Thursday, May 28, 2009

Audio breakout cable for ipod/iphone

(update) I inadvertently said I got the 4 conductor plug at Jameco - it was Mouser, and is listed correctly, with the part number in the blog.

Have you ever wanted to plug in a professional studio mic to your ipod touch/iphone? There may be a commercial solution, but I couldn't find one. Even if there is one, I figured I could build one cheaper than a ready-made one. You could also use this for a line-in (my original reason for the project), but the source really needs to be taken down to mic level from line level for good sound quality.



The hardest part was finding the 3.5 mm 4 conductor plug (found it at Mouser, #171-7435-EX). The soldering to the plug was a bit tricky too. I needed a cable with at least 4 conductors inside, and I wanted to build this for next-to-nothing, so I used some CAT5 ethernet cable I had. CAT5 has 8 conductors, so if you know of any other common cable with at least 4, you can use that.

I've included a rough wiring diagram below.
***UPDATE: Thanks to PTM for pointing out the ipod/iphone's audio input is meant for an electret mic. Therefore, there is 2.7 v across the input. However, there is only .73 mA of current. If this concerns you and you want to get in the habbit of doing it the right way, you should put a 1 - 10 uF cap like this one in-line to block the dc. If you don't know how or want to do this, the current probably won't do any damage, but be warned.***

The sound quality with a Shure SM58 plugged into the ipod touch was way better than a very good pair of Shure earbuds/mic. When you look at the files in Sound Forge etc., the noise floor was about -60dB with the SM58 and about -50dB with the ear buds. The SM58 had way more dynamic range and obviously less background noise too. Not that surprising, since it's a professional mic, but more proves that for serious recording, this is well worth doing.

The earbuds/mic aren't terrible. It's more a question of "how good" do you need to get? On a pair of normal home computer speakers, there may not be as much of a difference, but I'm listening through a $1400 pair of Event studio monitors.

Here's the sound files to compare. They were recorded with the free Griffin iTalk app at 44.1k and file transferred directly via wifi :


71 comments:

  1. Any chance you can give the Jameco part numbers?

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  2. I did the same for a N95 to use a proper mic since the inbuilt one is worthless for making video with - I think the ground and mic connections were the other way around tho - Its not here to check but I toned out the supplied AV out cable to find which was the ground on it.

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  3. A Jameco part number would be excellent - I searched their catalog but couldn't turn up the appropriate plug.

    I've tried using a 4-conductor "AV" cable but it doesn't work with the 2G iPod Touch. I ended up buying a Thumbtacks mic, but it has the disadvantage of not being able to plug in headphones while using it, so this would be excellent!

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  4. I've been searching for that plug forever! Please post the part!

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  5. What about USB cables? They got 4 wires, AFAIK, and you surely have a lot around your house.

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  6. There is a company making this adapter and also the opposite:

    http://www.showmecables.com/viewItem.asp?idProduct=8335

    Use you iPhone headset for Skype & other voip:

    http://www.showmecables.com/viewItem.asp?idProduct=8183

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  7. Here is a 4 conductor 3.5mm male plug:

    http://www.showmecables.com/viewItem.asp?idProduct=3099

    4 conductor 3.5mm female jack:
    http://www.showmecables.com/viewItem.asp?idProduct=4074

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  8. i've been trying to do this with my ipod nano, but apparently the apple earbuds whith microphone are the only ones able to manage this.. can anyone confirm this? and why do these little pushpin microphones do work? (google: thumbtack nano and you will find it) is there some special chip i'm missing? or impedance?

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  9. How well does the 3.5 mm 4 conductor plug fit into the port of the iphone? I have an edge phone, not the 3g, and there is a bezel/lip that got in the way of my using a Radioshack plug. I had a similar idea, I wanted to make an ear-free cable with a mic attached to my seatbelt and the output of the phone go Aux-into my car head unit.

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  10. I inadvertently said I got the 4 conductor plug at Jameco - it was Mouser, and is listed correctly, with the part number in the blog.

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  12. Yay! thanks for the update Bent.

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  13. True. Just a tip though - I actually found it easier to use 5 conductors in the cable. Each jack needs a connection to ground, so I ran two ground wires from the plug. Otherwise you'll have to "Y" it somewhere, or daisy chain from one jack to the other.

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  14. This is a great tip. I happen to have a pair of my iPhone's original headphones around, and plan on using the cable from them, 4-C plug included. Now if only there were an app that would let you monitor while recording...

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  15. does this work with the first generation iPod touch?

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  16. "does this work with the first generation iPod touch?"

    The electronics should work, it's a question of if that style plug will fit. Most likely not. You may need to incorporate J.'s idea-

    "I happen to have a pair of my iPhone's original headphones around, and plan on using the cable from them, 4-C plug included."

