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Ribbon mics and quiet sound sources

Discussion in 'Microphones' started by BobRogers, Jun 22, 2009.

  1. BobRogers

    BobRogers Well-Known Member

    So last night I was recording lightly picked guitar (both nylon and steel string in turn) with Beyer 130/160 in MS. The guitarist uses primarily the pads of his fingers and his sound is pretty quiet (he's used to playing amped). I like the sound I got best with the pair about two feet away, but at this distance I had my API 3124 cranked pretty much all the way. At that volume the noise floor is pretty easy to hear during the count in and as the tails decay at the end of the song (at least on Sony headphones - which tend to be pretty bright). The recorded level is less than -60 dBfs.

    With this song, the picking is pretty constant and the noise is not audible (to my ears) during the song. So this is going to be pretty easy to take care of. But I'd like to know what strategies you have employed in more difficult situations. In general, I'm excited about the sound I'm getting, so I'm not too interested in, say, buying a new preamp (though any suggestions are welcome). Mostly in how people deal with this during mixing. Noise reduction software? Downward expansion? Should it be handled in individual tracks or left for mastering?
     
  2. Guitarfreak

    Guitarfreak Well-Known Member

    I'll start by saying I have no experience with the situation that you just described. However, it does seem that if you are having trouble with a track that was mic'd at a distance, then just don't use that track.

    The fact seems that he just isn't picking hard enough to stand out from the room/electrical noise at that distance. It seems that distance/room miking is not conducive on such a quiet source.

    Just my ¢02
     
  3. Cucco

    Cucco Distinguished Member

    Hey Bob -
    How's that pair working out for you?

    In my experience, this is a pretty easy thing to handle - one of a few ways.

    The first, and perhaps easiest, is noise reduction software. Any of the usual suspects in this arena will work. Because, ultimately, the source is not that complicated, a bit of judicious NR can be very helpful without imparting any noticable artifacts. (I HATE NR artifacts!) Of course, in doing so, you're likely to roll off a bit of the upper frequencies. These may need to be EQ'ed back in, but can usually be done without slaughtering the sound of the instrument.

    Second, more time consuming, you can separate out the parts of the track that are exposed and thus more likely to be heard in the mix, then do just your NR on these portions. You can usually get away with a bit more NR on these portions especially if they're not complex. If there's rumble, you can use a more aggressive HPF on these portions and a more gentle one when it's in the mix.

    I wouldn't resort to a gate or expander - you'll find the magically-appearing-hiss to be rather distracting and annoying.

    Of course, my solution is almost always:
    "Embrace the noise." I've definitely learned that we, the engineers, are far more sensitive to it than the consumers in general.

    Cheers-
    J.
     
  4. Codemonkey

    Codemonkey Well-Known Member

    "Embrace the noise."

    +1
    I could post a short clip of the noise floor I get to deal with...
     
  5. BobRogers

    BobRogers Well-Known Member

    They are working great. Mando, dobro, congas, bongos, acoustic guitars, they have definitely been the favorite around here. Enough of a favorite that I've been reluctant to give them up when a hotter mic would make my life a little easier.

    With this particular song the noise issue is very easy to take care of even without noise reduction software by trimming the count in and fading the tail at the end. I've been putting moise reduction software off because I hear so many "you get what you pay for" comments. Something to look at in the future maybe. I could have reduced the problem by moving the mic closer, but it's not really the best spot for it. If I had a piece with a lot of long ringing tails it might have been the best compromise, but this was steady fingerpicking. (Alice had this guy in mind when she chose that piece for the tests.)
     
  6. RemyRAD

    RemyRAD Guest

    Bob, one of the reasons why I like to EQ while tracking is exactly the reason that you described. Preemphasis & Deemphasis has been used since the beginning of recording history to reduce high frequency noise, in particular. So had you kicked up a few DB@10-12kHz, a reciprocal rolloff would have provided you with much-needed noise reduction. Of course at the expense of the linear phase response but then who's counting? Frequency response would be virtually unaffected. Of course that does not quite work out with API 550-A's since they're not reciprocal in their operation. Not in the typical sense that is. But then I'm talking to my computer who is looking at me like I'm crazy. My kitty died and so now, all I have to talk to is my computer and if she begins to purr, I had better have my hard drive backed up. So you're using one of my favorite combinations. But yeah, you definitely will pick up some noise like that. So, move them in a little closer maybe?

    This is why I flunked math
    Ms. Remy Ann David
     
  7. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    Long ago I recorded a piece called the King of Denmark by Morton Feldman. Here is description of the piece from the WWW:In many ways, The King of Denmark is an anti-percussion piece. It is to be played very softly using only the hand and fingers - no sticks or mallets. Its notation on a graph indicates how many sounds are to be played per beat and whether they are to be in high, medium, or low registers. Even though a tempo runs throughout, no rhythmic coherence emerges. Sounds simply float out, detached and weightless. One instrument has no more sonic gravity than another does. A small bell weighs the same - takes up the same acoustical space - as a large gong. An auditory illusion follows: close your eyes and you can imagine that the instruments are being played at their natural volumes. They are sounds in many different loudnesses, but they are being heard from different distances. The gong is really forte but it is heard from the distance of fifty yards. It sounds as soft as the little bell six inches from your ear. Mirages of distance appear and evaporate again into music. It is like rain or the sound of rain.

