Budget 'giant killer' speakers

Well, anyone who knows me and the shop, will know i have a love affair with vintage JPW speakers, specially the P1, AP2 and AP3.
It's just the way they sound, their sheer speed and  openness and most importantly their effortless ability of making music sound like music and not hifi.
The important and relevant point  here, is that they are not an exotic speaker, far from it, they can be picked up for a tenner, if the foam surrounds need replacing... in the right system and the correct room acoustic, they can sound truly 'High-End', capable of embarrassing speakers that cost many thousands of pounds.


So, this blog is going to have a look at other similar designs of the 70's and 80's that also have a bit of magic about them, another fave of mine is the AR range, most notably the 8 and the 18 but also including the 4Xa and the 7. As you might know, the designer of the early AR's founded KLH, which produced many fine designs, but for the purpose of this piece, we will pick the 317.


 So, in a nutshell we are focusing on speakers that share the following features:
 
 1) 2 way ported or sealed
 2) 8" paper cone bookshelf/standmount speakers
 3) Wide front baffle (wider than they are deep)
 4) Foam surrounds
 5) Simple cross-overs


Any one or combination of theses features could explain why this form of simple design works so well.

It's not going to be  a technical piece (apart from Richard Verney's bit) as I am by no stretch of the imagination, a Techy! It's Just a real world look at how these simple 'old school' designs may be just what you after if low to mid level listening in a smallish room is your chosen path.*

*(It should be noted, that these are small speakers and are not designed for Parties or for high-level listening, they excel in fluid midrange, imaging and focus, being at home with vocal and acoustic music)

Other notable candidates are the Heybrook HB1, Mission 700 MK.1 and of course, the wonderful smaller Peter Snell design, such as the K an the J.


All of these speakers have quite high Sensitivity and use large paper cones and quite low budget tweeters, paper ones in the ARs and 19mm vifa soft domes in the Snells, Mission 700 and JPWs (1 inch in the HB1) so there seems to be a blueprint here, probably back to the earlier Acoustic Suspension designs from AR, such as the 7, 4 and 3 (thought the AR3 is quite large and 3-way and not really in the same group) I guess they just worked, and other companies (mainly from the UK)  mainly ran with that ethos, thus shaping the look of budget to mid priced British designs of the late 70's and 80's.

Heybrook HB1

Acoustic Research AR18

Snell Type K

In the 70's and 80's, when most of these speakers were marketed, transistor amps were almost the only option, as valves were considered old fashioned and coloured by the 'Flat Earthers', mainly because the valve amps that were being used up to that point were mainly ancient Quads, Leaks and Radfords, that to be honest, needed a good service.... and it wasn't until the mid to late 80's with the resurgence of valve amplification from tube amp designers and enthusiasts, such as Tim De Paravicini, Peter Quortrop, Eric Anderson, Dave Chesil, Guy Seargent and others, that people started using these high efficient bookshelf designs with the then newly available valve amps. 


The new amplifiers were still mainly based on the old trusted Mallard, Williamson and other designs, but were of course made with new components and valves and were not tired out and 30 years old! noted valve amp brands of that period were, Audio Innovations, Audio Note, EAR, Edison & the Velleman Kits.

Mission 700 mk.1

Acoustic research AR8

KLH 317

So, the combination of the 2-way paper coned bookshelfs and the new wave of valve amps, just seemed to work, and continues to work today, even though these speakers were alsost certainly designed for budget Transistor amps, such as the NAD 3020, Creek 4040, Cyrus, Obelisk and Rotel...  and with Valve amps being very popular today, with affordable designs being  made available by companies such as Icon Audio, Puresound, Howes acoustics, and various companies offering kits for home building, valves are back with a vengence and these classic speakers can be picked up for pocket money, so now's the time to have play and discover the joy of bargain basement speakers that will open your eyes as well as your ears!!

I have feeling that if I cover the specs and merits of the speakers mentioned, this blog will go on for pages, so instead, I urge you to pick up one of these design, probably for next to nothing from a famous on-line auction site or from a event such as the Audio Jumble and have a listen for yourself.

Next time I have a 5 minutes, I may do a bit on say, the JPWs or there ARs, but for now, i'll let good friend and audio engineer Richard Verney tell you about his pair of KLH 317 speakers he picked up from me for a mere £70, they even had their original boxes!! All i had to do was fit a set of new 10" foams and they were ready..

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The KLH 317 speakers revisited by Richard Verney (pt1)

The KLH 317 are a decent sized stand mount speaker with an 8 inch paper cone bass driver, and approximately 2 inch mid/tweeter. The crossover is a fairly simple design, of the type where the two drive units are in series, and bypassed by L and C for tweeter and bass respectively. The crossover response is something like this:-

The construction of the speakers is shall we say, ‘budget’, however, the performance is startlingly good. One can guess if this is because they perhaps use low distortion alnico magnets, the paper cones, or the choice of a low crossover frequency with a larger than average tweeter. Whatever the exact magic is, they offer transient response, and ‘speed’ better than most modern plastic coned, ceramic magnet, small dome tweeter designs. Once you get over the idea that such tatty old speakers actually sound this good,  it becomes worthwhile to tweak away weaknesses. For the KLH, I upgraded the crossovers with Mundorf Evo Aluminium Oil capacitors from Hifi Collective: http://www.hificollective.co.uk/componentshome.html , replaced the terminals, and also got rid of the insane tie-wrap holding the inductor down, which was preventing the screws clamping the terminal plate to the back of the speaker cabinet properly – it went through one of the screw holes.

I braced the cabinets crudely with hot melt glue and some wood offcuts, and put in about twice as much wadding inside the cabinets as previously. Dedsheet was added to the bass driver metal frame, and around the toilet roll style bass reflex tube. I did try some dedsheet on the cabinets, but feel this adds mass without providing much damping, the net result being a cabinet which just rings longer at a lower frequency than before – the desireablity ( and audibility) I was unsure about – so ended up not doing anything to the cabinet walls apart from the bracing. Next up I want to pad the tweeter down with a bit more resistance – the sound is too bright at the moment, and also do my normal trick ( adopted later by Wilson, and also seen on BBC LS3/5a) of putting some felt on the front baffle around the tweeter to reduce ‘splashyness’. Here are some pictures of the bracing, damping, and extra wadding: