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#1569638 - 04/22/18 06:45 AM The +4 Dilemma
haysonics Offline
Planeteer


Registered: 12/10/13
Posts: 80
Loc: Sydney, Australia
I have a dilemma and am wondering if its just me or whether its a hangover from the days of tape that modern folk face at some point?

Although one engineer told me that "line level" covers a range of dB I have always thought of it as +4. My Roland JP8000 synth has a 1/4 inch "line out" jack and if I select the loudest sound and press all my fingers hard onto the keys I get +4.

If I play that +4 sound into my VS2000 (I am using 16 bit) it reads -20 DBFS. That makes sense as the machine is calibrated so that +24 = 0 DBFS. That calibration is a hangover from analogue mixers/consoles that could handle +24. Analogue consoles could handle that level so digital consoles needed to handle that level.

I am under the belief (correct me if i am wrong) that the optimal input level for tape was +4. Tape had some headroom, headroom that varied depending on which brand/formula you used and whether you ran your tape at 15 or 30 IPS. The VU meters were calibrated so that 0 VU = +4. Engineers liked to see levels from 3 to 6 VU for the sound benefits of tape saturation/compression. But if you were recording classical music you likely aimed for +4.

Those working in 24 Bit can run their signals in at +4 but those using 16 Bit since the days of ADAT (like me) tend to run their levels in much hotter, either because they come from old signal-to-noise training (tape) or the concern that they achieve at least 14 bit resolution (-12 DBFS peaks) for tracking and 16 bit (0 DBFS) for the finished mix. Although headroom is handy, I have enough experience to avoid digital distortion. For me the beauty of 24 Bit is not the headroom, it is that a +4 signal gets 20 Bits of resolution. Working with 16 Bit mode I have to get my signal up to +24 to obtain 16 bit resolution. But that has not been an issue as the VS preamps can take a +4 signal up to +23.9 without distortion. The ADC don't seem to have a problem with that level. All is well with the machine.

And so after all that, here is the dilemma. I have a finished mix at 0 DBFS. I would like to send it to analogue outboard gear for mastering. My VS2000 will send it out at +4 which is fine as my outboard hardware is optimised for +4. The signal comes back into my VS2000 at +4. BUT, BUT, now I have to gain amplify back up to +24 = O DBFS. It doesn't sound great. I want to avoid reamping. Its my dilemma because i just happen to be using 16 Bit and just happen to be wanting to run a mix through analogue gear. Its a dilemma based on a hybrid setup. If I was using the 3 card plugins I could process at close to 0 DBFS. It might be a rare issue these days but i suspect quite a few who worked with 16 Bits in the past would know of it.

Have any of you faced this?

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#1569694 - 04/23/18 08:39 AM Re: The +4 Dilemma [Re: haysonics]
keeppracticing Offline
Planeteer


Registered: 07/13/12
Posts: 1217
Loc: Atlanta
Seems as though you've either got to use the 3 card to stay in-box or have a great ADC/DAC and great external hardware with an output knob that can get you the level you need in a way that sounds even better than before (as that's the whole point.)
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#1569798 - 04/24/18 05:02 PM Re: The +4 Dilemma [Re: keeppracticing]
haysonics Offline
Planeteer


Registered: 12/10/13
Posts: 80
Loc: Sydney, Australia
That's right. I optimised my gain staging for 16 Bit so I'll need to find a piece of equipment that will record a +4 signal as 0 DBFS. A CD player outputs +4 so it is converting digital 0 DBFS to analogue and then gain amplifying it to +4 using a opamp (same thing the opamp in a preamp is doing). But the CD player is working from 0 DBFS rather than attenuating down to -20 DBFS and then up again to 0 DBFS (reamping) which is essentially what the VS is forcing me to do when it has a +4 input equaling -20 DBFS. That's less of an issue in 24 bit where -20 DBFS gives you 20 bit resolution and a lower noise floor. But its still a reamp and not ideal.

Maybe there is a standalone ADC with a setting for folk like me. Then I could go VS aux out > Pulteq > ADC > VS digital in.

But if not then for the next project i'll make the switch to 24 Bit and track and mix at +4 so can also buy hardware clones of the 1176 and LA2A and not run into the same dilemma. The 3 card plugins are excellent so I didn't feel the need to go out of the box until I wanted to use hardware Pulteq EQP for a mix. If they had made a Pulteq plugin for the 3 card it would have been close enough. I'll avoid RDAC so unfortunately it will be a move to the dark side (PC).

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#1569840 - 04/25/18 09:55 AM Re: The +4 Dilemma [Re: haysonics]
keeppracticing Offline
Planeteer


Registered: 07/13/12
Posts: 1217
Loc: Atlanta
A Lynx Hilo would do it.

VS coax/optical digital out> Hilo DAC line out> Pulteq> Hilo ADC line in> Hilo digital out> VS

The Hilo is awesome.

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#1570028 - 04/28/18 02:47 AM Re: The +4 Dilemma [Re: keeppracticing]
haysonics Offline
Planeteer


Registered: 12/10/13
Posts: 80
Loc: Sydney, Australia
I'll download the manual and see if it has a setting for +4 to equal 0 DBFS without having to use its analogue amp section.
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