Engineered for hotels, high-end apartments, and commercial projects seeking certified acoustic damping and premium security integration.
Zhejiang Larsom Door Co., Ltd. stands as a premier global manufacturer, specializing in the intensive research, development, and advanced engineering of high-performance acoustic doors, armored security structures, and bespoke entrance solutions. Our commitment is anchored in delivering architectural components that marry world-class acoustic attenuation (STC/Rw) with structural security, complying with the most rigorous global commercial codes.
Spanning a state-of-the-art manufacturing campus of over 16,000 square meters and powered by a highly specialized workforce of 160+ industry professionals, Larsom integrates high-end CAD/CAM engineering with automated fabrication. This robust infrastructure guarantees a consistent output capability exceeding 200 customized sets daily, ensuring precision delivery timelines for tier-one global development projects, large-scale hospitality tenders, and industrial procurements alike.
Uncompromising sound attenuation built upon structural density, viscoelastic absorption layers, and proprietary seal design.
In modern architectural design, controlling flanking noise and airborne sound transmission is paramount. Acoustic doors are measured using the Sound Transmission Class (STC) under ASTM E90/E413 standards in North America, and the weighted sound reduction index (Rw) under ISO 10140-2 standards globally. While standard residential hollow-core doors provide a meager STC of 20 to 25, Larsom's high-performance assemblies achieve ratings from STC 35 up to STC 45+.
To achieve these high ratings, our engineering team utilizes the law of mass, structural decoupling, and resonance control. Simply increasing a door's thickness is insufficient; sound energy readily passes through rigid monolithic structures at specific frequencies. Larsom's acoustic assemblies use a multi-density core composition, combining hard wood species, high-performance WPC composites, acoustic mineral wool, and viscoelastic damping membranes that convert sound energy into microscopic thermal energy.
An acoustic door operates as a complete system. The door leaf, frame, perimeter gaskets, and bottom seals must work together to prevent sound leaks. A mere 1% gap in the door perimeter can compromise its performance, reducing a high-end STC 40 door to a rating below STC 30. Our systems incorporate:
Larsom's manufacturing processes focus on dimensional stability. Every door frame is engineered to within tolerances of ±0.5mm, ensuring that the door leaf seals tightly against the gaskets. This level of precision prevents warping, maintaining long-term acoustic performance even in high-traffic commercial environments like hotels and business offices.
Every production step is optimized using automated machinery and strict quality control protocols.
Larsom Door's industrial footprint leverages cutting-edge technology to achieve structural performance. Our factory utilizes high-speed CNC fiber lasers to guarantee perfect geometry for frames and armoured steel sheets. Standard mechanical splicing is replaced with automated hydraulic hot-press laminations, ensuring the acoustic core composite remains completely bonded and free of internal air gaps. Edge sanding is fully automated to provide a smooth base for veneers or laminates, and our UV production line applies protective coatings that resist moisture, impact, and wear.
Zhejiang is one of the world's most concentrated manufacturing hubs for structural and decorative door solutions. Larsom Door leverages this vertical integration to offer high-quality products at competitive prices, providing direct supply chain benefits to global buyers.
Our raw materials—ranging from high-density timber veneers to engineered polymers (WPC) and industrial cold-rolled steel—are sourced within a 150km radius. This localized supply chain reduces internal logistics costs, limits production bottlenecks, and allows us to pass these cost efficiencies directly to our international clients.
We work with building contractors, real estate developers, and international wholesale distributors, offering flexible OEM/ODM integration, custom dimensional configurations, and specialized protective packaging designed for maritime transport.
Tested solutions designed for regulatory approval and architectural specifications globally.
Different building types face unique acoustic challenges. Larsom customizes our door cores, seals, and hardware prep to meet these specific needs:
We ensure our products meet local building regulations across diverse export markets:
Technical answers to help architects, contractors, and procurement managers make informed decisions.
STC (Sound Transmission Class) is the standard measurement utilized in North America, calculated across a frequency range of 125Hz to 4000Hz under ASTM E413. Rw (Weighted Sound Reduction Index) is the international standard defined by ISO 717-1, measuring performance from 100Hz to 3150Hz. While they are calculated slightly differently, their numerical values are typically close. An STC 40 rating is equivalent to an Rw 40 rating for most building applications.
Yes, Larsom specializes in multi-performance engineering. Our steel-armored and solid-core wood doors can combine fire resistance (UL 10C or BS EN EI30/EI60/EI90) with high acoustic insulation (STC 38-42) and bulletproof steel plate reinforcements, providing integrated security, fire safety, and soundproofing in a single door assembly.
The automatic bottom drop seal is a spring-loaded mechanical system housed inside a channel at the bottom of the door leaf. When the door is open, the seal remains retracted within the door, protecting it from wear. When the door closes, a plunger contacts the frame jamb, triggering the seal to drop down and close the gap against the floor. This mechanical seal is essential for maintaining the door's overall acoustic rating.
For custom commercial projects, our MOQ typically starts at 20 sets, though we can accommodate smaller quantities for specialized orders. Standard lead times range from 25 to 35 days from technical drawing approval and deposit receipt, depending on the complexity of the materials and hardware specifications.
Yes. Acoustic doors must be installed as a complete, pre-hung system to ensure their performance. We supply matching engineered wooden or steel frames, acoustic gaskets, heavy-duty hinges designed to carry the weight of dense cores, and certified multi-point locking hardware.
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