Is a pre-amp really necessary?

[justinm.]

I'm sure this is probably the most moronic question you've read on here. Maybe anywhere. I've been reading that it's a must for compressing. Thing is, when I've asked at music stores about recording vocals, etc. and having had condensers and compressors explained to me, no one has mentioned ANYTHING about a pre-amp.

[Track Rat]

Preamps can't be avoided. The signal from a mic is very low and must be amplified. They amplify the signal from a mic and bring it up to line level.

[cusebassman]

Originally Posted by justinm.

I'm sure this is probably the most moronic question you've read on here. Maybe anywhere. I've been reading that it's a must for compressing. Thing is, when I've asked at music stores about recording vocals, etc. and having had condensers and compressors explained to me, no one has mentioned ANYTHING about a pre-amp.

Trackrat got it, I'll elaborate.

Preamps and compressors technically have nothing to do with one another although you will occasionally find compressors built into a preamp, usually referred to as a "channel strip". Forgive me if you already know any of the following, I am just being thorough

Your microphone - any mic, doesn't matter if it is dynamic / condenser / ribbon / other - puts out a very low-level signal. All a preamp does is takes that signal and boosts it. Many microphone preamps have phantom power built-in in case you want to use a condenser mic, but even phantom power has nothing to do with the boosting of the mic's signal - it is simply a power supply that runs through the mic cable to any mic that needs internal power to operate. Other features such as decibel pads, phase switches, EQ, etc., are all add-ons - again, they technically have nothing to do with the amplification of the microphone's signal.

Compression is also an unrelated tool. What it does is "even out" the dynamic range of the signal coming into it - be it from a microphone preamp, a previously recorded signal, etc. It does this by reducing the level of a signal once it reaches a certain threshold. It "attenuates" or cuts the signal by a certain amount (ratio). The compressor itself is technically reducing the overall volume of the signal by squashing high-level input down closer to the lower levels of that same signal, and as such, there is a "makeup gain" knob, which boosts the overall output signal so that things are back up where you want them.

This isn't a completely clear description, so if you want to learn more about compression, search the site here - there are countless threads explaining what compression does, and even a number that give you a starting point on where and how to use it.

[Richard Monroe]

Yo Justin. Welcome to the board! OK, others have already given you the basic answer, which is yes, you absolutely need a preamp. However, there are a couple points of potential confusion left over. The first one is that many pieces of equipment, such as mixers and digital recorders *contain* preamps, so you may already have one or more preamps, and not even know it.
The second one, which is more subtle, is just *what* is the difference between cheap preamps and expensive ones? A $50 Behringer mixer contains about 8 preamps, and a bunch of other components, so you are probably payng at most, $3 per preamp. An Avalon AD2022 contains pretty much nothing but 2 preamps, and costs about $2500, or $1250 per preamp. Now if all the preamp did was increase gain, and raise the weak mic signal to line level, I could sell my Avalon, buy about 800 Behringer preamps, and sell 798 of them on ebay. Woo Hoo! And please note- the Avalon is *by no means* the most expensive preamp out there, price per channel. It is also not *the best*. There is *no* "best". It's just a color of paint.

What a preamp does involves some things that can be measured, and some things that can't. First, how much gain can it provide, and how much noise does it produce? When the gain is increased, does the signal-to-noise ratio begin to deteriorate? Secondly, how much does it distort the signal it is given? These things can be measured. Does it sound good? This cannot be measured. Guitar amps usually produce *lots* of distortion- on purpose. Microphone preamps usually produce far less distortion- on purpose. Now it could be that you really like a distorted clarinet. If so, we disagree on what sounds good. Two perfectly competent musicians, or audio engineers, can disagree on what sounds good.

Sometimes distortion, especially if it is subtle, can make things sound better, like airbrushing a picture of a centerfold. It can cover up annoying details that we don't want to hear. When we like it, we call it "warm". When we don't, we call it "muddy". One man's muddy is another man's warm. So some preamps (and mics, for that matter) produce less distortion. We call them "clean". Others produce more. We call them "colored". But it's not a black and white thing. There is every imaginible shade of grey between the two ends of the spectrum. However, we all pretty much agree that noise sucks. We don't need the preamp to produce it's own signal.

