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High Fidelity Speaker Design
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Ash View Drop Down
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Points: 4360 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2016 at 10:18pm





Some front baffle shapes/proportions that I could try with either two driver pairings or four driver pairings. Could try 3mm plywood or 6mm plywood as a start or MDF as suggested by Andrew. The larger designs may overwhelm my small listening room; will have to keep the volume down during testing. When I tried a pair of 12PW on cardboard open baffles, the low bass extension was pretty amazing; it went right down low even at modest playback volume. It didn't struggle to go down. Two 12PW per channel though may help to ensure plenty of air is moved to give a more audible (powerful) really low bass reproduction. Must surely go down past 50Hz with ease.

The great thing about DIY speakers though is I can build baffles that best suit the listening room whilst conserving the same drivers for all designs/rooms.
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Graham Slee View Drop Down
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Points: 16314 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2016 at 10:33pm
No.3 is a column array which is very directional and sound pressure loss is half (-3dB/doubling of distance) of the others you show. Just thought you'd like to know that.
That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps
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Ash View Drop Down
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Points: 4360 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2016 at 10:47pm
Yes please Graham, thanks. Just thinking through some ideas before I get someone to cut me some timber.

I'd like to have more radiating surface yet I'd like to use few drivers so I'm going to have to decide on the best compromise. I think number 4 is the way to go; that way I can hear whether the additional speaker pair per channel gives any advantages/disadvantages.


Edited by Ash - 06 Jan 2016 at 10:50pm
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JamesD View Drop Down
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Points: 246 		Post Options Post Options   Thanks (0) Thanks(0)   Quote JamesD Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jan 2016 at 7:26am
Distance between drivers is also important (or so I've told), i.e. you can't just put them close together to save space or for aesthetics. Something to do with wavelength at the crossover frequency? I haven't got my loudspeaker books to hand at the moment.
Aren't ears brilliant
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Ash View Drop Down
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Points: 4360 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jan 2016 at 11:08am
Yes, I have thought about this too. I think the ideal placement also depends on diaphragm profile which determines the dispersion pattern. Both of these drivers have shallow profiles to allow very wide dispersion and I read an online comment from Mark Fenlon himself stating that for this particular pairing: "the closer the better". I'm trying to visualize what the "two slit" diffraction pattern would look like. There is an equation with wavelength, slit separation, screen fringe width and perpendicular distance to screen "observer". The screen has maxima and minima pattern etc. Aptly named Young's Slits equation. This is for light and electromagnetic waves but a lot of the principles would be the same for sound pressure waves.

Edited by Ash - 07 Jan 2016 at 11:27am
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Drewan77 View Drop Down
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Points: 1544 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Drewan77 Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jan 2016 at 11:36am
What I originally prototyped was a fairly large baffle with hinged tapering (towards the top) wings which could fold at any angle from flat to 90 degrees.

The front baffle had a large rectangular cutout in the centre and then I made various configurations of driver holes in other flat panels of the same MDF thickness that fitted flush into this. The configuration I finally settled on was based on measurements and careful listening.


Edited by Drewan77 - 07 Jan 2016 at 11:37am
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Points: 16314 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jan 2016 at 5:15pm
Interesting stuff. Perhaps contributors to this topic could illustrate with sketches?? (Ash, your's above and Andrews photos noted)


Edited by Graham Slee - 07 Jan 2016 at 5:16pm
That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps
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