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Gear / Technical Help => Microphones & Setup => Topic started by: splumer on May 13, 2010, 03:26:45 PM
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I'd like some opinions. I have at my disposal two sets of mics, one a pair of Beyerdynamic MCE 86 shotguns, and the other a pair of Sennheiser ME66/K6 shotguns. At the end of the month I plan on recording moe. and Rusted Root at the Tower City Amphitheater in Cleveland, and I can't decide which ones to use. The Sennheisers use battery power and the Beyers don't, which really isn't an issue, since my recorder, a PMD660, runs the Beyers almost 3 hours on cheapo batteries. I looked at the polar pattern diagrams and the frequency response diagrams to decide which to use, but the Sennheisers list the response in dBv, whereas the Beyers are in straight dB.
OK, so I guess this might be a two part question. How do I compare the two diagrams when they are in different units, and which mics should I use? The venue is outdoor, but I have windscreens for boths, and shockmounts. I'm thinking I might want to do one segment with one set, then the other with the other set, to compare the two. Opinons, gentlemen? (and ladies...)
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You can directly compare the graphs. Each graph will show the mic’s deviation from some zero point at a particular frequency so you may be able to get an idea of the mic’s tonal balance. Most often this zero point is the mic’s level at 1000 Hz.
The Sennheiser graph gives absolute output levels at a particular frequency since it gives a reference level, in this case dBv, or the level relative to 0.775 V. Most of the time dBv is now written dBu so that it will not be confused with dBV, which is the level relative to 1 V.
Rather than pouring over graphs, your best way to pick the mic to use … is to use the mics, and listen to the result. However even this test is not definitive because in some cases mic “S” may work better, in other situations mic “B” may sound the best. And of course mic placement is a huge factor, as well as the sound system you play the recording on, and the room, and many other factors.
The good news is these mics are of a comparable good quality so you should be able to get a good recording using either model.
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Just a side note--dBV is always relative to 1 Volt. The V should be upper-case because it derives from a proper name (Volta), just as the B should be upper-case because it derives from the name Bell. The meaning wouldn't be changed if someone didn't use upper-case, but it would reflect on the user's lack of engineering literacy.
dBu is always relative to 0.775 Volt. The u should be lower-case; etc., etc., etc.
dBm is the one that has been misused a lot. It has fallen out of favor for audio in recent years, since we don't use impedance matching or 600 Ohm loads any more. It means "dB relative to 1 mW" with a 600 Ohm load implied, since this scale (like the dB on which it is based) comes to us from Western Electric and the Bell System. 0 dBm is reached at 0.775 Volt BUT it isn't a voltage measurement; it's a power measurement. For years after impedance matching and 600-Ohm loads were as dead as doornails, audio people still tried to use dBm as if it was a voltage measurement. That's why dBu was invented--it's a voltage measurement that takes no account of load impedance.
-- pedantic best regards
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If I understand correctly, that would mean conversion between units can be done by simply mulitplying one unit by the conversion factor.
dBu = dBV x 0.775
and
dBV = dBu x 1.29
Correct?
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If I understand correctly, that would mean conversion between units can be done by simply mulitplying one unit by the conversion factor.
dBu = dBV x 0.775
and
dBV = dBu x 1.29
Correct?
I don't think so (but, of course, I may be wrong). The dB measurements are logarithms of ratios so you would have to multiply the denominator of the ratio by a conversion factor then take the logarithm of the result (assuming that the reference voltage, 0.775 or 1, is the denominator)...No sense in doing that, though, since you would need to know the signal voltage to form the ratio and, knowing that, you could then just switch the reference voltage.
EDIT TO ADD: It occurred to me that the difference between the two should be a constant...~2.214 dB if my math is right...
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If I understand correctly, that would mean conversion between units can be done by simply mulitplying one unit by the conversion factor.
dBu = dBV x 0.775
and
dBV = dBu x 1.29
Correct?
I don't think so (but, of course, I may be wrong). The dB measurements are logarithms of ratios so you would have to multiply the denominator of the ratio by a conversion factor then take the logarithm of the result (assuming that the reference voltage, 0.775 or 1, is the denominator)...No sense in doing that, though, since you would need to know the signal voltage to form the ratio and, knowing that, you could then just switch the reference voltage.
