Development

Ask anyone in the acoustic treatment industry what the single most prevalent issue is for the customer and they will tell you that it has to do with color. This includes the color of the delivered panel not matching the swatch due to die-lot variables, the customer not being happy with the color they chose once it is up on the wall, a committee not being able to make a color decision that pleases everyone, an architect not being satisfied with the standard colors being offered or a family member simply not being thrilled with the way the panels ‘clash’ with their home theater decor. With over 20 years in this business… you can be sure we have seen and heard every possible issue.

Primacoustic Paintables were developed as a solution by enabling the end user to decide upon the color after the panels have been delivered and installed. This eliminates uncertainties regarding the color selection and opens the door to the creative use of textures and finishes. Paintables do away with all of the aggravation involved by streamlining the whole panel selection process!

 

How difficult can it be to paint a panel?

Painting a panel is easy. The challenge, as we discovered, is painting the panel without affecting the acoustical performance. This required several redesigns until we finally came up with a formulation that works.

Acoustic panels are for the most part sound absorbers. This means that they are designed to allow acoustic energy to penetrate. Once inside, the energy causes the minute glass wool fibers to vibrate creating a thermal-dynamic transfer as sound turns into heat. The type, density and thickness of panel will determine the amount of absorption. Paintables employ the same 6lb glass wool construction as our popular Primacoustic Broadway panels. These have been tested to deliver exceptional absorption from the very highest frequencies down into the lower bass region.

If you merely slap a thick coat of paint on a regular acoustic panel, you will affect the acoustic performance. As the paint dries and hardens, the surface will reflect energy back into the room the same way that walls and glass do. The Paintables employs a specially formulated fiberglass mesh that has been carefully woven to allow energy to pass when painted. Carefully balancing the openness of the mesh and the thickness of the latex surface is the magic that makes it work.

 

Comparing Broadway and Paintables

Like the Broadway range, Paintables are made from high density 6lb glass wool. The difference here is that instead of being covered with micromesh and a polyester tweed fabric, the Paintables feature a tight fiberglass weave mesh that is factory painted in Absolute white latex. Both panels employ resin hardened edges.

The following graph compares the performance of the new Paintable with the Broadway 2″ panel. You will note that while the performance is almost identical, the Paintable absorbs slightly more energy in the voice range and slightly less in the upper register. This makes sense as the paint introduces a membrane which will have a slight reflective effect in the upper end while trapping slightly more bass.

 

Paintable vs. Broadway Acoustic Panels

Comparison of Paintables 2″ w/latex and Broadway 2″ panels

 

The effect of adding paint

What makes the Paintables so exciting is that they can be painted. Being able to apply any color you want means that you can now properly match a room decor or meet an architect’s demands. Because these panels are pre-painted in white latex, you are starting with a panel that has a primer coat. This means that you can coat the panel with any type of paint or leave it ‘as is’ if white works in your room.

The best results are obtained by spraying the panels with a fine mist. This creates a very thin layer on top of the latex which will not interfere with the acoustic properties. The following graph compares a Paintable with one that has been coated using a fine spray. As clearly evident in the graph below, the acoustic performance of the panel has hardly changed at all.

Paintable Acoustic Panels Latex vs. Light Spray

 

This image shows actual panels that were painted before being sent to Riverbank labs for testing. A dusting of spray paint will not affect the acoustic performance. Adding a thicker coat of paint will retain more of the upper frequencies. This can be beneficial in certain installations such as larger rooms or in home theaters where retaining energy and excitement is important.

Paintable Options for Acoustic Panels

 

Voicing the panel to suit

Where things get interesting is how you can actually ‘voice’ the Paintables by increasing the thickness of the paint. For instance, you may want to retain a greater sense of air or high frequency content in a recording studio for more of a live feel. Another example could be an orchestra pit or stage where you may want more reflection in the upper region to enable the musicians to better hear themselves. For instance, choirs usually prefer singing when they can hear some ambiance or their voices bouncing back towards them.

The following graph shows how increasing the thickness of the paint will affect the performance. The red line shows how adding a very thick coat of latex using a roller can dramatically reduce the high frequency absorption. Yet as the thickness of the membrane is increased, it also improves low-frequency bass absorption.

