mic hiss

[Shadow_7]

It's all free, so you only have to register once - then it's as easy as this forum.

Yes, but if you logout here, you can still READ the forum. You just can't post. There you have to register and login to see ANYTHING. Just a wee bit weary of sites that require a birthdate or SSN or email just to look at what they MIGHT have. Oracle used to require an SSN just to download the documentation on how to use their product. And Progressive also required an SSN for a quote. (your *cough* protected TAX ID number). Just lame. Plus a lot of those sites have other registration requirements not listed until you get past the initial give us your private email thing. It's just a bit overboard to look at the specs that they MIGHT have for a mic that you MIGHT be interested in.

Step 1 - register and give up your email
Step 2 - tell us everything about your first born. Her bra size, her address, her last 3 tax returns...
Step 3 - we're almost ready learn about baking cookies. All we need now is your credit card numbers.
Step 4 - enjoy our closet. It's empty right now, but we fully intent to put something in it someday.

 

[timtimtim]

It's all free, so you only have to register once - then it's as easy as this forum.

I'm registered and its a very useful site, though there's sometimes bits missing from the specs.

A general question about condensor mics (I'm sorry to be always asking these general questions but I want to get a feel for the whole thing):
are electret mics (generaly speaking) as good as SDC phantom powered mics, or not? I mean in terms of quality; hiss, response, lack of coloration, accuracy

 

[mshilarious]

A general question about condensor mics (I'm sorry to be always asking these general questions but I want to get a feel for the whole thing):
are electret mics (generaly speaking) as good as SDC phantom powered mics, or not? I mean in terms of quality; hiss, response, lack of coloration, accuracy

It's difficult to make general statements about electret vs. externally biased (for purposes of this post, "EB") condensers (although some generalizations can be made about DC bias vs. RF condensers, which Mr. Willett will be happy to describe ).

The easiest generalization is that the average electret is smaller than the average EB; that is, there aren't a lot of large-diaphragm electrets. The AT3035/AT2035 and AT3060 are the only ones I know of off the top of my head. The Shure KSM32 and KSM141 are a little more than 1/2", the SM81 is right at 1/2". Most really small diaphragm mics (1/4" or less) are electrets, which includes the DPAs.

So perhaps on the basis of electrets tending to be smaller, we could say they are noisier but more accurate (small = better transient and thus high frequency response). But there is no physical barrier to making a 1/4" EB that achieves the same goals. And again, note that the electret AT3035 achieved a better noise spec (12dBA) than the EB Shure KSM27 (14dBA), although Shure's newer EB SM27 is lower still.

The bottom line is it's really down to the individual microphone, application, and preference of the engineer--Shure KSM141, AT4051, or Beyer MC930? DPA4006 or Schoeps MK2? Or go crazy and get the RF Senn MKHs?

 

[timtimtim]

Thanks for that. I'll have to look at lots of mic specs and think about it.
I'm trying to be really "reductionist" about this and not let subjective judgements like "lovely warm sound" or "sharp" or "full sound" influence me because peoples ideas differ, and because I want to use this mic for various different purposes, not just for music. I know some people will say you need different mics for different uses, but I suppose I've got this purist feeling that I want the mic to hear the sound, whatever it is, exactly as my ear does. Any boosting of bass or HF can easily be done later if required.
I've got this electret mic EM-103L already and it sounds fine to my ears (I can't find a figure for it's self-noise, and it isn't listed at microphone-data.com) but I can't help wondering whether a more expensive mic would amaze me with it's clarity and quietness? But I havn't got a lot of money to throw around so I've got to think carefully before buying anything.

 

[mshilarious]

Based on the info you dug up for that mic, it has stated 29dB self-noise, but we don't know if that is unweighted, CCIR, or A-weighted. It likely isn't the latter, so we can place its self-noise somewhere between 18dBA and 25dBA. Most people find 25dBA objectionable on quiet sources, so maybe it is quieter than that.

The best compromise between noise and accuracy is probably a 1/2" microphone; you might look for an AT3031 (cardioid) or AT3032 (omni) on the used market (they are discontinued).

 

[timtimtim]

Based on the info you dug up for that mic, it has stated 29dB self-noise, but we don't know if that is unweighted, CCIR, or A-weighted. It likely isn't the latter, so we can place its self-noise somewhere between 18dBA and 25dBA. Most people find 25dBA objectionable on quiet sources, so maybe it is quieter than that.

The best compromise between noise and accuracy is probably a 1/2" microphone; you might look for an AT3031 (cardioid) or AT3032 (omni) on the used market (they are discontinued).

That's useful - now I have some idea how my mic compares to other mics.

I looked up those two at microphone-data.com and they look nice. If I buy one I'll get at least 2dB better hiss, maybe 9dB?

How does phantom power happen? Do I need a 12v and a 48v battery?

If I buy it 2nd hand how do I know its in good condition? Would it need servicing?

The spec doesn't state 1/2" diaphragm, but at .82" dia body, I suppose it must be about that?

So I'm sorely tempted. D'you think I'll notice the difference in quality between the EM-103L and the AT 3032?