    I recorded it with 2 RCA 77DX microphones and an Ampex AG440 tape deck. The piece is so quiet that the performers breathing is sometimes louder than the percussion he is playing. It is an amazing piece but getting it to tape was very difficult. I finally used the quietest microphone preamps I had (It was a custom built rig using TranzAmp modules) and directly into the tape deck. The sound was amazing and the performance was perfect. Yes there is a little hiss and yes some electronic noise but the sound the the recording overwhelms the noise problems. If I had to do it today I would probably do it the same way only I would use a couple of Blue "Robbie" preamps which are the quietest most neutral sounding preamps around.
     
  8. BobRogers

    BobRogers Well-Known Member

    Good point. That would have helped a lot. Next time I may use the Langevin DVC and boost the HF, then compensate in the box.
    Real sorry to hear that.
    Definitely one of mine now as well. And moving closer is definitely the sensible thing to do. I liked the sound of the guitar best where I put it, but closer isn't that bad. It's the right compromise.
     
  9. BobRogers

    BobRogers Well-Known Member

    That's a cool story. I'll have to keep an eye out for a recording of the piece. If I were doing more serous classical recording I'd probably be investigating quieter preamps, but for the type of folk/jazz/pop things that I record I really like the API. I think that if I increase the number of good preamps in my rig I'll keep moving in that direction.
     
  10. Boswell

    Boswell Moderator Distinguished Member

    Applying EQ during the recording process (pre-emphasis/de-emphasis) can only help to compensate for noise in the recording medium (tape, vinyl etc). The noise of the pre-amp first stage is part of the signal from the output of the first stage onwards and cannot be separated from wanted signal. By all means roll off the top end to reduce the hiss, but you will roll off signal as well. You can post-process the recording with noise-reduction algorithms, but the only real way to alleviate the trouble is to use a low-noise pre-amp in the first place.

    It's for exactly this situation of wanting to use low-output ribbon mics with standard high-quality pre-amps that I designed a fully-differential phantom-powered pre-pre-amp with fixed 20dB gain and very low input noise. The unit was supposed to be in production by now, but the company who commissioned it have put it on the back burner (citing recessionary times). The prototype I have works well with all the ribbons I have tried it on.
     
  11. RemyRAD

    RemyRAD Guest

    Oh sure Boswell old boy. I once just considered removing the capsule from my U87 & connecting one of my ribbons instead. And voilà, we now have all of these "active ribbons" that sound more like condenser microphones than condenser microphones. Not that it's a bad concept, we would all like them lower in noise, higher in output. But then I don't think anybody has released a ribbon microphones with a neodymium magnetic structure yet? I might be wrong about that but, it's a recent thing. That would certainly up the output level. Like the difference between the SM58 & the Beta 58. The beta sounds more like a condenser microphone than the SM. So better just means different. So why not just make a generic module powered by phantom for any ribbon microphone? Call it a RIBBON BOOSTER. Yeah, that's the ticket. And what's it going to cost me in US dollars? I know your good.

    I'm all excited now! Look what you've done to me.
    Ms. Remy Ann David
     
  12. Boswell

    Boswell Moderator Distinguished Member

    I think that's exactly what the company who commissioned the design had in mind - an attempt to ride the market for the growing popularity of ribbon mics, targeting those whose pre-amps don't have enough gain. I'm disappointed that the device hasn't been released yet, but we'll see what happens.

    The gain section of the device was relatively straightforward, but more than half the circuitry is protection of the mic against random phantom power cycling and any single component fault. Testing that last requirement was fun, but my trusty Beyers and B+O ribbons are still intact.
     
  13. moonbaby

    moonbaby Mmmmmm Well-Known Member

    Bob:
    If and when you try the Beyers with the DVC, let me know how it goes. I'm getting ready to get a DVC, I've been concerned as to whether it has enough gain for my Beyers.
     
  14. Cucco

    Cucco Distinguished Member

    I've used the Beyers with the DVC with just fine success. The DVC doesn't have enough gain to coax out a loud enough performance on gently picked guitar, but certainly drums, vocals, louder guitars, etc. it works quite well.

    If I recall correctly, there is a simple mod to the DVC that allows you to get more gain out of it when necessary.

    Cheers-
    Jeremy
     
  15. BobRogers

    BobRogers Well-Known Member

    I'm going to be using the Beyers with the DVC tonight, but it's going to be on drums, so that won't give you much info about how it works on low volume sources. The fact that you can add an extra gain stage from the limiter will probably be a big help on low volume sources, but I've never thought of the DVC as a particularly high gain amp.
     

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