All right, you've spent the last six months painstakingly reading reviews and auditioning speakers and you've made a buying decision. You finally lug your new babies home and begin to uncrate them, your palms sweating and your heart pounding in anticipation of the sonic ecstasy that awaits. You carefully choose a location for your speakers, optimized so that they don't block your view of the ficus in the corner or your path to the fridge. As the last binding post is tightened, you sit back in your favorite listening chair and hit play on your CD player's remote. Wait a second, something's not quite right. Where's that great bottom end that the salesman so ably demonstrated in the store? Why do these things sound so bright? If any of this sounds familiar to you, then you may be neglecting one of the most important aspects of audio system setup - correct loudspeaker placement. Sure, you may have taken the time to read and follow the manufacturer's placement recommendations, but these are only rough guidelines and at best, only apply to the average room (whatever that is). Before you start blaming the poor sound of your new loudspeakers on your current choice of speaker cable or the fact that your cat ate your last Shun Mook puck, experiment with the placement of your loudspeakers. You may be amazed at the newfound musicality of your system.
While correct loudspeaker placement is critical to an audio system's performance, actually finding a good location for your loudspeakers can be tricky and time consuming. The loudspeaker setup regimen of most audiophiles I know (myself included), usually consists of what I call the "cabinet waltz". This is the dance during which you repeatedly wrestle your loudspeakers to a variety of positions in your listening room, and for each position, measure the response at your listening seat (during this dance, the loudspeaker almost always leads!). This process continues until a fairly even response at the listening position is obtained. Unfortunately, unless you're friends with a habitual steroid abuser, lugging a large floorstanding speaker around your listening room for several hours can be an arduous task. Luckily, the people at KB Acoustics have come to the rescue with a loudspeaker placement program called Visual Ears.
Visual Ears is the follow-on product to the popular Listening Room program, which was released under the Sitting Duck Software banner. To use the program, you'll require a PC equipped with a 386DX processor or higher, a math coprocessor, a VGA monitor and a mouse. Although Visual Ears officially only runs under Windows 3.1 and Windows 95, I successfully installed and ran it under Windows NT 4.0 for the purposes of this review.
Visual Ears supports a wide variety of loudspeaker configurations, from a single pair of dynamic two-ways, to a front-channel/rear-channel surround setup with two subwoofers. Unfortunately, owners of less-conventional loudspeakers such as electrostatics and horn-loaded systems are out of luck since the program doesn't support them. As far as listening room geometries are concerned, Visual Ears only supports those of the rectangular variety, although flat as well as sloped and cathedral ceilings are supported. For those whose listening environments demand it, Visual Ears gives you the flexibility to place your loudspeakers asymmetrically with respect to the listening seat and room boundaries. I didn't require an asymmetric setup and used the program's symmetric mode exclusively.
While no install program is provided, installation is a snap - just copy the files to a directory on your hard drive from the diskette provided, create a shortcut to VEAR.EXE and you're done.
Before Visual Ears can be of much help finding good positions for your loudspeakers and listening seat, it's up to you to first define the attributes of your speakers and your listening room. I had two quite different pairs of loudspeakers on hand with which to test Visual Ears: the Coincident Speaker Technology Conquest and the ProAc Studio 150 (both reviewed elsewhere in this issue). The flexibility of Visual Ears allowed me to describe each loudspeaker pretty accurately - the Conquest was described as a Dynamic 2 Way with a -3dB frequency of 35Hz, and the Studio 150 was described as a Dynamic 2 Way MTM with a -3dB frequency of 55Hz. The MTM (Midrange-Tweeter-Midrange) type was chosen for the Studio 150 since that speakers' driver complement consists of two bass/midrange drivers flanking a single tweeter. I did not evaluate Visual Ears' support of surround-sound or subwoofer/satellite systems since my system is designed for two-channel audio, and both the Conquest and Studio 150 are full-range floorstanders. Defining my listening room simply consisted of entering its length, width and height since it is rectangular without a sloped or cathedral ceiling.
The nice thing about Visual Ears is that it allows you to move your loudspeakers and listening position about a virtual listening room with the click of a mouse button rather than the tear of a groin muscle. For each combination of loudspeaker and listening positions in the virtual listening room, Visual Ears displays two graphs: the standing wave graph and the frequency response graph.
The standing wave graph displays the relationship between relative sound pressure level and frequency at the listening position. Each standing wave is represented by a small vertical bar or marker in the graph, the markers color-coded according to which pair of parallel room surfaces support the standing wave. For example, a red marker at the position in the graph representing 4dB and 180Hz, indicates that a standing wave will exist between the walls defining the width of your listening room when a 180Hz signal is produced by the loudspeakers, this standing wave having a relative sound pressure level of 4dB at the listening position. Ideally, you want all of the graph's markers to fall within the displayed dotted rectangle or target area. You can choose one of three target areas, each one representing a different degree of listening room "liveness". I chose the average target area setting since my room isn't overly live or dead.
The frequency response graph displays the relationship between absolute sound pressure level and frequency. You will want to manipulate the virtual listener and loudspeaker positions until this graph is as flat as possible, without any major broadband peaks or valleys.
Once all the attributes of my loudspeakers and listening room were defined,
I was ready to use Visual Ears to try to find optimal listener and speaker positions.
