Powerful, Portable Microphone Preamp - Shure FP23
Written: Dec 02 '07 (Updated Dec 02 '07)
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Product Rating:
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Pros: Superb build quality throughout, powerful gain, clean, noise-free audio output, battery operation
Cons: 1 Channel only, heavy compared to other portable units, no 1/4" or 1/8" outputs
The Bottom Line: If you're looking for a rugged, single channel microphone preamplifier that's fully portable...you found it.
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| silverstreak9's Full Review: Shure Fp23 Portable Battery Powered Microphone Pre... |
╔▓░ OVERVIEW ░▓╗
This review is relevant if you are using professional grade microphones and want to record into a Line Input, like a computer or digital audio recorder.
The Shure FP23 Portable Battery Powered Microphone Preamplifier is pro grade equipment and priced accordingly. (Around $400) It can be particularly useful for producing very clean audio in field situations where the recordist wants to capture the natural environment. Fully portable, it runs off 2 AA batteries and can provide +12/+48 volts of "Phantom Power" to microphones that require it.
There is a SINGLE XLR input and XLR output. The FP23 is NOT a mixer that combines several audio sources into one output. The Output is not switchable. It is Line Out only.
If your device only has MIC IN inputs, the FP23 isn't for you. Some inexpensive microphones that use 1.5 - 9 volt power will not be enhanced by the FP23, they might be destroyed by it.
The purpose of the Shure FP23 is to boost the signal of low-impedance microphones so they can be used in recorders or computers that have line level inputs. The Shure FP23 Preamp does this without introducing noise or "hiss" into the signal.
╔▓░ FIRST LOOK AND FEATURES ░▓╗
We'll just say it right up front. The Shure FP23 Portable Battery Powered Microphone Preamplifier is going to outlast just about every piece of computer or audio equipment we own.
It's built in a rugged extruded aluminum case painted black. It's battery compartment is military grade and a rubber 'O' ring ensures it remains waterproof. There are two very small "handles" on the front of the case that can be used to attach velcro strips to secure cables or attach the FP23 to straps, belts or gear bags.
DIMENSIONS
One of the most appealing features of this preamplifier is its size and portability. It's meant for the field. Whether it will be used by journalists to record voice tracks directly to a computer or by naturalists to get a clean, clear signal from a parabolic microphone setup, the FP23 comes in a package that's small enough -- and tough enough -- to pack along.
43mm(H) x 94mm(W) x 140mm(D)
1.7" x 3.7" x 5.5"
Weight: 0.56 kg - 1.24 lbs.
KEY FEATURES
• 0 to 66 dB gain, adjustable in 11 steps with rotary switch
• High Dynamic Range
• High Audio Bandwidth - 20Hz to 50kHz (according to Shure)
• Very LOW noise - clean, clear audio
• Excellent protection from RF interference
• Low-Cut Filter 80Hz or 160Hz selectable (wind noise etc.)
• Limiter with 5 millisecond attack time, 100 ms release
• 1 Balanced XLR input (2k ohms)
• 1 Balanced/Unbalanced Output (130 ohms)
• Selectable 0, 12, 48 volt Phantom Power for Condenser Mics
The Shure website provides lots of data on its FP23 and audiophiles may enjoy reading through it. There is a User Guide available online in PDF format that contains most of the technical specifications.
http://www.shure.com/ProAudio/Products/MixersAndDSP/us_pro_fp23_en_ug
PHYSICAL LAYOUT
The Shure FP23 Portable Battery Powered Microphone Preamplifier is well designed for its purpose. We like how almost all of the controls are on the front panel, along with the limiter light that warns you when you are coming close to peaks or actually invoking the limiter by either showing yellow or red in the single L-E-D.
The one switch that isn't on the front panel is exactly where it should be -- on the back panel. The switch for Phantom Power selection is right between MIC IN and LINE OUT so you can double check it before a microphone is plugged into the unit.
Used on a desktop, it's very easy to select the amount of gain you want to apply as you monitor the results. There is no headphone plug on the preamplifier, you will monitor the levels in your computer or recorder.
Similarly, the FP23 can be attached to a camera tripod so the cables extend downward and all of your controls are at the top of the unit, facing you.
The 11-step gain switch is nicely sized and gives you solid tactile feedback. If left in a gear bag, the selector won't easily be nudged out of the position you set for the correct amount of gain.
