Greg,
Great looking speaker, love it! According to Gary, his sealed cab for the GPA woofer is 3 cu. ft. Pictures can of course be deceiving, but your's looks bigger than 3 CF, maybe because it appears to be tall. Can you please let us know what the volume is? Also, did you perhaps at some point in the past measure the T/S parameters of the GPA-416?
Earl,
you or thou (choose the one, which fits) participated in the "Fixing the stereo phanton center" topic, hence you or thou should know, that most human beings each have two simultaniously working ears, hence at least one ear hears run-time difference between L and R loudspeaker and so comb-filtering. Furthermore, human beings tend to not keep their head fixed to the half-inch for the time span of a whole piece of music, and once run-time difference is different for rite and left ear, comb-filtering cannot become electrically equalized anyway.
As long as one keeps sat and does not hear to the side, these cancellations start within the mid range and do not exceed presence range, because ears are shaded by the head. Now if one stands up and moves around, cancellation frequencies are much lowered. Power response of the whole setup including the listening chamber smears the comb filter at lo frequencies, but at higher frequencies peaks and dips alternate quickly, causing quite a mess.
Uli
you or thou (choose the one, which fits) participated in the "Fixing the stereo phanton center" topic, hence you or thou should know, that most human beings each have two simultaniously working ears, hence at least one ear hears run-time difference between L and R loudspeaker and so comb-filtering. Furthermore, human beings tend to not keep their head fixed to the half-inch for the time span of a whole piece of music, and once run-time difference is different for rite and left ear, comb-filtering cannot become electrically equalized anyway.
As long as one keeps sat and does not hear to the side, these cancellations start within the mid range and do not exceed presence range, because ears are shaded by the head. Now if one stands up and moves around, cancellation frequencies are much lowered. Power response of the whole setup including the listening chamber smears the comb filter at lo frequencies, but at higher frequencies peaks and dips alternate quickly, causing quite a mess.
Uli
And yet, such "mess" is all but inaudible. Come to think of it, it has to be this way, for the same phenomenon has been with us all along our evolution.
I agree, and it's one of the main reasons I like good diffusion in a listening room.
But those reflections will not affect the direct sound before the reflections arrive. During the window before the reflections arrive, comb filtering can occur.
Are there any clues as to how we do process sound into the extremely fine perception of it that we know we have? All the FR 'mess' doesn't effect our perception very much at all. We don't even notice the rapid big shifts when we move our head, that a mic shows up.
Is it more to do with the instantaneous rates of change? I guess that is the differential plot. But then all electronic systems work on differential anyway. Nobody has ever heard an undifferentiated sound wave via electronics.
Searching in the dark here with neither the maths nor psycho acoustic background. But not on my own.
Is it more to do with the instantaneous rates of change? I guess that is the differential plot. But then all electronic systems work on differential anyway. Nobody has ever heard an undifferentiated sound wave via electronics.
Searching in the dark here with neither the maths nor psycho acoustic background. But not on my own.
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I don't understand what you are getting at. The discussion is about using a single microphone to measure two speakers in a room. Nothing about hearing or ears is even relevant to the discussion.
The "you or thou" comment seems unnecessary.
your comment (stated as "you should know"
):does not really make any sense because each ear receives a different signal from each speaker. To have comb filtering we need identical signals delayed in time and that is not what happens with head diffraction. It is much more complicated than simple delay, so the use of the simplistic term "comb filter" is inappropriate.
To understand this you should look at how we hear. A good understanding (of this limited topic) comes from looking at what are called GammaTone filters (You can Google that). These are the closest that we have to the kind of filtering going on in our hearing. These are linear filters and the ear is nonlinear, but for the moment we can ignore that fact.
If you look at the impulse responses of this filter set (it is a filter bank of a multitude of filters) you will see that at HF the impulse responses are very very short, micro-seconds, but much longer at LF, several ms. At HFs the ear has already processed the sound long before any reflections arrive, which is not the case with your microphone measurement (unless you post process the signal.) So you look at the mic change as it moves about in a steady state field and it fluctuates all over the place. But you don't hear this because the ear processes these signals in time and it does this very rapidly ignoring the reflections. You can hear this at LFs, but then the LF changes in space are far less rapid than the HF ones.
