Quick question about wires and signal transmission. If I understand correctly, audio signal is AC and travels on the surface of the wire. I assume that the same principle as antenna would apply here. In that case, why is there such an obsession with the Origen free copper? Isn’t the diameter of the wire that will matter? Are there any scientific measurements that prove that OFC is superior to the copper clad aluminum or steel? Just curious.
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Speaker wire, CCA vs OFC
- Thread starter EDMLover
- Start date
Skin effect happens at RF frequencies. At audio essentially the entire depth of the wire is used. Speaker cables and interconnects do not function as antennae at audio frequencies. If you would like to construct a half-wave dipole, at 20 Hz it would be about 2000 miles long.
As for OFC (oxygen-free copper) vs. CCA (copper-clad aluminum), there are plenty of measurements showing the difference. CCA uses a thin layer of copper over an Al core and thus has much higher resistance than pure copper. In general, you'll need to buy 1-2 gauges larger (smaller AWG number) wire to provide the same resistance as pure copper. That is, if you need a 12 AWG wire, you'll need to buy 10~11 AWG CCA. Another issue is that the copper layer is thin enough on many wires that tightening a connection will strip the copper, potentially leading to worse connectivity. There is also an issue with dissimilar metals causing bad connections over time.
Many folk use CCA and it works just fine. I have personally had a few bad experiences with it (mainly for AC power operations, fewer with speaker cables) so tend to not use it. But it is cheaper than OFC if that is a concern. I figure I don't buy wire that often so don't mind paying the difference.
HTH - Don
As for OFC (oxygen-free copper) vs. CCA (copper-clad aluminum), there are plenty of measurements showing the difference. CCA uses a thin layer of copper over an Al core and thus has much higher resistance than pure copper. In general, you'll need to buy 1-2 gauges larger (smaller AWG number) wire to provide the same resistance as pure copper. That is, if you need a 12 AWG wire, you'll need to buy 10~11 AWG CCA. Another issue is that the copper layer is thin enough on many wires that tightening a connection will strip the copper, potentially leading to worse connectivity. There is also an issue with dissimilar metals causing bad connections over time.
Many folk use CCA and it works just fine. I have personally had a few bad experiences with it (mainly for AC power operations, fewer with speaker cables) so tend to not use it. But it is cheaper than OFC if that is a concern. I figure I don't buy wire that often so don't mind paying the difference.
HTH - Don
While the skin effect is real, it isn't relevant at audio frequencies.
Because the salesmen said so.
What matters is the resistance/impedance of the wire. Since the speaker impedance is only a few ohms, you want the wire to have only a small fraction of that so as not to waste power. Copper is a good wire material due to its high conductivity and agreeable mechanical properties. Aluminium is cheaper and lighter but difficult to connect electrically. Steel is stronger but has other deficiencies. Since neither price, weight, nor strength are limiting factors for domestic speaker wires, copper is a good choice. Oxygen-free copper is required some harsh industrial environments. For domestic use it makes no difference.
Last edited:
Speedskater
Major Contributor
From a conductor point of view, CCA is OK but it needs to be larger than a copper conductor. Say 12AWG CCA to 14AWG copper (and maybe more). Attaching connectors may be a real world problem.
As for expensive OFC compared to wire copper the difference it trivial! It's the difference between a 10 foot regular copper and a 10 foot 8 inch OFC copper speaker cable.
As for expensive OFC compared to wire copper the difference it trivial! It's the difference between a 10 foot regular copper and a 10 foot 8 inch OFC copper speaker cable.
sajunky
Active Member
Forget CCA. Buy a quality brand of pure solid copper Cat 5 Ethernet cable and you get OFC cable cheap. Refer to the datasheet and take an attention to the insulator material of individual wires. Teflon or PTFE variety is one of the best. Such cables are more expensive for a reason. Material for the outer plastic do not matter, it can be PVC, you can even strip it if you like).
I made my speaker cable from Cat 5 cable. Avoid a stranded (or patch) cable, as non-linear conductivity effect between wire strands degrade sound quality. For the stranded cable OFC reduce effect of copper oxidation, but not eliminate entirely.
