Using Low-cost Hand-held Recorders With the Amplified Wildtronics Parabolic Microphones
In this Article, we will discuss the potential reasons for using a low-cost hand-held recorder, how high quality results are possible, the required specifications that need to be met, test methodology for approving a recorder, test results of a Tascam DR05, use with the Wildtronics Amplified Parabolic Microphones, and how the results compare to much more expensive equipment. See our other Articles for more background information that may also help you understand this Article.
Why Use a Low-cost Recorder
Normally, a low-cost recorder would not be considered for quality results with low level audio conditions. Cost is one obvious reason to think otherwise, with tempting prices in the $100 range compared to higher priced recorders offering full performance, but at a price of over $1000. The low-cost units have advantages: They are very small, light, and have better battery life by comparison. They use small 3.5mm connectors instead of the usual bulky XLR style. If you drop one in a mud puddle, you won't feel so bad, and purchasing a spare is much more palatable. You can also dedicate the recorder to a single purpose such as a parabolic microphone and free up your other equipment. Most are easy to use, and once setup, turn on in seconds, with all setup intact, and are ready to record with just a quick one-button press. They usually include a LCD level meter to ballpark your gain settings, and even a little speaker to run through your recordings. If they can offer suitable performance, they would make a perfect companion recorder for an Amplified Wildtronics Microphone.
What is Wrong With Low-cost Recorders
The basic problem with these low-cost recorders is that they have poor input noise, from -100dBA EIN at the lowest cost end to -120dBA EIN for the medium priced units. EIN is the equivalent input noise specification. We prefer to see <-125dBA EIN for use with high level microphones in low level situations, and <-120dBA for use with the extra high outputs of the Wildtronics Parabolic Microphones. The input noise will cause the familiar hissing sound of a kitchen faucet running. The units are improving, and are even adequate for higher level use or use with higher noise mics, but not quite good enough yet for low level use such as recording nature sounds, birds, or surveillance. Of course, the internal mics are not intended for low level use at all, but are great for notes and narration. Many units do not offer XLR inputs and phantom power either. They also lack many of the outward features that users of high priced larger units may appreciate, but these features are not really necessary for a high quality recording, so will not be discussed further here.
What is Needed to Make a Low-cost Recorder Perform
A pre-amp with a suitably lower EIN, placed between the microphone and the recorder input, can eliminate the input noise problem. The recorder gain is decreased to near minimum, often using the line input, and all gain is provided by the external low-noise pre-amp. Unfortunately, good pre-amps are not cheap either. The recorder will still require good SNR on its output stage and A/D converter as well. This specification is often referred to as dynamic range, and many units do not specify it. Many very high priced units also do not completely specify output SNR. 24-bit audio A/D converters are capable of 120dBA dynamic range, but no manufacturers are offering anything at this time over 114dBA, and some of the favored high cost units are only 103dBA. In addition to the A/D, the output amp often adds noise to the system too, high priced units are typically only about -100dBA, but the exact value is in-determinant from the specifications offered. With an output noise of -100dBA, combined with an A/D noise from103 to 114dBA, the total dynamic range will be from about 98 to 100dBA. So, to summarize, dynamic range is in the upper 90s for many high priced recorders in use today.
The question is, how good does dynamic range have to be for a high quality recording? The answer depends on the SPL level of your subjects and your microphone noise floor. Your SNR requirement can be easily calculated: SNR = (SPL – MICselfnoise + 6dB + Headroom). For example: The loudest natural outdoor SPL, where mic noise would ever be noticed, is about 80dB. The best microphones are about 10dBA, and a headroom of 20dB is ample for most anything; so a dynamic range of 96dBA is the requirement. With 10dB of headroom till clipping, you could even get by with 86dBA for dynamic range under the same conditions. More than that may be needed for some applications, such as orchestra recordings, where levels go from quiet to very loud. The high priced units just make this specification, and some of the low-cost recorders have dynamic range in the 90s as well when it is specified. This is good news, meaning the noise problems are confined to the input amplifiers, and therefore are correctable by good external pre-amps!
