What does Oxygen Free mean?

[Tallcane]

I see where some companies advertise their speaker cable to be oxygen free cable. What does this mean? Is it worth looking for? Is it snake oil? What is the deal?

I am going to do some home theater in wall installation and was going to use some Blue Jean cable 12/2 or some impact acoustics 12/2 in wall cl3 rated wire, but an installer made a comment to me that they seek out oxygen free wire because it prevents corrosion. Is this correct?

 

[Buckeyefan 1]

I see where some companies advertise their speaker cable to be oxygen free cable. What does this mean? Is it worth looking for? Is it snake oil? What is the deal?

I am going to do some home theater in wall installation and was going to use some Blue Jean cable 12/2 or some impact acoustics 12/2 in wall cl3 rated wire, but an installer made a comment to me that they seek out oxygen free wire because it prevents corrosion. Is this correct?

In high humid areas, copper can corrode. This is especially true if you live near the ocean. If you've ever stripped speaker wire and checked it months or years later, you'll see it darkens (or corrodes). There's little evidence that it causes any degradation in sound.

Most cable won't corrode inside a pvc/rubber jacket, so it's the tips that need attention. Most guys simply solder or crimp on a banana plug on speaker wire. RCA's/other types of connections already have ends.

 

[Tallcane]

What does oxygen free have to do with this concept? I could understand its importance if it what somehow sealed but it will be somewhat exposed on each end to make connections.

Do I need to seek out an in wall speaker cable that specifies oxygen free?

 

[jaxvon]

Oxygen free refers to a certain level of copper purity in the cable. I don't remember the spec, but once copper has a certain amount of oxygen or less in it, it's considered "oxygen free".

This is not a requirement for cabling. Normal annealed copper is already much more than 99% pure.

You'd be making a good choice going with either Impact Acoustics in-wall cable or Belden. If you decide to go with the Belden cable, it's much cheaper to order your cable from Westlake Electronic. It's only $0.21/ft (up from $0.17 a few months ago...grr).

 

[MDS]

The standard is '5 nines'; ie 99.99999% pure copper. Good luck trying to find any speaker wire that is NOT oxygen free by that definition.

A few companies like to promote it in their advertising as if it is something magical that distinguishes them from the competition when in reality they all use oxygen free copper.

 

[skipsterut]

I agree -- I've been looking at all kinds of cable from many sources in the last few days and I don't remember one NOT saying "oxygen free." Quickly got the idea that it's pretty much a common thing that everyone (or at least most) companies say because it "sounds cool and techie."

jaxvon -- as mentioned in another thread -- the Belden spaker cable from Westlake was a good deal -- I scored 200 ft @ $0.19 -- ordered Friday afternoon and delivered today (seems a little stiff -- but hey, it's 12# so great conductivity). Interestingly -- the original link in your post went to an SKU that showed just 150 ft available. I assumed this was just some kind of computer glitch and went ahead and entered 200 for the qty. It came back with "are you sure you want to backorder 50 ft?" NO! I then called the 800 # and the guy I spoke with was really great -- sounded like one of the owners, but I didn't ask. He checked the computer himself -- and sure enough they only had 150 ft in the 100 ft reels (which was the SKU I was linked to). "Did I want to wait until their replenishment order arrived?" NO, 'cause I need it in the next few days. OK, he said "Let me check something else." -- and he came back with the fact that they actually had plenty of the same cable in another SKU of 500 ft reels. He gave me the info I needed to order that SKU (which showed about 2,500 ft available) and the order went through without a hitch. Absolutely fantastic customer service -- especially if you're not willing to just believe what the web pages tell you if it doesn't make sense .

 

[jaxvon]

It is a tad stiff because it doesn't have the super super high strand count that the expensive cable has. That said, it doesn't conduct any better or worse and it's good stuff. I think since I started pimping it here it's been selling out faster and faster. It used to be I'd always see their quantity really high. I've seen them sell out of 2000ft in less than a day now. Crazy.

 

[Swerd]

Oxygen-free copper prevents brittle solder joints

After soldering on a connector, such as an RCA plug, to a cable, copper can become brittle where it was exposed to high temperature. Oxygen-free copper minimizes or eliminates this problem.

Look in the Audioholics article titled Component Video Cables - The Definitive Guide. It's long, but has a lot of good information that applies to more than just component video cables.

Look at Section 3.1 Conductor and Ground for a brief discussion of what oxygen-free copper is and why the industry uses it.

The fact of the matter is that OFC copper and pure unalloyed copper, both oxidize at around the same rates. Some cable manufacturers use the OFC as an advertisement that it will not oxidize, or it will oxidize less than other copper conductor materials, but there is no truth to these claims.​

Note that the copper industry did not develp OFC for audio use. It is most commonly used in plumbing for water supply pipes where joints are made by brazing or high temperature soldering. I was once told that OFC was first developed for use in the copper windings of large electric power generators. Non-OFC copper in these windings would fail after prolonged exposure to heat, vibrations, and high g forces. I don't know if that is really so, but it sounds reasonable.