Tube mic distortion

Downside Studio

Downside Studio

New member
While reading the other thread about the listing of all cheaper tubemics I thought of the following question. (btw, that thread ain't nowhere near a tubemic thread anymore...)

I have two GrooveTubes MD1. These mics are excellent...very clear response, very nice coloring sound. But there are terrible for loud vocals. If a male or female sings into them they will sonicly distort beyond the point of being usefull. I don't get it....GT claims that Van Halen among others use these as there main vocal mics....

Now I primarily use these mics as overheads or acoustic guitar mics, and I am more than pleased with the result, but I would also like them to be used on vocals...I've worked for a couple of weeks with the AKG solidtube, and though it does sound clean and warm, I'm having second thoughts about this mic. I'm not sure why, but for i just don't like this mic.

Anyway, back to the subject...a while ago I was following a thread at the digidesign forum, in which a lot of people claimed that the neumann M147 and M149 had the same problem. They sonicly distort when a loud male vocals uses them......

Btw, the GrooveTube MD1 is one of the first models they made, way before they were taking over by....ales....ales.....ales.......stutter..stutter....alesi......oh well, some cheap brand.
 
Hey Downside,

I have a chance to pick up a used MD2 for about 350 bones.

Do you think that's a good deal?

I've heard Matthew Sweat used to use them for guitar and vocal on just about all of his older material.

As far as the whole distortion thing goes, I think that's kind of the idea behind it all, isn't it? :D Anyway, for louder vocals I think you'd really like an SM7 . . . do you have any of those lying around anywhere?
 
Hey Chess,

well go and listen for yourself....i've never worked with the MD2.

I bought the md1 without listening, and only because I knew the early groovetube models were good according to people. And I must say that I'm very pleased with the mic. Within a month I found a second and bought that one too. Always have stereopairs!!:)

but like I mentioned, the mic rocks on some parts, while being totally useless at other parts. Taste?:confused:

Be shure to have the powersupply with it..otherwise it will be useless. I'm lucky enough to have bought the fourpart powersupply with one of the mics, and the single one with the other...so I have two mics, but 5(!) powersupplies!
 
Well obviously, a mic's overload point lies in the Max. SPL spec.; assuming it's not the preamp input overloading.

But if you're talking about THD (which I'm pretty sure is what chessrock's reply is refering to), that's a different issue, though it is directly related to SPL.
 
In the case of the M-147 and M-149 their output can be measured in "horsepower"... it's much more likely that something else down the signal chain is craping out.

The "scientists" at Neumann have endeavored to put out a product with the absolute best 'specifications' possible... in order to drive the 'noise spec' into the dirt, they put a very high gain amplifier into the microphone... which many mic pre's can't handle [unless you add an "in-line pad" to the signal prior to the mic pre].
 
I've tried a neumann m147 and I agree on what you say. The max SPL is indeed rated to 117 db's if I'm not mistaken, a little bit low. I did experienced this with a singer, she was very dynamic. Even if she was 8-10 in away from the mic (with pop filter obviously), she could make the mic distort if she wanted very easily.
 
MrGrooves, I suppose you didn't read Fletcher's post, did you?

I have an M149 and indeed you can connect it almost to the line in of the board. The mic itself doesn't distort under normal conditions, even a metal singer can't make it distort, unless he "swallows' it.
 
I'm sure there's nothing in the path going into red, or being overloaded. The gain I have to use is pretty much normal. It is really coming from the mic(s).
 
Well lets first determine if you're talking outright "big ball of distortion" on peaks or overall, from something overloading or VERY obvious "soft fuzziness breakup" on peaks or overall, from THD.
 
The latter, on the loud passages you can hear an amount of 'subtile' distortion being added. Same when you give a tube preamp to much gain. It's like the saturation is becoming hearable over the top. Only is such a way that it actually ain't subtile anymore, and is just plain useless.

Let me put it this way:

My mother or the neighbour next door wouldn't notice it at all.
Most of the people on this bs would.
 
Well, considering you say the amount of gain needed seems normal and what you just described above, I think you may be right about it being the mics! I mean, even 1% THD is rather significantly noticeable when mostly second and even order harmonics... And obviously, the higher the SPL, the higher the THD.

But still, I'm only taking a big stab in the dark.

By the way, there's quite a difference between the M147 and M149. The M147 has a Max. Output Level of +8dBu (1.95Vrms) while the M149 has a Max. Output Level of +18dBu (6.16Vrms). Obviously, Max. Output Level would be at Max. SPL.

But out of curiosity, what is the preamp and recorder?
 
I have three different preamps available.

1. TLAudio 5001 tube.
2. Soundtracs Solitaire preamps
3. Custombuild preamps for live recordings.

recorders are either Tascam DA88/38 or Protools (888)
I should mention the distortion is noticable both pre and post tape, and it also noticable on my previous desk, a Tascam TMD8000.

It really seems to be the mic, though today it struck me once again how clean and detailed it sounds when used as overhead for drums. But that's a complete other source when it comes to frequencies and distance to mic so.....
 
That's indeed one of the things that i'm gonna check, but I think it is not the problem.

Both mics behave the same way, but are not from the same year, of same previous owner.......
 
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