After about a half hour of doing the virtual cabinet waltz, I managed to come up with a pair of graphs for each loudspeaker
that were about as good as they were going to get, further changes tending to worsen
things rather than improve them. The resulting graphs for the Conquest and Studio 150 loudspeakers are shown in
figures 1 and 2 respectively, the standing wave graph appearing at the top of each figure,
the frequency response graph appearing at the bottom.
|Figure 1: Standing wave and frequency response graphs for Coincident Speaker Technology Conquest loudspeaker.||Figure 2: Standing wave and frequency response graphs for ProAc Studio 150 loudspeaker|
A couple of things are worth noting for the benefit of those of you who will lose sleep over failing to get all of the standing wave graph's markers to fall in the target area: no matter how hard you try or how loudly you curse Visual Ears, the red markers at around 40Hz and 140Hz will stubbornly refuse to move away from the bottom of the graph if the program is used in symmetrical mode. If you want any chance of moving all of the markers into the target area, then you're going to have to resort to an asymmetrical setup. Also, unless you have some means of adjusting the height of your loudspeakers or your listening chair, you won't be able to move the green markers at all, as their positions are only affected by changes in loudspeaker or listener height. A nice feature of Visual Ears lets you choose which markers will and will not be displayed on the standing wave graph. Since I couldn't practically adjust the height of either pair of floorstanding loudspeakers or my listening seat, I chose to use this feature to omit the green markers from the standing wave graphs in figures 1 and 2.
Something else to keep in mind when using Visual Ears is that the program is designed to optimize the quality of the sound that you hear at your listening seat, not the aesthetic appeal of your listening room. The program will sometimes recommend positions for your loudspeakers and your listening seat which you or your significant other will find either visually unacceptable, or physically impossible to accommodate. For example, the first good location I found for the Studio 150's had them standing very close to the stone fireplace in my listening room. Since I didn't feel like using the ProAc's as kindling, I played with Visual Ears a little longer and found a more appropriate but equally good location for the loudspeakers. The point here is that there is rarely only one set of good positions in your listening room - if one doesn't work for you, look for another.
As a result of reviewing the Conquest and Studio 150 elsewhere in this issue, I already knew of near-optimal placements for these loudspeakers in my listening room, these placements derived manually using a sound pressure meter and a test CD. Using this information, I had the ability to objectively gauge the accuracy of the positions computed by Visual Ears. Upon comparing the manually derived loudspeaker/listener positions with those computed by Visual Ears, I was quite surprised to find that they were very similar. In fact, the locations that Visual Ears predicted were within about six inches in each direction of those found the hard way! This was pretty impressive for an $89 software package. While the physical positions computed by Visual Ears were quite accurate, the frequency response graphs showed considerably more room gain below 50Hz than was borne out by my in-room measurements. Rather than a failing of the program, I suspect this is a reflection of the fact that a software package like Visual Ears can't possibly account for the break-up of standing waves caused by furnishings and other objects in the listening room. The lesson here is that the positions computed by Visual Ears will almost always give better results in-room than the graphs predict.
Will Visual Ears replace your sound pressure meter and test tone CD? Not entirely. While Visual Ears can compute good first approximations to the positions of your loudspeakers and listening seat, these positions will almost always need to be fine-tuned by a combination of listening and measuring. To find out more about using a sound pressure meter to help position your loudspeakers, see the article entitled Essential Accessories: The Radio Shack Sound Pressure Level Meter elsewhere in this issue.
If you're like me and you still enjoy listening to music on one of those "antique" devices called a turntable, then you can use Visual Ears to assist you in finding a low-frequency null in which to place it. To do this, simply switch to the program's asymmetrical mode, pretend that the virtual listener is the turntable and move it around the room until the graphs indicate a deep low frequency suckout at the turntable's position. I'm not sure why this application isn't mentioned in the otherwise excellent user's manual accompanying Visual Ears as it was discussed in the documentation accompanying The Listening Room.
Although the user interface of Visual Ears is better than that of The Listening Room, I did have a couple of minor nits to pick with it. The interface is not really consistent with the standard set by most other Windows 95/NT programs - no button is provided to minimize the application, and the program's icons are non-standard. In addition, while Visual Ears lets you save your results to files on disk, you cannot specify a directory for those files - they are always saved to the directory containing the Visual Ears program. Although these are fairly minor problems, correcting them would further improve this already excellent program
I was quite impressed with Visual Ears. It was
fast, easy to use, and allowed me to quickly and effortlessly locate good
listening room positions for two very different dynamic two-way loudspeakers. While
the program isn't for everyone, in particular, those with irregularly shaped listening
rooms or loudspeakers without dynamic drivers, it should serve the purposes of a large proportion of
the audiophile community. If the program does support your loudspeakers and listening
environment, I suggest you give it a try. At a price of $89, Visual Ears may be one of the cheapest and most useful
audio accessories you'll ever purchase.
Visual Ears was run on a Dell Dimension XPS Pro 200 (containing a 200Mhz Pentium Pro processor) with the following goodies: 32MB of memory, a 2.1GB Western Digital drive, a Dell/Trinitron 17" monitor, a Microsoft mouse and a sleeping-spouse-friendly QuietKey keyboard. Operating system was Microsoft Windows NT 4.0. Loudspeakers used were the Coincident Speaker Technology Conquest and the ProAc Studio 150.