Crossover box construction. Stainless?.

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I am bulding a speaker.

I will have my CAD designer and his CNC man carve a dragon 'head' into the front, and the 'body' into the side.

My crossover parts are heavy, as well as large. I will have a tail made. This tail will house the crossover.

My first thought was fiberglass. On second thought this may not be strong enough. The tail will be lifted if the speaker needs to be moved or transported.

I then thought of steel. My problem with steel is the possible effect it will have on the signal. The wires will run under this tail, with the parts on top. Possible future magnetization of the steel is also not good. (A fiberglass cover will be made to hide the parts).

I then thought of stainless steel. What are your thoughts.
 
Cousin Billy said:
If I assume copper is a material which can be picked up by a magnet, but aluminum cannot, then aluminum would be better?..
Neither copper nor aluminium can be picked up by a magnet. Most types of stainless steel are non-magnetic too. However, like MadMutt said, it is best to avoid metal of any type, since they will all have some effect on the inductors.

EDIT: More generally, avoid any electrically conductive material.
 
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MadMutt said:
keep the xover AWAY from any and all metal of any description.


Troels Gravesen has proved very clearly that even aluminium affects inductor value
He also shows how to get around it

I have heard of people having their their 2ways on metal standmounts, complaining about severe problems with sound
And when placing their speakers on a wooden chair they sounded just fine
 
Cousin Billy said:


I think I should also investigate fiberglass. Does anyone have any knowledge as to whether 1/2" thick fiberglass can withstand hundreds of pounds. The bottom of the speakers will also sit on it with spiked feet under that?.


Yes, but 1/2" fiberglass would be prohibitively expensive to buy in sheet form. Strength would be largely dependent on footprint/span, but prefab composite sheets are much stronger than comparable thicknesses of wood.

Depending on shape, you could reasonably do a 1/2" thick hand lay-up. It would need to be done a few layers at a time using epoxy resin to avoid getting too hot. Vacuum bagging would make a stronger and more appealing finished product. Hand -layed composites don't do sharp corners well without it.

Trouble is, fiberglass is flexible and wouldn't make a great speaker stand, IMHO. Carbon fiber is typically the stiffest of the composites.

Overall, I'd agree with MJL.
 
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1/2" fiberglass can withstand thousands of pounds

Smaller items with that thickness will not flex at all

Maybe better look at sandwich construction, a core and thinner fiberglass on each side
You can get very flexible core materials
Will be exstremely stiff and strong

But glassfiber is prone to static electricity, which is not good either
 
tinitus said:
1/2" fiberglass can withstand thousands of pounds

Smaller items with that thickness will not flex at all


You can get very flexible core materials
Will be exstremely stiff and strong

Certainly you could drive a car across it. I can stand on a 2' span of 1/8" thick 2" diameter glass/epoxy tube. But with "hundreds" of potentially vibrating pounds on top, wouldn't the enclosure dimensions be significant towards resonation?

Great suggestion about the sandwich material.

www.nida-core.com
 
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1/2" thick would do fore 30footer commercial fishing boat

It wont "move an inch", but nothing is completely dead and may ressonate

But shape is important part of the key to strength

Should I build a nice box today I would use vertical stacked plywood, and shape it like a sculpture, but acoustical sensible

Then you could make a mold from that, if you want, but it takes skills
 
I tried uploading pictures, pixel count too high. I tried lowering the pixels in Canon zoom browser but was unsuccessfull. I will assume I need to retake the pictures in a lower resolution. Not enough hours in the day. If anyone can help me with figuring this out, thank you.

Worst case scenario, there will be four Mundorf Zero Ohm transformers. These alone will weigh in at 40 pounds. There are also two Cast Pio, and four VSF caps. If you need a feel for what I am building, see Tony Gee's 'Humble Statement'. Where he uses lower quality caps for cost, I am not. 60 pounds per crossover may be low. If all of the LEAP parts are used, we will tip the scales at 80 pounds per speaker crossover. The speakers themselves without the drivers are already 70 pounds before glue and paint or front baffle. I may have an in for Jatoba hardwood, add another 50 pounds per speaker, minimum, otherwise white Maple will be used.

