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Making Your Headphones Wireless?

Posted by Cliff on from the wireless-headphone-kits dept.

Chuck Chunder asks: "I've recently been looking at getting some wireless headphones of the RF rather than infra-red variety. After looking around for a bit it struck me that I don't actually want a whole new set of headphones. I already have a nice pair of headphones as well as earphones. What I really want is an RF transmitter and a small clip on receiver that I can plug my existing headphones/earphones into. The problem is, I can't find anyone selling what I am describing, even geeky places don't quite have what I'm looking for. Does anyone know/have experience of such a product?"

"I see several advantages to this:

  • Adaptability: I can then use earphones/headphones as appropriate for the activity, or possibly use it as an RF link between hardware in different rooms
  • Replacability: If I damage the headphones I only have to replace them, not the whole headphone/receiver unit; this bit will hopefully lead to...
  • Lower costs
Has anyone seen something like this, before?"

26 of 67 comments (clear)

  1. This won't work by PhysicsGenius · · Score: 2, Informative

    RF devices suffer from a great deal of interference in the high-end band from sources such as sun spots, satellite traffic and meteor showers. Headphones, being small amplifiers, will only make this static louder. I suggest you buy a longer cord.

    1. Re:This won't work by shepd · · Score: 2

      Either make the headphones digital, eliminating all of the static, or use headphones like mine, which don't use RF at all and instead modulate the sound over IR.

      My experience with wireless headphones has been quite good, and there's absolutely no reason why decent quality sound can't be transmitted a short distance. Just look at 802.11b, for example. More than enough bandwidth for full CD-Audio quality. If it comes down to it, why not integrate this into your home theater?

      --
      If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
    2. Re:This won't work by walt-sjc · · Score: 2

      Of course it will work. I've done this before. Get yourself one of those cheap FM transmitters that transmits in the normal 88-107Mhz band (it's low power). I think radioshack even carries them (or they used to...) Searching google works too. Then get a cheap AM/FM "walkman". I have a freebee from some tradeshow that's only about 1/2" thick, 1-1/2" square, with a belt clip. Works great.

      Sun spots... Good grief. They guy is going to be a few feet from the transmitter. All sources of interference except from his computer will be a non-issue.

  2. You mwan you want this? by hackwrench · · Score: 5, Informative

    Here?

    1. Re:You mwan you want this? by inburito · · Score: 2

      Having used this quite a bit I can say that even though it is a pretty good deal it is still far from perfect. This Jensen unit works fairly well but as it is analog it is suspect to the limitations of analog technology, ie. you will hear static moving around the house and yard. If they had made this digital it would be near perfect.

      One of my goals was to provide a wireless link for three persons to listen simultaneously up to a distance of about 100-150feet and this did work quite well. Having people be able to use their own headphones was big plus and actually a requirement.

      It did take me quite a few days to find this baby so I would not flame the original poster too much. I just wish that people would just use usenet for things it is best suited for and bother slashdot with something more geeky..(ie. digital spread spectrum version of this would be geeky enough..)

  3. Have you considered a Walkman for receiving? by Papineau · · Score: 3, Interesting

    Building a radio emitter is not very difficult (I remember having an electronic kit when I was young with 60+ different circuits you could build, and one of them was a radio emitter). Ideally you'd choose it not to interfere with your local channels, or some neighbours could become upset if your power is too high.

    Then, on the receiving end, a small walkman is all you need. Plug your headphones or earphones, and there you go!

    Of course, the quality of the transmission will vary depending on the quality of the hardware and which frequency you choose (near or far from some other channel).

    1. Re:Have you considered a Walkman for receiving? by cookd · · Score: 2, Informative

      Or you buy the equivalent at Walmart for $10. Popular for using CD players in cars.

      But I think this guy wants a little bit higher quality and longer range...

      --
      Time flies like an arrow. Fruit flies like a banana.
  4. Here is anouther solution for you. by Neck_of_the_Woods · · Score: 3, Insightful

    Turns speak output into FM channel

    At which time you just tune it into your walkman, or radio headphones. Simple solution for mp3 players to your car stereo as well.

    --
    Neck_of_the_Woods
    #/usr/local/surf/glassy/overhead
    1. Re:Here is anouther solution for you. by rcw-home · · Score: 2
      An FM tranmission is at an effective quality of 22kHz

      Not necessarily - the FM broadcast band layout gives each channel 200kHz of bandwidth (which is why all FM broadcast stations have center frequencies ending in an odd digit). Nyquist's theorem says you only need 2x bandwidth to represent a given frequency.