So if you own a mixer, you already own several preamps, and the odds are, they probably aren't very good ones. They probably produce quite a bit of noise, tend to distort unpleasantly when they are cranked, and produce distortion that we are more likely to call "muddy" than "warm". In most project studios, with a limited budget, we have a few channels of better preamps for those mission-critical functions, like vocals, and we have to use more mediocre pres when we need a lot of simultaneous channels (drum kits are the main channel-eater). I figure if you only can have a handful of great channels, you start with 2 pretty clean ones that are identical, for stereo recording and acoustic instruments. Later, you add one or more somewhat more colored channels to get some different crayons in your box. To start off, many people consider the M-Audio DMP-3 to be two pretty clean, very cheap channels, without a lot of noise or distortion. I occasionally use mine, which I've had for years.

In conclusion, I will say this. Your preamps, after your room, are the heart and soul of your studio. I would much rather plug a cheap mic into a great pre than an expensive mic into a bad pre. A great mic will only show off how much your pre sucks, but a great pre will show you how good a cheap mic can sound. Ask the boys here- would you rather record with a Brauner or a Schoeps mic plugged into a Behringer mixer, or an SM57 plugged into an Avalon or Martech pre? If you buy a good pre, you may never know what a good thing that was, because of all the problems you won't have. If you buy a mediocre preamp, you may find uses for it, but you'll still need a good preamp. Good luck.-Richie

[rokinrandy]

Originally Posted by justinm.

I'm sure this is probably the most moronic question you've read on here. Maybe anywhere. I've been reading that it's a must for compressing. Thing is, when I've asked at music stores about recording vocals, etc. and having had condensers and compressors explained to me, no one has mentioned ANYTHING about a pre-amp.

Whats up Justin
If youre not inquisitive you will never learn.. It's a basic question but a very important one in my opinion..

Sometimes when people have been doing something for a long time they forget to mention the most basic essentials to a novice..
The guy at the music store probably assumed way back in his mind that everyone should know about powering mics ,signals and what not..But you would think he would mention details like that especially if he wants to make more sales..

What kind of set up are you building from ?? TTYL,RR

[antispatula]

I think the preamp is definitely the heart of the studio. You can get away using a 25 dollar mic and get great results, you cannot, however use a 25 dollar preamp and get anything decent.

The combination of the mic, the preamp, and the environment you're recording in is what makes or breaks your sound. Not including engineering skill, mixing and preformance of course.

[justinm.]

Wow! Thanks you guys for all the replies. Thank you so much. I'm not on here everyday so I hadn't seen them all until just now. Everytime I check into this forum I feel quite stupid after reading everyones posts and such, I know so little about recording and the equipment needed.

rokinrandy, it's amazing how little I have when reading up on other members gear. I've got a Tascam 2488..the older version a RNC compressor which I feel I'm not getting the benefits from..and uh, you know...a couple small amps and 1 $80 live microphone, some cords...list all the little things so it looks like I've got more.

[killthepixelnow]

Originally Posted by Richard Monroe

When the gain is increased, does the signal-to-noise ratio begin to deteriorate? Secondly, how much does it distort the signal it is given? These things can be measured. Does it sound good? This cannot be measured. Guitar amps usually produce *lots* of distortion- on purpose. Microphone preamps usually produce far less distortion- on purpose. Now it could be that you really like a distorted clarinet.

That's true. But now I'm a little confused about pre's ... If, for example, I want a really heavey distortion coming from my guitar... what should I need? A preamp with a drive knob? (I.e: PreSonus BLUETUBE Preamp) Or maybe a clean preamplification and a external stomp box? What if I want to imitate the functionality of a Mesa Boogie head? Buy a preamp that allow me to crank the tubes and a power amp to amplify that sinal? Hope you can clear things out to me. Thanks in advance.

