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The Voices In My Head |
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Graham Slee
Admin Group Retired Joined: 11 Jan 2008 Location: South Yorkshire Status: Offline Points: 16298 |
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I'm interested too
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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps
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dillon
Senior Member Joined: 12 Oct 2011 Location: London Status: Offline Points: 214 |
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Soz been ultra busy again...
Well, it's fair to say Jon and Graham's theoretical ruminations on this effect are right on the ball. The can opener does exactly what my weird adapter does. Scientific method stipulates theory must be demonstrable to become a proper accepted Theory, and here we have a great example of that. The presentation is indeed pushed further out than normal. I am finding a slight emphasising of high frequencies, and left and right ear sounds are pushed out in the lateral plane away from the ears and closer to the soundstage/headstage. Imagine a dome going from your outer ears, with sounds wider and with more distance from the plane of the ears. There is no right or wrong. It's simply just two differing presentations of the music. And fun! Mix and match or choose one or the other. Don't really matter. Sit in the middle of a mix, or further back. As Jon said to me, variety is the spice of life. Oh and thank you Jon for the gift if the can opener! Sweet.
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Nottingham Analogue Hyperspace w Space Arm & Dynavector 10x5 HOMC/GSP Revelation M/John Sampson upgraded Meridian 508.24 CDP/Sony 777ES SACD/ProAc Response D18/GSP Solo ULDE/GSP cables and ICs
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Graham Slee
Admin Group Retired Joined: 11 Jan 2008 Location: South Yorkshire Status: Offline Points: 16298 |
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As resistor values will/should/probably differ with headphone impedance would it be an idea to have a two pole multiway switch with a number of resistor values, and possibly mount it and input and output stereo jack sockets in an (upturned) plastic project box?
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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8958 |
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Thank you for your quick responses and that's a good idea Graham. For the protoype I just used a 50 ohm preset pot thinking it would work for 16 - 50 ohm headphones and allow the effect to be varied. I didn't measure the setting before sending it off but it looked under a quarter so 12 ohms or so.
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8958 |
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I wish I had taken a photo of the simple but effective rig I sent to Dil. He may oblige with a quick upload, please.
That was minimum parts for maximum benefit - one 1/4 jack socket and one 1/4 jack plug with the L and R tags soldered together, and a variable resistor between their ground tags. I'll photograph the Maplin stereo jack Y-adaptor and its internal parts at the weekend, and show how the can opener can be built. |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8958 |
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I was going to build another unit this weekend like the one I sent to Dil but it's harder to get the parts quickly. Here is a drawing of what I built using a 50 ohm present pot:
*The open plastic jack sockets usually have two sets of tags, one side which I used makes contact with the plug when it is inserted, whilst its contact with the other side is disconnected. The effect of the reistance in the shared earth or return path is to cancel out some of the central (or 'middle') signal that appears on both left and right. This lowers the relative volume of centrally positioned sounds in the mix, which will include lead vocals and some of the bass usually panned there. In doing so it raises the level of the sounds on the left and right of the mix (the 'side' signal). Some of the signal from the left channel will return via the right channel but out of phase, and vice-versa, giving the widening effect as well as changing the balance of middle and side. This makes the stereo image wider hence the 'voices outside my head' effect. I think you could regain some of the low bass with an inductor in parallel with the resistor but it would shift the phase and so have worse side effects I imagine! You can vary from no widening or standard sound with the pot at zero or fully anticlockwise on my drawing to a much wider sound. The latter will be close to the sound Dil experienced when his extension lead had a partial connection on the ground or return signal. The extreme version would be having no ground connection so the signal is only the 'side' signal heard centrally in mono. With the pot it's a bit less extreme but does make an audible difference to music in stereo. With my LCD-2's I found my preference was for the pot at about one quarter which is probably around 10 ohms, give or take. As the LCD-2's are fairly flat impedance of about 50 ohms, that may help to estimate a starting position for different headphones. Have fun! Edited by Fatmangolf - 28 Apr 2018 at 12:13pm |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8958 |
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My use of the stereo splitter adaptor was the next stage to make something more compact. Based on my experience with the pot setting, I decided to try standard resistors of 8 ohms and 16 ohms. Low wattage resistors will probably be fine at the volume I listen to my headphones. You can do the same quick calcs I did using V=I/R and P=Vsquared/R.
The adaptor would give two sockets that offer widening options slightly below and slightly about the 10-12 ohms on the pot, the third option of standard sound being achieved by removing the adaptor of course. A quick hookup with some crocodile leads and a pair of 8R2 resistors suggests I am in the right area. It would be interesting to hear how the sound of headphones with impedances that vary with frequency are effected by the can-opener. |
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Jon
Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
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