Near field listening
waveformuser -- Fri, 12/07/2007 - 16:06
My system consists of a stereo pair of Waveform 17 speakers triamped (as required) by Bryston amplifiers (in my case a pair of Bryston 8B st's with two of the four modules per side strapped for the woofer sections). The speakers are housed in a 16 by 19 foot room with a 12 foot cathedral ceiling. The speakers are along the short wall, with the radiating centers of the woofers 4 feet from the front wall and 3.5 feet from the side walls. They are 8 feet apart (tweeter to tweeter), and I usually sit at the apex of an equilateral triangle, ie, 8 feet from each speaker
For those who are unfamiliar with the Waveforms, they consist of a truncated pyramid base containing two vertically stacked 12 inch woofer, with the lower rim of the bottom-most woofer essentially at floor level. Sitting atop the base truncated pyramid is an adjustable "egg" made of aluminum, and housing a 6.5 inch doped paper midrange and a 1" silk domed tweeter. Crossovers are 4th order L/R filters at about 400Hz. and about 1800 Hz.
I have lived with these speakers happily for 7 years, and am still quite pleased with them especially vis a vis many high end systems I have heard.
Recently, I succumbed to a bout of audiophile neurosis (it occurs somewhat regularly about every 7 years), and I decided to try listening from different positions. The first thing I noticed is that the speakers sounded fantastic from the adjacent room (There is a 9 by 10 foot archway between the rooms). Indeed, small groups and singers sound so realistic from that location that, with a very good recording, the listener can and often is fooled into believing that the performers are in the adjacent (listening) room, but around the corner out of sight. The effect is continuous, and lasts for minutes, not seconds. Several audiophile listeners have been amazed by this effect.
I gathered from this effect that the speakers have a relatively flat, and in any case benign, total radiated power response, which sounds quite impressive when room modes are partially ameliorated by moving into the adjacent room.
Next, I tried listening an longer distances. From my usually 8 foot distance the sound image is very close, apparently "in the room", lateral imaging and localization are VERY precise, but depth illusion is slight and the sweet spot relatively small.
As I moved backward, the sound image moved further away even faster, and the upper midrange and highs smoothed out considerably. At about 10 feet (only two feet further than the usual position) the lateral spread of the image smoothed into a cohesive whole, and clear-cut "depth" appeared. Listening is much more relaxed, and the brain no longer has to "work" so hard to make sense out of the illusion.
I presume the latter effect has something to do with driver integration. Does anyone have comments on this effect.
I was very much interested in some of your observations regarding imaging and the perception of highs and midrange versus listener distance and position in the room. I have indeed made similar observations with my living room system.
The room is also about 16 feet deep, but probably about 25 feet wide, with a conventional flat, acoustically treated ceiling at about 8 1/2 feet. The speakers, a pair of B & W 801 Nautilus units are about 11 feet apart, tweeter to tweeter. They are driven by a Krell KAV-1500 5 x 300 watt amplifier in a bi-amped configuration.
With the Krell amplifier, I find that the sweet spot is absolutely huge, and that the sound image does not collapse to the nearest speaker as one moves to the side. In fact, the sound image remains intact even at absurdly great distances to the side. By contrast this was not the case with these same speakers using lesser amplifiers.
One difference in my listening room is that it is L-shaped with an extension on the left side extending back an additional 12 - 15 feet. As I move back in the central area, I find not only an improvement in the integration of the sound image, but exactly as you report, a continual smoothing out of the highs and upper midrange. This effect continues as I move back in the L-extension, even though it is off to the left side, and thus not ideal.
The imaging effects can, to a large extent, be understood in theory by realizing that the speakers are forming a holographic image in sound waves. This can be modelled by treating each driver as a point source. You can see from this how critical phase integrity of the amplifier is in preserving this hologram.
Harrison S.
(In response to the Waveform owner's experience)
I recall the Waveforms vividly. (I still hear from designer John Otvos occasionally, albeit on non-audio subjects).
The Waveform model in question does indeed have a quite uniform power response--that was one of the major design goals. So it should sound quite well balanced at distance, as apparently it does.
The difference between listening to speakers fairly close to(not really near field in the technical sense, but what people call that anyway) and much futher away is indeed quite a large one. Probably closer up is closer in fact to what the recording engineer had in mind(or at least what he or she heard--most monitoring is done close to the monitor speakers). But that does not mean you have to like it better. Recordings differ as to their intent. Some hope to put you in the original acoustic space. For that , you are probably better off to listen primarily to direct sound.
But others are made expecting people to add in the sound of your own room. A close miked vocal listened to in near-field tends to sound like a person singing out of doors!--such recordings were made expecting people to hear them with their own room sound added.
The main problem with adding a lot of the sound of your own room is
that the person or people who made the recording had no way to know anything about your room so in effect you are adding an unknown(to them) quantity. But if you like it, I do not see any harm in it.
Personally I like to hear a lot of direct sound--usually. But sometimes late at night, I turn out the lights and sit at the far end of my living room with the speakers not playing too loud and imagine I am in the balcony of some big hall...
Whatever floats your boat. But the closer up sound is more like what is really on the recording in some sense to my mind.
Robert E. Greene of TAS
I agree with Robert E. Greene that the less coloration imposed by the room, the closer we get to what's on the recording. Killing the sidewall reflections and floor-and-ceiling bounce goes a long way toward reducing room-induced colorations.
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