Buying a cable to record ATC/intercom off GoPro

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smltk1

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smltk1
I am about to purchase a GoPro Hero 2 camera to record my flights and to serve as a dash cam for my car. I want to record the ATC in flight and after some Googling, I found this cable:

http://www.mypilotstore.com/MyPilotStore/sep/1978

Looks great and all, except the price. Almost $40 for an audio cable seem like a ripoff. I'm not 100% sure but I feel like a cable like this can be had for much cheaper, much like how you don't have to spend $100 on ripoff HDMI cables from Best Buy when $5 ones from Monoprice will do. Are there any other cables/alternatives that are a bit cheaper? I know of the one where you put earphones into your headset earcups but that sounds extremely uncomfortable and I'm doubtful that I'd be getting the best audio quality recording like that.

Thanks in advance.
 
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smltk1 said:
I am about to purchase a GoPro Hero 2 camera to record my flights and to serve as a dash cam for my car. I want to record the ATC in flight and after some Googling, I found this cable:

http://www.mypilotstore.com/MyPilotStore/sep/1978

Looks great and all, except the price. Almost $40 for an audio cable seem like a ripoff. I'm not 100% sure but I feel like a cable like this can be had for much cheaper, much like how you don't have to spend $100 on ripoff HDMI cables from Best Buy when $5 ones from Monoprice will do. Are there any other cables/alternatives that are a bit cheaper? I know of the one where you put earphones into your headset earcups but that sounds extremely uncomfortable and I'm doubtful that I'd be getting the best audio quality recording like that.

Thanks in advance.
Click to expand...


The problem with the comparison between this cable and the TV cable goes to "economy of scale." How many TV's are sold in a given timeframe? Now, how many pilots want a Video Camera connected to audio in the same time frame?
 
Can you just use a cheap microphone and place it in one of the ear cups of your headset?
 
Tex_Mike said:
Can you just use a cheap microphone and place it in one of the ear cups of your headset?
Click to expand...

Yes, that is an option. Some of the earlier linked threads have links to microphones for that purpose.
 
smltk1 said:
I know of the one where you put earphones into your headset earcups but that sounds extremely uncomfortable and I'm doubtful that I'd be getting the best audio quality recording like that.
Click to expand...

Bah - The problem with a cable is that you get ONLY radio chatter - No clue that you're in an airplane with an engine turning. IMO, the videos come out MUCH better when you can hear a bit of airplane noise in the background. The earbuds/mic in the headset trick means that the video will have EXACTLY the same sound that you hear when you're flying it, provided you use a decent setup (test before you go). I use the iPod/iPhone/whateveriGadget's white earbuds for this purpose, since I don't use them for anything else, and they work great.

The following was recorded on a Canon HV20 with a set of iPod earbuds in the earcups of my Lightspeed 20-3G headset:

 
I got the GoPro today and did a test with some standard earphones I got with my smartphone. I had to speak with the earphone literally on my mouth for it to actually pick up the audio. I also borrowed one of those iPod earphones and got the same results. How do people get good audio with this setup? It BARELY picked up anything when I placed it into some headphones I had laying around and played random ATC from LiveATC.
 
smltk1 said:
I got the GoPro today and did a test with some standard earphones I got with my smartphone. I had to speak with the earphone literally on my mouth for it to actually pick up the audio. I also borrowed one of those iPod earphones and got the same results. How do people get good audio with this setup? It BARELY picked up anything when I placed it into some headphones I had laying around and played random ATC from LiveATC.
Click to expand...

Put the mic in your EAR not near your mouth. Then the mic hears what you hear. Put it in the empty space between your headset and your ear.
 
flyingcheesehead said:
Bah - The problem with a cable is that you get ONLY radio chatter - No clue that you're in an airplane with an engine turning. IMO, the videos come out MUCH better when you can hear a bit of airplane noise in the background. The earbuds/mic in the headset trick means that the video will have EXACTLY the same sound that you hear when you're flying it, provided you use a decent setup (test before you go). I use the iPod/iPhone/whateveriGadget's white earbuds for this purpose, since I don't use them for anything else, and they work great.

snip
Click to expand...

Yes, I have the pricey cable and do not like that there is no cockpit noise. You can see the difference on my CTLS vs Luscombe landings on my YT.

Are you saying that iPod earbuds have a built-in mic??
 
alfadog said:
Are you saying that iPod earbuds have a built-in mic??
Click to expand...

Nope - But both earphones and microphones are simply transducers that convert between an electrical signal and a sound wave, so any pair of headphones can be used as a microphone (with varying results, see below). The simple version is that a pair of headphones uses an electrical signal to excite an electromagnet that moves to create sound, but if you speak into that same pair of headphones, the sound causes the magnet to move which creates an electrical signal. Any pair of headphones and any microphone can be used in either direction, though it's very easy to destroy a microphone if you try to use it as a speaker and different headphones will have different responses to sounds so the quality of recordings will vary with different models.

