Hi,
Ply is always odd numbers of laminates because even numbers will
inevitably warp, the obvious case being 2 ply which is clearly asking
for very serious trouble compared to no ply's, though its fair to say
as the number of layers increase it becomes less of an issue, but
there is never a case for making even numbered ply, so they don't.
Its also clear for 3 ply stiffness is highly asymmetrical, and again its
fair to say the asymmetry in stiffness reduces with layer number.
3 ply is less asymmetrical than a single sheet of solid wood, and
far less prone to warping. 5 ply exists in all sorts of forms with
different woods and layer thicknesses. 7 ply less so, etc. ....
Marine ply, which is the strongest and usually 7 layers plus is not
necessarily the best ply for speakers due to its density. In speakers
the strength is not needed and lower density thicker ply can have
far higher stiffness to mass ratio, due to the cubic extra thickness.
rgds, sreten.
Butting in here, sorry, chaps. Just built a pair of LS3/5a clones using the Monacor/SEAS combination mentioned several times in this thread. Linkwitz 2nd order crossover, lpad to attenuate the tweeter, but somehow doesn't sound right - far too forward, and the midrange isn't as nice as I'd projected.
Going to do a rebuild anyway, owing to not having found birch ply here in France, but can anyone help with the crossover? Aiming for the Harbeth sound, but its a mile off at the moment.
Going to do a rebuild anyway, owing to not having found birch ply here in France, but can anyone help with the crossover? Aiming for the Harbeth sound, but its a mile off at the moment.
Not butting in at all, avole! Sounds like you are ahead of most of us. Based on the spec of the Monacor SPH-135/AD midwoofer, I'd guess you want about 1.5mH total bafflestep inductance and a trap at 1.5-1.6kHz. A Zobel on the 98mm SEAS 22TAF/G metal tweeter seems standard practise and Troels uses roughly 4.7R/1uF.
I've aimed for 3.5kHz crossover here on similar drive units but allowed for the 0.47mH inductance of the Monacor. You'd change the 6.2R resistor in front of the tweeter capacitor for level matching and the 12uF could possibly be 10uF, but this looks about right to me. A start anyway. Without the trap in the last image and with 1.5mH instead it looks a bit forward on vocals which may be what you are hearing. 🙂
I've aimed for 3.5kHz crossover here on similar drive units but allowed for the 0.47mH inductance of the Monacor. You'd change the 6.2R resistor in front of the tweeter capacitor for level matching and the 12uF could possibly be 10uF, but this looks about right to me. A start anyway. Without the trap in the last image and with 1.5mH instead it looks a bit forward on vocals which may be what you are hearing. 🙂
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May be that some time is needed to break in. It probably won't sound right from the start. The same applies for "real" LS3/5a.
@system7 Thanks for the info was thinking about adding the trap. I'm going to do a rebuild anyway, this time with birch ply (assuming I can source it here in France) , so not really that far advanced.
@ivanlukic been running them for over 100 hours. The sound did improve, but still too forward. I think the crossover design is most of the problem.
@ivanlukic been running them for over 100 hours. The sound did improve, but still too forward. I think the crossover design is most of the problem.
I am not sure that obtaining birch ply is that much worth the effort. Most BBC designs date from late 60s/early 70s so they tried to make the most from materials that were readily available then. A friend of mine built LS3/5a from Wilmslow kit 20+ years ago and used 12mm ply for sides and 9mm front as described in instructions but had problems with KEF drivers that were substandard in quality (although original B110 and T27). So all the efforts concerning cabinets were in vain. Since original drivers are not available, and you must use different drivers, I am inclined to think that emulating cabinets will probably be waste of time.
Although Harbeth still use thin wall construction (BBC style) I am in doubt if the sound of their products is that much owing to it. I think that drivers used and crossovers tuned for particular loudspeaker have more to do with it.
Although Harbeth still use thin wall construction (BBC style) I am in doubt if the sound of their products is that much owing to it. I think that drivers used and crossovers tuned for particular loudspeaker have more to do with it.
