Hi ssm,
I’d like to comment about one of the characteristics you mentioned:
"What I want: speakers... that really reproduce the expansiveness of the symphony hall or church."
In home audio there is a competition between the acoustic signature of the venue (which is on the recording) and the acoustic signature of the playback room. In most home audio systems, the "small room signature" of the playback room dominates.
Imo we can look to what works well in the concert hall for inspiration. Quoting acoustician David Griesinger:
"Envelopment is the holy grail of concert hall design. When reproducing sound in small spaces [home listening rooms], envelopment is often absent."
"Envelopment is perceived when the ear and brain can detect TWO separate streams: A foreground stream of direct sound, and a background stream of reverberation. Both streams must be present if sound is perceived as enveloping."
Implied by the TWO STREAMS paradigm is a time gap in between the direct sound and the strong onset of reflections. This is desirable in the concert hall AND in home audio, though the timescales are less in home audio because the reflection path lengths are shorter. How long of a time gap is adequate? Griesinger again:
"Transients are not corrupted by reflections if the room is large enough - and 10ms of reflections free time is enough."
We can get the 10 milliseconds of reflections-free time (in the horizontal plane at least) in a room the size of yours by using speakers which are directional enough to avoid putting much energy into the same-side-wall early reflections. But we also need to have a significant amount of energy in the subsequent background stream of reverberation. There are several possible ways of accomplishing this, one of which is to use a multichannel system.
Recall that there is a "competition" between the venue cues on the recording and the small-room signature of the playback room. It is the EARLIEST reflections which are the most responsible for small-room signature (though decay time can also play a role). By minimizing the energy in the early reflections, and having plenty of spectrally-correct energy in late-arriving reflections, and using diffusion instead of absorption (kudos for your use of diffusion!), we can use these later-arriving reflections to effectively present the venue cues on the recording. And when the venue cues on the recording dominate over the playback room’s inherent small-room signature, if it’s a good recording, we have envelopment.
So envelopment is elusive in home audio, but can be accomplished by applying the principles that work well in the concert hall, which usually calls for some creativity (unless the playback room is very large). Envelopment isn’t the ONLY thing that matters of course, but it can be borderline transcendental when it happens.
I can go into some specifics if you’d like. Doing so would involve describing things that I’m commercially involved with.
Best of luck with your quest!
Duke
I’d like to comment about one of the characteristics you mentioned:
"What I want: speakers... that really reproduce the expansiveness of the symphony hall or church."
In home audio there is a competition between the acoustic signature of the venue (which is on the recording) and the acoustic signature of the playback room. In most home audio systems, the "small room signature" of the playback room dominates.
Imo we can look to what works well in the concert hall for inspiration. Quoting acoustician David Griesinger:
"Envelopment is the holy grail of concert hall design. When reproducing sound in small spaces [home listening rooms], envelopment is often absent."
"Envelopment is perceived when the ear and brain can detect TWO separate streams: A foreground stream of direct sound, and a background stream of reverberation. Both streams must be present if sound is perceived as enveloping."
Implied by the TWO STREAMS paradigm is a time gap in between the direct sound and the strong onset of reflections. This is desirable in the concert hall AND in home audio, though the timescales are less in home audio because the reflection path lengths are shorter. How long of a time gap is adequate? Griesinger again:
"Transients are not corrupted by reflections if the room is large enough - and 10ms of reflections free time is enough."
We can get the 10 milliseconds of reflections-free time (in the horizontal plane at least) in a room the size of yours by using speakers which are directional enough to avoid putting much energy into the same-side-wall early reflections. But we also need to have a significant amount of energy in the subsequent background stream of reverberation. There are several possible ways of accomplishing this, one of which is to use a multichannel system.
Recall that there is a "competition" between the venue cues on the recording and the small-room signature of the playback room. It is the EARLIEST reflections which are the most responsible for small-room signature (though decay time can also play a role). By minimizing the energy in the early reflections, and having plenty of spectrally-correct energy in late-arriving reflections, and using diffusion instead of absorption (kudos for your use of diffusion!), we can use these later-arriving reflections to effectively present the venue cues on the recording. And when the venue cues on the recording dominate over the playback room’s inherent small-room signature, if it’s a good recording, we have envelopment.
So envelopment is elusive in home audio, but can be accomplished by applying the principles that work well in the concert hall, which usually calls for some creativity (unless the playback room is very large). Envelopment isn’t the ONLY thing that matters of course, but it can be borderline transcendental when it happens.
I can go into some specifics if you’d like. Doing so would involve describing things that I’m commercially involved with.
Best of luck with your quest!
Duke