In recent history, I've always had spare iPod earbuds hanging around so I've always used them. AdamZ tried some different headphones with poor results and the iPod ones with good results, and since they're a dime a dozen and many people already have an unused pair sitting around, it's an easy recommendation to make.
 
flyingcheesehead said:
Nope - But both earphones and microphones are simply transducers that convert between an electrical signal and a sound wave, so any pair of headphones can be used as a microphone (with varying results, see below). The simple version is that a pair of headphones uses an electrical signal to excite an electromagnet that moves to create sound, but if you speak into that same pair of headphones, the sound causes the magnet to move which creates an electrical signal. Any pair of headphones and any microphone can be used in either direction, though it's very easy to destroy a microphone if you try to use it as a speaker and different headphones will have different responses to sounds so the quality of recordings will vary with different models.

In recent history, I've always had spare iPod earbuds hanging around so I've always used them. AdamZ tried some different headphones with poor results and the iPod ones with good results, and since they're a dime a dozen and many people already have an unused pair sitting around, it's an easy recommendation to make.
Click to expand...

Well, slap me silly, I never thought of that! I will give it a try.
 
kimberlyanne546 said:
Put the mic in your EAR not near your mouth. Then the mic hears what you hear. Put it in the empty space between your headset and your ear.
Click to expand...
I mentioned that I did exactly that in the last ssentence of my post.
 
smltk1 said:
My mistake.

These two is all I need then?

http://www.radioshack.com/product/index.jsp?productId=2102927
http://www.radioshack.com/product/index.jsp?productId=2102950

I'm more concerned with buying the proper plugs than the mic.

EDIT: Scratch the above. All I would need is the mic and plug it into the GoPro's audio port. What is the 1/8" plug used for?
Click to expand...

Sorry, 1/8 is the measurement of a "standard" plug (headset jack in cell phones, etc). An aviation plug (phone only, mic is slightly smaller) is 1/4"
 
The little box is a battery. It is for an amplifier in the mic that amps the sound.

Or you could do what I did:

1 Y-Splitter, mono to mono, 1/4"

1 1/4" to 1/8" cable

Plug the Y into the plane. Plug the heaset into half of the Y and the other plug left over in the plane. Plug the 1/8" into the other side of the Y and into your camera. Though that is a lot of wires.
 
smltk1 said:
Alright, so this is the 1/4" to 1/8", yes?

http://www.radioshack.com/product/index.jsp?productId=2062446

I'm unable to find the 1/4" mono to mono Y splitter, even searching Google. Can I get a link to that please? Thanks in advance.
Click to expand...

Do you have a physical store (Radio Shack)? I got mine all in store. Took a while, but you can ask a sales person.

No, your cable is not the right one.

The 1/8" is "male" and the 1/4" is "male". The male 1/8 plugs into your camcorder audio in jack or your hand held voice recorder audio in.

It is about a foot long (an actual cable). Yours was an adapter.
 
Mono is what I chose, old plane, not sure if stereo will work.

Is about $5 and looks like this:

41ls4XqHbcL.jpg
 
alfadog said:
I think the point of the OP was that he does not want to spend $40+ on a cable. :D

And wouldn't it be easier to connect directly or is your camera(s) mounted outside and/or no mic jack?
Click to expand...

I just wore my voice recorder around my neck, then the cables (so many) didn't bug me, they were already running from my head to my headset plug in within the panel.

I still haven't linked up the audio with the video, but it is fun to listen to in my car / brings back memories of the flight.
 
Yeah, I'm going to walk into my local Radioshock with this list. Thanks for your help, I appreciate it.
 
I just wanted to clarify, this cable setup is a DIY alternative to the cable I linked in the original post, yes? I won't be needing that mic?
 
smltk1 said:
I just wanted to clarify, this cable setup is a DIY alternative to the cable I linked in the original post, yes? I won't be needing that mic?
Click to expand...

I have the pricey cable but I am going to try the earbuds as mic trick so you can hear ATC and the engine both.
 
flyingcheesehead said:
In recent history, I've always had spare iPod earbuds hanging around so I've always used them. AdamZ tried some different headphones with poor results and the iPod ones with good results, and since they're a dime a dozen and many people already have an unused pair sitting around, it's an easy recommendation to make.
Click to expand...

Hi. I just tested a pair of iPhone earbuds as mic by recording while:

1. holding the earbuds quite close to my mouth to simulate being inside a headset and speaking quite loudly.
2. Speaking the same tone into the laptop mic which was almost two feet away.

The laptop mic, even though 20x distant, recorded quite a bit louder. Obviously it takes a lot less energy to drive the dedicated mic than to reverse-drive the earbuds.

Is that your experience? Does inceasng the volume in the edit process cause distortion issues in the finished vid?

Thanks
 
Yeap, that's how my experience was. I used a pair of AudioTechnica AD700s to simulate my headset and placed the earphones between the empty area between my ears and headset. I was barely able to pick up the same ATC audio I played on my computer and raising the volume just made the white noise (I think that's the term?) louder.
 
smltk1 said:
Yeap, that's how my experience was. I used a pair of AudioTechnica AD700s to simulate my headset and placed the earphones between the empty area between my ears and headset. I was barely able to pick up the same ATC audio I played on my computer and raising the volume just made the white noise (I think that's the term?) louder.
Click to expand...

