Intrigiung mixture of acoustic loadings? - diyAudio
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Old 25th January 2006, 03:53 PM   #1
Ian J is offline Ian J  United Kingdom
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Default Intrigiung mixture of acoustic loadings?

I've read the recent review on tnt-audio.com of the Magna Acoustica loudspeaker through twice now and I still can't get my head around it. What we appear to have is a design in which two full range drivers are mounted in a bipole config. -but near the top of an open enclosure. This apprently combines a semi-open baffle with some quarter wave/Helomholtz loading and also relying on baffle effects to smooth the response. Must be difficult to model all that in MJKs worksheets! Anyone else intrigued?
Magna Acoustica review
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Old 26th January 2006, 04:34 AM   #2
maxro is offline maxro  Canada
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Interesting. With the drivers near the opening, like that, it really is like blowing on a beer bottle. It would be easy to model, if only we knew the T/S parameters. We need someone who can extrapolate a good guesstimate of them, based on what info is provided.

Max
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Old 26th January 2006, 05:04 PM   #3
Ian J is offline Ian J  United Kingdom
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Well, it's going to be a high Qts driver as undersized magnets are mentioned. This looks to me like a design that was arrived at very empirically - I'm not sure how programs cope with large upward firing vents (see the thread on Terry Cain's BIB for how this might even out the response). I just don't see how any dipole character isn't going to be drowned out by colouration from a lightly damped pipe/resonator. Though I'm getting tempted to saw out the top of my floorstanders to see what will happen! But as they are standard 2 ways with a low qts driver it's bound not to work...
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Old 26th January 2006, 05:20 PM   #4
MJK is offline MJK  United States
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Must be difficult to model all that in MJKs worksheets! Anyone else intrigued?
It is an interesting design.

It is not that difficult to model an upward firing vent and this geometry. Finding the time to reconfigure the models is the most difficult problem.
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Old 27th January 2006, 09:04 AM   #5
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No hurry Martin, you've got enough on upgrading all the existing sheets etc, but when you do have time to add this facility, it should be interesting to see what it can bring to designs...

These boxes are really quite intriguing. I like creative ideas, providing they work properly, and this one is certainly very different from the norm, though I'm blowed if I can see how they can call them dipoles. Nice to see them really. I'm not sure they would work like Terry's BIB enclosure though. Those use a rear-wall / corner boundary condition to increase the effective mouth-size and damp reflections back down the line according to Martin. As these are bipoles, that precludes their being placed near a rear wall. Probably. (Note cunning hedging of bets )

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Old 27th January 2006, 11:02 AM   #6
MJK is offline MJK  United States
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No hurry Martin, you've got enough on upgrading all the existing sheets etc,
Not to mention that the Lowther OB speakers are running now and in the final tweaking stage (Oh my God! I can hear and feel the kick drum!). Great dynamics and bass, no BSC filter required, and huge sound. I'll try and post a picture this weekend. My wife hates them.

Then I have a computer upgrade to complete in the next two weeks, my kids are requiring more computer/Internet time for school. Looks like Dell is going to get next weeks paycheck.

But the worksheets are coming along slowly and I hope to post the first TL sheets in March.
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Old 27th January 2006, 11:46 AM   #7
Salas is offline Salas  Greece
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MJK, what do you make out of Horning Hybrid loading?

http://www.6moons.com/audioreviews/horning/agathon.html

P.S. I have listend to them and the review is not far off.
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Old 27th January 2006, 02:31 PM   #8
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Fantastic Martin.

Your wife hates the open baffles? Right, they must sound good then! I'm looking forward to seeing those...

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