Really don’t know about the resonances
I have modeled a front loading version to aid tinkering - Exactly to your point
We want a large lipped bolt in variable port throat adaptor
I thought about resin filling - you can have infill profiles that will allow it to flow throughout. However, I decided against this: resin is more expensive than PLA, not actually that much stronger, and more expensive. You might as well just do 100% infill if you’re that bothered!
At this point for me I don’t have the skills to preempt any resonance issues so it will be
simply down to looking at measured distortion levels on the finished product then trial and error adding damping then measuring it again. Wrap around grooves filled with damping stuff to bring rocket science to speaker design - Is a crowd pleaser though.
I have just bought myself a pair large rigid Phenolic horns to sonically compare my diy bits with. Fun days ahead.
Yeah that’s pretty much the reasoning. Even on a warm day where it might only be 25c, PLA will begin to soften if its in direct sunlight. And since the throat adapter has to support the weight of a 3.5kg compression driver off the back of it, you really don’t want it to lose rigidity. I suppose if you’re only going to keep it indoors though it could be fine.
40Hz straight will be massive/tall + base gap for sound to emanate + driver chamber on top = more and more tall..
As suggested, other ways are better unless you really, really want straight horn bass have a double height ceiling and LWB transit to transport them, or do like Japanman and have them way out into the garden (weather proofed) terminating the mouths in the listening room.
Then DSP to time / phase align.
Yes, yes, but we want him to build massive straight bass horns, so we can watch..
Tapped horns only going down to 40Hz will be ‘quite’ small. Lots of threads on DIYaudio.
Had been done with 8" and even smaller twin drivers.
It’s that last octave to 20Hz that gets you to the size we have.
If this is for the AERs, you could either do a 15" OB under them and cross maybe 150Hz, which would save the AERs from stress as well, or do tapped horns below about 80-100
Can you go up into the attic and have them venting to your ceiling?
Imaging huge sectioned snail horns curling around a large attic and down.
Could be removed and ceiling restored on moving out.
Why stop at 40Hz? Go the whole way🙂
Trying to max on an largest size horn flare that can be made in one part.
This is a 250mm x 140mm jobby that I found online - 10hrs printing and 300 grams of filament each. I need to sort out the lines at the top as the flares get closer to horiz - I think there is a way to do this
They will need splitting. Which I think means cleaning up and painting to look nice Give me a few days to review the details - Happy to help - I did outsource my first MEH throats - He might a larger printer -I will check this as well