166es-r enclosure and a baffle

[kazoo]

Hey everyone,
Well its been probably a year since I built the recommended horn for the 166es-r and they sound great. But since I can't leave anything alone I was thinking of making a front baffle for the horns the same as Cain and Cain speakers. Something in the diameter range of 14 to 15 inches so it would go up to the corners for looks. Before I do this just wondering if you guys would think it would be beneficial for the horn to do this. Im still not 100% sure what the baffle does(still learning) for a freqency range. Just wanted to ask the experts' opinions.
Thanks,

John

[Scottmoose]

Well, it does something to the looks.

It'll shift the baffle-step point downward for the driver's radiation, and also, if you put a constantly decreasing radii on it, possibly help with wave-launch. Frankly it's tricky to tell theoretically, as FR units beam considerably high up, which, so the theory goes, should considerably lessent their effect in this respect. However, they do appear to make a difference sonically, whatever the reason. Additional benefits would probably be to slightly mass-load the driver frame, and space it out a little from the chamber, so you may get a reduction in reflections back through the cone, or a lessening anyway. What might be worth doing is seing if you can get the local metal-foundry / workers to make you up a set of brass rings, a la the ESigma series rings, to mount the driver to. Mass-loading of drivers taken to extremes. Works though.

[kazoo]

Well I will try to make this thing and I will report back on the sound change. I just need to find someone that can turn them for me.

I did think about having a brass ring made for the drivers. I found a freind of a freind that had a CNC in his house and he was going to make them for me. Until I priced brass. A 8"x8" piece of .5" thick brass was going to run about $160 dollars and I needed two. So that idea got dropped.
Does it have to be brass? What if I used lead. Make a form, melt some lead and make a ring. That might be the next project down the line.

John

[chrisb]

Unless you're pretty handy in the woodshop (and have a larger than normal lathe), or access to free time on a CNC router, a set of TC style and quality "supra-baffles" should easily cost at least as much as the brass rings.

The best that I've been able to achieve has been with a large profile "thumb-nail" router bit (itself an over $120 piece).

In the commercial woodworking trade the credo is "curves cost money"

[chrisb]

Originally posted by kazoo
Well I will try to make this thing and I will report back on the sound change. I just need to find someone that can turn them for me.

I did think about having a brass ring made for the drivers. I found a freind of a freind that had a CNC in his house and he was going to make them for me. Until I priced brass. A 8"x8" piece of .5" thick brass was going to run about $160 dollars and I needed two. So that idea got dropped.
Does it have to be brass? What if I used lead. Make a form, melt some lead and make a ring. That might be the next project down the line.

John

For a variety of reasons, lead would not be a good idea. Fostex engineers are not the only folks in the speaker business that have used either brass or bronze for some of their more exotic products.

yup it costs more in raw materials and processing time than stamped steel or cast Aluminium or glass reinforced plastics.

[Scottmoose]

Best bet is to make some bronze IMO. It's not difficult, or even particularly expensive, and much nicer to work with than brass. Get down the local scrappies and buy up a goodly quantity of old copper wire, and some tin. I use a ratio of approximatly 12:1 copper / tin for my sword-blades, but for this application, 9:1 would be perfectly sufficient. The interaction with the driver's motor will be pretty similar to what you'd expect from brass, and I suspect more benign than steel etc too.

[G.Kennedy]

What about pouring the baffle out of some kind of resin. Using a big salad bowl with a 8" flat bottom (for a 6 1/2" driver).

A big 1/2 sphere with a hole in the center for the driver.

????

[planet10]

Originally posted by G.Kennedy
What about pouring the baffle out of some kind of resin. Using a big salad bowl with a 8" flat bottom (for a 6 1/2" driver).

Why not just use rge salad bowl?

http://www.ikea.com/webapp/wcs/store...103&langId=-15

ve nice if they made one in wood as big a the large metal one...



dave

[planet10]

Originally posted by Scottmoose
Best bet is to make some bronze IMO. It's not difficult, or even particularly expensive, and much nicer to work with than brass. Get down the local scrappies and buy up a goodly quantity of old copper wire, and some tin. I use a ratio of approximatly 12:1 copper / tin for my sword-blades, but for this application, 9:1 would be perfectly sufficient. The interaction with the driver's motor will be pretty similar to what you'd expect from brass, and I suspect more benign than steel etc too.

hmmm... i'm always selling copper* to the scrapies... where does one salvage tin?

* yokes on CRT moitors is a good source -- and anything less than a 17 these days -- working or not -- is scrap.

And how hot a fire do you need?

dave

[Scottmoose]

Sounds like a good source to me for smaller apps. Using wire was a tip I learned when I first started out & very useful it is too. One thing you have to be careful of -make sure there are no spiders etc attached. As well as being very unfortunate for the spider, if you add it to already molten material, it can explode all over the shop. Bad. So, heat it briefly with a blow-torch before adding to the furnace. Saves grief.

The copper is melted first, and then the tin is added to it. Copper has the higher melting point of ~1100 degrees C (1083 to be exact, but you'll want a furnace that can go higher so you have some leeway). Tin melts at 232 degrees C and effectively is dropped into the mix. You'll see it swirl rapidly, and diamond-white points of light form (very attractive) as it completely melts (which it'll do very rapidly).

Tin is harder to get hold of at the local scrap merchants for me at least, as it's more of a specialist thing. Cans aren't much cop, though if you have a lot of them, and you know they're of decent quality, they can be worth trying. Problem is many have shifted to aluminium these days (shudder). My local merchants sometimes have some in, but it's getting harder to find, so I tend to buy a bulk quantity of small ingots from places like this: http://www.advent-rm.com/items.asp?c...enumber=SN9007 There are others too. A kilogram goes a very long way, and I use a 12% mix. Gets me a good dozen full-sized blades, probably more, depending on what I'm up to. The price fluctuates -you can sometimes get it cheaper. Beware some with a high lead content -avoid anything over ~1%. Not good for the health, and it's not much cop for good quality bronze either IMO.

I'm no expert though -I do this in a fairly unscientific / art way rather than a science, because of my particular interest in the bronze age.