Levels on the JB3

[phishn]

Hi,

I just got a JB3 and am doint test recording.  What are the levels at the first bar indicator?  below this bar, the rectangle is solid black. above the bar, its striped.  What is the level at the absolute top?

[phishn]

FYI, I'm using a UA-5 so I have no other absolute way to know.

[Brian Skalinder]

The striped area above the black bar on the JB3 represents a clipping signal.  The UA5's red "over" light will trigger at about -3 dB.  The few times I ran UA5 > JB3, I mostly used the JB3 to monitor L/R balance and the UA5 light to monitor levels.  You want the UA5 light flashing pretty regularly, but not pegging "on" for long stretches.

With a bit of practice you can nail down your levels with this method.  I'm sure others also use different methods with success.

[phishn]

Thanks Brian, that's good to know.  I regularly use the red light on the ua-5 and found that a dim flicker seems to yield the best results from the shows I have taped.  The only time I would really use the level bar on the JB3 is to balance the left/right, and if I'm getting a brighter light on the ua-5 than I desire, I would then look at the level bar on the JB3 to determine which channel to tone down a bit.  The JB3 will help fine tune the levels.

[F.O.Bean]

yeah, and when the v3 is HOT, the levels are on the partial line that is "clipping"

[sickrick43]

Bean,

I'm assuming that you're running the JB3 digi off the V3 (of COURSE you are <g>).

If you ARE clipping, it's on the V3, it is pretty forgiving, unless you're slamming the CLIP constantly.  Clipping doesn't occur on the JB3, all it does is record 1's & 0's.  I say "forgiving" on the V3, as the occasional clip doesn't result in the crunchy/static-y digi-noise we're accoustomed to hearing when you clip an A/D.  Since it lacks the compression that mini-me's have, I suspect they calibrate thier clip a little lower than actual hard clip on the A/D.  The V3 is quiet enough internally, that you don't have to run it HOT to get clean results, and the metering is good enuf (vs the minime & others) that you can get it pretty fine tuned.

Rick

Rick

[F.O.Bean]

Bean,

I'm assuming that you're running the JB3 digi off the V3 (of COURSE you are <g>).

If you ARE clipping, it's on the V3, it is pretty forgiving, unless you're slamming the CLIP constantly.  Clipping doesn't occur on the JB3, all it does is record 1's & 0's.  I say "forgiving" on the V3, as the occasional clip doesn't result in the crunchy/static-y digi-noise we're accoustomed to hearing when you clip an A/D.  Since it lacks the compression that mini-me's have, I suspect they calibrate thier clip a little lower than actual hard clip on the A/D.  The V3 is quiet enough internally, that you don't have to run it HOT to get clean results, and the metering is good enuf (vs the minime & others) that you can get it pretty fine tuned.

Rick

Rick

rick, it is DEF forgiving, i have slammed this thing plenty and still have yet to hear it

its a very nice pre/ad combo and i really wish others ears/brains liked it as much as i do

[quantegy]

I usually use the levels on the JB3 and dont pay attention to the UA-5, well, except I wont go past the 9 o'clock position on the levels. I set the levels so the loudest parts may go into the dashed area or right to the top of the solid area. If it happens to be a little quiet, I adjust the levels in Wavelab.

adam

[Todd R]

If you ARE clipping, it's on the V3, it is pretty forgiving, unless you're slamming the CLIP constantly.  Clipping doesn't occur on the JB3, all it does is record 1's & 0's.  I say "forgiving" on the V3, as the occasional clip doesn't result in the crunchy/static-y digi-noise we're accoustomed to hearing when you clip an A/D.  Since it lacks the compression that mini-me's have, I suspect they calibrate thier clip a little lower than actual hard clip on the A/D.  

Rick

Well, not really.  The V3 may have a different calibration level than we are used to, but it is not lower than a hard clip on the A/D.  The V3 bases its clip lights on the digital signal--I think it is 3 straight peak samples equals a clip.  By using the digital signal, it is EXTREMELY accurate.  And people find it "forgiving" since there is no way our ears can hear it when only 3 samples have gone over resulting in clipping.  So when the clip meters on the V3 have just barely been triggered, it will not be audible, but even then you can see the distortion if you look at the waveform in an audio editor.  Others A/D units with less accurate clip meters may easily have a much worse bought of clipping before they are set off, so you may more readily be able to hear it on your tapes.

Most A/D converters, like those onboard Sony portable DAT decks, the DAP1, the SBM1, etc, use analog metering.  So they use the analog signal going into the A/D converter stage to determine if it is at a voltage level that will be too high for the converter stage and will result in digital clipping.  This method of metering is far less accurate.  Mfgs can try their best, but individual variation from player to player will mean that the firing of the clip indicators is never consistent.  I have numerous times had the clip indicators on my M1 go off, when my V3 indicates all is well and good.  When I get the recording home and look at it in CoolEdit, sure enough, the V3 was right and there was no clipping--no distortion of the waveform.

Time for some V3 fluffing:  it is this level of attention to detail and design implementation that makes the V3 rule.  

-Todd

[nickgregory]

Most A/D converters, like those onboard Sony portable DAT decks, the DAP1, the SBM1, etc, use analog metering.  So they use the analog signal going into the A/D converter stage to determine if it is at a voltage level that will be too high for the converter stage and will result in digital clipping.  This method of metering is far less accurate.  

So Todd, let me ask you a question then, when feeding a D100 a digital signal from an SBM-1 is the metering any more accurate on the D100 since it would not be basing it on the analog signal, but instead the digital line in?

[Todd R]

No, neither is more inherently accurate.  Depending on the individual units, one or the other of the D100 or SBM1 may be more accurate in a particular case, but this is just due to chance, not because of the inherent design.  I may have misspoke before.  I know these Sony units use analog metering, but I'm not exactly sure where the analog signal that is used is generated or fed into the clip indicators.  The bottom line is that analog metering is not nearly as accurate as reading the 1s and 0s off the digital stream and using them as a basis for your clip indicators.

[nickgregory]

No, neither is more inherently accurate.  Depending on the individual units, one or the other of the D100 or SBM1 may be more accurate in a particular case, but this is just due to chance, not because of the inherent design.  I may have misspoke before.  I know these Sony units use analog metering, but I'm not exactly sure where the analog signal that is used is generated or fed into the clip indicators.  The bottom line is that analog metering is not nearly as accurate as reading the 1s and 0s off the digital stream and using them as a basis for your clip indicators.

fair point.  I am actually curious, because I am beginning to wonder how much to push the SBM-1.  I will have to post that in another forum  

[Brian Skalinder]

And people find it "forgiving" since there is no way our ears can hear it when only 3 samples have gone over resulting in clipping.

Todd, great stuff.

When I (and perhaps others as well) say "forgiving", I mean the actual audible clips themselves are not nearly as nasty as other ADCs on which I've heard clipping.  Just toying around, I've run my V3 clipping ALL the time, loooong sustained clips, and at worst it sounds a little compressed and fuzzy - very unlike the harsh click/pop/distortion I've heard during heavy clipping on other ADCs.  FWIW.