Transmission Line for or against?

[DJ Sense]

Hi I'm very new to the world of diy hi-fi, but after seaching it seems most things seem possible!, i'd just like to know your views as i'm thinking of building a pair of TL speakers, I like a fairly flat response, but have'nt as yet heard TL!

Thanks

[Scottmoose]

You can get a flat response from just about anything if you try hard enough. Go for it though. If you want a versatile box speaker, there's nothing to touch them.

Go to www.quarter-wave.com for Martin King's many superlative articles and seminal MathCad sheets. All you'll ever need to design your own TL.

Best
Scott

[BobEllis]

From what I've modeled in Martin King's worksheets, a MLTL gives the smoothest upper end response. However, the ripples in a regular line's response (measured as predicted in the lines I built) don't seem to be audible. Just don't get fooled into thinking a MLTL is just a ported box.

[rjb]

I presume you have read up on the different types of enclosures, so know the basic differences and how they work.

The basic sound of an complete speaker is controlled by the drivers, and how the designer has used them so its difficult to compare just enclosures without fixing all other parameters.

However as a general statement, well designed TL's tend to appear to have less bass than say a Bass reflex, (may seem bass light), but this is because it is cleaner with less overhang. In fact the bass rolloff is slower so they usually go deeper. The mid range also seems cleaner. The downside is they are bigger, and more complex to construct.

Don't forget that room gain tends to increase the apparent bass, which can be good or bad, depending.

I like them

[DJ Sense]

Thanks guys, had a look at the website scottmoose looks possible!, although i don't see at present how one full range driver in an enclosure can be as "clean" as two or three (or is that part of the design that i'm not getting, bearing in mind i'm only used to large bass reflex designs PA wise!)

[Scottmoose]

It depends on your definition of 'clean'. Like any subjective evaluation, it means different things to different people. Some use it in reference to a lack of crossover distortion, coupled with crisp definition of transients etc. Others suggest it is a 'smooth' sound, without audible cone colouration, others... you get the idea.

An FR dynamic driver will never be as flat, objectively, as a multiway, which is hardly surprising, given everything you're trying to do with a single cone. It really depends on what subjective qualites you most value, or annoy you the most. For me, it's crossover problems. I've no problem with crossovers to be honest; the trouble with them is, there aren't many good ones. So I'm willing to accept a few other compromises, which don't annoy me especially, in order to circumvent the one that gets my goat, and reap a few other benefits too.

Martin is the man who's done the most work on TLs. It'd be a very brave man (or a fool) that ignors it. That isn't just ye olde rule of thumb that's one his site, as you can see. TLs don't necessarily have to be more complicated to build than a regular BR box -the MLTL for example looks almost exactly the same for example, though they don't operate in the same way. So don't let that put you off. If you fancy the traditional tapered sort, first stop is to read Martin's new Anatomy of a TL article (yes, there's a lot of maths, but he's done it all for you, and it's easy to follow), then his Classic TL Alignment Tables, which will give you a good starting point. Try to go for a smooth, graduyal roll off below 100Hz to keep in step with room-gain, or you'll find things start to get too bass-heavy, as rjb notes. For reference, near corners, you'll get about 6db of lift, near a rear wall, about 3db. Depends ont he room, obviously, but those are the approximates.

Hope this is of use
Scott