That (Mantaray) horn is a mess of reflections and diffractions. That he chose seven events and marked them as HOMs, and at the same time three of those marked as "diffracted waves" on another picture is nothing but a mess as well. How could you take anything from that?
Last edited:
All you have to do to prove or disprove this is take a measurement....raising directivity raises direct energy....direct energy is always more accurate than indirect
In free field....the only measurement you'll get is direct energy. In the room, I think you can see the relationship between direct vs indirect energy (ie reflections)
This a big oversimplification. Getting the right balance of indirect energy at the right time and from the right direction with the right spectrum is a tricky thing to do and is one area where musical style and personal preference play a large part in what one individual may pick that another does not like at all.
The problem is, as I've just found out, that the frequency response, at least how ARTA calculates it, stays minimum phase even if a room reflection is included in the time window. Basically it seems I can't do anything that would make the FR non-minimum phase above ~500 Hz.
That makes the whole excess group delay reasoning seriously flawed, I would say. Now I'm really confused as I thought that diffractions and reflections would cause some excess phase in the overall FR but it seems they don't
The problem is, as I've just found out, that the frequency response, at least how ARTA calculates it, stays minimum phase even if a room reflection is included in the time window. Basically it seems I can't do anything that would make the FR non-minimum phase above ~500 Hz.
That makes the whole excess group delay reasoning seriously flawed, I would say. Now I'm really confused as I thought that diffractions and reflections would cause some excess phase in the overall FR but it seems they don't
Reflections cause several sources. Can´t be minimum phase. Can be seen with Clio.
Sorry, made an error in hurry....
Minimum phase ocoures only when there´s no time invariant parts in the amplitude responce. Minimun phase is calculated (and this from memory, my memory) via some sort of Hilbert transformation from the amplitude responce. The calculation can´t know what part is just ripple or room reflections.
To get "real excess delay" the sample must be "clean" of extra stuff.
Minimum phase ocoures only when there´s no time invariant parts in the amplitude responce. Minimun phase is calculated (and this from memory, my memory) via some sort of Hilbert transformation from the amplitude responce. The calculation can´t know what part is just ripple or room reflections.
To get "real excess delay" the sample must be "clean" of extra stuff.
Are you sure that you want to make this statement. It implies that all parts are time variant which is contrary to all signal processing concepts since they consider only time invariant signals - time invariance is always assumed.
My idea was to look at the difference between the minimum phase (calculated from the measured amplitude response) and the actual measured phase. Could you show how does that excess group delay look like with a recflection included? Your previous EGD plot also suggested minimum phase and I suspect it won't change with the reflection.
(I assume all pure delay is removed from the picture but that's just an unimportant detail.)
Last edited:
Maybe someone with a more fresh theoretical knowledge would know this - how is the frequency response supposed to change if we just repeat the impulse response and calculate the FR from that?
So it will be some comb filter but will it be minimum phase? It seems so.
I think I have to install and finally start using Octave.
So it will be some comb filter but will it be minimum phase? It seems so.
I think I have to install and finally start using Octave.
Last edited: