Remote recording problem...

[The Monk]

I do onsite/remote recording, but am fairly new to it.
I recently upgraded my hardware to an iMac G5 and a PreSonus FIREPOD. The first time I used this gear I got excellent results.
However, a second time, at the same location and same hardware, produced some transient but very serious problems which I'm hoping someone here might be able to shed some light on (and have possible solutions).

Since I don't believe I can upload the actual sound file (as MP3) here, I'l try to describe what happened.
Initially, the problem started as a steadily growing popping sound, like 'needle-popping' on a vinyl recording. It quickly grew in intensity to the degree that it began to 'shred' the audio across all seven recording channels/tracks. In the end, it became a garbled mess in which the vocal even somehow began to take on an fx quality (echo).

At the time this was happening, even though I was wearing headphones, I didn't hear this heavy distortion since I was monitoring the signal as it was going _into_the computer from the FIREPOD, rather than from the software (Cubase) itself.

And even more perplexing is that the problem came and went on its own, _without_ my quitting the software, let alone rebooting the computer.

For all the world this both sounded and acted like electrical interference, possibly through the power cord or somehow across the audio cables (though in that case I should have heard this in the headsets). So things seem to point to line interference at the computer end.

Has anyone else ever encountered this problem while recording? I realize remote recording is a very different kettle of fish from studio production, as the former has more variables than the latter (such as onsite poor wiring which may be susceptible to EMI and other negatives).

Thanks.

 

[FALKEN]

first you need to make sure that your recording software is NOT set to monitor. if it is not, then you need to call presonus.

 

[AGCurry]

If you can't reproduce the problem, it's unlikely that we'll be of any help.

 

[TimOBrien]

Yup, bad wiring is going to be a huge problem for you.

You should always set up with enough time to do some serious testing, and I'd be thinking REAL hard about ways to run everything off of batteries (if you need 110v, you'll have to get some good expensive inverters) just to take the problem out of the loop.

 

[The Monk]

Working further w/ the files the interference enters and exits twice, before disappearing altogether. This would indicate either EMI or RFI--and it's the second cause that i'm now seriously considering as the culprit, since my cell phone located near the computer received two calls (which I didn't hear because of headphones). There is also a hospital located across the street, which also has equipment capable of generating RFI.
At present I'm thinking now it was the cellphone. The first time I recorded at this same location everything went fine--and I'd received no phone calls. This time two calls came in roughly (as memory serves) syn-ing with the heavy static in the recordings.

Thanks for the replies. Next time I turn off the cell phone, and see what happens. If it doesn't happen any more, then this very much will point to it as cause. I'm coming across numerous reports of cell phone transmissions affecting nearby electronics, including computers.

The Monk

 

[Rag]

First thing I tell people who i'm recording is to turn all theirs phones off, even if they're on "silent" mode. Had to scrap far too many good takes because of them.

 

[Rstiltskin]

Just some ideas

Working further w/ the files the interference enters and exits twice, before disappearing altogether. This would indicate either EMI or RFI--and it's the second cause that i'm now seriously considering as the culprit, since my cell phone located near the computer received two calls (which I didn't hear because of headphones). There is also a hospital located across the street, which also has equipment capable of generating RFI.
At present I'm thinking now it was the cellphone. The first time I recorded at this same location everything went fine--and I'd received no phone calls. This time two calls came in roughly (as memory serves) syn-ing with the heavy static in the recordings.


you are working with computers and that means the problem could be almost anything. The iMac G5 is really nice.

1. Does apple have a knowledge base and does it have any entries in re digital recording. If so, you know its coming, read them.

2. Do you have the latest updates to the OS, the drivers, the software the outboard is dumping into?

3. Do you have more than 256meg ram? I reccomend 512. (no reason, just the more you have, the more room you have to swap stuff in and out. Digital recording is very sensitive to the processor haveing plenty of time to do everything it needs, has fast ram room for plenty of buffers, in and out)

4. The maker of your outboard equipment would be the one I would try to send a file to. You can burn it on a cd on the superdrive, then you (and they) will have an exacte copy of your file.

may well be your phone, tho. Try holding your phone up to a speaker phone(a few inches away) and try to call someone on the cellphone.

remember, outboard people will blame it on the computer, computer people will blame it on the outboard equipment, they will both blame it on the phone if you give them a chance. PM me if you still have a problem, I will try to help.

 

[The Monk]

First thing I tell people who i'm recording is to turn all theirs phones off, even if they're on "silent" mode. Had to scrap far too many good takes because of them.

Bear in mind most of the recordings I did came out fine, so it's not an issue w/ hardware or software at the recording end, as some here have helpfully suggested--I'm, so far as computers are concerned, an old hand, with an emphasis on 'old'--starting with an Apple IIc, back circa '84-85.
At that point, neither hardware or software was even glimpsing recording (other than pioneers working with MIDI).

It was an interference--most likely RFI involving a cell phone--while the software was automatically writing to the hard disk during the recording process. I don't imagine this is probably very good for that storage mechanism, but then it may be harmless.
But the recordings were ruined, and that's enough in itself.

Switch off the cell phones, recordists, is the lesson I've a bit painfully learned.

 

[SouthSIDE Glen]

Monk,

It sounds like you have it pretty well figured out with the timing of the phone calls to the interference. Based on the info given here, that sounds like a likely cause.

But I do want to, just for general edification, amplify for just a second a good point you brought up in passing; the nearby hospital. Medical centers with heavy medical imaging systems such as MRI machines can be major sources of EM pollution and RFI all over the spectrum, sometime at a distance of as much as a couple of miles. While I have not yet (knock wood) had an instance where they interfered with my studio or location recordings, I have had them cause major interference with 2-way radio communication and even a wireless microphone setup (in a non-recording situation at the time). There's not a whole lot one can necessarily do about it at the source end - one cannot go to the hospital and tell them to stop using their MRI machine , but it is something to be aware of when troubleshooting problems such as you desribe.

It can also be something important to consider when choosing a location for your studio. While being close to a hospital can be an advantage for when Ozzie Osborne ODs in your studio (j/k ), it can be a lousy choice for the reasons described above.

US$.02

G.

 

[FALKEN]

sucks about the recording. it happens though to all of us.

 

[Alexbt]

I get interference from my phone all the time through my headphones and speakers--even if I'm not receiving or making a call. I tend to turn it off if I'm recording or listening.