EDIT TO ADD: It occurred to me that the difference between the two should be a constant...~2.214 dB if my math is right...
This is correct. Because dB are on a log scale, ratios become additive. So just add 2.2 dB to dBV to get dBu, and subtract 2.2 dB from dBu to get dBV.
But for the OP, what matters isn't absolute sensitivity at a given frequency, but the shape of sensitivity vs. frequency. But looking at graphs can only tell you so much especially when measured by different companies who may use different techniques and/or tolerances.
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I suspected the ratio/log business would mean there was more to it.
Thanks for walking me through.
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I think the other responses covered your first question on specs well. If your really trying to compare directly, the problem with running one pair the first set or group and the other pair duing the second set is usually the soundguy takes part of the first half of the first set to correctly set the sound. I would try to find a second deck and compare or set your mics up and let someone else use be the lead deck on the second pair of mics. Let me know if you post I would like to hear the difference.
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I think the other responses covered your first question on specs well. If your really trying to compare directly, the problem with running one pair the first set or group and the other pair duing the second set is usually the soundguy takes part of the first half of the first set to correctly set the sound. I would try to find a second deck and compare or set your mics up and let someone else use be the lead deck on the second pair of mics. Let me know if you post I would like to hear the difference.
That would be ideal, but I don't think I'll be able to. I will switch mics between bands, though.
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I think the other responses covered your first question on specs well. If your really trying to compare directly, the problem with running one pair the first set or group and the other pair duing the second set is usually the soundguy takes part of the first half of the first set to correctly set the sound. I would try to find a second deck and compare or set your mics up and let someone else use be the lead deck on the second pair of mics. Let me know if you post I would like to hear the difference.
That would be ideal, but I don't think I'll be able to. I will switch mics between bands, though.
The Idea I purpose would not be ideal wither however I'll suggest it any way:
got to a show that you don't care too much about- or s free show, run both mics together- one int the left channel the other in the right, Beyer left, sennheiser right. it wouldn't be exactly ideal, or accurate
however you can listen to each mic singularly and do a comp that way.
I take it that you like the way shotguns sound? While I have heard excellent recordings with guns, I'd opt for being closer with spaced omnis pair of DINa or ORTF Cards. or blumlein figure 8's.
since you have the guns try them out in some comps before then, you could even run a few songs with one pair, and swap them out run a few with the other pair and take notes and do a careful listen. posting a comp could give others the chance to comment on what they like and why.
but we all like different flavors of m mics, and all have different ears and different preferences
go with what you like!
peace
--Ian
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I think the other responses covered your first question on specs well. If your really trying to compare directly, the problem with running one pair the first set or group and the other pair duing the second set is usually the soundguy takes part of the first half of the first set to correctly set the sound. I would try to find a second deck and compare or set your mics up and let someone else use be the lead deck on the second pair of mics. Let me know if you post I would like to hear the difference.
That would be ideal, but I don't think I'll be able to. I will switch mics between bands, though.
I take it that you like the way shotguns sound? While I have heard excellent recordings with guns, I'd opt for being closer with spaced omnis pair of DINa or ORTF Cards. or blumlein figure 8's.
peace
--Ian
I've only ever done one show with guns (not these). It's just that these mics are far and away better than what I have, and I can borrow them from work. We also have a Schoeps shotgun, but alas, only one.
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As it turns out, I was only able to get the Beyers, but I was very happy with them.
http://bt.etree.org/details.php?id=535480
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I'd much rather use the beyers.... I've had both and sold the senn me set... I reallly like the akg 568s for shotguns n music
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I'd much rather use the beyers.... I've had both and sold the senn me set... I reallly like the akg 568s for shotguns n music
LOL :laugh:
The post before yours was about 18 months ago - it's all done and dusted by now. :laugh: ;D
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I'd much rather use the beyers.... I've had both and sold the senn me set... I reallly like the akg 568s for shotguns n music
LOL :laugh:
The post before yours was about 18 months ago - it's all done and dusted by now. :laugh: ;D
I agree about the AKGs. I almost bought a pair a few years back :) But since I have some kickass hypers, Im pretty much covered in that aspect!
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John Willett, still can be value bringing new info or opinion to older threads...... net does it real reel good, too