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  17. I tried this. The iPod however expects an electret mic. So, there is some current flowing through the SM58. I think this may be harmful, so I tried several things with capacitors, resistors etc., although with no succes. Any thoughts about this?

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  18. I would be really surprised if a mic as robust as a 58 would be harmed with a little bit of charge. Thoughts?

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  19. Another thing I tried to do was trimming the input of the mic with a trim-pot. The iPod does not respond very well to this. It just won't see a microphone (or headset) and gives an error. This even happens when the pot is at 0 ohm, I think because there is still a resistance on the earth line. Can anyone think of a solution for this, for it might be very handy when trying to record from a loud sound source.

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  20. See original blog entry for capacitor update.

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  21. I've got a cheap dynamic mic to work as in input to my iPhone which is working great. I also wanted to be able to trim the volume but trim pot didn't work for me either.

    any good ideas about a passive volume control?

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  22. Has anyone tried this adapter from ShowMeCables? I'd rather not source the parts and build it if I could just buy it.

    http://www.showmecables.com/viewItem.asp?idProduct=8335

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  23. Thanks for this post, was using my multimeter and a tone generator I could switch left/right audio on to try and figure out what was what, but this helped more since I had not taken into consideration there being voltage on the mic. Luckily the mic im gonna use is a Electret mic, so don't need to go back to Radio Shack for anything else, just finish soldering the wires together.

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  24. frack, frell, drokle, smegin, dren. Got it working, then two of the wires broke cause I used a knife to strip the insulation since I couldn't find my wire strippers. Oh well, have to find them.

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  25. I made this cable to plug my guitar into my iPod, but there is an impedance mismatch and the iPod doesn't recognize the guitar. (Guitars are high impedance and the iPod is low impedance).

    Peterson makes this cable:
    http://www.petersontuners.com/index.cfm?category=150

    But it doesn't give you access to heaphones.

    Can anyone help me out with this?

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  26. This is fantastic,..and I think it is what I've been searching high and low for to enable me to use high quality mics for recording onto my ipod touch. Now is it possible to record and listen at the same time with this?

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  27. Yup, it splits into two sockets, one for the mic and one for headphones

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  28. Have I missed something? Nobody has pointed out the "obvious" simplification of just picking up and modding a TRRS to component cable like this one:

    TRRS to RCA

    Then all you have to do is buy two easily-acquired 3.5mm females and attach. You don't even need to bother with finding a mono female -- go ahead and just wire up the tip and the sleeve, it is electrically the same as a mono female jack, just a smaller but adequate conductive surface for the ground.

    I have assembled the parts for this but my soldering kit is in another country, I'll have to buy one and do the soldering before I can report on success.

    The capacitor is more or less unnecessary -- most microphones can deal with upwards of 48V (phantom power) being mistakenly applied, since this happens pretty regularly. Just don't hook up your precious ribbon mic to your iPhone!! :-D

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  29. hey I'm curious how Marc's cool idea turned out?! please explain your make up on this project and how it ended up working for you

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  30. I can't say I have ever wanted to plug in a professional recording decive in my ipod touch, but I have seen a store that sells professional hand grips for video recording for iphone 3gs lol

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  31. @Marc- Yes, I used that setup before I did this project. But, none of my connections were RCA (so I had to use adapters) and I wanted something short, not a long cable. But yes, you are correct - an A/V cable will work (although, then you still have the DC current to deal with)

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  32. Right, you can cut the A/V cable as short as you like since you are stripping the wire and still soldering on the 2 females.

    Likewise if you are concerned about the DC (which isn't going to hurt anything except a fragile ribbon, and helps you if you want to connect an electret), you can also put a cap in there somewhere when you are cutting it open.

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  33. Touche! :) And I thought about that at the time, however, I only have one of those a/v cables, and I use it for another device, and I got the parts for this breakout cable for cheaper than buying another a/v cable. (and I just wanted to build it from scratch). But, If someone had an extra one laying around, sure!

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  34. I wonder how can you make this cardioid mic working? I've tried on an iPhone 3Gs with a cheap external electret mic, it is working perfeclty but it's a no go with my Shure Beta 58A... Any trick?

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  35. Hi, two questions:

    Is it possible to connect dynamic mics with this cable?

    Is it possible to make a passive volume control for mic?

    With this passive volume control is possible to feed line level input?


    Thanks

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  36. I built my own using these instructions and this picture - http://www.mediacollege.com/audio/connection/xlr-jack-mono.html. I'm not an electronics guy by any means (unless something breaks and I figure I can use a soldering iron...) but I managed to cut off the red end of a 3xRCA to 1/8" 4 conductor video cable and connect the live/positive wire to #3 of an XLR jack, the shield to #2 and a short connector between 1 and 2. Amazingly, it works great with my iPhone 3GS.
    I didn't have any female jacks for the headphones - maybe next time.

