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#1
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Someone says "anything over -10db in digital video is distortion" and you say....
Someone made the statement that "on a digital video deck you want to keep
the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". What say any of you? Thanks for all shared wisdom. |
#2
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On Tue, 21 Jun 2005 21:00:43 GMT, "Doc"
wrote: Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." I think this person is mixing-up two things. Yes, you keep your levels below -10dB in the digital domain, and you do this in order to avoid them reaching 0dB, because that is where they clip. The area between -10dB and 0dB is what is called "the headroom", and is there for louder sounds (plosives, cough, whatever). -10dB is quite high actually, if you don't know exactly what you're doing. You can pick your choice between -12dB, -14dB, -18dB and even -20dB. All these values are used as safeguard against clipping, and each soundo has his own standard. I use generally -12dB for normal dialogue, and -18dB if I don't know what could happen. But you will have to find your own comfort-zone, because mine does not need to be yours cheers -martin- -- "Now I want you to say it thrice daily and don't dress a bun" |
#3
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"Doc" wrote in message
nk.net... Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". What say any of you? Thanks for all shared wisdom. You are correct. I think the intent may have been to say that metering, being what it is, an average of -10 (or -8 or -18 or ??) is a good place to place the average peaks, because there will often be peaks that exceed the average by 10 db or so. Therefore, to avoid clipping set a level that will acommodate all peaks so that none exceeds the brick wall 0 dbfs. Steve King |
#4
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Martin Heffels wrote: On Tue, 21 Jun 2005 21:00:43 GMT, "Doc" wrote: Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." I think this person is mixing-up two things. Yes, you keep your levels below -10dB in the digital domain, and you do this in order to avoid them reaching 0dB, because that is where they clip. The area between -10dB and 0dB is what is called "the headroom", and is there for louder sounds (plosives, cough, whatever). -10dB is quite high actually, if you don't know exactly what you're doing. You can pick your choice between -12dB, -14dB, -18dB and even -20dB. All these values are used as safeguard against clipping, and each soundo has his own standard. I use generally -12dB for normal dialogue, and -18dB if I don't know what could happen. But you will have to find your own comfort-zone, because mine does not need to be yours cheers -martin- And also the short plosives or other short transient sounds may not register fully on the meter or led's so they may be well over 0 dB but don't register over 0 dB. I actually thik people should pay more attention to the AVERAGE meter reading rather that the peak. Pick a level say -15 dB and try to set the level so that 1/2 the time the meter is above -15 and 1/2 the time it is below. If you do it this way, the "loudness" i.e how loud it actually sounds ... will be more consistent. Mark Mark |
#5
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Doc wrote:
Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". What say any of you? Thanks for all shared wisdom. This person is mixing levels....-10dB is a line level voltage for certain equipment, not a reference point for where clipping begins. 0dB is the absolute ceiling of the loudest volume that can be recorded on digital equipment (ie. 16 1 bits for that sample). It's possible for a -15dBu signal to cause clipping on some equipment, and a +5dB u signal to be below clipping on other equipment. Many people and software will consider the point at which you reach, but not exceed 0dBFS to be clipping, simply because they are both represented the same way in binary (all 1's) Other people, like myself, believe that clipping may occur, but only matters when you can hear it. Some equipment handles clipping really well, and if you're recording a thrash distorted guitar part you might not even notice lots of clipping. On the other hand, if you're recording clean vocals, you probably won't be fine with even minimal clipping. But yes I think you're right, clipping occurs when they are no more zeros to turn on to represent the extra signal, or there are no more metal oxide particles in a tape to represent the xtra signal/information. Jonny Durango |
#6
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Doc wrote:
Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Most digital equipment clips someplace in the last 1 dB before FS. Up until that point, digital equipment is generally very clean. However this begs the question - how are you measuring levels? There's really only one totally reliable way to measure levels in the digital domain, and that is to record a sample and then look at it with a DAW. What you actually record is where the rubber hits the road. Everything else is an estimate. Further they state that 0db is the same as clipping. In many cases, clipping of real world digital equipment takes place a bit below 0 dB, IOW -0.1 dB or maybe even as low as -0.5 dB. Furthermore, clipping might be frequency-dependent. If clipping is frequency-dependent, the clip point is probably the lowest at the highest frequencies. Most equipment will hit its highest undistorted levels at 10 KHz, but there may be increasing losses at higher frequencies. Most of my cautionary comments apply to the less expensive digital equipment. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Fact is, a lot of digital equipment clips at some point above -1 dB, but below 0 dB. Soundforge definitely makes a distinction between 0db and "clipped". Theoretically, 0 dB signals are not clipped. |
#7
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Jonny Durango wrote:
But yes I think you're right, clipping occurs when they are no more zeros to turn on to represent the extra signal, or there are no more metal oxide particles in a tape to represent the xtra signal/information. Jonny Durango You'd hear the clipping at playback with D/A conversion, correct? Then wouldn't it depend on the converter? If the converter created a smooth peak (possible?) would that explain why some equipment handles it better? -- - Bill |
#8
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"Doc" wrote in message nk.net... Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". I think I should clarify, this is referring to material that's already been recorded, not a question of where to set the levels during recording. I was under the impression that the waveform and VU meter in Soundforge etc. "shows all". That there are no peaks that don't show up on the wave form and the VU meter tells you exactly what the peak levels are up to 0db, unlike analog meters which show an approximation of the peaks, which are likely somewhat below the actual levels. Yes? No? |
#9
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Doc wrote: Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". What say any of you? Thanks for all shared wisdom. In an environment with digital and analog VTRs "tone" always is set to read 0 on an analog VU meter and -20 on a digital meter. I am referring mainly to Beta SP (analog) and Digi-Beta (digital machines) With properly recorded audio the level on a Beta SP deck will fluctuate around the 0 level marker but sometimes read a couple of db over. The same audio will read maybe 10 db above the -20 marker on the digital machines due to it's "peak reading" tendencies. In the old days (with tape) when there were only VU meters an engineer had to "just know" that certain sounds would read much lower on a VU meter than they really were. An extreme example would be orchestra bells or a triangle. If you let the level approach -10 on a VU meter the sound would be distorted. This was especially important on the first generation of the recording. Some of the extreme peaks would saturate the tape but in a gentle way. Later in the "mix" you could boost these same sounds and avoid the distortion because the extreme peaks in the overtones were now gone. |
#10
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Assuming the meter shows the true instantaneous peak level, this is utter
crap. On a digital recorder, the higher the recording level the _lower_ the distortion -- until you exceed 0dB, at which point you clip. |
#11
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"Arny Krueger" wrote in message ... Doc wrote: However this begs the question - how are you measuring levels? There's really only one totally reliable way to measure levels in the digital domain, and that is to record a sample and then look at it with a DAW. Soundforge. In case you haven't seen my previous posts I'll give you a quick rundown. Made a Firewire transfer of a musical performance from a DVCam deck to my Sony TRV-240 Digital8 camcorder. From there through a Firewire port to my H/D. When looking at the still unprocessed file I found that the highest peaks were either right at 0db or registered as clipped. All the highest peaks were in one particular song which was somewhat higher in level than the rest of the performance. I should probably mention that the people who recorded the sound at the performance really messed up all over the place - they showed up late and didn't get to do a sound check. Her vocal levels were all over the place in the mix from hot and distorted to buried. Half the time she couldn't hear herself in the monitors. Her mic died during one song. During the opening bars of the performance (for TV), someone apparently hit the "on" button on the onboard reverb - suddenly the sound is awash in ridiculously overboard reverb and a couple of seconds later it suddenly goes away (I can just see the board guy