Topic: levels on d8 question?

[halleyscomet8]

so i was running some test with my new rig last night and noticed something. my levels would peek, but the over indicater never came on. when listening to the tape you can hear the capping, but it still does not show. i am running studio projects c4's>aerco mp2>ad20>d8. is there something i might be doing wrong or do i not have over indicaters? thanks in advance.
dave

[halleyscomet8]

anyone?

[spreadheadtom]

if you run the levels all the way up on a test does the "over" come on?

[Lil Kim Jong-Il]

Are you running digtal in?

iirc, the D8/D7 doesn't show OVR when the external ADC clips.  The D8 just sees a bit stream that it puts to tape.  You need to monitor the OVR indication on the ADC.  I don't recall seeing OVR on the D7 when running the SBM1 or V3 ahead of it, only when running analog in.

[halleyscomet8]

if you run the levels all the way up on a test does the "over" come on?

no they do not

Are you running digtal in?

iirc, the D8/D7 doesn't show OVR when the external ADC clips.  The D8 just sees a bit stream that it puts to tape.  You need to monitor the OVR indication on the ADC.  I don't recall seeing OVR on the D7 when running the SBM1 or V3 ahead of it, only when running analog in.

yes i am running digital in. the mp2 is an aerco, and has no level meters. neither does the ad20. so i guess i just need to keep an eye to not let them get to high on the d8

[spreadheadtom]

so i guess i just need to keep an eye to not let them get to high on the d8

just run low......you can always boost it up later 

[halleyscomet8]

so i guess i just need to keep an eye to not let them get to high on the d8

just run low......you can always boost it up later 

that's my plan thanks for the advice and +t all around

[stirinthesauce]

yeah, Dave, I never get that over message when I know I'm clipping.  Usually try to run mine at around -6db.  Gives me a little room to avoid clipping when it gets really loud.

[ethan]

yeah, Dave, I never get that over message when I know I'm clipping.  Usually try to run mine at around -6db.  Gives me a little room to avoid clipping when it gets really loud.

ugh...at -6db you're losing *half* your resolution

[Kush]

yeah, Dave, I never get that over message when I know I'm clipping.  Usually try to run mine at around -6db.  Gives me a little room to avoid clipping when it gets really loud.

ugh...at -6db you're losing *half* your resolution

What if you record the levels low and then add gain during post? Will that help with the resolution loss? If not, kindly explain.

[Lil Kim Jong-Il]

[What if you record the levels low and then add gain during post? Will that help with the resolution loss? If not, kindly explain.

No it won't recover any resolution you didn't have in the original recording.  If you record a really low signal and then add gain in post, your will also add gain to the noise in your recording.  You get some noise from the analog stages and some quanization noise at the ADC.  So you really want to maximize the signal to noise ratio at the time of capture.

Can't you mod that little ADC box to add an OVR lamp?

[admkrk]

if you run the levels all the way up on a test does the "over" come on?

 

i've never noticed any kind of "over" signal on mine. just the meter hitting 0 and that doesn't always mean it's clipping unless it stays there for awhile.

[Kush]

[What if you record the levels low and then add gain during post? Will that help with the resolution loss? If not, kindly explain.

No it won't recover any resolution you didn't have in the original recording.  If you record a really low signal and then add gain in post, your will also add gain to the noise in your recording.  You get some noise from the analog stages and some quanization noise at the ADC.  So you really want to maximize the signal to noise ratio at the time of capture.

Can't you mod that little ADC box to add an OVR lamp?

Excellent lesson learned, thanks. Pretty soon I will be running an Oade digi-modded UA-5 for my ADC box. I will make sure to get a SVU-1 or a SVU-2 for metering. Aren't these (SVU-1/2) pretty much the standard for metering when using a UA-5? Anyone have additional preferences?

