Beyond the Ariel

[Pano]

Yes, paper maché is very labor intensive. It's cheap, but it's quite a chore (and messy). Very neutral sound, tho.

[ScottG]

Originally Posted by Truetone

Papier mache is a good idea, but of course the problem is the mould. I give full instructions on my website (Azurahorn.com) but in reality it is more work than you would want to go to. An alternative method is to build up concentric discs of 2 ply cardboard (using he Le Cleac'h spreadsheet) and fill the steps.

The profile is not proprietary - anyone who wants to give it a go can enter the input data into the spread sheet and obtain it.

T=0.707
425 Hz cut off
one side wall angle 4 degrees
Throat 1.4"
Mouth diameter 420mm

Having just returned to the fold after a detour round TD2001s on 340 horns and Lowther PM2A on 204 horns I can say with confidence that the design choices that Lynn took wrt the 425 horn are spot on - hard to describe but you get that immediate feeling of it's just right.

martin

I suspect that if anyone balks at about 600 US for custom horns - then this isn't the project for them, regardless (..at least for the time being). The fact is that everything else is *more* expensive, and I'd bet that the crossover done with correct parts will just add to this - substantially. Trying to "save" 600 or so on a 3+k project almost certainly isn't a good idea.

..of course an enthusiast modeler crafting the horns for the joy of it - that's something different.

[Pano]

I built my crossover for about $125 a side and am very happy with it. The inductors are the major cost.

Building the horns is a big project, beyond the scope of many here. But this is supposed to be DIY, right? I was lucky, I got a great deal on my Altec horns so didn't need to build.

[ScottG]

Originally Posted by Pano

I built my crossover for about $125 a side and am very happy with it. The inductors are the major cost.

Building the horns is a big project, beyond the scope of many here. But this is supposed to be DIY, right? I was lucky, I got a great deal on my Altec horns so didn't need to build.

Yes, but Pano - you're *magic*.

I've a feeling it's like cooking for the rest of us - you can have the ingredients and cooking instructions down to the very last detail and still f....it-up.

[Truetone]

I found a great way to diy inductors is to wind them on 5" or 7" RtoR tape reels. This narrow profile is actually the most efficient (lowest DCR) when you check it on the coil winding calculators. I used paper and oil vintage grey can type caps (keeping pcbs out of land fills). What is the opinion on these?

I guess diy is cheap when you have a shed full of junk, but acquiring the junk pile is big investment :-)

martin

[pengesluk]

Originally Posted by Truetone

I found a great way to diy inductors is to wind them on 5" or 7" RtoR tape reels. This narrow profile is actually the most efficient (lowest DCR) when you check it on the coil winding calculators. I used paper and oil vintage grey can type caps (keeping pcbs out of land fills). What is the opinion on these?

I guess diy is cheap when you have a shed full of junk, but acquiring the junk pile is big investment :-)

martin

Hehe... those are most definiciously words of great wisdom!

[datesx]

Am I right if I think most of the members here are US-located? For us, poor Europeans these prices are almost double so high. If I am not mistaken the formula to get something into the EU is: (price+delivery cost)*VAT(up to 27%) +customs(~6..8% of the price)
As the only delivery method is air cargo to get 2pieces of GPA 416 might cost 350$ or so.
Additionally, it is hard to make business from here with these guys (GPA, RADIAN, etc) - no WEBshop, no EU distributor, they don't like answering emails ...

On the the hand, there are many nice European products so to find more or less correct replacements for the pieces recommended by Lynn should be possible. The only piece what I would buy from US is the CD - Radian 745 (PB/NEO).

So what are the impact factors to use:
288 -> 745 (maybe ND1460A) (only 8Ohm available?)
416 -> 2 pieces of 12NDA520 (only 8Ohm available?)
RAAL -> RAAL (the only piece which is cheaper in EU)

Any better idea (based on personal experience)?

[Pano]

Originally Posted by ScottG

Yes, but Pano - you're *magic*.

Yes, well.... the $125 is simply parts cost from Parts Express, so it's a bit of a cheat.

As Martin says:

Originally Posted by Truetone

I guess diy is cheap when you have a shed full of junk, but acquiring the junk pile is big investment

Very true, and I had parts on hand so that I could experiment with different values. I don't have tons of spare parts, like some guys I know who literally have buckets full (you know who you are).

The big cost is R&D. For that I had a DCX2496 active crossover to experiment with slopes, crossover points, filter orders, phase, etc. I did not include that in the cost - but it's important.

I still think that if someone else designs the crossover you'd not be in for more than $300 for the pair, unless you use boutique parts. I did not. Solen, Erse, Janzten, Mars. I don't know what Lynn has in mind for the LTO, but my (or Mr. Hiraga's) crossover for the A5 should not cost USA builders more than $300 at current prices. I think mine is a 12 or 13 element crossover for 3-way.

Of course for the LTO crossover the price is just a guess, as I have not seen the BOM.

[Keith Taylor]

Originally Posted by Truetone

I used paper and oil vintage grey can type caps (keeping pcbs out of land fills). What is the opinion on these?

martin

I guess any oil filled capacitors need to be identified as containing or not containing PCB's before disposal. In Australia Ducon was a major manufacturer and their products were used in locally made TV and radio transmitters, Beyer/Rola/Plessey tape recorders and many other products.

Coming from the Broadcast industry I learned that any Ducon caps with N or S in the part number contain PCB's.

We used to have standard procedures for dealing with them which involved taking them to a depot and storing them in drums for future disposal. That was originally going to be high temperature incineration, but I believe there is an improved method. The PCB's are sealed in an atmosphere of boiling nitric acid and when removed the resulting compounds are benign in the environment.

Sorry to be off topic, but I will use the dissemination of safety information as the reason.

Keith

[Truetone]

Good info, thanks Keith. I found the MSDS below. Looks reassuringly benign. perhaps not the full story.

http://www.nttworldwide.com/docs/PCBsMonsanto-MSDS.pdf

I have read about industrial scale environmental problems in the States rgds residual pcbs threatening water supplies wherever manufacture and storage took place. Obviously the stuff had a great number of uses and was manufactured in huge quantities.

martin