To Pre or Not to Pre

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Dot

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I want to thank this community. This article I've written that was just published today started as a rant in this forum. It's been tweaked a bit since then. I hope you like it and gain something from it.

To Pre or Not to Pre, Quality pres can focus sounds in your mix and give everything better definition

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Dan Richards
Digital Pro Sound
 
must be a wavelength thing...

Dot, this is awesome...

I swear... I'm on the same wavelength as a lot of people this week...

https://homerecording.com/bbs/showthread.php?s=&threadid=69051

Check my reply (the long one) to GONZO-X in the mp3 clinic... posted 2 hours before yours :eek: I SWEAR I just read about this very thing on mercenary audio yesterday... and it's very true.

This is from that thread:

(please clue me in when it seems I've lost it ;))

cheap pre's & non-musical distortion

...Apparently, cheap pre's distort the signal in an "unmusical" way, causing stacked tracks to sound "unfocused". This happened with J-Station trax on my rock tune.... could be described as "blurry". You could be using a good mic (SM57), but the low-level odd-harmonics (11ths, 13ths, etc) in the track which you probably couldn't hear soloed would just end up sounding really cloudy after a few trax are added.

I just tried mic'ing an amp with a self-powered Rode NTK last night, adding only about 10db of gain with the pre-amp, and it was a major difference. The tracks dang near mixed themselves!

----

Now, is that information technically right? Isn't the distortion caused by cheap pre's (at low levels) what clouds up mixes, esp. when tracks are layered? Could it be analogous to some kind of low-level dissonance, even, since we're talking about odd-harmonics like 9ths, 11ths, etc?

Seems like there'd be a way to measure how much a certain preamp distorts (colors) a signal, to know when you're driving it too hard... (or driving it to distort "unmusically")

Please feel free to jump in at any moment and declare what I'm guessing at as "total crap" :p


Thanks!


Chad
 
Great Article! Great Listening Tests!

I downloaded all the files and am studying the guitar ones right now. It sure would be nice if I had a set of monitors to listen through instead of these crappy headphones, but I can tell differences although some are VERY subtle (at least through these crappy headphones).
Very informative though, thanks!

Mike

P.S. Is there a problem with the acoustic run through the Oram? It didn't download and I tried it twice.
 
Hey Dot (Dan),

Do you know of any software tools that could "graph out" the space a track takes up in the stereo field? For instance, in the article you talk about how the sound of a guitar thru a cheap pre could be compared to the size of a quarter, and thru a good pre it's the size of the head of a pin.

Theorhetically, it should be possible to graph that out somehow visually. Might Waves make something to that effect? Seems like we should be able to measure/quantify these things... could help a few of us "tune our ears".

Seems like such a plug-in would show the "cheap pre" track as being a fuzzy, undefined area... and the other as sharply defined, much more focused.

If there's not such a plug-in, maybe there should be.


Chad
 
So all these a/b/c listening tests we've been doing on the various pres out there are really pretty useless when you boil it all down.

The only way to know if a pre is any damn good is to hear how it holds it's own as other tracks are added in and stacked up.

I coulda' told you that. :D :D
 
Its always been my opinion that clean pres go on everything but voices. The right voices may even benifit from a clean pre, but Ive yet to hear one.
 
Re: must be a wavelength thing...

participant said:
Now, is that information technically right? Isn't the distortion caused by cheap pre's (at low levels) what clouds up mixes, esp. when tracks are layered?
Click to expand...

I'm really interested in what you're saying here, Participant.

The only thing I'd like to ad is that the distortion specs/figures of even the cheapest pres on the market seem to be so low so as to be insignificant.

Mackie: distortion under 0.0007% (20Hz-20kHz)

M-Audio: THD + N: .002% @ 1kHz

ART Tube MP: <0.1% (typical)

I'm not really much the techie type, here, so I don't know for sure if these specs are good or not, but they seem awful low to my uneducated brain.
 
Dot--I am somewhat confused by your theory. I'm not disagreeing with you at all, but you say that a hi end mic pre is like a pinhead in the space of a mix, while a cheap pre is blurry and eats up more space. It makes it sound like the cheaper pre's have a broader frequency reproduction. Isn't that what fills up sonic space? If the hi end pre is more like a pinhead, then it seems like it would be focused on a narrower band of frequencies. Am I not understanding something here?

Chessrock's comments about the low distortion specs on things like the Mackie pre's also make me wonder if its the distortion or something else.

Heck, I don't own a hi end mic pre yet. I imagine when I do have one, all this theory will make perfect sense to my ears! Again, I am not in disagreement with what you are saying, I'm just not understanding the principles too well.
So, whassup with this? :D
 
When you look at a sine wave, a nice pure sound will make a clean looking wave, but with a colored pre you will start to get humps on that wave, which sounds good if that wave is the only one, but if you have alot of waves going with alot of overtones you end up with shit. which is why you want to only color the vocal because overtones make voices.
 
people always forget behavior when they talk about this stuff. Its important to remember that almost every device is also a compressor. Mic pre's, mic's, EQ's, tape recorders, converters etc...are ALL also compressors. They behave different ways depending on how much signal is given to them. Not just in distortion either. Even more complicated, all these devices are even more importantly MULTI band compressors, and treat different frequencies in different ways.

