What is the largest SD card storage size compatible with a Qu-7? I know that the manual states 32Gb; however, frequently the manual lists what was tested by the manufacturer, not necessarily all options which can be used.
Hi there,
The SD card slot on the Qu-7 meets the SDHC specification. SDHC has a maximum card size of 32GB, which is why the manual states this.
You can use SDXC cards which go much bigger, however we can’t guarantee performance and compatibility of any particular card as SDXC is not strictly speaking in-spec.
That said however, there are plenty of SDXC cards that will work perfectly. A good rule of thumb is to aim for as much performance as possible - I’ve got an SDXC card that works fine that is rated to 300mb/s - I wouldn’t go much below this number.
(The boring technical reason for this is that SDXC can sometimes use different methods to achieve the faster speeds like the extra pins found on UHS II cards…the Qu can’t read those, so any performance benefits gained from having them are not realised)
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Thanks Mark. I have 32 Gb SD cards that are according to Allen & Heath specs. They are SanDisk, with a speed of 100 Mb/s read. I could not find many cards at all that were faster than that, and none approaching 300Mb/s. Is this latter speed a suggestion for all cards, or only SDXC cards.
Just have a look there: Recommended SD cards for new Qu series?
Correct - you’ll only find speeds considerably faster than 100Mb/s if you are looking at out-of-spec SDXC cards
The following confuses me:
I don’t think such specifications are correct, because I’m quite certain that not just here in Germany: Mb/s = Mbit/s and MB/s = MByte/s.
And on all the storage media I can buy here, the values ​​are always given in MB(yte)/s.
Furthermore, it always confuses me that obvious read speeds are specified or recommended, even though the usually much lower write speeds would be the decisive factor.
And to my knowledge, there’s no conversion formula that would allow you to say, 100 MB/s read equals 50 MB/s write.
And another question for A&H:
When recording or playing back, the calculated maximum data transfer rate is only about 4.6 MB/s in total.
Is there any formula that shows how much higher the data transfer rate needs to be, because the writing process is divided into up to 16 or 32 processes depending on the sample rate, and therefore speeds that are actually 10 to 20 times higher are needed?
There’s always the possibility that the person typing wasn’t paying attention to proper capitalisation on this occasion! 
I meant MB/s as is typically printed on SD cards.
There’s no formula that I know of to calculate the actual data transfer rate - it’s why I’d always personally recommend buying the fastest card that meets your budget.
Of course this is also complicated further by there being lots of fake SD cards available in the market…
Thanks for the quick “confession”, but my last - the crucial - question unfortunately remained unanswered …
With a conventional mechanical hard drive, it was logical that writing up to 16 or 32 tracks in parallel takes significantly longer because the read/write head has to move constantly.
However, this delay doesn’t exist with an electronic hard drive or SD card.
So, what speed is needed to record the maximum of 32 times 144kB/s in parallel?
The internet say (and I thought always the same) that the required speed is the same as for a single track at 4.6MB/s, and therefore C10 or U1 = 10MB/s would be more than sufficient.
But what does A&H say in practice?
But I read the following link, which deals with exactly this topic:
While it might seem easier and better to simply use the highest and fastest SD Card, this doesn’t always result in the best performance.