      If you're operating under Part 15, then how much AF spectrum you represent with this is up to you. The more you use, the better the signal/noise ratio you need (Shannon's law), however representing 1kHz of AF with 4.5kHz of RF is already overkill.

    2. Re:Here is anouther solution for you. by Bishop · · Score: 2

      the L-R channel is broadcast on a 34 KHz subcarrier.

      A slight correction: It is 38kHz, see second box down. But who is counting. This makes sense as it is pretty easy to frequency double the 19kHz pilot and demodulate the L-R subband.

      The site also claims that the channels are only 15kHz. Elsewhere I have seen claims of 17, 18, and even 19 kHz.

    3. Re:Here is anouther solution for you. by Bishop · · Score: 2

      You are comparing analog to digital bandwidth. Two different things. As per Nyquist's theorem 44ksamples/sec digital can acurately reproduce a 22kHz analog signal and no more. So in theory a 44kHz mp3 is about equivalent to a 22kHz analog signal. In reality you can't get quite that good, but it dosen't matter as few can hear much past 18kHz anyway.

      As discussed elsewhere an FM transmission has an audio bandwidth of about 17-18kHz, so yes in theory a 44kHz mp3 will be better. Although mp3's sound crappy so you probably won't notice. Nor can most cheap headphones acurately reproduce higher frequencies. So really you have bigger things to worry about then the few kHz of bandwidth you might lose by broadcasting on FM. Things such as the weak transmit power.

    4. Re:Here is anouther solution for you. by pete-classic · · Score: 2
      So in theory a 44kHz mp3 is about equivalent to a 22kHz analog signal. In reality you can't get quite that good, but it dosen't matter as few can hear much past 18kHz anyway.


      You have made a jump from sample rates to sound freqencies here that isn't valid. I can't hear a tone above 20kHz, but I can certanly tell the difference between a track sampled at 22kHz vs. on sampled at 44kHz.

      -Peter
    5. Re:Here is anouther solution for you. by Bishop · · Score: 2

      There is nothing invalid about my statement. A 44kHz mp3 is an audio signal sampled at 44ksamples/sec. As per Nyquist such an mp3 can (in theory) encode a 22kHz audio signal. My statement regarding 18kHz is refering to 18kHz audio. The dual use of kHz, audio/analog vs digital, is rather confusing.

      Naturally you can hear the difference between a 22kHz digital signal and a 44kHz digital signal. You are looking at analog bandwidths of 11kHz and 22kHz respectively.

  5. Anouther solution for you. by Neck_of_the_Woods · · Score: 2, Redundant

    Link to speak out to FM

    This little jewel lets you plug it into your mp3 player and then it tranmits to a FM channel. You could use it in this case to transmit your computer sound out to a small fm headphone set. Or in my case I plug it into my mp3 player and then catch the FM station on my car stereo. Perfect little fix without spending a ton of new money. The kicker at work is you could let everyone with 30 feet of you tune into your custom FM station playing your mp3's.

    --
    Neck_of_the_Woods
    #/usr/local/surf/glassy/overhead
  6. cheap wireless unit for guitar by incast · · Score: 2, Informative

    you could try a very cheap guitar wireless unit. It'd be quite the hack, with a lot of 1/4"-1/8" adapters (and vice versa), but it'd work. My cheap wireless (a Nady Wireless One) has a range of about 1500 feet via a 235-ish mHz transmitter/receiver combo.

    There's one here on eBay right now for $25.

  7. FM Broadcast transmitter by smurd · · Score: 2, Informative
    I went through a bunch of "propriatary" headphones for watching tv. After problems with batteries, interference and the expense (if you step on the headphone, you need to buy a new transmitter). I decided to go with a real FM Broadcast band transmitter. I got me a Ramsey
    FM 25 kit (it has to be a kit, FCC rules)
    and have been loving life since. Some of the bennifits include:
    • You can use any headphones that receive FM
    • I can use a little pocket radio around the yard playing CNN
    • Much more development effort and cost reduction goes into a mass market item than the big clunky "wireless" headphones
    • It's "open source" (grin)

    It took about 4 hours to build the kit and was not difficult (all components are through hole).
    At $130, it''s not cheap initally, but you will wind up saving money in the long run.
  8. Re:Advent Headphones. by Neck_of_the_Woods · · Score: 2

    Little pin up anger buddy? I was just giving out a little information for the people that were also looking for headphones. You will also notice I posted a solution to his problem. Try and anger management class, or rub one out. You need a release.

