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https://issues.apache.org/jira/browse/AVRO-3220?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Tzvetanov Grigorov resolved AVRO-3220.
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Fix Version/s: (was: 1.10.2)
Resolution: Not A Bug
> How Many Decibels Are My Headphones?
> ------------------------------------
>
> Key: AVRO-3220
> URL: https://issues.apache.org/jira/browse/AVRO-3220
> Project: Apache Avro
> Issue Type: New Feature
> Components: build
> Affects Versions: 1.7.2
> Environment: I'm assuming you're checking the decibel levels of the
> music you're listening to with headphones to see if they're safe to listen to
> while driving or exercising. Also, I'm assuming these headphones have
> over-the-ear earcups. I'll modify my response to fit these criteria, but the
> setup described below can be used with minor modifications for other types of
> headphones and tests. Headphones that fit over the ear will require no
> adjustments. Anything that holds earbuds will have to be similar in shape to
> an enclosed ear canal.
> click here :
> [https://hereplus.me/how-many-decibels-are-my-headphones/|https://hereplus.me/how-many-decibels-are-my-headphones/]
> Frequency response measurements can also be performed with this set-up, but
> the accuracy degrades quickly. In other words, the more realistic your model
> looks in your head, the more accurate your measurements will be.
> To make binaural recordings, you'll need to buy a dummy head and mount a
> microphone in each ear afterwards. These are the most realistic spatial
> recodings you'll hear through headphones if you do this. However, let's
> return to the dB meter.
> A dB meter is first and foremost required. These can be purchased for less
> than $50 on the internet or at a music or electronic supply store. They are
> also readily available. If there's a Radio Shack near you, they have a wide
> range of models. You can use your smartphone if this is a one-time
> measurement. There are numerous free dB metering apps to choose from. It's
> fine to use an app if you're just curious and don't need a lot of precision.
> Read reviews before ordering a meter online to avoid purchasing a dud.
> If you're unsure about the accuracy of a dB app, test it out with some
> familiar sounds. A library, traffic, and conversations all have dB levels
> that are easily found on the internet. To get an idea of how loud a room is,
> take the decibel level and divide it by the number of people present.
> Anything that exceeds a decibel level of 140 will cause immediate harm. When
> exposed for an extended period of time, lower levels can do you harm. After
> about 10 seconds of exposure to 120dB, your ears will be damaged. After about
> 10 minutes, the noise level of 100 decibels becomes harmful. Keep your ears
> to yourself. As long as you limit your exposure to loud noises, you'll be
> able to use headphones and have enjoyable conversations for years to come.
> Use a meter or app that is "C" weighted, regardless of what you use. A and C
> are the most commonly used dB metering weightings. Other weightings exist,
> but they're reserved for specialized applications, so you won't see them very
> often. "A" weighting, in my opinion, is ineffective because it only includes
> roughly the speech frequencies, severely excluding the low ones. It's used
> for determining whether or not a product meets federal safety standards for
> noise emissions. Other than covering your butt legally, I don't see any
> real-world application for it. Extremely loud sounds, regardless of
> frequency, are harmful to the ears. You should include all the audible
> frequencies in your measurement of how loud a sound is, not just the middle
> ones, if you want a reference measurement from headphones. The weighting "C"
> is the other alternative. The frequency range covered by C is extremely
> broad. All measurements should be done with a C weighting.
> You'll also require something cheap to place the headphones against so that
> you can record all of the sound output and use that for your analysis. It has
> to be larger than the earcups on your headphones in terms of both size and
> shape. If you want to go all out, a stryrofoam dummy head from a craft store
> like Michaels costs less than $10. You could use a styrofoam ball that's the
> same size and shape, but you'll have to flatten the ear area to make it fit
> your head. If your earcups fit snugly on it, a styrofoam board will do.
> To use a styrofoam board, simply place the earcup on top of the board and
> press down. Your phone or meter's microphone end should fit snugly through a
> small cutout in the board so that you can accurately measure the distance.
> Fill in any gaps around your meter or phone with scraps from your cutting
> project. Don't bury the display if you want to be able to read the results
> from the other side. Again, the most important thing to remember is to keep
> the area around the meter or phone as quiet as possible to avoid having
> inaccurate readings. When you wear headphones, sound is contained within a
> small enclosure on your head. When you put on headphones while wearing
> sunglasses, the sound will be muffled.
> The Styrofoam board must be thick enough to prevent vibration and sound
> energy transmission away from your measurement. If you use thicker stryofoam,
> you can keep your meter or phone's microphone end from sticking through the
> cutout hole and away from the speaker in the headphone earcup so that you
> don't damage the speaker. In order to avoid frequency irregularities that may
> be picked up from different spots on the speaker's surface if the microphone
> is too close, it may be beneficial to keep some distance between the
> microphone and the speaker.
> Styrofoam is a good material for your test set up because it absorbs little
> sound and can be easily cut. If you'd rather use wood, plastic, or heavy
> cardboard, those materials will work as well. Avoid using anything that
> absorbs sound, such as cloth. A lot of the styrofoam from packaging cartons
> can be used instead of being thrown away. The idea is to give the earcups a
> head-like, or at the very least flat, shape so that no sound escapes. Here's
> where you have room to express yourself.
> Cut a hole in the ear canal area and a meter cutout on the side of a dummy
> head if you're looking for utmost accuracy. As long as the dB meter does not
> interfere with the earcups, you can place it on any convenient side. Any air
> gaps around the dB meter or the earpads should be sealed off to prevent sound
> from leaking into the room. It isn't possible to duplicate the sound path to
> your eardrum because your ear canal doesn't have any such gaps. That's all
> there is to it.
> As soon as your cutout is partially in, make sure you can read the meter or
> phone display. Instead of inserting the entire meter, just the microphone
> portion will go in. The rest of the meter will remain out in the open. If
> your touchscreen or buttons aren't touching, you'll want to exercise caution
> when using the phone.
> Make sure you're listening to music at a volume you're comfortable with
> before you begin. Then, without touching the volume controls on your
> headphones, remove them from your head and set them on your test head or test
> plate. Take a look at what you've read!
> Reporter: Nguyen Tuan Hung
> Priority: Trivial
>
> h1. How Many Decibels Are My Headphones?
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