Vented pole piece and phase plugs

[Stanislav]

Hi everyone,

I read a lot of threads and posts, but could not find an answer to my dilemma, hence the new thread.

I just removed the dust caps of 4 x Vifa p11wg midwoofers and installed some handmade phase plugs, using Planet10's approach - wood screws to hold it to the pole piece. The point is the pole piece is vented, there is a small, maybe 6mm hole to the back of the driver.

With the dust cap gone should I plug the pole piece vent with maybe foam or leave it as it is?

Also the VC diameter is 25mm and the plugs that I made from wooden dowels are 25mm too, is this gonna be a problem because of the tight clearance between VC former and the plug and should I use a slightly smaller diameter plug?

Thanks for your input.

Stan

[hunter audio]

hi

closing the vent will result in the voice coil heating when the driver is being loaded to its limits , with a heating coil ull have a whole lot of distortion and other problems

[Stanislav]

Thanks for the reply Hunter, but drilling holes next to the VC former does not appeal to me very much.

I was thinking maybe the gap between the VC and the phase plug would provide enough ventilation, considering that the area of that gap would be greater than the area of a 6mm hole, but I might be wrong.

Anyone with an idea on this?

Cheers

Stan

[planet10]

With the phase plugs installed you can get the same cooling effect from the gap between the plug and the coil.

The plug should cover the vent, but you can stuff them if you want.

Let us know of improvements due to reduction of resonances in VC and vent.

There needs to be sufficient clearance between plug and boce coil for it to move freely. 0.5 mm gap is a good minimum

dave

[Stanislav]

Thanks Dave,

This is very encouraging, I will try 23-24mm corks instead of the wooden dowels, it should provide the 0.5mm gap on each side, and will also block the vent with some foam.

Will report back re. listening tests.

Stan

[Loren42]

Originally Posted by hunter audio

hi

closing the vent will result in the voice coil heating when the driver is being loaded to its limits , with a heating coil ull have a whole lot of distortion and other problems

If you are drilling holes into the steel of the pole assembly or magnet assembly you will create an nightmare of steel shards and debris inside the voice coil!

[hunter audio]

Sorry , I thought you had de -magnetized the motor structure and opened up the top and pole plate , if you have not you can try the thingy in the next drawing - suranjan

[Loren42]

Originally Posted by hunter audio

Sorry , I thought you had de -magnetized the motor structure and opened up the top and pole plate , if you have not you can try the thingy in the next drawing - suranjan

No apologies required.

I just saw an opportunity for a small disaster.

However, I have to wonder about another thing. If you put a steel screw at the base of the plug, that would distort the field geometry of the magnet structure somewhat, would it not?

[hunter audio]

hi please check the attachment

[hunter audio]

attachment