The BBC LS3/5a, a voice still to be reckoned with.

The LS3/5a a voice still to be reckoned with.

How many of you own one of the various incarnations of this great little speaker. Though never owning a pair myself I have known may people who have. I always marvel at the "natural" portrayal of vocals and mid range in general through these speakers. Also how many truly great speaker manufacturers made this model.

For those of you not familiar with this integral bit of audio history check out the following site:

All about the great LS3/5a

 

Gary: if you're handy with woodworking, build a pair! A long time ago, I'd read an article about someone who built a replica using the proper KEF drivers and crossover.

 

I'm told my 3D Acoustics 3D6/10B satellite/subwoofer combo was a New England speaker manufacturer's American answer to the LS3/5A's. The added bass module let the satellites reproduce the full spectrum with more (but not all) of the authority Steve talks about regarding full-range speakers.

I've never heard a pair of LS3/5A's, but if there's any family resemblance there, they must sound very sweet.

 

A couple of companies have made companions LS3/5A subs. Thing is, I've heard very few sub/sat systems that really properly mesh their sound together. Not talking about full-range speakers where sub augments the main speakers, but some of the M&K systems I heard many years ago sounded good, but a bit disjointed.

Nothing as bad as a Bose Acoustimess system, though...

They're not in the class of an LS3/5A, but I really like the big sound I get from my little Boston A40's.

 

Are good, sought-after speakers like this and others (JBL Century L100, Large Advent, KLH Model Six, Boston A40, etc.) lucky engineering accidents or were they designed that way?

I don't know of any modern speakers (yet?) that generate so much excitement.

Since speakers are now designed with the aid of computers & other sophisticated test equipment--rather than solely by ear like these classic speakers--could today's models somehow be TOO good? I don't know--I've heard the Large Advent and another well-thought-of speaker, the Genesis Physics Model 210. For "old, low tech" speakers they sure sounded good!

Or could this simply be a pleasant trip down Nostalgia Lane, and yesterday's speakers really aren't that great?

[T]

 

If I were setting up a "Kitchen System" They would be my first choice along with a really good hi current Brit integrated and a decent CD player. This would provide great "non-fatiguing" sound that could be listened to at "background and moderate" levels over long periods of time.

 

Khorn: I'll have to say that I have three pairs of Boston A40's, two of which I've replaced the foam surrounds on. Considered selling them, but I like them too much. Perfect for remote locations. One pair sounds great, but the cabinets are a bit scratched. No big deal--I use these out on the deck in the summer! For a couple of months, I had one pair of the A40's hooked up full time...never was fatiguing at all, and sounded good at lower volume. One downer was that I'd replaced the dust caps on one of the pairs. My kit came with both paper and plastic dust caps, where the originals were a cloth cap with an open weave to it. No problem at lower volumes, but I can clearly hear a difference, a sharp peak between 2kHz and 3kHz.

Gary: you could probably make a nice pair of speakers with those KEF tweeters. But a true-to-BBC-spec LS3/5A has specific requirements--the KEF woofer (B110, I think?), the crossover, and even the type of wood used in the cabinet. That link Khorn gives above points to a site that even has links for plans to build an LS3/5A.

If you're just out to build something to see if you can do it, and what the results are...and you're *not* that handy with the table saw (such as, those three stumps where your fingers used to be ), a couple of the speaker suppliers sell pre-made cabinets that may need nothing more than gluing and clamping to assemble. I could look around, but there may even be some freeware programs that will calculate box dimensions for the Audax drivers you have. (BTW, the original Boston A40's used a round Audax tweeter.) Depending on the type of sound you like, and size of box, it may determine if you go with vented vs. sealed. Sealed systems require a "looser" (more compliant) woofer suspension to overcome the sealed volume of air in the cabinet. With vented, you would need to calculate a correct port length to tune it...I had a set of formulas around here from an old issue of Speaker Builder. A couple of places I've bought from in the past:

http://www.madisound.com
http://www.partsexpress.com

Taurus: yes, the speakers were designed that way. But I'm sure all of the prototypes and experimental models had a lot of "accidents" in engineering. I know the idea behind the "acoustic suspension" was Kloss's idea, where you had a woofer with a very loose suspension to it; the idea was that the sealed air in the cabinet would support the speaker, providing something like an air spring. The volume of air (box size) would determine the bass response. Too large and the bass would be weak, and you'd damage the woofer. Too small, and you lose deep bass...or you need a smaller woofer. So there is some engineering and a lot of experimentation involved. It's what a lot of us "amateur" speaker builders do when we put a system together. I've never built anything "big time" other than a subwoofer for the car, and converting some old Realistic cabinets from a sealed to a vented system with new drivers.

 

Rudy-Rudy-Bo-Boody is co-rect about EVERYTHING having to be exactly to spec - very, very close tolerances for EVERY aspect of that speaker has to be met (drivers matched to within a .5db or so range if my membory holds true, preferably from the same batch). Boy, I wanna dig out those boxes full o' Speaker Builder mags I got stashed away (got 'em all from start to early 90's) - that's a lotta fun, speaker DIY!!!

 

You certainly are the Anglophile when it comes to speakers - got any American speaks that run in the esteemed league with yer Brit boxes???

 

That's why I like their "big brother", the Spendor Sp 1/2. They've got a lot of the Ls3/5 magic!!

 

Way to go Steve, when did you finally break down and by a pair?
I've got the Stirling BBC versions, Rosewood cabinets, just kidding........

For all members with very little space and can't spend a fortune...................................These could be the answer for you.
Soundstaging and imaging like you'd never believe.................

-Wes

 

Same here! I may take the plunge and build my own surround system, if I don't do an all-Boston Acoustics "A" series system. I have a stash of some of the earliest Speaker Builder magazines. I always wanted to build those electrostatic speakers, but never could find the thin plastic film they used...it was either a misprint, or it was a thickness that none of the plastic supply houses in town had ever heard of. I have the 13,000 volt power supply I salvaged from an old copier.

IIRC, one of those issues went into detail on the LS3/5A. Even if I didn't build anything, there's a lot of good information to be learned from those articles.

I wonder which subwoofer design would go well with those LS3/5A's? Transmission line?

 

I'd look for a box design using that crazy almost oval shaped KEF woofer (was it the 139)???

 

Something like the Rogers AB1 works; scroll half way down this page for more details.

http://home.freeuk.com/pwhatton/lstips.html


cheerio

 

Hmmm...doesn't say what cabinet type the AB1 is. I was thinking if the sound was clean and detailed in the LS3/5A, a quarter-wavelength transmission line might be a good match.

Interesting about using the AB1 as a stand...or not!

 

Hi,
If anyone wants to part with a pair of LS3s here in Toronto, I am your man!
There is an LS3/5a list group on Yahoo which I understand just had a two month discussion concerning the merits of blue-tack and its usage. A number of fellows there have built their own. Crossovers can be a little hard to come by and is hard to replicate due to its complexity. That said, I understand that new LS35/As (with TV shielding!) are soon to be re-introduced in the UK by one of the old licensees. Jeff

 

Jeff,

Have you checked out Stirling Broadcast's line of LS35A's?

I bought a pair from Doug Stirling.........wonderful little gems. Doug is a nice guy too.

-Wes

 

Hi Wes,
I haven't. Thanks. I didn't know there were any in current production as I had understood the original parts to be in short supply. Do you know if they have a North American distributor? Jeff