    --
    Neck_of_the_Woods
    #/usr/local/surf/glassy/overhead
  9. This is easy by trailerparkcassanova · · Score: 2, Funny

    Put on your headphones without plugging them in and turn your speakers up really loud.

  10. Steps by smoondog · · Score: 2

    1. Buy a pair of headphones
    2. Buy a laptop
    3. Build a 802.11b wireless net for your apartment/home/domicile
    4. Share/nfs/serve your mp3's from your desktop.
    5. Retrieve/mount/client your desktop's mp3s from your notebook.
    6. Enjoy music

  11. Taking it to ridiculous levels.... by mshomphe · · Score: 2

    I had a great idea: Wireless earpieces for cellphones. That wire is a pain to deal with. Of course, it almost feels like a similar idea to a remote controlled remote.

    Somone's going to make a pile of cash off this idea, aren't they?

    --
    She sat at the window watching the evening invade the avenue.
    1. Re:Taking it to ridiculous levels.... by Matthew+Weigel · · Score: 2

      They're called Bluetooth headsets, and yes, they cost a ridiculous amount (in the range of $200).

      --
      --Matthew
    2. Re:Taking it to ridiculous levels.... by robin · · Score: 2

      A wireless earpiece for cellphones, eh? What a good idea!

      --
      W.A.S.T.E.
  12. Pretty much, yeah. by Chuck+Chunder · · Score: 2

    That looks pretty good. Other peoples comments on digital v analog for reducing static and wireless phones (which I have, as well as living in an apartment building so there could be others near by).

    Looks like I've got a bit more research to do before I stump up the cash but thanks for the pointer.

    --
    Boffoonery - downloadable Comedy Benefit for Bletchley Park
  13. Re:Wireless Earbuds by technos · · Score: 2

    A bunch of companies make full AM/FM radios in an earbud. Had one a few years ago, cost me a whopping $14, with digital tuning and a L/R/Mono switch. Set one to right, one to left, and use one of those $40 AAA powered FM transmitters.

    --
    .sig: Now legally binding!
  14. Regurgitating false information by pauldy · · Score: 2, Informative

    Ok I've seen way to many of these posts dogging anything less that 900MHz or 2.4GHz. First to clarify why we like higher frequencies better. High Q circuits or the relationship between the cuttoff and ideal resonance gives us less interference with larger bandwidths at higher frequencies with less power lost. This is great for the ever shrinking world of electronics were we want less power loss cause we like batteries to last longer, smaller wavelengths shorter antennas/permeates through more structures easier... This however does not mean that circuits with a lower Q value like those you would find with the same bandwidth at a lower frequency lack any ability to reproduce the audible spectrum. Granted it does require more electronics to filter out things like harmonics and possible outside interference but that doesn't mean it will sound any worse that a 2.4GHz products. It is simply cheaper to make consumer goods like this and assume it is of a quality that is acceptable enough to be sold at a particular price point.

    What I would recommend is you find a product that you can test out before purchasing or has a liberal enough return policy that you could use the product and decide if it works for you because a poorly designed 2.4GH product could sound far worse that a well designed 87-108MH product.

    To examine what I'm talking about here further just search for resonant circuits on google.

  15. This is the way to go! by xtal · · Score: 2

    This is definately the way to go. Alternatively, you might get away with some low power VHF ham gear if there's nobody in the area to hunt you down and yell at you - but at 30mW, your broadcast range won't be very high either. The kit is going to be much cheaper than that anyhow, unless you have the gear already. You WILL lose some fidelity over the wired headphones though, don't kid yourself. Most people will never notice the difference.

    Mildly off topic, don't ever read anything on how to detect errors in compression. I used to work with MPEG codecs and I can't watch most of the movies on the net.. I can imagine what learning to detect mp3 artifacts does :).

    The only thing that would be better is if you designed or bought a small digital transmitter and decoder with a 16bit x 44.1kHz bandwidth. These units might exist out there if you look, but every single one of the stand-alone FM units (aside from quality kit like the Ramsey unit) blow chunks because of frequency drift or intermittant static. The other problem is batteries go dead, I listen to music all day when I'm at work.

    FWIW my solution at work is to stream to my notebook and then listen off it.

    --
    ..don't panic