    With a cardioid mic (SM57 copy) recording are dead quiet.

    Now I have a portable sampler/podcast-recorder!

    I'll post recording/pics if anyone's interested.

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  37. You can also find iPhone headset to pc adapters and vice versa at TheHeadsetBuddy.com.

    Bryan

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  38. @nicholaspaul please post your photos and did you use the capacitor or not to connect the SM57?

    (can you post small audio demo?)

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  39. @daigle have you actually used that cable? i've heard that Apple prevented the use of non-official cables with the last software update and a lot of people's cables stopped working...

    hence I started to think about buying the official Apple Composite AV cable. Only noone can confirm for me it ACTUALLY works as a line in for audio.

    i tried splicing out my Apple headphones and wiring a mono rca plug in place of the mic but i'm not that good at wiring and don't have a soldering iron handy so i got a lot of noise and mixed results, VERY low audio, when everyone says to expect high audio.

    so my other concern which noone here seems to have, so i must be wrong, was that there's no amplifier to boost the signal - i's strong enough to record? i'm trying to line in my korg keyboards rather than a mic.

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  40. nice work.

    I am doing something fun.

    I am using the iPhone app called FingerBeat (http://www.fingerbeat.com/).. I make some beats.. I also record some voice stuff over the top... well.. the way I record it is I run the audio from the phone out to a TASCAM DR-1 (http://www.tascam.com/products/dr-1.html).. I also use the FX button on the TASCAM to distort the audio some (makes my voice sound a it better)..

    So, I record it real nice on the TASCAM. But now I want to run it back in to my iPhone and use your cable.. because there isn't a good way to get it from the TASCAM into the phone.

    so what I did first is play it through some speakers into the iPhone's mic. and used the Voice Memos iphone tool to record it. And now I can send cool clips to people as MMS or whatever.

    (it would be nice if fingerbeat had an actual record button.. then this would all be real easy.)

    So, I think I will get this cable (http://www.showmecables.com/viewItem.asp?idProduct=8335) somebody recommended.. and see if it will give me a cleaner recording.

    and you guys have talked about controlling iphone mic-in volume.. I think my TASCAM can do that. anyway.. thanks. abe

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  44. okay. so I bought that cable. I plugged it in.. tried to record directly to my iPhone with it. It works and doesn't.
    I have the TASCAM.. so, if I use the TASCAM as a mic and record it on the iPhone.. that works. BUT, and this is weird to me, if I play some audio from the TASCAM to the iPhone, the iPhone won't record it. Also, if I run a plug from my Laptop headphone jack to the mic in (on the split cable) and that into the iPhone to record. nothing. nada. zilcho.. except, it still wants to record with the iPhone mic.. not through the cable. help.

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  45. Nice one! Any idea what's the frequency response of the iPhone? Does it do any kind of pre-filtering to the input? since it's mainly used for voice I would think that it would do some kind of bandpass filtering to separate speech, and then use a low sample-rate for all kinds of processing (recording etc.). Which kind of defeats the purpose of using a professional microphone... Just wondering though, I don't have an iphone but I'm thinking of getting one - on the other hand I'm sure it could capable of recording at 44.1kHz full bandwidth...

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  46. @lushr
    It does, and it seems to be working for other people as well. See the customer reviews for the PC headset to iPhone adapter on Amazon.com

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  47. I tried this but the iphone mic won't stop recording when I put in the external mic

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  48. @cele_82 My how time flies!!
    I made the XLR end of the cable and thought I'd get around to doing the headphone end soon. I didn't realise it would take me 6 months!!

    I posted pics here: http://www.flickr.com/photos/nburmandesign/sets/72157623955924967/

    Audio test is here:
    http://nburmandesign.tumblr.com/post/607482867/audio-test-of-iphone-breakout-cable (aiff converted to 192KBps mp3)

    I started with a 4 conductor mini jack to 3 x phone cable. I think it was meant for a video camera. The three wires were hooked up like this:

    RED (XLR)
    red wire (+) to #2
    ground (-) to #3
    jumper from #1 to #3 (that's the blue cable in the photo)

    WHITE (headphone jack)
    white wire (+) to tip (left hand connection)
    ground to sleeve

    YELLOW (also headphone jack)
    red wire (+) to ring (right hand connection)
    ground to sleeve

    I had to use a multitester to determine which was the ring and the tip in the 1/8" jack.

    Now to go find something to record!

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  49. @Nicholas

    Great! What type of mic did you use?

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  50. The mic is a Behringer XM2000S cardiod. Just your average SM57 wannabe shaped like a black 58.

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  52. Thank you so much, I was looking for this for a while and since I already had a cable from a camera will start tinkering soon. May I suggest you update the(why rough? it's great!) schematic with the potential location for the 10uF cap?
    Like is it in series with the input's center (hot) connection, right after the plug?
    That would be killer dude ;)
    Namaste

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  53. Yes a possible solution would be the Telephone wire" 4 conductor".
    I Said Possible!

