Hi all,
tired of chasing a ghost, I ordered an 18sound XT120, which is rediculously cheap here in Germany - 17 €, that would be around $20 - to have a waveguide that is widely used and known to work well. If the problem persists, it will be worth investigating further, if the problem dissappears, well, than it did. I hope so.
Best regards, I will post results, but that will take a while, because the waveguide is square and has to be fitted instead of the flush-mounted round dayton.
tired of chasing a ghost, I ordered an 18sound XT120, which is rediculously cheap here in Germany - 17 €, that would be around $20 - to have a waveguide that is widely used and known to work well. If the problem persists, it will be worth investigating further, if the problem dissappears, well, than it did. I hope so.
Best regards, I will post results, but that will take a while, because the waveguide is square and has to be fitted instead of the flush-mounted round dayton.
Hi,
Welcome to the reality of two speaker stereo. That is how it is. Comb filtering of the two wave fronts from two speakers.
The main problems of this phenomena are
1) too high directivity of the horns
and
2) too few early room reflections above about 1kHz.
When the horns have high directivity there will be very little early room reflections. It gets worse if you have added room absorbtion.
Early room reflections are essentially THE cure to this anomaly. Since they fill the notches so they don't appear as deep and perception of comb filtering is minimised.
As a first aid, try aiming the horns upwards towards the ceiling.
Welcome to the reality of two speaker stereo. That is how it is. Comb filtering of the two wave fronts from two speakers.
The main problems of this phenomena are
1) too high directivity of the horns
and
2) too few early room reflections above about 1kHz.
When the horns have high directivity there will be very little early room reflections. It gets worse if you have added room absorbtion.
Early room reflections are essentially THE cure to this anomaly. Since they fill the notches so they don't appear as deep and perception of comb filtering is minimised.
As a first aid, try aiming the horns upwards towards the ceiling.
That was a very bad idea, absord the side walls, in a home environment. There should be plenty of lateral early reflections in a listening room to make stereo sound good.
Clearly their directivities are not the same then ? Need to see some data.
.
Yeah, I didn't want to turn my speakers towards the ceiling, sorry... 
What I did is, I found some time to install the new waveguides - 18sound XT120 - and this more or less fixed the issue. The XT120 claim to have constant directivity and are widely used (a clone of them is sold in the US under the brand name denovo and also widely used in the DIY scene), so it seems they do a pretty good job. I didn't find any measurements, though. Anyway, listening to music now is fine again, pink noise of course still shows comb filtering effects, but that I knew before.
The absorbers on the side walls do not cover a very large area and they are not very thick. I will though try removing them and see if that actually sounds better and/or how pink noise reacts to it.
All in all I consider my problem fixed.
There was a question about the Behingers. You can easily find the thread where Dr. Geddes measurements of a pair is discussed. He even wrote an open letter to Behringer with congratulations for their excellent design which results in directivity almost as good as the speakers he builds. So since the Behringers worked very fine in my room as it is even with absorbers, naturally I didn't really believe them or my room to cause what I heard.
What I did is, I found some time to install the new waveguides - 18sound XT120 - and this more or less fixed the issue. The XT120 claim to have constant directivity and are widely used (a clone of them is sold in the US under the brand name denovo and also widely used in the DIY scene), so it seems they do a pretty good job. I didn't find any measurements, though. Anyway, listening to music now is fine again, pink noise of course still shows comb filtering effects, but that I knew before.
The absorbers on the side walls do not cover a very large area and they are not very thick. I will though try removing them and see if that actually sounds better and/or how pink noise reacts to it.
All in all I consider my problem fixed.
There was a question about the Behingers. You can easily find the thread where Dr. Geddes measurements of a pair is discussed. He even wrote an open letter to Behringer with congratulations for their excellent design which results in directivity almost as good as the speakers he builds. So since the Behringers worked very fine in my room as it is even with absorbers, naturally I didn't really believe them or my room to cause what I heard.
Nice that your problem is fixed and also nice to have another data point.
I was reluctant to merely speculate but this supports a tentative suspicion.
Could this be related to the axisymmetry of the first horns?
Could the new elliptical cross section split up some modes that are very sharp for the circular horn?
Best wishes
David
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