Explain induction recording

P

Peeplmoovr

Member
I tried looking through forums for this info but couldn\'t find it.
My almost nonexistent understanding of induction has me thinking it involves using a mono recording right from a speaker source in park. How exactly does this work? (without geeking out too much - I\'m not an engineer as you can probably tell from this question). Does it record from the output of the speaker, or some other way?

Thanks.
 
In laymans terms, an induction recording uses a pickup device that measres the magnetic field around a speaker magnet, NOT the actual sound coming from it.

Radioshack sells them for about $8 or so I think. They are normally a MONO recording as the speakers they are recorded from are not usually stereo.

There is often a lot of \"noise\" associated with an induction recording that needs to be removed in post processing.

One of my best induction recordings is my 2006 Epcot Entrance Loop, and the Expedition Everest Area Music Loop. Both were done with a telephone pickup (induction mic) and a camcorder.

There is only one stereo induction recording that I know of, and that\'s my Song of the Rainforest which was recorded as two seperate streams and then assembled.
 
I think some recorders (e.g. Edirol) record a mono track in stereo.
 
I would guess that it just \"copies\" the left channel to the right.

I\'m not familiar with the Edirol device, but it does record some good stuff!

If you\'re looking for a device, I would suggest either the Edirol or a minidisc recorder. I\'m using a Sony RH1 currently
 
I may be looking, so thanks for the advice. I live near WDW and I\'d like to make some recordings - both for myself and to share with others - and I\'m looking for a decent way to do it without spending a fortune. :)
 
Peeplmoovr said:
I\'m looking for a decent way to do it without spending a fortune. :)
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That\'s the tough part... There are a number of cheaper minidisc devices, you can probably get them off eBay in the $150 range. I would suggest NOT using a camcorder to record, they often have limited audio options, and the worst is AGC (Automatic Gain Control) and also usually no method for line in. I record just about everything via line in using a battery box to power the microphones. This allows for a wider range of volume. The same mics I use going through the mic in port will quickly overpower the mic resulting is a bunch of static in the recording.

Again, I keep threatening to put up a tutorial, one of these days I will. Just need a little time ot sit down and work it out (as well as take some pictures) of my setup.
 
for my binaurals I use an iriver ifp899 (1 gig) drive .. but it\'s not longer sold ... it\'s perfect / phantom voltage / manual input volume control/ exchangable battiery (1 AA holds up to 40h\'s straight)

I hope it never breaks :-O
 
Quick question, if I use an mp3 player to do a line-in induction recording that encodes in .wav format, will it have good quality sound?
 
depends on the electronics..sometimes even uncompressed wave recordings sound bad when the A/D converter and signal processing is cheap

I guess you ust have to try it
 
Induction doesn't work in the line in port on devices. Induction pickups work on the mic-in, so that will probably NOT work. I honestly haveen't tried it, but I think you will need to power the induction mic to work, and that sortof defeats the purpose of using the speaker's magnetic/electronic signals to record.

By mp3 player do you mean iPod? I've been meaning to try mine to record, but I just haven't gotten the time to work with Podzilla. I'm thinking there are other ways to get an iPod to record (4th gen) but now that I have my minidisc recorder, it's been a little tough to justify the time.

All induction pickups will introduce some "noise", be it the normal induction hum, as I like to call it) or other interference. YOu'll need to clean it up regardless, however in theory, WAV should give you a better starting point, but I've seen 320 kbps MP3 clean up very nicely, and I'm using ATRAC 256 on my recordings and I think they sound great as well.
 
Induction doesn't work in the line in port on devices. Induction pickups work on the mic-in, so that will probably NOT work. I honestly haveen't tried it, but I think you will need to power the induction mic to work, and that sortof defeats the purpose of using the speaker's magnetic/electronic signals to record.
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thought induction devices work wih some small blackbox converting it to highpass line in -_-
 
That's not how I do it. I plug it right into the mic in on my recorder. I use a battery box for my microphones though. I haven't tried to do that with the induction pickup.
 
