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Revolution in loudspeaker technology

Mivera

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Frank Dernie

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NXT were doing this about 15 years ago.
Knowing NXT it is likely these people are violating one of their patents.
 

iridium

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NXT were doing this about 15 years ago.
Knowing NXT it is likely these people are violating one of their patents.

No slight intended: possibly the patent have expired.
15 years + USPTO bullsh_t + bringing to market = length of patent.

Respectfully,
iridium.

ONCE AGAIN I DO NOT KNOW WHERE THESE STRIKE_OUTS COME FROM????????????
 

Frank Dernie

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I don't know where NXT place patents, but their business plan was to patent technology they developed and then sell it, rather than marketing product. They used a friend of mine as a consultant on a lot of the mathematical modelling and building prototypes.
I have NXT supertweeters and some splendid corrugated cardboard "speakers" made to demonstrate the principle to people. The key to making them work well is the nature of the panel to which the exciters are attached and the precise position of the exciter.
Too dense a panel and the efficiency is low and poor output at higher frequencies. The position is crucial so it excites as many modes as possible. If centrally located the lower modes are MUCH stronger giving a horribly peaky response.
IIRC the only practical device which came from the research which started as an idea exactly like this was the BMR which works very well (I have only listened to prototypes) but being modal at high frequencies it has very broad HF distribution which gives a wider listening window but potentially gives more room reflection problems as well.

The Naim Ovator speakers use BMR drivers.

Reading the white paper was a bit of a deja vu moment, almost precisely the NXT spiel I remember!


I suppose what I really mean this is a repeat of old (unsuccessful) technology not any sort or revolution in speaker technology.
 
OP
Mivera

Mivera

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Frank Dernie

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Neat detail design but still a variation on an existing theme, melding dome driver and coaxial driver details.
The spiral reinforcement is another variation on a theme too. Only a FE analysis would show benefita at the design stage. Often the benefits need to be huge to justify the cost of new tooling and manufacturing methods.
I am particularly interested by loudspeakers, partly because they benefit from the sort of analysis I started my career with.
Unlike record players, where I have first hand personal experience, my knowledge of speakers comes via a good friend who is a partner in a consultancy which designs drive units and complete speakers for clients. There seem to be 2 routes followed, one to keep the driver pistonic over its whole pass band, the other to accept breakup and control the damping better.
Frankly I suspect a well engineered speaker of conventional layout can produce very good results nowadays.
 

Cosmik

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There seem to be 2 routes followed, one to keep the driver pistonic over its whole pass band, the other to accept breakup and control the damping better.
There is another factor: how wide to make the pass band. DSP and active amplification gives us transparent crossovers so there is no penalty to using more drivers and smaller pass bands. I think this notion has yet to be accepted in traditional circles, hence the continuing interest in 'unconventional' single transducers that can cover a wide pass band with broad dispersion.
 
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