A U R O R A P l u g - i n s
Aurora requires some low-cost additional devices to be purchased:
- A powerful PC: the minimum is a Pentium-166 with 32 Mbytes RAM, 3 Gbyte Hard Disk, and a CD-ROM. Actual recommendation is for a Pentium III 700 MHz, 128 Mbytes RAM, a 20 Gbytes hard disk, and an 32x CD-ROM capable of direct digital reading of "orange book" CD-Audio disks.
- a good quality, 16, 20 or 24 bits analog sound card: recommended are the ECHO family of 24-bits soundcards. All these are capable of simultaneous playback and recording, thus enabling real-time binaural MLS or sweep measurements. Although the new full-duplex drivers available at Creative Labs make it possible to use also an original Sound Blaster 16, SB-32 or AWE-32 sound card under Windows95/98, we do not recommend these boards (and their even worst compatibles), which are not really capable of true 16-bits full-duplex operation. Also the more recent Sound Blaster Audigy is NOT full-duplex! Looking toward future, anyway, we suggest to purchase a multi-channel sound card, possibly with at least 8 indipendent channels, such as the new Layla3G, the MOTU, the AARDVARK cards, or the Firewire or USB2 external audio interfaces manufactured by Edirol and ESI.
- Notebook users, beware of the fact that most sound chips encountered on top-brand notebooks are awful! For example, I recently purchased a DELL notebook equipped with an ESS Maestro-2E sound chip, which exhibits severe clocking problems in full-duplex operation. Reasonably good sound chips for notebooks are instead the Crystal or the Yamaha OPL3. If Your notebook has an awful sound chip (or is not full-duplex, or does not even have the line-in connector), there are actually only two options for an additional, self-powered sound board: the Digigram VX-Pocket PCMCIA board (great, but expensive), or an external USB sound card. We have tested succesfully both ESI (Waveterminal U24) and Edirol (UA-25) external USB cards.
- A CD-ROM drive capable of direct digital reading of CD-AUDIO disks is recommended, to make easy to get anechoic samples in .WAV format from commercial audio CDs (most recent CD or DVD drives are capable of digital audio extraction nowadays). Anyway, the Aurora Web Site , also available on CD-ROM (which can be ordered separately) already contains dozens of anechoic samples in .WAV format.
- a binaural microphone (SONY DR-W70C or SENNHEISER MKE2002set); a good binaural microphone can also be built with spare parts: 2 good quality Lavalier microphones can easily be fitted inside Your ear channels, including them in wax plugs. Also CoreSound and Sonic Studios produce low-cost, high quality binaural microphones.
- a DAT or Hard Disk recorder for not-realtime measurements (if You don't like to connect long cables between the microphones and the PC, or if Your sound board is not capable of simultaneous playback&record). We do not suggest to use MiniDisc or other digital recorders based on lossy compression methods.
- an omnidirectional loudspeaker (a special dodechadreon has been developed, and it is available on request).
- an high quality headphone for binaural reproduction (the frequency response can anyway be easily equalised), as the SONY DR-W70C which includes both microphones and speakers - for professional results, we use Sennheiser HD-560 headphones.
- a dummy head (if You don't like to use your own!), as the one included with the Sennheiser MKE2002set. We DO NOT SUGGEST to use expensive dummy heads, with internal microphones, as the Kemar, the Bruel&Kjaer type 4128, the Cortex or the Head Acoustics HMS-III. Instead, we suggest cheaper "recording" dummy heads, such as Senhheiser MKE2002set, SONY DR-W70C, Neumann KU-100, or the new B&K 4100. All these have microphones at the ear channel entrance, and thus do not exhibit a strong resonance peak, which is usually difficult to equalize out.
- a small hemi-anechoic chamber for loudspeaker reproduction (a special portable anechoic seat has been developed, and it is available on request - this is particularly important for Ambisonics reproduction with 6-8 channels).
- a number of high fidelity loudspeakers, to be installed in the listening chamber.