Home High Efficiency Speaker Asylum

Need speakers that can rock with just one watt? You found da place.

[ Follow Ups ] Thread: [ Display  All  Email ] [ High Efficiency Speaker Asylum ]
[ Alert Moderator ] [ Edit ] [ Delete ]

Re: From Wayne Parham - Re: Patentable claim

193.134.170.35

Wayne wrote:
>>>>That's the key here. "Temporarily" That's the point of all this. Moving the offset forward or back, either one is still a compromise. Your defense of the time alignment technique you've used only makes my case even more clear. There is no way to truly time align two different point sources at every frequency and at different positions with techniques as simple as position offset or the use of single-node filters. You can make them aligned at one frequency, and at one position and that is all.<<<<

When the drivers are within 1/4 wavelength of each other you can. Keep in mind that the Unity has limited dispersion and a coaxial arrangement. Together with the carefully chosen spacing and an appropriately designed crossover, this makes off-axis lobing problems a non-issue in the Unity. The ONLY way in which a Unity does not act as a point source is due to the reflections you get from edges of the horn. This is a minor issue and, of course, not unique to the Unity. In fact reflection issues are probably less of an issue in the Unity than in discrete horn systems simply because you have fewer edges. I am sorry you are having trouble accepting that the Unity acts as a point source, but it is the truth.

Wayne wrote:
>>>>I think Davies says it well, "It is one of the fundamental laws of linear systems that if their output depends only on previous input - that is, if they cannot see into the future - then the phase response is completely determined by the amplitude response."<<<<

This is true for linear "minimum phase" systems--phase is related to magnitude by a Hilbert transform, so if you know phase you can calculate magnitude and vice versa. This means that if a minimum phase system has a flat magnitude, it also doesn't have phase shift. I have heard this analogy between minimum phase systems and systems that don't "look into the future" before. It is a simplification that helps people intuitively understand what is required for a system to be minimum phase. However, it only works when talking about linear filters applied in series to a signal, not filters applied in parallel. Crossovers are, of course, filters that are applied in parallel and their output is summed.

First order crossovers are minimum phase--a flat on-axis magnitude response will also not exhibit phase shift. However, higher order crossovers are not minimum phase--they may have flat magnitudes, but they also have phase shift. Systems with flat magnitude and with phase shift are called all-pass systems. They are not minimum phase (phase is not unitquely determined by magnitude), but I wouldn't say that they "look into the future".

John

This post is made possible by the generous support of people like you and our sponsors:
  VH Audio  

Follow Ups Full Thread
Follow Ups
You can not post to an archived thread.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]