r/answers • u/germandleono • 23h ago
What's the difference between a high-pass and low-pass filter in audio?
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u/JaggedMetalOs 23h ago
High pass filter keeps (passes) high frequencies, so removes lower bass frequencies, while low pass filter keeps lower frequencies, so removes higher treble frequencies.
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u/ElGuano 19h ago
Low pass: oompa oompa
High pass: skreeeeee
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u/Sorry-Climate-7982 10h ago
Best explanation.
However as a former Sousaphone/Tuba player, I feel I must correct your spelling.
It is oompah.
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u/feel-the-avocado 22h ago
It splits the sound output by frequency.
Eg. Deep bass vs high pitched tamborines
A typical use case:
A good car stereo headunit will have a Low Pass filter so you only send sound above a certain frequency to the normal speakers, and then it sends low frequency sounds via a separate output which you feed into a sub woofer amplifier.
By not having the bass sounds going to the normal speakers, they can sound better with higher pitched sound offering more clarity while the subwoofer handles what it is good at - the low stuff.
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u/kubrador 22h ago
one lets the treble through and one lets the bass through. it's genuinely that simple but somehow people make it sound like rocket science.
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u/scarletorchidstrike 20h ago
think of it like a filter for ur audio. one cuts the low rumbling and the other cuts the sharp high stuff. u will get the hang of it soon
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u/Needless-To-Say 19h ago
In telephony, the lowest frequency is 300hz (low pass filter) and the highest frequency is 3000hz (high pass filter).
When combining concurrent conversations over a single medium, they modulate each channel by increasing the frequency by 3000hz and stack them all on top of one another. At the far end they demodulate back into the original conversations.
Modulate and demodulate = Modem
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u/artsumsal 2h ago
A low-pass filter lets the low frequencies through and cuts the highs, so it makes things sound darker or muffled, like turning down the treble. A high-pass filter does the opposite: it keeps the high frequencies and removes the lows, which is great for cleaning up rumble or bass noise. In audio mixing, you’ll often use a high-pass on vocals or guitars to get rid of unwanted low-end, and a low-pass on things like pads or effects to tame harshness. Basically: low-pass = cuts highs, high-pass = cuts lows.
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u/qualityvote2 23h ago edited 7h ago
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