There's a publication , also available in PDF
AUDIOCOSTRUZIONE
that explores the making of the legendary LS3-5a
The drivers are modern though the woofer is still mounted on the back of the baffle.
I did a research and the crossover and dimensions are published in Nr.4
(Buy>>old numbers )
The remake is made by the people of Audiomatica , creators of the CLIO measurement set up
AUDIOCOSTRUZIONE
that explores the making of the legendary LS3-5a
The drivers are modern though the woofer is still mounted on the back of the baffle.
I did a research and the crossover and dimensions are published in Nr.4
(Buy>>old numbers )
The remake is made by the people of Audiomatica , creators of the CLIO measurement set up
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I know. But we looked at the Audiocostruzione LS3/5A clone earlier. 🙂
In English with crossover in Diffusori DIY, Due Vie if you look around:
Audiocostruzioni - Il Portale dell'alta fedeltà amatoriale
A nice plywood build of the same, worth looking at for the photos of the woodwork:
Audiocostruzioni - Il Portale dell'alta fedelt amatoriale
This is basically a 1st. order crossover with Zobel on the woofer. Not so acurate, but lively sound I'd reckon. Troels would be aghast at the unrebated tweeter. 😀
AH ah ! You missed the important E and not I at the end of the name ...one is a portal ,the other is a magazine . 11 € You'll be asked to view the PDF 😀
I've found a Visaton 5" 0.6mH paper driver that will fit the Falcon Acoustics plywood cabinet with a slight issue on the bass fixing screw holes but you could fill those with a bit of wooden dowel and redrill them, I reckon! 😎
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
The Visaton W 130 SE 8 ohm. It's really a W 130 S in a different chassis, and you can model it just like a W 130 S. I did this (rough) modelling in Boxsim with front mounting on the baffle as a 5 litre standmounter with a 1.4kHz trap and it all worked out nicely. Looks easy to adapt for any tweeter you fancy to me. 104mm would be ideal. It's hard to source in the UK, but I expect you could get it easily enough from the continent.
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
The Visaton W 130 SE 8 ohm. It's really a W 130 S in a different chassis, and you can model it just like a W 130 S. I did this (rough) modelling in Boxsim with front mounting on the baffle as a 5 litre standmounter with a 1.4kHz trap and it all worked out nicely. Looks easy to adapt for any tweeter you fancy to me. 104mm would be ideal. It's hard to source in the UK, but I expect you could get it easily enough from the continent.
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yes the 'SE' is almost the same as the 'S8'. Im a little lost to why anyone would want to mount rear of the baffle though, unless out of necessity.
Re-reading I gather it is a necessity. Apologies
Re-reading I gather it is a necessity. Apologies
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You have probably seen this page before, but Ive had these drivers a while.
I like Mark's approach to his build (in the main).
It doesnt use a 5" driver (but was the B110...really?)
Its a cute little thing, of very similar proportions.
Audax Mini-Monitors
Sadly Zaph's link to his mini monitors has long gone, But Vikash has a good write up of run in testing.
I like Mark's approach to his build (in the main).
It doesnt use a 5" driver (but was the B110...really?)
Its a cute little thing, of very similar proportions.
Audax Mini-Monitors
Sadly Zaph's link to his mini monitors has long gone, But Vikash has a good write up of run in testing.
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I have two Rogers Studio 3 cabinets and two grilles. The cabinets look very much like that of the LS3/5a, with bitumastic pads fitted to the walls and similar foam lining.
I can't make up my mind if to make a pair of small loudspeaker with them, or go down the LS3/5a path.
I would appreciate any guidance from Forum members on the path they have taken. Previous posts in this thread are useful to read, but it would be good to have any other ideas.
I can't make up my mind if to make a pair of small loudspeaker with them, or go down the LS3/5a path.
I would appreciate any guidance from Forum members on the path they have taken. Previous posts in this thread are useful to read, but it would be good to have any other ideas.
