SoundBlox® get their excellent sound absorption from a unique cavity-slot resonator construction. The funnel-shaped slots of the RSR, RSC and Q Type units provide superior acoustical performance.

Using a metal septum and fibrous filler in the cavity works to provide higher levels of sound absorption across a wider range of frequencies.

The A1 is designed for low frequency absorption and the RC/RF is for walls requiring vertical reinforcing, insulation or cores for conduit and pipes. Whether they are painted, produced with colored pigments or left in their original state, the SoundBlox® unit is an excellent choice for noise reduction and acoustical performance.

See “Downloads” for further information on available shapes, sizes and related acoustical performance.

Available in all colored architectural finishes except split face.

Technical Data


Submit product literature, certifications, test reports, and full size sample(s).

Quality Assurance
All sound absorbing masonry units shall be SoundBlox® units made on standard block machines using molds furnished or approved by The Proudfoot Co., Inc. to assure uniform quality. They shall be made of carefully prepared aggregate and shall meet the current ASTM C90 or ASTM C129, and ASTM E119 requirements as appropriate. Soundblox® slots shall meet the following specifications:

A-1                    1/4” wide, straight through
R, RSC, RF     3/4” wide, flared
Q                       1/4” wide, flared, .28 ga. galv. steel septum

SoundBlox® types R, RSC, RSR, RF call for filler elements of specially fabricated incombustible fibrous material having metal septa laminated to one side installed with septa facing away from the slots. Type Q 8” units shall have only a bare metal septum.

Fire Resistance: Define hourly ratings required as 1, 2, 3, or 4 hours.

Field Constructed Mock-ups: Construct a sample panel, no less than 4’ x 4’, of units of each color and size to be used in the project.

Delivery, Storage And Handling
SoundBlox® units shall be delivered to the job site on pallets. Store pallets in single stacks on level ground and cover with water proof covering (e.g., tarpaulins) to protect the blocks from inclement weather. Handle blocks carefully to avoid breakage and damage to the finished surfaces.

Project/Site Conditions
Protection of Work: Cover walls each day after installation to keep open walls protected and dry.


Product Name
SoundBlox® sound absorbing structural masonry units.

York Building Products Company, Inc., 950 Smile Way, York, PA 17404 • 800-673-2408 • 717-848-2831 • FAX 717-854-9156, operating under license from The Proudfoot Co., Inc., Monroe, CT.

Sizes And Types
SoundBlox® units shall be 8” x 16” nominal face size. Sound absorption shall be in accordance with ASTM C423 with regard to type, size, hertz, coefficient, and NRC. SoundBlox® types:
A-1—4”, 6”, 8”                RF—8”, 10”, 12”
R—4”, 6”, 8”, 12”           RR—8”
Q—8”                               RSC—4”, 6”, 8”, 12”

Installation Guide

SoundBlox® units shall be installed by the masonry or general contractor. Only quality units shall be installed, discarding any units broken, chipped or cracked. They shall be laid in a full horizontal bed of mortar with the closed tops up. Slots shall be exposed to the area where sound absorption is required in accordance with the building plans. Care shall be taken to ensure that the slots are kept free of mortar or debris. SoundBlox® workmanship shall conform to all requirements of the general specifications for masonry work and shall be installed using the best masonry practices.

Make all unit cuts, inclusive of those for bonding holes, etc., with a motor driven masonry saw using either an abrasive or diamond blade. Align units, level, plumb and true with uniform, carefully tooled 3/8" wide joints. Raked joints are not recommended for any application. Block should be drawn from more than one pallet at a time during installation.

SoundBlox® units may be painted without significant reduction of sound absorption. Walls of SoundBlox® units made of porous aggregates must be heavily painted with cement base or other sealing type paint on the unslotted side to prevent porous sound transmission where maximum sound transmission loss is desired.

Install flashing at locations shown in the plans and in strict accordance with the details and the best masonry flashing practices.

Keep walls clean daily during installation using brushes, rags and the burlap squares supplied in the pallets. Do not allow excess mortar lumps or smears to harden on the finished surfaces. Remove green mortar with burlap or a dry cloth. Harsh cleaning methods after wall have been erected will mar the surface of the blocks.

Final Cleandown
Clean the completed walls with a detergent masonry cleaner strictly following the manufacturer's instructions including thorough rinsing. Do not use acid or abrasives on the finished surfaces.

SoundBlox® units, properly installed and cleaned, need virtually no maintenance other than with standard commercial grade cleaning agents such as Pinesol® or Lestoil®. Graffiti, paint or dye stains may need special cleaning methods and products. Contact manufacturer for special recommendations.


  • Always test a small inconspicuous area before using cleaners.
  • Matching mortar colors are recommended for architectural masonry units.
  • Do not use acids or abrasives on finished surfaces.
  • Use motor driven masonry saws with abrasive or diamond blades for cutting all concrete masonry units.