Page 1 of 2 12 LastLast
Results 1 to 25 of 31

Thread: microphone feedback cures

  1. #1
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default microphone feedback cures

    As a pickup alternative, tried miking my guitar yesterday. If I can make it work, I'll try it on mando and other instruments.

    I had the mic run straight into a PA, with nothing in between. (I have one of those round soundhole covers, but I didn't have it with me.)

    It was a disaster. Howling feedback no matter what I did. Finally gave up and plugged in the guitar.

    What are ways to discourage feedback?

    Thanks!

    cb
    Gibson A-Junior snakehead (Keep on pluckin'!)

  2. #2
    Registered User
    Join Date
    Jun 2005
    Location
    High Peak - UK
    Posts
    4,172

    Default Re: microphone feedback cures

    1) Turn it down.
    2) A more directional mic.
    3) Position of the mic. in relation to the instrument.
    4) Play (further) behind the speakers.
    5) Parametric (or other) EQ.
    6) Some sort of feedback destroyer in the signal chain - Behringer used to make quite a good cheap one.
    7) Position of the speakers in relation to the room you’re playing in.

    I think those are the main ones.

  3. The Following 5 Users Say Thank You to Ray(T) For This Useful Post:


  4. #3
    Likes quaint instruments poul hansen's Avatar
    Join Date
    Jun 2020
    Location
    Danmark
    Posts
    725

    Default Re: microphone feedback cures

    I have an Irig Acoustic Stage which has a small microphone for the soundhole and a preamplifier to click on the strap or belt. It has 10 antifeedback filters. You turn up the volume until it howls, press the filter button, turn up.... and so on.

    It also has some modelling for the sound. On top of that, it can learn the characteristics of your instrument with a calibrate function.
    Kentucky KM-805..........2 Hora M1086 Portuguese II(1 in car)
    Hora M1088 Mandola.....
    Richmond RMA-110..... .Noname Bearclaw
    Pochette Franz Janisch...5 Pocket............Alfredo Privitera pocket
    Puglisi Pocket 1908........Puglisi 1912.......Puglisi 1917
    3 Mandolinetto ..............C.Garozzo
    1 Mandriola...................Cannelo G. Mandriola...Böhm Waldzither 1921
    Johs Møller 1945............Luigi Embergher Studio 1933
    Marma Seashell back......Luigi Embergher 5bis 1909

  5. The following members say thank you to poul hansen for this post:


  6. #4
    Unfamous String Buster Beanzy's Avatar
    Join Date
    Sep 2009
    Location
    Cornwall & London
    Posts
    2,921
    Blog Entries
    5

    Default Re: microphone feedback cures

    I use two methods as I swap between mandolin & fiddle a lot.
    1: Very close mic omni lavaliere mounted behind the bridge. (Sony ECM77 or Rode SmartLav+ depending on situation & desk person)
    2: AKG C1000s mounted overhead with the rear lobe pointing ceiling wards around the 45degree mark depending on the ceiling height. Sometimes I go closer and take the hyper-cardoid capsule out.
    Eoin



    "Forget that anyone is listening to you and always listen to yourself" - Fryderyk Chopin

  7. The following members say thank you to Beanzy for this post:


  8. #5
    Registered User
    Join Date
    Mar 2013
    Location
    Brooklyn, NY, USA
    Posts
    1,249

    Default Re: microphone feedback cures

    A bit more information would be helpful. What kind of microphone and how is it mounted? How loud are you playing. Were are you in relation to the speakers.

  9. The following members say thank you to Nevin for this post:


  10. #6

    Default Re: microphone feedback cures

    Put a third octave EQ in line, turn up till it feeds back, notch that frequency down...repeat.

  11. The following members say thank you to Joed for this post:


  12. #7
    Registered User
    Join Date
    Jun 2011
    Location
    Germany
    Posts
    132

    Default Re: microphone feedback cures

    Yes, give us some more information about playing style, volume, stage volume, microphone, mic position, monitors on stage, other instruments on stage ...

