Beolab 50, Home HiFi Show 2017

For the first time in a while I have been to a hi fi show, this time in Harrogate, North Yorkshire. It was arranged by the forum HiFi Wigwam, and there were both commercial and amateur exhibitors. It was fairly low key: not all that many exhibitors and not too many visitors on the day I was there (Saturday). I liked the venue, The Old Swan Hotel.


My main reason for going was to hear the Bang and Olufsen Beolab 90s, but those weren’t there. Instead the Beolab 50s were being demonstrated in a very large room as shown above. There was a technical problem: they couldn’t change the settings for the speakers because of wi fi issues – it can only be done from a phone app (I think) and it needs to find the speakers on the network. So they were stuck on a fairly omni-directional setting and I could really hear this: I desperately needed them to be more focused. But anyway, very generously, the sales guy allowed me to play tracks off a memory stick I had brought, and gave me control of the volume.

My impression was of a beautifully clean, effortless sound, and incredible bass, but the setup was just ‘not right’ and everything sounded too diffuse and distant. Nevertheless, I enjoyed playing some good demo tracks and it was easy to hear that these speakers are not troubled by high volume levels – although I didn’t get anywhere near the volume they normally run demos at!

I must try to get a demo when they are set up properly – I expect great things from them. (I feel a bit of a fraud though, because at over £20,000 I won’t be buying them!).

My friend was very impressed by the looks of these speakers: solid-looking aluminium, fine wooden grilles, and a tweeter ‘pod’ that disappears when the speakers are inactive. In fact, he was very taken by the whole B&O ‘ethos’. Even the remote control for the system was a work of art, being made from a single piece of aluminium. And B&O do the best brochures of any hi-fi company, I think!

In the rest of the show, we heard some enormous horn speakers – I am not a fan, KEF LS50 wireless, some BBC-style LS5/9, some early Harbeths, some Focal speakers, some tiny actives based on balanced mode radiators, and quite a few others. There were various vintage components from the 1970s onwards. My friend was quite taken with the sound of some very classic-looking Tannoys with concentric tweeters, and anything that sounded good on a lower budget – I don’t have the brochure to hand, but may fill in some more details later.

Valves were on show of course, a few turntables, some outrageously inefficient Class A solid state amplifiers, and some active crossovers. In some setups, vinyl sounded OK, but because of the pops and clicks I often found myself wishing for digital sources!

There were the usual vinyl stalls, cables and accessories at eye watering prices, an interesting exhibition of photos of pop stars from the 60s and a great jukebox.

Acoustics-wise, the standard rooms were quite good, I thought, having higher ceilings than some other places.


Sgt. Pepper’s Musical Revolution

Image result for howard goodall sgt pepper

Did you see Howard Goodall’s BBC programme about Sgt. Pepper? I thought it was a fine tribute, emphasising how fortunate we are for the existence of the Beatles.

Howard did his usual thing of analysing the finer points of the music and how it relates to classical and other forms, playing the piano and singing to illustrate his points. He showed that twelve of the tracks on Sgt. Pepper contain “modulations”, where the songs shift from one key to another – revealing very advanced compositional skills needless to say. But I don’t think that the Beatles ever really knew or cared that music is ‘supposed’ to be composed in one key and one time signature – they were just instinctive and brilliant. To me, it suggested that formal training might have stifled their creativity, in fact.

He supplemented his survey of the tracks with Strawberry Fields and Penny Lane which although not on the album, were the first tracks produced from the Sgt. Peppers recording sessions.

The technical stuff about studio trickery and how George Martin and his team worked around the limitations of four track tape was interesting (as always), and we listened in on some of the chat in the studio in-between takes.

Obviously, I checked out what versions of the album are available on Spotify, and found that there’s the 2009 remaster and, I think, the new 50th anniversary remixed version..! (Isn’t streaming great?)

Clearly the remixed version has moved some of the previous hard-panned left and right towards the middle, and the sound has more ‘body’ – but I am sure there is a lot more to it than that. The orchestral crescendos and final chord in A Day in the Life are particularly striking.

At the end of the day, however, I actually prefer a couple of more stripped back versions of tracks that appeared on the Beatles Anthology CDs from 1995. These, to me, sound even cleaner and fresher.

