Some Mixing Tips

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It is SO worth reading it. But if you want to save some time, you can go to one of the last pages where a wonderful individual has posted the whole thread with the BS edited out as a Word file. It's imperative to download and print that. And read it.

Harvey,
I posted a question for you on the big thread regarding mic and preamp impedance. I'd be very happy if you'd take the time to look into that one.

Cheers
/Henrik
 
Henrik said:
It is SO worth reading it. But if you want to save some time, you can go to one of the last pages where a wonderful individual has posted the whole thread with the BS edited out as a Word file. It's imperative to download and print that. And read it.

Harvey,
I posted a question for you on the big thread regarding mic and preamp impedance. I'd be very happy if you'd take the time to look into that one.

Cheers
/Henrik
Henrik,
Here's what you asked and I'll try to answer it here:
Got a question for you here Harvey about impedance (hope this hasn't been covered):

I understand the impedance of a specific mic can make it more or less suitable to couple it with a specific preamp. I wonder if you could elaborate a little around this (why isn't there a standard impedance? What are the tradeoffs with high/low impedances in mics and pre's? etc), or at least list the do's and dont's when it comes to matching mic and preamp impedances.

I hope this is possible without having to start the electronics class from the beginning, hehe. I'm not a very techincal person you see.

Thanks
/Henrik
This is really a better question for Dan Kennedy, but in general, low impedance balanced circuits allow long cable runs and relative freedom from induced noise. There is nothing inherantly bad about using hi-impedance mics with short cables, but in typical studios, it's too easy to need loner runs for most situations. The way a microphone is designed determines it's output impedance and the load it wants to see from a preamp.

Ribbon mics are like a dynamic, but where a dynamic mic uses a lot of wire in the coil, the ribbon itself is the "coil of wire" function, and it's very low impedance - almost a dead short. A ribbon requires a transformer to incease the impedance and boost the signal, but the noise is boosted along with the very weak signal, so the impedance is kept very low, usually 50 to 250 ohms maximum.

Most dynamic mics can run 200 to 600 ohms with good output and low noise so those require a different kind of preamp load.

Condenser capsules are in the gigohm range and they have a problem in reverse - getting the impedance lower, which requires an impedance converting stage - either an FET or a tube, which then presents it's own set of output requirements to the preamp.

In general, most mics like to see a slightly higher impedance so that the mic doesn't get loaded too heavily by the preamp. The preamp usually runs about 5:1 or 10:1 higher that the mic. For a 200 ohm mic, that works out to be around a 1 to 2k preamp impedance.
 
Here's a thread I found over in the rack that pretty well answers your question:

https://homerecording.com/bbs//showthread.php?s=&postid=369406#post369406

and here's Dan Kennedy's post on load impedance:

Load impedance, eh?

Well, in general, a dynamic type mic, including ribbons is sensitive to the load, because it is after all a generator.

When operated into a light load the higher frequencies will typically be extended. With a heavier load i.e. lower input impedance, the high end will drop. At some point the lower impedance will also interact with the inductance of the mics output (be it a matching transformer or the coil itself) and this will cause the low end to start rolling off as well, giving a honky midrangy tone.

With some condensors, those with output transformers and wimpy amplifiers, like KM-84's, original U87's you'll get fairly similar responses plus that always desirable distortion boost when that poor little FET is driving a low-Z input.

Others, like most Schoeps, about half of the Chinese knock-offs and most of the new Neumanns don't really care. The other half of the knock-offs will behave like the KM-84, but worse because they have truly crappy output transformers.

Most mics are designed for load impedances of 1K to 3K for "flat" response.

What's it mean for you? Try it, use it like an equalizer, be sure you aren't causing the mic to puke with too low an impedance and have fun. You won't cause any damage to the mics, it just may not sound good. It might be louder, but be careful with that, listen to the characteristics, not volume.
 
Great, thanks Harvey!

I checked out the SM57 specs, which state that it is 150 ohms (310 actual). So if I understand you and Dan Kennedy correctly, you would want a mic preamp with 1.5 to 3Kohms load in order to get all the high and low frequencies from it?

Thanks again
/Henrik
 
I just want to mention that after reading the "big thread" a little while ago I decided to try recording my acoustic (Martin classical) guitar with two Marshall 603 mics in an "x/y" configuration. I'm working on something like now and it's turning out to be a great idea for me. (So I did come away with very specific "advice" after taking the time to read the whole thing.)
 
