Yes, but with an XO at a low enuff frequency that all the drivers fit within a quarter-wave distance so with the rifgt XO the drivers are essentially coincident, like a coax but without the need for time delay on the tweeter to get the time response right.
ie the point in a point source is essentially a quarter wavelength in size (at teh frequency being reprodiuced). As frequencies go down, the size of the
“point” grows in size.
What is the centre-to-centre? And to keep the transition smooth the drivers need to be voiced similarly. As well as XO — should be time coherent althou at these frequencies thigns are more flexible.
How loud do you have to play? I pay next to zero attention top power ratings since they have little meaning. First thing is ytou will need a larger FR to play really loud.
dave
So, the most prominent characteristic of a true point source is that it emits a totally even spherical field in both level and phase vs frequency. Is this what the OP is seeking? Or is it more a time aligned source with the involved emitters placed in a concentric arrangement for an increased (more beam rather then less) directivity?
//
//
An actual spherical radiator is very difficult. Lots of attempts, all flawed in some way.
A source that radiates like a point over a limited section of the sphere is i beleive what we are talking about.
I imagine an ideal point source as what we would hear (in 3D) if a vibrating 4D sphere was interacting with the 3D part of the universe we can perceive.
Hopefully that makes sense.
A perfect line array would be a 4D circular cylinder
dave
A source that radiates like a point over a limited section of the sphere is i beleive what we are talking about.
I imagine an ideal point source as what we would hear (in 3D) if a vibrating 4D sphere was interacting with the 3D part of the universe we can perceive.
Hopefully that makes sense.
A perfect line array would be a 4D circular cylinder
dave
There use to be early on, but as the net became more mainstream, much of the various colleges, gov't., etc., related businesses went away.
All I have of any use is some old Altec data.
Currently, the xover is 350hz active, no idea about slopes as not in the amp manual. Replacement amps and DSP on hand once a good driver is located
60cm from woofer centre to FR
Same as in the previous high power coax search thread, Currently using 3 FR units per side for SPL but wish for the imaging from only a single source. This is for the same venue as in the old thread
I can't help but think of it as a two-way. Looks like an old ghetto blaster that I had that used a small cone driver in the tweeter position. Is there now a CD available that can be sweet with shrill and reaching loud female voices? That's my only reason for my current bias towards FR units in HF position over tweeters in coax
Man, the biggest improvement would be less shifting of voice and instrument notes and decays and things. For the moment, time alignment is secondary, as can be done through DSP. Coincident via concentric seems to be what I am looking for. Listening area of two 3m x 6m with large glass doors in the middle. Need to cover both sides. Currently, have one pair of FR in one room and two in the other. Better would be something like a DML pair each side of the door presenting the same image in either room, or one higher power FR or coax on the front and back baffle in a common cab and firing into each room from the doors. There is an older thread seeking higher power FR and coax, but this thread is about all the methods as well as development of a dream coax for DIY
A double bass and high-hat duet can sound very off in the current setup
Thank you for that, some is making sense and hopefully some I can hear and measure to recognise
I'll set up a motor and basket structure for a woofer section that can accommodate test cone iterations and various HF units for testing. The woofer section seems reasonable to DIY due to the larger scale of sizes. Target 40-400hz bandwidth. How would something like a 6" MA FR go in the centre position? If this driver was used with a passive 300hz xover with a 12" woofer, what kind of system power can the combined loudspeaker handle?
Proposed VC
Guys, first time attempting something like this. Any recommendations to VC gaps and cylindrical mag sizes? A comfortable 100wrms ability and 12" nominal cone diameter. Max work area is 400mm x 400mm x 400mm on a Creality CR-6 Max and 300mm x 180mm x 40mm laser and CNC. So basket parts can be made from a combination and alloy parts in heat sensitive areas are possible. Aim is to create a very large vent area that can house part of the HF structure
Guys, first time attempting something like this. Any recommendations to VC gaps and cylindrical mag sizes? A comfortable 100wrms ability and 12" nominal cone diameter. Max work area is 400mm x 400mm x 400mm on a Creality CR-6 Max and 300mm x 180mm x 40mm laser and CNC. So basket parts can be made from a combination and alloy parts in heat sensitive areas are possible. Aim is to create a very large vent area that can house part of the HF structure
That centre-to-centre means that the XO needs to be about 150 Hz or less to meet the quarterwave requirement.
What 2.75” FR?
dave
Dave, it's not on the retail market. The motor structure is from the 3" Tang Band FR with the phase plug but in a smaller basket with a smaller cone. I think, a volume item only for Systems developers. I want to move up from these. If something like the Mark Audio 6" FR drivers can be way louder then I can try to fit one into a larger DIY woofer
re the DIY driver, is there any reason for the VC to be inside the mag? Can there be an array of flat bar mags round a cylinder and the VC ride over that?
re the DIY driver, is there any reason for the VC to be inside the mag? Can there be an array of flat bar mags round a cylinder and the VC ride over that?
The A10p (5.25”) is better than the A12p (6”) and would be my choice for a system that goes loud.
dave
An ESL 63 isn't a point source, but the sound it radiates from the front approximates the wave front of an imaginary point source some 30 cm behind the loudspeaker. Peter Walker wrote about it in
P. J. Walker, "New developments in electrostatic loudspeakers", Journal of the Audio Engineering Society, vol. 28, nr. 11, November 1980, pages 795...799
There is also a most interesting chapter about them written by Peter J. Baxandall, chapter 3 "Electrostatic loudspeakers" of the Loudspeaker and headphone handbook.