But what is this? Archimago has recently analysed some of the new remix and found that it has been processed into heavy clipping i.e. just like any typical modern recording that wants to sound ‘loud’. Archimago also shows that the 1987 CD version doesn’t have any such clipping in it; I won’t be throwing away my original Beatles CDs just yet…

The Trouble with Hobbies

Have you ever suddenly been inspired to embark on a brand new hobby?

Maybe you’ve never owned a boat before, but having seen one chug by on the river you have thought “I’d love to do that!”. A quick browse in the classified ads shows lots of boats that look fine, and they don’t cost all that much. Basically any boat would be great, and you could gradually do it up, even if it is a bit shabby now. In your mind’s eye, your family will love you when you are able to take them on spur-of-the-moment, cheap weekends messing about on the water, starting in a few weeks’ time.

From this high point where the world is your oyster, you begin to take the advice of the magazines and other experienced hobbyists. Before you have even owned a boat, you become aware of the hierarchy of boat owners, and the boats that would render you a laughing stock if you owned them. You become aware of the general consensus on different types of bilge pump – not something you ever wanted to know. You begin to form an idea of the boat you should really go for – and it is not one of the bargain basement jobs you first saw. You might just about be able to stretch to a boat that would put you in the lower echelons of boat ownership but, importantly, not on the very lowest rung. You could always, perhaps, move up from there over time.

It now turns into an all-consuming hobby with the goal of having a boat on the river at the end of the year. In the end it costs thousands, and your children have grown up and left home before your boat finally takes to the water. You hit a bridge and rip the top off your boat the first time you take it out. You feel sick and abandon the whole hobby (a true story).

That’s the nature of male hobbies. They start out as wonderful, spontaneous ideas, but can turn into nightmares – mainly due to the existence of other hobbyists! Audio is one of those hobbies, I think. Ridiculously, the prices paid for bits of audio knickknackery rival the costs of boats.

A person could be seized one day by the idea of hi-fi as a way to improve their life, buy an amp and some secondhand speakers off Gumtree for £100, and plug their tablet or laptop headphone socket into the amp using a £2 cable. Hey presto, a hi-fi system that will sound much better than what they had before, and which has tinker-ability via the buying and selling of speakers and the audio streaming/library software options; there is no urgency in changing the amp and tablet hardware as they are pretty much perfect in what they do. The speakers are almost like pieces of furniture, so the person can indulge their tastes in how they look as well as how they sound, and they can be restored using standard DIY skills – a nice mini-hobby.

But what if the person does the natural male thing, and starts to read the magazines and forums? Immediately they will realise that their tablet’s headphone output is a joke in the audio world. They need to spend at least a few hundred pounds on a half-decent ‘DAC’, plus a couple of hundred on a budget cable. And of course, this is only for convenience: real audio quality can only be had if they own a decent turntable and a special vibration-free shelf to put it on. Where do they go from there? They need to make a decision on which turntable and which cartridge to go for. They need to take a view on cables, power conditioners, valve or solid state amps, accessories like cable lifters and record cleaning machines. Each decision, they are assured by their fellow hobbyists, will result in “night and day” differences in the sound.

After some months agonising over it, they assemble a beginner’s system for about £3,000 – they will upgrade as budget allows. It sounds OK, but they know that even though the brand is a highly recommended one, the particular model of valve amplifier they could afford has “hints of a slightly reticent mid range” – one of the magazines said so – and if they listen carefully, perhaps they can hear that… But the more powerful 18 Watt model cost £800 more and they decided against it. Perhaps they made the wrong decision. The nightmare unfolds…

Vinyl sales overtake digital


It seems that a milestone was passed last week when UK vinyl sales hit £2.5m versus digital’s £2.1m. Vinyl has enjoyed eight straight years of growth.

It’s no skin off my nose, except where new recordings begin to be produced primarily with the vinyl release in mind. This is where dynamics are reduced, bass and treble attenuated, and stereo effects restricted while the recording is being made, rather than a special post-processed master being made for vinyl. We digital listeners are then forced to listen to the less dynamic version as well.

