Bjorn
Thanks for those.
Clearly the "matched source" is not ideal for the AH-425, it would work better with a -6 dB/oct source. My main comment would be is that these two decices are not even remotely comparable as they are clearly doing different things. The AH-425 is smoother, but its also not even remotely CD. There is basically nothing new there.
Thanks for those.
Clearly the "matched source" is not ideal for the AH-425, it would work better with a -6 dB/oct source. My main comment would be is that these two decices are not even remotely comparable as they are clearly doing different things. The AH-425 is smoother, but its also not even remotely CD. There is basically nothing new there.
When you use equalization, both horn/guides have different requirements. The LeCleach horn should not have the filter, and the OS wave guide should.Kolbrek said:Great. Then here is the 'Matched Source' polar maps for the OS waveguide (once again, but in full resolution) and the AH-425 Le Cléac'h horn (lower plot).
I will leave comments to others. I'm just providing the data for your amusement, and then I'll take a long easter break
Bjørn
soongsc said:
Argumentative and pointless. One has a target/goal and attempts to realize it. Seems to me that if CD is that target, then the judgement is precisely what was stated. One has CD as a design requirement, the other does not. Different goals. If CD is not their target, then it would seem that this thread is not their interest.
My impression is that no matter what anyone says, you have a comment or remark, whether appropriate or not. You just can't help yourself on that.
Dave
Well, I do think it's misleading when comparing data and commenting. In such a way. If the subject was titled OS wave guides or CD wave guides, then we should not talk about other kinds.dlr said:
Maybe its a good idea to ask the moderators to modify the subject title to be more specific.
Man, I must have really been reviewing too many engineering documents before I retired.
soongsc said:
The subject is clear, its about waveguides, not horns. Waveguides are well defined, IMO, and horns don't meet that definition. It is widely agreed that a waveguide is principly a directivity device while a horn is principly a loading device. Hence the topic hear is CD. Its inherent in the title.
gedlee said:
And you think that Bjorn posting this is okay? Clearly we are looking for some amusement here.
Kolbrek said:Great. Then here is the 'Matched Source' polar maps for the OS waveguide (once again, but in full resolution) and the AH-425 Le Cléac'h horn (lower plot).
I will leave comments to others. I'm just providing the data for your amusement, and then I'll take a long easter break
Bjørn
polar interpretation
Unless I'm mistaken, an "ideal" polar would be "all reds", using the color convention in the above plots, in a rectangular section from the lower frequency cutoff (maybe ~ 1 Khz) upwards on the "Y" axis to the angular spread (~ 45 degrees), then across to the frequency extremes (~ 10 Khz or so) with any contour lines showing smooth trends rather than sharp deviations.
But maybe I'm oversimplifying??
John L.
Unless I'm mistaken, an "ideal" polar would be "all reds", using the color convention in the above plots, in a rectangular section from the lower frequency cutoff (maybe ~ 1 Khz) upwards on the "Y" axis to the angular spread (~ 45 degrees), then across to the frequency extremes (~ 10 Khz or so) with any contour lines showing smooth trends rather than sharp deviations.
But maybe I'm oversimplifying??
John L.
Thats correct, but keep in mind that the polar response can't change instantly. So an ideal response would be a flat plataue from the low frequency to the high frequency (ideally this would be 0 Hz - 50 kHz, but thats not possible). Basically a decade is about the best bandwidth that we could expect. The plots would thus be red from the low to the high frequency out to the design angle (vertically) and fall off smoothly on all sides.
TYpically there will be vertical ridges indicating a resonance, or arcs indicating diffraction. There can be spots of low and high when there is multiple diffraction, or diffraction along a line or a curve that interact and add and subtract at various frequencies and/or angle.
TYpically there will be vertical ridges indicating a resonance, or arcs indicating diffraction. There can be spots of low and high when there is multiple diffraction, or diffraction along a line or a curve that interact and add and subtract at various frequencies and/or angle.
