Sonic impact of downmixing stereo recordings to mono

[Thomas_A]

It does: "the brain" would not average, as you put it, it is about different signal processing chains. As soon as a phantom source is identified, the coloration due to direction dependent ear signals is - spontaneously ignored. If the phantom source collapses, the coloration is perceived. So far the direct observation. The modelling of the effect in the second part of Theile's piece is speculative, sure, but not without reason.

I would go even further in saying, the identification of phantom sources hinders the detection of coloration, may it originate in the HRTF or in the speakers.

Anyway, as you say, phantom is colorful, does it turn to grey once downmixed?

We should foremost acknowledge, that evaluating a speaker is a very unique mode of listening. I'm quite rarely into that, don't know about you

My experience is listening to mono and stereo using both pink noise, music, sweeps and single frequencies in the 500 Hz- 5 kHz while constructing crossovers. I have almost always found a weaker energy around 1-2 kHz vs. 3-4 kHz with stereo setups despite measurements look fine. With music some voices may just be a bit unpleasant. It has ended with a slightly more energy 2 kHz vs. 3-4 kHz. That way it sounds better. But again that is me.

 

[Heinrich]

The Ascilab actually thanks to ...

Great speakers, great concept, vitually all done right. Congrats!

It comes with implications, though: Partly the constant directivity in its lowest octave relies on vertical interference and lobing. This usually results in a slightly different tonality for vertical and horizontal dispersion influencing discrete reflection tonality ...

All directivity talks are void as long as the room isn't taken into account with the same scrutinity.

When it comes to evaluating a speaker model listening to only one of the pair, the chain of premises and conclusions is a bit longer than people think. There are so many uncertanties, caveats and all.

What is the target, especially would it evaluate the fitness for stereo? Presumably not. I think it was meant to identify the technical parameters for a 'perfect' speaker. Once that is done, all the panel testing in mono isn't needed anymore. The parameters, naturally, can be measured instead - today.

To our all surprise it came out: flat, homogeneous. What a shock! (We desperately needed a standard, because 'surround' asked for it, the marketing of certifications.)

Listening to a single speaker is not comparable to listening stereo, that easy. Hence a downmix is not a technical problem in the first place.

 

[Arindal]

this vertical lobing is surprisingly low for a non-coincidential design

I agree, the listening window is not affected. Nevertheless we have a band of almost an octave (0.7-1.4K) which is showing very high vertical directivity index, while the horizontal one is very low (both compared to the neighboring octave 1.4-2.8K). It is impossible to predict the influence on early reflections and resulting diffuse field. Someone with trained ears, experienced with judging reverb, has to give it a listening session.

I think that also depends on the listening distance and closeness to vertical reflections like for example desktop

Yes, it definitely depends on the listening distance. While in a nearfield and desktop situation indeed localization angle and tonality might likely be affected, under mid-field conditions it can have an influence on localization stability, in case our ears can determine the differing positions of ´real sources´ through early reflections in contradiction to phantom sources. Again, someone experienced has to try it.

 

[RickS]

No speaker is perfect but, in most cases, should never be designing a speaker towards how the music was recorded.

It is safe to say that Dr. Toole's (and related) research has affected almost every speaker mentioned in this thread so far. Along with Amir's efforts, speaker manufacturers are starting to provide more and more useful specifications than in the past. Is there room for improvement, sure. But, at this point, the next big advancement opportunity is in how music is recorded and produced. If better music production standards existed, likely this thread would not.