I just had a quick look to see if I could find an actual ‘Top Tips for Mastering Vinyl’ example for the above. The first site I looked at contained this:

Mastering for Vinyl

…For minimalist recordings, you want to try and minimize large phase differences between channels… This means that spaced omnis are really not such a good idea if you can avoid them.

If you can’t avoid them, try and put loud bass sources in the center of the soundstage, as close to the center mic as possible. Even if you are using coincident miking, this is a good idea.

In other words, once vinyl becomes a major consideration, actual recording techniques are dictated by the medium. In the example above, it is not crazy studio effects that are being limited, but the microphone placement used in minimalist recordings that you might have thought were not a problem.

Hi-Fi Sci-Fi

stone tape

Last night I watched a BBC TV play from 1972 called The Stone Tape. An electronics company installs its R&D department in an old mansion, with the aim of developing “a new recording medium”. Tape is, apparently, “too delicate and it loses its memory”. They stumble upon a possible ready-made solution in a room in the oldest part of the house, which seems to have a ‘ghost’ – a Victorian maid frozen in time just before she fell to her death. What if it’s not a ghost, but a ‘recording’ of an event that has somehow become embedded in the stone itself? Maybe this could be “the big one” they have been looking for…

What I particularly liked about it, was the idea that – hard to believe – there once was a time before the world went digital, and when everything was still up for grabs. Digital computers do play a role in the story, but only as a way of “correlating” the experimental results in order to spot possible connections that a human might miss.

It’s also a well-observed portrayal of life in a certain kind of company – some of it seemed very familiar.

KEF Concord in print

I just noticed that Ken Kessler’s lavish book on the history of KEF contains several pages on the Concord – the speaker I have been re-building in active form. He makes it sound like a much better speaker than I found it to be prior to conversion, but maybe I just had a bad pair.

The mark IV version looked subtly cheaper and less sophisticated than the III due to small details like the badge, base plinth which was now plastic and the texture of the all-round fabric. It had a removable plastic cap on the top of the enclosure, and it seems that this was to allow users to change the ‘sock’ for different colours, although no one ever bought anything but black and brown, leaving warehouses full of the other colours – how I would love to have some of them now!

There’s also a story of one of the bosses getting his wife to try one on as a boob tube…

UPDATE 07/10/16

I bought some KEF Celeste IV (the Concord’s smaller sister) for the original stands, in order to use them with my Concords. It isn’t all that straightforward to re-use the stands with my version III speakers, however – some engineering is going to be required. One Celeste tweeter wasn’t working so I replaced both with the ones from my Concords which are supposedly the same type. They now actually sound quite good – much better than I remember my Concords sounding.

KEF Concord III conversion

kef badge

Recently, I thought I might try to combine modern technology with the styling of 70s hi-fi by converting a pair of KEF Concord IIIs to work with DSP active crossovers, and also upgrade them from 2.5-way to 3-way with all-new drivers. The scheme is based on the same software and DAC that I used for my earlier DIY effort.


Some KEF Concord IIIs (not my particular pair) []

I bought the KEFs a few years ago because I thought they looked fabulous. I thought they would sound OK because they’re not tiny and contain two 8 inch drivers. I was wrong: to me they sounded weak and ‘boxy’, so it required no soul-searching for me to decide to modify them irreversibly. Who knows: maybe they had bad capacitors or something, but as you might have guessed, I probably wasn’t going to be keeping them in their original form, anyway.

I didn’t give my conversion project much planning. I already had some Peerless 8″ polypropylene drivers bought very cheap, which WinISD indicated were perfect for the enclosures, and I thought I could cross these over to 3″ drivers rather than the 4″ I used for my big speakers; I duly bought some Monacor SPH75/8 polypropylene mid-bass drivers. I thought about using 19mm tweeters, but in the end plumped for the same Monacor DT25 as I used in my main system because of their small size, particularly the front flange. All pretty cheap.

The KEFs are stylishly covered in a fabric ‘sock’ that was no doubt very cheap to make, but I think looks good. (There is even the possibility of commissioning the very talented mother-in-law to make new ones in funky colours).

