Subject:hum on recording ?? help please !!

Posted by: woodster

Date:7/20/2004 5:23:48 AM

Hi, I am not very technically minded, so could be doing something stupid here, but . . . I am trying to record from an external device [tape deck] into SF and am getting a constant high pitched hum through the entire track?! I have tried different inputs - line in and mic, also different external sources - no matter what I do I am getting the same results?!

Only last week I did it without any problem - no interference, but now it just won't have it !! I have also tried a different internal recording programme, nothing makes any difference ??? Could there be a problem with the sound card or something like that ?? I have tried everything I can think of . . . so any suggestions would be greatly appreciated.

Thanks Laura :)

Subject:RE: hum on recording ?? help please !!

Reply by: Hummingbird

Date:7/20/2004 6:17:47 AM

Laura, the first thing I would check is the cord from your tape recorder to the sound card. Sounds like a possible break in the ground wire, though your description of a "high pitched" hum doesn't quite fit. Also, the line out of the recorder should not be sent to the MIC input of your card. You might check the mixer controls on your sound card to be sure the gain is not set too high.
I hope somebody else can assist you if these preliminary checks are not the problem. Good luck.

Hummingbird

Subject:RE: hum on recording ?? help please !!

Reply by: woodster

Date:7/20/2004 10:48:30 AM

Thanks Hummingbird :-)

Sadly though this has not cured the problem. I have tried different wiring and different inputs, messed around with the gain too, nothing seems to have made any difference. Even when I unplug all wires from the sound card you can still see the interference registering on the record monitors ??? The only thing that makes that go is to select 'wave' as the record preference - but . . . I don't know how to make SF recognise play-back from an external tape deck as a 'wave' ???

Thanks for trying though - I appreciate it :-)

Subject:RE: hum on recording ?? help please !!

Reply by: Chienworks

Date:7/20/2004 11:34:29 AM

Just for the heck of it, you might want to try uninstalling the sound card and reinstalling it. You won't even have to open the case. Under Start -> Settings -> Control Panel -> System -> Hardware -> Device Manager, you can find the sound card drivers and delete them. Reboot and windows will reinstall the sound card. (Just to be safe, it would be a good idea to have the drivers lying around handy before you start, either the disc that came with the card/computer, or download them.) It should only take a few minutes, and then the sound card should be back to working in it's factory original condition.

Of course, this is assuming it's a software problem. If it's a hardware problem then this won't fix it.

Subject:RE: hum on recording ?? help please !!

Reply by: metrazol

Date:7/20/2004 11:36:36 AM

3 Possible Problems:

1.) 60 cycle hum is leaking in from you good ol' AC socket. This is where that ground wire comes in. It's...a pain, but easily filtered. So spectrum analysis, if there's a spike at 60hz, voila. Of course, other things can leak in through power supplies, try using batteries to isolate the deck. I'd horrify you with a recording of a dead input from my recorder running on batteries vs. AC, but I don't want to scare the children. (Massice wireless network, huge cable runs, and second rate electricians have sent me to batteries in my own studio!)

2.) Sound card is picking up interference from your machine, or it's just junk (a common problem). Hitting 'Prepare' should kill most of the interference, but not all, since SF can latch onto the input signal and you'll do pretty well... sometimes. This is fixed by well...hmm...new sound card, or a nice preamp that'll blow the interference out of the water, but signal to noise is always rough with consumer gear.

3.) Something odd is inserting the hum. This can be a tad trickier. It could be your processor or disk leaking in, similar to 2., but more into unshielded cable than the card itself. Again, ground is good.

There're a lot of relatively cheap little boxes that'll filter all of these, ground loop filters, etc. but $90 to maybe fix something isn't much fun. Oh, and they're usually all XLR to XLR for production mixing, so eh.

What frequency is the hum? Knowing that would help a ton.

Hummingbird is on the right track, so try his suggestions and get back to the boards.

Subject:RE: hum on recording ?? help please !!

