Another set of mt121 on the way

studio 45 been reading about your project
www.speakerplans.com/forum/forum_posts.asp?TID=18295&PN=1
nice work on the horn.
Do you or would you share the dimentions i might be tempted to have a go. Thinking of making a template and casting two from it. love the agressive look.

deadbeat i cant thank you enough ill be loving that, though as i cant get hornresp or akabak to work on my pc, ill have to ask, will you need different modeling peramiters if you were to use the mx600 style smoothing from the straight exponential sides around the driver? (as in studio 45's incarnation)

it's based on the dimensions of the limmer 042. i never write owt down so can't remember them exactly. there is some arbitraryness in the design as well, the height of the 6" section is not given on the 042 so I guessed, and chose a 12 degree flare rate for the vertical, to match the mt flare below....more for aesthetics than cos I knew it would do something! They are definitely still a work in progress, i am going at it ASS style with the car body filler and the elbow grease, trying to get em to sound better, measure better or both When i feel i've reached some kind of end point, i'm gonna make fibreglass moulds, (and put on a massive party, of course).
Yes and while I'm at this, could someone, for the love of God, please write a horn modelling program for the Mac? I'm mining without a lamp here, and buggered if Widnows is getting anywhere near my hard drive...

Studio45, I have exactly the same problem. I only have access to my windows box at certain times (which is where all the programs live...). I reckon you should PM David McBean on SP about whether Hornresp is suitable for use in Darwine (a project porting Wine to Mac). If all else fails, there's always VMware...

About your horn, I've just had a closer look and you have created...a waveguide it seems (no compression at the throat). Good stuff, I have a soft spot for a nice waveguide. About the ASS way, I'm not sure what Tony uses but I'm experimenting with Slick Sand, which primes, seals, and fills all at once, and as the name suggests, is easily sandable.

sks01...I don't think you can fully model that throat bit if you go about it that way, even if it does give good results, as the sides aren't exactly exponential, are they? If you wanted to model a horn with an exponential bit around the throat, you just split the waveguide into two sections, the first being the exponential area (you plug in the axial length, flare rate, cross sectional areas, etc), then the next section will be a conical bit. I'll be going with an actual horn for the model as opposed to a waveguide, with a very small front chamber as in the MT12 sections. The horn mouth should cover the entire front, coupled with the dispersion, the horn's design is nearly done! I also think you should either post in diyaudio on david's thread about a hornresp running problem (he appreciates all feedback so it can be incorporated in the next version), or PM him on SP.

While we're on the subject of fiberglassing again, I would add one thing. When you have a satisfactory shape in your prototype, and you are ready to mould your first pattern or plug, as some people call it, make sure you brace the inside after laying up several layers of glass. wooden pads and cross bracing are needed to ensure that the mould doesn't distort due to heat when being used. If your mould is thin, it's possible that the heat reaction can draw the mould into a slightly different shape when curing.
The advantage you also get is that your mouldings will be easier to extract from a rigid structure rather than a flexible one.

oh so that's the difference btw horn and waveguide! could never work it out from googling!
But what is it when the plug's added in? Cos then surely it has some compression and an annular throat?
tony: cheers for the tip mate, i'll put it in practice when i reach that stage

When the plug is added in, it is a horn, you are right.

Just remember that any compression driver horn without any added compression (just a clean circular hole) is referred to as a waveguide in practice, even though the compression driver....has compression inherent in it.

Does anyone know an equivalent to the Audax PR170?

Edited by: Deadbeat

Ok ive made a mould for the 6" section i just need some plots and adjust as needed.

That is some skill you have there, sir.

ARTA, soundcard and a mic will do you fine!

This reminds me, I REALLY have to get around to uploading my hornresp model. Expect it in the very short future, along with FSP-ARRAY plots.

lookin fancy, you glassing those in the nearture thenonce youvefinished augmenting the design? Edited by: sKs01