pinkmouse said:Dunno, I think it might look quite cool. Two on the front, two on the back. It's got to be worth a test box, how else are you going to use up all those drivers!
It might look cool yeh! And I agree I need to do test boxes (hopefully will do some of that this weekend!), but there's a small obstacle to overcome if I clamshell mount the woofers into each other - the surround protrudes from the basket! I'd need some kind of spacing ring (can't be making those with my tools/skills very easily).
Couple of thoughts.
If you don't need the screening, it might be worth disecting one driver to see how easily the can and extra magnet come off. That would make the drivers look a bit cleaner/ more attractive.
If you do go for isobarik for the final cabs, then I'll mill up some spacing rings to your dimensions for you in return for a few drivers.
I can't wait to see your results!
If you don't need the screening, it might be worth disecting one driver to see how easily the can and extra magnet come off. That would make the drivers look a bit cleaner/ more attractive.
If you do go for isobarik for the final cabs, then I'll mill up some spacing rings to your dimensions for you in return for a few drivers.
I can't wait to see your results!
Hi Simon,
the cabinet wall becomes your spacing ring.
Is that wall too thin to be a spacing ring?
Remember that the two speakers in isobaric move in the same direction when powered.
How about a line array? From the little I have read no box sound to interfere with the music and performance down to about Fs.
A sheet of stiffened ply would be MUCH easier to build than a box!
Re. measuring your T/S parameters. I have seen recommended that hanging the speaker away from nearby surfaces gives correct results. Your light speaker could be hung from a centre of room light fitting. Any chance you could repeat your T/S measuring and confirm IF there is a difference?
the cabinet wall becomes your spacing ring.
Is that wall too thin to be a spacing ring?
Remember that the two speakers in isobaric move in the same direction when powered.
How about a line array? From the little I have read no box sound to interfere with the music and performance down to about Fs.
A sheet of stiffened ply would be MUCH easier to build than a box!
Re. measuring your T/S parameters. I have seen recommended that hanging the speaker away from nearby surfaces gives correct results. Your light speaker could be hung from a centre of room light fitting. Any chance you could repeat your T/S measuring and confirm IF there is a difference?
pinkmouse said:Couple of thoughts.
If you don't need the screening, it might be worth disecting one driver to see how easily the can and extra magnet come off. That would make the drivers look a bit cleaner/ more attractive.
If you do go for isobarik for the final cabs, then I'll mill up some spacing rings to your dimensions for you in return for a few drivers.
I can't wait to see your results!
Good morning chaps,
I posted a reply already, but diya went down mid-post and I lost it
Anyway, I think what I said was that should I need spacing rings PM, I will be straight in touch with you, and I very much appreciate the offer.
I don't think I need to lose the shielding part, as it looks ok. Altho my other drivers aren't shielded so it's a bit of a waste, but nice to have. What worries me a little though, is the possible filtering effect of the sound having to go through quite small holes in the driver frame. Care to guess how high I can x-over without this being a problem?
AndrewT said:
Hi Andrew,
Some interesting thoughts here. The cabinet wall could indeed form my spacing ring, but I bet it's harder to implement than it sounds.
A line array (maybe even OB/dipole) would be sweet, but I just don't have the space in my shared house/room.
I may re-measure that driver hanging to see if it measures differently. Perhaps not from the light fitting tho, lol! Maybe I'll just rig some hanging wires up from my trusty £10 workbench.
Thanks for the suggestions thus far.
Nemophyle said:
Hi there!
The reason is simple - in this configuration each driver is a compound driver - that is, two drivers facing each other, with no air leaks inbetween (it is sometimes called a 'clamshell' for obvious reasons. In that diagram, although you can't see them all there are supposed to be EIGHT drivers!
Isobaric loading halves the compliance and therefore the Vas (this determines cabinet size), so to have the response and box size the same you need double the (compound) drivers.
Having 4 pairs like this gives the same frequency response as 2 ordinary drivers in the same box, only now there is 4 times the thermal power handling, and theoretically lower distortion too.
This is because as one half of a pair pushes the other pulls (it's wired out of phase, and hence the name 'push-pull'). This supposedly reduces non linearities caused by the voice coil leaving the magnetic gap, or something like that.
I think I may have explained this all quite badly, sorry if it wasn't clear.
pinkmouse said:Makes sense to me, but then I understand the principle.
As for noise, I have done this kind of thing before, and run up to about 200Hz, but that was with 10" drivers. It is probably worth just fixing one to a bit of sheet material and having a listen with a signal generator.
200hz isn't so bad... and these blatently won't be close in pure quality terms to my current mid/basses so I don't want to make them play too high! Got to make a trade-off between overall headroom/power distribution and the cheap drivers spoiling the gentle music!
After work and the gym and cooking it's always too late to do anything on a week day, but I'm gonna try to get some work on this done on Saturday!
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