CLEAN mic pre's by themselves arent the answer. Go track an album thru an SSL or Mitsubishi console ( REALLY REALLY CLEAN mic pre's "technically" ) and see if you like it. Its important to find out exactly WHAT you are turning up when you crank that mic pre gain. The trick is using the pre that accents the stuff you want and doesnt amplify the stuff you dont want.

A great analogy is a guitar power amp. These are completely non linear, and certainly not FLAT devices. They boost and compress mostly midrange, without pushing up the extreme hi's and lows that guitars dont make anyway
 
pipeline... understood. Pre's that compliment the sound... a relatively "clean" pre wouldn't compress/add harmonics to the sound (very much), and a pre with coloration would both compress and add pleasing, musical type harmonics to the tone (e.g. adding low level overtones like 2kHz, 4kHz to a 1kHz tone...)

crawdad... I'm thinking the head of a pin/quarter analogy is a relative measurement... when you throw the fader up on your "pin head" track (oooh.... that came out funny, did't it :D) it would grow/shrink from pin-head size proportional to the fader level. If you could visualize it, the "outline" would be relatively smooth at any size(level).

The fuzzyness/blurriness (as is my understanding, so far) is both what darrin & pipeline say... harmonic distortion and compression. A pure 1kHz sine wave would have some low level non-musical harmonics in a hypothetical "cheap" pre.

These non-musical overtones (if that's really what they are) could then be described as a form of dissonance, couldn't they? (A simple triad chord sounds much clearer than something like a I,II,III,VI for example)

Anyway, this is what I was trying to clarify... if it's wrong... someone please shoot it down quick :)


Chad
 
pipelineaudio said:
Even more complicated, all these devices are even more importantly MULTI band compressors, and treat different frequencies in different ways.
Click to expand...

This is all starting to make a little more sense. I've been noticing lately how multiband compression essentially helps a given track stay within it's own space in a mix from a sonic standpoint. Kind of gives it some boundaries, for lack of a better analogy. Much how Dot described the idea of certain pres helping a track hog up less sonic space; leaving more room for additional tracks without cluttering things up too badly, etc

Interesting how the phenomenon Dot is describing sounds an awful lot like multiband compression.
 
its kind of a tip of the iceberg thing too. I mean, lets say the part of the sound you want, is the very tiny part of the iceberg that sticks out. Under the water is more of the good stuff but also all sorts of crap too. A clean pre would raise the whole iceberg, exposing the good and the bad. The " right " pre, would raise only the good parts, and mostly keep the ugly stuff out of focus.
stretching analogy to be sure, but ...

A few studios ago, I had one of my favorite engineers in recording an album. It was to be mixed on an older Neve with a not so powerful EQ. To my horror he started plugging in all different flavors of Neve mic pre's and Trident and other " fat" mic pre's for tracking. It always seemed like suicide for me mixtime, to be using " fat" mic pre's and then mixing on a neve, mud and distortion city. But it worked out fine for him. Perfect. He just matched the right pre's to the right sources. It redefined my sense of " fat ". As the fat was actually very targeted once you got to know the peices.
 
pipelineaudio said:
It always seemed like suicide for me mixtime, to be using " fat" mic pre's and then mixing on a neve, mud and distortion city. But it worked out fine for him.
Click to expand...

. . . Which is what it all boils down to, eh?

In practice, it seems to work well enough for them (guys like your engineer), but in theory it just seems kinda' backwards to me. I would want to get a good, solid, balls-on accurate tone to tape (or hard drive), and then worry about adding distortion come compression time. It just seems like good compressors do a better job of fattening a tone; that's kind of what they're there for in the firstplace . . . only in another way (dynamically speaking as opposed to tonally speaking). :D
 
Don't wanna rain on the parade, but this sounds like voodoo to me. Makes sense on the first pass, but then start thinking and the brakes start squealing

I've now got a 1NV, and it is everything I hoped it would be...and then some.

But let's just say that a track through takes up 'way more' sonic space than a 'pinhead'. Yes it's focused, but it's also BIG. Could stuff three Mackie tracks in there. And that isn't just smoke and mirrors. The NV takes a big chunck out. But it is superb.

I don't think that cost of a preamp, plays into the soundscape size at all. Mackie takes a tiny bite out, is relatively focused, and is small. You don't need big bucks for BIG either. The Blue Tube sucks, but if you want your soundscape devoured, it'll do the trick.

Transformers and tubes in the more pricey stuff do act like compressors--so maybe that's where the focus and snugness come in. I'm not an EE though.

-Jett
 
Its not that mic pres are necessarily "bigger" than each other. And it doesnt matter whether its transformers or tubes to have this effect. Most pre's seem to have a certain area where they push hardest. The ones we call " fat" push the lower mids hardest. For guitar, toms and other things thats great, for some others it wont be
 
to illustrate the concept

Would this illustration explain the concept better, Dan?

(forgive me; I'm a visual thinker)
 

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Seems to me what he's saying....

I just have a hunch that it's bunk.

-Jet
 
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