[PLUG] Microphones

M. Edward (Ed) Borasky znmeb at cesmail.net
Mon Oct 23 16:41:30 UTC 2006


John Jason Jordan wrote:
> On Sun, 22 Oct 2006 23:42:07 -0700
>
>   
>>> John Jason Jordan wrote:
>>>       
>>>> I need a microphone to record speech clips in Phonetics class. 
>>>> I bought one today at Radio Shack, but will have to take it back
>>>> because it doesn't put out enough juice to make a loud enough recording
>>>> on my Compaq R3240 notebook with Ubuntu amd-64 Dapper. I cranked all
>>>> the sliders to the max, but it was just not loud enough. 
>>>>         
>
>   
>> Galen Seitz wrote:
>>     
>>> I don't know much about laptop sound systems, but I wanted to point 
>>> out a couple of potential problems.  1. Was the mic connected to the 
>>> wrong input(line versus mic)?  2. Does your laptop even have a mic 
>>> input?  If not, output level of a normal microphone is likely to be 
>>> too low.
>>>       
>
> "M. Edward (Ed) Borasky" <znmeb at cesmail.net> dijo:
>   
>> Some things to check:
>> 1. Open a terminal in "root" mode and do "lspci". That will tell you 
>> what sort of sound card you have.
>>     
>
> It says:
> 0000:00:06.0 Multimedia audio controller: nVidia Corporation nForce3
> Audio (rev a2)
>
>   
>> 2. Make sure the module for that sound card is compiled and loaded. Do 
>> an "lsmod" to see if it's there.
>>     
>
> Well, I already knew it was NVidia nforce 3 from the GUI Device
> Manager, but neither Device Manager nor lspci tells me what the name of
> the module is. Just "lsmod" gives me a long list, several of which
> start with "snd-." But I don't think this is the problem -- the sound
> *does* work. Playback is fine. It even records. It's just that the
> microphones I have tried are apparently not putting out enough juice.
>
>   
>> 3. Use the "alsamixer" console app. Make sure the little "M" is turned 
>> off on the microphone. The volume settings should be out of the red 
>> zone; I generally bring them up until they turn red, then down again. On 
>> my sound card that registers about 71.
>>     
>
> I opened alsamixer, but a lot of it is mysterious, and the man page
> doesn't always help. The first problem is that I don't have any idea
> what some of the controls are, that is, what they are supposed to do.
> For example, the first item is Master and underneath it shows 100<>100,
> and the color bar above is white, green and red, in approximately equal
> proportions. The man page doesn't tell me what the function of master
> is, or what the colors mean, or what the 100<>100 means. The next item
> is Master Mono, which appears to be Off, but again, I have no idea how
> it is different from Master, or even what Master does. Moving along,
> Line Jack Sense appears to be Off also, but I remember turning it on in
> the Gnome panel applet, and it definitely is on, that is, the speakers
> do go silent when I plug in headphones.
>
> But in spite of my kvetching above, alsamixer does seem to have done
> something for me. Arrow-keying along the different controls I got to
> Mic and Mic Boost. Mic was already set to 100<>100 (which I am guessing
> means the max input from left and right channels), but Mic Boost was
> "MM." I changed "MM" to "OO" and then tried the two microphones I have
> (one crappy old ancient thing and one brand new high quality Radio
> Shack one), and both now record at acceptable levels. Well, "almost
> acceptable," because I still need the Mic setting in Audacity set to
> the max. I worry that setting all these controls to the max is inducing
> distortion. Plus, I had to hold the Radio Shack microphone right in
> front of my mouth, which is not really suitable for recording a
> linguistics informant.
>
>   
>> 4. Install a graphic recording package and use the VU meters in it to 
>> see if you're getting a signal. I've forgotten which ones are the best 
>> -- what little mike work I do these days is Skype with a gamers USB 
>> headset with built in mike and on Windows. :)
>>     
>
> As noted, I'm definitely getting a signal. Just not enough signal. And
> Audacity does have VU meters, which are dancing back and forth as I
> speak into the microphone. Plus, Audacity displays the waveform, which
> also shows the sound level.
>
> I think I am going to try a microphone designed for computers. After
> googling a bit, the Labtec 524 sounds like a good one to try. I think
> the Radio Shack microphone is designed for a PA system, which is
> expecting a different level. Like I'm plugging a magnetic phono
> cartridge into the Aux input on a stereo. I just wish I knew what the
> microphone input on this computer was expecting so I could buy a
> microphone matching those specs.
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>   
I have a wonderful Plantronics USB "Gamer Headset" -- I forget the model 
but I got it at CompUSA. You'll have to do some kernel-level juggling to 
get the devices right, but I think it would be a good one for this. But 
you're right -- get a microphone specifically designed for computers. 
Radio Shack should have them, and CompUSA has boatloads of them.



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