Dust Cap Replacement?

[dc270]

I just got 4,6.5" paper cone mid woofers. All the dust caps are crunched in so I thought about replacing them.

What they have now are 2" paper types- what I thought about replacing them with are larger 3.5" thin paper types (like the ones JBL have).

Do/ can dust caps drasticly alter the sonics of a speaker (like this)- within reason of course. (except the Smaller Advent Spit Wad dust cap thing) The replacement dust caps weight is very minimal, and they do cover all but about 1" of the actual cone" They look cool- but I do not want to make the sonics worse. When I A/B them I can't tell any significant differance between an old beat up 2" cap and the newer 3.5" cap.

Just was wonder what experience anybody may have had in this area. I did hear a guy convert a 3" cone speaker to a dome speaker with a 3" dust cap- it actually have better midrange definition- but did lose a small bit of effientcy....
Thank for your/ experience input here!
DC

 

[TerryO]

I just got 4,6.5" paper cone mid woofers. All the dust caps are crunched in so I thought about replacing them.

What they have now are 2" paper types- what I thought about replacing them with are larger 3.5" thin paper types (like the ones JBL have).

Do/ can dust caps drasticly alter the sonics of a speaker (like this)- within reason of course. (except the Smaller Advent Spit Wad dust cap thing) The replacement dust caps weight is very minimal, and they do cover all but about 1" of the actual cone" They look cool- but I do not want to make the sonics worse. When I A/B them I can't tell any significant differance between an old beat up 2" cap and the newer 3.5" cap.

Just was wonder what experience anybody may have had in this area. I did hear a guy convert a 3" cone speaker to a dome speaker with a 3" dust cap- it actually have better midrange definition- but did lose a small bit of effientcy....
Thank for your/ experience input here!
DC

On some "fullrange" drivers the dustcap is removed and a phase plug is installed in it's place. I did that with my Radio Shack 40-1197 drivers (among other things) and it was quite an improvement. Phase plugs can really improve the performance on some, but not all drivers.

Have you tried the vacuum cleaner fix on those dust caps? It may pop them out and if you're lucky it won't be very noticable. All my drivers are very special to me, so I never do anything that could cause them to sound worse.

If OTOH, you are driven to improve the appearence of the drivers in question, and are determined to remove those dustcaps, at least give the phase plug idea a try while the dust caps are off. Just use a socket from your tool bag that's just a bit smaller than the hole and give it a try. It will give you an approximate idea if any improvement will result. I'm sure that I don't have to remind you to use a "clean" socket.

Warning: Removing a steel socket from the pole piece can take a bit of doing so be careful when pulling it out, so as to prevent damage to the cone.

Best Regards,
TerryO

 

[Nat]

First: not sure what was meant by using a socket on the pole piece, but if you remove the pole piece, you have drastically changed the magnetic field -- not a good thing. And yes, it will dramatically lower the efficiency, because it is destroying the intended magnetic field.
Normal pole plugs are a nonmagnetic cone or pointy thing, or bulbous thing, that blocks sound waves from one side of the cone from cancelling sound waves from the other. That's a good thing, but the shape needs to be calculated to fit the driver's response.

 

[TerryO]

First: not sure what was meant by using a socket on the pole piece, but if you remove the pole piece, you have drastically changed the magnetic field -- not a good thing. And yes, it will dramatically lower the efficiency, because it is destroying the intended magnetic field.
Normal pole plugs are a nonmagnetic cone or pointy thing, or bulbous thing, that blocks sound waves from one side of the cone from cancelling sound waves from the other. That's a good thing, but the shape needs to be calculated to fit the driver's response.

Nat,
You remove the dust cap, the pole piece itself is an intrinsic part of the driver and is very hard to remove without destroying the driver. They are not a plug, and they are magnetic, unless your drivers are entirely different from all the ones that are normally seen. Now, if you're speaking about field coil drivers, then yes, when the electricity to the field coil is unplugged, there would be no magnetic field at all!

Best Regards,
TerryO

 

[Nat]

Well that was my point -- but I was making it because I misunderstood what you were suggesting.
When you start talking about sockets, I think its not surprising that people think about using them to loosen something -- now that I read your post for a third time, it was clear to me that you meant to keep the socket in place with magnetic force simply to act as an extension to the pole piece, one that would block waves from the apex of the cone from cancelling. This might be well worth trying, but I believe the socket will lower the intensity of the magnetic field and so may change the sound of the driver. I would think a wood dowel held on by putty would be more neutral.
If the dustcap is solid, a decrease in efficiency is likely because of loss of mid frequency energy off the cap, but the dowel might be less inefficient than the socket.

 

[ryuuoh]

A larger dustcap on a small speaker like a 6.5 could change the sound. Try one with some non permanent adhesive and see how it sounds.