Castle Knight 4 Loudspeaker REVIEW

April 23, 2012
5 mins read

5 Stars

Can the rebirth of Castle relive past glories? Looks likely!

A LONG TIME ago (in a land not far away from here – High St, Auckland, to be exact) I worked weekends at a friend’s hi-fi shop. Well, we sold a lot of audio equipment and had a ton of laughs along the way, and I was lucky enough to be exposed to some really great quality gear.
That shop was The Audiovision Centre, and my friend was (and still is) Andrew Simpson.
Not only did he sell great equipment from his tiny shop, but he also imported household name brands such as Musical Fidelity, Nordost, Definitive Technology and PS Audio. He also imported speakers from a Yorkshire-based company called Castle Acoustics, and I was lucky enough to meet the then MD Graham McGee on a number of occasions.

I quickly became very fond of the Castle ethos – exquisite hand-made cabinetry combined with high-tech drive units made in-house at their factory in Skipton. The use of quarter-wave ‘Voigt’ bass loading, tuned to provide musicality and warmth, possibly came at the expense of speed and accuracy, but this enabled long listening sessions without constantly changing CDs or records.
Considering their mid-market pricing at the time they seemed to do everything right, so I bought a pair of Harlech floor-standers, and these were quickly followed by a pair of Richmond 3i’s (as rear HT speakers), the Classic subwoofer and a Bastion centre.

Harlech S2.

They were fabulous speakers as a package, and still are because in spite of numerous speaker purchases over the last few years I can’t seem to part with them.
Which bring me to the present day: Castle essentially crashed and burned due to financial issues in 2006, and lay dormant for a few years before rising from the ashes under the IAG umbrella. Castle is an iconic British brand that I have quite an investment in (both in terms of financial and emotional outlay), but judging by the efforts put into their new stablemates (Mission/Quad/Wharfedale) I was confident they wouldn’t stuff things up and ruin one of my favourites.
So lo and behold, a pair of spankingly new Castle Knight 4’s ended up in my listening room for a good old four-month review (well, in between seafaring duties, that is). They are a new range for the company, sitting below the Classic range spearheaded by the luscious Howard flagship.

The 4’s are second from the top dog Knight 5 (obviously); the Knight 3’s are the entry level floor-standing model, the 1’s and 2’s both being stand-mounts. Once unpacked I had to attach the plinths to each cabinet, and once I’d screwed the spikes in the speakers were ready to make some music. Nothing seems to have changed for Castle under the new ownership if the Knights are representative – they are sturdily built and beautifully finished. The sample speakers came in a perfect real-mahogany wood veneer, while the plinth, spikes and binding posts were of a very high standard.

The Knight 4’s use 2 x 130mm polypropylene bass-mid drivers and a single 25mm textile dome tweeter in what’s called a ‘twin-pipe’ enclosure (see pic below). Essentially, an internal division is angled towards the front of the cabinet, and these two cabinet ‘halves’ are tuned to different frequencies. The internal air flow travels through a port at the bottom of the cabinet and then hits the solid plinth, creating back pressure and therefore ‘loading’ the cabinet. It’s very similar to the quarter wave design of my Voigt ‘Vofo’s’, and differs from my trusty Castle Harlech’s as the internal division in those speakers completely separates the cabinet halves.

Knight 4 internal build

With a fairly high sensitivity of 90db they are also tube friendly and shouldn’t need too much power to drive them – although more power is better than not enough.
So with tech stuff out of the way – I cabled the Knights up to my Audiolab 8200CDQ/8200MB’s and the rest of my cast of thousands (Squeezebox Touch/Pro-Ject RPM12 ‘Studie’ and even my almost forgotten Cambridge Audio Azur 650BD Blu-Ray player for DVD-A/SACD duties)

I gave them a bit of time to run in properly, and over this time I really got to grips with what is a surprisingly good sounding loudspeaker.
They have a laid-back tonal signature common to the Castles of old, maybe a touch loose in the bass (in a warm fashion) and are not overly detailed or ‘fast’ (as opposed to the Linn/Naim sonic signature).
What they are though is very easy to listen to for extended periods. There’s no etchiness or stridency at the top end, and the midrange is clear and openly defined.

Knight 4's in all their glory

The first track I listened to was Gotye’s ‘Somebody That I Used To Know’ from his rather good Making Mirrors album. This is a stripped down recording with an enormous amount of emotion and feeling in the song, and the Knight 4’s made a damn good fist of portraying it all.
Both Gotye’s and Kimbra’s vocals appeared in mid-air between each speaker, while the quirky synth sounds (although not all, Gotye makes some of his own instruments) danced between and outside of the speaker boundaries.
An excellent start then, and after familiarising myself with this latest Aussie sensation it was time for a bit of Kate Bush, as I was in a most melancholic mood (it wouldn’t last though).
50 Words For Snow is her latest album, a pared-back affair with mainly piano and Gregorian-type backing vocals. It’s a work of delicacy and requires a deft touch from the electronics and loudspeakers let alone sources. Once again the little Knight 4’s communicated the album extremely well, and Kate’s plaintive vocals were captured with her trademark breathiness and inflection. The piano sound had great timbre and surprising heft at the bottom end, definitely a revelation for a small-ish speaker with 130mm drivers.

