bad audio input.

Kent-Birge wrote on 11/11/2020, 6:04 PM

Bought a new computer, Lenovo ThinkCentre. Have used Magix or SoundForge for years with no problems. Now, as I try to connect my amp to the mic input I get a muddy, phased audio. The soundcard picks up signal from sources like YouTube and disc player OK but will not work well for the mic input. The output from the amp gives a good signal to the tapedeck, and to the speakers. Is the signal in need of tweaking? Have tried different internal settings also. What gives?

Comments

Former user wrote on 11/11/2020, 6:56 PM

Magix didn't make your computer. Why don't you post this on a Lenovo support forum?

Kent-Birge wrote on 11/11/2020, 7:36 PM

Will do.

emmrecs wrote on 11/12/2020, 4:11 AM

@Kent-Birge

In addition, I don't think you should be even attempting to connect my amp to the mic input. The difference in signal level between the output of your amp and what a mic would output can be extremely large! My suspicion is that your computer is "attempting", apparently without much success, to attenuate or compress the signal coming into the mc input socket.

HTH

Jeff

Kent-Birge wrote on 11/12/2020, 6:19 AM

That's where i've always connected it. Got any other connection advice?

emmrecs wrote on 11/12/2020, 7:42 AM

@Kent-Birge

Bearing in mind you say this is a new computer, I suspect your "old" one had a socket that was both line and mic in and it could automatically adjust to whichever signal level was presented to it. Clearly, your new one does not!

You need to find a method of attenuating the input signal so that it does not overload the mic input. Have a search for "in-line attenuator" and see what is shown, bearing in mind you need to be able to connect this between your amp and your computer so check carefully the actual connection plugs and sockets. Having never needed to do this particular level of attenuation it is impossible for me to advise exactly which level of attenuation you should be aiming for. But if you check the output level of whichever connection you are using on your amp and then have a look at Lenovo's specification for the input level to that mic socket, you need an attenuator that reduces by something very close to the difference between the two!

HTH

Jeff

rraud wrote on 11/12/2020, 10:26 AM

I too would surmise you are over-driving a mic input. Typically, mic level is -60dB, line level is usually -10dB unbalanced and +4dB balanced (nominal). I would recommend getting a USB interface that has a mic/line input
Otherwise, a simple 'L pad' attenuator can be made with two resistors and a 3.5mm TRS plug for a few dollars if one has soldering skills.

Kent-Birge wrote on 11/25/2020, 1:38 PM

OK. Finally got the sound to work. The soundcard that came with the computer was unable to handle the signal coming in and I now have an upgrade with a new sound card. What I learned from the tech that was here is that computers are notoriously low prioritized to handle sound coming in and more interested in sound going out. However, if you get problems like this, get a dedicated soundcard.