Reply by: woodster

Date:7/20/2004 11:54:27 PM

Thanks everyone :-)
Ok this gives me something to be getting on with LOL !! I will start from the top and work my way down as they! Thanks again and I will let you know if I actually manage to get rid of it. At least I have some ideas now, which is way more than I had before I posted here - you guys rock :-)

Laura

Subject:RE: hum on recording ?? help please !!

Reply by: woodster

Date:7/21/2004 1:53:31 AM

Ok - an update. I have done my best to see what frequency the noise is on the spectrum analysis [but again I am not very good at it, so please bear with me] I have monitored the 'input' and it is showing -52dB @ 26Hz on the left channel and -59dB @ 27Hz on the right - if I change the input to Stereo Mix it goes to -47dB @27Hz on the left and -95dB @ 24Hz on the right - again if I change the input to Wave nothing registers ???

So, does this make any sense to anyone - cause all I know is there is noise LOL !!! You guys seem to know your way around this programme wayyyy better than a learner like me :-) The above is just a bunch of figures that means absolutely nothing to me - again THANKS!

Laura

Subject:RE: hum on recording ?? help please !!

Reply by: Chienworks

Date:7/21/2004 5:51:37 AM

Hmmm. That's probably not the noise you're seeing there. 27Hz is an extremely low note, about 3 octaves below the A below middle C. Many speakers won't even reproduce that note. You might feel it more than hear it. It's certainly not a "high pitch hum". This makes me think the problem is in the output of the sound card rather than the input.

Can you record a sample of what you're hearing and save it as a short (1 or 2 seconds is plenty) .wav file? If you email it to testbench@vegasusers.com i'll post it so we can all hear what's going on.

Subject:RE: hum on recording ?? help please !!

Reply by: heinz3110

Date:7/21/2004 5:52:52 AM

...Some more tips....tinkering time... :)

-Is it a built-on soundcard, i.e. integrated at the motherboard? If *not* then try swapping the soundcard in a different pci slot,further away from the videocard and other cards in your system.Might reduce some nasty interference.

-Some systemfans in your system might cause interference.try the same thing as described above but then to regards of the placemnet of system fans.Also,bundling en "re-routing" cables inside the system case might help a tad.

-as mentioned before,build in /and/or cheap sound cards don't have the best specs to do "proper enough"recordings.Upgrading to a better soundcard might do the trick.

-Re-routing external cables (between tapedeck and soundcard ) might improve s/n ratio too.Just move 'm around and see/hear if you notice the difference.

Succes,Gerard

Subject:RE: hum on recording ?? help please !!

Reply by: woodster

Date:7/21/2004 9:32:35 AM

Thanks for the input Heinz - unfortunately, yes it is built in :( not my puter and although my mate is willing to add a sound card for me it wasn't known when it was built that it would end up being used for music !!

I did think about the fan - so waited until morning and tried before the fan kicked in - same thing !!! I have also moved the tape deck - nothing seems to be working, or even making a difference. I have mailed a sample of this wonderful noise to Cheinworks who said something about posting it - that way we can all 'enjoy' it lol !!

Guess I will just keep trying and hoping. I am so new at this though that for all I know it could be something so simple . . . but, having said that I have already done so many diffrent things to try and stop it !!!

Thanks again. Oh, if I got an external USB soundcard - can I bypass the motherboard sound card ?? And do you think that could be an idea ??

Laura

Subject:RE: hum on recording ?? help please !!

Reply by: Chienworks

Date:7/21/2004 10:19:44 AM

Sample file is here: http://www.vegasusers.com/testbench/files/woodster-nasty_noise.wav

I don't see any noticeable hum in it at all. It looks like wideband noise typical of most low end soundcards. There is some DC offset, but not enough to generate a hum. From what i see here i think it's very likely that you aren't recording the hum at all, but it is merely being added somewhere during playback. Can you try playing one of the files you've recorded on a different computer? Or maybe you could burn a sample to CD and try playing it on a CD player (not the one in your computer).

