Recent content by Don Hills

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    How Deep Must the Bass Be?

    A "tapped horn" is not a horn. It's a quarter-wave resonator, like an organ pipe. The "tap" causes it to have two resonances, one an octave above the other, thus widening the usable frequency range.
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    A Call For Humor!

    My daughter (cosmologist) was amused, in a facepalm way, by an obvious error in the graph and by assumptions in the paper it was sourced from...
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    Old amp crackling noise problem when turned on

    Before turning it on, try rotating the gain controls back and forth a few times. (Or while it's crackling.) The resistive tracks get noisy with age, and generate noise when DC current passes through them. The current is caused by the coupling capacitors charging up, and ceases once they are charged.
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    Is this absolute nonsense? Streamers degrade audio

    It's the same for ears, there are muscles that tighten at high sound levels and reduce the movement of the bones coupling sound from eardrum to inner ear. They protect you from deafening yourself when you shout. :)
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    Why are single drivers disliked to such an extent by most in this forum?

    There's the Altec Biflex drivers 419-8B and 420A. They have a secondary surround part way up the cone, forming a mechanical crossover at about 1 kHz. They were used in Altec Santana and Madrid speakers with a small cone tweeter crossed over at 5 or 6 kHz...
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    A Call For Humor!

    Dewey, Cheatem & Howe. The law firm in the PC game "Leisure Suit Larry."
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    Can Subs also act as AVAAs?

    I see a problem using the same subs for both sound generation and resonance cancelling. The ideal position for a "music" sub is where it minimises excitation of resonances. The ideal position for an active cancellation sub is where it maximises excitation of resonances and thus is most effective...
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    Can Subs also act as AVAAs?

    Most on/over ear ANC headphones have the canceling microphone on the inside, as close as possible to the ear canal. They compare the signal from the microphone with the incoming audio signal. Any difference generates a compensating signal to the earphone driver. Negative feedback... Some...
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    Why are XLR cables only locked on one side?

    The "hot pluggability" of XLR cables is because the ground pin is longer than the signal pins so breaks contact last. RCA plugs are the opposite, where the ground connection breaks first, injecting any voltage difference between the connected devices into the signal path.
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    Can I use a 12-inch woofer as a resistor to set amplifier gain?

    Light bulb resistance varies tremendously with temperature. Speaker resistance / impedance varies tremendously with frequency. One or two high power resistors looks like the most cost effective way to get 4 ohms. Remember they don't have to be rated for the full 250 watts, for what you're...
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    Why do records sound so much better than digital?

    Given your preferred technology you appear to be referring to pre-echo, which of course is real and audible. I can understand your being bothered by things that you know are there but can't hear. Years ago when someone would argue that records sounded better than CDs I would play a 1 KHz tone...
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    Why do album mixers use limiters to crush dynamics?

    There's about the same proportion of metalheads that appreciate high fidelity in their chosen genre as there are in other genres. You know something's wrong when a heavy metal album ends up less compressed than a semi-acoustic soul/blues album. (Iron Maiden, "The Final Frontier" versus Tom...
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    Demagnetizing CDs?! (more Techmoan fun)

    Just demagnetise the marker pen. Saves you the bother of demagnetising each CD.
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    Can anyone explain the vinyl renaissance?

    I believe the technical reason for the high power amps is because the cutter head (like a tape record head) is current driven. Like a tape head, its impedance rises as the frequency increases. The amplifier has to have enough output voltage swing to drive enough current through the head at high...
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    Open baffle bass leakage

    As others have said, when you have a real world driver that has finite diameter, things get complicated. You no longer have one length from front to back. You have a range, from near edge to near edge through to the distance from far edge to far edge. For a 10 inch driver on a 20 inch diameter...
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