fumbling in a panicked scramble for the fader or pot.) It was apparent from the shape of the waveform that for some reason the first and last songs had compression/limiting applied to them - with a lot of accompanying distortion - I assume with an onboard compressor/limiter they had. Why just the first and last songs I have no idea. Given everything else that happened, I have to wonder if they even knew they were doing it. Can't imagine why the TV studio would do it. Anyway, the fact is there's distortion all over the place, even in places where the sound is nowhere near clipping. It's not caused by my gear, the VHS copy the station gave her of the original tape sounds the same way. I used Soundforge to add reverb via the Acoustic Mirror plugin. To do this, I had to lower the overall levels by 2db to keep many more peaks from clipping than already were once the reverb was applied. I figured I should put it back to where it was, i.e. with the highest peaks (maybe 2 or 3 spikes where this ocurred) at 0db, which is what I did. Saved the whole thing with the DV format, played it back to my camcorder via firewire and then back to their DVcam deck. When I mentioned to the Station manager about the levels issue, he seemed incredulous that any of them were that hot. I explained that this is where they were on the original file. He even asked if I had "adjusted" anything during the Firewire transfer. I'm not aware that this is even possible. I was under the impression that a Firewire transfer is utterly unlike going from an analog source, that a transfer simply dumps whatever data is on the digital tape to the h/d, no user intervention possible. At any rate, all I did was set up the cam, hook up the Firewire cable and hit "capture" on the Pinnacle Studio 9 software. |
#12
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#13
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Mike Rivers wrote:
In article et writes: Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." That would be a pretty bad digital video deck, however they may want to keep the peaks 10 dB below full scale because they want to have 10 dB of headroom in their playback chain. It could be that the deck that they play back from produces an analog output from a -10 dBFS digital recording that drives their system into clipping, but that's sloppy system engineering on their part. Agreed, but it's surprisingly common in the broadcast world. In any case, it's convention, and a trade organization (SMPTE) standard, to deliver recordings that don't peak above -10 dBFS. Yup, gotta waste that last 10 dB by design. Sigh... |
#14
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Doc wrote:
When I mentioned to the Station manager about the levels issue, he seemed incredulous that any of them were that hot. I explained that this is where they were on the original file. He even asked if I had "adjusted" anything during the Firewire transfer. What's to adjust? ;-) I'm not aware that this is even possible. I was under the impression that a Firewire transfer is utterly unlike going from an analog source, that a transfer simply dumps whatever data is on the digital tape to the h/d, no user intervention possible. That's my experience. At any rate, all I did was set up the cam, hook up the Firewire cable and hit "capture" on the Pinnacle Studio 9 software. I've done my camcorder transfers using real basic software and hardware - namely Windows Movie Maker (WMM) and a generic Firewire card. It seems to work like clock - I push some buttons, wait for a while and there's an AVI file on my hard drive. If I need to play with the sound track more seriously than what WMM allows, I've used Audition/CE to pull the sound track off of the computer file that Windows Movie Maker created. WMM supports adding a stereo audio track back into the movie from my hard drive. Since the audio is always kept in the digital domain, there's really not a lot to mess it up. It is what it is, until I start playing with it with one of the editors that I use. |
#15
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On Tue, 21 Jun 2005 23:11:40 GMT, "Doc"
wrote: I'm not aware that this is even possible. I was under the impression that a Firewire transfer is utterly unlike going from an analog source, that a transfer simply dumps whatever data is on the digital tape to the h/d, no user intervention possible. You are right. -m- -- "Now I want you to say it thrice daily and don't dress a bun" |
#16
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I haven't read all the posts , but -10 digital seems to becoming a new
T.V. standard , From feeding cameras to the quality control inspector at discovery channel sending shows back if there are peaks over that ! Maybe Will , will lend his experience , but it seems to combatting sloppy field work and over agressive transmitter chains . regards Greg "Doc" wrote in message nk.net... Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". What say any of you? Thanks for all shared wisdom. |
#17
