Hiphiphan wrote: "After reading your second post, I realize you’re suggesting the use of additional drivers that are pointed at the wall in FRONT of the listener. This seems like it would be effective for enhancing the illusion of venue cues that came from the front of the venue. But it’s hard to imagine that this creates the feeling of "envelopment," since the reflections are coming from in front of the listener."
Duke responds: My speakers are designed to be used with a lot of toe-in, like about 45 degrees, such that their axes criss-cross in front of the listener. This correspondingly "toes out" the up-and-back firing drivers, so their energy reflects off front wall and/or side wall, and ceiling, before reaching the listening area. And that energy continues to reflect around the room so it arrives from multiple directions, assuming the room isn’t overdamped, though the strongest reflections are those from the front half of the room. You can see an example in the first photo at this link. The stands have an up-and-back firing coaxial driver:
https://parttimeaudiophile.com/2019/06/17/new-gear-from-audiokinesis-and-resonessence-labs-t-h-e-sho...
Hiphiphan: "Two other quick questions if you’ll indulge me:
1. What issues arise from simply using two sets of speakers (one in front, one behind), both playing the identical signal from a regular, two-channel recording, but with the rear set of speakers positioned further away?"
Duke: As long as the rear speakers aren’t too loud, that stands a good chance of being beneficial. If possible, position and/or orient the rear speakers so that their mids and highs arrive at the listening area at least ten milliseconds behind the output of the front speakers. Sound travels slightly more than one foot per millisecond.
Hiphiphan: "2. What about near-field listening? If the speakers are very close to the listening position, almost creating a headphone effect, it seems like might work to create something close to envelopment."
Duke: In my experience nearfield listening can give excellent clarity and imaging, but you still need the reflections delivered from all around to produce envelopment.
The worst possible direction for reflections to come from is the exact same direction as the first-arrival sound. In that situation, they tend to be interpreted by the ears as coloration. This has been established by controlled blind listening tests. So the worst direction for the ambience cues on the recording to arrive from is directly from the speakers. In a nearfield setup the idea is to be close enough to the speakers that they are much louder than the in-room reflections, which does not promote envelopment. When the ambience cues on the recording are delivered from many different directions by the in-room reflections, that’s when they have the best chance of conveying envelopment. In fact multichannel music done right uses the surround speakers to ensure the delivery of the recording’s ambience information from many different directions.
I have experimented with optimizing the arrival direction of the additional reflections, and with optimizing their arrival time. I found (to my surprise) that the arrival time matters more.
Duke
