Stutwo Posted September 20, 2006 Share Posted September 20, 2006 Another one for you more experienced lot: I was once told that when using two condenser microphones close to each other (eg a lecturn), you should reverse the phase of one of them. I didn't find it making any difference. Has anyone else heard of this and why was it suggested? Edit: I just realised this is in the lighting forum! Oops. Still, would be interested. Link to comment Share on other sites More sharing options...
Bobbsy Posted September 20, 2006 Share Posted September 20, 2006 ...of course, doing a figure of 8 IS better than simply coiling a cable (cable drums aside). The difference is nothing to do with magnetism, but it does allow the cable to the paid out without the kinking that a simple coil would cause. In my youth putting studio cameras against the wall for the night, we'd have been shot by the supervisor if we didn't figure of 8 the big multicore cables. If you think about it, the figure of 8 configuration is, in effect, creating a flattened version of the "over/under wrap" beloved of us soundies when coiling mic cables. Bob Link to comment Share on other sites More sharing options...
Just Some Bloke Posted September 20, 2006 Share Posted September 20, 2006 I was once told that when using two condenser microphones close to each other (eg a lecturn), you should reverse the phase of one of them. I didn't find it making any difference. Has anyone else heard of this and why was it suggested?I was taught that if putting 2 mics on a lecturn they should both be in the middle pointing past each other to the opposite sides, thus avoiding phase problems. It really works, but you'd be amazed how often people don't do this and put them either side of the lecturn. As the person moves their head round you really can pick up the phase changes. Link to comment Share on other sites More sharing options...
Ekij Posted September 20, 2006 Share Posted September 20, 2006 Why you should never use an extension lead (at anything close to it's rating) when it's coiled Link_Here Making a figure eight will almost certainly (unless we are talking about stupidly long lengths (>100m)) provide much more cooling than having the lead coiled. Magnetic effects of AC cable are pretty minor anyway. Coiling DC cable can produce some nice magnetic effects but unless someone is trying to navigate across your stage with a compass you probably don't care! Link to comment Share on other sites More sharing options...
andy_s Posted September 21, 2006 Share Posted September 21, 2006 Another one for you more experienced lot: I was once told that when using two condenser microphones close to each other (eg a lecturn), you should reverse the phase of one of them. I didn't find it making any difference. Has anyone else heard of this and why was it suggested? Edit: I just realised this is in the lighting forum! Oops. Still, would be interested. good to see the topic nicely diversifying. I can only see two valid reasons for having 2 mics on a lectern (correct spelling - my boss pointed this out to me when I used a "u"). firstly - redundancy in case one breaks, and secondly easthetics: putting a great big mic in the middle might mean the view of the speaker is obscured, (how can you tell they are lieing if you can't see their eyes?) and putting one mic to one side would look unbalanced. I can't see any sonic reason, (unless there are two speakers) but perhaps someone can enlighten us? Link to comment Share on other sites More sharing options...
Andrew C Posted September 21, 2006 Share Posted September 21, 2006 "Aesthetics" aside, if the speaker turns his head to the side you loose level. I know that with training they can turn their body so that they address the audience at the sides across the mic, but some speakers will have none of it! :P I can't say I've noticed phasing issues, but I accept that in theory it could happen. Link to comment Share on other sites More sharing options...
mikienorth Posted September 21, 2006 Share Posted September 21, 2006 Microphones.Well, I'm just a spark, and what some clever bod ib the noise business told me about cross-phasing microphones is:You place two microphones crossing over each other just a tiny bit, and cross phase one of them, and then send them both down one channel? (not sure about the last bit) and effectivley you get a larger area of coverage from two mics behaving as one, instead of two mics covering two areas overlapping, effectivley you get one mic doing a bigger area? Its a black art to me, sound is the work of witchcraft and pixies.... Figure 8 cables.Its all to do with eddy currents IIRC, the same reason all live, neutral and earth conductors must pass through steel in one hole, not three separate ones. Fault currents are always really high, into kA, even if just for a few milliseconds.They also look nice, and uncoil well, and when coiling them into a case, you can always coil another bar loom on top of the feeder multi in a normal manner, just to get the weight heavier than you can comfortably push. It's to do with getting the current to flow in different directions or something, and leaving the cables in a nice tangle behind the racks does the same thing, but coiling straight is bad. That's what I was told by the older and wisers that showed me it... Link to comment Share on other sites More sharing options...
Seano Posted September 21, 2006 Share Posted September 21, 2006 It's to do with getting the current to flow in different directions or something<Sigh> This myth has already been busted, see above. That's what I was told by the older and wisers that showed me it...On this subject at least they were just older. Link to comment Share on other sites More sharing options...
Bean Posted September 21, 2006 Share Posted September 21, 2006 Here's another "myth", are the new DMX dimmers better than the old analogue dimmers? Just throwing this out there. Link to comment Share on other sites More sharing options...
Ynot Posted September 21, 2006 Share Posted September 21, 2006 Here's another "myth", are the new DMX dimmers better than the old analogue dimmers? Just throwing this out there.Ummm... Here's another - Is chalk better than cheese??? Link to comment Share on other sites More sharing options...
Tomo Posted September 21, 2006 Share Posted September 21, 2006 Here's another "myth", are the new DMX dimmers better than the old analogue dimmers? Just throwing this out there.Yes. Less cable to break, and cheaper to replace the control cable when it fails.Note that I'm ignoring everything that happens inside the dimmer. Link to comment Share on other sites More sharing options...
Brian Posted September 21, 2006 Share Posted September 21, 2006 Here's another "myth", are the new DMX dimmers better than the old analogue dimmers?No. More electronics = more points of failure = less reliable. Link to comment Share on other sites More sharing options...
Ekij Posted September 21, 2006 Share Posted September 21, 2006 By 'Old analogue dimmers' are we talking about a variable auto transformer with a wiper that takes the output off any point in the primary? (A bit like a potentiometer but with windings)? If so these are not as reliable as electronics. By nature the wiper rubs on multiple windings. Things with moving parts are prone to failure, the wiper shorts out some coils which causes excessive currents to flow in them exposing them to mechanical stress. I'll take a DMX dimmer over an analogue one any day, better for:1] Power consumption2] Reliability3] Safety (better isolation) Link to comment Share on other sites More sharing options...
Brian Posted September 21, 2006 Share Posted September 21, 2006 By 'Old analogue dimmers' are we talking about a variable auto transformer...Or even salt water dimmers :blink: :D :D Link to comment Share on other sites More sharing options...
bruce Posted September 21, 2006 Share Posted September 21, 2006 Here's another "myth", are the new DMX dimmers better than the old analogue dimmers? Just throwing this out there.Yes. Less cable to break, and cheaper to replace the control cable when it fails.No. More electronics = more points of failure = less reliable. Define "Better". Link to comment Share on other sites More sharing options...
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