I removed the small plinth at the base of the speaker (four long wood screws) and peeled back the ‘sock’ from there to reveal a rounded chipboard enclosure and the three drivers – the Concord is a 2.5-way system. I decided that I would replace one of the 8″ drivers with my mid and tweeter, and that I should therefore invert the enclosure in order to keep all three drivers close together with the tweeter close to the top of the enclosure. I removed the two 8″ drivers but left the original tweeter in position as a ‘plug’ for its hole.

I dusted off the router and made two 18mm MDF flanged discs to replace the 8″ drivers. I should have made the flanges wider because they’re not quite wide enough to take a screw head and clear the necessary foam gasket underneath, meaning I’ll have to clamp them externally. I painted them to seal in the sawdust.

The SPH75/8 is troublingly difficult to mount for a one-off hand-made ‘rapid prototype’: a virtually non-existent flange from the front or behind, and a magnet that is almost as wide as the driver, meaning that if you mount it from the front, there’s almost no gap for the air to flow around unless you widen out the area around the driver from behind. It’s squarish, so if you mount it from behind but don’t want the full thickness of the baffle in the way, you end up having to accommodate the corners, which is fiddly without machining a complex-shaped recess. I ended up mounting the driver from behind, shaping the corners with a chisel. Next time, I will definitely find a woodworking expert to make the ‘plugs’ to my CAD designs!

I needed to make a chamber for the SPH75/8. WinISD told me it should ideally be 3 litres or so – but probably not all that critical for the mid range. I figured the easiest way to do it would be some 110mm plastic piping from the local DIY shop which is quite thick and fairly ‘dead’ if you knock it. I could even buy a ready-made fitting to allow me to plug the end. I duly made an assembly and fastened it to the rear of the MDF ‘plug’ using some bent aluminium brackets. I stuffed it with speaker wadding. The volume works out at about 2 litres, so not far off ideal.

IMG_0488 cropped

Mid range chamber made from 110 mm plastic pipe and end cap. Hopefully airtight by virtue of neoprene foam gaskets. It is stuffed with wadding .

Using self-adhesive neoprene foam and P-section draught excluder (this really does make a great seal), and plugging various holes, I rendered the mid range and bass enclosures pretty airtight. A top tip: hot melt glue is your friend. It plugs holes and gaps perfectly, and I have found that with a quick application it doesn’t seem to melt PVC cable insulation or ABS, so it’s ideal when you just want to feed cables through a hole in wood or plastic and seal the hole.

Crudely fastening it all together, I fired up one speaker to have a quick listen using slightly modified settings from my big system. I found it really interesting and encouraging, but when the bass drivers were played in isolation there was audible distortion. I worried that it might be the enclosures (they are made from mere 15mm chipboard), but I eventually narrowed it down to the drivers.


A modified KEF Concord. Those particular pieces of foam are just a temporary experiment, and would be too thick to fit under the fabric cover, anyway.

The mid and tweeter sounded sound spot on.

After building up the second speaker, the next stage was to set them up slightly more scientifically than before. I measured them (woofer near field, and mid and tweeter far field ‘pseudo-anechoically’) and applied roughly the appropriate correction to each driver (phase and frequency response, delay, gain). I also implemented bass extending EQ to aim for the same response as my big system(!) i.e. a 38Hz -3dB point. It sounded pretty reasonable, but I knew the bass drivers were not very good.

Next, I replaced the bass drivers with some cheap but much better Skytronic units (the same brand as my larger speakers). I made the appropriate measurements and compensations in the DSP, and raised the -3dB point to 40 Hz for the sake of reducing the power into the bass drivers.

I added some bracing to the most obviously flappy bits of the KEF Concord enclosures. Broom handle was much cheaper than dowel of the same diameter! The black square between dowel and enclosure is 1mm neoprene sheet. Dowel held in with countersunk wood screws from outside the enclosure.

Yes, the photos make it all look very ‘agricultural’, and the wide angle iPhone lens makes this bit of it look anything but square and perpendicular, but it is actually about right, and the speakers are solid, airtight, etc. where it matters.


Did the bracing change the sound? Can’t say, but it had to be done. I measured the driver in the near field again, and it hadn’t changed at all.

