Several years ago Speaker Builder magazine ran an article detailing a DIY planar magnetic build. It was a two-way design using a 10" woofer for frequencies below about 400Hz. Anyone recall the article or have access to it?
The articles were published in 1995/1996. Attached is a pic of the 1995 cover.
I used to have a copy, but couldn't locate it last time I looked for it.
D. Patten, "A Push-Pull Planar Speaker Quest, Part 1", Speaker Builder, No. 8, (1995).
D. Patten, "A Push-Pull Planar Speaker Quest, Part 2", Speaker Builder, No. 4, (1996).
I believe these were the forerunner to the PS40.
Alternate-Audio
I used to have a copy, but couldn't locate it last time I looked for it.
D. Patten, "A Push-Pull Planar Speaker Quest, Part 1", Speaker Builder, No. 8, (1995).
D. Patten, "A Push-Pull Planar Speaker Quest, Part 2", Speaker Builder, No. 4, (1996).
I believe these were the forerunner to the PS40.
Alternate-Audio
Attachments
Bolserst thanks for the info.
I built a pair but haven't used them for a while because the room's not big enough. I was thinking about reviving them anyway.
I built a pair but haven't used them for a while because the room's not big enough. I was thinking about reviving them anyway.
If you're still looking I could scan a copy for you. I don't know if there is a copyright problem with attaching it, but it is ~ 20 years old, I doubt the successor to Speaker Builder would care. Let me know. Scott
Hello Scott - I would like to get a copy , please send it attached to an email to speakertweaker2001@yahoo.com , thanks!
Bye, Marveloudio
Bye, Marveloudio
Yes, I would like I copy as well!!
You can PM me your link when you are ready or you can send it to me via email as well at, geraldfryjr@comcast.net
Thanks!!
jer 🙂
You can PM me your link when you are ready or you can send it to me via email as well at, geraldfryjr@comcast.net
Thanks!!
jer 🙂
I scanned the two articles and emailed them to the 2 DIY'ers above. The file sizes are a bit large to post. Anyone else? Scott
Ok, I sent copies again by email. It's a big email (6MB total), so let me know if anyone who wanted it didn't receive it. If I get much more demand, I might ask audioxpress for permission to post it on my website - not sure if they still sell those old issues.
I like the Patten articles, especially because he points out some problems and suggests solutions in the 2nd one. Having tried a couple times (with both planar magnetic & ESL), these planar speakers are difficult to get right. Mine had unwanted resonances, and I could see it would be a big effort. Even Magneplanar and Martin Logan seem to be fighting this.
Are there any articles anyone has found particularly helpful? Scott
I like the Patten articles, especially because he points out some problems and suggests solutions in the 2nd one. Having tried a couple times (with both planar magnetic & ESL), these planar speakers are difficult to get right. Mine had unwanted resonances, and I could see it would be a big effort. Even Magneplanar and Martin Logan seem to be fighting this.
Are there any articles anyone has found particularly helpful? Scott
Much obliged, Scott!
There are several issues addressed that still pose problems, I think vibrations due to resonances will be the biggest challenge for me anyway.
I mean, anyone can glue some magnets...
Interesting with the open cell foam that "rectifies" the air flow.
I'll also go for using (magnetic) wire instead of foil; it is much easier to get the shape correct as the wire can be laid in layers without any isolating tape in between. But foil has its benefits as the current density can be varied if the field is stronger/weaker in some area.
I am not sure though that the membrane needs to be light weighted if the intended frequency range is in the bass region. I suspect that fs still relies on mms and cms. So a heavy membrane with a flexible surround should the goal for that.
There are several issues addressed that still pose problems, I think vibrations due to resonances will be the biggest challenge for me anyway.
I mean, anyone can glue some magnets...
Interesting with the open cell foam that "rectifies" the air flow.
I'll also go for using (magnetic) wire instead of foil; it is much easier to get the shape correct as the wire can be laid in layers without any isolating tape in between. But foil has its benefits as the current density can be varied if the field is stronger/weaker in some area.
I am not sure though that the membrane needs to be light weighted if the intended frequency range is in the bass region. I suspect that fs still relies on mms and cms. So a heavy membrane with a flexible surround should the goal for that.
got the scans , again - thanks!
nice SB article , lots of info ... btw I have 6 of the Strathearn magnetostatic drivers in good condition in stock but without transformers - I drove 2 others slightly modificated using a 1.5 ohm resistor in series resulting in a load of 2ohm , no problem for my old Kenwood KA907 , never had a speaker protection relay event .
Very soft and "springy" cotton wool face makeup removing pads in 8mm thickness , cut to rectangle pieces and placed under/over the foil zones at the sides beneath the conductor made the freq response totally flat , no need for any EQ - but it is very difficult to implement , I would not do it again .
But by installing new new foils it would be an option ...
The original polyether foam stripes hardens with time and get brittle , not a good solution for long term damping consistency .
Older Strathearn incarnations had fine yellowish glass wool damping on the sides - works much better than cheap foam .
Foil was 6um mylar and 9um aluminium foil on one side , bonded together with polyurethane glue which seem to shrink over time and warps the surface ... so choosing some better suited glue is recommended as the warps are causing easy to hear buzzing noises even at low playback level with pink noise/terz bandwith at some freqs around 800 - 2000Hz . With music this is masked in most cases by our hearing mechanism which concentrates of the most relevant tones of a spectrum from a complex signal .
hope this helps , bye - Uncle Marv
nice SB article , lots of info ... btw I have 6 of the Strathearn magnetostatic drivers in good condition in stock but without transformers - I drove 2 others slightly modificated using a 1.5 ohm resistor in series resulting in a load of 2ohm , no problem for my old Kenwood KA907 , never had a speaker protection relay event .
Very soft and "springy" cotton wool face makeup removing pads in 8mm thickness , cut to rectangle pieces and placed under/over the foil zones at the sides beneath the conductor made the freq response totally flat , no need for any EQ - but it is very difficult to implement , I would not do it again .
But by installing new new foils it would be an option ...
The original polyether foam stripes hardens with time and get brittle , not a good solution for long term damping consistency .
Older Strathearn incarnations had fine yellowish glass wool damping on the sides - works much better than cheap foam .
Foil was 6um mylar and 9um aluminium foil on one side , bonded together with polyurethane glue which seem to shrink over time and warps the surface ... so choosing some better suited glue is recommended as the warps are causing easy to hear buzzing noises even at low playback level with pink noise/terz bandwith at some freqs around 800 - 2000Hz . With music this is masked in most cases by our hearing mechanism which concentrates of the most relevant tones of a spectrum from a complex signal .
hope this helps , bye - Uncle Marv
With Elektor's permission, I posted the two articles online for anyone who didn't get them yet.
Downloads – Tavish Design
Let me know if the link doesn't work, etc. Scott
Downloads – Tavish Design
Let me know if the link doesn't work, etc. Scott
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