A lot of people see vocals as the most important part of a song or performance. After all they tell the story, they communicate the artists vision, emotion and intent in a way that's unique from most other instruments.
The Jimi Hendrix guitar solo of the National Anthem was legendary. His screaming guitar solos moved more than one generation and gave the guitar a special place in pop culture.
Lets look at the guitar for a minute. There are so many different styles of guitars, electric, acoustic, so many types of pickups, strings, you get the idea. Now add an amp or microphone a few pedals or effects and processing. Consider all the variation that are introduced and shape the sound we hear. There are so many different guitar sounds that we do not recognize one as sounding unnatural.
We hear the voice all the time. We all can tell right away when a vocal does not sound natural.
Professionally processed vocals have clarity, a wide frequency content, and a dynamic range that allows for the emotion of the voice to come through and sit nicely in a mix.
When you process a voice or instrument, either by tweaking that EQ, or adding an effect, or adjusting the level, you color that sound. Processing changes it and distorts the wave form. It changes it from a naturally produced one to processed one. With an instrument, it goes mostly unnoticed, changes in a vocal, even a little bit can stick out like a sore thumb.
Are vocals processed? Yes, an experienced engineer has the tools and the knowledge to correct minor flaws, they can transparently enhance the vocal, bring out the emotion and place it in the best space in a mix. These changes are very subtle and do not change it in a way that sounds unnatural.
Crank that EQ on a guitar and it sounds different, crank that EQ on a vocal and it can sound bad.
Are vocals more difficult to reproduce? Most engineers agree that the answer is yes. It takes an in-depth knowledge and years of experience dealing with frequencies, space, processing, and the ability to get everything in the mix to work together.
Determining whether an engineer has this knowledge and experience can be difficult, particularly for someone new to the recording process. The one thing you can determine is the quality of the studios gear.
There are many bloggers who go into great detail, explaining how to get professional results on that $100.00 microphone or $200.00 pre amp.
This grade of gear simply cannot reproduce the frequencies needed to accurately translate the human voice into something that sounds natural. The truth is most of these bloggers are attempting to sell their content or gear from their sponsors who pay them money to do so.
This is where a Record Producer can be invaluable.
But not all struggling recording artists can afford these services, so what do you do.
Get a list of the gear the studio uses, look it up, how much does it cost? Check out the reviews on the gear. Do professionals use this gear. It requires some research but after all the time you spent developing your talent and your material it would be a shame to record it in a studio that uses less than professional gear.
George Martin used the U47 microphone when he recorded the Beatles. It was cheaper back then but today they cost around $9,000.00. I've seen pre amps go for as much as $45,000. The bottom line is quality gear isn't cheap and good microphones, preamps, compressors and effects can run into thousands of dollars. Make no mistake they are required if you want a quality recording.
You should also ask for samples of the studios work and take it out of there environment. listen to it in your car, your portable device, does it sound like other professional recordings, do your homework. A little time spent here can be the difference between a great sounding recording and a mediocre one.
After all, the quality of the finished product can make or break your project.