Mic Preamp: should I or shouldn't I?

[oneartist]

Another way to get some outstanding preamps is to keep an eye out for some discontinued mixers, especially digital mixers. Some preamps from very expensive high end mixers wind up in much smaller mixers of the same brand. they become discontinued for various reasons. Sometimes, the preamps are worth the price of the severly reduced gear.

[Gazzamundo]

Some days I think I've almost convinced myself I don't need one...

I'll maybe hold tight at the moment, and as you suggest, keep an eye out for an end-of-line bargain. Maybe I'll forget I ever thought about getting one?

Of course, if something does land in my lap, I'll let you know what it is and how I get on with it!

[ukejon]

I'm dealing with a similar problem. My equipment is not great (Shure KSM 137 and Blue Baby Bottle mics, M-Audio Fast Track Pro preamp/interface) and I'm wondering if a better interface or a pre that bypasses the M-Audio pres would help give me cleaner and quieter recordings. As it is, I feel like the gain needs to be set too high, which can't be helping with overall noise in the recording.

[Fran Guidry]

Sounds like you're in the third stage of learning about home recording:

Stage 1: What stuff do I need?
Stage 2: How do I work this stuff?
Stage 3: Why are my recordings so quiet?

As a first guess, I suspect that you're trying to get your recordings to be as loud a the commercial CDs you're comparing. This is a totally common issue, made worse by lots of bad advice on the internet regarding level setting.

The thing to understand is that the commercial tracks were not that loud when they were recorded. The level was raised in both the mixing and mastering steps. For optimum audio quality, it's very useful to aim for average levels between -18 dBFS and -24 dBFS, with peaks not to exceed -6 to -8 dBFS. This is roughly the same as the old 0 dBVU from analog tape days, and the optimum level for all our analog stages.

Your idea that a different preamp would allow you to use less gain misses the meaning of gain. The level of your recording is determined by the source loudness as measured at the mic + overall system sensitivity. Overall system sensitivity is the sum (sorta) of mic sensitivity, preamp gain, preamp output level, and a/d input sensitivity. So it doesn't matter what mic pre you use, it will have to deliver the same gain to reach the same level if the other factors remain the same.

Perhaps you're looking for a quieter preamp section than the one in your Fastrack pro. This is _possible_ but in my experience unlikely. The performance of very inexpensive chip based preamps is amazingly high these days and in nearly all home recording situations the preamp noise is much much lower than and totally swamped by the ambient noise in the room.

Fran

[ukejon]

Thanks Fran. Good advice. I think you are right on the mark about the not-so-subtle influence of ambient room noise. And I'll try those levels that you suggest. In GarageBand, do I then just crank the output volume when creating the finished track?

One local sound guy suggested getting a wall wart for the FastTrack Pro instead of using the USB connection. Do you think that would do anything beneficial?

[Fran Guidry]

The wall wart will make a difference if there's a problem in the power supply circuitry related to the USB powered side of things. I have no idea if such a problem exists either in the Fastrack pro or in USB powered interfaces in general.

I can't speak to Garage Band specifically, but the steps for processing after tracking are pretty similar in any environment. The post-production process is described in Doug Young's "Anatomy" thread http://www.acousticguitarforum.com/f...d.php?t=237148 .

In the mixing stage it's common to look for brief instances of high volume that can be reduced either by hand editing or by use of a limiter. These might be notes played a bit too hard, or squeaks or thumps. Once these peaks have been pulled down, you can raise the overall level of the track by just turning up the digital gain (raising the track or master volume). Use of EQ contributes as well, it's often common to pull down some of the low frequencies because they are overemphasized by close miking (proximity effect) and by small rooms. Once again, after you've reduced these areas you have extra headroom to raise your level.

After the mixing stage (dynamic range control, EQ, reverb, etc.) comes mastering. In "real" recording this is done by a separate engineer, who provides quality control, level adjustment, fade in and out tweaks, EQ refinement for translation to different playback systems, and loudness adjustment along with a correctly formatted industry standard master copy. This loudness tweak is the one that's most obvious to our ears, and the tool for this job is a high quality look-ahead limiter, preferably applied by someone with lots of experience and a world class monitor setup. It's probably better for most of us doing our own mastering to shoot for less loudness, especially if we're comparing to a "modern" recording with crushed dynamic range.

Fran

[dmoss74]

i'm sorry for not reading all the posts to date, but i read your gear in your op. what i would recommend is getting a grace 101. it is a very nice, moderately priced mic pre that will make a difference (read:improvement) in any signal chain.