I made my speaker cable from Cat 5 cable. Avoid a stranded (or patch) cable, as non-linear conductivity effect between wire strands degrade sound quality. For the stranded cable OFC reduce effect of copper oxidation, but not eliminate entirely.
watchnerd
Grand Contributor
I sometimes read how silver wire or silver-coated wire can sound "bright".
Is this complete BS or is there some conceivable validity to it?
Is this complete BS or is there some conceivable validity to it?
Complete BS of the purest variety. Doubly so for digital cables.
Speedskater
Major Contributor
While you can make a nice DIY speaker cable use several Cat cables:
a] It can be Cat3 or higher, Cat3 can be found at very low prices and there is nothing to be gained with higher Cat numbers.
b] For speaker cables there is no difference between Teflon, PTFE and PVC.
c] Nothing special about OFC.
d] Stranded wire would be a pain to hook-up. But it won't degrade the sound.
Parallel several Cat cables taped together. Hook all the solid colored wires to one terminal and a the striped wires to the other.
watchnerd
Grand Contributor
Isn't it just easier to buy some Canare star quad wire and terminate it?
It's not like it's expensive at $1.28/foot.
sajunky
Active Member
This is right, Cat 3 can be used too, but it is easier to find Cat5 cable with a quality insulation (Teflon, PTFE, the most common is polyolefin - still good). In practice it is a Cat 5 you will probaly find today, as I completely disagree with all your other points (b,c,d).
For all others, this (20 years-old) link is still the best source of audio DIY cables you can get. I do fully agree what the author - Thorsten Loesch - said there: The Naked Truth about Speaker-Cables
Last edited:
Speedskater
Major Contributor
Oh dear, oh dear.
What a mess.
* * * * * * * * * * * *
The things that really matter in loudspeaker cables:
a] The total end-to-end resistance with respect to the loudspeakers impedance curve.
b] For some special low impedance at high frequencies loudspeakers (like the Apogee's), low loop inductance.
c] For some amplifiers, reasonable total capacitance.
Last edited:
Speedskater
Major Contributor
Yep, there are several inexpensive solutions. But some people just like to DIY things and it can be a good speaker cable.
sajunky
Active Member
Really disappointing... You give people advice how to make Thorsten's FFRC cable and you don't understand technical objectives behind this design.
Amir has measured various 12 AWG wire:
https://www.audiosciencereview.com/forum/index.php?threads/when-12-gauge-wire-is-not-12-gauge.3/
I think 14 AWG is fine if you don't have to run wire across the house, and it's easier to work with than 12 AWG. The Belden 12 gauge stuff, in particular, is pretty stiff.
https://www.audiosciencereview.com/forum/index.php?threads/when-12-gauge-wire-is-not-12-gauge.3/
I think 14 AWG is fine if you don't have to run wire across the house, and it's easier to work with than 12 AWG. The Belden 12 gauge stuff, in particular, is pretty stiff.
sajunky
Active Member
I know these multistranded wires available in every TV shop and how they sound. You will enjoy it before finding something that sounds completely different. Trust me on this.
Or don't think they're particularly relevant.
For 99.9% of home installations, a run of #12 zip cord will work just fine.
jsrtheta
Addicted to Fun and Learning
Reminds me of the salesman quoted in The Audio Critic: "Of course, silver cable is faster!"
- Joined
- Apr 24, 2019
- Messages
- 1,501
- Likes
- 2,833
This is right, Cat 3 can be used too, but it is easier to find Cat5 cable with a quality insulation (Teflon, PTFE, the most common is polyolefin - still good). In practice it is a Cat 5 you will probaly find today, as I completely disagree with all your other points (b,c,d).
For all others, this (20 years-old) link is still the best source of audio DIY cables you can get. I do fully agree what the author - Thorsten Loesch - said there: The Naked Truth about Speaker-Cables
The linked article refers to Malcolm Hawksford's wire articles which have been proven to be very wrong (by real physicists).