Post-preamp, pre-converter ATTENUATOR

Posted: Sun Jun 15, 2008 1:09 pm

If it takes the lowest gain setting & turning on the pad to prevent front-end clipping, THAT'S WHAT YOU DO. YOU DON'T HAVE TO WORRY ABOUT UNDERRECORDING IN DIGITAL MULTI-TRACK RECORDING. Especially if you record at 24-bit as opposed to 16 bit (I generally record at 16-bit because I know how to). No reason to pump up those levels that high. That's the beauty of digital recording! My last console had inputs very similar to what you indicate. I had my choice of +15, +20, +35 gain settings, which were additive so you can have up to 70 DB of gain & -20 & -30DB pads, along with a slight inconsequential trim of 2, 5 or 10 DB settings. I never had any overloads only wonderful sounds coming from the old Sphere Eclipse C, tracking into the analog Ampex MM 1200-24 or the tascam da-88's. So banging meters was just something we did to analog machines on drum tracks and/or guitars on occasion since they were so bandwidth limited to begin with.

As to your summation that you believe you need another post preamp?? That's idiotic. You may think you need something like that but you certainly don't. You just need to understand your equipment better and how to use it properly. Which you are obviously not doing.

Getting an additional preamp will only make matters worse. Much worse. You have no understanding of proper gain staging. That's your only problem. A huge problem since many people have trouble understanding the concept of the boost & losses from one circuit to the next. So believe it or not, generally the rule of thumb for setting level for microphone preamps is: if you're using a standardized console, you would push your fader up to its "nominal" gain position or 0. You would then dial in some gain on the trim. If the levels are too hot? Engage the pad. Leave your output control at its nominal gain position as indicated by the 0, which is two thirds of the way up. That fader should not be any lower. It's a juggle between gain and pad, without raising or lowering your output levels from zero nominal level position.

You don't have to believe me, I've only been doing this for over 37 years and have built more than 7 control rooms, for NBC-TV & radio, Hallmark Films & Recordings, Golnick International Advertising & Marketing & others. Not to mention 3 separate installs and reconfiguration's of my studios which have included large-format Auditronic's 501's, Sphere Eclipse C & custom 36 input NBC Neve. So think what you want. Not sure why you're asking questions since you seem to already know what's wrong? You don't.

Delivering quality audio for over 37 years
Ms. Remy Ann David

Does that answer your questions?
Ms. Remy Ann David

Posted: Sun Jun 15, 2008 1:20 pm

i think there is a massive disconnect in the language being used...i didnt mean to infer in any way using ANOTHER preamp. if that is what i said, then obviously my lack of knowledge on the vernacular of the audio world is sorely understudied. im not trying to invoke your wrath Smile

so my drummer is starting to do his thing as i type this, and im now recording him with my gain knob all the way down, the trim at 0. i also pulled my bass drum mic way way lower also.

it looks like nothing is ever hitting more than about -8, that being the biggest transient thus far in about 5 minutes of his spastic hard drumming.

Posted: Sun Jun 15, 2008 1:27 pm

http://i27.photobucket.com/albums/c173/jprumers/untitled.jpg

this is what just happened....i am assuming those really fast spike lines are the transients or whatever? so in that fact, i was always clipping out the transients...?

Posted: Sun Jun 15, 2008 2:41 pm

What is that spike? Kick, snare, hat, screams?

Posted: Sun Jun 15, 2008 3:07 pm

There is nothing in your screen capture that would indicate you've clipped anything. It looks like a normal waveform of percussion instruments. What makes you think your clipped? What seems to be the problem? You want to post an example of what this sounds like? If it's clipped, it's clipped in your microphone preamp and not going into your computer. This has to do with proper interfacing & gain staging. Now if you zoom into those spikes down to the sample and observe flattopped waveforms that are not 100% excursion, you are overloading your preamp.

If on the other hand the spikes appear to go more than full-scale in the display and you find those are flattopped, you are overloading your analog to digital converter.