So I'll be going to WDW in 4 weeks and I want to record some music...Does anyone know where to get a good induction device (or something to limit the background noises) at a fair price? I've been looking around for a while and couldn't find what I was looking for. And if possible, would any devices would work well recording music from the ceiling too?
Thanks!
 
I think most of us use the telephone pickup from Radio Shack or similar. Search telephone pickup on Amazon. All pretty similar to each other (and buy a spare or two as sometimes you get a dud and they are cheap). Directional mics for out of reach speakers but I'm sure you'll get some more advice on those (I only use the ones on my Zoom recorder for reference recordings)
 
SamH said:
. And if possible, would any devices would work well recording music from the ceiling too?

Thanks!
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Be careful. At best you'll get funny looks. At worse security will be involved.
 
Radio Shack stopped selling telephone pickups around a couple of years ago. :(
That's why this seller is charging $28 and has only 1 left.  The pickup's original price was $8-$9.
https://www.amazon.com/Removable-Telephone-Pickup-Recorder-44-533/dp/B00114LCT2

These generic telephone pickups are much cheaper and they are an example of 'you get what you pay for'.  8)
http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-36-010-/36-010
They are less sensitive than the Radio Shack pickups by ~6 dB.  Depending on the recorder's noise floor and the strength of the speaker's magnetic field, that can be the difference between an acceptable recording or a not-so-good recording.  You can find various vendors selling these same induction pickups, usually at a higher price.
 
marni1971 said:
SamH said:
. And if possible, would any devices would work well recording music from the ceiling too?

Thanks!
Click to expand...
Be careful. At best you'll get funny looks. At worse security will be involved.
Click to expand...

To get a few reference recordings at DLRP from ceiling speakers at DLRP. I used my iPod which looks just like a mobile phone (I did it in 3 twenty minute sessions to get it all) and apart from nodding and occasionally silently moving my lips as if speaking, managed to get an identifiable recording of the loop standing under the speaker whilst paying inordinate attention to the menu on the wall. Nobody paid any attention to me but I ffelt really vulnerable but it was most satisfying to get it (the restaurant was the Last Chance cafe and very noisy..
 
pixelated said:
Radio Shack stopped selling telephone pickups around a couple of years ago. :(
That's why this seller is charging $28 and has only 1 left.  The pickup's original price was $8-$9.
https://www.amazon.com/Removable-Telephone-Pickup-Recorder-44-533/dp/B00114LCT2

These generic telephone pickups are much cheaper and they are an example of 'you get what you pay for'.  8)
http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-36-010-/36-010
They are less sensitive than the Radio Shack pickups by ~6 dB.  Depending on the recorder's noise floor and the strength of the speaker's magnetic field, that can be the difference between an acceptable recording or a not-so-good recording.  You can find various vendors selling these same induction pickups, usually at a higher price.
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Sorry, that was the wrong link. A search on Amazon brings uo many more from under $4  which look very like the Radio Shack one.
https://www.amazon.com/Telephone-Microphone-Suction-Cup-Pickup/dp/B0034I75IK/ref=sr_1_2?s=electronics&ie=UTF8&qid=1480379560&sr=1-2&keywords=telephone+pickup
 
eyore, your link points to the generic one which is less sensitive.  You can see on that Amazon web page that it is from the same manufacturer, MCM, as the link I posted.

The MCM telephone pickup does have the same overall shape as the Radio Shack pickup but the MCM pickup has lower quality parts & workmanship on the inside.  I've opened both the Radio Shack and MCM pickups to fix broken wires (the cable gets pinched where it enters the pickup body).

The MCM pickup also does not have the rubber pads that the Radio Shack pickups do, to help isolate the induction coil and its metal core from mechanical vibration.  If the speaker cabinet is vibrating at the right frequencies and the pickup is touching the cabinet, those vibrations will be transmitted to the coil as distortion.

So even if the incoming levels are well below clipping, the recording can have distortion.  I think that's what happened with 772pilot's induction recording of "Disneyland Forever".  Certain frequencies in "Kiss Goodnight" are distorted even though the levels are safely below 0 dB.