Once I’d listened to her album (and I mean ‘listened’) it was time to up the tempo somewhat and bring myself back to life with some rockier stuff. Well, blow me down if I didn’t choose Dire Straits, my most-loathed band of the ‘80s. I actually went to three concerts back in the day and walked out on two of ‘em, but for some reason I seem to have had a change of heart in recent times and have gone out and purchased all their early stuff. That being said, horrific tracks such as ‘Money For Nothing’ and ‘The Walk Of Life’ still produce nausea.
So onto the Squeezebox went ‘Tunnel Of Love’ from Making Movies. It’s a rather dour affair, but somehow it evokes memories of my youth around Auckland city. It’s a decent recording with a rather fat bass and splashy treble, and that’s pretty much what I heard through the Knight 4’s – albeit with one difference compared to a lot of speakers I’ve heard this track through. I could listen through the whole track (and album) without walking away or changing tracks.
So in summing up, it’s a more than favourable review of Castle’s beaut little Knight 4’s. I did have my concerns about the change of owner – would they change what was (to me at least) a winning formula?

Luckily my fears are unfounded. If these are representative of the new Castle sound then they need to be considered if you’re looking for a quality pair of transducers at this price-point.

In fact, the Knight 4’s certainly didn’t sound like an $1800 pair of speakers, they punched well above their weight and didn’t sound out of place on my system. Impressed – hell yeah. Go and audition a pair. GARY PEARCE


  1. Gary, why is it that people tend to associate loose base and warm sound with a “listenable” speaker. I actually value tight bass and detail but with a good speaker don’t find that detracts from “listenability”.

  2. Hey Tony, yes I get your point: the Knight 4’s however I need to qualify my comments regarding their ‘loose bass’ – in the system I reviewed them on (ie mine) there was a melodious tone to the bass, it’s not quite as crisp and detailed as some speakers I’ve heard but pleasing nonetheless. We’re not talking about boom and bluster here, it’s just not quite as crisp and pinpoint as speakers from some other manufacturers (did I mention Linn or Naim?). Certainly the overall tonal signature of the Castles is a warm one compared to the aforementioned and very pleasing to my ears, the bass performance only added to the enjoyment.
    Now there’s nothing wrong with a ‘fast’ sounding speaker at all, but in my experience those with a warmer tonal quality have me pinned to the couch for longer periods of blissful listening. The ‘rich’ sound quality is common to Castle in my experience, so I guess it’s a sq I’ve become accustomed to and to be honest, I’m rather fond of it 🙂


  3. Hi Gary,

    Nice review. This is a shot in the dark but I need some help re castle howard s2s. I bought a pair ex demo from holburn hifi in Aberdeen, in 1996 and they are still magnificent.

    They are coupled with audiolab 8200cd, naim nac32.5, 2 nap 110 and a HICAP.

    The problem is one of the drivers (top woofer) was damaged in transit to South Africa from the UK. It flutters, so I had to disconnect it from the x/o (obviously, did the other speakers top woofer too). Amazing how good they still sound.

    Anyway, the problem is I’ve been trying to source a replacement driver for a few years now to get back to full performance. I tried Castle directly and web generally, but still have had no luck.

    I have heard of a guy called Andy in forums who designed the drivers, but haven’t been able to make contact yet…

    Do you have any suggestions for where I could source a replacement driver? Do the new manufacturers’ drivers match the old kit?

    Many thanks in advance for any help.

    Kind Regards

    [email protected]

  4. Hi Don,
    Bad news I’m afraid. The Howard S2’s are long gone as a model, they were replaced just before the millennium if my memory serves me correctly. I would look for a certified loudspeaker repairer and get the errant driver assessed and hopefully fixed, if the cone material isn’t utterly torn up pretty much all drivers can be repaired successfully (even replacing voice coils).
    The current S3’s use carbon fibre cones and not paper pulp like the S2’s, and now that IAG own Castle there’s practically zero chance of obtaining the earlier drivers. However, the S2’s are a beautiful speaker and worth restoring Don!



  5. Hi all,a useful contact for speaker refurbishment is wembley loudspeakers,i have had 2 pairs of castle drive units reconed and voice coils replaced ,one was a pair for my castle harlechs both gave excellent results just do not expect them to break any records turning them around they are very busy!Contact number is 02087434567 google will find their web site,hope this helps.
    Regards neil

  6. Thanks Neil – did you have the original Harlechs with white polypropylene cones? Down here in NZ with the high UV light they cracked terribly. The change to Carbon fibre fixed the issue, but I thought the 1st gen Harlechs had the edge in sound quality. Rumours are that Castle will launch a totally new Harlech sometime this year using a ribbon HF driver, this will be one of their flagship models.
    Can’t wait!