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I am listening to a pair(you need to supplement them with a subwoofer) NOW....For about US$350 at Meniscus it's good value.
Continuum crossover kit?
Jeff Bagby made a decision to keep the Continuum crossover design proprietary for commercial purpose. I fully support his decision. There are many sources of the whole kit.
But if the builder wants to get their own drivers to do customized matching etc. There is no source for the crossover only kit yet. It would be nice to have a commercially available PCB for the crossover too.
I found a PCB on Ebay that may work well. I used 2 pairs for the 4 bookshelf I built. This PCB may be a good fit for the Continuum crossover design too. They are not cheap at $26 a pair, but the quality is excellent.
Jeff Bagby made a decision to keep the Continuum crossover design proprietary for commercial purpose. I fully support his decision. There are many sources of the whole kit.
But if the builder wants to get their own drivers to do customized matching etc. There is no source for the crossover only kit yet. It would be nice to have a commercially available PCB for the crossover too.
I found a PCB on Ebay that may work well. I used 2 pairs for the 4 bookshelf I built. This PCB may be a good fit for the Continuum crossover design too. They are not cheap at $26 a pair, but the quality is excellent.
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This is a really good thread with the parts I've read so far. But without reading the entire thread and with the bits I may overlook or neglect. Box aside which is pretty self explanatory what are the most cost effective drive units to make a respectable sounding LS3/5A ? or better perhaps.
The thing is the combination of the T27 and B110 did do something magical together which only those can really do.
The other thing is a crossover. Again without going down the exact replica route any respectable off the shelf 2 way crossovers that you could just mount into the LS3 type sealed box without any modification to get you nice results? And just something would do, no need to get too particular about anything. There is no exact/right way anyway I feel, if there was there wouldn't be 1000s of different types of speaker models as they all sound different 🙂 So the cheaper the better would be nice.
The LS3/5A are such a great sounding speaker at what they do well though but unless money no object or you just have to have one, they are way overpriced.
The thing is the combination of the T27 and B110 did do something magical together which only those can really do.
The other thing is a crossover. Again without going down the exact replica route any respectable off the shelf 2 way crossovers that you could just mount into the LS3 type sealed box without any modification to get you nice results? And just something would do, no need to get too particular about anything. There is no exact/right way anyway I feel, if there was there wouldn't be 1000s of different types of speaker models as they all sound different 🙂 So the cheaper the better would be nice.
The LS3/5A are such a great sounding speaker at what they do well though but unless money no object or you just have to have one, they are way overpriced.
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I always thought the secret of the natural voice reproduction of the BBC LS3/5A, and I have heard the Chartwell version, was that it used 90 degree phase alignment . Which avoids the power hole in phase aligned designs.
I can't prove this because I don't have the exact modelling, but many fine BBC designs at Mark Hennessey's site:
Hi-Fi › Rogers Loudspeakers
Various versions of the BBC mini-monitor varied on tweeter polarity. I am thinking of some of KEF's derivatives. But you are allowed to do that with BW3.
I can't prove this because I don't have the exact modelling, but many fine BBC designs at Mark Hennessey's site:
Hi-Fi › Rogers Loudspeakers
Various versions of the BBC mini-monitor varied on tweeter polarity. I am thinking of some of KEF's derivatives. But you are allowed to do that with BW3.
That looks another interesting LS3/5A link, will have a look through that.
But the main thing is how do we build a cheap as chips one?
And ah done, read this thread. Some great info on here. I like the gentleman's approach who changed the drivers as well. He started out by changing the T27 which he accidentally blew listening to Mike Oldfeild which turned into a positive change, and with a titanium dome as well. Also he went further and did the bass drivers and never looked back. Very interesting!
Lots of discussion on which Monacor 135 to use as well. AD TC or whatever, they do a carbon cone one now as well wonder what that be like? I know there's also a kevlar but going on the many kevlar speakers I've heard I didn't think kevlar would be one I would choose to install in anything. Not bad just not for me.
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