Nice little TL's Cost is small sound is big.

[farmerjack61]

Hello from Tasmania where it is mid winter and the frost is thick!

Here is a speaker design that should work with any drivers you can throw at it - don't bother buying the expensive ones, just salvage some drivers from those little all-in-one stereo's and poke 'em in the holes. This will give you the general idea and a 'taste'. You will need to find four four inch full range or mid-range drivers as well but again, dont buy the expensive ones unless you can afford it, mine cost nothing because they came from a TV monitor. The tweeters I used can be purchased from that auction website for $25 a pair of Vifas with the little heatsink on the back. I guarentee if you do it right they will surprise even the most sceptical critics. (I can help with the crossover design and some dimensions if you need).

I will post a couple of drawings:

OOPS can't post Cad files!

Just download the photos and then print them onto a sheet of graph paper to get your dimensions.

I will show some gifs of the general shape and the simple porting system. I can thoroughly reccommend building a Transmission Line or Quater wave speaker - BTW my bass port is not exactly 1/4 wave length but still sounds bigger than it looks.

[enigmaticEntity.]

Well, it does look interesting, I like the layout of drivers. Post some pics when you build it ;-)

I also have some drivers from second hand shops, but not 4 of a kind

[farmerjack61]

Hi there you Tassie Devil! Me too, Devonport. I really hope you don't live in Hobart Enigma. My sister is down there in FurnTree and it's been snowing again. I hate the Winter in Tassie.

The speakers: I have known about these TL designs for some time and thought they were just an excuse for using small drivers, how wrong I was. This particular one sounds neat. I guess everyone's hearing is different but I have had a few 'WOWS' from my mates. Those same fellows have listned to some of my larger speakers and we all agree that inch for inch they sound just as good or better than, say my sound dynamics or goodmans magnum speakers which take up a lot more room and are very heavy to carry when you move house.

The woofer I am using at the moment came from the auction site for $33+$10pp type in DME 6.5" Woofer Mid. Jaycar have some nice little 4" replacement speakers also, they dont have to handle a lot of power because you can hook them both in paralell and use appropriate X-overs.

I have a lot of respect for the 3rd order crossovers because they use a much smaller part of the audible spectrum. This means that the drivers 'share the load more evenly than the lower orders, but one always takes over before the next cuts out. When designed properly you can test them out with a simple wave generator and actually audibly hear the change from one level (and driver) to the next, and it is always bang-on the frequency used to make the crossover.

There is a picture of the finished product here:
Engineer, help please - Neg. feedback/infilters

They are the skinny black towers, with the pearlescent pinkish middies (I'm colour blind so they could actually be any colour between white and black, but they look like the colour of a pearl), - I'm afraid the paint job was a bit of a failure, but they still look great to my ears.

Its been great chatting to a nuther Tasweigan, nice to meet you, bye for now, Phil E.

[farmerjack61]

There is no reason why you couldn't do the same thing with a woofer and a tweeter. A two way system. Yea, even easier, do away with the top cavity and THEN you have more volume for the woofer. The vent from the bottom of the woofer box around the back to the top will remain the same but you don't have to use as much timber and therefore is EVEN EASIER TO BUILD.

The speakers are roughly 750 high x 200 wide x 300mm deep. But of course a few cm either way wont make too much difference.

Crossovers would be easier to build also, as there will only be two coils to wind if you like the 3rd order type.

Anyway, enough jibberish for now. Cheers

[pcb121055]

Not meaning to be impolite but why does this not look like a TL configuration to me ? I am used to transmission line enclosures having tapered paths. I think I see two reflex enclosures: one for the mids and one for the woofer. am I wrong ? and if they are reflexes, why wouldn't the driver characteristics play a role ?

[enigmaticEntity.]

Jack, I do actually have a build going at the moment, using the Dayton rs-100 and Vifa ox20. Got these from Darcher Audio in Launceston (He orders from Parts Express, but gets cheaper shipping so if you ever need new stuff from PE...)

I had help to design the transmission line, and it should sound very nice when built. Here's a 3D model of what the speaker will (hopefully) look like, note I haven't shown the tweeter...

I live in Hobart on top of a hill next to Mt.Wellington, so it is cold outside

Edit: pcb121055, I think you can have folded, untapered TL's, though Jack's is sort of like a hybrid(a bass reflex with an ultra long port). Ported enclosure for the mids in this design is almost redundant, since there is a larger woofer to cover the bass, and mid-enclosures usually have a lot of stuffing in them anyway. I'm guessing if a person doesn't have measuring equipment and only has lots of cheap/unknown drivers, then the design would work quite well. In Tassie it can be tempting to get cheap unknown drivers, since PE is over the other side of the world, and Jaycar's offerings of Vifa, Hi-Vi-like drivers are quite expensive (relatively).

I got all my drivers and most crossover components from Darcher Audio for about $100, since some were on special right when I ordered them

[pcb121055]

thanks for the response, enigmatic entity. I see reflexes. that configuration has two very distinct vibrational modes but I don't want to rain on anybody's parade. enjoy your builds and i hope they sound great.

[planet10]

One would need to model this to see where it lies on the continuum between TL (a daline in this case) or a small BR tuned really low.

If one damped the line/vent it would become an aperiodic box of some sort.

I suspect performance of the box will vary dramatically depending on what driver is used.

dave