Why use a tube mic?

[MadHatterTCM]

Martin,
Are you offering Google & wiki as sources of accurate info?
12 years olds are taught to corroborate with three sources & preferably NOT wiki amongst them - which suggests that we all need to be careful with open sources.
Google is ubiquitous but not exhaustive or definitive. Any search engine that is a business and requires a fee for listing is going to be "convenient" not "reliable". It worries me that instead of suggesting one search the net clever manipulation has seen many folk use the business name Google as a verb and advert in one.

1. wiki is usually useful on fairly common knowledge. Especially since most of wiki is actually backed with sources that are listed below the information. Since not all of it has a source, and because it's not the direct source, yeah it's not preferred in school.

2. Google doesn't charge anything for any listings. In fact, before you even list your website, more than likely google has found and added your website automatically if any other website is linked to it..

The only thing Google charges is for the advertised listings on the right side. And since that is the only thing they charge for, for allllll of the services they provide like the #1 search engine which isn't biased and based on a formula of relevance and popularity that no one can figure out, free email, photo management, maps etc... some advertisements on the right side out of the way is a far exchange. Yahoo is actually the one who blends paid listings vs real relevant ones...

Sorrry, I'm a web designer and a Search Engine Optimizer... i had to butt in... continue on about FET vs tube....

 

[MartinKantola]

Wont it depend on the design of the preamp circuit? Clipping can start at virtually no i/p level if it's wired to do so.

Was talking about the circuitry in the microphone itself, not the mike preamp. Not aware of any microphone that clips below 100dB SPL, some can take as much as 140dB or even more.

Martin

 

[_brian_]

Was talking about the circuitry in the microphone itself, not the mike preamp. Not aware of any microphone that clips below 100dB SPL, some can take as much as 140dB or even more.

Martin

I was talking about the mic circuitry as well!! Wouldn't the tube mic have small preamp circuit built in to give out just enough gain for the tube to start working at it's optimum level? I'm not talking about harsh clipping I'm talking about a mild clipping circuit. I know nothing much about mic circuitry, but it is an educated guess.

 

[MartinKantola]

This is an interesting question. Microphones are almost the only audio devices without some form of gain or sensitivity control (except for the odd pad). So, it's a tough job to cope with the full dynamic range of music.

If you sing softly into a tube mike, the tube will receive a low level signal. As the SPL increases, the internal level increases. So does distortion, gradually but not linearily. Usually a lot more as we get really loud compared to average levels. Most manufacturers define the max SPL level when a certain percentage of distortion has been reached, might be close to clipping but not necessarily. This would be the "mild clipping area", a strong feature of tube mikes.

The other interesting fact is that the signal level at the capsule in a typical LDC tube mic is surprisingly high. It is still amplified by the tube, but then brought down again in level again by the transformer. In the end we have an output level from the microphone very close to what's present at the capsule output to begin with. But the output impedance has been greatly reduced, so that we can feed microphone cables without too much signal loss.

Martin

 

[Micter]

I think you need to relax Martin. You're the one who jumped in here correcting people as though you are the ultimate authority. It is fairly common information all over that tubes do indeed supress odd order harmonics and allow second order to be predominant. It's all over the web and books that I have. I can provide you with many links, but I'm sure you can easily find them on your own.

And perhaps I should have said, "a higher costing or better FET" and not "expensive". You seem to feel the need to take over rather than contribute. Keep it up on this site and you'll find yourself ostracized rather quickly.

Tubes add odd numbered harmonics which are musical 1,3,5,7,9,13 are the basic chordal structures. 2,4,6 are less musical (dissonant). I'm not trying to cause an issue here but things are a tad bit backwards in this thread.

carry on!

 

[donkeystyle]

Tubes add odd numbered harmonics which are musical 1,3,5,7,9,13 are the basic chordal structures. 2,4,6 are less musical (dissonant). I'm not trying to cause an issue here but things are a tad bit backwards in this thread.

carry on!

That is exactly opposite of everything I have ever heard.

I hate the blanket statements where people claim that "tubes add even order harmonics" and "Transitors add odd order harmonics." There is a lot more to it than that and most that have replied have oversimplified their answers to the point that they are not true, or at least misleading. Though, MartinKantola does seem like he's on the right track.

Just keep in mind that both tube and solid state devices produce even and odd harmonics.

I also don't beleive that putting a tube pre behind an FET mic will give you the sound of a tube mic. I also don't believe that putting a transformer based pre behind an FET mic is the same thing as using a transformer mic.

 

[PhilGood]

Tubes add odd numbered harmonics which are musical 1,3,5,7,9,13 are the basic chordal structures. 2,4,6 are less musical (dissonant). I'm not trying to cause an issue here but things are a tad bit backwards in this thread.

carry on!

