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Why is the FR2-LE field recorder only 12 volts, when phantom power requires 48 volts?
I’ve used this recorder for years now, but I always found myself having to turn it almost all the way up to get the levels high enough for recording average dialogue, with a boom mic.
I wondered if this was normal, since I used the Zoom F8 and didn’t have to turn it up as high, while in film school. I asked someone else about the FR2-LE and he took a look at mine and said that it says right on it that it only has the power of 12 volts, where as I need 48 for phantom power. Is that true though, that a company like Fostex would put out a field recorder, with not enough volts to power phantom power though? Or am I wrong?
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55 Replies
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Few (if any?) modern microphones require the full 48V of phantom power.
Many (most?) will operate to their full capabilities on 24V or even 12V.
It uses a considerable amount of battery power to create 48V from the much lower internal voltage that modern gear operates with. And considering the dwindling number of microphones that need the full 48V, we are entering an era where 48V will be a relic of the past.To be sure, there are some older and/or boutique microphones that still want the full 48V. You should certainly experiment with your gear “offline” to see how phantom voltage affects your different microphones.
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Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder. -
Hello Ryan and welcome to the Cow Audio Forum.
What instructor at what school told you that?
This link indicates that the unit will run on a 12 volt supply.
https://www.wildlife-sound.org/resources/equipment/2-uncategorised/48-fostex-fr2leFor some years now, units that are powered by 12-16 VDC have the ability to supply 48 V DC for Phantom Power. Internal circuits use more current to boost the voltage.
Phantom Power, or any power, for that matter, is expressed in some number of watts or milliwatts.
The simple formula P = I x E, where P = power. I = current and E = voltage explains it nicely.
An externally polarized mic requires Phantom Power. That power is a combination of voltage and current. If you have less voltage, you need more current. If you have less current, you need more voltage. Otherwise you starve the mic and that usually results in lower sensitivity, higher noise and more distortion.
The spec of the unit says it supplies 48 V DC. The real question is, how much current? Enough to power the condenser mic you want to use!
Some condenser mics require a little current, some more. Phantom power can be set at 12, 16, 24 or 48 V DC. But, again, how hungry is your mic and how much current does the Phantom Power supply?
You instructor was ill-informed.
Any questions?
Regards,
Ty Ford
Cow Audio Forum LeaderWant better production audio?: Ty Ford\’s Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford\’s Blog -
Oh okay thanks. When you say 48V will be a thing of the past do you mean most newer microphones will not need it then?
Also, what do you mean by ‘offline’ in this context?
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Oh well I took a course at the Recording Arts Institute of Saskatoon, and they said it’s gotta be 48 volts and that if I am having low quality, than that’s likely my problem if the pre-amplification is not going high enough.
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Oh well I took a course at the Recording Arts Institute of Saskatoon, and they said it’s gotta be 48 volts and that if I am having low quality, than that’s likely my problem if the pre-amplification is not going high enough.
Not quite correct. The standard, for years, has been 48 V DC, but not all condenser mics require 48 V DC. Some work with 24, 16 and even 12 V DC.
Per my previous comment. Even if it is 48 V DC, if the supply doesn’t have enough current, the mic is starved and won’t sound good.
You may just have a mic with a lot of noise. What’s the make and model of you mic?
Regards,
Ty Ford
Cow Audio Forum LeaderWant better production audio?: Ty Ford\’s Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford\’s Blog -
Oh okay thanks. I have the Rode NTG-3 and the Audio-Technica 4053b. It seems to me that the 4053b, needs more, if that’s right?
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It’s entirely possible that the NTG 3 has a hotter output than the 4053. That has nothing to do with phantom voltage. Compare the specs of both mics and you’ll see the output level differences. If a mic is designed to only run on 48vp then it will be +/= 4 volts or 44-52vp.
\”I push the RECORD button and hope for the best\”
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Hello Ryan,
The sensitivity figure of microphone tells you what you need to know. Below notice the AT is -34 whole the NTG-3 is -30 or -31. The 34 is s larger number, but it’s a minus 34, so it’s not as great as a -30. The -30 mic will be a little more sensitive and require less preamp gain.
AT4053B: OPEN CIRCUIT SENSITIVITY -34 dB (19.9 mV) re 1V at 1 Pa
NTG-3: -30.0dB re 1 Volt/Pascal (31.60mV @ 94 dB SPL) +/- 2 dB @ 1kH
Regards,
Ty Ford
Cow Audio Forum LeaderWant better production audio?: Ty Ford\’s Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford\’s Blog -
Okay thanks, my ears were telling me that the 4053b needs more gain so I guess I was right, then it looks like. However, does this mean that the Zoom F8 is a better field recorder cause you don’t have to turn the pre-amps up as high to power the mics, and therefore less gain and less noise floor cause of more power?
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Hello Ryan, you don’t need ears to discover mic sensitivity. Just plug in both mics and set the input levels equally and watch the meters when you hold the mics together and speak into them. Or, as shown earlier, read the specs.
Preamps and mixers are all different. If preamp A is quieter than preamp B, you can turn it up more. At some point the noise of the mic comes into play. They call that selfnoise. Different mics have different selfnoise figures. The best options are sensitive mics with low selfnoise going into preamps with low noise.
Regards,
Ty Ford
Cow Audio Forum LeaderWant better production audio?: Ty Ford\’s Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford\’s Blog
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