Joppe Peelen
Active Member
Posting planar magnetic contraptions here is always scary... since well, people here know way more about measuring then i do, and they will NOT ever beat a woofer in a box... (to a extend 
then again... there are people liking them, like me, maybe because its something i can make from scratch and not buy some components.
Anyhow, i made a contraption (current size including frame 60x40 cm) , based on an idea i had for some time. instead of using metal with magnets on one side... (single ended , driven... pretty non linear) or metal and magnets on both sides.(PP push pulll, although it should be actually PUSH PUSH...) and the idea i had. no metal, but suspend the magnets in the middle and use 2 membranes. so thats what i did. downside... resonance shoots up, because its not having the same air amount damping it. secondly but for me most interesting is, one foil moves away from the magnets at excursion.. while the other moves towards it. in theory the field should kind of be equal at all times if you would look at the whole thing as one driver, now this is never 100% true but at least the idea is somwhat true, in this video where i play a tune i also measure the LRS compared to the contraption i made. now for all single ended planars lows 2e order is by far the biggest distortion (usually because of non linear motor design) and as you can see this panel with 6 times the x max, had less 2e order. anyhow. i dont want to write it all out.
here is a video with tune recorded with binaural mics on the cough where there is still to much low end , i also added some medium range measurements from a LRS vs this panel (70 cm dB not calibrated. but i did not want to push the LRS more) just to see what happens in the distortion.
In video 1 i include a measurement of the first prototype of 1 membrane VS 2. where you can see based on 2e order distortion the motor did get more linear. especially for a single ended magnet structure (i still use the same amount of magnets a single ended speaker would use)
if anyone has a good idea of damping the Main resonance? adding some felt in between the foils is instantly to much damping, i even tried a small piece of silk screen with low hole count.. it damps to much and i also think it hurts the way they work in tandem/distortion, you will damp a part of the foil but i got the feeling it moves less regular over its surface when doing so
Video 1 some building and first try of the idea (this one had to high resonance)
Video 6 Done building a version 3 and played 2 tunes and show the measurement LRS vs one of these small panels. i dont have any other commercial planar magnetic here to compare so thats what it is.
Video 3 i try to explain my idea...
then again... there are people liking them, like me, maybe because its something i can make from scratch and not buy some components.Anyhow, i made a contraption (current size including frame 60x40 cm) , based on an idea i had for some time. instead of using metal with magnets on one side... (single ended , driven... pretty non linear) or metal and magnets on both sides.(PP push pulll, although it should be actually PUSH PUSH...) and the idea i had. no metal, but suspend the magnets in the middle and use 2 membranes. so thats what i did. downside... resonance shoots up, because its not having the same air amount damping it. secondly but for me most interesting is, one foil moves away from the magnets at excursion.. while the other moves towards it. in theory the field should kind of be equal at all times if you would look at the whole thing as one driver, now this is never 100% true
but at least the idea is somwhat true, in this video where i play a tune i also measure the LRS compared to the contraption i made. now for all single ended planars lows 2e order is by far the biggest distortion (usually because of non linear motor design) and as you can see this panel with 6 times the x max, had less 2e order. anyhow. i dont want to write it all out.here is a video with tune recorded with binaural mics on the cough where there is still to much low end , i also added some medium range measurements from a LRS vs this panel (70 cm dB not calibrated. but i did not want to push the LRS more) just to see what happens in the distortion.
In video 1 i include a measurement of the first prototype of 1 membrane VS 2. where you can see based on 2e order distortion the motor did get more linear. especially for a single ended magnet structure (i still use the same amount of magnets a single ended speaker would use)
if anyone has a good idea of damping the Main resonance? adding some felt in between the foils is instantly to much damping, i even tried a small piece of silk screen with low hole count.. it damps to much and i also think it hurts the way they work in tandem/distortion, you will damp a part of the foil but i got the feeling it moves less regular over its surface when doing so
Video 1 some building and first try of the idea (this one had to high resonance)
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