background hum problem -Sound Forge - PC - MAGIX Community Forums Archive

Subject:background hum problem Posted by: keether Date:3/16/2003 3:36:05 PM Hi. I use Sound Forge Studio to turn precious old vinyl records and cassette tapes into more permanent CDs. A problem is the background hum, which shows up on the digital screen as a "fuzzy dowel" core of each track. Even when there's no music, this "core" hums. Tracks obtained from commercial CDs have only a thin line there, and no sound. How can I cut down or eliminate this background hum?
Subject:RE: background hum problem Reply by: musicvid10 Date:3/16/2003 7:33:25 PM Well, one problem is with the magnetic cartridge (and tape heads), which pick up 60hz hum from their surroundings. Another factor is ground loops. Here is a whole list of suggestions, some of which will help, some not depending on your situation. 1. Make sure the phono, receiver/amp, cassette are all plugged into the same circuit. Check the integrity of the outlet with one of those 3 prong led testers from Home Depot, etc. If the power cord on the phono is not polarized, reverse it to see if it makes the hum worse or better. 2. Use as short a length of audio cable as possible between the phono and amp. Make sure it is good quality shielded coax. Some phonos have a place for separate ground wire, but this often has no effect on hum. 3. Again, use as short a length of coax as possible between the line out of the amp and the line in on your sound card. Make sure the computer is plugged into the same leg (power circuit) as the phono and amp. This is IMPORTANT. 4. When you are sure there are no ground current problems, you can do a ground lift to eliminate ground loop hum. This involves using direct boxes and a separate preamp, or disconnecting the shields from the connector on the cable that plugs into your computer. I recommend you have an audio technician do this if you are unfamiliar/uncomfortable with the concept. 5. As a last resort, you can dip the equalizer at 60hz to suppress the fundamental. Since AC hum is not clean, this will do nothing for the overtone interference. You can search the net for "ground loop" for more detailed information. I actually have about 50 ft. between my audio equipment and computer, but use direct boxes, XLR cable, a standalone mixer, and get very little hum when recording from vinyl. However, I realize very few home audio consumers have this kind of stuff available.
Subject:RE: background hum problem Reply by: ATP Date:3/17/2003 12:25:18 PM the above solution is good for getting your source input as clean as possible. if you find there is still noise on your recording there are a few noise reduction plugins available you can use. Sonic Foundry has a plugin called Noise Reduction which works pretty effectively most of the time. check out more info here : http://www.sonicfoundry.com/Products/showproduct.asp?PID=14

Well, one problem is with the magnetic cartridge (and tape heads), which pick up 60hz hum from their surroundings. Another factor is ground loops. Here is a whole list of suggestions, some of which will help, some not depending on your situation.

1. Make sure the phono, receiver/amp, cassette are all plugged into the same circuit. Check the integrity of the outlet with one of those 3 prong led testers from Home Depot, etc. If the power cord on the phono is not polarized, reverse it to see if it makes the hum worse or better.

2. Use as short a length of audio cable as possible between the phono and amp. Make sure it is good quality shielded coax. Some phonos have a place for separate ground wire, but this often has no effect on hum.

3. Again, use as short a length of coax as possible between the line out of the amp and the line in on your sound card. Make sure the computer is plugged into the same leg (power circuit) as the phono and amp. This is IMPORTANT.

4. When you are sure there are no ground current problems, you can do a ground lift to eliminate ground loop hum. This involves using direct boxes and a separate preamp, or disconnecting the shields from the connector on the cable that plugs into your computer. I recommend you have an audio technician do this if you are unfamiliar/uncomfortable with the concept.

5. As a last resort, you can dip the equalizer at 60hz to suppress the fundamental. Since AC hum is not clean, this will do nothing for the overtone interference. You can search the net for "ground loop" for more detailed information.

I actually have about 50 ft. between my audio equipment and computer, but use direct boxes, XLR cable, a standalone mixer, and get very little hum when recording from vinyl. However, I realize very few home audio consumers have this kind of stuff available.