Why do engineers who make billion-dollar speakers still stay loyal to cheap materials that are often ridiculed?
Engineers who make billion-dollar speakers reveal: Why are they still loyal to cheap materials that are often ridiculed? The factors that determine the sound of a speaker are details that are never advertised. Even the reviewers who were most critical of this material unintentionally proved the engineers right. Let's make a comparison: Between a pair of bookshelf speakers made from standard reinforced MDF wood (the box price is about $87 to $129) and the $750,000 Magico M9 masterpiece is a price difference of up to 8,600 times. While the cheap speakers use MDF, the M9's shell is woven from high-quality carbon fiber. The speaker cabinet material is something customers can see and touch. That's why manufacturers always turn it into the most powerful marketing weapon. However, measurement data from laboratories and even technical documents of companies show a completely opposite hierarchy. Bracing, internal acoustic foam, wall thickness, and driver suspension each create much greater changes in resonance measurement than simply changing the case material.
When sound absorption and speaker frame bones defeat the shell material
If cabinet material is truly the deciding variable, then switching from MDF to solid aluminum should make the biggest change on the measurement charts. But in reality it doesn't happen like that. In a test, Tonestack compared three 19-liter speaker cabinets made from MDF, birch, and chipboard (OSB) of the same thickness. The results show that: Filling the inside with sound absorbing cotton is much more effective than changing the shell material. Acoustic cotton cut the internal resonant sound pressure by an average of 10 dB, regardless of the wood the case was made of. This test also explains why manufacturing techniques are superior to material labels. Tonestack estimates that a carefully calculated chassis system and internal geometry will reduce standing waves by an additional 6 to 10 dB, compared to an empty rectangular cabinet made from the same material. To put it simply: The speaker box will change more positively when the internal structure is controlled, instead of just spending money upgrading the outer wall from MDF to genuine plywood. Research by Hi-End brand Von Schweikert Audio also agrees with this point of view. Through the process of using lasers to measure vibration interference, the company found that using anti-vibration material to hang the speaker driver instead of screwing it directly to the wall of the box reduced resonance by more than 12 dB.
The fatal weakness of super-hard materials: Echo phenomenon
Rigidity prevents the speaker cabinet from bending under great pressure, but it does not automatically provide quietness. When super-hard materials such as aluminum or carbon fiber are excited to vibrate, they have very low intrinsic attenuation. As a result, energy accumulates and is released as a metallic echo. Magico also frankly admitted this physical phenomenon. To overcome metal resonance, the company must apply an extremely complex multi-layer damping technique to eliminate excess energy. Similarly, when Bowers & Wilkins decided to replace the Turbine Head assembly on the 800 Series from Marlan artificial stone material to a 17kg cast aluminum block, they had to inject layers of thermoplastic polymer inside to block all vibrations of this metal block.
Where is the real price of billions?
When we recognize the physical limitations of materials, we will understand why the price gap is so large. A raw MDF panel costs only a few dozen dollars, aluminum blocks are about 6 to 8 times more expensive. The difference in raw materials can never create a price gap of thousands of times. The huge cost of a pair of Hi-End speakers lies in the following stages: CNC milling, creating curved shapes, gluing, stuffing with sound-absorbing materials and assembling with tolerances in micrometers. For example, with Wilson Audio's proprietary Twitter-Material, the selling point is not because it is a unique material, but because the company has engineered it to only resonate at a very predictable frequency (about 1.2 kHz). Once the material's behavior can be controlled, engineers can design speaker cabinet structures to completely suppress that vibration.
The persistent existence of MDF wood in the Hi-End segment
Although often labeled as a cheap material, MDF is still the preferred choice of many top speaker brands when they need a large inertial mass and good self-damping ability. Typically, Focal with its high-end Sopra speaker line, they use massive MDF blocks to create compaction, then use vibration mapping software to find weak spots on the wall and precisely reinforce them there. Or like Von Schweikert Audio, after 2 years of laser measurements, they still decided to use resin-soaked MDF as the outer shell for their 3-layer box structure. In short, whether in the popular or super high-end segment, every pair of speakers faces the same physical problem: How to keep the walls of the box from emitting sound. Expensive materials like aluminum or carbon fiber provide superior physics, but they are no engineering miracles. The real factor that creates a deep bass range and a black soundstage lies in the skeleton structure, internal sound-absorbing materials and how engineers control the vibrations of the entire system. Source: headphonesty