Cable Length, Capacitance, does it matter? A test.

[zemlin]

I've been hearing a lot of talk about low capacitance mic cables and how much better they sound - that got me wondering. I know the Canare L4E6S is fairly high (46 pf/ft), but what does that really mean to me?

I put one of my trusty Oktava MK012s face to face with the tweeter on one of my monitors. Ran a 15' Canare cable to the Mackie 1402 mixer I user for routing in my studio.

In Audition I created a 1-second white-noise sample. I also added 3 single-sample ticks.
I recorded that sample through the 15' Canare cable.
I then chained a bunch of Canare cables together totalling 260' and recorded the exact same sample under the exact same conditions (except the lenth of wire).

Here are the resulting recordings.
http://www.cheap-tracks.com/mp3/15_foot_canare.wav
http://www.cheap-tracks.com/mp3/260_foot_canare.wav
The files are 24-bit packed - I can upload a different format if this gives folks trouble.

I used Adobe Audition to analyse the files. Frequency plots are almost identical They begin to deviate a fair amount when things get below 25 Hz (not much material down there as I was recording the tweeter). Also, there is a small deviation between the two recordings a few hundred hertz either side of 1800. Other than that they are line-on-line.

The recordings do not null when one is inverted on another, but the resulting file seems to be uniform in frequency distribution. If I zoom in on the timeline to where there are only a few samples on the screen, I can see a definite delay - apparently due to the length of the cable - on the 260 ft sample. The delay is too small for me to measure - nor do I think I can compensate for it in the software. This delay, however, would expain why the files do not null.

Anyway - do your own comparison. - analyze, A/B test, etc.
Share your thoughts.

[NA-UL]

there is a f@#$'ing jungle of cables behind my console ... and i was wondering if it would be worth modifying witch im assuming isn't to difficult... or would i be better off zip tying them in small coils to the back of the console... could this create noize?

[peeder]

Not surprised you aren't seeing any difference in the cable lengths at mic level.

Don't coil your cables, coiling is how they make antennas etc.

[PheelTheMusic]

In practical application, could running lets say a 25' mic cable for one drum overhead and a 50' cable for the other overhead mic cause time alignment/phase issues???

[peeder]

Originally Posted by PheelTheMusic

In practical application, could running lets say a 25' mic cable for one drum overhead and a 50' cable for the other overhead mic cause time alignment/phase issues???

Cables apparently transmit signal roughly 70% of the speed of light.

How much phase variance that is over 25 feet is something you can solve with some math.

I imagine the phase variance is about a millionth of a degree at 20KHz...

[PheelTheMusic]

Originally Posted by peeder

Cables apparently transmit signal roughly 70% of the speed of light.

How much phase variance that is over 25 feet is something you can solve with some math.

I imagine the phase variance is about a millionth of a degree at 20KHz...

light. is pretty fast.

[peeder]

Originally Posted by PheelTheMusic

light. is pretty fast.

Well Satchel Paige said that Cool Papa Bell was fast enough to turn out the lights and be in bed before the room got dark. stike

[Phil Cibley]

Originally Posted by NA-UL

small coils to the back of the console... could this create noize?

Don't coil them. They make much better RF antennae when coiled. Cut them to
the proper length.

[nosebleedaudio]

One thing to consider is signal source; if it's a line lever source it will be effected less than say a dynamic mic.
I would do the same test with a 15Khz tone thru a speaker cab and mic with a dynamic mic and see the difference in HF loss.
And some mics load easier than others...
That's why mic cables are far more important to have as short as possible.

[Brent]

Originally Posted by peeder

Well Satchel Paige said that Cool Papa Bell was fast enough to turn out the lights and be in bed before the room got dark. stike

Pfft I can do that ( but the lamp is beside the bed )

[Ear 4 Gear]

Originally Posted by peeder

Well Satchel Paige said that Cool Papa Bell was fast enough to turn out the lights and be in bed before the room got dark. stike

Depends on the size of the room. If the room is big enough, the RT60 Time for light might me long enough to go to bed

[WTMNMF]

If you are interested in actually understanding this subject, then I'll refer you to Stephen Lampen's excellent Audio/Video Cable Installers Pocket Guide (ISBN:0-07-138621-1).

There are one or two mislabeled illustrations and the description of a half-normaled patchbay is reversed. I'm sure that these were simply editorial errors.

The book will give an excellent technical and practical understanding of how cable construction and usage effect your signal integrity.