-10db or +4db? roland jv1010 and mixer

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Flash

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Hey guy's, Just wanted your input on my D-man 2044 card! Here's what I'm doin' right now, I have my roland jv-1010 output hooked to input 3&4. I have a peavey 12 channel mixer hooked to input 1&2 which I use for mic's, guitar's, keyboard's etc. etc.
My question is on the roland would I want to set my card to -10 or +4? And on the mixer I'm thinking that should be set to +4db on the D-man...... What do you think?
 
If you have the JV 1010 hooked up "directly" to the soundcard, the soundcard should be "-10", because the JV1010 is unbalanced (-10). For the mixer, it depends. I'm not sure about the outputs of your mixer. Read the manual or look on the back of the mixer. If the output of the mixer is "balanced", then put the soundcard's inputs on "+4" for the mixer channel. If not, use -10.

E
 
kooooool man, Well I set mine to the +4. And in the mean time tried some things with my mixer with info I got off the cakewalk site and found out with my D-man 2044 and my peavey mixer that now I have 4 tracks at once. Now I run my Jv1010 through the mixer, guitar and vocals and keyboard. Can't wait to get that Delta 1010. Oh, and at +4 it is much quiter.
 
Dobro,

I wonder if your test was testing "apples versus oranges". In your test, did you test "XLR" cables versus "RCA" cables? You didn't really specify in the thread. Plus, from my experience at +4 with an unbalanced signal you will get a lower signal than a "-10" input with an unbalanced signal. I'd be willing to bet that what you are hearing as a quieter track is really just a lower signal which is the lower in level than the other.

In order to truly compare the relative noise of two input levels, you ned to make the waves equal to each other in volume. So an appropriate test would be recording the same signal at the two levels and then using a wave editor like Sound Forge or Wavelab to match the levels of each track. One way to match the levels is to normalize each track. Once this is done THEN you compare noise levels. I'd be willing to bet that then you'd find that the "+4" track is actually noisier. It's a simple signal-to-noise issue.... A lower level input signal (+4) is always going to be lower in volume to a higher level input (-10) when comparing two of the same signal "at the SAME level".

My advice to Flash is to check it for himself, following my above suggestions. What he'll find is that the "-10" input give a higher signal-to-noise recording, since the level is matched to the JV 1010's output. This applies IF he's hooking up the JV1010 directly to the soundcard. Coming out of the mixer is another story. Because many mixers have balanced outputs operating at "+4".

E
 
That's what I did, I put the Jv1010 to the mixer which is balanced. So I went with the +4 setting.
 
Hey, RevE. I don't want to be a bozo about this, but you might want to check your numbers. 0dB with a reference level of -10dBV is actually a _lower_ level than 0dB with a reference level of +4dBm or +4dBu...

A 0dB VU meter reading with respect to -10dBV reference is 0.316 Vrms. A 0dB VU meter reading with respect to +4dBm is 0.7754 Vrms. The "canonical" +4 signal is actually 11.78dB hotter than the "canonical" -10 signal (rather than the 14dB you'd probably expect by simply subtracting), because they are defined as being driven into different impedances. It's a long, nerdy story we've dug into elsewhere here on the site....

0VU at +4 really *is* hotter, electrically, than 0VU at -10. Really. That's why the noise is less noticeable with the +4 reference level: it's the same noise, electrically, but it is basically 12dB quieter with respect to your signal; *by definition*...
 
skippy (and others),

I'm aware that the "+4" level is technically hotter. I remember reading a great article on www.prorec.com from Lionel Drummond that discussed that the "+4" input is actually "11 dBs" hotter than the "-10" input. BUT, those levels are relative to the recorder. When the soundcard gets the signals they're all transformed to the same scale (i.e. once a signal is recorded onto hard disk or tape ALL of the tracks are now on the SAME relative audio level).

All I'm simply trying to say is that the soundcard manufacturers set up the "-10" inputs to match the levels coming out of the unbalanced instrument (here a JV1010). The result of this is that using a "-10" input with an unbalanced instrument, you get a "higher" audio level (measuring signal to noise) than a "+4" input with an unbalanced instrument.

The Conclusion: --> If you compare the "same" unbalanced instrument playing the "same" thing into either a "-10" input or a "+4" input, you will get a "higher/hotter" signal on the "-10" input.

E
 
Okay, here's what I did. Using the same mic, pre and pre settings, I recorded two different tracks, the first with the soundcard set at -10, the second with the soundcard set at +4. The +4 had way less hiss, listening through headphones which are *way* less sensitive than my monitors.

The -10 setting was more sensitive (ie - it required less gain from the preamp) but it had loads of hiss compared to the +10 setting, which was dead quiet.

