Se electronics gemini ii loud hissing noise

[alexhedleymusic]

Hi!

I know all mics hiss a bit but this is so much louder than my sm57 and at the moment it just seems to be ruining all of my recordings a bit. iv'e had the mic for about 7 or 8 years and iv'e never changed the tubes so this could well be the problem. i seem to recall it allways being quite hissy though even when it was new. But yeah compared to the 57 its just insane how much more hiss there is to it. iv'e used the pad on it and that doesnt help either. is this a thing with tube mics? not sure... any help would be great

Thanks!!

[Drew Stephenson]

Tubes can go over time, but also connectors oxidise. Have you tried taking the tube out and reseating it?

(Edited for clarity!)

[Hugh Robjohns]

Comparing active capacitor mics with passive dynamics is always a little misleading because the dynamic has only the thermal noise of the coil impedance to generate hiss, and the high mass of its diaphragm makes it relatively unresponsive to ambient acoustic noise.

In contrast, a capacitor mic is inherently more sensitive to acoustic ambient noise and the impedance converter electronics will also generate noise — especially in a valve mic which is typically 6-8dB noisier than a solid state mic.

However, the Gemini has a sensitivity of 40mV/Pa, compared to the SM57's 1.5mV/Pa, so the output level will obviously be about 28dB louder for the same source level and the same position. You would therefore need 28dB less preamp gain to make a comparison valid and it's not entirely clear from your post whether you have taken that into account, or are just swapping mics on the end of the cable.

But, if the Gemini is obviously noisy after the appropriate gain compensation then the mic is almost certainly faulty. I'd be slightly surprised if swapping valves cured it, but it's a reasonably easy and affordable thing to try.

[alexhedleymusic]

Comparing active capacitor mics with passive dynamics is always a little misleading because the dynamic has only the thermal noise of the coil impedance to generate hiss, and the high mass of its diaphragm makes it relatively unresponsive to ambient acoustic noise.

In contrast, a capacitor mic is inherently more sensitive to acoustic ambient noise and the impedance converter electronics will also generate noise — especially in a valve mic which is typically 6-8dB noisier than a solid state mic.

However, the Gemini has a sensitivity of 40mV/Pa, compared to the SM57's 1.5mV/Pa, so the output level will obviously be about 28dB louder for the same source level and the same position. You would therefore need 28dB less preamp gain to make a comparison valid and it's not entirely clear from your post whether you have taken that into account, or are just swapping mics on the end of the cable.

But, if the Gemini is obviously noisy after the appropriate gain compensation then the mic is almost certainly faulty. I'd be slightly surprised if swapping valves cured it, but it's a reasonably easy and affordable thing to try.

hi hugh,

yeah apologies i forgot to mention. this is with me changing the gains to match the recording levels of the same sound source and its definitely a hell of a lot louder than the 57 still. maybe il contact se electronics about this in that case and see what there take is on it. thanks!

[Hugh Robjohns]

Well, if the gains are matched and the mics are the same distance from the same source I would expect the Gemini to be a little noisier than the SM57... but certainly not unusably so.

[alexhedleymusic]

Well, if the gains are matched and the mics are the same distance from the same source I would expect the Gemini to be a little noisier than the SM57... but certainly not unusably so.

this is a little bit different to the original question but iv'e just been trying different things and while the gemini is a lot louder with hiss the 57 is also quite loud. When your recording is eliminating hiss something that has to be done or should it not be there in the first place. its really annoying at the moment and i dont feel like i can start recording til i get rid of the hiss. I used a noise reduction plugin by klevgrand and it does get rid of this hiss but only by rolling of the top end which i dont want either. when i put the top end back in the hiss is the same. im using a focusrite 2i2 interface.... and yeah id just be really grateful of any reccomendations on this as its just a neverending thing at the moment and cant figure it out.
thanks for your help!

[alexhedleymusic]

Well, if the gains are matched and the mics are the same distance from the same source I would expect the Gemini to be a little noisier than the SM57... but certainly not unusably so.

this is a little bit different to the original question but iv'e just been trying different things and while the gemini is a lot louder with hiss the 57 is also quite loud. When your recording is eliminating hiss something that has to be done or should it not be there in the first place. its really annoying at the moment and i dont feel like i can start recording til i get rid of the hiss. I used a noise reduction plugin by klevgrand and it does get rid of this hiss but only by rolling of the top end which i dont want either. when i put the top end back in the hiss is the same. im using a focusrite 2i2 interface.... and yeah id just be really grateful of any reccomendations on this as its just a neverending thing at the moment and cant figure it out.
thanks for your help!

also i just tried the same setup through a brand new behringer interface and the same hiss was there so i dont think its the interface....

[Hugh Robjohns]

...while the gemini is a lot louder with hiss the 57 is also quite loud.

Then I would suggest investigating three possibilities:

1. Whether the 'hiss' is actually ambient acoustic noise rather than electronic. It often is, and our brains are very good at ignoring it in real life, but notice it when a mic picks it up.

The best way of checking that is to replace the mic temporarily with a 'termination plug' comprising a male XLR plug with a 150 Ohm metal oxide (or metal film) resistor wired between pins 2 and 3. What's the noise level like with that?

2. Whether your gain structure is sub optimal?

3. Whether your preamp/interface is not quiet enough for your application?

The preamps in the 2i2 are actually pretty good. The spec quotes -128dB A weighted which isn't bad at all. Better than a Neve 1073...