What kind of SD card should I use?

Working with SD cards

The Idoru P-1 comes with an A1 32GB SD card that is already correctly formatted as FAT32, and ready to use for your Idoru session.

Use a good-quality SD card with your P-1. Cheap or unsuitable cards could cause audio glitches, dropouts, or timing issues during playback.

What kind of SD card should I use?

We recommend a 32GB A1 rated SDHC card.

The P-1 supports SD, SDHC, and SDXC cards. The most important spec is random read speed, not the sequential read/write speed printed on the front of the card.

This distinction matters because most SD card marketing (MB/s figures, UHS-I/UHS-II, "V" video speed classes) describes sequential transfer speed — how fast the card streams one long continuous file. That's the number that matters for recording 4K video. It is not a reliable indicator of how the card performs when reading lots of small audio chunks scattered across the card, which is what the P-1 actually does during playback. A card can have an impressive headline speed and still perform poorly for this kind of access pattern.

The spec that does describe this is the card's Application Performance Class (A1 or A2). This is a guarantee of minimum random read/write performance, and it's the rating we recommend you check for, rather than sequential MB/s or UHS class. We recommend a Class 10, A1-rated card, such as this one.

<aside> 💡

A few other practical notes:

• Use a 32GB A1 rated SDHC card. They're large enough for around 50 hours of 16-bit/44.1kHz WAV files, and they use FAT32 as their standard format. Larger cards (64GB+) are SDXC, which uses exFAT by default — see "How to format your SD card" below.
• Avoid cards aimed at high-end video work (UHS-II, V60/V90, "Tough"/rugged ranges). They're optimised and binned for sustained sequential throughput, which isn't the performance characteristic the P-1 needs, and we've seen these underperform cards with a much more modest sequential spec.
• The card must be formatted as FAT32. If it's a 32GB card, it's usually already FAT32 out of the box. This caps usable storage at 32GB even if the card itself is larger. </aside>

<aside> ⚠️  SD cards with known issues

We've identified specific cards that cause problems with the P-1. Please avoid these:

SanDisk Extreme PLUS SDHC 100 MB/s UHS-I U3 Class10 32GB

</aside>

How to format your SD card as FAT32

Most 32GB cards arrive already correctly formatted, so they are ready to use in the P-1. How you format one yourself depends on the card's capacity: the SD specification assigns FAT32 to cards up to 32GB (SDHC) and exFAT to cards above that (SDXC).

32GB or smaller (SDHC)

These cards use FAT32 as their standard format. We recommend the official SD Memory Card Formatter, as it follows the SD Association's recommended settings for the card exactly — Disk Utility or Windows' Format dialog will also produce a working FAT32 card, but the official tool is the safest default.