Manufacturer's description:
'Made of high quality hand-spun aluminum, Jo-Ral bass trombone straight mutes are designed and tested to perform evenly in all registers. Finished with a brass bottom, this model offers a slightly warmer, almost dark sound compared with the standard all-aluminium model. The mutes feature neoprene-enhanced composite cork pads that grip well and don’t dry out, become brittle or break off, and so last longer while easily accommodating fine adjustments for a perfect fit.'
Straight mutes are by far the most widely used mutes for brass. They are cone-shaped with three narrow corks to hold them in the bell. Sound emerges from the gaps between the corks. Straight mutes generally reduce low frequencies and accentuate high, giving a more nasal, reedy sound. Aluminium straight mutes have a brighter sound than those made of softer materials like plastic, fibre or wood.
Also available:
TRB-4A Aluminium straight mute
TRB-4C Copper bottom straight mute