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-   -   49 cent drivers and Damar (http://www.diyaudio.com/forums/multi-way/42062-49-cent-drivers-damar.html)

Sherman 5th October 2004 05:53 PM

49 cent drivers and Damar
 
I built a pair of very small (.11 cuft) two way speakers using the PE 269-570 drivers and the $1.95 Dayton tweeters. I used only a 1uF cap for a highpass to the tweeters (should be around 10K Hz IIRC). Possibly the lowest cost two-way system ever!

I mounted the drivers from the inside. I used a rounding over bit on my router to ease the corners and they ended up looking OK. My first listening sessions using a tube amp were pretty positive but the "bass" (hey you can only get so low with 4" drivers!) seemed a tad muddy, not like my multiple driver systems. Also there seemed to be a noticeable peak in the upper midrange.

I thought they might be OK speakers for my woodshop or something but not for HT. Then when I was at an art supply store I saw a bottle of Damar and remembered some people had positive comments about it.

I coated one driver with the stuff and let it dry overnight. I then listened again. There was a huge and positive difference to my ears with the coated speaker.

I brought in my son and asked him to listen, both speakers hidden behind a grill cover for a larger speaker so he couldn't see which was coated. I set the amp for mono output and switched between the coated and uncoated speaker. Every time with every type of music he said the coated speaker was dramatically better.

Repeat experiment with wife as listener. She is a much less critical listener than my son. Same results.

So my conclusion on this one type of driver in this one type of enclosure is that coating the cones makes a noticeable positive difference.

I'm thinking of coating the cones on one of my larger systems made with these same drivers. If it screws them up, hey I can replace all six drivers for under $3 US!

cancerkazoo 5th October 2004 09:48 PM

What $1.95 tweeter are you talking about? I searched under "dayton tweeter" on PE and didn't see any that cheap.

Steve

Sherman 6th October 2004 03:16 AM

Oops
 
Quote:

Originally posted by cancerkazoo
What $1.95 tweeter are you talking about? I searched under "dayton tweeter" on PE and didn't see any that cheap.

Steve


Steve,
Sorry about that. You are right, I was looking for drivers to repair a set of large 3 ways and apparently have Dayton on the brain.

The $1.95 tweeter is a Goldwood. (270-169) The highest frequency is only about 17K but what is there is pretty clean (and after years of listening to my music much too loud I probably can't hear any over 17K anyway ;) ).

rcavictim 6th October 2004 06:18 AM

Sherman,

How many coats of Damar did you put on the 4" PR Pioneer? Did you do both front and back of the cone? Please let us know the results when you do all of them in your array.

I am about to coat the 10, 6" drivers in my arrays but am still trying different coatings on separate identical drivers. I'm in the process of experimenting with shellac, Weldbond (like white wood glue that dries clear and flexible) and an artist's glazing similar to mod-podge.

Sherman 6th October 2004 06:25 PM

Quote:

Originally posted by rcavictim
Sherman,

How many coats of Damar did you put on the 4" PR Pioneer? Did you do both front and back of the cone? Please let us know the results when you do all of them in your array...


I used one coat on the front and one on the back. I wonder if doing the back is necessary though. When I applied the Damar to another set of drivers I could see that it was soaking through to the back.

The stuff I have is called Damar Varnish and is made by Windsor-Newton. It is very thin, thinner than mod podge, and so it soaks in to the paper cones completely. In fact after one coat the cones do not have any gloss to them. A second coat adds a little gloss.

I'm coating my array drivers this afternoon so I should be able to report back in a day or so.

cytokine 6th October 2004 07:34 PM

Quote:

Originally posted by Sherman



I used one coat on the front and one on the back. I wonder if doing the back is necessary though. When I applied the Damar to another set of drivers I could see that it was soaking through to the back.

The stuff I have is called Damar Varnish and is made by Windsor-Newton. It is very thin, thinner than mod podge, and so it soaks in to the paper cones completely. In fact after one coat the cones do not have any gloss to them. A second coat adds a little gloss.

I'm coating my array drivers this afternoon so I should be able to report back in a day or so.

Please do report back when you have your results. I'm currently doing the same thing while building the baffles for my lines. I'm considering Windsor and Newton varnish as well as thinned rubber cement.

In my listening tests I wasn't sure I was able to tell the difference between untreated and one coat of varnish. I could definitely tell with two coats of rubber cement though. Too much rubber cement takes off the peak at the top end but they lost a lot of sensitivity.

rcavictim 6th October 2004 08:24 PM

Is this Damar varnish an actual real oil based varnish that thins with terpentine, paint thinner, etc?, or is it one of the newfangled water compatible coatings that go on white and dry clear?

I found that with the water based stuff, adding water to thin the product made the paper fibers in the cone get sloppy during the pricess and swell. Not so swell I think. This is an argument against trying to thin the water based glazes, but those are mostly so thick they do not really penetrate the paper cone.

I can see rubber cement killing the highs. I doubt whether they'll bounce back. You aren't always supposed to take the expression describing proof of performance, "where the rubber meets the road" quite so literally. I can see rubber absorbing a lot of HF energy.

johninCR 6th October 2004 09:08 PM

One thing to remember with any of these cone treatments is to allow them to dry fully before listening to them. If you play them too soon you almost guarantee yourself a worse sounding driver afterward. Been there, done that, so learn from my mistake.

RCA,
Dammar is a natural varnish used to protect paintings and is definitely not water based.

ralph-bway 6th October 2004 11:27 PM

I bought about 50 of those 4" drivers and used 13 per side in a line array. I also used 4 of the Onkyo 3/4" tweeters per side at ear height, so I suppose it's a MTM/Line Array hybrid. I coated the fronts of the 4" drivers with "Tacky Glue" from a local crafts store. It seemed to significantly tame the 7K spike that those little ******s have.

My intention was to build these as a practice project and give them away to a deserving friend or family member. My immediate impression of them was that the mids & hights were crisp and detailed with a feeling of depth to them. However the lower midrange to their bottom was kind of muddy.

All in all I was pleased with the results and think they make an excellent speaker to someone who is far less critical than the average member of this forum (which probably constitutes 98 of the world's population).

Sherman 7th October 2004 04:04 PM

Quote:

Originally posted by rcavictim
Is this Damar varnish an actual real oil based varnish that thins with terpentine, paint thinner, etc?, or is it one of the newfangled water compatible coatings that go on white and dry clear?

....


The stuff I have is a real varnish that is designed to be coated over oil paintings as a protective coating. It is clear and very thin no body to it at all.

It is called "Superfine Dammar Retouching Varnish for Oil Colour" by Winsor & Newton. The "superfine" in the name leads me to believe there may be an "unsuperfine" version (maybe thicker?).

It soaks in to the paper cones rather than sitting on the surface and seems to dry completely in only a couple hours. I compared cones coated a few days ago with cones coated and allowed to dry for three hours. I touched each cone lightly with my finger and they felt the same. I then lightly brushed each cone with a cotton swab thinking any remaining tackiness would show as cotton fibers sticking to the cones, there were none. Lastly I lightly brushed the cones with single ply toilet tissue as it contains a fair amount of lint. No lint left on the cones. Hardly scientific but good enough for a 49 cent driver! ;)


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