phase plugs for b&w kevlar driver
Hello All,
My first post here....please be gentle. My daughter recently had her way with my b&w lcr600 s3. More specifically she crunched the dust caps on the two kevlar drivers. The dust caps come to a point.... and actually look like phase plugs...though they are not. They aren't pushed in....she actually crunched them on the sides...Also....turns out that my grey dust caps...are actually painted gray...they are clear underneath. I know this because she somehow managed to chip off a fair amount of the paint.
Neways... I found that I can pay 100 bucks per speaker to replace the two kevlar drivers...but thats a bit hard to swallow considering the speakers still appear to work...well enough. But I can't stand to look at them... I like (liked) having the covers off.
More to the point now ..I was wondering if anyone had ever tried putting phase plugs in place of the dust caps on the b&w drivers....or other kevlar drivers. The dust caps appear to be glued. I'm tempted to try to remove them but am hoping someone can offer some words of wisdom before I dive in.
Thanks for any help\info
Hello All,
My first post here....please be gentle. My daughter recently had her way with my b&w lcr600 s3. More specifically she crunched the dust caps on the two kevlar drivers. The dust caps come to a point.... and actually look like phase plugs...though they are not. They aren't pushed in....she actually crunched them on the sides...Also....turns out that my grey dust caps...are actually painted gray...they are clear underneath. I know this because she somehow managed to chip off a fair amount of the paint.
Neways... I found that I can pay 100 bucks per speaker to replace the two kevlar drivers...but thats a bit hard to swallow considering the speakers still appear to work...well enough. But I can't stand to look at them... I like (liked) having the covers off.
More to the point now ..I was wondering if anyone had ever tried putting phase plugs in place of the dust caps on the b&w drivers....or other kevlar drivers. The dust caps appear to be glued. I'm tempted to try to remove them but am hoping someone can offer some words of wisdom before I dive in.
Thanks for any help\info
How do they sound?
Sometimes, these dings don't make a lot of difference in sound. If you're hearing buzzing or missing bands then you're in for some cash.
However, before you give up on them, try reforming them. I've heard of people fixing cones/domes with a number for ways. Blutack-that stuff for sticking pictures on the wall can be used to pull out dings. Scotch tape (sellotape) can also work. You can remove the driver and see if there's a way to apply back pressure by blowing whilst holding the cone still to pop out the dings. Get creative - the worst thing is you'll bugger the driver up - which it is anyways
If all else fails, I'm sure you'll get some good advice for replacements.
good luck!
Then Dave (Planet10) might have an opinion too
Sometimes, these dings don't make a lot of difference in sound. If you're hearing buzzing or missing bands then you're in for some cash.
However, before you give up on them, try reforming them. I've heard of people fixing cones/domes with a number for ways. Blutack-that stuff for sticking pictures on the wall can be used to pull out dings. Scotch tape (sellotape) can also work. You can remove the driver and see if there's a way to apply back pressure by blowing whilst holding the cone still to pop out the dings. Get creative - the worst thing is you'll bugger the driver up - which it is anyways
If all else fails, I'm sure you'll get some good advice for replacements.
good luck!
Then Dave (Planet10) might have an opinion too
Yeah phase plugs might work. Although it might not be a perfect solution. The phase plugs would need to match the geometry of the original dust cap phase plugs.
Keep in mind that having phase plugs rather than dust caps means that the cone is slightly lighter which means that all the speaker parameters will change slightly. For instance, the resonant frequency will be higher, which will make qms and qts slightly higher. These changes have subtle, but predictable effects on the low end frequency response. The effects the modifications will have on the midrange response are less predictable. Closely matching the geometry of the dust caps will help mitigate changing the frequency/polar response too much.
In terms of resale value you might be better off just replacing the drivers. You might also consider selling your crunched drivers in the swapmeet forum to offset your cost. There are people here that have the equipment and expertise to replace the dust caps, or put in some phase plugs, measure the modified drivers, and use those parameters to optimize a speaker around them. Unfortunately in your situation, the chances the phase plugs will improve the speaker are not very good, your really just hoping to not degrade it too much.
my 2 cents
Keep in mind that having phase plugs rather than dust caps means that the cone is slightly lighter which means that all the speaker parameters will change slightly. For instance, the resonant frequency will be higher, which will make qms and qts slightly higher. These changes have subtle, but predictable effects on the low end frequency response. The effects the modifications will have on the midrange response are less predictable. Closely matching the geometry of the dust caps will help mitigate changing the frequency/polar response too much.
In terms of resale value you might be better off just replacing the drivers. You might also consider selling your crunched drivers in the swapmeet forum to offset your cost. There are people here that have the equipment and expertise to replace the dust caps, or put in some phase plugs, measure the modified drivers, and use those parameters to optimize a speaker around them. Unfortunately in your situation, the chances the phase plugs will improve the speaker are not very good, your really just hoping to not degrade it too much.
my 2 cents
Thanks for the help....I was able to get some of the dents out by using tape. I think I'll try removing the drivers to see if I can push the dust caps out somehow from behind.
I haven't noticed any difference in sound quality, though in general I've felt this speaker does not sound as "brilliant" as the towers in the same range...which doesn't make much sense to me. They are supposed to have the same tweeter.
If I am able to get the caps pushed out all the way...any suggestions on what type of paint I might use to repaint over where its been chipped off?
