PORTADISC FAQ

What is the latest firmware version?
The latest software for the PORTADISC MDP 500 is version 1.20. The version is shown briefly after power up on the MDP’s boot-up page. If your MDP contains a version other than v1.20, contact your dealer for instructions on getting your MDP updated to the current release.

What is ATRAC 4.5 encoding?
ATRAC stands for Adaptive TRansform Acoustic Coding and was developed for SONY to be used in the MiniDisc format. ATRAC allows up to 80 minutes of stereo audio to be stored on a disc much smaller than a 12cm diameter CD. It achieves this by reducing the data rate to and from disc to approximately 20% of the 44.1, 16 bit PCM data rate associated with CD. ATRAC uses various psycho-acoustical phenomena such as masking to remove audio data that is considered to be undetectable by the human ear. The first versions of the ATRAC algorithm were not too effective, but version 4.5 has reached a stage of maturity whereby most find it is extremely difficult or near impossible to tell a difference between the audio quality of the compressed and the uncompressed signals. One should not confuse ATRAC 4.5 with the more recent ATRAC3. ATRAC3 uses 10:1 (MDLP2) or 20:1 (MDLP4) compression as compared to the ATRAC 4.5, which uses 5:1 compression and is much higher quality. ATRAC 3 relates more closely to MP3 quality.

What is EFM (Eight to Fourteen Modulation)?
The EFM modulation technique is used in the MD format to convert 8-bit encoded data into 14-bit data. This is done to create an adequate pit/land density ratio that will provide optimum disc tracking and transmission characteristics.

Can I transfer files between the MDP and a computer using the USB interface?
The MDP’s USB interface is for real-time audio transfers. Standard drivers included in Windows 98SE/2000/Me and Macintosh OS 9 and above recognize the MDP as a 'USB Audio Device'. This protocol only allows for real-time streaming audio to and from the PORTADISC.

Can I use the MDP and USB with Audio Editing applications on the Windows NT platform?
No, not with USB. Windows NT does not support the USB Audio protocol, but any audio editing system that uses the NT platform, and has an interface that employs optical or coaxial SPDIF inputs and outputs, is of course quite suitable for transferring audio to and from the PORTADISC.

Does the USB connection require special drivers for the Mac or Windows platform?
No. The drivers for USB Audio are part of the Windows OS (in Win98SE, WinME and Win2000) and Mac OS 9. Just plug in the USB cable and the computer operating system should do the rest.

What audio file format does the PORTADISC use for saving files on a computer?
This is not determined by the PORTADISC but by the software application. The PORTADISC outputs 44.1k, 16-bit PCM data which is the same format as CD. You can save this data in whatever file format you choose, as long as the software application supports this. Common file types may include wav, aiff, SDII, etc.

Do I need special applications to stream audio via USB?
No. You only need a compatible operating system (Windows 98SE/2000/Me and Macintosh OS 9 and above). With the proper OS, all basic Windows and Macintosh audio editing software that uses the computer’s sound card is probably compatible with USB streaming audio. If the editing system uses its own interface boxes (e.g. Pro Tools), then it will probably not be able to use USB audio, unless of course SPDIF digital I/O is available.

Can I perform faster-than-real-time transfers when using USB?
No. The current transfer speed is limited to real time by the decoding system from ATRAC to linear PCM. This real-time decoding must occur before the transfer by USB streaming audio.

Can I record more than 80 minutes on a single MD80 disc?
No, not in stereo mode. The stereo record time maximum is 80 minutes, but in MONO record mode, this is doubled to 160 minutes (2 hours 40 minutes).

What converters are used on the MDP?
The MDP uses latest-generation 20-bit oversampling Delta-Sigma modulation converters.

Can I overcharge NiMH in the portadisc?
It is not possible to overcharge batteries in the PORTADISC when using the supplied mains adapter. If you are using a non-standard DC supply then ensure that the output of this does not exceed 14 volts.

What is the sample rate and word length for recording and playback on the MDP?
The MDP records 20-bit/44.1k audio and then encodes using ATRAC for storage onto the Mini Disc. Playback is at 20-bit/44.1k out of the SPDIF coaxial and optical outputs.

