High air velocities in a Karlson 12 distributed slit vent exhausts candle

70Hz sine tone progressively increased in level. IMO higher than a lumped vent of the same area and probably detrimental to supporting sine-wave below cutoff (and Fb). On the up-side it may be good for subjective transient response. There wasn't a horrendous amount of overtones at these power levels - the camera's mic overloaded. I know from listening and from RTA-oscilloscope the small area/dimension distributive vents seem to pump up air velocity. Use of distributed port or vent was popular in the 1950's. I doubt if the cone excursion to blow out the candle was more than 1/64" peak to peak. Standing up and listening above the cabinet, the tone is weakened (and possessing harmonics) and about 1 note lower on a scale than getting closer to the floor.

70Hz sine-wave - small signal Fb is close to that frequency

Category:

Science & Technology

Tags:

• Karlson speaker
• bass reflex
• speaker vent
• speaker excursion
• Karlson coupler
• vortex

[radcam69]

what kind of driver is that?

[gnativerson]

@radcam69 -that was the Pyle/Eminence PYM1298 listed as having a 95oz magnet slug - I'd assume the new Kappa 12A is pretty close. That coupler with PYM1298 and a slotted Karlson waveguide on top had better drum transients than my fake La Scala set ( Peavey FH1/ Altec 511-K55V and APT150)

[CherylJosie]

The change in pitch has nothing to do with the cabinet or the port configuration. It is an artifact of human hearing.

[CherylJosie]

"Standing up and listening above the cabinet, the tone is weakened (and possessing harmonics) and about 1 note lower on a scale than getting closer to the floor."

Subjectively the human auditory cortex is known to perceive any frequency at a higher pitch when the sound pressure level increases. Just listen to anything at 100dB and then cut the level to 40dB and you will instantly perceive that the pitch drops a semitone along with the amplitude drop even though there is no change in frequency.