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Dirty-South Blues Harp forum: wail on! >
Harp Mic Resistors
Harp Mic Resistors
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congaron
583 posts
Feb 27, 2010
12:18 PM
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"Neither of these is necessarily a bad thing for a harp player tonewise, but comparing the feedback rejection of a stick mic on a mic stand to one tightly cupped is pointless." As Greg even pointed out, cupping a uni-directional mic changes its characteristics. What is not ever known for sure until you try it is how much and in what manner they are affected. Simply saying it becomes an omni is over-simplified at best.
The reason for comparing these is to show the importance of the microphone and how it's variations affect feedback. There was a comment early in the thread implying the microphone is virtually a non-player compared to other factors. The microphone is the first important piece in the signal chain and the comparison to the stick mic on a stand is another piece of the information puzzle. You can indeed cup a stick mic on a stand and frequently without feedback issues.
I think in a discussion like this the only pointless information is whatever gets presented as an absolute. It's all good as long as we remember every stage, every room, every amp, every mic, every speaker and every player is different. Personally, I think the gain vs volume discussion may have done a fly-by on a lot of folks anyway. That's okay by me. There has been plenty of practical information for folks to take from this discussion and easily apply.
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MrVerylongusername
927 posts
Feb 27, 2010
1:18 PM
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With respect Ron, it is not a simplification. I said if you block the rear and side vents it becomes omnidirectional. This is a fact that cannot be disputed. with 100% of the sound energy hitting the front of the mic diaphragm, there is none of the phase cancellation which produce cardioid type polar patterns. It is a matter of how the mics have been engineered and how they are designed to be used. Vocal dynamics are not designed to be cupped. Yes the transition from one pattern to another is relative to how completely the off-axis pickup is blocked, but the traditional ball and stick mic is pretty hard to cup tightly without closing it off completely. I suspect one of the reasons why the EV re-10 is so popular (tone aside) is the fact that it has vents along the handle, making it pretty hard to completely block all off-axis sound.
A hypercardioid mic that can 'hear itself' is going to feedback just the same as an omni that can 'hear itself' it's just a hell of a lot easier to position a hypercardioid so it cannot.
Your implication was that vocal mics make great harp mics because they reject feedback as a result of their polar pattern. When cupped their feedback rejection is to a far greater degree a matter of their frequency response rather than their polar pattern. They become more susceptible to all the issues of placement, resonant room frequencies etc..
Maybe 'pointless' was overstating things and a bad choice of words, but comparing a cardioid type mic on a stand with one tightly cupped is like comparing apples and oranges.
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congaron
587 posts
Feb 27, 2010
4:03 PM
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"There is one instance where feedback can be profoundly affected by mic choice.
A dynamic vocal mic, particularly a unidirectional one, may not feedback at all. My cut-down samson dynamic mic has no feedback issues whatsoever. All my other mics have at least some sort of feedback issue to deal with, whether it's in a small room or on a stage. The samson has none of that. Neither does my beta 57. The amp and speakers i use are the same, so it's a difference in the microphone. I use 12ax7 now in my valve junior because changing to this mic made it possible.
In the world of "harp mics" a mic may make a small difference in feedback, but in the world of vocal mics..well, it's a different world. "
This is my original post. As you can see cupping is not mentioned and the distinction between Vocal mics and harps mics is clearly made. I only gave examples of real-world results and made no mention of whether or not it was the polar pattern or the frequency response that made the difference. I addressed that later and maintain that i don't know or particularly care which one it is. Incidentally the samson is an omni that changed dramatically when I flattened the mesh ball to put the harp closer to the element. Other than cutting down the handle, no other mods were made. It became extremely feedback resistant after that one mod..noticably so.
The amount of air behind the element in ANY unidirectional mic varies your result once you close the back off from the front. It even matters how big your hands are. That is part of the result you will get from making your uni into an "omni" by cupping it too. Because a uni is designed to let more air both out and in the back than an omni resulting in the polar pattern difference, the results also vary from mic to mic when you cup them. I have been all through this in real testing. I have built my own vocal headset and earset mics for years using omni and uni electret elements. I'm well aware of the characteristics of them and how minute changes affect their responses.
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