I re-fitted the fabric ‘socks’ – which I managed to get wrinkle-free much to my surprise.

finished KEF

A KEF Concord III with its fabric covering restored

As mentioned before, I ended up inverting the enclosures which meant that I had to remove the fabric ‘socks’ which were stapled very close to the ‘lip’ that is formed at the top of the enclosure. I was worried that I couldn’t find a staple gun that could get right into the corner of this lip, but in the end I found that an ordinary office stapler could do the job, which was fine. At the bottom of the enclosure, there are drawstrings which are pulled tight and tied off. The fabric stretches, so it forms a very flat covering.

The coverings are in pretty good condition for speakers over 37 years old, with just a couple of snags and small holes. They have faded from black to a very dark blue over the years which is only obvious if any of the non-faded material becomes visible through any slight misalignment. New coverings could be made in a variety of colours, but I think it would be preferable to retain the moderately coarse texture of the original material if possible.

Something that seems to have been an irritation to the previous owner is that the tops of the speakers are capped off with a square of hardboard covered with fabric, and over time these have warped, with the corners rising slightly. These have been re-applied by the previous owner using No-More-Nails or similar, to no avail.

In the end, I restored the fabric caps by carefully removing the material from the original hardboard, and stretching them over sheets of black-sprayed 2mm aluminium, fastening them to it with carpet tape. These now fasten to the tops of the speakers using Velcro. They look really good. I gave the pieces of cloth a rinse in warm water because they were looking a bit grotty, having taken the brunt of spilled drinks at parties over the years I imagine. It looks to me that it would be possible to give the whole fabric sock a proper wash, and it would survive OK.

I resprayed the wooden plinths with black satin paint, and the same for the 1970s speaker stands with casters.

I also decided to try the option of some of the original ‘inverted mushroom’ stands. I bought some of Mk IV ‘donor’ speakers, but unfortunately had to do a bit of metalwork to make these work with the Mk III. They now look ‘the business’, and I am very much enjoying their sound.

Scalford Hall 2017


I took my KEF Concords to the HiFiWigwam show in March. The room may have been smaller than last year’s, and I didn’t think the speakers sounded as good as they might. Nevertheless I found a few nice comments on the web.

Generally this year all the best sounding systems were active, with a system by “looper” which cost less than £300 with cheap drivers and FIR filters playing through a AV amp – leaving most high end speakers systems at the show in its wake.

Big shout out to Looper in room 232 who proved you don’t have to spend thousands to enjoy decent hifi. 

Looper in 232 had a similar home made set of filters driving the rebuilt Concords.  Better sounding than they were in 1975 I’m sure.  It was great talking to him about his thoughts and design ideas, and he managed it on a very tight budget.

All rooms were great but the things that got me going back for more –

…- Looper’s lovely KEF concord III

I was able to do the same ‘party trick’ as my other DIY system, where I showed that changing the crossover frequencies and slopes in real time – even quite drastically – had virtually no audible effect on the sound. If, however, we listened to, say, the mid range driver in isolation, the change was plainly obvious. I would say that this was what you would expect from a correctly set up system with not-too-bad dispersion characteristics, but most people had never encountered it before. The ‘trick’ depends on all the filters being calculated and implemented on-the-fly, and the fixed driver correction and in-room EQ being implemented as separate layers that are overlaid on the crossover filters. I think this demonstration is a kind of sanity check that your setup is somewhere near where it needs to be.

I can’t say why this is considered so unusual, but the fact that it is could go part of the way in explaining why most speakers sound a bit ‘odd’, and why speaker design is considered to be a mysterious art rather than a very straightforward procedure. It seems probable that the results would not be as transparent with a two-way speaker as a three-way because this introduces several new factors into the equation: significant driver beaming – a phenomenon that cannot really be corrected or neutralised – and issues with the drivers having to cover wider frequency ranges. Also, non-linear phase crossovers introduce “phase rotations” through the crossover.

[Last edited 30/06/17]



Vinyl just “for decor”

Maybe you suspected it all along, but an article in the Daily Telegraph suggests that 48% of vinyl albums haven’t been played one month after purchase, and that 7% of vinyl purchasers don’t even own a turntable.

Student Jordan Katende told the BBC: “I have vinyls in my room but it’s more for decor. I don’t actually play them. It gives me the old-school vibe. That’s what vinyl’s all about.”