some excellent info !
some excellent info !
-this is a bit long, sorry....
My background has covered small components like microphone capsules, these are typically 50p, but require some detailed knowledge to make them work in practice . . . . along with abilities in mechanical engineering to build a body, source the shield and so on.
Looking at the spec. of many £100+ mics - - They are condenser "...with permanently charged fields, etc" . . . this means is they are electrets. Tiny mics which require only a matching amplifier (yes "only" - that's beyond this discussion.) - but what it means is this: they are probably using one of those 50p inserts.
I wonder if any pro's here know for certain where these mic-companies get their bits? For it seems to me that few are manufacturers of delicate parts, so they must get them somewhere and if it's not a dynamic (moving-coil, like a loudspeaker in reverse), then they will be likley as not electrets, which are cheap and have a fabulous freq ability, typically 20Hz - 18kHz and it is their LF ability that makes the manufacturer provide a Bass-cut facility. This is a clue, IMHO.
What I've not found is the original source of the larger (eg 20mm Dia.) electrets which some studio mics boast - presumably they are made by the same co's that make the 10mm Dia capsules - which find themselves in Video-cameras, portable recorders, phones and thousands of other applications. Indeed at that price/performance you'd be a foolish designer not to give one a try.
The interface circuit of course is a different matter, using low-noise amplifiers and surface-mount components, it can fit into a small space and in volume-production will add maybe £1 to the total. Then there is the sleek anodised tube, connector and shield, say £2 the lot.
So, overall we are talking about maybe £5 including the foam-line carboard box.
Whilst I accept these Co's have to make a profit, it doesn't seem right to say that cheap mics are necessary bad mics - although one described above - could be priced maybe £50 and no-one would complain.
However, I did buy one mic for £1 (poundshop), which was about as close to rubbish as I have found. The capsule (moving coil) was loose, so it rattled (not a good start) and the on-off switch was mis-wired and the cable was loose in the tail-end grommet, so that rattlerd on its own. A small attention to detail would have made this at least useful (ie if all else failed). As it is it will provide me with a Good Story ( Reading this far?), and the component parts to make an electret experimental platform. Oddly the shield is real wire mesh with an open-cell foam behind - this is what you'd expect in decently engineered product, but I guess they get the throw-outs from a good mic company and sift through their bins...?
What it come to is this, IMHO
1) the sound - very important naturally, - but note 2,3,
2) handling - it must contribute as little noise as possible.
3) electrical noise, usually caused by poor electronics, but the cable is also a contributor if poorly spec'd. Sometimes you can change the cable and Pro's use XLR because you can stand on them without damage (to the connector!) and they have a decent cable-grip, so it won't fall apart miles from base.
4) this is the convenience of battery-changing, where phantom-power is missing....something to consider that the battery-life is long and easily replaced in the cold.
Now how do we check the "sound" if the listener wasn't present at the Recording? Very difficult which is why many OB's are dubbed with appropriate noise - much easier to control. But you can perform an easy test..... not applicable to recording drums, though.
This won't apply to "shotgun" mics which are directional, unless you know otherwise...
= Take a CD of piano recordings and play it at normal volume in a reasonably bright but damped room. (thus little in the way of echo). Record, using fav mic and the one under test, ideally placed close together, centre. Then replay through the same Hi-Fi. As a casual observer, you should not be able to tell the difference between the two recordings - well, that's some hope, but it should provide a means to "rank" your collection of mics.
Sadly, some prefer "bright", others like smooth . . . etc. so unless it has "resonances" (Ugh!) almost any decent mic should perform well enough.
Of course, "outside" presents other problems - mainly wind (and rain).
One of the shortcomings of electrets is their sound-level ability - they don't like high-level sounds and will distort if used close to percussion (eg drums, cymbals). But then I wonder why there aren't silencing-hoods for this application (audio equiv to Video ND filter), as this would provide some degree of protection against peaks of sound . . . which is what we hear as distortion, any good sound-designer should be able to come up with something that doesn't ruin the freq resp, but this may be the greater picture...
Last edited by vidmanners; 06-24-2011 at 02:33 PM.
a) sometime the use of lav and wireless mics attahed to the talent is a viable alternative to other forms of mic'ing, so long as it doesn't matter if the mic is visible
b) for Voice over work, you can use dynamic mics that do not require phantom power. Long time standards have been the Shure sm7 ( or sm7B) and the Electrovoice RE20. Large diaphram condensor mics are also often used for this purpose. These tend to be more expensive, and long time standard mics are the Neumann U87 and AKG C414. There are other less expensive mics, that can do the job well too.
c) For recording ambiences, a stereo pair of small diaphram condensor mics with cardiod capsules is a good option. Some to mention here are, Shure sm81, AKG C451, Octava MK-012
Having good microphones is very important, but the quality of the mic preamps and the A/D conversion will also greatly affect the results, and your overall sound will only be as good as the weakest link in the chain.
Last edited by rocksure; 03-11-2012 at 08:29 AM.
Microphones similarly play an crucial roll in the sound quality of audio recording. Using a cheap microphone on even the most advanced audio recorders will result in terrible sound. Thanks for the wonderful explanation, it will changed my thoughts of using high ranged microphones..
We must not forget that the Law of Diminishing Returns also applies - a mic costing £30 will give reasonable sound, one costing £300 is not 10x better, although a pro may believe the extra cost is worthwhile. However a £3k mic should be some improvement . . . but only slightly better . . . and in many instances the original is a distortion - so what does it matter if a little more is added by the mic? (I exclude noise/ clipping, of course).
An earlier Poster got close to this as well - namely that a poor mic close to the source will almost always sound better than a very expensive mic at a considerable distance.
Un-named £20 SG mic (with battery) from China used on Sony CX740E. Mic mounted on a hot shoe bracket (£7) screwed to the tripod receptacle as the cam has hot shoe only for Sony accessories (Sony SG for the cam is too pricey for me)!
I listened through headphones and was really put off by the amount of background noise. I assumed that it was because I was listening for it. So I listened again through my mid range PC speakers, expecting no to hear the noise, but it was surprisingly prominent. It's a shame beacsue without the background hiss it actally seems to do a reasonable job of capturing the dynamics and tone of the Mayor's voice. As Paulears says the hiss seems to be a bit lower in frequency than normal hiss (it's certainly not white noise). If anything, I fear this would be more difficult to reduce in post because it is in the same frequencies as the voice.
I'd suggest trying a cheap lav for such interviews (eg ATR 2550). Proximity is everything.
Thanks, Tim! Could it be the camera noise as the mic was mounted on the camera (through the bracket that I used).