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#18
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FWIW, we set reference tone at -10 on the DV deck's meters when recording
dialog. For music, we usually use -12. But on dialog, we're nearly always compressed at least 3:1 at the mixer, so the 10 is more like 30. And for music, there's just too much the audio guy does to the 2-mix to fully explain here, but for levels, there's usually a compressor on most every input (some of them 2-stage). For critical events, there's a separate multi-track recording for re-mix, etc. Steve "Steve King" wrote in message ... "Doc" wrote in message nk.net... Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. Soundforge definitely makes a distinction between 0db and "clipped". What say any of you? Thanks for all shared wisdom. You are correct. I think the intent may have been to say that metering, being what it is, an average of -10 (or -8 or -18 or ??) is a good place to place the average peaks, because there will often be peaks that exceed the average by 10 db or so. Therefore, to avoid clipping set a level that will acommodate all peaks so that none exceeds the brick wall 0 dbfs. Steve King |
#19
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On Tue, 21 Jun 2005 23:16:48 +0200, Martin Heffels
wrote: On Tue, 21 Jun 2005 21:00:43 GMT, "Doc" wrote: Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." I think this person is mixing-up two things. Yes, you keep your levels below -10dB in the digital domain, and you do this in order to avoid them reaching 0dB, because that is where they clip. The area between -10dB and 0dB is what is called "the headroom", and is there for louder sounds (plosives, cough, whatever). -10dB is quite high actually, if you don't know exactly what you're doing. You can pick your choice between -12dB, -14dB, -18dB and even -20dB. All these values are used as safeguard against clipping, and each soundo has his own standard. I use generally -12dB for normal dialogue, and -18dB if I don't know what could happen. But you will have to find your own comfort-zone, because mine does not need to be yours Over here in the BBC, we use -18dbfs as our reference level and we set our peak to 8db higher than that - ie -10dbfs. This ensure that there's always 10db of headroom before the onset of clipping. Steve The Doctor Who Restoration Team Website http://www.restoration-team.co.uk |
#20
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The general standard for video in the US is (and has been for quite
some time) peaks at -10 and vu levels peaking between -18 and -24. While this standard does fail to take advantage of the additional 10db of headroom available in the digital realm, it allows for a seamless signal flow between analog and digital machines. This is not the case with DVDs, where there is not yet a clear standard established. |
#21
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#22
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"Doc" wrote:
Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." They *might* have meant that it causes distortion further down the chain. Or maybe they're just unclear on the details. Either way, the standard in digital video these days is 0VU = -20dBFS with peaks not exceeding -10dBFS. Some facilities nudge the 0VU mark up or down a bit, but the -10dBFS ceiling seems pretty consistent. -- "It CAN'T be too loud... some of the red lights aren't even on yet!" - Lorin David Schultz in the control room making even bad news sound good (Remove spamblock to reply) |
#23
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"Lorin David Schultz" wrote in message
news:rGyve.60173$wr.18573@clgrps12... "Doc" wrote: Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." They *might* have meant that it causes distortion further down the chain. Or maybe they're just unclear on the details. Either way, the standard in digital video these days is 0VU = -20dBFS with peaks not exceeding -10dBFS. Some facilities nudge the 0VU mark up or down a bit, but the -10dBFS ceiling seems pretty consistent. Of course, haven't we all seen the postings about Sony PD150/170 cameras and their prosumer equivilents VX2000/2001 that will deliver excessively noisy results at those settings? It is my understanding that other manufacturers of this category of camera suffer similarly. Shortly after I switched from BetaSP to DVCAM I had to reschedule an interview that was recorded to the standards suggested by Lorin on a PD150. The result was simply too noisy to use. It was an honest mistake by an experienced sound professional who tried to apply standards that worked with analogue BetaSP to a new digital format that simply doesn't have the capability to accommodate 20 dB of headroom. (As a side note, the second interview was a bust. The spontanaity of the first sitting was gone. Caution replaced candor. It will, unfortunately, not be used in the documentary that is still an ongoing project.) Steve King |
#24
