Re: Bargain condenser mic questions
Posted: Fri Mar 13, 2015 6:24 am
Reverse Entropy wrote:newholland wrote:i will say absolutely, that given a stable, constant phantom voltage, and not super high input impedance input load, that a LOT of mics that i thought were meh turned out to be WAY better than i thought they were for years, and a lot of my cheapie performers got way better by leaps and bounds when i plugged them into single power supply devices with lower loads. less expensive interfaces and mixers shoot for the 'average'.. and to my ears, it's pretty far off with a 3-5kOhm input- where dropping it to 500 Ohms makes a MONGO difference over the entire spectrum to my ears. used to be (pre-mackie days) that your average was probably 3-500, but for whatever reason the VLZ pushed it higher, and things got crispy..maybe made sense in the analog era... but gah.. it's harsh for digital.
Oof. I'm sloppy, I wasn't thinking about impedance matching yet.
Question, and I'm not being a picky-ass I just want to clarify so I understand you properly...
Lower resistance (in AC, impedance) electrically loads a circuit more heavily (high current, low voltage drop) and high impedance the opposite (low current through, high voltage shows across the inputs). Did you reverse this when you typed that, or am I missing something ? [it's been a long while since my power circuits courses...]
Looking at my various few options in preamps / mixers for an upcoming mobile project, the "low" impedance inputs are all in the 3k to 5k ohm range you mention. Looks like I'm setting myself up to fail unless I find a lower impedance preamp for the mikes.
Perhaps a Presonus Blue Tube DP ? Any other suggestions ? From the discussions here I suspect I'll end up using a pair of M179s or KSM27s.
i can't necessarily speak to the electrical aspects-- but i do know that when you drop the impedance of a mic input circuit, you alter the frequency response. if you're shooting for maximum frequency response, the rule of thumb is something like 10:1-- so a 150 ohm mic should see 1500 ohms at the pre. but seriously.. who records every source 100% full frequency? oh yeah.. nobody.
when you drop input impedance, the mic'll focus more on midrange frequencies. things loosen up, you lose a little top, and a little bottom, but things can get pretty technicolor in the PERTINENT frequencies for most music.
this isn't to say that one can't make good recordings with higher impedance mic pres-- only to say that some of the things that make modern recordings sound dry and hifi is this fact, and it's one of the reason i think that a lotta people think mics sound bland and whitewashed comparatively. i'm certainly no believer in the DC to light frequency response.. it's just not necessary, and i think it sounds pretty bland too. but i've sure recorded a lot through mackies and done okay.. i'm just happier with lower input impedance preamps and have a couple. i still record drums through high z inputs because they give what they've got over a broad range-- and i tend to not close mic them- so i'm looking for an overall picture of the kit with less mics. i'll often record guitars high z, because they're not super fussy, but if it's one track at a time.. i'll use lower. bass? depends.. but either works well- depends on the tone. vocals? i usually go for a lower value, absolutely. other instruments too-- but by and large, i prefer going in at 3-500 ohms.. and again... totally depends on the mic and sound.
there's not really rules-- but i really more wanted to make mention of the fact that some of these less pricy mics can sound really good and it isn't just the mic that bungs things up to sound meh! they ain't all fantastic.. but some of them are really really good for what you pay for them compared to what you'd get 15 years ago for 10x the price.
wrt what pre? well.. a lotta guys sorta start their missions with the art pro mpa2. i've had no particular love for any presonus gear, tbh-- and i do know the ART unit HAS adjustable z. so does the focusrite twintrak pro (i have one- works fine, but nuttin' fancy). but my focusrite interface ALSO has low z input (drops to 300ohm) on one channel. not well advertised.. but it does. for on the cheap--either of those two units'll give you some flexibility though, and at least let you see what happens-- and seriously-- just listening to what happens will blow your mind. it's not always subtle.