If you just think those spikes are clips, you don't know what you're looking at. You're looking at waveforms and waveforms look like that depending on what instruments you are recording.

Time to pick up a book
Ms. Remy Ann David

Posted: Sun Jun 15, 2008 4:58 pm

i was not under the impression that those waveforms are clipped...the screenshot i posted was the first time i tried recording with my gain knob all the way down and the trim to unity. so this essentially was the first time ive recorded my drummer without driving the preamps and ignoring the fact that those spikes were definately going "off the chart" so to speak..clipping. when i get home i can certainly post screenshots of older projects and you'd probably soil yourself...

and those spikes would be the snare 80% of the time, or maybe all the time, because i think when he hits the cymbals really hard it may have a snare hit at the same time <shrug>

i think that the main issue here that i am having is simply realizing that loud drums are SUPPOSED to be recorded with the lowest gain settings i can have... the -20 pad engaged and no gain, only trim at unity...while i have read many books, ive never come across any reading thus far that would have lead me to believe that its actually normal to not put any gain on my mics.

so this leads to another question i guess....is it simply the fact that these are loud drums (the reason why i dont need to use the gain knob)? say if i were to just do an acoustic guitar, i would likely be able to/want to begin applying gain in a situation like that?

Posted: Sun Jun 15, 2008 5:25 pm

correct

I would say these drums are very normal
and
it is normal to have the PAD engaged and to have little gain on POP and Rock drums

an acoustic guitar will require more gain

even more gain for spoken word at distance

A Drama shoot in a studio may use as much as 60 to 70db of gain
the mic pres and mics need to be the real deal then

IF you go back to the books of the 70's and 80's you should find references to drum recording on VU meters that hardly get the needle moving

these days you have the dBFS and margin indicators

Posted: Sun Jun 15, 2008 7:40 pm

And so you are golden! Just like Kev, said. Your waveform looks absolutely totally normal. 80% Snare drum? Where's the bass drum? That's the trouble, you're not seeing all the drums. You should see as much bass drum as snare drum. At least in my mixes you do. But then, I really like a big kick... In the ass. Of one sort or another.

Yeah, pad on. Low gain. Especially with condenser microphones or those dynamics with neodymium magnets. Those are hot output microphones and on drums produce nearly line level outputs! In fact, some older microphones like older Neumann tube and/or transistor microphones have built in pads to knock down the output before it sees a microphone preamp. Even some of those DPA microphones better known as B. & K. scientific microphones were produced that were line level outputs. Also capable of accepting sound pressure levels of up to 148 DB! So they could measure the loudness level of ordinance exploding or jet airplanes engine noise. I had a couple of those for a while and they weighed 20 pounds each! They were not fit onto microphone stands but had been fitted atop telephone poles and were outdoor weatherproofed. They replaced the weatherproofed capsules regularly since they were for scientific & military use and measurement.

So not to worry any you're doing well.
Ms. Remy Ann David

Posted: Sun Jun 15, 2008 11:01 pm

well the d112 is the bottom track...and the preamp im using for that is like a 5 channel shure mixer that is super old...just has inputs and ONE output so i only use one of the channels, and the only knob at all is a volume knob, for each channel, and then a master volume knob...i suspect this "mixer" has some sort of limiting or compression because if you look at it (track labeled d112, obviously) it always has the same "velocities" or peaks.

Posted: Mon Jun 16, 2008 1:29 am

okay so this is the result i came out with...

http://www.megaupload.com/?d=NRCX24TB

just enter the letters and click download theres no gimmicks with megaupload but it may seem that way if you're unfamiliar with it...and as far as the filename is concerned, please understand it was just a way to label it...mindtag it, if you will...

i just did d112 thru Q10 (waves) and RComp (rennaisance), and then group channeled the 2 NT5's thru Q10 and RComp as well, then they all go thru L1 Ultramaximizer on the output channel....for better or for worse, i dont know a whole lot about what im doing Razz

but it did seem like i had an easier time with the compression and EQ'ing...something like more headroom <shrug> lol

-Jakob

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