What I am going to try is just sticking a small mic inside my headsets. I have the pricey cable and the setup you are putting together is basically the same thing. The problem is that you get ATC but no outside engine noise (see my KTMB landing on my YT). I would like to have some engine noise for "atmosphere".

Also, the reason you go with the expensive cable is that there is a huge impedance difference between your headset and the camcorder. If you just split the headset signal, I think you overdrive the camcorder.
 
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Inverted said:
Why do you want engine noise in there?
Click to expand...

Cause I like it.

OK folks, I do not know anything about audio. Here is what the specs for my camcorder say:

MIC Terminal​
​
​
​
​
∅ 3.5 mm stereo minijack​

–57 dBV (with 600 ohm microphone) / 5 kohms or more
I understand that GA headphone impedence is 150 - 300 ohms? So it would take less power to drive the headphones than to drive a 600 ohm mic? Also what does the 5 kohms in the spec refer to??
 
alfadog said:
Cause I like it.

OK folks, I do not know anything about audio. Here is what the specs for my camcorder say:

MIC Terminal​
​
​
​
​
∅ 3.5 mm stereo minijack​

–57 dBV (with 600 ohm microphone) / 5 kohms or more
I understand that GA headphone impedence is 150 - 300 ohms?
Click to expand...

The spec sheet for my headset says 600 ohms nominal.

So it would take less power to drive the headphones than to drive a 600 ohm mic?
Click to expand...

Normally, lower impedance implies more power, not less. The reason is that power is voltage multiplied by current, and with low impedance, a specified voltage produces more current.

Also what does the 5 kohms in the spec refer to??
Click to expand...

I'm an electrical engineer, but I don't know what they're trying to say on that "–57 dBV (with 600 ohm microphone) / 5 kohms or more" line.
 
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Palmpilot said:
The spec sheet for my headset says 600 ohms nominal.



Normally, lower impedance implies more power, not less. The reason is that power is voltage multiplied by current, and with low impedance, a specified voltage produces more current.



I'm an electrical engineer, but I don't know what they're trying to say on that "–57 dBV (with 600 ohm microphone) / 5 kohms or more" line.
Click to expand...

The reason they try to get you to buy the $40 cable instead of splitting like Kim did is impedance matching. Kim, how does your system work out for you?

Here is one similar to what I bought:

http://www.barnstormeraudio.com/IRC.html

The IRC0014 series intercom recording cables addresses the problem of attempting to use a standard microphone interface to record a signal intended to drive a 600 ohm aviation headset. The integrated electronic circuitry steps the signal down to levels expected by the recording device, preventing oversaturation of the recording device and thereby eliminating any distortion.

Additional protection is provided via AC coupling, ensuring that only the audio signal is passed while DC power remains isolated to the respective equipment. At low levels, DC power interference can reveal itself as a high-pitched squeal in the recorded audio. If enough voltage is present, irreparable equipment damage can occur
 
smltk1 said:
I just wanted to clarify, this cable setup is a DIY alternative to the cable I linked in the original post, yes? I won't be needing that mic?
Click to expand...

Yes as long as your camcorder has an audio in jack.

You can always return everything if it doesn't work, and each item costs only $4 - $6 (there are two items).
 
alfadog said:
The reason they try to get you to buy the $40 cable instead of splitting like Kim did is impedance matching.
Click to expand...

I've generally found impedance matching to be unnecessary when connecting a microphone input to a low impedance output. When it works, the reason is as follows:

1. A low impedance output will have a low voltage, because it doesn't take much voltage to deliver the desired power level into a low impedance load;

2. Microphone inputs tend to have high gain, so they don't need much voltage;

3. Many low impedance outputs work fine with little or no load; if not, then one can make an adapter that connects either a load resistor or a headset in parallel with the microphone input.
 
Palmpilot said:
I've generally found impedance matching to be unnecessary when connecting a microphone input to a low impedance output. When it works, the reason is as follows:

1. A low impedance output will have a low voltage, because it doesn't take much voltage to deliver the desired power level into a low impedance load;

2. Microphone inputs tend to have high gain, so they don't need much voltage;

3. Many low impedance outputs work fine with little or no load; if not, then one can make an adapter that connects either a load resistor or a headset in parallel with the microphone input.
Click to expand...

But isn't the issue that the output from the panel that drives the headset is designed for high impedence = higher power than the camcorder can handle or ???

If I have two speakers, one 8 ohm and one 80 ohm and drive them with the same output, won't the 8 ohm speaker be much louder?

Now if I have a mic input designed for 8 ohm instead of a speaker and drive it the same as 80 ohm, won't the mic input be relatively high?

Like I said, audio is not my strong point. Actually, electricity is my weak area.
 
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