Tips on drivers

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Hi all,

Once upon a time I read in a diy project how to make a vifa tweeter sound better doing nothing but dismounting and fixing some internal whatsoever, I forgot what and where...:scratch:

Does anyone know any trick to improve a driver? I know that the production line is not perfect and they are not asked to be, so some things can be "fixed" by a diyer

Thanks,
 
--Does anyone know any trick to improve a driver

This isn't the answer you seek, but I don't like to use
exotic drivers that are problematic and need
taming via elaborate crossover design and whatever
black magic is needed to make it sound good.

Just buy drivers that sound good to "you". It's hard
to do unless you audition some with minimal filtering,
but it's the only way to find peace - lol
 
frugal-phile™
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Raka said:
Does anyone know any trick to improve a driver? I know that the production line is not perfect and they are not asked to be, so some things can be "fixed" by a diyer

Almost all drivers can benefit from tweeking -- some inexpensiv drivers cn be made dramatically better.

One has to be careful, or willing to loose a driver or 2, because tweaks can go wrong. Here are some examples:

1) damp the basket or the can over the back of your tweeter-- duct seal works as do many oother things
2) reduce early reflections off the basket (and in the case of your tweeter off the inside vent etc)
3) treat the cone. Damar, puzzlecoat are commonly available, "official" stuff like Lords BL100 are harder to come by
4) remove the dustcap
5) add a phase-plug -- try this on a cheap come tweeter, you might be surprised
6) plug the pole vent (only in conjunction with dust cap removal and will compromise the thermal capabilities)

dave
 
of the 6 dave recomends I have done all but 3, 4 and 6.

treating the cone will change Mms I dont recomend it esp for a tweeter. For a woofer it can be recomended.

for woofers if you remove teh dust cap i find replacing it with Leggs pantyhose boxes (the come in the spake of a phase plug) works. I am hoping to one day draw an aluminum dutcap from 0.35mm aluminum the sort you see in lighting reflectors. (before I am shot yes I know they used to use 0.5mm but now they use a thinner gauge to save weight and money).

i have also replaced the face plate of tweeters with machined aluminum face plates. the plastic face plate of some tweeters are ugh.

i used blu tak for 1.

hope this helps
 
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navin said:
treating the cone will change Mms I dont recomend it esp for a tweeter. For a woofer it can be recomended.

Too much on a FR can kill the highs. Don't discount using it on tweeters, cones especially, just keep in mind the lower the mass the diagram the easier it is to affect the mass.

i have also replaced the face plate of tweeters with machined aluminum face plates. the plastic face plate of some tweeters are ugh.

Good one.

dave
 
so dave if you takeoff the dust cap of a tweeter it will still work.. what about a woofer.. will it still work.. i cant see why it wouldent but why would you..i have a 15" driver that might sound better with teh dust cap off since it soundslike air is getting traped in between and has to escape some where witch makes a loud whissle at high volumes.. expecialy when the sub is moving larg mounts of air so i still plug the hole at the back of teh magnet. it is about 2" hole..


j'
 
What if you make a small hole, like in Audioms?
 

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frugal-phile™
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Peter Daniel said:
What if you make a small hole, like in Audioms?

That is enuff in a lot of cases. Fostex uses the same trick on some of theirs. The dustcapectomy often works best in conjunction with a phase plug which requires removal of the entire cap.

Bose(o).

Be careful and methodical... Remember it isn't very undoable, and don't get anything in the gap -- a drill might not be the best tool. A very sharp razor knife, or the hot tip of a soldering gun are preferrable.

dave
 
i use an exacto knife. i know you guys get it in the US.

dont use a drill you will create dust.

your enviroment must be clean and dust free.

Dave how come you still use cone tweeters? any spec. app?

Last time I saw cone tweeters was when I was repairing a Bose 301. Philips makes some nice ones too so I dont discount the technology just have not seen many around.

A dust cap is required for exactly tht keeping dust out. If one is replacing hte dust cap find an alternate dust cover. One way is to convince you significant other to wear Leggs. :)

Love
navin
 
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navin said:
how come you still use cone tweeters? any spec. app? ... I dont discount the technology

no special ap, but i see a lot of these, and some of the little ones sound quite good and have room for improvement. And most of them cost nothing.

If you look at the Previous Tweeters in The Tweeter of the Week page, you'll see that my favorite is a 50 mm open-back isophon, and the $2 thimble tweeter did a credible job. The more modern domes haven't made it to the tasting yet.

And if you want to go out and buy something new the Jordan JX53 is a seriously good tweeter and i have heard good things about the .Peerless.

dave
 
the Jordans are more than tweeters (as are the Bandors).

the peerless one is nice. I have used a smaller tweeter (less than 2") cone made by Philips. it had a small plastic rear chamber. mounting it was complicated as it did not have a faceplate to screw. one had to build a plate out of wood and clamp the tweeter between the wooden plate (that has a 2" hole in it) and the baffle.

cheers
 
Hi Raka

Could it be that they were talking about removing the Magnaflux out of the gap ?
There are people who consider tweeters without magnetic daming fluid to sound better.
At the moment I don't know if there is any Vifa tweeter model using magnetic fluid at all, but I am sure that there are models with magnetic fluid available from this group of speaker manufacturers (Danish Speaker Technology: Scan-speak, Vifa and Peerless).

Regards

Charles
 
Thank you for your input

Hi all,


It seems there are a lot of things to do, that's good. Planet10, I have some questions: 1) How I damp the basket? Do I have to put some felt in the "legs"? If the tweeter is fitted in a separate enclosure, is redundant to damp the back of the tweeter? 2) Reducing reflections off the basket. How? 3) This point might be out of my capabilities, no suppliers near to help too. 4) Removing the dust cap? Whoaaa, that's new for me, I love this kind of things!! Could you please provide me with some details? What's the point on doing this? 5) What is a phase plug for?:confused: I'm sorry to be so newbie. Any place to look for how to make this?
6) I will try this after all previous points.

Thank you very much for your responses, If doing this I get improved drive units I will you pay some beers with the saved money!!
 
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Re: Thank you for your input

Raka said:
1) How I damp the basket? Do I have to put some felt in the "legs"? If the tweeter is fitted in a separate enclosure, is redundant to damp the back of the tweeter?

I use duct seal (available at HVAC wholesaler if not at home despot). This goes on the outside of the basket and in the crevice between magnet & frame (unless you are doing the "potting the magnet" mod). This kills vibration & resonance. (so yes it is still needed on the tweeter).

2) Reducing reflections off the basket. How?

This is where the felt (or foam comes in). On the inside of the legs to reduce the magnitude of reflections off them from the back of the cone.

5) What is a phase plug for?

It effectively halves the distance across the cone, doubling the frequency of any resonances. Fills the hole left after you take away the dustcap (killing the tin can resonance)


will you pay some beers with the saved money!!

I've collected almost enuff beers to last a lifetime on this forum. I must be allergic to alcohol, half a beer and i'm gone, and a generous helping of single malt is as little as you can get on the bottom of the glass and still get it all wet. Bristol Cream i can actually drink an entire (little) glass of.

dave
 
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