  7. Hello Mr. Gary,
    Thank you for the nice review! I just came across this and it is exactly what I was looking for. Not a lot of reviews out there of Castle. I have had a fondness for Castle speakers for a long time. I used to own a pair of the Warwick 3’s. I am now looking to buy a new pair of Castles. Unfortunately, there is no distributor here in the States for them any longer. So I will have to buy them unseen and unheard from Canada.
    Maybe you can help me out and be my ears? I was wondering if you had the chance to hear anything recently from Castle’s Classic line?
    I really like description you gave of the sound coming from the Knight 4’s. That is the sound I am looking for. I am leaning towards buying the Knight 4’s but I am also wondering about the Classic lines Stirling or Conway speakers. Perhaps they might be a better choice and sound a lot better, or not? Wondering how they compare to the Knight 4’s?
    The Stirling and the Conway both use a Carbon fiber mid woofer driver and a 28mm soft dome tweeter. The Knights don’t use the carbon fiber mid woofer and the website says it uses a 25mm textile dome tweeter. Not really sure what the difference are between a textile and a soft dome?
    The Warwick 3’s that I used to own (sold to my brother in-law) have the carbon fiber woofer but uses a smaller 19mm polyamide dome tweeter (again, not exactly sure what polyamide is). Although I loved those speakers, I wasn’t 100% sure about the tweeter quality. The overall sound of the speaker was very good but I thought the upper frequencies could sound a bit pinched and bright in some circumstances.
    Anyways, any help you can give me will be much appreciated.
    Thanks in advance!

  8. Hi Gary
    Thanks for the review. Its very helpful. I am planning to match these speakers with yamaha a-s500. What would you say about this combination?

  9. Devrim the Knight 4’s are an easy to drive loudspeaker, I think the AS-500 would be a superb match for them – find a Yamaha/Castle dealer and audition them!

  10. I was waiting a long time for you to answer my comment. You answered everyones comments except mine. I don’t know why?

  11. Thanks Andy B. Yes it helps.

    I don’t know what happened to Gary’s response, perhaps he hates Americans? Ha.

  12. Sorry for my lack of reply Tom, I actually love Americans (especially hot ones with boobs).
    I’ve had a change of career lately that allows precious little time for anything audio, even listening to my HiFi has become hit and miss!
    Now I haven’t heard the reincarnation of Castle’s classic line under IAG (although Mr Baker has heard the Howard S3’s as evidenced by his excellent review), but his observations mirror mine in terms of their overall sonic signature (I used to sell Castle when they were produced in Skipton).
    Of all the classic line speakers the Stirlings were the most lively and detailed, with a tight reasonably extended bass register and clear midband.
    The Harlech S2 (still got ’em!) Howard S3 and the Conway (and the Avon, a previous model) didn’t quite deliver as much detail but were warmer in tone and I found them easier to listen to for extended periods.
    A halfway house would be to use brighter electronics with them, I used fairly budget Rotel mono amps with my Harlechs with great results. This combination worked exceptionality well and would work well with Conway/Howard S3 and the Knight range – however I’m picking the Stirling’s could become a touch bright using this type of amplification. Still a great speaker though, bit I’d look at a warmer, less strident amp/source combination.

  13. Thanks a lot Gary for getting back to me. I really do appreciate it.

    The distributor in Canada said that they didn’t carry the Classic line because they all thought the Knight series were much better sounding. Not sure how true that is? Seems a bit odd to me.

    Wondering how the Knight series compares to the new IAG Classic Series? Wondering how the IAG Classic Series compares to the older Skipton made Classic ones?

    I have to buy before I can hear them. I might go for either the Knight 4’s or the Conway’s. The Stirling’s are a better size but I like a warmer sounding speaker. There is a Skipton made Severn 2 SE for sale. Never used the ad says but not sure how old they are. Maybe I should jump on that pair and buy them.

    You sound like a busy man Gary so I won’t take it the wrong way if I don’t hear back from you for another year. I’m glad that hot, well endowed American women hold your attention. I may not be a woman but I am American and I am middle aged so I think I got some small boobs going on by now 🙂 ha


  14. Hi Gary
    Nostalgia strikes! Looking for web reference to Castle Harlech, I read your intro re the High Street shop and Andrew. On Sep 29 1997 I bought my outfit from him, still sounds terrific. Two Harlech speakers, amp, tuner and CD player all Musical Fidelity, and I have a Linn Sondek LP12 recently brought up to 100% sound. Now on the deaf side of life I’m thinking of selling it as a going unit, and I have approx 400 vinyls to go with, all areas of music, 100 78rpms, 50 x 45rpm, some 10″, 25 boxed sets the rest single LPs. Also some 60 CDs (single) and 8 boxed sets. Any clues as to a value? I’d much appreciate your comments.


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