DP-24 Pops and Clicks

[Dennis FMRJE]

Roundhill, Make sure you Tascam tells you what the details of the fix; it good to understand the technology and understand the solution. Have them confirm the 24bit dilemma. Let me/forum know how long the fix takes. Thanks for checking fmrje.

 

[eric_the_b]

Back up the card on your pc then give the card a FULL FORMAT on the DP32 and prob solved ! I was amazed and very pleased!

 

[Dennis FMRJE]

Yeah I hope that would work; I purchased the SanDisk Extreme Pro and did the full format; re-initilized the DP24-the spikes still occurred when recording at 24bit. But when recording at 16bit no spikes occur. I had explore all the solutions. Are you recording at 24bit?

 

[eric_the_b]

Thats really disappointing (tell me about it, he says!)

I always record in 24 bit and no longer get the spikes. very odd! Ive tried three different makes and sizes of card and still no prob. i'm getting twitchy now, and hoping that I dont start getting them
again. will keep you posted if I come up with anything

 

[Dennis FMRJE]

That's sounds positive eb; for me the spikes appear when in/out points are created; those spikes suck and hopefully they don't appear again for you; keep me posted on any updates. Roundhill said he is shipping his DP 24 back to Tascam for the spike fix; I want to know what the detail of the fix is.

 

[eric_the_b]

Mine have reappeared again!! Def going back to Tascam. For me, the spikes appear when I create in/out points and use either the IN button or Jog wheel to get to them BUT only when I'm recording vocals. If I lay down just my guitar and drums first, I get no spikes until then! I wonder, therefore, if it has anything to do with the Phantom Power? Who knows! (?)

I did wonder if it matters if you format the disk in 16bit of 24bit mode, but I doubt it!

I think the legal term "not fit for purpose" is relevant here? I think Tascam need to refund in full - unless they can come up with a sure-fire fix (which I'm starting to doubt)

 

[joslenior]

If the problem is 24-bit related, as indicated in several earlier posts, there might be a connection with the undo feature. For every change on any file there is information recorded not just on that file but also on copies to be able to perform an undo. This information is much larger on 24-bit. Also the undo setting for undo 10-steps might be of influence. I bought my DP32SD recently and can send the unit back with full refund within 60 days. If Tascam doesn't come with a solution I'll return the unit.

 

[Dennis FMRJE]

Joslenior, I tried your undo suggestion by changing it from 10 to 1; unfortunately the spike remained in place on the 24 bit recording; recording in 16 bit at 44.1k/48k no spikes are heard on both of my two 24p's. I just don't want to have my dp's not in my studio. Unless I hear the Tascam tech solution and the guarantee turn around time. I will pay the shipping cost to get the dip's fixed. Recording at 24 bit is powerful data (65k more) capture vs 16 bit especially in the recording/mix down phase (even though not heard by non-audiofiles) but I dig the fact of 24 bit technology. Noted by Roundhill in the previous post, perhaps it is not spike plague because most people don't record in 24bit. I definitely want to know the tech reason for the spikes!

 

[joslenior]

Dennis, I fully agree. We bought units able to record in 24 bits and Tascam has to come up with a solution. On the Zoom forum there is a lot of discussion on sd cards and some users are convinced that class 10 cards are not suited for our purpose because of the way the cards are organised. They were originally ment for video recording which is a long continues stream of data without random access actions. Are there any members on this forum who tried class 6 cards on 24 bit recording? Would be very interesting to learn their findings.

 

[Sam Trenholme]

I had the same problem; I had a multi-tracked song: 24-bit, 44.1 khz, nine tracks. As I was putting on new tracks, the click problem was unbearable. To remove the clicks:

• Using the audio depot, I exported the tracks as 24-bit wav files
• I opened up a new 16-bit 44.1 khz song
• The audio depot refused to impot and convert the 24-bit 44.1 waves to put them in the 16-bit song
• Using Audacity in my PC, I converted the 24-bit wav files in to 16-bit wav files
• I imported all of those in to the 16-bit song
• At this point, I was able to lay down another stereo track without the nasty pops

Some relevant technical details:

• The SD card I am using is a San Disk SDSDX-032G 45 MB/s card (300x). This SDSDX-032G is listed as one of the compatible cards.
• Since this might be an issue with the card (and not the DSP/CPU in the DP-32SD), I have just ordered a pair of SDSDXPA-032G-AFFP (32 gigs, up to 95 MB/second read and 90 MB/s write) to see if that improves things with 24/44.1 recordings (keep in mind that 32 tracks of 24/44.1 is only 4,233,600 bytes of data a second, but “up to” gives San Disk a lot of wiggle room). If I still get pops at 24/44.1, I can go all-out and try the SDSDXPB-032G-A46, which goes up to 280 mb/second but costs a pretty penny (but keep in mind even this high-end-card has three times the capacity and one third the cost of 2” tape running at 15ips)
  
• The way the Tascam handles punch-ins is by having a different file for each punch in. This may or may not be related to the problem (since the audio depot export/import process makes a given track a single .wav file instead of a bunch of spliced .wav files)
• My undo level is 1, not 10 (I come from the era when recording on an armed track meant bye-bye to whatever was on that track before)

Edit: Looking at the SDHC spec some more, the maximum speed a standard SDHC has is 25 MB/second, and high-end cards like the SDSDXPB-032G-A46 need a special UHS bus (which the DP-32SD doesn’t have) to write 250 megabytes a second. The issue may be that these SD cards just can’t handle reading 3.1 megabytes per second while writing over a megabyte a second, changing the file being read (since each punch-in creates a new file in the DP series) — they are designed for camera users who are either reading or writing, but not doing both at the same time. I get the sense the answer may be “yeah, these critters have 24-bit audio, but only if you aren’t doing a lot of overdubs and punch-ins”. Also: I’m not sure the dynamic range of the converters is over 90db; if not, 24-bit is completely pointless.

 

[Dennis FMRJE]

Sam, I did all the research and tasks to eliminate the dreadful spikes; the extreme Pro high end card I used had 95MB read/write capability, still got the spikes. There were no spikes when I record at 16bit/48k. 24bit gives you 65k more data resolution than 16bit. Unless you want to send your DP back to Tascam, record at 16bit. It would be good to hear from Tascam what is the root cause of the 24bit spiking, they just say that only a few are getting the problem.

 

[Sam Trenholme]

Agreed: It looks like the issue with 24-bit recording and pops is not a SD card issue. Indeed, if there was an issue with the I/O to the card, it would be logical for the DP-32SD (or DP-24, as the case may be) to show “Device Error” or what not to indicate there is a problem with the card. Or maybe there would be a brief moment of silence — the logical thing to do when there is an issue reading or writing is to mute things.

What makes no sense is for a unit to act the way the Tascam DP series does: Create a momentary impulse at full digital volume; that indicates a bug. A noise like that can blow a speaker. It is something Tascam needs to fix with a firmware upgrade. The sense I am getting is that Tascam’s SQA department does the majority of their tests with 16-bit recordings, so this bug hasn’t shown up in their internal testing.

What we can do to help Tascam is make a simple song — probably with a lot of punch-ins — showing the problem. Having it be a reproducible test case is the first step in finding and fixing the bug (Yes, one of the hats I wear at my day job is being a professional SQA developer).

For the record: I am using a supported card and did format it in the Tascam DP-32SD.

 

[Dennis FMRJE]

I appreciate your remarks Sam, earlier responses to this post indicated this was an anomaly only happening to a few DP's out of 50,000 DPs sold but I think those whose are experiencing the spikes during 24bit recording have verified their is something Tascam should check on by doing Q/A with 24 bit recording. With Tascam tech advice, I had done all of their suggestions (re-initialize, new card, disconnect any device connected to the DP, etc) except for sending them my DP24's. I believe Tascam monitors this forum as well as heard from its customers. Hopefully they will explain the problem and derive a solution we can use. Those spikes are nasty on the ears and on the monitor speakers. I want my 24bit resolution/revolution!

 

[Roundhill]

What we can do to help Tascam is make a simple song — probably with a lot of punch-ins — showing the problem. Having it be a reproducible test case is the first step in finding and fixing the bug

I have done this. TASCAM received my DP-24 two weeks ago to try and fix this issue. I have heard nothing back yet, but when I do I'll keep everyone posted.

 

[Sam Trenholme]

As a practical matter, for my particular setup, I'm not losing anything downgrading to 16/44.1. I imported one of my 24-bit tracks in to my computer and measured the noise level of its silent parts: While it sounded as quiet as a church mouse to my ears, the noise was about -80db below peak, which is a good deal more noisy than the noise floor of 16-bit.

The only time I get a better signal-to-noise ratio in the DP-32 is when I ran my beautiful sounding but noisy string synthesizer through Tascam’s built-in noise supressor. That did make the track have a 24-bit quiet noise floor — but I could get the same effect in post-processing after recording that noise box in 16-bit.

One thing people forget is how amazingly good 16/44.1 digital sounds. There is a reason, throughout the 1980s, anyone who could paid more than a house cost to get a digital multitrack with 16/44.1 sound. In 1985, a Sony PCM-3324 16-bit (at either 44.1 or 48khz) 24-track would set you back $133,600: That’s $290,178.95 in 2015 dollars. Even at that price, there were 36 3324s deployed in the US at the beginning of 1985. (Source: Billboard magazine, January 26, 1985)

 

[eric_the_b]

I have discovered that if you have a song full of "pops and cracks" use the COPY facility in the SONG menu. It duplicates the song but without the Pops and Crackles!! If you try putting some effects on the final master, the "pops and cracks"return! SO DONT!

 

[Dennis FMRJE]

Sam, just replying to your technological revolution post in the digital realm and the low cost it has achieved. I agree the cost change and recording fidelity is great even at 16bit/44.1/48k compared to analog recording quality. It is amazing that 24bit has 65k more resolution than 16bit. Since Tascam has moved on from DP24/32 with CD drive and midi perhaps the pop/spike issue will remain. Hopefully when Roundhill get his DP back from Tascam with the pop/spike fix we will know the solution.

 

[Gravity Jim]

Does everyone who is experiencing this problem have their DP unit connected to a computer or other digital audio device? Just curious. If any of you are having the problem with the DP not connected to any other digital device, please post.

 

[Roundhill]

Mine is not connected to any other digital device. This is a 24 bit recording issue that hopefully can be fixed. My DP-24 has been at TASCAM for over three weeks now, I have heard nothing yet.

 

[Gravity Jim]

Well, "a 24-bit recording issue" isn't any kind of understanding of the problem. If you blow a breaker everytime you make breakfast, saying "it's a toasted bread problem" isn't the answer. I just got interested in what's going on, and asked my question to rule out some basic reasons for this kind of noise.