 

[Shadow_7]

The AT4022 is the next generation of the AT3032. Some argue that they're the same mic.

Mics generally hold their value. Past the initial 1/2MSRP once it's not new. SDC's which probably don't see much action as vocal mics probably don't need servicing. Not to imply still operating at factory specifications. Just make sure that there's no obvious physical damage and that it still works. Before forking over some cash if you're buying used. A field recorder or a usb interface and a laptop can do that for you on location without too much hassle. Not that you can tell how well it's working, but anything obvious should be obvious.

 

[timtimtim]

The AT4022 is the next generation of the AT3032. Some argue that they're the same mic.

But the 4022 is 3dB quieter!

 

[Shadow_7]

The 3032 is popular in the nature recording circles because it's noise specs are over stated. It actually performs better than the specs. And for a nice price point too. The 4022 adjusts the specs and ups the price. Or so they say. And the motivator behind the now discontinued 3032.

 

[timtimtim]

The 3032 is popular in the nature recording circles because it's noise specs are over stated. It actually performs better than the specs. And for a nice price point too. The 4022 adjusts the specs and ups the price. Or so they say. And the motivator behind the now discontinued 3032.

Ah. Maybe I'll go for the 3032 then. Have you compared both?

 

[Shadow_7]

Ah. Maybe I'll go for the 3032 then. Have you compared both?

Not yet. Although my curiosity on the 4022's has been perked. They meet the specs that I desire in almost all aspects. Except for two. And one might just be playing it safe, and the other of little consequence. AFAIK, all AT mics have that 110F no direct sunlight, avoid humidity disclaimer. For my region, that's more of an average day, than a max day. And the 4022's don't seem to come as stereo pairs. Otherwise getting those or spending many times their price point for basically equal (in specs) mics has it's charm.

 

[timtimtim]

I'd be very interested to know if the noise of those 2 mics is the same. Does anyone else out there know if AT3032 is as quiet as AT4022?
I havn't looked at any 2nd hand prices for either yet, but I'd rather get a new one if I can afford it (which I probably can't).
Luckily in my part of the planet that 110F limit wont affect me much.
As for stereo pairs: I looked at Rode Stereo Video Mic, but its response is not quite so flat (if those response charts are to be believed)

 

[Shadow_7]

You can EQ in post to flatten that curve. Not ideal, but an option. I'd rather just spend a few bucks and not have the hassle myself. Plus there's other gains past a certain level.

One should note that 3dB isn't really that much in terms of specs. It's a bit and noticeable in some situations. I used to do a 3dB bump in EQ, now more towards 1dB, if I even bother with that edit.

at3032 - 16dB noise / 78dB S/N
at4022 - 13dB noise / 81dB S/N

Not really much different even if the specs were to be trusted. As opposed to my current mics.

STO-2 - 28dB noise / 66 S/N
(based on rumored specs and that calculator thing)

Perfectly fine mics even for event stuff. As long as you have a loud source and/or proximity. 40+ brass players / rock concert / ..... Basically if you're just going for a stereo capture and have proximity, it doesn't matter all that much. If you don't have proximity (top of a stadium), or a soft source (butterflies on a summers day), or are mixing 2,000 tracks for some reason. Then it matters a bit more. As long as you're in proximity of 80dB S/N, you're pretty much set. Unless you want to record an unamped flute soloist from the back of an auditorium for some reason.

 

[timtimtim]

28dB certainly is noisy.
The reason I'm so obsessive about hiss is I will be using this mic for filming amongst other things, and I'd like to be able to film people whispering very quietly to each other (not necessarily a **** film ) without obvious background hiss.

Another thing I'm concerned about is phantom power. Out in the field do they use a 48v battery, or an inverter to step up 12v to 48v, or do they just use 12v? Which leads me to my next question: are the mic specs, specificaly signal/noise ratio, altered by using only 12v for phantom power?

That's interesting - I put a certain word in there describing certain sorts of films involving men and women, and it has automaticaly removed it.

 

[Shadow_7]

Some phantom powered mics (SM81) don't need full 48v phantom power. So 12V can power those type of mics and save a lot of battery life on your recording gear(1/4th the volts). If you don't need the benefit of battery life, you could probably safely ignore the 12v option all together. Many mics that offer the 48v, 12v, and AA (or 9V) power options still tend to do noticeably better at 48v. So if you don't have the "need", it's probably best to avoid it for now. It's just an option, one of many.

Bear in mind you can do a voice over in post for whispers and things. Given that sound is directional and even with a good mic on location the directionality of the content could negate the ability to capture it on location. You might be surprised at just how often it's done that way. How do you think they derive the french, russian, and other alternate sound tracks? And you don't really need a lot of pro gear to do that. Just the time and abilities in post to edit it in seamlessly (or close to it).

**** that's nothing. You should see what it does to certain website URLs.

 

[mshilarious]

28dB certainly is noisy.
Another thing I'm concerned about is phantom power. Out in the field do they use a 48v battery, or an inverter to step up 12v to 48v, or do they just use 12v? Which leads me to my next question: are the mic specs, specificaly signal/noise ratio, altered by using only 12v for phantom power?