    I perform and do live sound , acts are bluegrass, folk, singer/songwriter, acoustic jazz ... I always work on my live rig for the best possible acoustic sound on acoustic guitar, mandolin, banjo, dobro, bouzouki. Although I made sound for classy bluegrass acts micing each instrument separately or using only one mic on stand for the whole band with great results I never could find a way to use only one mic in front of my instruments, always lacking cutting through power on guitar. Although I play pretty loud on a powerful dread, use a decent microphone and personal monitor. Settings are acoustic trio up to six-person line up including drums, stage volume is moderate, venues are 100 to 500 people clubs and open air. So I opted to use an additional pickup on guitar whereas mandolin and banjo play into the mic on a boom stand. I first dial in the right level for mandolin and then add a bit the pickup from the guitar.

    Some advice to eliminate feedback when using a mic in front of an acoustic guitar:
    - Start with the mic pointing at the 14th fret as close as possible for optimum gain before feedback
    - a mic with flat frequency helps reduce high end feedback (or bring down the treble a bit without sacrificing airiness from the mic)
    - some significant low frequency roll off up to 200 Hz helps reduce low end feedback and boomy, muddy bass content.
    - a flat response monitor with some low freq roll off properly placed (off-axis to mic) helps
    - try reduce stage volume
    - stay behind the main speaker line as far as possible
    - avoid bandmates who need to be loud on stage (I know what I'm talking about)
    - every venue needs its own treatment / EQ

    This is from my experience, maybe there is something helpful for you.

    Cheers,
    Robert
    Ellis F5 Special Deluxe custom
    Anton Krutz F5
    Lawrence Smart H 5 Mandola
    Gibson K 2 Mandocello
    Northfield mahogany arch top Octave Mandolin

    guitars, banjo, dobro, weissenborn, pedal steel, fretless bass, upright bass

  13. The Following 2 Users Say Thank You to mando-bob For This Useful Post:


  14. #8
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by Ray(T) View Post
    1) Turn it down.
    2) A more directional mic.
    3) Position of the mic. in relation to the instrument.
    4) Play (further) behind the speakers.
    5) Parametric (or other) EQ.
    6) Some sort of feedback destroyer in the signal chain - Behringer used to make quite a good cheap one.
    7) Position of the speakers in relation to the room you’re playing in.

    I think those are the main ones.
    1. We tried turning it down.

    2. It's a super-cardioid mic.

    3. I had it about eight inches from the twelfth fret. Too close?

    4. I was behind the speakers.

    5. Hm. I'll look up "parametric EQ."

    6. I'll look up "feedback destroyer."

    7. It was an odd practice space - and insulated garage loft.

    Thanks, Ray!
    Gibson A-Junior snakehead (Keep on pluckin'!)

  15. #9
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by poul hansen View Post
    I have an Irig Acoustic Stage which has a small microphone for the soundhole and a preamplifier to click on the strap or belt. It has 10 antifeedback filters. You turn up the volume until it howls, press the filter button, turn up.... and so on.

    It also has some modelling for the sound. On top of that, it can learn the characteristics of your instrument with a calibrate function.
    Thanks, Poul. I'm not looking to buy gear now. I have almost no experience miking acoustic instruments, so I suspect I was just doing it wrong.
    Gibson A-Junior snakehead (Keep on pluckin'!)

  16. #10
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by Nevin View Post
    A bit more information would be helpful. What kind of microphone and how is it mounted? How loud are you playing. Were are you in relation to the speakers.
    It's a Sennheiser e945. I mounted on a mic stand and aimed it down toward the guitar. I was sitting, so the guitar was lower than the mic.

    Not loud. And it fed back even when I wasn't playing. The only thing that stopped the feedback was to put my hand over the soundhole.

    I was behind the speakers.
    Gibson A-Junior snakehead (Keep on pluckin'!)

  17. #11
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by mando-bob View Post
    Yes, give us some more information about playing style, volume, stage volume, microphone, mic position, monitors on stage, other instruments on stage ...

    I perform and do live sound , acts are bluegrass, folk, singer/songwriter, acoustic jazz ... I always work on my live rig for the best possible acoustic sound on acoustic guitar, mandolin, banjo, dobro, bouzouki. Although I made sound for classy bluegrass acts micing each instrument separately or using only one mic on stand for the whole band with great results I never could find a way to use only one mic in front of my instruments, always lacking cutting through power on guitar. Although I play pretty loud on a powerful dread, use a decent microphone and personal monitor. Settings are acoustic trio up to six-person line up including drums, stage volume is moderate, venues are 100 to 500 people clubs and open air. So I opted to use an additional pickup on guitar whereas mandolin and banjo play into the mic on a boom stand. I first dial in the right level for mandolin and then add a bit the pickup from the guitar.