[ukejon]

Thanks again Fran. As you well know, the nice thing about recording solo instrumentals is that dynamics really can be a good thing. Compression and limiting is definitely a fine art and dangerous in the hands of recording amateurs like me. Certainly it needs to be used very judiciously on acoustic guitar and uke (my other instrument). Didn't know that small rooms accented low-end noise, which I always have to EQ down. I've been doing some recordings in a closet with rugs on the walls, ceiling, and floor. My biggest recording problem is living right along the shore of Lake Michigan, which is noisy! That surf will cut into any recording except on the most still days. Its like a low-end hum.

As for the wall wart, the guy who suggested it (who is a good sound engineer) said that it might help a little bit (meaning I won't have to crank the gain on the mic pre-amp so much). I'll try it and report back....

[Doug Young]

Originally Posted by ukejon

TDidn't know that small rooms accented low-end noise, which I always have to EQ down.

I don't think Fran meant low end *noise*, particularly. If you have a lot of low end noise, and it isn't 60 Hz hum, it's probably just environmental noise. For most people, it's traffic, airplanes, refrigerators, etc, but you seem to have your own special noise source. Besides the high frequency surf sound, I assume there's a lot of low end that comes with it. You could figure out if the noise is coming from your preamp or your environment by using a null terminator instead of a mic. Just a resistor across a mic plug. Fran's the expert at these, he sent me a couple he built a while back :-) Fran, you could go into business selling these!

[ukejon]

Thanks Doug. All I want is a perfect recording room with cool mics where I can walk in, press one button, and have gorgeously clean and dynamic recordings. Is that really too much to ask for?

[Gazzamundo]

Just thought I'd give you a little update. Gave in to temptation and bought and Audient MiCO http://www.audient.eu/products/mico-...e-preamplifier - haven't plugged it in yet, so no idea what it's like! Hoping to do some recording this coming week, and when I do, I'll post it to Soundcloud or Youtube and you can have a listen and let me know what you think (I've not posted any of my stuff on the AGF yet).

[sdelsolray]

Originally Posted by Gazzamundo

Just thought I'd give you a little update. Gave in to temptation and bought and Audient MiCO http://www.audient.eu/products/mico-...e-preamplifier - haven't plugged it in yet, so no idea what it's like! Hoping to do some recording this coming week, and when I do, I'll post it to Soundcloud or Youtube and you can have a listen and let me know what you think (I've not posted any of my stuff on the AGF yet).

You have two connecting paths between your new Audient and your Alexis - (i) analog or (ii) SPDIF. Connecting via analog will use the Alexis analog preamp circuitry and will use the Alexis AD converters. Connecting via SPDIF will use only the Audient's preamps and its AD converters, leaving the Alexis to function merely as a SPDIF to Firewire protocol converter.

[Rick Shepherd]

Gazzamundo,

Please let us know and post your results! I hope you notice an improvement in your recorded sound.

I am thinking ahead on your behalf now: If you do not notice an improvement in your recording, you will then have two recording interfaces with preamps and converters, one with firewire connectivity, and one without. The Alesis is more useful as an interface to connect to your computer, which leaves you with a new interface with fewer options than your existing one. This potentially leads you back to where you started, still wondering what you would need to upgrade to get better results, and at what cost.

If you had decided to purchase a strictly mic preamp, like the Grace 101 mentioned earlier, you would then be faced with connecting balanced outputs from the preamp to your unbalanced line level inputs of your existing interface, which may not be the most desireable way to ensure a clean signal path. Perhaps someone more knowledgable about this can chime in here.

If your results are better, then what I have to say here is, perhaps, pointless.

Let us know what the results are.

[sehnsucht77]

Originally Posted by Doug Young

I think this is the most important point. I believe I prefaced my first comments on this by saying the preamp won't matter unless the rest of your chain is good as well.

you can buy expensive pres but if your converters, room, mic and monitors aren't up to snuff, you aren't going to hear anything significant. this concept is the foundation of recording; your resulting signal is only as good as its weakest link.

[RRuskin]

Originally Posted by sdelsolray

You have two connecting paths between your new Audient and your Alexis - (i) analog or (ii) SPDIF. Connecting via analog will use the Alexis analog preamp circuitry and will use the Alexis AD converters. Connecting via SPDIF will use only the Audient's preamps and its AD converters, leaving the Alexis to function merely as a SPDIF to Firewire protocol converter.

More ways out than that: AES/EBU, S/PDIF Coaxial and TOSLINK. Toslink is the simplest interconnect with Alesis products since that is their native protocol.