If a mic is spec'ed at 12V to 48V (or wider), it should perform to specification at those voltages, or the drop in performance should be specified. Electret mics do not need a high polarization voltage for their capsules, and really only need 12V for their amplifiers (often higher voltages are simply regulated down to 12V or whatever).

On the other hand, there are externally biased condensers that do require a high polarization voltage for their capsules, but use an internal step-up circuit to generate it. These can also run at full spec at their stated phantom supply range.

It is true that some mics that can run off of internal battery power will have better dynamic range when run off of phantom power.

 

[timtimtim]

Some phantom powered mics (SM81) don't need full 48v phantom power. So 12V can power those type of mics and save a lot of battery life on your recording gear(1/4th the volts). If you don't need the benefit of battery life, you could probably safely ignore the 12v option all together. Many mics that offer the 48v, 12v, and AA (or 9V) power options still tend to do noticeably better at 48v. So if you don't have the "need", it's probably best to avoid it for now. It's just an option, one of many.

Bear in mind you can do a voice over in post for whispers and things. Given that sound is directional and even with a good mic on location the directionality of the content could negate the ability to capture it on location. You might be surprised at just how often it's done that way. How do you think they derive the french, russian, and other alternate sound tracks? And you don't really need a lot of pro gear to do that. Just the time and abilities in post to edit it in seamlessly (or close to it).

**** that's nothing. You should see what it does to certain website URLs.

I'm not so worried about battery life, just the inconvenience of having power supplies hanging around.

Yeah I know you can do dubbing etc, but I've got a thing about naturalness, which is why I'd like to use an omni mic for everything, and if there's background noise, well that's fine, its natural (as long as it isn't contradicting the plot in some way, for instance if its supposed to be on a desert island and you can hear cars going by).

 

[timtimtim]

If a mic is spec'ed at 12V to 48V (or wider), it should perform to specification at those voltages, or the drop in performance should be specified. Electret mics do not need a high polarization voltage for their capsules, and really only need 12V for their amplifiers (often higher voltages are simply regulated down to 12V or whatever).

On the other hand, there are externally biased condensers that do require a high polarization voltage for their capsules, but use an internal step-up circuit to generate it. These can also run at full spec at their stated phantom supply range.

It is true that some mics that can run off of internal battery power will have better dynamic range when run off of phantom power.

I misinterpreted the spec, I thought it meant you need 12v and 48v.

I'm thinking specificaly of AD 3032 and AD 4022. When you say better dynamic range do you mean it will give a greater undistorted output at 48v, but the self-noise will be the same as at 12v?

Are 3032 and 4022 electrets or do they step-up 12v to 48v?

The 4022 is 48v only. Does it take an internal battery or does it need external power?

 

[mshilarious]

I misinterpreted the spec, I thought it meant you need 12v and 48v.

I'm thinking specificaly of AD 3032 and AD 4022. When you say better dynamic range do you mean it will give a greater undistorted output at 48v, but the self-noise will be the same as at 12v?

No, unless specified otherwise, I would expect all specs from a reputable manufacturer to be the same across the specified voltage range.

Are 3032 and 4022 electrets or do they step-up 12v to 48v?

They are both electret. I don't know why the 4022 was not spec'ed lower.

The 4022 is 48v only. Does it take an internal battery or does it need external power?

Very few pro mics run on internal battery (AKG C1000S, Shure SM94 are a couple, Rode has one, and AT has some semi-pro mics that do), so unless they stated that, they all need phantom power.

 

[Shadow_7]

When you say better dynamic range do you mean it will give a greater undistorted output at 48v, but the self-noise will be the same as at 12v?

Generally (my interpretation) with the greater power, when it picks up a weak signal (soft noise) it sends something down the chain. As opposed to sending nothing (dynamic range). Not that any of it matters if you don't have the rest of the chain that is sensitive to the full range (relatively).

Some mics run on 48v only, some on 48v OR (but not and) 12v, some on 48v or internal batteries (phantom defaults when both are used for most), some on any one of the three (but only one). Most mics need some form of powering to function at all. Dynamic mics and Ribbon mics being two notable exceptions.

But ribbons don't like the outdoors and require a lot of gain. And dynamics require a lot of clean gain in most cases. Some ribbons have additional electronics that need power. But neither of those do well without proximity because of the gain requirement which can induce a lot of noise to go with a lot of gain. Which makes them ill suited in most cases.

With film (video), it's more about the illusion as most are more familiar with the illusion than reality. So sounding natural for all intents is an illusion, and not how it actually sounds. i.e. Drawing attention to the story, and not the distractions. In the studio you generally have one mic per sound source. Out and about, you might have a lavalier, boom mic, shotgun on the camcorder and perhaps a stereo pair near by to capture the ambiance. Even with only ONE subject matter. And mix to taste. Or synthesize the whole thing in post if needed. You are for all practical purposes telling a story, not recording an event. Treating it like an event can reduce the post production, but may be not produce the ideal result. Compromises abound. Time versus budget versus skills versus the world...