Another example are my induction recordings of the onboard audio for "Ghost Galaxy".  I used a Radio Shack pickup that was firmly attached to the speaker so it wouldn't come off during the ride.  SuperHotLarry could hear distortion in the very loud segments of the recorded audio and the speaker enclosure did noticeably vibrate during those sections.
 
I suppose that, with advancing age, I'm less sensitive to some frequencies as I just don't hear these problems any more and don't have the equipment to measure stuff.In the same way most lossy files sound pretty good to me too (mind you, I never heard the difference between a standard record player and a hi-fi system costing as much as a small car either. Probably a good thing I don't make recordings any more :D.
 
It's not frequency sensitivity that is the problem (i.e., an issue with spectral response) but signal strength sensitivity.  I.e., the MCM pickups are quieter by ~6 dB compared to a Radio Shack pickup.
 
Thank you all for the links! I'll be sure to grab one whenever I get the chance.
and yeah don't worry I won't be climbing off the walls to get the audio; Don't think I'm that desperate to get it haha. But was just wondering if it was possible since some of the audio speakers are on the ceiling only  :-[
The music in the line will have to do :)
 
What kind of recorder are you using?  You should test whichever induction pickup you end up buying with your recorder to see if you get a decent signal from a speaker at home before you try it for the first time (and under pressure) in a theme park. 8)
 
pixelated said:
So even if the incoming levels are well below clipping, the recording can have distortion.  I think that's what happened with 772pilot's induction recording of "Disneyland Forever".  Certain frequencies in "Kiss Goodnight" are distorted even though the levels are safely below 0 dB.
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Actually, it's because that recording was totally blown out prior to running it through a declipper.
 
pixelated said:
What kind of recorder are you using?  You should test whichever induction pickup you end up buying with your recorder to see if you get a decent signal from a speaker at home before you try it for the first time (and under pressure) in a theme park. 8)
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Well what type of recorder should I use? I'm all new to these things so I honestly have no idea what to do haha.
So I buy the one of the telephone pickups, and then a recorder then?
 
SamH said:
Well what type of recorder should I use? I'm all new to these things so I honestly have no idea what to do haha.
So I buy the one of the telephone pickups, and then a recorder then?
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How much money are you willing to spend?  It's the usual tradeoff with audio gear: spending more money gets you better electronics inside the gear and so you get better quality recordings.  If you want to spend the minimum amount of money, you need to know the minimum quality of audio that is acceptable to you.

You now have 3 weeks before you go to WDW.  Unless you can find a retail store to buy a recorder and a telephone pickup, you'll have to buy them online and wait for delivery.  Then you have to learn how to use the recorder to make decent quality recordings, whether using a normal audio mic or the induction mic.  That's a lot of work to do in 3 weeks. 8)
 
772pilot said:
pixelated said:
So even if the incoming levels are well below clipping, the recording can have distortion.  I think that's what happened with 772pilot's induction recording of "Disneyland Forever".  Certain frequencies in "Kiss Goodnight" are distorted even though the levels are safely below 0 dB.
Click to expand...
Actually, it's because that recording was totally blown out prior to running it through a declipper.
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Oooooo nooooo...  Where's that Edvard Munch's 'The Scream' emoji when you need it? ::)
http://www.iemoji.com/view/emoji/28/smileys-people/face-screaming-in-fear
 
pixelated said:
SamH said:
Well what type of recorder should I use? I'm all new to these things so I honestly have no idea what to do haha.
So I buy the one of the telephone pickups, and then a recorder then?
Click to expand...
How much money are you willing to spend?  It's the usual tradeoff with audio gear: spending more money gets you better electronics inside the gear and so you get better quality recordings.  If you want to spend the minimum amount of money, you need to know the minimum quality of audio that is acceptable to you.

You now have 3 weeks before you go to WDW.  Unless you can find a retail store to buy a recorder and a telephone pickup, you'll have to buy them online and wait for delivery.  Then you have to learn how to use the recorder to make decent quality recordings, whether using a normal audio mic or the induction mic.  That's a lot of work to do in 3 weeks. 8)
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Well my limit is over $100 but I would prefer if it were $30 and lower if possible. My ideal quality isn't so high that it sounds like it was the source audio- Just something good enough to listen to the song with limited background noises/clearer music.
 