Read here under Harmonic and Content distortion:

http://en.wikipedia.org/wiki/Tube_sound

 

[PhilGood]

Phil, you had many excellent points I do agree 100% with, but only chose to comment a couple of things.

As an example I'm with you that tubes usually "behave better" when driven into clipping, any guitar player knows that. But in my experience, microphones are not normally operated at such high SPL's, so I can't agree with your general claim that:



Looking at it the other way, I don't think it's the presence of even order harmonics that make tube microphones sound great.

Truly sorry if you felt my comments to be too aggressive... Will try to be more polite next time.

Martin

Excellent points Martin! Glad you are here and contributing. We will look forward to your insights.

I agree that the sound of a tube mic is not great because of the distortions or harmonics that happen. I think that it is the cleanness of sound and hi-fi characteristics before distortion that a tube circuit provides that is what makes a good tube mic a gem. It has been my experience that the performance really has to do with how well the circuit is designed and the quality of it's components, whether tube or solid state.

Coloration (as the OP described) is generally a result of the transformer core material and design and even diaphragm material and thickness.

 

[PhilGood]

Here's something for all to consider.

Why are tube mics preferred? One reason is that the top 5-6 microphones considered to be the greatest mics of all time happen to be tube microphones.

The U47
AKG C12
Telefunken Ela M 250-251
Neumann M49
Neumann U67
Sony C800G

Yes, you can argue about if these belong as the top ones or not, but that's really not the point!

The point is, just because the top mics in the world are tube, does that mean all tube mics are good? Obviously not!

We have some fine examples of bad tube mics all around us. Why do you think so many people around the world are modifying their Apex 460's? Because it's a great mic? It's a fairly bad mic that can be made better by improving the design.

Don't think for one second that just because it has a tube that it's going to sound like gold. There's a lot more to it than that!

Want a good mic? Buy a good mic!

 

[_brian_]

Interesting!! The Apex 460 seems to be relatively cheap to buy, what kind of results are we talking about getting after modding one? Is it inexpensive & fairly easy to do? I was going to buy a cad m179 mic sometime, but am open to other suggestions.

 

[MCI2424]

Here's something for all to consider.

Why are tube mics preferred? One reason is that the top 5-6 microphones considered to be the greatest mics of all time happen to be tube microphones.

The U47
AKG C12
Telefunken Ela M 250-251
Neumann M49
Neumann U67
Sony C800G

Yes, you can argue about if these belong as the top ones or not, but that's really not the point!

The point is, just because the top mics in the world are tube, does that mean all tube mics are good? Obviously not!

We have some fine examples of bad tube mics all around us. Why do you think so many people around the world are modifying their Apex 460's? Because it's a great mic? It's a fairly bad mic that can be made better by improving the design.

Don't think for one second that just because it has a tube that it's going to sound like gold. There's a lot more to it than that!

Want a good mic? Buy a good mic!

Party Pooper.

 

[dgatwood]

That is exactly opposite of everything I have ever heard.

That's probably because musicians and electronics people disagree about what the meaning of "first harmonic" is. Musicians refer to the fundamental separately and the octave above it as the first harmonic. Electronics people refer to the fundamental as the first harmonic.

So musicians would say that the even order harmonics are the out-of-tune ones: octave and a fifth (okay), two plus a third (bad), two plus a minor seventh (horrible), etc. Electronics folks would say that the even order harmonics are the in-tune ones: the octave, the second octave, two octaves plus a fifth, three octaves, etc.

 

[bobbarker12]

why??? because you CAN!!!

 

[PhilGood]

Interesting!! The Apex 460 seems to be relatively cheap to buy, what kind of results are we talking about getting after modding one? Is it inexpensive & fairly easy to do? I was going to buy a cad m179 mic sometime, but am open to other suggestions.

Just do a search for Apex 460 mod here and elsewhere. Lots of reading and learning, but well worth it if even just for the education.

 

[NL5]

This is an interesting question.

Hey - sorry to thread jack, but what ever happened with the NU-47?

 

[rayc]

Madhatter,
Visualise me eating humble pie! I was sure (probably looked it up on the net???) that google had a fee but am obviously wrong. What criteria, apart from Chinese Govt approval, do they use? Dogpile used to be pretty good but it changed a lot. I'll just hoover the carpet before going for a coke.
Wiki is notoroius downunder due to the manipulation our last prime minister's office did to certain entires that reflected poorly on his government. The changes were in relation to the "Children Overboard" scandal. The staffers applied a very Ministry of Truth sense to their revisionist recreation of history. Foryunately they were bsuted after a while because lots of people were researching the topic with an election on the horizon.