A bell suppresses high partials by radiation loss, not boosting them

Evidence

At 4000 Hz and even 2500 Hz, sound radiation is now dominating over friction, putting the situation on the waning side of the advantage curve. Increasing the transmission amplitude loss to 90% with a bell installed will only reduce the loudness of partials at 2500 Hz and above. The bell thankfully kills the annoying higher partials that you hear in a cutoff tube when it is played like a trumpet. They are diminished because of excessive sound radiation and failure to build intensity through the mechanism of resonance. This crucial detail seems to be omitted from the classic treble boost discourses. — Eric J. Heller, Why You Hear What You Hear- An…, 1518

Categorization

Category: Contrarian or Surprising Claims

Related

• Removing a trumpet bell empirically strengthens the high partials above 1500Hz (similarity 0.90)
• The accepted textbook claim of bell treble boost fails once loudness differences are normalized (similarity 0.88)
• Treble boost from trumpet bells may not actually make high frequencies louder (similarity 0.87)
• A trumpet without a bell has stronger high partials than with one (similarity 0.87)
• The simple bell-boosts-treble explanation of trumpet tone is incomplete. (similarity 0.86)
• A bell lowers a tube’s cutoff frequency, easing high-frequency escape (similarity 0.85)
• The bell reflects low frequencies deep inside and high ones near its rim (similarity 0.84)
• Wall friction and resonance oppose each other in determining instrument sound radiation. (similarity 0.82)
• A trumpet’s bell beams high frequencies forward, changing timbre with direction of aim. (similarity 0.82)
• A speaking-trumpet flare can boost lower frequencies when wall dissipation dominates resonance enhancement. (similarity 0.80)
• Brass instrument bells reflect low frequencies early and pass high ones. (similarity 0.80)
• The bell acts as a frequency-dependent reflector that shifts brass mode frequencies. (similarity 0.80)
• A bell’s perceived pitch is usually absent from its actual partials (similarity 0.79)
• Most acoustics texts attribute trumpet brilliance to treble boost (similarity 0.79)

Broader Connections

• A trumpet without a bell has stronger high partials than with one #expands (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 1530