Sound Lab Electrostats

Introduction First, an explanation will be given to explain why the SALLIE is necessary. This will be followed by a section on how to properly use the SALLIE. The SALLIE is an acronym that stands for: Sonic Attenuation for Lower Levels of Interference Effects.
The backwave energy emanating from the backside of a dipole speaker can cause undesirable sonic anomalies and, therefore, must be reduced to a level where they don’t detract from the sound presentation. The SALLIE backwave sonic attenuator is an acoustical device that virtually eliminates these problems by absorbing the exact degree of backwave energy necessary to eliminate audible room anomalies and restore pristine reproduction.
Specifically, dipole speakers radiate acoustical energy from both the front and rear sides. In many acoustical environments the rear energy reflects from the back and side walls and reaches the listener with a several millisecond delay with respect to the front wave. The time difference between the front wave and the complex of reflected energy (sometimes referred to as “time smear”) can confuse the ability of a person to localize reproduced sounds. This can result in a degraded perception of the sound stage. Furthermore, the two waves can interact, creating frequency-dependent additive (enhancement) modes and subtractive (depletion) modes. This usually results in a roughened frequency response referred to as the “comb-filter” effect.
The conventional approach of controlling backwave energy is to treat the walls behind and to the sides of the speakers with acoustically absorbent material and/or devices. The problem with this approach is that it can adversely affect the aesthetics of the room and may be relatively expensive. Furthermore, since this form of treatment is generally permanent it can make it difficult and inconvenient if one desires to change the amount of absorption or to change the location of the speakers. These disadvantages are eliminated with the use of the SALLIE since it is portable. Also, SALLIE is not visible to the listener and is comparatively inexpensive. Furthermore, SALLIE employs a double-layer of 6 inch long absorption wedges. This is dimensionally much larger than the absorbing depth of most other room treatments and is, therefore, more effective.

In summary, the major benefits of the SALLIE are:
1. The SALLIE reduces the backwave energy of dipole speakers to acceptable levels without destroying the “liveness” of the room.
2. The degree of attenuation is precisely adjustable simply by moving SALLIE toward or away from the back of a dipole speaker. This is important since rooms differ in their innate absorption due to having more or less furniture and varying In the degree of absorption of the floor, ceiling and walls. If the SALLIE is placed in the maximum attenuation position, the sound in some highly damped rooms can become overly damped. In such cases the proper degree of attenuation can be obtained by moving the SALLIE away from the speakers until the desired amount of damping is attained. On the other hand, if a room is overly “live” (reflective) SALLIE would be set closer to the speakers to absorb more energy. This is explained in the Installation section.
3. The double-layer of six inch wedges is effective from 250 Hz upwards.
4. The high level of performance of the SALLIE greatly reduces, if not eliminates, the need of back and side acoustical wall treatment.
The installation procedure is as simple as placing a SALLIE’s at the optimum distance behind each speaker. This distance, as mentioned previously, is determined subjectively. In summary, if the sound is too reflective and hard, move the SALLIE closer to the speaker. On the other hand, if the sound is too “dry” move the SALLIE further away from the speaker. The speakers should be about two to three feet away from the back wall to provide room for the SALLIEs.
For narrow aperture speakers (membrane speakers with a narrow tweeter section) the points of the wedges can be brought up nearly to the point of touching the speaker. This position will give maximum attenuation. The SALLIE will not color sound even when placed close to the back of the speaker.
Speakers with curved membranes should have the tips of the wedges placed at the point of curvature in order to obtain maximum attenuation. More specifically, speakers with curved membranes have a focal point (the virtual line- source) behind the speaker where the sound rays focus. This can actually be
heard by moving one’s head until it reaches the point of maximum sound level. If the sound is too dead from the listening position, move the SALLIE away from the speaker until it sounds correct. It is best to move SALLIE in approximately 6 inch increments or less. Figure 2 shows a side view of the SALLIE placed behind a speaker. Figure 3. shows a top view of a speaker and a SALLIE, and shows graphically what has just been explained.
Theory of Operation
Figure 1. shows a side view of the SALLIE. Note that the front wedges are offset by half of a wedge width from the rear wedges. This geometry provides a constant path length, D, through the attenuator regardless of the position along the wedges which the energy enters. Therefore, the portion of the backwave that penetrates the wedges will experience uniform attenuation over the length of the device. That portion of the energy that reflects off of the wedges will be trapped in the wedge structure and be absorbed in multiple reflection/absorption cycles. The six inch wedge length provides effective attenuation down to 250 Hz.
Energy that reflects off of the back wall and returns to the speaker must also encounter the SALLIE. This “return path” attenuation further reduces back wave interference effects. Figure 1: Side view of absorption wedges showing the modes of absorption.

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2 months ago | [YT] | 4

Sound Lab Electrostats

A TURNING POINT for SOUND LAB: PRE & POST 2006 - what you should know - notes for next video I'm planning.

In 2006 Roger at Sound Lab introduced what he termed 'PX' technology which effectively is one of the more significant turning points that brought Sound Lab out of what might described as infancy or formative years of technology. As usual Dr. West wrote a very informative paper of introduction with detail. But not all have time or patience to absorb the true details of the message. I have noticed also with the passing of years and/or the passing of panels to new owners, that many are not aware of the improvements and people simply accept that their older panels are the best that Sound Lab can offer, not knowing of the most significant advancements thru those early years. Sometimes just a photo can help because mostly people don't see behind the 'curtain'. This is misleading and unfortunate to assume that not much has changed behind the grille. I'm planning to address this in a brief video. Please find attached the original notice for reference. I have marked it up a little to note a few points that I intend to address. Also two photos to peak your interest (I hope).

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4 months ago | [YT] | 4

Sound Lab Electrostats

A great story that leads to an excellent chance to audition Sound Lab in Germany (quite close to Munich actually). The story is from Dietrich, the CTO and founder of Acoustical Systems (www.acoustical-systems.de/): manufacturer of ultimate analog front end turntable, tonearms etc. and was told in an email to Roger just last week. Photos attached are from his show/listening room: G8-7Cs (from 2011 and legacy model name is 845 Majestic) You will notice the model is just prior to our introduction of bass focus arrangement of distributed resonance ... paired with Acoustical System's incredible analog systems and wonderful room, I hope to make a visit to Germany soon and experience myself. This all happened a little too late for us to join Dietrich at Munich's audio show this year, but Dietrich is there - please go ask him about his story find Sound Lab - and schedule a listen if you have time!

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4 months ago | [YT] | 4

Sound Lab Electrostats

6 months ago | [YT] | 2

Sound Lab Electrostats

I have edited and improved explanation for video from last year. Sometimes difficult to know which clip is useful, if you are interested to see behind the grille and understand more about different model nomenclature, I'd like to recommend a look if you have not already. 
Cells of Sound Lab: G9-5C delivery - Explaining nomenclature 'Cells in width'
https://youtu.be/9SH9KEo-cqI

7 months ago | [YT] | 1

Sound Lab Electrostats

Please to announce Sound Lab with Dr. Vinyl will be at SWAF 2025 in Dallas: March 21st~23rd.
More details to come soon, however we are preparing a beautiful new G7-7C for Room 1201 (larger than normal room).

7 months ago | [YT] | 3