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#25
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"Mike Rivers" wrote in message
news:znr1119798122k@trad... In article writes: Of course, haven't we all seen the postings about Sony PD150/170 cameras and their prosumer equivilents VX2000/2001 that will deliver excessively noisy results at those settings? Not me, but then I don't travel in those circles. I'm not sure what you mean by this, but the topic of audio problems with the PD150 and VX2000 have been discussed on this newsgroup as well as more extensively on RAMPS. I'll include a quote from Jay Rose about the PD150: "Sony started with the inferior preamp/AD in their VX2000, and added balancing and phantom. Period. When the world complained about the awful s/n, they (AFAIK) added a software-based noise gate. No per-unit cost, those clever guys... If you do a traditional measurement with an input signal that goes away -- what Sound Devices did -- the gate kicks in and s/n is apparently improved. It's simply a single-band masking phenomenon... the noise is still there, and apparent with some signals." It is my understanding that other manufacturers of this category of camera suffer similarly. Shortly after I switched from BetaSP to DVCAM I had to reschedule an interview that was recorded to the standards suggested by Lorin on a PD150. The result was simply too noisy to use. It was an honest mistake by an experienced sound professional who tried to apply standards that worked with analogue BetaSP to a new digital format that simply doesn't have the capability to accommodate 20 dB of headroom. According to the classic definition, no digital system has any headroom. I was speaking of the 20 dB between -20 dBfs and digital full scale, but thanks for the lecture anyway. When you get to 0 dBFS, you have no place else to go. You make your own amount of headroom based on your familiarity (or unfamiliarity) with the program material, and adherence to the client's wishes. At -20 dBFS, in even the crummiest of the crummy, you should have at least 60 dB of dynamic range available. Are you suggesting that you barely have 20 dB of dynamic range below -20 dBFS? That's absurd. What I tried to say, perhaps not well, is that if the tone is set at -20dBfs and program peaks are allowed to go no higher than -16 dBfs on a PD150 with the internal limiters off, audio recorded in a quiet setting will have an objectionable amount of pre-amp noise. I am simply relating my experience in hundreds of hours of shooting with PD150s and VX2000s and making my evaluations based on 40 years of broadcast, recording studio, and video production experience. But, I'm still learning every day ;-) Maybe someone told him "record beween -10 and -20" and he was watching the VU meter on his mixer barely move off the downscale pin. That, of course, won't word, since 0 VU is calibrated to some nominal level which is probably in the ballpark of the nominal recording level, analog or digital (unless there's a +4/-10 discrepancy that nobody accounted for). Unfortunately, I was the director, so if there was any telling going on it was me doing it. It was a very early shoot with the PD150 and the first interior in a quiet office. Previous locations had been in exterior locations, where ambient noise masked the camera audio deficiencies. All that said, when one knows the inherent problems of the Sony cameras, they can deliver excellent picture results and satisfactory audio tracks. I have since adopted a working method for run and gun using a microphone (or wireless receiver) directly into the camera of leaving the internal limiters on and adjusting levels to peak around -6 dbfs. The internal limiters are not great, but they do prevent clipping. This seems to be an acceptable compromise. When feeding the cameras from an external mixer better results can be had by turning off the internal camera limiters and using the mixer limiters to keep audio from exceeding digital full scale yet still peak around the -6 dBfs point. Steve King I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
#26
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#27
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"Mike Rivers" wrote in message
news:znr1119821439k@trad... In article writes: Well, that's (as Jay said) because they use crappy preamps. It's not a fault of the medium or method. I wouldn't tolerate a piece of equipment that poor. You just can't work with it. I wish I could adopt that attitude, but the sad fact is that there is about a $30,000 cost difference to step up to something significantly better, and my competition is using the low priced spread leaving me not much choice. If it has that poor a noise floor, I'd suspect that it probably also starts to distort, or maybe even clips, when you put enough level into it to reach full scale. But since I don't have one, I can't confirm any of this. For corporate work we're managing fairly well with the method below. I've had a few projects that included some music, where I went double system. All that said, when one knows the inherent problems of the Sony cameras, they can deliver excellent picture results and satisfactory audio tracks. I have since adopted a working method for run and gun using a microphone (or wireless receiver) directly into the camera of leaving the internal limiters on and adjusting levels to peak around -6 dbfs. The internal limiters are not great, but they do prevent clipping. This seems to be an acceptable compromise. Steve King |
