Is soundstage just a distortion?

Hi Mapman,

Are you able to rule the room acoustics in your tests as a factor?

I would think that listening from 2 feet away, directly in front of the tweeters, pretty much rules out room acoustics as being responsible for the effect I described.

Maybe listening with headphones would be a good test to see if hearing alone produces the effect.

I would assume that the acoustic effects of the pinnae (the part of the ear that is outside of the head) are a major contributor to the effect I described. Headphones pretty much bypass the pinnae, and of course fire into the ears from the sides rather than from the front, so I'm not sure that headphone listening would provide any meaningful insight with respect to the effect I described.

Best regards,
-- Al

Regarding the question about soundstage height, while I can't say this with 100% certainty, experiences I've had listening to a test record containing half-octave warble tones have led me to believe that our hearing mechanisms perceive certain parts of the treble spectrum, especially in the 7 to 10 kHz area iirc, as originating from a point in space that is considerably higher than the actual source.

If so, musical notes having significant spectral content in that region would tend to be "pulled" higher, along a vertical axis, than notes that don't. That may explain, for example, why a female singer's voice may be perceived as emanating from a point in space that is above the level of the guitar she may be playing.

I haven't done enough experimentation to totally rule out the possibility that ceiling reflections at those particular frequencies were the cause of what I perceived with the warble tones, but I'm doubtful that the leaf/quasi-ribbon tweeters in the speakers I was using at the time had sufficient vertical dispersion to cause ceiling reflections to be responsible.

So in the absence of specific evidence, I would not make the assumption that our hearing mechanisms perceive all frequencies as emanating from the height of their actual source.

Regards,
-- Al

Thanks, Newbee. To clarify, though, what I was saying is that my experiences listening to the warble tones on the test record I referred to led me to believe that it is the nature of our hearing mechanisms themselves, completely independent of reflections from the ceiling (or anything else), that can cause notes having differing frequency content and harmonic structures to be perceived as originating from different heights.

My reference to ceiling reflections was made to indicate that the listening experiments I had done had not been extensive enough to positively RULE OUT the possibility that ceiling reflections were responsible for what I perceived. But for several reasons I was highly doubtful that reflections were the cause, or at least the main cause.

Just now I have repeated the experiment, using my present Daedalus Ulysses speakers, which as can be seen here have a driver layout that is vertically symmetrical, with the tweeters in the middle. In addition to performing the experiment at my normal listening distance of about 11 feet, I also performed it listening very near-field, from about 2 feet directly in front of the tweeters.

The results confirmed my earlier belief. I perceived each half-octave warble above about 5 kHz as originating, to varying degrees, from heights that were WAY above the tweeters, even when those tweeters were just 2 feet away and exactly at ear height. Below about 5 kHz that effect did not occur.

Best regards,
-- Al

05-03-13: Geoffkait
It's a little ironic that there are such things as records and CDs that test for soundstage since the soundstage you get is going to be limited by the, uh, limitations of the system you play them on. Kinda like seeing an ad for HDTV on your old fashioned 90s Panasonic. The HDTV picture quality in the ad is going to be limited by the constraints of the Panasonic.

I don't see any irony there, Geoff.

The basic purpose of a test record or CD is to facilitate assessment and identification of the "limitations of the system you play them on."

It seems fundamental that when you want to test something, the performance of the test equipment (in this case the record or CD), in terms of accuracy, quality, etc., should be much better than the corresponding characteristics of what you are trying to test.

Regards,
-- Al