WAY TO GO HARVEY !

This is your greatest post ever.

On behalf of the BBS thanks again for your time, patience, & endless
dedication to our beloved art form, MUSIC.


Sean
 
darrin_h2000 said:
I can see the meeting with Pink Floyd now. First you would offer them cigars, then tell them how they are going to make it and everyone will love them, and then ask which one is Pink.
Deja Vu
 
Thanks for all the great info Harvey!

While reading this thread,I stumbled across the "Big" mic thread and stayed up most of the night reading it.Tonight,I had a session with a singer/songwriter Martin D-35 playin good friend of mine and your tips on mic placement resulted in a vast improvement in the sound we have been getting on his tunes.

YOU ROCK!
 
While looking for something else, I stumbled across this thread from a few years ago. I thought it might be of interest to some of you.
 
tdukex said:
This is still a great thread, Harvey. It should come back to the top at least once per year.
I think these types of threads would certainly be a lot more productive, a better use of my time, and way more helpful to the group, then all the time I spend here lately, mostly defending myself and answering nit-picking posts.
 
Harvey-

Threads like these are why 95% of the people on this BBS have a ton of respect for you.

Thanks for sharing your knowledge.

BTW-the other 5% can kiss my (and your) ass.
 
H2oskiphil said:
Harvey-

Threads like these are why 95% of the people on this BBS have a ton of respect for you.

Thanks for sharing your knowledge.

BTW-the other 5% can kiss my (and your) ass.
I fear the days of threads like these are long gone.
 
still checking things out.

I'm in the experimentle stages with mic.s verses what I can afford. but I read somewhere that yeah, you want to use the best mics you can get but if your other equipment isnt any good, then your mic.s will do a good job picking up bad sound.
 
Harvey Gerst said:
I fear the days of threads like these are long gone.

Absolutely! There was a time in the not so distant past when this site was about sharing each others experiences and expertise. It's definitely not at the level of fun and interest it was in prior years.
 
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Re: still checking things out.

kevin45 said:
I'm in the experimentle stages with mic.s verses what I can afford. but I read somewhere that yeah, you want to use the best mics you can get but if your other equipment isnt any good, then your mic.s will do a good job picking up bad sound.
Each link in the recording chain makes its own contribution. Bad, good, and best are terms that can be used to describe sounds, but often simply "right" or "wrong" may be better terms.

Because a particular mic may not work right for a specific song, it doesn't make it bad, just wrong for that song. It may work great or even best somewhere else. And all too often, mic placement changes can make major changes to the sound.

More often then not, I'll find myself thinking, "Wow, that sucks, but it's kinda cool; I gotta remember that." Then I'll use that sound in another song.
 
Harvey-

How do you document things like mic placement, etc.? I document the beejesus out of my sessions, but I feel kinda stupid standing in front of the talent writing things down in a spiral-bound notebook...
 
H2oskiphil said:
Harvey-

How do you document things like mic placement, etc.? I document the beejesus out of my sessions, but I feel kinda stupid standing in front of the talent writing things down in a spiral-bound notebook...
Most of the time, I don't document stuff; I just try to remember it. One important trick I use is to NOT run EQ on anything that may require punch-ins later, like vocals, lead guitars, etc. That saves a lot of time when the singer or guitarist decides that he/she didn't like the whole take two weeks later.

While we're doing scratch parts during the basic tracking, I'm also thinking ahead about what mics I may want to try on the vocalist, based on what I'm hearing on the scratch mic. Sometimes, the scratch mic (either the Beyer Soundstar MKII or the Shure SM-7) winds up being the best mic for the job.

But, from that starting point, I'll figure out whether I want more top end (a condenser mic), a more mellow sound (ribbon), or whatever. I'll figure out where to position the pop filter to give me the right amount of proximity effect, and the right amount of dynamic range changes (if the singer moves around - something that's never been covered in any thread here, but is very important).

But over the years, I've learned the characteristics of the different mics I own for recording sources miked at different distances. If it's a very soft singer, I might use a normally bright condenser in very close for extended proximity effect (about an inch away from the mic), as opposed to a ribbon mic a foot away (same amount of proximity effect, but less output and less top end).

And this brings up the subject of "radio friendly" vocals. What's that mean? It means the vocal sound is unique, and easily identifiable on the radio, without the need for an announcer to tell you the name of the artist. When you can name the artist on a new song, that means they have a "radio friendly" voice or trademark sound.
 
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