#29
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"Doc" wrote in message nk.net... Someone made the statement that "on a digital video deck you want to keep the levels below -10db because above that you're into distortion." Sounds like they were refering to some sort of local "stanndard" for keeping the average at -10dBFS to allow 10dB of hedroom. 10dB seems pretty risky unless you have a very predictable source. Most of us use -20dBFS as the reference (it would have been called the 0dB point back in analog days.) Further they state that 0db is the same as clipping. I was under the impression that attempting to *exceed* 0db yields clipping, since there isn't anything over 0db. In the real world the difference between 0dB and OVER 0dB is nonexistent. Nobody can adjust levels to keep the signal peaks at 0 without going over. Some compressors can come very close, but you don't want to hear what happens to your audio when you push it that close. Soundforge definitely makes a distinction between 0db and "clipped". Soundforge is working on after-the-fact files, not real-time recording level setting. |
#30
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I use Dorrough 280-D meters, which display vu and peak levels
simultaneously. Since -20 on the digital scale = 0 vu, vu levels peaking between -18 and -24 on the digital scale = +2 to -4 in the analog realm, so long as machines are calibrated to -20. Sorry this wasn't clear in my last post. Mike Rivers wrote: In article .com writes: The general standard for video in the US is (and has been for quite some time) peaks at -10 and vu levels peaking between -18 and -24. That's true for digital peak levels, which are not indicated by a VU meter. Do you know where the -18 to -24 range on the VU scale is? Let's not get our meters confused. |
#31
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On Sun, 26 Jun 2005 14:09:27 GMT, "Lorin David Schultz"
wrote: Either way, the standard in digital video these days is 0VU = -20dBFS with peaks not exceeding -10dBFS. Avid seems to think 0VU=-14dBFS. I know I am whinging here, but your standard does not have to be my standard. If you want to speak about such a standard, it is wise to add in which country you are, so people can apply your suggestions to their situations. cheers -martin- -- "Now I want you to say it thrice daily and don't dress a bun" |
#32
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#33
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"Mike Rivers" wrote in message
news:znr1119872579k@trad... In article writes: Well, that's (as Jay said) because they use crappy preamps. I wish I could adopt that attitude, but the sad fact is that there is about a $30,000 cost difference to step up to something significantly better, and my competition is using the low priced spread leaving me not much choice. How about adding a $200 Beachtech mic preamp to it? (Jay likes that one). It reduces portability a bit, but it might get a good mic signal recorded for considerably less than $30,000. I've seen his posts on the Beachtech. I've also used the MixPre and SD 302. Jay's recommendation of setting the camera level controls about midway on their range and feeding -30 dB from the mixer works pretty well. Even better are also a couple of modifications, which I believe bypass the swine internal pre-amps, that make a remarkable difference. The BBC was the first I heard of to make this mod, since they were using so many of the Sony PD150s and even VX2000s on their documentary shoots. Steve King |
#34
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#35
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I'm with ya Mike. In addition to the Dorroughs, I have an old pair of
analog vu meters I keep an eye on as well when setting levels. |
#36
