Going to try Swingin this weekend – how to get it right first time?

[otto88]

No, not a '70s style four+ some

This weekend I'm making a swinging dipole system a la mige0 Beautiful Swingin' Speaker

I want to swing a fullranger (to be crossed to midbass about 250 Hz).

The driver weighs about 5 – 6 kg(!), is 240 mm across, yet has only 4 bolt holes.
With the bolt holes facing on diagonals facing “North East”, “North West”, SW and SE, I’d think only the 2 lower bolt holes could be used to suspend the driver. So each hanging wire would carry about 3 kg.

So I was likely to put it on a minimal square baffle (18 mm ply) maybe 280 mm across, which could provide 2 or 4 additional points (hooks?) to hook wire up to.

Based on the improvements that cuibono found when he oriented the Violet drivers radially straight at the listening position Violet DSP Evolution - an Open Baffle Project

I could then use 2 of the additional points to control the angle of the baffle (hence the driver), by adjustable wires to the rear.

Hope all that is clear

So to carry either 1.5 or 3 kg per hole for a swinging system; and separately control the angle of the baffle, what sort of wire?
And swinging from above, to allowing front – back movement - hang the wire off hooks?

Any other advice?

Thanks

[otto88]

Just use a strong wire, that is insulated to lower friction? . .

[StigErik]

I've found that its a good idea to have suspension in the vertical direction as well - or else some vibration will transfer through the wire used for suspension. I use rubber straps to provide that. In fact I suspend four 8" woofers with just two rubber straps, total weight is approx 9 kg.

[otto88]

Good idea, looks great ;!
What sort of shop sells rubber straps?

[StigErik]

Look for them in car or truck accessory shops, that's where I found mine. The type I used are in the US called "truck tarp straps". They are quite strong and not too flexible - perfect for some kilograms of speakers.

[twest820]

Stig Erik and Michael both hung using bolts through the mounting holes, though Michael's cable runs also go around the magnet. I hung by supporting the magnet and nothing else; you can almost certainly avoid the hassle of cutting a baffle by using a similar approach with the Supravoxes. It'll depend on exactly how the magnet's built and where the balance point of the driver is, but I'd be surprised if their center of mass is forward of the magnet or if you need more than light trimming tension on lines to the mounting holes once the magnet's supported.

I've had good results with picture wire---can't feel any vibration in the frames; whatever's there is lower level than my pulse. Another option is to put the magnet in some sort of sling. Canvas and old climbing webbing were two possibilities I considered but stranded wire and screw eyes were handier. For fabric I was thinking of having a bit of a jig which would make it easy to adjust the sling's position and then clamp it place; just a couple blocks of wood. I'm unsure why Stig Erik hit problems with the chains he was originally using but, at a naive level, it would seem a series of rigid links would be more prone to rattles and such than a continuously flexible support. One suspicion I have is the links may have been working against each other.

[otto88]

Thanks guys!
I’m goin home via the shops

i'll read up the link soon too

[StigErik]

Any progress?

[otto88]

Thanks for asking Stig

Some, but not yet swinging yet: I'm doing some niceties (eg roundovers and some complexities with the woofer, which is conventional OB with little wings.

The complexity is the way I'm providing the fullranger with a littel platform from which to swing, and a way of being able to adjust its angle up and dowm

I should have taken a couple of pics. Next time I’m at the workshop, if things go well I hope to be able to "bring the baby home"

Then to start on the PC XO ..

[otto88]

I had thought that the main benefit of decoupled mounting (originally by magnet mounting, now probably better on balance by mounting on a “swing”) was in the mid range.
Maybe because my first knowledge of dipoles was Linkwitz, and he decoupled the "mids" (120 - 1400 Hz), when I learnt of swing mounting, I focused on the mids.

And of course bass response is extended is by a baffle and wings, which increase D.

I'm now 80% through building my first OB speaker, with nice marine ply baffles (with large roundovers), wings & base cut. The next step would be to stain, then glue and screw it with the midwoofers (to run up to 350 Hz) in baffles . .

It just occurred to me:

Should I skip the glue, so I can pull it apart, or maybe better complete one ~ but skip the glue, and swing mount the other and compare?

Nb: the midwoofers weigh 11 kg each: 98 dB 15 inchers. I’d need some good strong rubber straps