Silly question about pubblishing plans...

Truly I don't like fiberglass, not cheap, not easy to use, dangerous, not so ecologic.
My first thinking was route a phase plug then put in tube 20 cm diameter, thuderidge style but dispersion is not so wide to me... (glad to go wrong in this case )
After I think about a simple squared waveguide and fill it with a round phase plug, main issue are resonance around the baffle, because of the square throat.... any suggestion?

Cost seems to be part of the issue. If you can't or don't want to pay out for prototyping or development, Then don't do anything. Looking for short cuts or a cheap way, isn't the way forward. In the overall scheme of things Neither ply or fibre glass is expensive, especially considering the small amount you would use.
I have just spent a while doing a new upper bass cab to go on top of the new Scoop. It's in ply and weighs to much for a good sound. The problem is, I wanted it to be amazing. Anyway, it's back to the drawing board. The point I make here is that if I thought the sound was average, and I had made it out of MDF or Chipboard, I may be blaming the material, and still wondering whether it would be any better in ply. However, I wasn't happy with the ply box. End of story.
Fibre glass is wonderful stuff, I've been doing horns since 1975. It hasn't done me any harm, although I do tend to ramble.
The fumes will do you less harm than dust from MDF or the resin glue that holds ply together. Be brave, dive in with both feet.

Tony- How would you go about making a prototype fibre glass horn? Would you make the horn from ply first to test it, then make a mould from this, or would you make a negative out of ply then test the first moulding from this? I'm considering making some grp hf horns soon, but as I only intend to make 4 or 6 pieces I'm not sure how to go about this, or whether I should just stick to ply.

Also, how did the box you made weigh too much for a good sound? Surely the heavier the box the stiffer and less resonant, therefore better?

Bitzo- what stage are you at with your plans? Do you have any drawings you could post for interest rather than as finished plans?

Tony your advices are always appreciated I learn everytime but you're in the professional way. To me this is just an expensive hobby, a speaker box that sound bad or good, doesn't matter if I can't use it, will be a waste of wood, energy, time and money...how can I say... before dive in I have to find a pool, but it doesn't make sense if I can't go to the sea because of my job.

Kieran, tube mid plan is quite ready, I posted a rough sketch many months ago in the mid section.

Kieran, I always make a ply horn first. I start with four straight sides which have the dispersion angles for e.g. 60 hori. 40 vert. I then start to fill in and form a shape. The shape I would do now would be based on past experience. The first constant directivity horn I made was done this way but it was tested after each layer of filler was added. I mounted a driver on the back, and with a spectrum analyzer and graphic eq. I produced a straight line on axis. The horn was on a turntable I had made, which was marked up with the appropriate angles. The aim of the process was to get a continuous flat line as the horn was turned on axis. This was achieved with a minus 3db point at the edge of the dispersion. I still use those horns today. The 2" horn is used in the MX600. It took me two days out in the open air with a tub of filler to produce two horns. These main frames were then cleaned up suitable to mould.

Bitzo, there's not much else I can say. I only try to tell people things based on my own experience. I think you have to decide whether to settle for second best, or try to build the cab that will beat every other cab out there. If you only want a cab to do the occasional Disco, then of course, not much of what I say really matters. But, if you are interested in trying to make something worthwhile, then you must take your time, spend the money build the box of your dreams, or at least try to.
In my time before I stopped, I had sold just under £35,000,000 worth of product. I started with £50 I borrowed and worked in my garage, but my mind was made up. I was going to build the best cabs in the world. Whether I achieved that is neither here or there. It's the thought that counts.

Thanks for the advice Tony, that sounds pretty much how I was planning to do it. I have no experience in designing or making hf horns, but I have plenty of ply, filler, drivers and time. A few people have asked me why I don't just buy some horns, but the process is as important as the end result for me, and nobody seems to sell horns that will do the job I need them to.

Kieran, you will be surprised at how much you can learn by doing this yourself. By the time I had done few horns in the early days, I had learnt how to accentuate certain frequencies with shape. Enjoy.