Velo DD18 Driver

[Nimby]

Hi all

I had the pleasure of a brief examination of a loose DD18 driver yesterday. I can only presume that it was a replacement for a customer's damaged one. The immediate impression was of sheer size and quality. But I was surprised to see what looked like an aluminium can fitted over the magnet area. Is this a permenent feature of this driver? Or a protective device for the loose driver? Perhaps to stop it attracting debris en-route to its enclosure? A magnetic screening can? Somewhere to hide the clever sensing electronics?

Most drivers of this size and quality have a ventilated pole piece. I was unable to confirm if the silver can was perforated underneath. One doesn't exactly manhandle a driver of this size, weight and expense without express permission from the owner!

Just curious, as I've never seen anything quite like this before. Anybody here removed the driver from their own DD18 on a long, wet, boring, Saturday afternoon? Can anybody else shed some light on this unusual feature? A quick Google failed to provide an image of this driver. (clothed or unclothed)

Thanks

 

[Ettepet]

Magnetic shielding, as you suggested?

--
edit: just looked it up, far far away on the internet (link): it should be thin steel, not aluminium.

 

[Nimby]

Thanks. The "can" could have been coated or plated steel I suppose.
Or even something more exotic.

Several of these 18" drivers might make quite a decent subwoofer.

 

[Ettepet]

Several of these 18" drivers might make quite a decent subwoofer.

I agree, it would take several of these drivers, or a cabinet design by SVS to make these babies come to live.

 

[Nimby]

My thinking exactly!

 

[skinnyfat]

You think they're suitable for Infinite baffle, maybe 6 or 8?

 

[Nimby]

No point in messing about with just 6, now is there?
6 is a difficult assymetric wiring exercise anyway.
8 is a nice number!
Series-parallel to maintain the separate unit's impedance.
2000 Watts just to on the safe side.
Don't want any compression effects do we?
Goggles? Flying helmet? Clean underwear?

 

[skinnyfat]

2000 watts per driver

 

[skinnyfat]

Or how about an arrangement like this http://home.comcast.net/~klone-audio/page13-12Shiva1.html

 

[Ettepet]

Or how about an arrangement like this http://home.comcast.net/~klone-audio/page13-12Shiva1.html

I hope they can play (a lot) louder than the table they provided, my 2 PB12-Ultra's beat the cr*p out of that..

 

[Deleted member 49750]

I hope they can play (a lot) louder than the table they provided, my 2 PB12-Ultra's beat the cr*p out of that..

Here are some preliminary measurements. These were taken to determine the frequency response, not to determine output levels.

 

[Ettepet]

If you read my previous remark you'll notice that I refer to just this statement.

Somehow I doubt it plays a lot louder with the smallish opening.

 

[Nimby]

Steady lad. People are in the habit of selling their pairs of DD18s or stacked SVS Ultras once they hear real bass from a True Infinite Baffle.

 

[Ettepet]

Steady lad. People are in the habit of selling their pairs of DD18s or stacked SVS Ultras once they hear real bass from a True Infinite Baffle.

Oh, I'm going to be infinitely baffled one day, but I would use a bigger opening for that many drivers. Or put the drivers in plain view, as it is quite impressive to watch all that power at work.

 

[Nimby]

Your point is valid. The exit area for this particular manifold is undersized for so many drivers. The owner has admitted as much. There are also phase issues with the length of this manifold. The sound from the bottom drivers is delayed relative to those nearest the top, at the manifold's exit point. The installation suffered from a serious lack of space under the floor. A larger grill in the floor was not considered desirable.

Exposing the drivers in an array does offer sound quality improvements. But vibrations cannot then be mechanically reduced by using opposing drivers like you can in a manifold. Arrays of the necessarily-large drivers also take up a lot of room on any wall. Hidden manifolds are widely used for their other advantages. Like being almost completely invisible from the room while still providing bass to die for. The simplest installations are probably in heavy duty doors. But success is in the detail.

The "Cult of the Infinitely Baffled" website has an axcellent FAQ and Guide. With many illustrated examples for those unsure what we are talking about. Don't ask generalised questions on their forum or you will be abruptly referred to the FAQ. There is a very low tolerance for those unable to quote the FAQ word for word! So be warned!

http://ibsubwoofers.proboards51.com/index.cgi?