[mixsit]

Originally Posted by killthepixel

That's true. But now I'm a little confused about pre's ... If, for example, I want a really heavey distortion coming from my guitar... what should I need? A preamp with a drive knob? (I.e: PreSonus BLUETUBE Preamp) Or maybe a clean preamplification and a external stomp box? What if I want to imitate the functionality of a Mesa Boogie head? Buy a preamp that allow me to crank the tubes and a power amp to amplify that sinal? Hope you can clear things out to me. Thanks in advance.

Preamps can in some cases venture into some amounts of saturation but wouldn't typically be called on to go where guitar amps (miced), Pods, pedals and simulation plugins go.

[Richard Monroe]

Yo pixel! OK, you want heavy distortion from your guitar. Fine. But you *don't* want to get that from your mic preamp (trust me on this). So, there are several standard ways to accomplish this:

1. (the gold standard for over 50 years) Crank up a guitar amp that gives you the sound you want, stick a mic in front of it, and plug the mic into a mic preamp. Put on some headphones, and play around with mic choice, mic placement, amp settings, and guitar settings until you get the sound you want. Go by the *recorded* sound, not necessarily how it sounds in the room. Note that cheap dynamic stage mics often work very well for this, often better than high end condenser mics. Many people add another mic at a distance, called an ambient or "room" mic, and blend the two to taste. If the cab has an open back, I sometimes put another mic behind it and reverse the phase on it. I use a kick drum mic for this, 'cause open cabs blow tons of low frequencies out the back.

That is pretty much the right way, but there are some alternatives, such as:

2. Use a specialized guitar preamp, especially one that uses digital models of guitar amps, such as Line 6 Pod, Vox Tonelab, or for cheap, even Behringer VAMP II.

3. (this requires headphones and imagination) Plug the guitar directly into the high impedence (also clled high-z or instrument) input on the mic preamp, and select amp models or distortion plug-ins which are available in software, such as amp farm, and are built into most standalone digital recorders.

4. Then there's what I do, which splits the difference between #'s 1 and 2. Plug the guitar into a modeler (I use Pod Pro mostly), run the line out of the Pod to a clean amp/speaker combination (I use studio reference monitors or a Carver poweramp and a floor monitor), put a mic in front of the speaker, and send that to the mic preamp. This allows me to dial up amp and speaker models, and also to get the sound of moving air hitting a microphone, which is a big part of the electric guitar sounds we've gotten used to for over 50 years.


One trick I use is one called a "monster in a box", which I learned from Jon Chappell. I bought a heavy duty plywood shipping crate, lined it with several layers of carpet and some acoustic foam, and installed a dedicated power cable, a mic cable and a short speaker cable in it. I can put the combo amp (OK, a stack won't fit in there) , or a speaker cab in there with the mic and put it in another room so I can crank that bad boy up without waking up the cat. It won't make the amp silent, but it does take the edge off it, so the neighbors aren't calling the cops.

You should note that many amps, and Pod, for instance, allow you to record a "dry" or unprocessed guitar signal onto another track, so you can run it through different amp models or even actual guitar amps later, and play around with the sound afterwards. This is called "re-amping". It's always handy to have a dry track in addition to the main track, in case you decide you need a different sound later. Sometimes what sounded good in the beginning doesn't sit in the mix as well as you had hoped later on. Hope all this helps.-Richie

[mikeh]

Mr. Monroe,

Great posts - good information al the way around.

Your posts sparked my interest so I visted your studio web site (it is extremely rare for me to commit time to "investigate" anyone on this site).

I got a chuckle from seeing the names of your guitars - a little of an "Angel" fixation me thinks

[killthepixelnow]

Originally Posted by Richard Monroe

(...) Plug the guitar into a modeler, run the line out of the Pod to a clean amp/speaker combination , put a mic in front of the speaker, and send that to the mic preamp This allows me to dial up amp and speaker models, and also to get the sound of moving air hitting a microphone(...)