I haven't noticed any difference in sound quality, though in general I've felt this speaker does not sound as "brilliant" as the towers in the same range...which doesn't make much sense to me. They are supposed to have the same tweeter.
If I am able to get the caps pushed out all the way...any suggestions on what type of paint I might use to repaint over where its been chipped off?
Thanks for all the help and suggestions. I tried removing the speakers to see if I could somehow get the caps pushed out from behind...it wasn't possible. I was able to get some of the dent out of one of them with scotch tape.
I've attached a picture, it's not for the faint of heart..this is actually before i was able to get some of it back out.
I've attached a picture, it's not for the faint of heart..this is actually before i was able to get some of it back out.
An externally hosted image should be here but it was not working when we last tested it.
Hoover it.
That's saved speakers lots of times for me when "mates" have been out poking.
This might be a long shot, but could you take them off, get them back to shape, then restick?...... I said it was a long shot.
As I said before - get a hoover, put it over the dustcap, switch it on. DO NOT pull it off. Wait for 5 secs, then switch off the hoover. Then remove the nozzle. Note - must be a reasonably powered hoover.
That's saved speakers lots of times for me when "mates" have been out poking.
This might be a long shot, but could you take them off, get them back to shape, then restick?...... I said it was a long shot.
As I said before - get a hoover, put it over the dustcap, switch it on. DO NOT pull it off. Wait for 5 secs, then switch off the hoover. Then remove the nozzle. Note - must be a reasonably powered hoover.
I think that's just chipped paint, Dave. The vacuum cleaner trick may work. (Then again it may just rip the dustcover with out of the cone )
Painting them is going to be hard to get a good finish. I'd spray paint myself. Make up some cone masks to protect the kevlar cones, carefully tape everything up and s l o w l y build up a layer of paint. You want to barely mist the paint on rotate, alternate and give it time between sweeps. Patience is a virtue!
)Painting them is going to be hard to get a good finish. I'd spray paint myself. Make up some cone masks to protect the kevlar cones, carefully tape everything up and s l o w l y build up a layer of paint. You want to barely mist the paint on rotate, alternate and give it time between sweeps. Patience is a virtue!
The picture may be a little deceving. The dust caps are supposed to be gray, but it turns out they are just painted gray. So where my daugter had her way with them....the paint actually chipped and flaked over. Underneath the paint its just clear plastic...or something similar.
So there aren't actually any pieces broken off...unless you consider the pieces of my heart...that were broken
So there aren't actually any pieces broken off...unless you consider the pieces of my heart...that were broken
Installing phase plugs instead of the creepy plastic is in absolute terms the best way to go.
"Only" downside: they will not sound the same and you probably are going to need readjust the crossover.
Did this myself(willingly !) for my 602 S3s and it fell like a significant improvement (but I have changed the tweeters and, of course, the crossover.
"Only" downside: they will not sound the same and you probably are going to need readjust the crossover.
Did this myself(willingly !) for my 602 S3s and it fell like a significant improvement (but I have changed the tweeters and, of course, the crossover.
I'd second the hoover technique, its got me out of trouble a couple of times. Depending on how pliable the dustcap is, I'd try locally heating the cap with a hot air gun or hair dryer (Be careful!). This makes it a bit more receptive to being turned inside out and will help with creases. You can then paint em to look pretty with acrylic paint. Good luck!
Neat idea.
About the creases - look at the driver on the left. It looks to have been returned to its normal shape, but I can't see any creases...
+1 on the hair dryer then hoover.
It's your choice, but I would advise trying to save them first, as the sound won't match the rest of your system if you decide on phase plugs (I'm no expert, so I could be wrong, but XOs and tweeters were mentioned, so I can only assume the sound will change).
Chris
PS - maybe it would look better without the paint on them... random last minute thought...
About the creases - look at the driver on the left. It looks to have been returned to its normal shape, but I can't see any creases...
+1 on the hair dryer then hoover.
It's your choice, but I would advise trying to save them first, as the sound won't match the rest of your system if you decide on phase plugs (I'm no expert, so I could be wrong, but XOs and tweeters were mentioned, so I can only assume the sound will change).
Chris
PS - maybe it would look better without the paint on them... random last minute thought...
Cut them off and plug in some real phase plugs!
Recently I got some plugs made by a local machine shop - short billet aluminum rod lathed into the shape I want:
This is for my woofers with 3" voice coils. I got 4 of them, so here they are:
The lower/smaller part of the plug is going to 'plug' into the vent on the pole peice.
Fit in nicely:
And 2 of them on the baffle:
I remember reading John's post stated that de-capped woofers sound better, so I cut mine. However the ugly 3" holes are not easy to deal with. Finally I plug those holes.
I don't know how they sound, yet. But even if they sound worse, I won't remove them. Never.
Recently I got some plugs made by a local machine shop - short billet aluminum rod lathed into the shape I want:
This is for my woofers with 3" voice coils. I got 4 of them, so here they are:
The lower/smaller part of the plug is going to 'plug' into the vent on the pole peice.
Fit in nicely:
And 2 of them on the baffle:
I remember reading John's post stated that de-capped woofers sound better, so I cut mine. However the ugly 3" holes are not easy to deal with. Finally I plug those holes.
I don't know how they sound, yet. But even if they sound worse, I won't remove them. Never.
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