If you want to make induction recordings, you'll need a recorder that has a good enough preamp to boost the signal from the pickup to a usable level for the recorder's electronics.

Digital voice recorders cost $20-60 and are meant for audio notes/dictation, recording lectures & interviews, etc.  They work with external condenser mics by supplying a small voltage to a preamp that is built into the condenser mic.  Induction pickup don't have that internal preamp so they may or may not produce a strong enough signal to produce a good recording with a digital voice recorder.  You may ask "Can't you just turn up the volume if the signal is weak?"  Yes, increasing the gain will boost the signal level but it will also boost any inherent noise in the recording from the recorder's electronics as well.  What you want is a good high signal-to-noise ratio (SNR) and not just a louder recording.

Digital PCM audio recorders are anywhere from $100-$1000 and are targeted at audio professionals like musicians, recording engineers, etc.  The preamps in these types of recorders usually have enough gain to work with induction pickups.


SamH said:
Just something good enough to listen to the song with limited background noises/clearer music.
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Unfortunately that is very subjective.  Also, "limited noise" and "clearer music" compared to...?  What are you using as a basis of comparison?

If you have music format conversion software on a computer, try picking some favorite tunes in various styles of music and converting them to a series of MP3s with progressively lower bitrates.  E.g., 320 -> 256 -> 192 -> 128 -> 64 -> 32 kbps.  Listen to the converted tracks and try to find out where the decrease in bitrate really does bother you.
 
pixelated said:
If you want to make induction recordings, you'll need a recorder that has a good enough preamp to boost the signal from the pickup to a usable level for the recorder's electronics.

Digital voice recorders cost $20-60 and are meant for audio notes/dictation, recording lectures & interviews, etc.  They work with external condenser mics by supplying a small voltage to a preamp that is built into the condenser mic.  Induction pickup don't have that internal preamp so they may or may not produce a strong enough signal to produce a good recording with a digital voice recorder.  You may ask "Can't you just turn up the volume if the signal is weak?"  Yes, increasing the gain will boost the signal level but it will also boost any inherent noise in the recording from the recorder's electronics as well.  What you want is a good high signal-to-noise ratio (SNR) and not just a louder recording.

Digital PCM audio recorders are anywhere from $100-$1000 and are targeted at audio professionals like musicians, recording engineers, etc.  The preamps in these types of recorders usually have enough gain to work with induction pickups.


SamH said:
Just something good enough to listen to the song with limited background noises/clearer music.
Click to expand...
Unfortunately that is very subjective.  Also, "limited noise" and "clearer music" compared to...?  What are you using as a basis of comparison?

If you have music format conversion software on a computer, try picking some favorite tunes in various styles of music and converting them to a series of MP3s with progressively lower bitrates.  E.g., 320 -> 256 -> 192 -> 128 -> 64 -> 32 kbps.  Listen to the converted tracks and try to find out where the decrease in bitrate really does bother you.
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Yeah I looked into PCM before and it was way too expensive for me. A Digital Voice Recorder would probably do best in this case.
And when I meant by limited noise I meant something something like limited ambiance background noise if that clears it up? Like  near or close to this type of quality; https://www.youtube.com/watch?v=fpHHBBSfJkg Sorry for the confusion.
 
SamH said:
Like  near or close to this type of quality; https://www.youtube.com/watch?v=fpHHBBSfJkg
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That YouTube video has a good quality induction recording.  If you're very lucky, you'll plop the induction pickup on a speaker and your induction recording will be that good.

Otherwise, you'll have to learn at a minimum:
- which speaker to use if more than one are playing the audio you want
- where to put the pickup on the speaker
- how to keep the pickup from moving because that causes audible glitches or shifts in volume and/or tone
- how to not look suspicious while doing all of the above 8)

And then there is the post-processing of your recordings but that can wait until you get home.
 
pixelated said:
SamH said:
Like  near or close to this type of quality; https://www.youtube.com/watch?v=fpHHBBSfJkg
Click to expand...
That YouTube video has a good quality induction recording.  If you're very lucky, you'll plop the induction pickup on a speaker and your induction recording will be that good.

