Warren, I think the noise from the extra projection comes from the distance to the chipbreaker being less. The noise comes from air compressing and decompressing as the knives pass the chipbreaker, similar to tires. Tire companies recognized this and that is why truck tires are so much quieter now. I experimented on an old Delta I had moving the chipbreaker in really close to the knives and it sounded like a siren. With the Tersa's unique gullet design there is very little air trapped and I suspect that is where the quiet comes from.