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dB??
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astro_traveller
IsraTrance Junior Member
Started Topics :
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Posted : Jan 12, 2013 05:38:44
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So my question is how to use Decibels practically.
First thing lets say speakers dynamic range is 124 dB.. does that mean i can not mix on 24bit.. Coz 24 bits is 144dB. Lets say what is the relation between dB spl and dynamic range.
if my whoofers dB is more than my high speaker, do i need to use the compressor on the whoofer to make both equal dynamic range? And how to calculate the dynamic range to compress. How the compressor's dB and actual dynamic range are related.
If my speaker is using 10% of the power. Does that mean the dynamic range is reduced?
what IS 0 dB on a DAW? Wats the relation of 0 dB in 16 bits and 24 bits or lets say 64 bits?
what is the relation between dBu and dBv with 0 dB on a daw. Wat is -10dBu and +4dBv switch on my sound card? What it is doing technically when i switch?
what is the recommended dB spl on the mixing engineers position.
Is there any way to measure db Spl using a daw. with out using external SPL meter?
Lets say the dynamic range of my lap top speaker is 80 dB why doesnt it distort when i play dvd.. which is suppose to be 144 dB.
Im quiet confused with all these types of decibels. I been reading few things on decibels.. more i read more it makes me confused.
If some one can explain here it would be very nice.. or if u could post some good link which would answer my questions.
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TimeTraveller
IsraTrance Full Member
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3207
Posted : Jan 12, 2013 09:17
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lots of cool questions. I need to sleep but can say one thing 24bit or a range of 144db indeed is sometimes essential, not that it is maybe better but really essential. A trumpet reaches such loud peaks for example. Using 16 bit such recording would end up in a sqaure etc.
 https://soundcloud.com/shivagarden |
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Babaluma
IsraTrance Junior Member
Started Topics :
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Posted : Jan 12, 2013 13:59
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You're obviously confusing a lot of inter-related things, so I'd suggest a while researching Wikipedia and Google on things like "dB", "gain staging", "audio levels", "audio range compression", "dynamic range", "crest factor", "balanced vs. unbalanced" etc.
The dB info in speaker specs relates to the loudness at a set distance usually measured at 1 metre with a known reference input.
Although 24 bit is THEORETICALLY capable of 144dB of dynamic range, you'll rarely get more than about 110dB in real life situations. Then most people these days like to squash the dynamic range to about only 6dB for final distribution (effectively making them 1 or 2 bit recordings), making it entirely academic, but don't get me started on that. 
Not sure about the relation between dB SPL (how loud something is in the room), and dynamic range. Can you phrase the question better?
Not sure what you mean about your woofer being more dB than your tweeter. Woofers usually get more watts provided to them in active designs, because bass frequencies need more power to sound at equal perceived loudness to higher frequencies. (Note: Research "Equal Loudness Contours" for extra brownie points!)
Compressors/Limiters on individual speaker drivers is usually reserved for sound reinforcement/PA systems, and not something you need to worry about in so called "production".
If your speaker (am assuming ACTIVE here, in which case you mean the amps built in to the speaker?) is only using 10% of its power, then it's probably playing back music at a lower level. This has nothing really to do with dynamic range, except for the fact that it has 90% of its "power" in reserve for when loud bits/transients come.
0dB on a DAW is the maximum possible level that a digital word can represent. Go any higher, and you will get clipping (unless you're working in floating point, but that's a story for another time...) The difference between 8, 16, 24 and 32 bit say, is in the LSB (least significant bit), not the MSB (most significant bit), meaning that longer word lengths can represent quieter sounds better, before quantisation distortion occurs.
dBU, dBv, dBVU, dBLUfs etc. are all things a quick Google search will help with. -10dBu is a consumer audio standard level, +4dBv is a professional standard level. You'll need to research the manuals of all your gear, and do listening tests, in order to find the best match between different pieces of gear.
The recommended dBSPL at the mixing level depends upon personal preference, just be aware that listening for extended periods over 85dBSPL (C weighted, slow response), can lead to hearing damage. You should get used to listening to commercially mastered music at a lower position on your monitor gain control, and a much higher position when you are mixing, so that they play back at the approximate same percieved level. My whole chain is calibrated so that a -20dBfs pink noise is 77dB SPL is -14dBfs is 0dBVU etc. etc. Once you have calibrated monitor gain, and stick to it, it becomes much easier to decide about levels, when you are compressing/limiting too much etc.
The only way to measure SPL (sound pressure level) is with an SPL meter. They are pretty cheap, or try to rent/borrow one.
The measurements on audio/hi fi/music gear are all taken under certain strict conditions, which are sometimes stated, sometimes not. Just cos your laptop speakers have a dynamic range of 80dB, and the 48/24 audio on your DVD has 144, doesn't mean that playing a DVD on your laptop will distort them. Films can have a VERY wide dynamic range, but it's still not usually more than about 20-30dB between the loudest and quietest parts.
I'd also highly recommend a basic digital audio text book, I've found these three to be extremely helpful in understanding this admittedly very complicated and confusing topic:
Mastering Audio, by Bob Katz
The Computer Music Tutorial, by Curtis Roads
The Principles Of Digital Audio, by Ken Pohlmann
Hope that helped a bit an didn't just make things even more confusing!
Gregg
http://hermetechmastering.com : http://www.discogs.com/artist/Gregg+Janman : http://soundcloud.com/babaluma |
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Equilizyme
IsraTrance Junior Member
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593
Posted : Jan 12, 2013 21:59
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astro_traveller
IsraTrance Junior Member
Started Topics :
13
Posts :
65
Posted : Jan 13, 2013 00:25
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@ babaluma.. thanks for the books.. i been reading computer music tutorial and mastering audio all day today. I m still on it.
Things are much clear now. I was thinking Decibel is a actual value like gram or meter but it is logarithmic proportionate value. It took a while to understand the log part, finally i got the idea.
Is very interesting to know that our ears are logarithmic too.
I will continue on reading them.. if i have some questions ill write here again.. any ways thanks heaps for the books.
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Babaluma
IsraTrance Junior Member
Started Topics :
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729
Posted : Jan 13, 2013 10:42
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Suloo
IsraTrance Full Member
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Posted : Jan 13, 2013 14:19
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its also logarythmic because the human ear almost does work logarythmic as well, so db is a logarythmic entity..
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