To recap; the speakers will have a Dragon etched into the wood/MDF, front and side. The 'tail' will finish the Dragon theme. The speakers will sit on this tail, spikes for claws, with the tail extending out from under the speakers, up about two feet, and then back down to the ground. I will have the tails touching the ground for added support. All wiring will extend out past the end of the tail (16") and be directly attached to the Atma-Sphere MA1 amps. Once final positioning in the listening room (under construction) has been determined, the wires will be hardwired into the amps.

The wireing will be UPOCC Silver for the tweeter and mid, with Mundorf Silver Gold wire for the woofers. The -ve run of the tweeter and woofer will be continuous from the driver to the amps. The +ve run for the mids will also be uninterupted. The crossover parts will be on top of this 'tail', with the wire running underneath. There will be no binding posts, and there will be no solder. My best friend makes jewelrey. He will be using molten sterling silver and flux to make all connections. Very dangerous, and not to be attempted. His jewellrey is spectacular.

As you can see, this is an over the top speaker. Total cost to date before assembly is nearing $22,000.00 US. Final price is still well below what I would have paid for top flight speakers.

I have put word out to some Kevlar companies that I need the tails built. If I assume the worst, a company making Kevlar canoes and Kayaks will have no problem making my tails. The canoes are in the $2,500.00 range, so I am budjeting for that.

With all the crossover testing still to be done, I expect a finished speaker mid August.

I think I will start a website to chronical my adventure.

May I querry the moderators of this wonderful website if higher resolution pictures will soon be allowed?.

LOL Billy

PS Tinitus, treating the fiberglass with an anti-static coating is a great idea
 
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I hope you are joking :D

I hope you are very skilled with doing proper measurements, and know how to design a crossover, or all the money and top quality components in the world wont help you any bit

Anyway, if you really want only the very best, top of the line DCA/Jensen gold foil caps and inductors alone will eat up your budget very fast

Whats it gonna be good fore anyway
Do you have a certain purpos
 
Thank you for your concern Tinitus.

15 years ago I was suckered into starting a roofing company, with no experience at all, and three years after that I was the top 'independant' in the city. Today I run 5 crews out of my truck. We do $1 mill a year, and I am the secretary, estimator, organizer, bookkeeper, and toilet bowl cleaner all in one. IMPOSSIBLE. Luckily for me my brain never stops working. I will surely die an early death.

My wife and I bought an old run down house. She now has a kitchen and a bathroom to die for. The rest of the house is just as spectacular. I have renovated my house with no previous experience. When an inspector came to look at my work (supporting wall removed), he told me not to bother calling him anymore, he approved everything without looking.

I took a ProAc Response 2 and rebuilt it many times. Countless variations. Countless crossover changes. MY EARS told me when I made a mistake. IF IT DOESN'T GIVE YOU GOOSEBUMPS, THERE'S SOMETHING WRONG. The 'Voicing' of these speakers will take months. I rebuilt a pair of B&W bookshelf speakers countless times. I turned it from a nice speaker to a great speaker. My ears will tell me when I have it right.

I have two independent LEAP design programs. Both are close but still a little different. Measurements will be taken every step of the way.

I once read here that speaker measurements should be taken 'in box'. Meaning forget what you have been told. I will take that one step further and say 'your amplifier/driver interaction' also needs to be taken into account. My amplifiers are the Atma-Sphere MA1, totally modded by the factory. They have an output impedence of 2.3 Ohms. This fact alone makes all previous "official" driver measurements useless.

Let me explain. These OTL amps make more power into higher impedences. The Accuton woofers have very high resistance at lower frequencies. A solid state amp will make less power at higher impedences. The OTL will make more power. For this reason I believe the woofers will behave differently then expected. To a lesser extent, but for the same reason, the mids and tweeters may also behave differently. Only measurements will tell the tale. I am in not hurry. Perfectionism is only a lifetime away.
 
Cousin Billy said:
I tried uploading pictures, pixel count too high. I tried lowering the pixels in Canon zoom browser but was unsuccessfull. I will assume I need to retake the pictures in a lower resolution. Not enough hours in the day. If anyone can help me with figuring this out, thank you.

Send them to me. I will downsize them in iPhoto.

Cousin Billy said:

15 years ago I was suckered into starting a roofing company

15 years ago I started a roof inspection company. Nice coincidence.
 
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