[SparkE!]

yeah, Dave, I never get that over message when I know I'm clipping.  Usually try to run mine at around -6db.  Gives me a little room to avoid clipping when it gets really loud.

ugh...at -6db you're losing *half* your resolution

You're only losing 1 bit of resolution, leaving 15 bits.  You can still approach 90 dB S/N with that.

[ethan]

yeah, Dave, I never get that over message when I know I'm clipping.  Usually try to run mine at around -6db.  Gives me a little room to avoid clipping when it gets really loud.

ugh...at -6db you're losing *half* your resolution

You're only losing 1 bit of resolution, leaving 15 bits.  You can still approach 90 dB S/N with that.

1 Bit == 32768 possible values...still think it's insignificant?

[SparkE!]

yeah, Dave, I never get that over message when I know I'm clipping.  Usually try to run mine at around -6db.  Gives me a little room to avoid clipping when it gets really loud.

ugh...at -6db you're losing *half* your resolution

You're only losing 1 bit of resolution, leaving 15 bits.  You can still approach 90 dB S/N with that.

1 Bit == 32768 possible values...still think it's insignificant?

At 24 bits, 1 bit is 8,388,608 possible values.  It's still a 6 dB degradation on the maximum possible S/N.

Mathematically, losing one bit of resolution is losing half of your possible values, no matter how many bits you start out with.  The question is can you tell the difference between 15 and 16 bits of resolution?  Most people can't.  On the other hand, when you set the gain too high and you need 17 bits rather than 16, you can EASILY hear that.  Setting the gain 6 dB low to avoid clipping in my opinion is a very reasonable tradeoff to make.  When I do that, I give up 6 dB of S/N that I can't easily hear in order to avoid clipping that I definitely CAN hear.

[ethan]

To each his own

To my ears recordings made with peaks in the 0-1 db range sound clearer with more dynamic contrast. Tapes made at too low levels sound muddy and not defined.

So at what point do you hear clips? 3 samples (.06 milliseconds) ? 10 samples (.22 milliseconds)  22 samples ( .5 milliseconds) ?

I maintain that 3-10 sample clips are negligible and are worth the extra clarity you get at nominal levels.

-e

[SparkE!]

To my ears recordings made with peaks in the 0-1 db range sound clearer with more dynamic contrast. Tapes made at too low levels sound muddy and not defined.

-e

Agreed.  It's great to be able to record with peaks in the -1 to 0 dB range.  You can do that if you know that the soundman will leave the levels alone once they're set. In fact, that's what I strive for when I'm in a familiar venue with a good soundman. It's just a matter of being sufficiently familiar with your recording environment.

The first time at a venue, I'll err to the low side on levels, though, in case they have a soundman that can't seem to quit turning up the levels.  They usually won't go up by more than 6 dB at a time, so my 6 dB margin is usually enough to keep from spoiling a recording by clipping.

[stirinthesauce]

To my ears recordings made with peaks in the 0-1 db range sound clearer with more dynamic contrast. Tapes made at too low levels sound muddy and not defined.

-e

Agreed.  It's great to be able to record with peaks in the -1 to 0 dB range.  You can do that if you know that the soundman will leave the levels alone once they're set. In fact, that's what I strive for when I'm in a familiar venue with a good soundman. It's just a matter of being sufficiently familiar with your recording environment.

The first time at a venue, I'll err to the low side on levels, though, in case they have a soundman that can't seem to quit turning up the levels.  They usually won't go up by more than 6 dB at a time, so my 6 dB margin is usually enough to keep from spoiling a recording by clipping.

Nicely put.  My reasoning exactly on my previous statement.  I think the original question was referring to reading levels on a d8, which, IMO, is not exactly the easiest.  A lot easier, at least for me, to *dial in* on the -1 to 0db range when I'm viewing levels via wavelab on my laptop in a venue where I know what to expect.  Maybe I should get a SVU and I wouldn't have this problem (or glasses)   Anyways, great discussion on the tech info with bit resolution and s/n.  Learned something new, +t's!

[ashevillain]

Do you know you are adding gain with both of those boxes? just checkin...