mshilarious
Banned
Well yeah, I prefer to do HF compensation with a filter off the capsule FET, usually a shelving filter to limit the HF load. It can be done on the output, but that requires component values ~50x as large, which is a bit more expensive to use the nicer parts.
In other news, how do you do a large diaphragm mic at -43dBV/Pa while consuming 6.6mA? I mean c'mon, there are trafo-out mics at less than 2mA with sensitivity close to that. I don't get that trend in the low end. High end, fine, drink 10mA if you like, but a lot of lowenders are gonna be using low-end USB & Firewire interfaces, and some of those struggle with 7mA.
That also leaves only 25V at the mic, so you figure it has to have a step-up circuit.
This gets back to my earlier comment on the SM27: similar frequency response, tighter cardioid pattern, lower noise, higher sensitivity, high quality fit & finish, looks to be a smaller form factor (no reason to pretend to use a case large enough for transformer & tube when there aren't any), *slightly* less power consumption (although 5.4mA doesn't win the energy star award either). That for $279, is that less than the 2003A + mod?
OK, time for random poster to line up and say "hey msh, specs just don't matter, man, it's the *sound*, man, like when Gene Krupa goes bip bap bip bip bip bap bap bow!"
So I will show you how they do. First, if your interface really isn't up to snuff phantom power-wise, it means even lower voltage to the mic. How does the mic handle that? A good step-up circuit will be able to compensate to some degree. A simpler one, say a basic doubler, will cause the capsule polarization voltage to drop. At a minimum, that's a loss of sensitivity and poorer signal-to-noise. So my first question about the guts (this is true for any bit of kit) is how robust is the power supply?
Back to sensitivity--what's the beef there? OK, as I said, the MXL spends 317mW to generate a rather low sensitivity of -43dBV/Pa. Why does that matter, gain is cheap right? Yes, but noise is always waiting to bite you in the butt. -43dBV/Pa combined with 11dBA yields a noise floor at -126dBV-A (-124dBu-A). If you want to avoid accumulating noise along your chain, you need to make sure that your preamp noise is sufficiently quieter than that. Many are, but some aren't. Further, let's talk about noise spectrum as Mr. Joly mentioned. LDCs tend to be very 1/f (pink); preamps are white. So even if your preamp measures -127dBu-A, above 10kHz it will be the dominant noise source. You might never notice if all you record is vocals, but try it on something truly quiet and you might wonder why 11dBA is so noisy . . . you never had that problem with any of your other condenser mics?
Back to our cheap interface problem, those are often not the quietest. So we have a potential system where lack of proper phantom power and a kinda noisy preamp could result in a combo that significantly degrades the noise performance of the system, and when you're done you're back at the effective noise level of the old 2003 mic (16dBA) or worse, but you're using more than twice the power, and you have to use at least 7dB more gain to hit the same level.
Pros don't worry about that, they would say use a better preamp. But at the $170 price level, I think it helps to assume that customers are using crap . . . that is something I learned the hard way
In other news, how do you do a large diaphragm mic at -43dBV/Pa while consuming 6.6mA? I mean c'mon, there are trafo-out mics at less than 2mA with sensitivity close to that. I don't get that trend in the low end. High end, fine, drink 10mA if you like, but a lot of lowenders are gonna be using low-end USB & Firewire interfaces, and some of those struggle with 7mA.
That also leaves only 25V at the mic, so you figure it has to have a step-up circuit.
This gets back to my earlier comment on the SM27: similar frequency response, tighter cardioid pattern, lower noise, higher sensitivity, high quality fit & finish, looks to be a smaller form factor (no reason to pretend to use a case large enough for transformer & tube when there aren't any), *slightly* less power consumption (although 5.4mA doesn't win the energy star award either). That for $279, is that less than the 2003A + mod?
OK, time for random poster to line up and say "hey msh, specs just don't matter, man, it's the *sound*, man, like when Gene Krupa goes bip bap bip bip bip bap bap bow!"
So I will show you how they do. First, if your interface really isn't up to snuff phantom power-wise, it means even lower voltage to the mic. How does the mic handle that? A good step-up circuit will be able to compensate to some degree. A simpler one, say a basic doubler, will cause the capsule polarization voltage to drop. At a minimum, that's a loss of sensitivity and poorer signal-to-noise. So my first question about the guts (this is true for any bit of kit) is how robust is the power supply?
Back to sensitivity--what's the beef there? OK, as I said, the MXL spends 317mW to generate a rather low sensitivity of -43dBV/Pa. Why does that matter, gain is cheap right? Yes, but noise is always waiting to bite you in the butt. -43dBV/Pa combined with 11dBA yields a noise floor at -126dBV-A (-124dBu-A). If you want to avoid accumulating noise along your chain, you need to make sure that your preamp noise is sufficiently quieter than that. Many are, but some aren't. Further, let's talk about noise spectrum as Mr. Joly mentioned. LDCs tend to be very 1/f (pink); preamps are white. So even if your preamp measures -127dBu-A, above 10kHz it will be the dominant noise source. You might never notice if all you record is vocals, but try it on something truly quiet and you might wonder why 11dBA is so noisy . . . you never had that problem with any of your other condenser mics?
Back to our cheap interface problem, those are often not the quietest. So we have a potential system where lack of proper phantom power and a kinda noisy preamp could result in a combo that significantly degrades the noise performance of the system, and when you're done you're back at the effective noise level of the old 2003 mic (16dBA) or worse, but you're using more than twice the power, and you have to use at least 7dB more gain to hit the same level.
Pros don't worry about that, they would say use a better preamp. But at the $170 price level, I think it helps to assume that customers are using crap . . . that is something I learned the hard way
This is because every circuit is a compromise, and the specs tell you where the choices were made.