Paintable Panel Effectiveness

 

Focusing on the voice range

The primary reason to apply acoustic panels to a wall surface is to improve intelligibility. Intelligibility is the term we use to describe our ability to comprehend what is being said or the message being transmitted. In a telephone call center, acoustic panels are used to eliminate the ambient noise from all of the callers making it easier to hear what people are saying over the phone. In video conferencing suites, eliminating the echo in the room vastly improves communication just as it has been done in radio broadcast for nearly a century. In a house of worship, eliminating the echo makes it possible to finally hear the sermon. The object is to eliminate unwanted clutter, echo and noise in the voice range.

The energy in the human voice is centered at 500Hz, starting from around 250Hz and rising to about 3kHz, with most of the energy centered between 300Hz and 1500Hz. This is the sweet spot. As you raise your voice, the energy becomes all the more focussed in the mid band. Paintable panels are particularly effective in this region with 70% to 110% absorption at the critical 500Hz center point, depending on the thickness of paint being applied.

Paintable Acoustic Panel Effectiveness

 

The right panel for the right application

Paintables are designed for spaces of all sizes including houses of worship, restaurants, libraries, museums, airports, offices, boardrooms, call centers and video conferencing suites. In fact any room that needs treatment will enjoy significant improvement by mounting Paintable panels to the wall surface. These are mounted using a choice of impalers.

Paintables are intended for installations where the panels will not be leaned against or rubbed. Paintables are not intended for use in heavy traffic areas such as busy hallways where people will lean on them, music teaching rooms where instruments can hit them, gymnasiums where balls will destroy them or other installations where they can be abused. Broadway panels are much better suited in these cases due to their rugged polyester tweed covering. If you want to use a Paintable in a high abuse area, you can protect the panel by adding Primacoustic End Zone cages over top each one. Just applying some good old fashioned common sense before recommending them!

Prescribing the amount of wall coverage There are no set rules when it comes to acoustic coverage. Some prefer rooms to retain air or a sense of space by allowing some energy to reflect back into the room. This is particularly important in home theaters where an overly treated room will sound dark and lack energy. In recording studios or voice-over booths, the percentage of absorption is typically increased.

The following are ‘rules of thumb’ when it comes to applying treatment to the walls.

 
Broadcast studio Video conference House of worship Call Center Restaurant Home Theatre Band shell
Maximum 40% Maximum 35% Moderate 25% Moderate 25% Moderate 25% Minimal 20% Minimal 20%
 

Start by adding up the reflective surfaces and suggest 20% to 25% coverage. This will give the client a budgetary number for the panels. Most rooms will enjoy dramatic improvement starting at 20%. You can then discuss the installation and where to best locate the panels to eliminate primary reflections. From there, adding or subtracting panels will either darken or lighten the sound of the room. In large rooms such as a house of worship, the main goal is to control the mid-range where the voice is centered. It is also important to note that in large rooms, high frequency energy quickly dissipates so it is nowhere near as problematic as it would be in smaller rooms such as home theatres or restaurants. Mounting Paintables is done using Primacoustic Impalers. Care is of course needed when installing as Paintables are more delicate than Broadway panels.

Testing, 1, 2, 3…

Primacoustic Paintable panels have already been tested by Intertech to meet flame spread and smoke development for safe use in Canada and the USA and are classified as class-1/A following the ASTM-E84 and CAN/UL-S102 criteria. They are also currently being tested at Intertech for use in the European Community. We hope to have the results from these tests in hand shortly. The panels had acoustical tests performed at Riverbank Labs in Chicago which is where the test data in the graphs above has been derived.

Testing is expensive, yet very important as this provides accurate data on how the Paintable panels work and the data enables engineers to derive more information by postulating the variables to come up with fairly accurate predictions. Companies that do not publish independent reports should be suspect.

Primacoustic Paintables bring forth a high performance acoustic panel that can be painted on site to match the room decor without diminishing the acoustical performance. This makes them a wonderful choice for just about any acoustical installation.