Hey, thanks for the good information. I think I understand what you're doing: using the modelers just to get the right sound and then pass it thru an amp to get the "air" and the "hit" of the waves thru the mic. Why put the tube mic preamp at last in the chain? Why not use it after the modeler and before the amp and use only the amp's power section? I'm in doubt beacuse the guitar amp has its own pre section

[mikeh]

The reason the mic pre would be last in chain is that you are using the pre to adjust the mic's signal - so the pre has to be after the mic.

[Richard Monroe]

Yo Mikeh! Thanks for your kind words. I'm sorry the pictures aren't up to date. I've added a Strat (no-brainer).

Yo Pixel! You're not quite clear on the concept, but you are getting there. Let's review some terms:

preamp- an amp that raises the weak signal of a mic or instrument to line level

power amp- an amp that raises line level to something strong enough to drive a speaker

A guitar amp is a preamp and a power amp designed to accept an insrument input. If it has a built-in speaker, we call it a "combo" amp. Some guitar amps are just amps, and plug into one or more "cabs" or cabinets, each of which contains one or more speakers.

A mixer is a bunch of preamps with options for sending multiple signals to one or more outputs, called "busses". Some mixers also contain one or more power amps. These are called "powered" mixers.

Speakers can be "active/powered" (containing a power amp), or "passive" (need a separate power amp).

So a PA could use a powered mixer and passive speakers, or a passive mixer and active speakers.

In the guitar setup I described above, there is no guitar amp involved, exactly. I use the Pod/Vamp as a preamp. It produces a line level signal. But- I want to use microphones, to record the impact of moving air. So, I need a power amp to drive one or more speakers. I use a specialized power amp (not a guitar amp) that was designed to drive (passive) studio monitors. That power amp drives a speaker cabinet. Then I put up mics, and our signal is back down to that weak mic level, which needs to be raised back to line level so it can go to a recorder or interface. This requires a mic preamp.

The selection of the power amp/speaker combination is critical. The Pod contains a "speaker model" which attempts to recreate the sound of various types of cabinets when mic'd up. This is called "studio mode". Fortunately, I can turn off the speaker simulation . This is called "live mode". This is intendes for a person who is sending the Pod's signal to a big mucking power amp or PA head, and then to one or more speaker cabs, on stage. This is kind of like what I do, on a larger scale.

The difference is- if I send the signal from the pod to a guitar amp, or a guitar speaker, it will add its own character to the signal. What I want is a broad spectrum amp and broad spectrum speakers that produce damn little noise, and simply reproduce the sound the preamp gives them, without adding their own character. I want an amp and speaker that can produce bass, or treble, without adding, subtracting, distorting, or modifying the signal. This is what we call "flat" response.

A small PA works pretty well for this, but makes more noise than is ideal for recording. So first, I got a power amp, in this case, a Carver PM125. Small amps are good for this, because they produce less heat than big stage power amps, therefore don't need fans, and are therefore quieter. Also, amps made for driving studio monitors generally make damned little noise. OK, so I could plug the power amp into, say, a Marshall cab with a Celestion vintage 30, greenback, or whatever. Then I disable the cab simulation, and I will get the sound of a 1X12 Marxhall cab with a Celestion vintage 30, which could be OK. But- what I want is to be able to use that cab model *and* a real cab I can put a mic in front of. For broad spectrum speakers, I got much better results by switching to PA speakers. Problem was, the PA cabs contain different kinds of speakers with different frequency ranges. Mic placement became a pain in the ass. Then I switched to a 10" Fender wedge monitor, which *is perfect*. For anybody planning on doing this, make sure your power amp is bridgable to 8 ohms, it'll drive the 8 ohm monitor much better than the 4 ohms that most studio reference monitors are looking for.