THD is also of concern, with high cost units offering .005% to .05%, and low-cost recorders typically achieving at least .05% as well – not the weak point again. Sampling rates are up to 24bit @ 96KHz just as in high cost units. Limiters, rumble filters, level meters, headphone outputs, and more are all there in both high and low cost units alike, although not as handily accessed in the low cost group. All critical issues have been discussed, and the conclusion is: If suitable pre-amps are available that offer the correct phantom power and connectors for the microphone, the low-cost recorder can achieve results comparable to the best recorders on the market.
The Tascam DR05
We selected the Tascam DR05 as a potentially suitable low-cost recorder, and performed some critical tests on it. The DR05 is small, only 4oz, with only 3.5mm connectors, has a nice readable display which works in sunlight or total darkness, and is only about $100. You can read all about it on Tascam's website, our purpose is only to confirm critical specifications, and suitability for use with our products. The EIN specification of -109dBA reveals it will not be good enough for quality low level recording on its own. No phantom power is available anyway for use with high quality microphones. The dynamic range is specified at 92dBA minimum, without further information.
Testing verified the EIN specification to be -108dBA. The dynamic range, with the gain set to the lowest position as it would be used with a preamp, was an excellent 98dBA. We also exposed it down to -10 degrees F, humid environments while cold to induce condensation, and higher temperatures, and NO problems were found. The Tascam DR05 met all the requirements of an ideal low-cost recorder for use with the Wildtronics Amplified Microphones. The only issue was that the VU display was a bit harder to read compared to an LED type display on a more expensive unit, but since record levels are set well below clipping anyway this was not really problem.
Wildtronics Combined With a Tascam DR05
Wildtronics offers several models of high quality parabolic microphones including, units with stereo, amplified versions, and amplified versions with a stereo mixer. These amplified versions have built-in low-noise/distortion, variable-gain amplifiers that can connect to headphones, DSLR cameras, video cameras, and RECORDERS. The output jacks are 3.5mm. EIN is conservatively specified at -126dBA, and output noise is -115dBA. The pre-amps add no noticeable noise to the system. Phantom power is not needed and is built-in to the Wildtronics microphone units. You can see what a perfect match this is for a recorder like the Tascam DR05.
When the Amplified Wildtronics Microphone output is connected to the line input of the Tascam DR05 with a 3.5mm cable, with the Tascam gain set to minimum, and the Wildtronics gain knob is used to quickly set the record level to around -15dB VU; results are excellent. You get a super low-noise high-output mic, with a -126dBA EIN preamp, and the full 98dBA dynamic range out of the recorder. Recordings are indistinguishable from recordings made with the best equipment available: Samples can be heard below and more will be added in the future. This is no surprise and just as the preceding theory predicted. This report reveals the amazing potential of these low-cost recorders when combined with the right equipment. Wildtronics now offers an optional Mini Accessory Bar Kit that allows you to mount a small hand-held recorder right on the handle of their Parabolic Microphones. This offers rapid deployment, is lightweight, totally cord-free, is easy to use with one hand holding the microphone, and makes a super run and gun recording system.
The Tascam DR05 or equivalent combined with the Wildtronics Amplified Parabolic Microphone is very cost effective, makes getting started in outdoor recording easier than ever before, and will produce superior results. The Wildtronics Parabolic Microphones, with their Patent Pending enhancements, can improve SNR in real world conditions by about 20dB compared to other parabolic systems. The Tascam DR05 does not contribute any noticeable noise to your recordings when used as described above.
It sounds too good to be true, but with this combo, you can actually have the best performance, and the lowest cost too!!!
Buy your Amplified Wildtronics Parabolic Microphone Now: Wildtronics Amplified Mono Parabolic Microphone, or the Wildtronics Mono-Stereo Parabolic Microphone.