Similarly, the slide switches for the Limiter, Low Cut and Phantom Power are all slightly recessed and require a solid "click" to select and engage.
There is a single L-E-D for Power that notifies you when you are switched ON so you don't drain the batteries. Shure estimates that the FP23 will run for 24 hours on 2 fresh AA batteries. That estimation is based on NOT using the FP23 to supply Phantom Power and your performance will vary depending on how much power you are using and your make/model of microphones.
The XLR connectors for MIC IN (Female) and LINE OUT (Male) are rock solid as well.
╔▓░ PERFORMANCE ░▓╗
The Shure FP23 Portable Battery Powered Microphone Preamplifier is everything it promises. We are very pleased with the audio signals we get from it.
There is one area where this preamplifier really excels: Low Noise. We can adjust our gain upwards and expect none of the hiss we hear from cheaper preamps that may be lurking inside digital audio recorders. By running microphones through the preamplifier, we can be assured of a very responsive, rich and noise-free recording.
Shure rates this preamplifier's equivalent Input Noise at -128 dBV.
When making a recording directly from a dynamic microphone to a computer, we find it pleasing to turn the gain in the software recording program down and let the FP23 do its job. Even then, we find a 42 dB gain applied to the microphone signal is as much as we need.
One experience when using a computer to record at 96 kHz is that the computer itself has to be capable of writing the information to hard disk. We were experiencing sudden drop-out caused because the computer processor/memory could not keep up with the analog data coming into our Line Input on a Mac G4 laptop with a PowerPC processor. Shutting down other programs and freeing up memory helped. Still, something to keep in mind when recording at higher sampling rates and bit depths.
The low-cut (high pass) filters work well to eliminate moderate wind noise but obviously, they are not a substitute for a good windscreen or "Dead Cat." (A large furry windscreen found particularly on performance shotgun microphones that, well, resembles a grey cat!)
The FP23 has a very good Limiter with fast attack times that can protect against loud noises suddenly over-modulating a recording. We aim to record at peaks of -12 or -6 dB in order to avoid that in most circumstances. But it's there and it works well.
Basically, you give up signal to noise levels when you don't record at the highest gain. Limiters allow you to push that a little bit, getting more signal but invoking the limiter more often.
╔▓░ CONCLUSION ░▓╗
We haven't used the Shure FP23 Portable Battery Powered Microphone Preamplifier in a nature recording situation, but if we find the right microphone, it's no doubt up to the task.
The avalanche of technical information out there overpowers most of us who just want a clean, clear audio signal. In the end, all of that technical data gives way to the listening experience.
Our experience with this microphone preamp has been excellent. We are very satisfied with it for our own purposes.
We are also comfortable in recommending the FP23 on the basis of its build quality. So often, we are disappointed when a product that holds so much promise comes wrapped in flimsy plastic.
The Shure FP23 is a rugged, reliable unit that contains the essentials needed for making excellent recordings. It can allow users of inexpensive digital audio recorders with noisy microphone inputs the option of using a cleaner Line Input to obtain a better recording.
Having said that, if you want to use an external microphone with a digital audio recorder, you would be well-advised to purchase one that already contained good, low-noise preamplifiers in the recorder.
While certainly not cheap, the FP23 also offers the phantom power needed for some condenser microphones and can therefore provide "dual use" economy.
╔▓░ APPENDIX ░▓╗
With all of the above discussion of Line Inputs and Mic Inputs, I thought a passage buried in Shure's "Frequently Asked Questions" might be appropriately placed here.
This is an explanation of the difference between Mic Levels and Line Levels.
"Mic-level or microphone-level signal is the amount of voltage that comes out of a microphone when someone speaks into it - just a few ten-thousandths of a volt. (Of course, this voltage varies somewhat in response to changes in speaking volume and source-to-mic distance.)
A line-level signal is approximately one volt, or about 10,000 times as strong as a mic-level signal, so the two do not ordinarily use the same input.
Connecting a microphone to a line-level input will result in almost no sound at all, because the signal is so faint that the line input cannot hear it.
Connecting a line-level source (such as a CD player) to a mic-level input will cause the sound to be loud and distorted because the line signal is much stronger than what the mic input will accept.
Microphone level is usually specified between -60 and -40 dBu. Line level is considered to be +4 dBu"
Recommended:
Yes
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silverstreak9
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Location: Atlanta, GA
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