Wad Kls3

This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Done a search but can't find anything that will help me.

I have a pair of World Audio KLS3 Gold loudspeakers and am looking at rebuilding the cabinets. I'm considering going for 3 separate boxes and would like some advice about how I determine the internal volume of each box. Is there any merit in leaving the rear of the midrange unit open? Also, the 3 drivers are located very, very close together in this design. Will the sound be destroyed by using separate boxes as I don't see how the drivers could finish up as close together as they are now.

Replies will be appreciated.


open back to mid range may be a good solution.
Try a 2way satelite confguration for mid & top, then a separate box below for the bass.
I think it is right to keep the treble & mid as close together as possible. You might also benefit from making the mid box very narrow but deep with generous radius on the front corners.
You could also try 2 bass units in a 120 to 130 litre box for more bass power. I think this speaker needs it for bottom end extension when playing at higher volumes.
In contrary, I think you could benefit from making the baffle much wider and less deep :) This will help with wavelaunch in the vocal range and I think it seems to give a bigger, more lifelike sound.

The mid and tweeter should be as close as possible, but there is an amount of scope to move the bass away a bit. Doesn't the design already have a midrange cavity? To make separate boxes for bass and mid+treble simply make the bass box the same internal volume as what it is now. The midrange box can be whatever volume you like as long as it's bigger than a couple of litres.
I know the KLS3 Golds well, and rue the day Audax stopped making that quite wonderful tweeter. A sad day for audio.
Some thoughts however, begun with a query: why the multiple box approach? Noel designed these beasts properly (i.e very well), and you won't get much better in my view. I ran a MathCad sim a while back and couldn't really improve upon it at all as a vented box.
Assuming you go with the multiple box approach, imaging won't be destroyed if the drivers are spread further apart, but I suspect it won't do it any favours either -that bass-driver is crossed too high for it not to be audable.
What might be an interesting way to go would be to rebuild as a MLTL. Wouldn't affect the bass, but the mids and highs would be to die for. The box would be a bit larger, but it's be worth it though I reckon -these were among the very best speakers I've ever heard -the drive-units are glorious. I just wish World Audio Design would do some more and twist Audax's corporate arm into reintroducing that tweeter! (and if pigs had wings...)

Thanks for the replies everybody.

Scott, What is 'MLTL'

Regarding the principle idea of splitting into separate boxes...it's just something I imagine might make the speaker sound even better than it does now. I'm not unhappy with it at all, but the cabinets do need to be rebuilt. I bought these second hand as a ready built system with the idea of using the drivers and rebuilding to my own taste. I'm moving house soon and will be able to put them in a room 22' x 12', they'll have to be taken apart for moving and so this seems like a good time to rebuild. The current room is 14' x 11' plus a bay, I think they'll be better just for the larger room.

On that basis, I wouldn't split them; the problems I reckon will outweigh the benefits. So long as you brace them properly and use at least 18mm MDF, cabinet resonance won't be a significant factor -you can always double some panels too.

As they need rebuilding, I'd either construct a new cabinet to the original design, or take a walk on the wild-side and go down the MLTL route.

What is an MLTL? It's a Mass Loaded Transmission Line. This is a term coined by Martin J. King, the man who finally, using some heavy math, cracked the mysteries of the transmission-line cabinet. Now, I'm not thinking trad tapered lines here, which make most people run for the hills (justifiably -most are rubbish) but a straight line. Internally, it will resemble a straightforward vented box, and is just as easy to build, but it doesn't work in quite the same way. In a TL, the dimensions and drivers are positioned so as to promote quarter-wave resonance within the cabinet. This is a subtle but critical shift over the normal vented box. A degree of stuffing is normally used, which damps higher harmonics (not something a normal vented box can do). You get a beautifully pure mid with a decent TL, and deep, smooth well-damped bass without many of the problems associated with conventional reflex loading. Have a look at Martin's site, and download his MathCad worksheets if you can: well worth doing. You'll find it at

Unless you're up on math, it looks frightening, but the concepts aren't actually too difficult once you've read a bit, nor are the worksheets -remember, Martin's done it all (math-wise) for you -all you need are the driver parameters, plug them in, and play around with the dimensions until you hit upon the best compromise. This is serious software BTW. One of my favourite tricks is to use it to illustrate just how bad most well-regarded commercial designs are / were. Another site worth a look is Bob Brines'; single driver speakers, but he has a very good section of essays on TL design which are easy to digest and help beginners understand some of Martin's MathCad worksheets, and where to start with them. You;ll find it here: http://www.geocities.com/rbrines1/

Drawbacks to the MLTL approach? Well, the box will end up slightly larger than the original -a TL is invariably the largest type of cabinet, except for horns, but with these drivers? Worth it. Stunning system like no other. Worth thinking about at least.

This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.