Speaker upgrade for classical music

1) You mentioned that envelopment can be achieved through a multi-channel system. Do you mean basically playing a normal, two-channel recording through two sets of speakers, one in front of you and one behind, with both sets playing the exact same thing? Or do you mean using special recordings that were intended to be used specifically with multi-channel systems (in which what the front set of speakers plays is not identical to the rear set)."

Duke replies: I mean the latter: Special multi-channel recordings with the reverberation (ambience cues) delivered through dedicated surround speakers. Not that this is necessarily the only way a multichannel system can deliver envelopment, but it’s what I had in mind.

Hiphiphan again: "2) The other way to achieve envelopment you describe is as follows: "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..., 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,...we have envelopment." I’m confused by this. If we are deliberately emphasizing later-arriving reflections created by OUR OWN ROOM, how is this the same as "the venue cues on the recording dominate over the playback room’s...signature"? By definition, if we’re trying to make certain room reflections dominant, then we’re not making the reflections captured on the recording dominant."

Duke: EXCELLENT QUESTION!!

Basically I’m advocating chopping the radiation pattern of a normal speaker into two pieces, aiming one piece at the listening area, and aiming the other piece in a different direction such that it arrives after some time delay, because this works WITH rather than AGAINST the playback room and the ear/brain system.

The proper role of the in-room reflections is to effectively deliver the venue cues on the recording, whether they be real or engineered or both (this isn’t their ONLY role - more on that later). However they also inevitably contain “small room” cues inherent to the playback room. The ear/brain system will accept (or synthesize) whatever sense of acoustic space is most plausible, and USUALLY this is dominated by the playback room’s cues.

The ear gets its information about the size of a room from two main sources: The early reflections, and the decay characteristics. The approach I advocate disrupts the “small room signature” cues that the early in-room reflections would normally convey, and effectively presents the decay cues which are on the recording.

The time delay between the first arrival sound and the “center of gravity” of the reflections tells the ear/brain system about the room size. If we can push that center of gravity back in time, we can disrupt and weaken the playback room’s inherent small-room signature. The approach I advocate does this by a) minimizing early reflections and b) adding MORE reflections which arrive at least 10 milliseconds behind the direct sound.

Now as long as the playback room isn’t overdamped, this additional reverberant energy results in a lot of spectrally-correct reflections, which effectively present the venue cues (and in particular the decay cues) that are on the recording. And part of this "effective" presentation is that the venue cues come from all around. (Directly from the loudspeakers is the WORST possible direction for reflections to come from, which is why overdamped rooms don’t convey envelopment). With a good recording, the venue cues carried by the reflections dominate and we can close our eyes and enjoy the illusion of envelopment. It’s not a perfect illusion of course, but imo it’s a worthwhile improvement to a normal stereo image.

The OTHER role of the in-room reflections, assuming they are spectrally correct, is to enhance timbre, much like the reflections in a good recital hall. Since the path lengths are shorter than in a recital hall we run the risk of degraded clarity if the in-room reflections are too loud, so I give the rear-firing driver array a user-adjustable volume control.

I realize these ideas are unorthodox and somewhat counter-intuitive. In particular it is counter-intuitive to think that by ADDING reflections, we might actually perceive MORE of the recording venue and LESS of the playback room. After hearing an abbreviated version of my schpiel at an audio show, Andrew Quint of The Absolute Sound pulled out a thumb drive and said, “I’d like to challenge that”. Obviously he was skeptical too! We played the piece on his thumb drive and I asked him how we did. He said, “It passed. It’s not a gimmick; it works. I clearly heard the acoustic signature of the Concertgebouw.”

Quoting from Andrew’s version of that incident:

"The recording was a FLAC rip of the CD layer of an RCO Live SACD: Shostakovich—Symphony No. 15; Concertgebouw Orchestra/Bernard Haitink conductor. It’s a live recording from March of 2010 (Haitink made a much earlier recording of the same piece with the London Philharmonic; he was the first person to record all the Shostakovich symphonies.) For a couple of years, this has been my go-to symphonic recording when I have just a short time to get a sense of an unfamiliar system. It’s an excellent performance, something I can listen to repeatedly without going nuts, which is important at a show. In terms of audiophilia, it’s an extremely detailed yet atmospheric representation of an orchestra, with excellent dynamics and fully characterized instrumental colors (bells, solo turns by violin, flute, piccolo, string bass, trumpet, etc.) And—with the right audio gear—it successfully renders the essence of (IMO) one of the greatest 3 or 4 concert halls on earth, the Concertgebouw (thus the orchestra’s name) in Amsterdam. I’ve heard music there, and there’s truly a sense of sound being present in the air around you.

“The multichannel program on the RCO Live SACDs (there are dozens) get this last aspect right; so did the Bienville Suite, nearly to the same degree, despite the presence of only two channels. My concern when Duke told me about the rear-firing drivers was that this would impart some generic, Bose-like spaciousness to the recording, but that wasn’t the case—what I heard was the unique acoustic signature of the Concertgebouw."

What we do has evolved since Andrew wrote that in 2016.

Duke