like the Celestions, terribly inefficient speakers, I understand.

If the OP is looking for speakers for his Naim gear (I cannot ascertain whether he has got any - it’s not in his profile) , it would be much better if he considered the ‘usual suspects’…
ATC / Neat / PMC /Proac / Kudos etc.

Interesting, I thought it was only Pink Triangle who used Aerolam. I still have one of their shelves on a Sound Org table.

No. As @Wugged_Woy wrote, the SL6Si needs a more powerful amp to drive them given their inefficiency. One amp that works very well with them is the Adcom GFA555 - 200 watts per channel. You’d need something similar to hear how good the SL6Si can be. Great speaker, but very finicky re power amp.

Agreed. The SL600 was an upgrade to the SL6, and the Aerolam cabinet was just magic. I’ve often wondered why no speaker manufacturer has followed up and used that material. Back in the day I ran them with the massive Audio Research D-250, 250 watts per channel tubes, and later on, briefly, a pair of Naim 135.

I have youtube video sample
NAC 72/NAP 140 connected with SL6Si and I hear it seems well

Celestion SL6Si, Naim Nac 72 / Hicap / Nap 140 - YouTube

Well, if all you want to play is Art Pepper meets the Rhythm Section then you may be reasonably happy as it’s fairly untaxing stuff and sounds pretty good through most things.

Same here, also paired them with the monster ARC D250 with good results. Feed ‘em like there’s no tomorrow. Hahaha

I think I will reject the Celestion SL6Si offer because the maximum Naim I use is NAP-150x for its power and this is 50 wpc at 8 ohms

I am also interested in this topic. I have been banging on about purchasing a pair of Kanta speakers for a couple of nights and found this post from a Google search as I have been advised to keep the Celestion Speakers from a post on a Facebook Group and replace the amplifier.

If I wish the best from my Celestion speakers which are the SL6Si, which Naim amplifier what would you match them up with, please? My current amplifier is a Nait XS 2 and I believe that this is a bare minimum or maybe not even that. I read how that separates have 400VA toroidal transformers to handle current demands of complex loads or load peaks. I assume this would be due to low bass or kickdrum thumps at low frequencies presenting a low impedance load to the amplifier.

The specifications for the Celestions are 84 dB SPL, 120 watts 8ohms, and a minimum impedance of 4 ohms.

I wish to stay with Naim equipment as I have already in my mind invested so much in this brand.
Nait XS 2, CD5 XS, Flatcap XS and a non Naim product a Linn LP 12 Akurate. With a possible ND5 XS 2 or NDX 2 streamer down the track. Though these latter components are not on my radar horizon as yet. Though there are possible plans to incorporate one or the other.

I have not been happy with Celestions over time and it may be just that they do not have enough current to drive the low notes. Love the looks and also love the looks and specifications of the Kanta speakers, Numbers 1 and 2.

I do not have money burning a hole in my pocket, though I would like it to operate my current speakers as designed. Maybe they require a NAC 202/200DR or something even bigger.

Either way, an upgrade in electronics will be a good investment in my HIFI system to either supply the Celestions more oomph or the Focal Kanta’s a better preamplifier.

Oh, my mind is going around in circles as the Celestions are now 40 years old and my head tells me I need a change especially when my heart falls in love with the beauty and specifications of the Focal Kanta speaker range. Though if I can breathe new life into the Celestions and save the money that was to be spent on new speakers on new HIFI electronics upgrades, I am still winning and saving money so to speak. It is still money spent, though only on the components that require upgrading and not necessarily so the speakers.

Warm regards,


There is more to it than just the cabinet….I heard the SL700s with a Krell KSA50 and it was epic … for a small speaker. But that was in the early 90s things have moved on considerably since then…but they are still good…maybe a Statement would drive them well!!!


I think SL700 is better

That’s good … I have never heard it…I understand the 700s had an updated crossover and had a slightly better lit treble…

Update: This or a similar post may have appeared somewhere else.

I sent the SL6Si off for you new crossovers after 30 years of use. Right or wrong I do not know. I asked the audiophile repair shop to have a listen and do what they thought best. I pretty much gave them card Blanche on what to do.

Well for better or worse, the tweeters have been replaced with better tweeters that look the same as the old ones I am told. The bass drivers have been rewired and re-coned with kevlar cones. The new cross-overs are being designed.

Whether I have committed a travesty I am yet to find out. I am told the speakers are done though I will have to wait two weeks as they are bedded in.

The home is without music and I am anxiously awaiting their arrival in two weeks. The repairman said the sound as if a pillow was in front of them.

Hopefully, in a few weeks, I will have a happy post. Though as Richieroo has pointed out. Things have moved on and I am hoping these changes will be improvements.



Should be interesting, look forward to your feedback.

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