Value of the LEDR test?

[klettermann]

In years gone by, long before DSP, I fiddled with LEDR and soon forgot about it. Now I've rediscovered it HERE so I gave it a shot. To my delight my system seemed to do the stuff described. But no measurements, no clear way to evaluate the results, no path to improvement unless my system is already as good as it gets (highly doubtful!! ). So does anybody use LEDR for anything? It seems entirely subjective. What can it tell us? Comments welcome! Thanks and cheers,

 

[kyuu]

As far as I'm aware the LEDR can you only show you two things:

1) Is your pinnae transfer similar enough to the one encoded in the test files for it to even work?

2) Are your speakers set up for good imaging?

Since there isn't really any LEDR content asides from test signals AFAIK, I'm not sure how useful this is. If the LEDR works well, I guess it means your stereo imaging should also be quite solid also?

 

[Blumlein 88]

I can tell you one set of instances back in the day this LEDR signal was helpful. If you had speakers with 1st order crossovers (e.g. Thiels, Vandersteens, Magnepans with ribbons) such a speaker always has off axis lobing even if on axis the response is smooth. Such speakers are touchy or picky about spacing and toe in angles to get a good overall imaging result and not have odd sounding frequency response. If you used this test to try positions and toe in angles for the best results (you weren't getting perfect, but levels of being closer or further from the goal), this would also result in about the best result all things considered. It was quicker and less ambiguous than listening to several music tracks to get frequency balance and imaging correct. So theoretically your pinna may not match the one used for the recording, but in practice it was close enough for nearly anyone to benefit from using that test track.

 

[klettermann]

Thanks for the info. By coincidence I do have big Maggies and have put a lot of time into their placement. In a perfect world I'd put them a little closer together but room constraints interfere, so placement is a bit of a compromise. Still, at the end of the day, it seems that my pinnae are good enough to hear the LEDR effect and speaker imaging is good. But how much effect and how good? I don't know, but I guess I'll grade the system as a "LEDR pass" and move on. I've become pretty obsessive about REW, Dirac and DSP in general - it's all a new, fun toy to play with. But I don't see an obvious way to measure anything from the LEDR signal that would inform some further optimization strategy. Too subjective. Thanks again and cheers,

 

[klettermann]

Meh! Headphones was slightly better but monitors not so much. That said, Roger Waters "Amused to death" have great effects in stereo.

Huh?