Near field listening

waveformuser -- Fri, 12/07/2007 - 15:06

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.

HarrisonS -- Sat, 12/08/2007 - 12:04

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.

RobertGreene -- Tue, 06/17/2008 - 15:41

(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

Robert Harley -- Tue, 06/17/2008 - 17:16

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.

Veronica -- Mon, 11/15/2010 - 15:09

While I have not studied the science or the reasons for this phenomenon I do not believe that acoustics have much to do with it. 
I first experienced this in the engineering lab at my old job in the Renkus-Heinz factory.

Out in the warehouse in the midst of machinery, cages filled with parts and completed items, forklifts and test benches and stations for many different components and completed systems we had a demo area.  The Demo area was carpeted and surrounded by huge heavy sound dampening curtains.  However even before the curtains we would hear sounds and wonder if it was live or recorded.  All too often I would leave the lab to find a few people playing back pre-recorded music and be disappointed.  But other times members of a known band would be testing out/evaluating the equipment.  More than once I dismissed this sound which sounded too good to be reinforced only to find out that some famous musician had in fact just played around on some of our speaker cabinets and I missed it not being aware that it was the real deal this time.  (Amazing, the boy who cried wolf thing really DOES work).  One that made me particularly mad was when Neil Schon was there and nobody told me.  I was enjoying the sounds while WORKING of all stupid things.

I was so impressed with the Renkus-Heinz product that I purchased several and use them in my home.  Years later it is accepted that this is how things SHOULD sound and I am used to expecting things to sound EXACTLY the same in my home as they do in the real world.  It is everywhere else where I am shocked , appalled and disappointed.  My neighbors are also quite accustomed to the clarity and fidelity of the Renkus-Heinz product(s) and the sounds coming from my home.  Even through the dual pane windows, it is clear that there is ZERO distortion and we can open a few windows and enjoy serious clarity and articulation outdoors at SPLs sufficient to make the house, doors, windows and light fixtures buzz (if we just wanted to be obnoxious).   Normally, we just play music at a pleasant volume depending on the mood.  Imagine 6 cabinets each rated at 124 dB SPL RMS plus another dozen fills powered by a dozen high fidelity amplifiers.  (All bi-amped or tri-amped).  Amps include: Renkus-Heinz P3500s, FBT P2950s the same amp and speaker combinations that were called the "Rolls Royce of Pro Audio".  The real benefit of such overpowered equipment in a home is that we never actually push it anywhere near the point of distortion much less damage.  The 6 big cabinets each have a McCauley LF Driver, (2 are used as Subs) and the 4 remaining each have 12" complex conic horns driven by dual 3" RH compression drivers.  The stunning clarity of 6" of high fidelity drivers going into a 12" horn means that the most subtle mid and high nuances are heard with clarity unsurpassed by tweeters or constant directivity horns.  The totals of house main speakers/subs is 7' of LF (Low Frequency) and 4' of Complex conics.  We have home theater speakers scattered for use as fills and surrounds.  Dont even want to bother counting all those. 
Have heard and been amazed by both B&W and Krell.  So not  surprised to hear that you are having the same experiences with your toys, er I mean systems. 
 
B&W rave:
First B&W experience was in an executive conference room on a studio lot where I was tasked to troubleshoot some system issues and experienced the stunning clarity of B&W.  I always thought of home theater and consumer speakers as overpriced toys that I would use for audio in a bathroom or hallway but never anything worthy of note.   Needless to say, B&W won me over and made a believer out of me.  The clarity was fantastic for a small system, tame even in a room with large windows.  I was able to distinctly perceive subtle speech impediments in television actors which is one area where lesser systems consistently fail.  While it did not have the thunderous bass of my rig, it was certainly more than ample for the room that it was in with plenty to spare.  Have NOTHING bad to say about B&W and had I known about them sooner, I certainly would have chosen B&W over some of the other speakers in my home.  (Not the Renkus-Heinz though, I will be buried with my 4 RH speakers that have the 12" complex conic horns). 
Have heard Krell and Meridian demos.  LOVED them both but got sticker shock. 
Okay, so back to reality.  Sound is SUPPOSED to sound REAL.  that is the point.  You are among the few who understand that.  But I do not believe that acoustics are the reason, it is your gear.  The sweet spot is the best spot, but you are putting out sweet sound everywhere and there will be places (even outside) where it will still sound incredible.  (When I turn it up and open the windows, the sweet spot can even extend down the street a dozen houses or so).  giggles

All content, design, and layout are Copyright © 1999 - 2011 NextScreen. All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.