What is SRC?
SRC stands for Sample Rate Converter. The MDP employs automatic sample rate conversion for digital audio input that is not at the 44.1k sample rate. The SRC converts incoming digital audio between 32k and 48k into 44.1k.

Can I turn SRC off?
The SRC automatically turns off if the digital audio input is already at a sampling rate of 44.1k. This ensures the signal path is as clean as possible. SRC only turns on for signals outside the range 44.1k +/-0.1% (e.g. 48k and 32k).

How long should I charge the batteries for optimum performance?
If the batteries are charged in the PORTADISC, optimum battery performance is reached after 14 hours of charging. A 14-hour charge should provide approximately 3.5 hours of operation in record mode (i.e. operating immediately after a full charge with the backlight off and phantom power off). For faster charging, third-party fast chargers for NiMH batteries can be used. With these devices, charge times are a little as 5 hours.

What is SCMS?
SCMS (Serial Copy Management System) allows the originator to protect their material from unlimited digital copying. The system has 3 settings: 1) Copy Prohibit
2) One copy allowed
3) Copies permitted

The PORTADISC’s analog recordings are default set to ‘one copy allowed’ and cannot be changed. SCMS does not prevent analog copying or streaming to a computer via USB.

Can I turn SCMS off?
No. SCMS is part of the MiniDisc specification and cannot be disabled.

Does the use of phantom power dramatically affect my battery performance?
This depends on which phantom-powered mics are being used and whether there are 1 or 2 phantom mics connected. The PORTADISC limits the current to each input mic to 7ma, or 14ma total. This equates to a maximum power drain of 670mW. This results in a maximum reduction of 30 minutes in record time. If just one phantom mic is being used, then the reduction is about 15 minutes.

Can I use NiMH batteries that do not provide a minimum 1500 mAh?
Yes, you can use any capacity size provided the terminal voltage is the same (nominal 12V). However, the smaller the battery's capacity, the shorter the operation time.

When I record in mono mode, playback is on both left and right channels and the output level is 6dB lower than the indicated record level. What’s going on?
A 6dB digital attenuator is automatically turned on in MONO record mode in order to prevent an overload situation occurring. For example:-

Left input gives a signal of 0dBFS on meter.

Right input gives a signal of 0dBFS on meter.

MONO (i.e. add) the inputs together to give a signal of +6dBFS (6dB increase = double the voltage amplitude).

+6dBFS exceeds the maximum allowable level by 6dB and would result in severe distortion. Therefore a 6dB attenuator is switched into the MONO signal path to reduce the level back to 0dBFS when monitoring both Left and Right outputs.

What parameters are stored in the User Setups?
The five user memories store the user-selections for the following parameters:

INPUT MENU	SYSTEM MENU
INPUT SOURCE	REC MODE?
MIC-ATT	TRACK-INCREMENT?
BASSCUT	THRESHOLD LEVEL
LIMITER	AUTO-START/CUT?
PHANTOM	AUTO-PAUSE?
	PRE-RECORD?

Is there a remote available for the PORTADISC?
HHB does not produce a remote for the PORTADISC. However, a remote is easily implemented by using switches to short the various pins of the connector together. The pin-out diagram and remote information are located in the operations manual.

Do I get extended recording times when using a dynamic mic vs a condenser mic?
Yes and no. If phantom power is required, then recording time will be reduced - by how much depends on the microphone. If the condenser is powered by an external battery, then recording time should be unaffected.

Can I use the internal mic for critical recording?
This is not recommended. The internal mic is intended mainly for logging purposes.

How do I preserve battery life when the unit will be idle for extended periods?
When the PORTADISC is not in use, it is best to remove the batteries and store them at room temperature out of direct sunlight. All batteries self-discharge over time so ensure that the batteries are charged for a full 14 hours before use.

Is the PORTADISC’s mic pre bypassed when switched to line input or is the input simply padded?
For line-level inputs, the input is padded.