    Some advice to eliminate feedback when using a mic in front of an acoustic guitar:
    - Start with the mic pointing at the 14th fret as close as possible for optimum gain before feedback
    - a mic with flat frequency helps reduce high end feedback (or bring down the treble a bit without sacrificing airiness from the mic)
    - some significant low frequency roll off up to 200 Hz helps reduce low end feedback and boomy, muddy bass content.
    - a flat response monitor with some low freq roll off properly placed (off-axis to mic) helps
    - try reduce stage volume
    - stay behind the main speaker line as far as possible
    - avoid bandmates who need to be loud on stage (I know what I'm talking about)
    - every venue needs its own treatment / EQ

    This is from my experience, maybe there is something helpful for you.

    Cheers,
    Robert
    All good. Thanks!
    Gibson A-Junior snakehead (Keep on pluckin'!)

  18. #12
    Registered User
    Join Date
    Jan 2009
    Location
    S.W. Wisconsin
    Posts
    7,507

    Default Re: microphone feedback cures

    Put the mic closer to the guitar so it doesn't have to be as loud. 2" would be the most. I would also not be at the 12th fret, but at the fingerboard extension with a slight angle toward the sound hole. NEVER mic the sound hole. Every room has resonant frequencies, 250 hz is one in almost every room. Take the EQ for that and bring it down, it will clean up all the sound and help the guitar from booming. A parlor guitar will mic better than a dreadnought too.
    THE WORLD IS A BETTER PLACE JUST FOR YOUR SMILE!

  19. The following members say thank you to pops1 for this post:


  20. #13

    Default Re: microphone feedback cures

    Super/hyper-cardioid mics do have a small lobe in their polar pattern. I've found that can be a problem if the gain is high and/or there's any PA or stage monitor at enough volume to be picked up. So, try the old trust SM57 and as others say, get it real close if you need to, but *guitar* is going to be a problem. You need to have the EQ set to roll off the low end pretty high to remove as much LF as possible, and if there's a bass amp in the picture, get the soundhole plug in.
    2018 Kentucky KM-950, 2017 Ellis A5 Deluxe

  21. The following members say thank you to keith.rogers for this post:


  22. #14
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by keith.rogers View Post
    Super/hyper-cardioid mics do have a small lobe in their polar pattern. I've found that can be a problem if the gain is high and/or there's any PA or stage monitor at enough volume to be picked up. So, try the old trust SM57 and as others say, get it real close if you need to, but *guitar* is going to be a problem. You need to have the EQ set to roll off the low end pretty high to remove as much LF as possible, and if there's a bass amp in the picture, get the soundhole plug in.
    Didn't try rolling off the bass. Will do! And there is indeed a bass amp in the picture. Next time, I'll try using my soundhole plug, too.

    Don't have a 57 handy.
    Gibson A-Junior snakehead (Keep on pluckin'!)

  23. #15

    Default Re: microphone feedback cures

    Quote Originally Posted by Charlie Bernstein View Post
    Didn't try rolling off the bass. Will do! And there is indeed a bass amp in the picture. Next time, I'll try using my soundhole plug, too.

    Don't have a 57 handy.
    I didn't quite clarify that it's the small lobe at the back of the polar pattern that can create problems. It the mic is pointed down, it may not be an issue, but I prefer cardioid patterns (SM57, SM58, e835, et al.), in general.

    The super-cardioid's tighter front pattern can be better in situations where the stage volume is high, but the mic is going to be very close-mic'd, e.g., a hand-held vocal mic right in front of the singer's lips, and, especially, not where that back lobe can pickup anything [relatively] significant. They also tend to be further from wedge monitors in those situations, too. (I had a Beta57a in front of an amp once that sounded great in the studio setting, but live turned out to be a mistake - I had a bit of everything coming out of the floor monitor in the guitar track, with a teensy delay - not easy to mask! But, I digress...)
    2018 Kentucky KM-950, 2017 Ellis A5 Deluxe

  24. The following members say thank you to keith.rogers for this post:


  25. #16
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by keith.rogers View Post
    I didn't quite clarify that it's the small lobe at the back of the polar pattern that can create problems. It the mic is pointed down, it may not be an issue, but I prefer cardioid patterns (SM57, SM58, e835, et al.), in general.