We'll get this licked yet!

Subject:RE: hum on recording ?? help please !!

Reply by: Rednroll

Date:7/21/2004 10:40:21 AM

My spectral Analyzer shows a high peak happening around 8.5Khz and a smaller peak at 250Hz. Not sure where these are being generated from in your recording signal. Reading this really makes me laugh to myself after having to argue a point with a certain "pro" over in the Vegas forum, when I suggested getting a balanced I/O sound card over an unbalanced I/O sound card to avoid noise issues like this. I'll make that recommendation again. Look into getting a sound card that has "Balanced I/O". Your USB external sound card might fix your problem, if the noise is coming from internal noise within your PC, because you are moving the A/D converters further away from this noise. If the noise is coming from external to your PC or through a possible bad ground, then this will not fix your problem. Maybe a dual choice option. Look into purchasing an external USB sound card, that has "balanced I/O", rather than a consumer grade one that uses "unbalanced I/O".

Subject:RE: hum on recording ?? help please !!

Reply by: MJhig

Date:7/21/2004 12:09:00 PM

Disconnect everything from your soundcard (tapedeck including cables etc.) and record. Do you still get this noise?

This will narrow down the problem possibly eliminating the external devices and cables or if you don't have noise under this condition the problem is in the external audio chain.

MJ

Subject:RE: hum on recording ?? help please !!

Reply by: woodster

Date:7/21/2004 12:25:17 PM

Ok guys, this gives me some things to do !! Firstly I will burn a sample onto cd and try it out to see if the hum I can hear is still present - if it is then . . . ???
mjhig, I did try that and I only get the sound when I record from an external source - but it is only something that has happened now, before was never a problem !! I will look into the I/O balanced external USB sound card, as that has got to be better for what I need anyways - that is assuming I can cure my phantom noise !!!

Should SF recording monitors be showing a level before you start to record ?? I didn't think they should !!! Cause that to me is what I am hearing, possibley ?!?! and that is there no matter what, tape deck or not - but only hear it on external recording - I did record direct from cd and that was clean !!

Ok back to the drawing board LOL - *sigh*

Laura

Subject:RE: hum on recording ?? help please !!

Reply by: rraud

Date:7/21/2004 12:48:43 PM

The SF meters will indeed show the "noise floor" of the input stage or sound card without an input present. . depending on the resolution setting of the meters (right-click meter to change the scale)

Subject:RE: hum on recording ?? help please !!

Reply by: Rednroll

Date:7/21/2004 1:01:28 PM

Another thing I would check before investing in a new sound card is to open up the Windows mixer by double clicking on the speaker icon in your system tray. Select OPTIONS>PROPERTIES>RECORDING>OK. Be sure that ONLY the Line In is selected in the recording mixer section. Then try reducing the gain fader/slider for the Line IN. This recording has a high noise floor, usually contributed to a cheaper sound card, and having a high gain setting only increases this noise. Also, I have seen in the past where cheaper types of sound cards start to get feedback, although there isn't any feedback loops. Usually reducing the gain to something below a 1/2 volume settings fixes this problem. Ensuring that only the line in is selected for recording ensures that other sources aren't being added in with the Line In signal and adding additional unwanted noise. Also go into Sound Forge select PROPERTIES>WAVE. In the recording device selection, make sure your sound cards Line In driver is selected, instead of the Microsoft Sound Mapper.

Subject:RE: hum on recording ?? help please !!

