A flagship product coming at an odd time in MiniDisc's lifetime, the MZ-RH1 delivers all you could really want of a minidisc recorder, and the noise performance measures very similar to the NH700, so it will not significantly compromise the noise performance of low noise mics like the Sennheiser MKH30/40/50. Roger Boughton recently picked one of these up as a portable standby recorder, and kindly lent it to me to play with, so I put it through its paces and repeated some of the tests I performed on my own HiMD recorder, a Sony NH-700
Sony have addressed the operational problems that made the first-generation HiMD recorders a pain to use in the field, and the RH1 sensibly remembers the recording mode you last used - which will be manual level control for wildife sound recordists. Previous models defaulted to AGC and every machine start involved a seven-step run through the menu system.
The operational controls are on the short edge of the RH1 rather than above the disc door, and the main control is on the right-hand side of this edge. Switching into record takes a little practice but it possible, even using just one hand, and the OLED display is visible in the dark and in daylight.
Metering is performed by a virtual 2 x 10-element bargraph with peak and mean display. Sony unhelpfully don't tell us what the bars mean, apart from a vague -12dB mark in the mid-point. I measured this and the steps are
The machine has a good tactile feel with a metal case. In the field I tend to keep the minidisc recorder in a shirt pocket which would be inadvisable with this - it will fall out if you bend down and it would impact on the main control!
As well as sorting out the ergonomics, Sony have also made the transport quieter when writing to the disc. With the first generation HiMD recorders, the mechanical noise every few seconds writing to the disc could be an annoyance in low noise environments, meaning you had to keep the recorder in a pocket away from the mic. While still not silent, the better rigidity and metal case of the RH1 seem to have reduced that scraping noise greatly. Other niceties include the capability to digitally transfer to the PC recordings made using the analogue ports of older MD recorders (this was never possible before owing to the stranglehold of Sony's proprietary format and overzealous copyright protection policy), and Mac support for the transfer program.
In conclusion, this is an excellent little machine and a definite recommendation to a starting wildlife sound recordist in preference to cheap CF recorders with their noisy microphone preamps (at the time of writing, 2006. Hopefully this will improve as manufacturers get the message and/or discover Sony's choice of A/D and preamp chip!). The cost is around £230 inc vat at the time of writing. Team this up with an integrated battery powered mic like the Sennheiser ME series and you have a good portable setup, and the noise performance means the recorder won't hold you back even if you to go all the way to the Sennheiser MKH range (using an appropriate outboard 48V phantom power adaptor)
This is currently Sony's only HiMD recorder in the range at the time of writing (Autumn 2006) and there has to be a question mark over the commercial future of MD. The portable music playback market MD was originally targeted at in 1993 has moved comprehensively to the ipod approach, leaving mindisc in a field recording niche which is being encroached by CF solid state recorders. However, for the wildlife sound recordist this is not a great issue, as the machine allows you to record uncompressed PCM 44.1kHz 16 bit stereo and transfer it losslessly to your computer for editing and archiving. You would be wise, however, to not anticipate being able to read MDs in 20-30 years time. Although the discs may keep the data that long, and indeed may outlive cheap CD-Rs, working players and software may be thin on the ground.
On the upside, however, HiMD offers advantages that low/midrange CF field recorders don't :
- the media are cheap - about a tenth of the price of the equivalent 1Gb CF cards. This meant the MD recordist can run for long periods in the field filling MD blanks without needing to download the recordings to a PC. In principle the recordings can be edited in the field, though there is a body of anecdotal opinion suggesting this is best avoided as it may cause problems in downloading recordings.
- low noise mic preamps - Sony's MZ-NH1 units when used with a direct NiMH battery phantom PSU has a distinct edge on the lower end of the CF recorders for input stage noise.
The conclusion is that MiniDisc can offer the cash-strapped recordist recording at 44.1k/16bits a better potential signal quality compared to the low-end solid state CF recorders targeted at the musician/garage band market where sound levels are much higher than nature recordings.
Performing some more detailed measurements with the unit essentially repeating the ones done for the NH700, using the same test rig as before the noise performance was at a very similar level to the NH700. This is not tremendously surprising as the service manuals for both recorders show both use the AK5356VN chip for analogue to digital conversion.
RH-1 in green, NH700 in white, test conditions as before
The base level of the noise is ever so slightly lower with the NH1 except at low frequencies, and if the noise is boosted by 40dB a soft hum can be heard in the noise. The machine was not mains powered and all test equipment had been turned off, but a spectrum analysis of the noise showed components at 50, 100, 150 and 200Hz. There is also a small peak around 5kHz. At first I blamed this on AC hum but I noticed the flicker of the OLED display out of the corner of my eye. Using a photosensor I found this was refreshed at exactly 100Hz (with other components in the waveform) so it could be the source of these components. There is another small noise peak at 4.7kHz and a component at 15.4kHz. However, this should be taken into perspective - these peaks are likely to be on a par with the self-noise of a Sennheiser mic, and the noise performance is way ahead of the mediocre input stages of cheap CF recorders such as the Microtrack (listen to Rob Danielson's test on the HiMD noise performance page to hear that).
input levels required for 0dBFS on Sony MZ-RH1, test conditions as before The similarity with the NH700 is quite remarkable, indeed the differences probably lie within the bounds of experimental error!
you can read more about the measurements of