Otherwise, you'll have to learn at a minimum:
- which speaker to use if more than one are playing the audio you want
- where to put the pickup on the speaker
- how to keep the pickup from moving because that causes audible glitches or shifts in volume and/or tone
- how to not look suspicious while doing all of the above 8)

And then there is the post-processing of your recordings but that can wait until you get home.
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Oh believe me there are many speakers throughout the area, I know many ways to access it without sticking out (I hope).
And yeah I did check that out but I would prefer if there would be a cheaper device ? If possible. And say I did buy this or something very similar; How might this appear on the X Ray machine for the airport/WDW? (I think WDW already has these or I'm confusing them with UOR?).
 
Nobody has ever queried it for me nor any of the electrical stuff I've taken either through customs security no the hotels nor park security. My recorder is in a small camera bag with a spare induction mic, earphones,SD cards and spare batteries. I also carry a minidisc recorder, an iPod and two mp3 players.,  I suppose it depends on what they are looking for. This is flying from the UK to DLRP when France was on high alert. Airport security sometimes ask if I have any electrical equipment or computers but have never asked to look at them.
 
I also have not had any problems taking my various electronic devices through security.  I think as long as the X-ray scanner operator can clearly see each device, you shouldn't have any problems.  I.e., don't jam them together.

The TASCAM is one of the cheaper PCM recorders.  As I said in an earlier post, using an induction pickup with a digital voice recorder may not work because the signal level is too low to give you a usable recording.  You won't know until you actually try it.  If the signal is indeed too low, then you have to buy another recorder and hopefully be able to return the original recorder.
 
pixelated said:
I also have not had any problems taking my various electronic devices through security.  I think as long as the X-ray scanner operator can clearly see each device, you shouldn't have any problems.  I.e., don't jam them together.

The TASCAM is one of the cheaper PCM recorders.  As I said in an earlier post, using an induction pickup with a digital voice recorder may not work because the signal level is too low to give you a usable recording.  You won't know until you actually try it.  If the signal is indeed too low, then you have to buy another recorder and hopefully be able to return the original recorder.
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Alright, I'll see what I can do.
Thank you for your help!  ;D
 
I know this thread is old but I've found it interesting. After reading all of the advice and caveats, not sure if it's worth the effort, but if someone were starting to dabble with an entry-level digital recorder and telephone pickup in 2021, what would the preferred recorder brand be--Zoom, Tascam, or something else entirely?
 
Doddles said:
I know this thread is old but I've found it interesting. After reading all of the advice and caveats, not sure if it's worth the effort, but if someone were starting to dabble with an entry-level digital recorder and telephone pickup in 2021, what would the preferred recorder brand be--Zoom, Tascam, or something else entirely?
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I bought a Sony PCM-D50 on pixelated's recommendation. Its preamp is supposed to be better than the ones used by Zoom and Tascam. I made a few test induction recordings from a speaker here at home, and they turned out quite nicely.
 
Back in the early 70's I used to make induction recordings using a suction cup microphone recording device for old telephones I got from Radio Shack and a cassette recorder. We had no special name for it. But it was magic!
 
I've had great success removing the suction cup from one of my pickups and gluing a rare earth magnet to it. No interference either.
 
disneydon said:
Back in the early 70's I used to make induction recordings using a suction cup microphone recording device for old telephones I got from Radio Shack and a cassette recorder. We had no special name for it. But it was magic!
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How Bowers says it was Mike Lee who thought of using a Radio Shack telephone pickup to record a speaker's magnetic field.  Is that correct?
 
Not sure but I was doing it back in 1974. I believe that's when my earliest tape was recorded. I believe I recorded Peoplemover, Haunted Mansion and Adventure Thru Inner Space in that first tape. Awwww the memories.
 
I saw someone was using an Edirol/Roland R-09 and had good results and there was an inexpensive one on eBay, so that’s where I’m starting. Now to find a suction cup . . .
 
Is there a list anywhere of easily accessible speaker locations? Feel like that could be helpful instead of everyone having to hunt for a signal on their own each time as they visit the parks.
 
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