    The super-cardioid's tighter front pattern can be better in situations where the stage volume is high, but the mic is going to be very close-mic'd, e.g., a hand-held vocal mic right in front of the singer's lips, and, especially, not where that back lobe can pickup anything [relatively] significant. They also tend to be further from wedge monitors in those situations, too. (I had a Beta57a in front of an amp once that sounded great in the studio setting, but live turned out to be a mistake - I had a bit of everything coming out of the floor monitor in the guitar track, with a teensy delay - not easy to mask! But, I digress...)
    The only reason I got the Senn was to mic instruments on stage.

    Is a 57 better for on-stage miking? Or should I just quit trying to mic instruments on stage?
    Gibson A-Junior snakehead (Keep on pluckin'!)

  26. #17
    Registered User
    Join Date
    Jun 2005
    Location
    High Peak - UK
    Posts
    4,172

    Default Re: microphone feedback cures

    Quote Originally Posted by Charlie Bernstein View Post
    1. We tried turning it down.

    2. It's a super-cardioid mic.

    3. I had it about eight inches from the twelfth fret. Too close?

    4. I was behind the speakers.

    5. Hm. I'll look up "parametric EQ."

    6. I'll look up "feedback destroyer."

    7. It was an odd practice space - and insulated garage loft.

    Thanks, Ray!
    1) Cardioid (i.e. “heart shaped”), super-cardioid, hyper-cardioid - progressively more directional and pick up less from the sides and back.

    2) 8 inches sounds about right - it’s largely a matter of “try it and see”.

    3) Parametric EQ - difficult to explain without diagrams. A graphic EQ splits the audo spectrum into frequency bands and you can boost or cut each one - mainly cut the one which is feeding back and the more knobs the better. A parametric has far fewer knobs - possibly three, five or more sets. Simple ones have knob in each set to boost or cut, a knob which adjusts the central frequency which is boosted or cut and a third which widens or narrows the range around the central frquency being boosted or cut (usually known simply as the “Q”). If you’re not used to setting one, you can make a make a complete mess of the sound!

    4) A feedback destroyer is simply an automatic parametric EQ. Generally, as you turn up the level and things start to feed back, a filter is automatically turned on to cut the feedback frequency. Continue turning it up and another one cuts in etc etc until you run out of filters. They’re usually used on a complete sound mix rather than individual instruments and you plug them in between the mixing desk and power amps.

    5) Rooms can be unpredictable. Placing speakers in corners can increase bass frequencies. Moving them away from walls can affect the sound and there’s a concert hall down the road from me where, with loud rock bands, people have reported suffering from bleeding ears when sitting beneath the balcony!

    R

  27. The following members say thank you to Ray(T) for this post:


  28. #18
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by Ray(T) View Post
    1) Cardioid (i.e. “heart shaped”), super-cardioid, hyper-cardioid - progressively more directional and pick up less from the sides and back.

    2) 8 inches sounds about right - it’s largely a matter of “try it and see”.

    3) Parametric EQ - difficult to explain without diagrams. A graphic EQ splits the audo spectrum into frequency bands and you can boost or cut each one - mainly cut the one which is feeding back and the more knobs the better. A parametric has far fewer knobs - possibly three, five or more sets. Simple ones have knob in each set to boost or cut, a knob which adjusts the central frequency which is boosted or cut and a third which widens or narrows the range around the central frquency being boosted or cut (usually known simply as the “Q”). If you’re not used to setting one, you can make a make a complete mess of the sound!

    4) A feedback destroyer is simply an automatic parametric EQ. Generally, as you turn up the level and things start to feed back, a filter is automatically turned on to cut the feedback frequency. Continue turning it up and another one cuts in etc etc until you run out of filters. They’re usually used on a complete sound mix rather than individual instruments and you plug them in between the mixing desk and power amps.