Reply by: LightMfg

Date:7/21/2004 3:26:36 PM

As Rraud said, you will see some level(if you have "MONITOR" checked) indicating the noise floor of your sound card. the difference between what you see there with nothing playing and (for digital recorders) O dB or the top of the scale, the loudest sound you can record without distortion, is called "Signal to Noise ratio" commonly listed as "S/N" in equipment specs.
My Sound Blaster Live internal card usually shows up(and jiggles around) at about -50 or -60 or so, depending upon what is connected to the line input (usually a turntable phono pre-amp in my case). While this is only mediocre for a digital system ALMOST NO analog tape recorder, esecially a cassette, will achieve much better than 45 to 50 dB of S/N.
What this means is that unless the level that you are seeing on your meters is above, oh say, -35 or -40 or so you really shouldn't be hearing it at all, because, unless your tapes are exceptionally well recorded, the tape's noise will be louder than the sound card's noise.
Rednroll's suggestion makes ton of sense, it sounds like you may have a microphone ?? connected with it's volume turned up on the windoze volume control panel; and, if you are trying to listen as you record this is probably causing a "squealy" kind of feedback (you mentioned that this was "high-pitched hum").
The other possibilty, of course, is that you have a bad cable, with a broken ground or even worse a broken "hot" lead. I've generated all KINDS of noise using bad or improperly shielded cables with or even near computers.
If the noise is a kind of constant squeal, then it's probably some sort of feedback(but I would suspect feedback from a mic or external mixer before I replaced the sound card- OR do you have both the input and output of your sound card attached to the tape deck?? as this, too , can cause feedback if both are turned up in windoze' mixer...) ); if the noise has a kind of "rachety" quality to it, a high pitched but with a lot of other crap (clicks and such) then you have some sort of grounding or shielding problem and a good set of cables is cheaper than an HQ sound card...

Subject:RE: hum on recording ?? help please !!

Reply by: LightMfg

Date:7/21/2004 4:14:18 PM

By the way, if you are trying to transfer a cassette tape you may also be having a tape shell problem; many old cassettes "squeal" because the tape is stretched and wound badly inside the shell or the pressure pad is sticky.
If this appears to be the case (you should be able to hear this with headphones at the tape deck itself even if it is not connected to the computer while the tape is playing but this noise can be intermittant and may only start after the tape has played for 15 minutes or more) then you can usually get the tape to play at least once or twice by transferring the tape spools into a new shell - see my post in "RE: Remastering A 20 Year Old Cassette Tape"...

Subject:RE: hum on recording ?? help please !!

Reply by: MJhig

Date:7/21/2004 4:39:43 PM

Here's the key;

mjhig, I did try that and I only get the sound when I record from an external source

I would first look seriously at the external gear and cables and their routing including grounding. That includes which AC circuits you are plugged into. Change cables, be sure your of your settings on the external devices especially the gain staging. Check the same gear on another PC if possible.

Your soundcard is definitely not "pro" quality and there will be a noisefloor around -50 dB at best but with proper external gear, cabling and gain staging that can be insignificant in a recording.

You also may live in an area that has RFI or intermittent dirty power, in which case a new non-balanced soundcard would likely be a waste of money concerning eliminating the noise. That said, a shee shee poo poo, top of the line soundcard is only going to record the external noise better if the external gear problems are not solved.

Edited later;

I forgot to mention, your sample sounds like an impedance miss match, something like connecting to a boom box headphone out with the gain too high. You could save a lot of typing and guessing by stating exactly how and what you have connected.

The DC offset is the largest I've ever seen also, this is an area that someone like Red would be better discussing but I think external gear can introduce offsets if I remember correctly. I've received many recordings to mix and even done some myself on a goof with one of my PC's that has an onboard AC 97 soundcard and never seen offset like this, not to say this is the source of your noise though.

MJ

Subject:RE: hum on recording ?? help please !!

Reply by: woodster

Date:7/24/2004 1:57:18 AM

Ok guys, well thanks for all your help :-) The problem is now solved - it was the sound card had corrupted somehow - a new sound card and again perfect recording !!!

So thanks for all your input - I appreciated it

Laura

Subject:RE: hum on recording ?? help please !!

Reply by: Rednroll

Date:7/24/2004 7:03:59 AM

With the DC offset that MJ mentioned and the high pitch squeel, I'm willing to bet there was a failed capacitor on the sound card somewhere. Capacitors are there to help reject unwanted nearby sources of noise and to elliminate DC offset.