One thing that is true is that very early reflections and diffraction do affect things in a less pronounced way when considering "image". Image is very sensitive to small aberrations in the very early signal arrival times.
You are in denial of a big problem, which has existed for over 60 years, when stereophonics was started. We use to show response plots of single loudspeakers, tho half of what we will hear from them is not the single loudspeaker but a mix of two loudspeakers, and tho what matters is not a microphone placed exactly between both loudspeakers but a human being living in front of them. At our ears, both loudspeakers interact with quite deep cancellations at various frequencies, usually not a perfect comb filter but more or less so. And how should I speak to one person of possibly alien interest, either like to a group of persons or like to a single person of probably mutual interest? I do not like language to become dragged down by possi- and probabilities but like it strait, but then I rather get rid of most people anyway.I don't understand what you are getting at. The discussion is about using a single microphone to measure two speakers in a room. Nothing about hearing or ears is even relevant to the discussion.
The "you or thou" comment seems unnecessary.
your comment (stated as "you should know"
does not really make any sense because each ear receives a different signal from each speaker. To have comb filtering we need identical signals delayed in time and that is not what happens with head diffraction. It is much more complicated than simple delay, so the use of the simplistic term "comb filter" is inappropriate.
why bring the duck into it
the question has always been which came first the chicken or the egg
Whether you are using a CD horn system or a typical two way monitor or even something like an MBL omni-directional speaker in a real room you will always have comb filtering effects at some frequencies and in specific positions in the room. Anyone who doesn't understand that is just not admitting the true nature of the sound fields in a room. Now if you want to look at this as a head in a vice situation then so be it, but that is not a very practical application of known acoustical effects of a normal room.
Now back to the Beyond Ariel speaker design to think that this design does not have these same effects with a single horn above a sealed bass enclosure is part of the conversation but not what I would call the design concept for this speaker in the least. Whether Lynn ends up with one or two bass drivers will have little ultimate effect on what has just been talked about, room interactions will still take place. Unless you have a highly treated room some of the conjecture about using cd horns and matching the radiation patterns at the crossover frequency becomes a very limited part of the overall room response that you will have from any type of speaker in a room.
Now back to the Beyond Ariel speaker design to think that this design does not have these same effects with a single horn above a sealed bass enclosure is part of the conversation but not what I would call the design concept for this speaker in the least. Whether Lynn ends up with one or two bass drivers will have little ultimate effect on what has just been talked about, room interactions will still take place. Unless you have a highly treated room some of the conjecture about using cd horns and matching the radiation patterns at the crossover frequency becomes a very limited part of the overall room response that you will have from any type of speaker in a room.
There is some very good info here about head related 2 speaker interference and notches.
http://www.sfxmachine.com/docs/FixingThePhantomCenter.pdf
That paper is the basis for the discussion over on this thread.
http://www.diyaudio.com/forums/multi-way/277519-fixing-stereo-phantom-center.html
Question is whether method in "fixing the phantom center" paper works or not. Since trying to do so would involve not only processing the source from the speaker, but also diffraction and reflection, the solution of which results in different diffraction and reflection. Seems like trying to use a mirror to enhance image quality of a reflected object.
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Q ?
Was there ever a Ariel re-design using a simpler cabinet ? Like what was done with the SEAS THOR being re-invented as FAT THOR using MJK's mathcad models ?
I Have the Ariel drivers and would like to build an Ariel keeping same baffle width and crossover design by Olsen , but an 'easier' cabinet for the woodwork challenged like me..................
Was there ever a Ariel re-design using a simpler cabinet ? Like what was done with the SEAS THOR being re-invented as FAT THOR using MJK's mathcad models ?
I Have the Ariel drivers and would like to build an Ariel keeping same baffle width and crossover design by Olsen , but an 'easier' cabinet for the woodwork challenged like me..................
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