cttm Posted September 14, 2011 Share Posted September 14, 2011 As a longtime Klipsch speaker owner/lover I have finally purchased my first set of Image S4 earphones. I love the sound but have only one problem - only one of my ears work so I only hear one channel. I've tried adjusting speaker balance to increase volume in the bad ear relative to the good, hoping to gain some benefit through bone conduction. This hasn't worked well enough to hear more of the unheard channel. I've thought of making a short adapter plug/jack wired so the separate LH/RH leads from an 1/8" stereo plug connect to both LH and RH terminals of an 1/8" stereo jack in an effort to combine both channels. Not being an electrical engineer I don't know if this will work without damaging the earbud drivers, or if any resistors need to be included. Does anyone have any recommendations? Will my idea work? Can you please provide a wiring schematic if resistors need to be included in the adaptor. Thanks for your help! Quote Link to comment Share on other sites More sharing options...
WMcD Posted September 14, 2011 Share Posted September 14, 2011 Welcome to the forum. Let's hope that some other people confirm what I write. I'm not familiar with bone conduction hearing aids but it seems like you might be in view of your situation. It may be that you are using one in your weak ear. Just how loud that gets I wouldn't know. From your description you've tried finding a balance control on whatever device you are using to drive the S4. It is not clear whether that project failed for lack of getting access to a control (if it exists on the audio controls for an I-Pod or Android) or whether bone conduction does not work if you can -- say -- drive up the output to the weak ear by 20 dB or something. But back to the problem. It seems that you would like L+R audio delivered to your good ear. My first advice would be to hunt around all technical resources on the Internet to see whether your device can be switch to mono output. That will be specific to your device so I'll have to leave that up to you. Excuse if this is obvious. The second goes closer to your question. It is whether the Left and Right outputs of a given device can be connected together to give a summed output. In theory that depends on the output circuits. But, overall, it could lead to the distruction of the output driver transistor. Each amp is expecting to drive an 18 ohm load of an S4 (value per the cut sheet or the S4). This resistive load is just passive. But consider what happens if you tie the two outputs together. Each output is seeing the full voltage of the other output. And in "stereo" situation, the voltages are different. In a worse case condition one amp might output + one volt and the other output - one volt. If the outputs are shorted together to feed an earphone, each output "sees" zero impedance and a very great current draw. The solution to this is a resistive mixer, in theory. Put a 40 ohm resistor (a 1/4 watt should do) in series with each output and then then tie the other end of the two to the single headphone input. It should sum the outputs without presenting a difficult load to the amps. On the other hand, it is lossy. You'll be losing 6 dB or so. Also, the frequency response may suffer. My best thoughts. WMcD Quote Link to comment Share on other sites More sharing options...
cttm Posted September 15, 2011 Author Share Posted September 15, 2011 Thanks for your advice. You've pretty much confirmed what I thought would happen - constructive and destructive interference of the waveforms at the extremes and a muddled mess in the middle. As a test I'll try out the resister option and let you know the result. I did find one product online where two drivers are installed into one earbud which would get around this problem. However they're about $450 for one device with custom molded to an individual ear canal (like a hearing aid which I do not need.) Perhaps Klipsch could develop a similar product for those of us who like good sound despite being "hearing impaired". I'm sure I'm not the only one with this condition. Regards, cttm Quote Link to comment Share on other sites More sharing options...
BLSamuel Posted September 15, 2011 Share Posted September 15, 2011 If increasing the volume a lot relative to your good ear might work you might try the PA2V2 headphone amplifier which has internal gain controls for each channel found at www.electric-avenues.com It sounds like summing the output into one might work best for your situation but thought I'd share this just in case. It is pretty inexpensive I think $60 or less. Good luck Quote Link to comment Share on other sites More sharing options...
bwbike Posted September 16, 2011 Share Posted September 16, 2011 Can you set your music device to play in mono mode? My iPod has a mono setting. That way both earbuds would have both left & right channels and you should hear all the music in either ear piece. Quote Link to comment Share on other sites More sharing options...
cttm Posted September 16, 2011 Author Share Posted September 16, 2011 Thanks for the info. I'll check into it. Quote Link to comment Share on other sites More sharing options...
cttm Posted September 16, 2011 Author Share Posted September 16, 2011 My laptop (Dell Precision M4400 workstation) does have a mono mode for it's speakers but no mono setting for earphones. I've tried the mono setting anyway but can not notice any difference from the stereo mode. Thanks for asking, though. Quote Link to comment Share on other sites More sharing options...
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