[rollei_list] Re: Completely OT- Loudspeaker info
- From: "A. Lal" <alal@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Wed, 16 Feb 2005 01:14:44 -0500
Richard,
LR xovers work just fine. Many companies, KEF, Harmon, B&W, to give a
few examples, use these now in their commercial products. In his
designs linkwitz uses all pass filters to introduce delay when needed.
See his first design, the Phoenix, for full details on the xover. He
gives the full xover circuit diagram.
The shape of the frame - it is not a cabinet in the traditional sense -
is intended to optimize the on and off axis frequency response to get as
uniform a power response as possible, while not generating cavity
resonances.
You are quite wrong in stating that dipoles are based on Linkwitz's
misunderstanding of how speakers radiate. Have a look at the room
acoustics section on his site.
Just curious, where is the audiophile hype? On the review page?
Regards,
Akhil
> -----Original Message-----
> From: rollei_list-bounce@xxxxxxxxxxxxx
> [mailto:rollei_list-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
> Sent: 15 February, 2005 19:09
> To: rollei_list@xxxxxxxxxxxxx
> Subject: [rollei_list] Re: Completely OT- Loudspeaker info
>
>
>
> ----- Original Message -----
> From: "Jerry Lehrer" <jerryleh@xxxxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Tuesday, February 15, 2005 10:06 AM
> Subject: [rollei_list] Re: Completely OT- Loudspeaker info
>
>
> > Akhil,
> >
> > We have had Likwitz as a guest speaker at our audio club.
> >
> > I am intimately familiar with his and his associate,
> > Riley's,
> > theories on crossovers
> >
> > I have an active crossover in which I can plug in a card
> > which can be configured to any order. The Likwitz-
> > Riley 2nd order is not to my liking.
> >
> > Jerry
> >
> > "A. Lal" wrote:
> >
> Boy is this a name from the past. I still worked for HP
> when Linkwitz published his paper on crossovers. He was not
> the first to suggest the use of low level crossovers nor of
> phase matching crossovers. I remember my friend Richard
> Heyser, who had some fame in audio himself, being very
> skeptical of this system.
> Low level crossovers and individual amplifiers are a very
> good idea for several reasons but this is a different issue
> from the nature of the crossover itself. Crossovers are
> still something of a compromise but the ability to introduce
> delay at will using digital circuitry allows a much closer
> approach to the ideal where the acoustic fields of the
> individual speakers add in a way that approximates a single
> source.
> I have no idea what he is doing with the very strange
> looking cabinets shown on the web site. Dipole suggests to
> me that the backwave is being radiated directly. I remember
> some talk of dipole speakers in the distant past and, by
> memory, that the idea was based on a misunderstanding of the
> way loudspeakers radiate. The text on the web site is chock
> full of the sort of hype which is so familiar in consumer
> audio. My once golden-ear hearing is no longer good enough
> to make judgments about some aspects of audio system
> performance but I can still tell the difference between
> loudspeakers, at least other than the very top frequencies.
> It would be interesting to compare is speakers with good
> conventional systems.
> Many years ago I worked with Dick Heyser on his method of
> making acoustical measurements called Time Delay
> Spectrometry. I tried at the time to get HP to buy the Cal
> Tech patents, they wouldn't and assured me that the system
> wound't work. In fact, I was making such measurements using
> a standard HP spectrum analyser at the time! HP then tried
> to break the Cal Tech patent. Cal Tech has very good patent
> attorneys so they had no luck. Cal Tech would have sold the
> patent rights for very little so I think there was a large
> dose of "not invented here" about the whole thing. Another
> company finally picked them up and made the equipment
> commercially. HP had to modify the tracking generator in its
> spectrum analysers to avoid an infringement.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
>
>
>
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