I’ve had no issues recording on SD with my cq20b for awhile, so didn’t think anything of it when I did a stretch of 3 shows recording to SD.
Unfortunately, they all have an issue where every few seconds the recording jumps a few seconds. In other words, I’m missing small split seconds of recording where the audio drops a word fraction of beat, but continues on (rather than inserting silence).
All the recordings used the same SD card, and were fairly high on the multitrack channel count (like 16-18 channels recording simultaneously). Knee-jerk reaction is to blame either of those two things, but I REALLY need to know what the issue actually was if I hope to lessen the likelyhood of it happening again.
How can I troubleshoot this to determine what is causing this issue? One of the shows was for a live video recording, so I’m bracing myself to swallow my pride and admit to the client that my gear failed and I didn’t run a simultaneous recording through the USB interface.
Hi,
I’ve just experienced the same problem, however I am using the recommended SDHC card. (Samsung EVOplus 32GB) I carefully checked the requirements before purchasing as to avoid problems.
I have successfully recorded my band playing live (pub band, 2 separate sets, around 1 hour each, only recording 7 inputs @96kHz). I transferred the files across to my computer and the results were very good.
Recently I recorded a rehearsal with my other band (this time recording 9 inputs @ 96kHz) to find the audio skipping, similar to a CD skipping. Completely unusable. I tried the same diagnostics as yourself, checking in a different DAW. Tried to copy the files across again, in case the transfer wasn’t successful. Played the files back on the CQ itself. All had the skipping occur.
As I’m using the recommended SD card from A&H and formatting the card in the unit between each use, I think this is a fault in the unit/firmware and not user or SD card error.
It could be the source point I’m recording from (post preamp) although this didn’t cause problems before. It could be that I’m recording at 96kHz and the SD card cannot cope with the write speed with more than 7 tracks with EQs and compressors on the tracks. Although the A&H website doesn’t state these as being and issue and only recommends using different recording quality for length of time.
Next time I will be trying a different source point and recording at 48kHz.
Ok, so first, post preamp does not record FX or EQ or anything else. It’s actually the first point in the stream you can record. That’s the best way to record as you really don’t want EQ, Compression, FX or anything like that on your recordings. You want to make those decision after you record. So leave it at post preamp. And it’s also the way to record for doing “virtual soundchecks” which is a very valuable feature. You can record the band, play it back, and adjust everything in the CQ to sound good.
Second, I really don’t understand why anyone records at 96K! Yea, I get it, if you don’t know what you’re doing you always default to what you think is the highest quality. Do you realize that most professional studios don’t record at 96k? Actually many of them don’t even record at 48K, they record at 44.1K. CD’s are 44.1K! So is your band rehearsal better quality than millions of CDs from famous artists? Probably not. Most studios these days are recording at or are converting to 48K. But not because of quality, it’s because that’s the standard format for video and many recordings now are also doing some type of video.
And the studios that ARE recording at 96K, are the ones with the highest quality of everything… Microphones that cost many thousands of dollars, FX gear costing in the many thousands of dollars, grand pianos, huge expensive rooms, etc. etc. And they are recording the top acts in the world. They aren’t using a CQ! The only reason these low end products even offer 96K is two fold, one the chips do it so why not, two every one of their competitors is doing it. If you don’t do it, someone will buy another product because it has it, even though they should actually NEVER use it.
Trust me, just set the thing to 48K and NEVER change it! You’ll thank me later!
Ok, so first, post preamp does not record FX or EQ or anything else. It’s actually the first point in the stream you can record. That’s the best way to record as you really don’t want EQ, Compression, FX or anything like that on your recordings. You want to make those decision after you record. So leave it at post preamp. And it’s also the way to record for doing “virtual soundchecks” which is a very valuable feature. You can record the band, play it back, and adjust everything in the CQ to sound good.
Keep in mind a “virtual sound check” does not take into account any live stage volume, guitar amps, drums ect.
If your band uses stage monitors bring those up during a virtual sound check.
Keep in mind a “virtual sound check” does not take into account any live stage volume, guitar amps, drums ect.
If your band uses stage monitors bring those up during a virtual sound check.
Correct! But if you don’t have a sound guy, it’s a start.
Thanks for the information. I will continue to go for ‘post preamp’ as the recording source as the unaffected tracks is what I’m after. This is something I wasn’t completely sure about, but makes sense.
For me the unit defaulted to 96kHz so I just stuck with it. I’m not under any misconception that I’m trying to outdo the quality of professional recordings. The recordings are just for the band members to listen back to and for me to practice mixing a live recording in my DAW. I went with the default and the results were fine the first time using it so I continued to do so. I’m still yet to find out if it will remedy the ‘skipping’ problem that the OP and myself are experiencing as it didn’t affect my recordings the first time round, it seems to be the most likely reason behind this, so thank you for reaffirming this.
I’m still learning the ins and outs of this unit and this new (to myself) technology. I’m thoroughly enjoying stepping away from the analogue desks I’m used to.
as i have written here: SD card specs?
the definition of SDHC and UHS-I does not define the write speed of the SD card.
Looking again in the definitions of the SD Association, I found that the use of a SD card with the Video Speed Class 30 (V30) meight be the safest bet, as this ensures a permanent writing speed of 30 MB/s.
I use SanDisk Extreme PRO SD cards by myself. I have done only one reccording with my CQ20-B till now: I reccorded up to 15 channels at 96 kHz and could not find any Issued with missing samples (skipping).
