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[Sandy Flett]

I currently use an AKG C516 clip-on mic to amplify the bass of my melodeon, but often I cannot get it loud enough before feedback starts to creep in. If I put two mics on the bass, going into two separate channels on the mixer, would I get more volume overall, but with each mic working just below its feedback level? Any phasing issues to worry about - ie should they be close to each other or as far apart as possible?

[Chris Brimley]

My first reaction would be that the only way you would get more volume out of it would be if you're not getting an even response across the bass notes, in which case a pair of mikes, if carefully set up, would perhaps allow a more even bass sound.  You would have to be careful with positioning to avoid the phasing issues.  But I think you might well find in practice that a pair of mikes would actually make the feedback problem worse.

But I'd be surprised if this is the answer.  As discussed on other threads (and I do seem to be in a minority here!), I'm afraid that I'm not a fan of close miking systems for the very reason you describe - the small mike's directional performance tends to be just not good enough, IMO.  If you have a look at the mike's polar diagram for different frequencies in the technical stuff, and compare it with that for a larger and more directional free-standing mike you will see the problem - it won't cut off the sound from other angles than where it's pointing.  Therefore it picks up too much sound from the monitor or main speakers at certain frequencies and you get feedback.

There are certain things you can do to minimise the problem, and I'm assuming you've done all this already?  (eg:  Make sure the main speakers are well forward of the band, make sure the mike is positioned so that it points away from the monitors, try to cut out dominant feedback frequencies, don't go so close to the monitors that every slight movement of the box puts it over the edge.)

I've played with violinists and PA players whose playing enjoyment has been ruined by this issue.  The right miking system is the answer, I believe.

[Anahata]

No, two mics won't help. In simple terms, twice the opportunity for feedback.

What you need is a mic closer to the melodeon. A Microvox M400 with the opening pointing into one of the apertures in the bass cover plate will get you plenty of sound. Don't worry that the mic is omnidirectional - you are so close to the sound source that you will still get more sound and less feedback. Also if your feedback is happening at low frequencies, that's because no so-called cardioid mic is actually directional at low frequencies anyway.

Alternative approach: with the AKG C516, if you are getting feedback and the bass end has its own mixer channel, can you not reduce the foldback level on your bass end? (and follow all the other general good advice Chris Brimley has posted, of course)

[Sandy Flett]

Many thanks Chris and Anahata.

I have spent a bit of time experimenting today and have decided to try again with the fixed mic on a stand as I can fix the position of that (and it is definately a nicer acoustic sound than anything very close-in, and gets away from those damned thin wires that catch in everything), but I have also moved my Mackie SRM150 foldback monitor's position to nearer my right ear so it can be lower volume and not in line of sight of the bass mic. But as we all know, home experimenting can count for nothing once you are in the volume levels and gear layouts of a live gig - so I won't know for a couple of weeks whether it is to work.

[Mcgrooger]

I'd say that most of the melodeon based feedback in our band is to do with the monitors, not the main speakers, so be careful where you are in relation to it/them.

[Howard Jones]

For what it's worth. I use a C516 on the treble end and have no problems with feedback. It has cardioid polar pattern, and AKG recommend it for accordion (among other instruments).

[Anahata]

C516 should work well on treble end. Roll off the bass from it, and it the frequencies of interest it's very directional.

For band work, I use a SM57 on a short boom stand for the treble end, and on the bass side I have a Microvox swan neck inside the bass end, with the capsule carefully placed right next to an opening in the end piece so that acoustically it's like a mic on the outside pointing in. The bass mic is wired to a phono (RCA) socket mounted in the back of the melodeon's bass end, and in use a phono-phono cable connects that to a box which also has an XLR for the treble mic, a battery for the bass mic, a fixed attenuator for the bass mic, and a volume control for fine adjustment of the bass level. The box has a male XLR into which you can plug a normal mic cable. It also has blocking capacitors so if phantom power is turned on it doesn't have any detrimental effect. About the only thing missing is the ability to actually run off phantom power if it's there.

It helps that I don't play in any band with very high sound levels on the stage, and I use JBL Control 1s on mic stands for foldback, which means I can have the speaker quite close to my head and the sound level fairly low. It's never fed back. In two smaller bands (a trio and a duo) we don't bother with foldback at all.

My main speakers are EV SX300 and they have the advantage of being quite directional too, so we really don't get a lot of sound off the back of them.