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Message-ID: X-Complaints-To: X-Abuse-Info: Please forward a copy of all headers for proper handling X-Trace: bhmkggakljkaanefdbdpiflmbcekedmfhojhikkbagflhcbong fngfmogdnmjkkodillphahkfobdkeoeibhhpbkeeaafoaikbla hielgmpocbjfbbjgahaalefbllalipgckcofeddglkcgnggloc lddeclkeoo NNTP-Posting-Date: Mon, 27 Jun 2005 22:01:54 EDT Organization: BellSouth Internet Group Date: Tue, 28 Jun 2005 02:01:54 GMT Xref: number1.nntp.dca.giganews.com rec.video.desktop:472669 rec.audio.pro:1182795 rec.video.production:224082 On 2005-06-27 said: writes: I use Dorrough 280-D meters, which display vu and peak levels simultaneously. Since -20 on the digital scale = 0 vu, vu levels peaking between -18 and -24 on the digital scale = +2 to -4 in the analog realm, so long as machines are calibrated to -20. Sorry this wasn't clear in my last post. That's a good meter and it tells you a lot. Being an old fuddyduddy myself, I still use an analog console with pretty close to real VU meters on it. I find that with my digital stuff calibrated so that 0 VU equals -20 dBFS, by watching the VU meters the way I always have, I get perfectly satisfactory record levels. Ditto here. I have a vu indicator which gives me an audible tone at 0vu and set things up with my wif's help using her eyes so that a 1 khz tone generates -20 dbfs once we've gone over to digital. I get satisfactory recordings this way. Some people think that when they look at the waveform view on their DAW and the squiggles don't fill up the full track width, they have a "weak signal." I keep reminding them that -6 dBFS, which is a reasonably hot level, only uses half the graphic height, so -10 dBFS is just a wiggly line down the middle. That's why they have zoom buttons on these things. I remind them that it's audio, you're supposed to use your friggin' ears!!! That's why we ahve another thread about why it has to be so f**ing loud which has been hijacked into an analog vs digital thread. Richard Webb, Electric SPider Productions, New Orleans, La. REplace anything before the @ symbol with elspider for real email -- THe knobs turn in both directions". That's why it's called mixing, otherwise we would call it adding |
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Steve King wrote:
"Lorin David Schultz" wrote in message news:rGyve.60173$wr.18573@clgrps12... the standard in digital video these days is 0VU = -20dBFS with peaks not exceeding -10dBFS. Some facilities nudge the 0VU mark up or down a bit, but the -10dBFS ceiling seems pretty consistent. Of course, haven't we all seen the postings about Sony PD150/170 cameras and their prosumer equivilents VX2000/2001 that will deliver excessively noisy results at those settings? It is my understanding that other manufacturers of this category of camera suffer similarly. Right, -12 dBFS is generally a better reference level for most DVcams. Having an external preamp or mixer with a decent limiter helps quite a bit. |
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"Richard Crowley" wrote in message ... Soundforge definitely makes a distinction between 0db and "clipped". Soundforge is working on after-the-fact files, not real-time recording level setting. Right, that's what I was referring to, material that's already been recorded. When I got it, it had a few peaks of 0db and some that were clipped. |
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"Steve King" wrote:
[...] Shortly after I switched from BetaSP to DVCAM I had to reschedule an interview that was recorded to the standards suggested by Lorin on a PD150. The result was simply too noisy to use. It was an honest mistake by an experienced sound professional who tried to apply standards that worked with analogue BetaSP to a new digital format that simply doesn't have the capability to accommodate 20 dB of headroom. Hey, don't blame me! I just stated the facts, I didn't set the standard! g Our SX camcorders are all calibrated to 0VU = -20dBFS and we don't have any noise problems. Of course, you could buy a truckload of PD150s for what one of those costs though. -- "It CAN'T be too loud... some of the red lights aren't even on yet!" - Lorin David Schultz in the control room making even bad news sound good (Remove spamblock to reply) |
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"Martin Heffels" wrote:
Avid seems to think 0VU=-14dBFS. Which Avid? Ours is -20. I know I am whinging here, but your standard does not have to be my standard. If you want to speak about such a standard, it is wise to add in which country you are, so people can apply your suggestions to their situations. There seems to be a whole lotta "shoot the messenger" coming from one of the groups to which this thread is cross-posted. I didn't establish the standard, I'm just quoting it. Whether anyone chooses to observe it or not is no skin off my meters... like I said, I didn't come up with it so my feelings won't be hurt if someone doesn't like it (though a committee at Sony may take you off their Christmas card list). Maybe it's different across the pond (I'm in North America), but I don't think so. I think it's just a case of some people and organizations choosing to adopt different approaches. Any piece of digital pro video gear I've ever encountered has the zero VU mark at -20 on the meters (note that I've not actually seen the Avid to which you refer). Maybe other devices that I haven't seen are different. Anyway, how does your comment relate to the original poster's question? -- "It CAN'T be too loud... some of the red lights aren't even on yet!" - Lorin David Schultz in the control room making even bad news sound good (Remove spamblock to reply) |
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