Pundit
Post by garym on Jun 13, 2019 13:13:19 GMT 12
Ask Simon Brown. He has a friend with some. I think you need to be able to use the room corners to get the bass performance. The Pensil can sit out into the room.
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Pundit
Post by garym on Jun 14, 2019 10:47:58 GMT 12
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Pundit
Post by garym on Jun 14, 2019 10:49:47 GMT 12
Ahh... Only the MS series of drivers are spiderless.
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Post by colinf on Jun 14, 2019 19:18:49 GMT 12
Kjfaudio looks interesting, nice link. They’re ‘up north’ in the UK. Now I see where you’re learning about the Pensil and Frugelhorn kits. MS..Mono Suspension. Also a patent-pending negative camber cone to improve dispersion on the new-tech Alpair MS drivers. I see the Markaudio drivers are also used in their new range of built speakers called Markaudio Sota.
AMR-iFi R&D
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Pundit
Post by garym on Jun 15, 2019 18:23:54 GMT 12
Info on Pensil originally came via Diyaudio, and likewise Frugalhorns. The guys who are behind the Frugalhorn are on there. They are big Mark Audio fans. A friend in Belgium markets a loudspeaker using Mark Audio drivers. Pearl Acoustics.
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Post by Owen Y on Jun 15, 2019 20:29:42 GMT 12
Another (TQWP) design from diyaudio.com is the BIB (Bigger Is Better) speaker design, if you want small footprint & can tolerate a tall (but thin) box. Relies on ceiling to load the LF output.
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Post by colinf on Jun 15, 2019 21:49:02 GMT 12
Like the concept behind the BIB, Owen, with the ceiling location of the TL end. Why 2 drivers? I saw the Pearl Acoustics version of the Pensil, very very nice. But my budget is currently at DIY levels I’m afraid! I think I’m getting more inspired to go and build a Pensil 11 kit with the new Alpair 11 MS driver. The cnc-cut birch ply enclosure is appealing. I also like how you can control how much bass output there is with the amount of dampening material inside.
AMR-iFi R&D
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Post by Owen Y on Jun 16, 2019 17:53:29 GMT 12
No Idea why 2 drivers... more cone area perhaps. Also, the driver placement should be at 1/3-point in the 'pipe', according to Voigt's original concept...
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Post by colinf on Jun 16, 2019 21:46:40 GMT 12
I see why the TL is tapered now, to reduce the Q of the bass resonance and have a flatter response. Also why there needs to be a bit of damping as the midrange coming off the rear of the driver needs not to bounce around inside the closed end of the enclosure and taint what should be bass only out of the open end. There’s just one little issue I have with bass augmentation by a ported box, or using a transmission line; that the bass wave from the port or opening is delayed by 1 cycle before the resonance gets going and augments the front wave from the driver, and so transient response may be diminished, unlike open baffle or sealed systems. Can that be the case, and if so, could it be a problem in reality?
AMR-iFi R&D
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Pundit
Post by garym on Jun 17, 2019 18:31:43 GMT 12
The authority on Transmission lines and their ilk these days is Martin King of the Quarter Wave site. www.quarter-wave.com Associated with that is a Facebook group that he hosts and which discusses these and also open baffle designs. He had developed some very powerful MathCad modelling worksheets that enable the detailed design of Transmission line variants and also open baffle designs. Unfortunately due to commercial pillaging of these they are no longer availble. His advice and invaluable comment still is though. The Mark Audio enclosure designs have had a lot of input from Scott Lindgren of Woden design. You can google Scott for more perspective on his contributions. www.wodendesign.com
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Post by colinf on Jun 17, 2019 19:26:01 GMT 12
Thanks for the links, lots of reading to be getting on with!
AMR-iFi R&D
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Pundit
Post by garym on Jun 17, 2019 19:33:26 GMT 12
Scott Lindgren presenting...
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Post by colinf on Jun 18, 2019 4:09:50 GMT 12
I enjoyed that 99.99999 percent! NWAS...North West Audio Show near Manchester. This year it’s on at the end of June. Also just watched Mark Fenlon talking about his new Alpair 11 MS spiderless driver, clever design. Although I wonder how the voice coil stays aligned in the gap over the years. Won’t the surround, which is the only suspension, sag over time, perhaps necessitating the driver to be rotated in the cabinet regularly? I’m sure he’s worked it out though.
AMR-iFi R&D
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Pundit
Post by garym on Jun 18, 2019 11:26:02 GMT 12
Mark is a clever guy... I'm sure he has thought it well through. I hosted him for a day in Wellington back in about 2011. At that time he was considering moving to NZ to set up his business here. Unfortunately health issues intervened and his plans changed. A nice guy. When we were driving to the city from the airport he pointed at the water in Evans Bay. It was pretty flat, but not calm, with just a uniform ripple on the surface. He said "thats what the cone on our drivers looks like when reproducing" Its this that creates a full range driver. Controlled break up if you like, not a pistonic action. This is achieved by significant innovation in the cone technology.
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Post by colinf on Jun 18, 2019 21:37:08 GMT 12
Yes, I wanted to move to Wellington too, but the family had other plans. It’s a great little city, apart from the potential for a big wobble. Interesting to compare cone behaviour to the lattice-like scaly ripples of the bay. Actually I haven’t seen Evans Bay near the northern end of the runway like you describe, it’s usually rougher, which mostly meant landing the C172 to the north after having gone through the washing machine of gusts seaward of Island Bay. Have you seen or studied bending wave drivers, typified by Manger drivers?
AMR-iFi R&D
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Pundit
Post by garym on Jun 18, 2019 22:10:44 GMT 12
I've played with distributed mode drivers, which is sort of the same. A chaotic vibration pattern that creates a coherent sound field. Not enough time to pursue it though. I sampled a few panel materials and a variety of exciters.
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