Finally, I plugged the line out of the Pod into the line in of a powered studio reference monitor, and mic'd that. That rocks, but I haven't yet come up with the coin to buy a really good monitor for a dedicated recording amp, and switching all the inputs and outputs so I can listen to what I did is a pain in the ass, so mostly I just use the Carver and the wedge monitor. I also find that because the whole setup is smaller/quieter than a cranked up combo amp, even with distortion, I get better results using condenser mics than the dynamics I would put in front of a loud amp. I've tried a lot of mics, including some expensive models, but keep coming back to AKG C2000B, a basic $150-$200 small diaphragm con=denser. It has repeatedly beat out everything from Neumann KM184 to B.L.U.E. Kiwi to AKG C414B-ULS to Shure SM-7. Beats the hell out of me. What I really want to do is find a deal on just one really good powered monitor, put that in the isolation box, and try that. That should be really quiet, but trick the recorder into believing I've got a cranked up amp.

So what do I get for all this? Sound from a modeler that doesn't suck, at a volume level that bothers *nobody*. It allows the amp model to be reproduced much more faithfully, and can sound shockingly like the real thing. Don't want the pain in the ass? Go back to plan A. Get an amp that sounds good, crank the crap out of it in a good room, put a good stage mic in front of it, and send the signal to the best mic preamp you can afford.

Oh yeah- you said "tube" mic preamp. There are *no* tubes in my Avalon. Note that preamps with or without tubes can be clean or colored, Some tube amps produce almost no distortion. Some solid state amps produce plenty. If you want a lot of distortion, as in a guitar amp, tubes are often preferred. Note that most "tube" preamps don't really have tubes in their power section, just a little tube in the preamp section. Mostly, this is marketing BS, so they can call it a "tube" amp. Good mic preamps that are really powered by tubes don't come cheap, as a rule. Some of the gratest recordings of all time have been made with both types. Keep it coming, Pixel. You'll get it. It's not rocket science.-Richie

[killthepixelnow]

Originally Posted by Richard Monroe

Finally, I plugged the line out of the Pod into the line in of a powered studio reference monitor, and mic'd that. That rocks, but I haven't yet come up with the coin to buy a really good monitor for a dedicated recording amp, and switching all the inputs and outputs so I can listen to what I did is a pain in the ass, so mostly I just use the Carver and the wedge monitor.

After reding the post twice I'm starting to get the chain you're using. You didn't mention the power amp in your other post, but now it seems clear. Er... are you miking a powererd near-field monitor (like the ones I have in my house)? Or is a passive one driven by the power amp section?

PS: Have youe ver tried the ART Tube MP Project Microphone Preamp?

[Richard Monroe]

Nope, never tried the ART MP. I did, however, mention the power amp. Read again-

"4. Then there's what I do, which splits the difference between #'s 1 and 2. Plug the guitar into a modeler (I use Pod Pro mostly), run the line out of the Pod to a clean amp/speaker combination (I use studio reference monitors or ***a Carver poweramp*** and a floor monitor), put a mic in front of the speaker, and send that to the mic preamp. This allows me to dial up amp and speaker models, and also to get the sound of moving air hitting a microphone, which is a big part of the electric guitar sounds we've gotten used to for over 50 years."


My monitors are powered. Actually, I use M-Audio SP5B's and an M-Audio SBX subwoofer. When I use them for the above application, I use the sub and one of the satellites. When I used both SP5B's, I got phase distortion issues, making mic placement critical. I found it easier with the sub and one monitor. The SP5B was made to work with a subwoofer, and produces too little bass by itself for the job. When I get that one powered monitor, it'll have a better bass driver, and I won't need the sub.-Richie

[Sinistah]

Originally Posted by justinm.

Wow! Thanks you guys for all the replies. Thank you so much. I'm not on here everyday so I hadn't seen them all until just now. Everytime I check into this forum I feel quite stupid after reading everyones posts and such, I know so little about recording and the equipment needed.

rokinrandy, it's amazing how little I have when reading up on other members gear. I've got a Tascam 2488..the older version a RNC compressor which I feel I'm not getting the benefits from..and uh, you know...a couple small amps and 1 $80 live microphone, some cords...list all the little things so it looks like I've got more.

i used to feel the same way, until i started to read up on things a lil more and then not even a full month ago i decided to join the board......everytime i log on i learn something new thanks to the community....

[mikeh]

I own an Art Tube MP (actually two) which I've had for several years. I bought the 1st one when I first decided to use an outboard pre (vs. my mixer) and I bought the 2nd when it was at a blow-out clearence at a local store.