    5) Rooms can be unpredictable. Placing speakers in corners can increase bass frequencies. Moving them away from walls can affect the sound and there’s a concert hall down the road from me where, with loud rock bands, people have reported suffering from bleeding ears when sitting beneath the balcony!

    R
    1. Oh. I thought it went cardioid > hyper-cardioid > super-cardioid. (So can Hyperman beat up Superman?)

    2. Yup. I tried it and didn't like what I saw. Or heard.

    3. Good to learn, even though I'm not gear shopping.

    4. See 3.

    5. Fer sher!

    Thanks!
    Gibson A-Junior snakehead (Keep on pluckin'!)

  29. #19
    Registered User jefflester's Avatar
    Join Date
    Jul 2003
    Location
    California
    Posts
    2,474

    Default Re: microphone feedback cures

    Quote Originally Posted by Ray(T) View Post
    1) Cardioid (i.e. “heart shaped”), super-cardioid, hyper-cardioid - progressively more directional and pick up less from the sides and back.
    But as mentioned above, hypercardiod (and supercardiod as well) develops a lobe out the back.

    Click image for larger version. 

Name:	polar-patterns.jpg 
Views:	70 
Size:	58.8 KB 
ID:	197966

  30. The following members say thank you to jefflester for this post:


  31. #20

    Default Re: microphone feedback cures

    Kind of high-level overview of polar patterns from Shure.
    https://www.shure.com/en-US/performa...pattern-basics

    The point about the “printed” polar pattern vs frequency is important. Many patterns show only a single frequency. Your feedback problem is likely pretty low and the mic may be not so directional there. It’s the reason pickups were invented .

  32. The following members say thank you to keith.rogers for this post:


  33. #21
    Registered User
    Join Date
    Jun 2005
    Location
    High Peak - UK
    Posts
    4,172

    Default Re: microphone feedback cures

    Yes, printed patterns are only a guide it’s how a mic actually works that matters. Don’t assume that a mic responds to all frequencies equally (a so-called flat response). Some mics are even valued for their quirky response patterns.

  34. The following members say thank you to Ray(T) for this post:


  35. #22

    Default Re: microphone feedback cures

    The Sennheiser has a pop filter for vocals, though it's fine for instruments. A 58 is more comparable. 58s and 57s are about the same but the 58 has a pop filter for vocals and it's superior to the 57 for that use.

  36. The following members say thank you to Joed for this post:


  37. #23
    coprolite mandroid's Avatar
    Join Date
    Oct 2002
    Location
    Outer Spiral Arm, of Galaxy, NW Oregon.
    Posts
    17,103

    Default Re: microphone feedback cures

    Maybe Stage Craft ? move things around up there until it stops? in-ear monitors, maybe?
    writing about music
    is like dancing,
    about architecture

  38. The following members say thank you to mandroid for this post:


  39. #24
    Registered User
    Join Date
    Aug 2013
    Location
    Va
    Posts
    2,573

    Default Re: microphone feedback cures

    Micing acoustic instruments is the only way I’ll go, pick-ups produce an unnatural sound in my opinion, due to proximity of pick-up to soundboard. Put your ear against guitar and pick a song, hear how different guitar sounds??
    Having said that if you are going to mic instruments you need to educate yourself on amplifying sound, which is a life-long study. But you combine education with experience. Each gig you set up, will be eaiser. Each gig will be different. The biggest variable is room acoustics, but you learn to “ read” a room and adjust accordingly as you get more experience. Listen to EVERYONES advice but with a grain of salt. What works is what works rather it follows the “rules” or not

  40. The following members say thank you to Mandoplumb for this post:


  41. #25
    Registered User Charlie Bernstein's Avatar
    Join Date
    Aug 2015
    Location
    Augusta, Maine, USA
    Posts
    1,814

    Default Re: microphone feedback cures

    Quote Originally Posted by Ray(T) View Post
    Yes, printed patterns are only a guide it’s how a mic actually works that matters. Don’t assume that a mic responds to all frequencies equally (a so-called flat response). Some mics are even valued for their quirky response patterns.
    Yup. For instance, I used an EV RE20 for recording a few times. It just sounded good.* There's probably a diagram that explains why. Go figure!

    ---------

    * Real good.
    Gibson A-Junior snakehead (Keep on pluckin'!)

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •