Need help resolving distortion on DATs

[AVATC]

Hello, all! I am a voice actor with a studio. I have never made DAT recordings; other clients are happy to receive files on line or on CD. I admit I still have much to learn about recording! I would be so grateful if any of you can discern whether I am doing something wrong in my process or setup.

I recently recorded an audiobook for a publisher who could only take the finished product on DAT or cassette. I sent my 10 hours of recordings on DAT to the publisher. The producer there said she could hear the tapes, but they sound distorted.

When I asked what kind of distortion are we talking about, I was told that it sounded like static. I am not dealing with a very technical group there and could not get a better answer. She said their DAT machine doesn't have the problem because they can play other tapes and not hear the distortion. When they have had this problem with DATs from other narrators, they have asked the narrator to master the recording to cassette. She thinks if she sends the DAT back to me, I won't hear the distortion on my machine. She thinks I recorded at a different frequency than they use. My machine defaults to 48kHz, but it automatically changes to 44.1kHz when I start recording from the computer. They use 44.1kHz when converting the DATs to cassette.

I bought a previously-owned Panasonic 3700 DAT recorder just for the purpose of working with this client. I also installed a Delta DIO 2496 sound card in my computer to connect to the 3700. I use Cool Edit Pro to edit all of my recordings.

I'm changed the output in Cool Edit to the s/pdif port of my Delta card, pressed record on the Panasonic and play within Cool Edit to transfer the recordings in real time (ugh!) from my computer to the DATs. I listened to the tapes at various random points as I rewound them, and they sounded good to me.

If I turn the volume on the DAT recorder up to full blast, I can hear a slight buzzing in the background during the pauses in narration. I can also hear this buzzing when listening in the headphones, which are connected to the built-in soundcard in my Sony Vaio computer. I'm wondering if the 2 soundcards are causing interference with each other. I don't recall hearing this slight buzzing (which is more evident when I move the mouse) when I just had the one soundcard. It seemed to start when the 2nd one was installed. I don't know if this buzzing is what the producer is talking about or something else entirely.

Any advice or suggestions? I need to solve this problem as I haven't gotten paid for the last book but already have a commitment with this publisher for the next book.

Thanks so much for your help!

Karen

 

[Blue Bear Sound]

There are a number of possibilities.

1) It's unlikely that they're playing back your DAT with the wrong bit-size or sample rate - except for the Tascam HR-45, all DAT's are 16-bit. And if they were somehow able to for the DAT to use the wrong sample rate, the only result would be a change of pitch.

2) Conceivably, there could be a problem with s/w at your end, but if you're not hearing this static when you playback on your DAT machine, then that isn't likely either.

3) The humming you may be hearing from your soundcard's is likely only on the monitoring path, and not in your recording signal chain, so I doubt that's the issue. (As far as that problem is concerned, you may have a ground loop in your monitoring chain - causing the buzz -- that's a whole separate issue, though)

4) Based on what you've described, the only thing I can think of is that there's alignment incompatibility between your machine and their's. DAT machine can get fussy about playback on different machines, and although each machine may be within the alignment tolerances - if one machine is off a little on the plus side, anf the other a little on the minus side, the alignment margin between the two machines becomes pretty wide - possibly causing the playback artifacts you've mentioned.

You can take your unit in and get it checked, and ask them to have their gear checked as well - providing the DAT tape to the tech also so that they can hear the issue. Mind you, if they do change the alignment, you risk having problems with tapes previously recorded using the prior alignment!

The best solution would be to convince them to get a CD-R drive and provide the material on CD.... DAT is a pretty dated format by now!

 

[maestro_dmc]

If I turn the volume on the DAT recorder up to full blast, I can hear a slight buzzing in the background during the pauses in narration. I can also hear this buzzing when listening in the headphones, which are connected to the built-in soundcard in my Sony Vaio computer. I'm wondering if the 2 soundcards are causing interference with each other. I don't recall hearing this slight buzzing (which is more evident when I move the mouse) when I just had the one soundcard. It seemed to start when the 2nd one was installed. I don't know if this buzzing is what the producer is talking about or something else entirely.
Karen

This sounds familiar! I have a Delta1010 and the Built in Sound Max card that came on the p4 motherboard. I noticed the aux in was picking up the sound of the hard drive when I moved the mouse, so I muted it.
Try going into the volume control for the Standard soundcard, and muting everything you are not using, CD, Aux in, Line in, Etc. and see if the buzz disappears. Try this while listening to the buzz, not before you put the headphones on, so you can be sure that what you're doing is working and not something else.

Can you ask the producer if the static was during spoken parts or between them? That's not too technical for them I hope.

Another thought, : Did you get a cable specifically designed for Spdif, or just a standard RCA Male to Male? I don't know if this would make a difference with "static" or not , just a thought.

 

[AVATC]

Hi, everybody! I've been so busy that I haven't gotten back here to thank you all for your kind advice and update you on the progress on this problem.

Maestro_dmc -- THANK YOU, THANK YOU for directing me to mute the outputs of the other devices! The buzz is GONE!! Yeeaaahhh!!!

It had been driving me CRAZY when I listened to the playback, and I knew it started when I put that second card in the machine. I thought I had something mis-configured, so I am very grateful for you, especially since this was a very simple solution!

UNFORTUNATELY, the buzz was only bothering me. While I could hear it on the DAT if I turned the volume way up, it is not the distortion that the producer is talking about.

The producer at the publishing house sent me a cassette with the distortion on it. You can hear my voice for a few seconds, but then you hear a sound like the machine eating the tape....or when you tune an analog radio and can't get the signal clear. It alternates between clear voice and the distortion with no discernable pattern. Some of the louder parts sound just fine, where the quieter parts have distortion.

I've read that recording past 0 on the DAT can cause distortion. Does that sound like a "record past 0" problem to you?


Blue Bear Sound -- It's interesting you specifically mention Tascam. The producer has a Tascam, but I don't know what model machine they have. I have a Panasonic SV-3700. From what you know about Tascam bit rate problems, could that have caused the symptoms I described above?

As you can tell from my comments to Maestro, you were right about the buzz being on the monitoring path.

The producer told me that they have had this problem with one other narrator, which makes me think the problem is their machine, not mine. The solution in that case was for that person to master to cassette. (shudder)

I gave the producer all of this information, and she planned to send her machine for service to the same facility that I am using. Hopefully, if the machines are side by side, they can tell us what is going on. I also gave them the cassette that she made for me where the distortion is evident.

I couldn't agree with you more about CDs! I provide my finished work on CDs or on-line to all of my other customers. This publisher only uses DAT or cassette. Since I had neither machine, I couldn't bring myself to go back to 1960s technology and buy cassette. I bought the DAT recorder just to work with this one customer.

I have subtly suggested more than once that they get a CD reader; as I'm still talking about this DAT distortion issue, you can see that hasn't happened!


Thanks again for your help, and keep those cards and letters coming!


Karen Commins
http://www.AVOICEAboveTheCrowd.com
"STAR quality work performed within your budget!"

 

[Blue Bear Sound]

A misalignment problem between the 2 machines could definitely cause issues such as static bursts, digital hash, or other digital artifacts (clicks/pops/etc)...

And it could be that both your machines are within tolerances, but the issue is that they are on opposite ends of the tolerance specturm with respect to each other, and so between the two specific machines, they are way out of tolerance figures resulting in artifcats

This is only speculation on my part though... but since neither of you experience issues on your own machines, only when you "swap tapes", this suggests inter-machine incompatibility rather than actual issues without either machine.

You could experiment with different tape brands, some may be more compatible with both machines than others... or you could bring them to the shop and have them more closely aligned (but be warned that you may be changing the alignment so much that your existing tapes would no longer play properly!) Tough call... sounds like the perfect excuse to get them to upgrade to CD!!!


Incidently -- I heard some of your demo clips -- it may be the MP3 encoding, but you do have sibilance issues and the occasional phase-related flanging in quite a number of those clips. You may want to check your mic placement and room acoustics of the area you do your voiceover work in.

 

[AVATC]

Thanks for the quick replies and additional information!

c7sus -- My Focusrite Voicemaster has a compressor and noise-reducing expander. I'm not sitting in front of it at the moment, so I can't say how it is set. However, I *think* I've been using only the noise-reducing expander without the compressor.

Instead of recording in a closet full of clothes (which I used to do), I converted a small (maybe 5'x5') walk-in closet for my recording booth. The walls are covered with Auralex studio foam, and I think the sound is pretty dead when I am in there. I have a Neumann TLM 103 mic on a broadcast arm, and I usually have the bottom of the mic about eye level so that I am speaking below it.


Blue Bear Sound -- I understand about sibilance and have been changing the settings on my Voicemaster over time to reduce it. However, I confess I have no idea what phase-related flanging is -- it sounds like some horrible disease! What is that, and what do you recommend to fix it?


Thank you all for generously sharing your knowledge with me! Not only are you helping me with my original problem, but you're providing great info that will help me improve my recordings. I really appreciate it!

Karen Commins
http://www.AVOICEAboveTheCrowd.com
"STAR quality work performed within your budget!"

 

[Blue Bear Sound]

Both issues (sibilance & flanging due to close-reflections interfering with the direct sound of your voice into the mic) are related to mic placement.

To minimize sibilance, aim the mic slightly below your mouth, and reduce the distance you speak from the mic.

The flanging/phasy sound occurs when sound is reflected off nearby surfaces and reaches the mic slightly behind (in time, because it's bouncing) the direct sound of your voice.

Since you say you walls are covered with Auralex, it's more likely that you're getting reflections off the table/stand you place your papers on, or even from the papers themselves. You simply have to orient everything so that reflected sound bounces away from the mic, and not towards it.

For example, angling the paper/stand with a sharper slope means the reflections will not bounce direct back to the mic, but slightly below it and therefore minimize the issue.

It doesn't happen in all your clips - so I'm guessing you're not always orienting yourself in the same position.

 

[TexRoadkill]

Thanks for the quick replies and additional information!

c7sus -- My Focusrite Voicemaster has a compressor and noise-reducing expander. I'm not sitting in front of it at the moment, so I can't say how it is set. However, I *think* I've been using only the noise-reducing expander without the compressor.

A noise reducing expander will boost your signal on peaks. If you are trying to avoid clipping then you want to use compression which will reduce your peaks.

The purpose of the expander is if you have a low level signal that is very close in volume to some background noise the expander will wait until a sound jumps above the bg noise (threshold) then it will raise up the volume. Depending on how you have that set it could be causing some weird stuff to happen.

 

[Blue Bear Sound]

Bruce...... you can get phase problems from the source bouncing off papers??

Sure... depending on how the talent holds the sheet, some sound can be reflected back up to the mic, causing this hollowish, phasey-kinda sound (due to comb-filtering effects of early reflections!)

BTW, what's IHNFI???