One last post before I take my Easter break
I basically did what Earl said he would do in post 2469.
There is btw no EQ applied to the plots. See attachment for details on the "matched source" concept, from AES preprint 1038, "What's so sacred about exponential horns", by Keele.
Bjørn
soongsc said:
And you think that Bjorn posting this is okay? Clearly we are looking for some amusement here.
I basically did what Earl said he would do in post 2469.
There is btw no EQ applied to the plots. See attachment for details on the "matched source" concept, from AES preprint 1038, "What's so sacred about exponential horns", by Keele.
Bjørn
Attachments
I think it becomes clear that whenever a name is involved with a design in any thread, it will be defended to death. There is just no metrics of merits applied, and possibly it isn't possible to apply such either.angeloitacare said:
I think it's fine to bring in subjective listening evaluation. In the beginning, it was mentioned that some people thought they sounded dull, later there were many good words. That was great because you get impressions from both sides which clearly indicates preference diversity. It could also be some design improvements at different times.
There is an audiophile here that really has a big room. Whenever people first come to his place and listen, he asks them to express 5 areas of defficiency. I thought that was neat. Because I personally learn very quickly from various comments from people as well.
From a sales and promotion point of view, the book "The greatest saleman in the world" was very inspiring to me.
Hi Bjorn,Kolbrek said:One last post before I take my Easter break
I basically did what Earl said he would do in post 2469.
There is btw no EQ applied to the plots. See attachment for details on the "matched source" concept, from AES preprint 1038, "What's so sacred about exponential horns", by Keele.
Bjørn
Unequalized plot of a guide/horn of uniform beam over a frequency range would look something like this. Note that without equalization, the SPL will drop with frequency increase, and this is consistent with my measurements. Your plots in post #2540 of the OS wave guide do not show this, and therefore the results are equalized specifically for the OS wave guide.
Now, in the LeCleach horns, due to the fact that the beam is not a uniform pattern over the frequency range, the on-axis response would have pretty much the same SPL. But in your graph, it shows a rise is SPL on axis with the increase of frequency. It seems that the results were equalized using the same high pass filter as used in the OS wave guide.
I beleive a sanity check would be to just measure any horn/guide and compare the results. They should have a similar trend as in the graphs you show.
gedlee said:
For the LeCleach horns, this correction is not necessary. This is what I call, equalization.
Attachments
Re: polar interpretation
Hello Auplater,
your remark is correct and I want to add that the polar graph as given by Bjorn Kolbrek is for a given distance to the mouth of the waveguide.
For another distance the "non red" spots you noticed in the "main lobe" would differ both in frequency and angle.
Someone will surely says: "and then..."
Best regards from Paris, France
Jean-Michel Le Cléac'h
Hello Auplater,
your remark is correct and I want to add that the polar graph as given by Bjorn Kolbrek is for a given distance to the mouth of the waveguide.
For another distance the "non red" spots you noticed in the "main lobe" would differ both in frequency and angle.
Someone will surely says: "and then..."
Best regards from Paris, France
Jean-Michel Le Cléac'h
auplater said:
Seems like yet another post is required
Yes, since here the driver mass rolloff comes in, and the SPL will drop with frequency.
Did you read the explanation of the "Matched Source" concept? The matched source behaves like a driver with zero mass and infinite compliance.
So no EQ is applied in the polar maps (and certainly not EQ specifically designed for the OS), but the effect of driver mass rolloff is removed. In other words, no highpass filter is added, but a lowpass filter is removed.
Bjørn
soongsc said:
Yes, since here the driver mass rolloff comes in, and the SPL will drop with frequency.
Did you read the explanation of the "Matched Source" concept? The matched source behaves like a driver with zero mass and infinite compliance.
So no EQ is applied in the polar maps (and certainly not EQ specifically designed for the OS), but the effect of driver mass rolloff is removed. In other words, no highpass filter is added, but a lowpass filter is removed.
Bjørn