I am having the same issues with SDHC cards. It records fine for a while (3 songs sometimes 5-6 songs and then starts skipping.). I lose half a second to a full 2-3 seconds of the tracks. It sounds really weird on playback. I am on my 3rd card and having the same issues. The latest card is a SANDISK Ultra Plus SDHC 32GB Class 10 rated at 130 MB/s. (The first two cards were older Class 10 's from my DSLR, so OK they might be old.) This last card was brand new from Amazon. Can someone please point me to a list of FULLY APPROVED and verified cards? I don’t like losing session recordings to misbehaving media…
Hit this myself the other day still not fully resolved as to why it happened as I was using a Sandisk SDHC card as displayed in the A&H info about card compatibility. It feels like a processing overload where the processor can’t keep up with all the activity it needs to do if fully using mixer features. But theres no info on what the actual processor is in the mixer to try to check that theory. Quick fix to reduce load is to simply switch to 48K samples, but the specs indicate 96K should be OK so it shouldn’t be necessary.
So got to keep researching this one. Any feedback on the cards in use when glitching would be useful.
My reading showed the Mixer hardware is designed for SDHC cards only. It cannot format SDXC cards to FAT32 properly in the mixer. You only discover that on playback though or reading the details about the differences in SDXC. On my test a SDXC card formatted, accepted recordings, but stated it could not play back. Copying the recorded files to the computer showed the file header was corrupt so the file systems cannot read.
Whilst the mixer hardware only works with SDHC cards it can handle higher storage SDXC cards where they are formatted to FAT32 on a computer.
Windows computers need special formatting software to do that nowadays given FAT32 spec limitations, Macs have it built in.
Any preformatted SDXC cards purchased will, because of higher capacities be formatted as exFAT not FAT32.
Hope these observations are of use to some, but I still have the problem of a supposed compatible card glitching on record/playback and still do not know why.
Still thinking about this Audio Dropout issue and potential causes.
I had been using new SD cards since acquiring my mixer a few months back.
The cards are all SanDisk Ultra SDHC Class 10 U1 32GB
Channel count being recorded including LR main mix around 12.
Last two sessions at 96K no real overhead differences obvious.
One session Ok, last session dropouts
Prompted two thoughts here:
1: The file system, being FAT32, is sensitive to corruption if unfinished read/write cycles at switch off. So need to observe how I end sessions in case I’m causing the problem. No easy way to see if all read/write cycles complete ie saving a scene will cause read / write to USB.
What if i turned off before that was complete and the next switch on defaults to loading a corrupted / incomplete file, could that cause dropouts?
2: No idea what the processor is in the mixer so could it be a processor loading /bandwidth type issue?
I remember the days of the Sinclair QL 68000 chip. Sinclair was using chips rejected by quality control of expensive computers and as his QL didn’t need the full processor power he was able to produce a cheaper machine but still had the functionality he needed for it to work.
Could it be, the adventurous CQ users who are loading all the features at recording point, are the only ones noticing the dropout problem?
Again its just a thought re observing and troubleshooting the issue. We would need the A&H tech view on this one as they know their chipsets and testing activity. But if its hardware there could be a big warranty cost factor, so those in the know may not be willing or able to be transparent. Im inclined to believe A&H tech support would want to get to the bottom of any problems found in the wild.
My next test is to drop 96K recording even though it should be no issue.
You record for CD? Who listens to CDs? Sorry, but that rational doesn’t apply today. Sure it’s a lighter load at 48k but what’s the bit depth? That will cause a hiccup faster that sampling speed. I would offer the user to try stepping down slowly. Go from 96k/32bit to 96k/24 and then to 16 bit before dropping to 48k. If you got to try 48k then go with the biggest depth as possible.
Useful observation re sample rate v bit depth. I think we’ve only got 24bit in the CQ hardware, either at 48/96. So can’t save any CQ processor overhead via bit rate change on multi stream record to card or to computer (or at least a Mac with core audio). So only the switch to 48k from 96k.
Been doing some testing with SDXC v SDHC cards on the mixer. So thought Id post my observations.
The two cards Ive been testing with are.
SanDisk Ultra (120mbs read) Class 10 U1 SDHC 32Gb
Kingston Canvas Select Plus Class 10 U1 SDXC 64Gb
The recommendations from A&H are SDHC cards only
My findings
Its possible to use SDXC but you must:
1: Format the card on the computer the mixer won’t do it
2: Ensure you Format to FAT32 file system (MBR best) On a Mac the Disk Util will do it on Windows you need extra formatting software as the OS won’t do it. The mixer only works with FAT32 File System.
3: Manually recreate the Folder Structure the mixer requires to write the multi stream recording files to. The Mixer Format utility appears to format and write the folder structure as part of the format process.
What I didn’t test is whether a format of an SDHC card on the computer without putting the Folder structure on it manually would allow the mixer to record correctly. With the SDXC card it wrote files but their file headers were corrupted so no playback possible.
SDXC can then give you three arguable benefits
1: Slightly higher write speeds. (SanDisk SDHC 36mbs write 120 Read Kingston SDXC 40mbs write 90 Read)
2: Higher storage capacity (whether thats a benefit depends on your workflow in normal day to day use)
3: The card is later tech and can probably be used in more devices going forward.
Having been able to identify the specific cause of the audio dropout issue yet so yet to see whether the marginal increase in card write speed makes a difference, that will have to wait till next rehearsal. But using 48K in place of 96K sample rate ought to give lower processor overhead. However given the Sandisk Card is the one A&H show in their information re SD Card compatibility and appears well within the bandwidth specs for audio recording you would have believed that it shouldn’t be the cause of the multi stream recording dropouts.