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  54. Question. I essentially built the same cable using 1/4 stereo phone jacks, as noted here: http://www.ediy.co.nz/microphone-cable-for-ipod-touch-xidc55676.html . Everything works perfectly EXCEPT one thing.

    When I plug in a cheapo microphone (with 3.5mm connector (via 3.5mm to TRS adaptor) its works perfectly. But I plug in a mic with a mono TRS cable, it only work if I pull the plug out a bit -ie no tip connection. I assume this is because tip and ring and jumpered. Will the breakout cable still work wihout the jumper?? I assume its there for a reason.

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  55. I've just finished building a similar cable to work like an iRig for connecting a guitar to my iPhone 4. To get it to work properly you have to place a 1uF capacitor in series on the microphone signal (to remove the DC voltage), and a 1K resistor between the iphone side of the mic wire and ground. The resistor is necessary to make the iPhone 4 detect that an external microphone has been connected. I'll create a wiring diagram and post a link here soon.

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  56. Hi,

    Many thanks for your tutorial. I was wondering if you know how to mod an iPhone 4-pole headphone w/mic to be compatible with Nokia 4-pole headphone w/mic.

    One more question, if I remove the last black isolating ring from the iphone 3.5mm jack plug, will it become a normal 3-pole jack plug?

    Any advice will be highly appreciated!

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  57. Hey,

    So is the sleeve on the TRRS connector supposed to carry 2.7V?

    Cause my itouch doesn't pump out any DC voltage when I measured the sleeve....

    you can reach me at jinn@ualberta.ca


    Thanks

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  58. Just buy two easily-acquired 3.5mm females and attach them.
    Thomas & Betts products are good.

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  59. Check out this link, there is a commercial cable for those of us who don't want to mess around.
    Also a cable for a dedicated XLR mic input.
    http://www.kvconnection.com/product-p/km-iphone-2trs.htm
    http://www.kvconnection.com/product-p/km-iphone-43f35f.htm
    http://www.kvconnection.com/product-p/km-iphone-xtrs.htm

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  60. I'd like to use this as a DIY project to go hands-free in my car using my Samsung Galaxy S phone. I'm farily sure the phone uses a 4-pole 1/8 phono for audio out/mic in. Does anyone know of a good mic to use that would be sufficient to pick up my voice in a car? And should i go so far as to amplify th mic signal?

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  61. So, regardless of whether I can make or buy a cable that works, are you guys saying that there is no way you can monitor while recording?? That is what I want to achieve the most. I want to be able to buy FourTrack, lay down guitar tracks with AmpKit+, import a drum loop or something, then SING over it. I can bounce that stuff down all day long. But if I can't monitor the tracks I've already laid down while recording, what is the point??

    The bottom line is... is it possible to record vocals, guitar, whatever, while hearing what has already been recorded, via headphones. Essentially, basic multi-track recording like on a real fourtrack, with a 3G iPod running OS 4.1.

    I noticed that GuitarJack was on sale for $150, but it doesn't work with the iphone 4 or iPad! It's always something isn't it!! LOL!

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  62. thats cool... they look just like these ones i've been buying. http://www.magnusdeal.com/3-5mm-audio-aux-cable-splitter-male-to-two-2-femal-p/auxc-669.htm

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  63. I alredy built one and it is perfect but the only problem is i had no monitor while i'm recording. how can i solve this problem, can anyone help me? thanks.

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  64. First, thanks for publishing this; it took me quite a while to formulate my Google query properly so that it led me here.

    All I want to do is make an mike extension for my iPod4s. Your blog makes it easy by including the plug item number from Mouser.

    FYI the female inline jack for the other end of the wire (to mate with the mike I already have) item number is 161-6435-EX. I expect that connecting the appropriate terminals with a two-conductor wire will give me exactly what I need. Thanks so much for this blog entry!

    Chaz

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  65. Question: any ideas why this adapter is producing a distorted, lower bass, low-level headphone output and very low-leve mic in?

    The relevant symptoms are with both TRS and TRRS (iPhone headset w/mic) headphones, with or without a TRRS mic plugged in, in both an iPhone 5 and an original iPad.

    I haven't had a chance to continuity-test the wiring yet, but the voltage for the electret mic in iPhone headsets shouldn't be causing a problem for headphones going through this adapter, right?

    TIA

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  66. http://www.cablesonline.com/35mmsttmamic.html

    "This adapter" is the one in the link above. For some reason it didn't appear in my post!

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  67. i have

    4 pole 3.5mm to 3 rca female cable
    and two

    2x male rca to 3.5mm female

    how can i achieve the same ?

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  68. A blog give the good information on the ipod and iphone.
    Buy Used Cars

    ReplyDelete