Also: "All I'm simply trying to say is that the soundcard manufacturers set up the "-10" inputs to match the levels coming out of the unbalanced instrument"

You might be right, but that's not the idea I got from the thread I linked to above. Check it out. My understanding is that you can run either voltage through either balanced or unbalanced, it makes no difference. Balanced rejects hum better, and has little relation with signal voltage. +4 is a hotter signal (so better SNR), and runs through either balanced or unbalanced cable quite happily.
 
Oh, now I understand where he's coming from: he's talking about the raw line-level output from an instrument (say, a keyboard) being run directly into a recorder's input *with no intervening preamp* to provide make-up gain.

In that case, what he's saying does have some merit: the instrument can drive a -10dBV input to nearly full scale (0VU), whereas it will always be at least 11dB *below* full scale when driving a +4dBm input. As a result, the signal will appear 11dB "hotter" with respect to 0VU on the -10dBV gear: it'll be closer to the headroom, and it will probably appear to have roughly 11dB more level over the intrinsic noise floor of the recorder, than running the same signal into a +4dBm input with no additional make-up gain. Okay, I buy that: the VU meters are reading "volume units" with respect to that piece of gear's design reference, and not the actual voltage levels.

That's certainly true as far as it goes: the levels do match better on a -10dBV input without twisting a knob for more makeup gain.

Now, Dobro's experiences differ, but for good reason: he's talking about using a preamp to move the signal near 0VU in the +4dBm case, before he ever gets near the input to the recorder. In that case, the signal has been pushed up by 11dB over the environmental/equipment residual noise floor before it even goes into the recorder, and you'd certainly be able to say that the hotter signal _would_ be quieter.

You two are just slicing the problem in different ways. In one case, you're just using the instrument's native output, and optimizing the recording gear around that. In the other, you're using a preamp optimized for low noise to provide the additional gain to make it match your recording gear: that's something that just turning the line-in gain knob on your board probably can't quite rival.

Now that I know what context each person is referring to, I can see that _both_ are right.

However, I'd like to underscore the fact that optimizing the gain structure is one of the most important techniques in controlling noise and preserving headroom while recording. If your instrument can't drive the input levels you need it to, using a preamp that is optimized for low noise to boost the level to match the input's needs *is* the correct solution. And if you are talking about sensitivity to environmental noise (EMI/RFI, ground loop hum, opamp thermal noise hiss), then running at a +4dBm reference level absolutely will have an advantage of on the order of 11dB.

Nowadays when everything is bridging, the environmental noise voltages are really pretty much the same in both the -10 and +4 systems. The 11dB advantage is what counts, _once you've provided the makeup gain to get your signal there_. That _is_ a win in signal-to-noise.

So if you're running preampless, and making do just with the minimum gear, Rev E is right. But if you're seriously trying to squeeze every ounce of performance out of your rig that you possibly can, Dobro is right. It just depends on what you are trying to do, and what gear you have to do it with.
 
Skippy,

Yep, you got it right about the relative levels of full scale on the recorder's input.

I am well aware that it's best to put a preamp between an instrument and the input. BUT, if you read Flash's initial question he had his JV1010 plugged directly into inputs 3&4 and the Peavy mixer plugged into inputs 1&2. So my answer was basically telling him that if he was going that way the "-10" was the best input for him. Overall, I would agree that going throught the mixer was best because it would give him another stage of gain. But I was answering his direct question/issue.

E
 
You guy's are great, thanks for the help. I am finding that if I get the TRS sterio to 2 mono's that I can really start using this like I should have been. But I do have one more question about that. If I go from my insert on the mixer with the TRS cable to input 1 and output 1 on the D-Man, I still bypass the mixing board its self until the return comes back? Then where would I hook up my power amp? from the main monitors on the mixer? I Think I got it but just want to make sure.
 
Flash,

Yes, you should hook up your monitors to either the "Main Outs" or the "Monitor Outs" if your mixer has them. The Monitor Outs would be best if you have them. But the Main Outs will do if you don't.

I'm not sure what outputs are on the Peavy mixer. Perhaps you could tell us what outs exist on that mixer. On Mackie mixers, for example, there are monitor outs which can be controlled from a control room knob on the mixer. This makes things very convenient to be able to quickly turn your monitor volume up or down without the hassle of messing with the "Main" faders.
 
I have return 1 (left/mono and right) I have return 2 (same) I have aux 1 and aux 2, then I have my main outs left and right.Does this help? Oh, got my Hafler TA 1600 today. Now for the Delta 1010 and a Mackey 1604, to much.... What ya gonna do!
 
With those outputs, plug your amp into the "Main Outs". When you get your Mackie there will be a "control room out" that would be better (because you can change the volume with the control room knob without affecting the main levels)... but that's for later.

The Returns are best used for effects.
 
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