On Fri, 18 Jul 2014, Oon-Ee Ng wrote:
Hi, I'm running Arch Linux 64-bit with jack2. I have a USB UA-25EX to which I connect a Shure SM75. I don't do much recording, and at a very amateur level for various volunteer projects.
SM75? or SM57? Everything I look up on sm75 turns out to be an sm57... So a dynamic mic. (Phantom off)
The maximum volume I get from my Shure SM75 seems very low. The result of this is when I normalize I get fairly significant background hum. Increasing the UA-25EX's gain just causes peaking at louder volumes, so no solution there. This happens with both Audacity and Ardour, so should not be software-related. Any suggestions as to what I should investigate? A bad mic (I did check, its not a knock-off)? Electrical noise from my laptop (used to use a different laptop but from the same manufacturer, same results from both). Jack settings?
I get that you did not buy this mic, but that it is whatever is around. There are a number of mics that look like the sm57. The only shure mic with a 75 is the pe75 (looks sm58 - ish) If you have a shure PE75H, it is a high impedance mic (30k plus) and probably comes with an xlr to 1/4 inch cable. If so, try pluging into input 2 and setting high impedance (HI-Z). Note: on this mic pin 2 is not connected, so using an xlr to xlr cable will not work right. (there is a PE75L that is properly connected inside the mic)
Please note that whatever mic you have, (PE75 or SM57) it is designed for close mic work, not for area mic use.
You say the mic causes peaking at higher levels, yet I would suggest it needs to be almost to the top. The odd peak from touchong the mic or plosives is probably not a problem. (use the limiter provided - peak LED green) Use your ears above looking at flashing LEDs or even waveforms.
As you may have guessed... I am mostly guessing :) we need to know what you are recording... how far from the mic, what are the settings on the UA-25EX... all of these things. As you can tell it even matters what kind of cable and which input you are using.
-- Len Ovens www.ovenwerks.net _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
