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How quiet is the Hi-MD mic preamp? Raimund Sprecht measured the Input Noise of the Hi-MD preamps at -124 dBu (A weighted). All Hi-MD models have the same pre circuit. The Hi-MD mic pre is significantly quieter than older MD recorders (one comparison). The majority of the mic pres in the newer "pocket flash" recorders are also noiser. (See 5th column, "Measured Mic Input Noise" on the RecorderList.) The Hi-MD pre is not as quiet as the top of the line recorders such as the Sound Devices units, the Fostex FR2-LE and the Tascam HD-P2. It seems to be safe to regard the Rolls/HiMD mic preamp combo as quiet enough to use with a mic with an effective EIN of -110 or lower. The effective noise value for any mic can be computed by using the manufacturers' Self-Noise and Sensitivty ratings in Rane Notes 148 Table 3. One can only use these numbers as a rough guide however, The Sennhesier MKH 40, for example, with a self-noise rating of 12dB(A) and a sensitivity rating of 25mV/Pa computes on the Rane Table to -110dBu. In order for the mic pre to not contribute noise, its noise level needs to 7-10 dB(A) lower, For the MKH-40, a mic pre with -117 dBu to -120 dBu would be required. Comparison tests I have done suggest that the self-noise from the Rolls/HiMD mic pre is barely detectable with that of the MKH 40 while the numbers suggest the Hi-MD pre would be entirely inaudible. Sony's PCM-D50 flash recorder has been tested to be slightly quieter (-126dBu [Aweighted]) and the more recent Sony PCM-M10 has tested as slightly noisier (-122dBu [Aweighted]). The preamp in the Hi-MD recorders provides a whopping 75dB of gain-- about 5 dB more than a Sound Devices 722 recorder. The input stage of the Hi-MD recorders is based on the Asahi Kasei AK5356 20 bit ADC mic pre chip. AK5356 Spec Sheet and AK5356 discussion. If you are considering a recorder to use with mics that have extremely low self-noise for recording ambience in quiet locations, the noise plots for the Rode NT1-A mic on this excellent PDF by Raimund Specht show the critical relationship between mic sef-noise and recorder mic preamp noise. My thanks to Raimund Sprecht, Dan Dugan, Klas Stranberg, Curt Olson, Gerry White, Eric Benjamin and many other recordists in compiling this information and confirming results in the field.

Hi-MD & low noise mics

I'm impresssed by the capabilities of this $600 field recording kit even for demanding subjects like ambience in quiet locations. It incorporates a pair of AT-3032 mics, a Rolls PB244 portable phantom power supply, a 3.5mm to XLR adapter cable, Sony MDR-V600 headphones, 2- battery sleds and a Sony HiMD Recorder. The HiMD's have surprisingly low noise performance and exceptional gain (75dB). The low-cost of the recorder allows one to unvest in good, low-noise mics having a huge impact on overall recording quality. For mounting the AT3203's, I recommend Curt Olson's DIY stereo mic arrays. There are several tests in my Gallery comparing the noise perofrmance of HiMD to pro and consumer recorders. Here's a comparison between the Sound Devices 722, M-Audio's MicroTrack 24/96 and NH900 Hi-MD <4mb QuickTime movie> -Rob Danielson

   

Hi-MD Forum

 

Art/Rolls-> Hi-MD Adapter Cable

 

DIY Battery Sleds

 

Dan Dugan's AT-3032 recordings Josuha Tree Plams, Frogs, Rain & Jet ; Indian Cove Sunrise

 

Curt Olson's urban ambence with AT-3032's followed by Shure WL183's. Curt's DIY Arrays.

 

Hi-MD Tips

 

Smith Victor RS 75 Raven Light Stand -very portable

 

More Recorder & Mic tests

 

Wash MIt Zeppelin

 

 

 

 

 
QuickTime Player VideoLan MediaPlayer      

Audio Technica AT-3032.

Eric Benjamin'surprising bench test results.

Eric's comparison test with Schoeps MK_2 on left and AT-3032 on the right which was posted on the micbuilders list.

Any 48 volt phantom-powered mics can be used with the Rolls and the HiMD recorder. The AT-3032, with its low self-noise, high output and versatile omni-directional pattern, is quite a bargain. Other quality mics in the lower cost, very low noise category include the Rode NT1-A, NT2-A and Rode NT2000.

 

 

 

"Which Mic is Right?" by Michael Cooper walks through understanding microphone terminology. His minimum self noise figures are probably as little too high for quiet location field recoding, but its a very worthwhile read for anyone thinking of investing in microphones.

 

Download EXCEL spreadsheet with mic Self- Noise and Sensitivty specs.

 

 

 

Mic Self-Noise and Sensitivty specs as HTML (may not be as up to date).