I don't really use them anymore (I've upgraded to better pres). They are low end units (maybe comparible to the low end M-Audio pres) - but based on your level of experiance and the equipment you have, an Art Tube MP would not be a bad low cost option to get you started (in particular if you are focusing a mic used to mic a guitar cab.

[killthepixelnow]

Originally Posted by mikeh

(I've upgraded to better pres)

What are you using now? Avalon?

[mikeh]

OK, you caught me

I've upgraded to slightly better pres (Focusrite & Presonus).

[killthepixelnow]

I'm saving to get a decent preamp. Art Tube does the job but, as Richard stated before: buy cheap, sound cheap.

[irkir]

yep, makes the sound louder w/o a lot of background noise--plus you can warm the sound up

[Richard Monroe]

Actually, I never said "buy cheap, sound cheap". You'll notice I said I have a DMP-3 and still use it, occasionally. Don't mistake me for a gear snob, I'm not one. First, if I was, I wouldn't be plugging a Pod into a boogered-up signal chain, because I would actually own the pricey vintage tube amps that I am digitally modeling. What I actually use is an Avalon AD2022, a Joemeek twinQ, an M-Audio DMP-3, the onboard preamps in a Digi002, and, believe it or not, a Behringer ADA8000. OK, 95% of all stuff goes through the Avalon or the Joemeek, but when I need a bunch of channels, I use all kinds of cheap stuff.

If I *had* commented on the price of gear, I probably would have said 2 things. First, it is harder to get good sound out of cheap gear than expensive gear. And second, in spite of what the financially challenged and envious will tell you, you can learn to record things just as well with expensive gear as you can with cheap gear. I did say that owning a good preamp will prevent a lot of problems, and it's true. I have absolutely never regretted buying that Avalon. But what the hell? I'm 53 years old, work a regular day job, and I made a living for 12 of those years with bad guitars, cheap PA's, lousy mics, and bad amps. I've paid enough dues that I can afford a good mic pre. My mommy didn't buy it for my birthday.

The important thing is that whatever your budget for recording gear is, the mic pre(s) are mission critical. They are not an afterthought, but perhaps the single most important piece of gear you will buy, after your instruments. Inexperienced homerec'ers usually think about the signal chain from the back forward, but audio engineers almost always think of it from the front back. If you have a good song, played on a good instrument, in a good room, *****by a good musician******, captured by the right mic (not necessarily the most expensive mic) in the right place, plugged into a good preamp, you can record it on a SONY cassette Walkman and it will sound pretty damn good. Garbage in-Garbage out. Your preamp is a huge part of whether you are capturing and translating all that good stuff, or just shoving a wad of cotton batting into the lead singer's mouth.

You can make good recordings with cheap gear, and everybody has to start somewhere. But if I were building on a budget, I'd put a big part of my money into my room and my preamp, regardless of how big or small that budget was.-Richie

[Sir_Matthew]

This will be an unpopular opinion, but...

I find that I get perfectly good signal plugging mics directly into my ProTools Digi 002 Rack. I used an ART Tube MP back when I was using a Roland VS-880, but honestly, upon hearing the mics direct, I found the MP was bunging up the signal a bit.

Now, this is not to say that a good pre won't improve the signal. It absolutely will, and I've heard that in higher-end studios than mine. But if you can't afford a very good pre (which I can't), you can still get what I at least consider to be a perfectly good sound by plugging a decent mic (in my case, an Audio Technica 4040) into a decent board. And you may end up doing damage to your signal if you use a cheap or even mid-priced pre.

This is just my experience, but I'll go hide in a cave now as the hail of stones begins...

[mixsit]

Originally Posted by Sir_Matthew

This will be an unpopular opinion, but...

Not at all. Case in point, before I got some nice pre options I ran my QTC-1s for a few years with nothing but a phantom box and a pair of splitters (monitor split) and still ran in-line attenuators in some cases to dump voltage.
The output impedance is low enough, the input is high...
...No worries.