Dynamic mic connected to Line input rather than Mic?

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mgray

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I have an SM58 and a Boss Micro BR(portable 4track). For this question I'm using the mic(with pop shield removed) to record a Vox AC-30.

I find that if I connect the SM58 to the BR Boss and select EXT(external mic) option for my input connection, I can hear clipping, even if I set the sensitivity to the lowest(-15). I can hear the clipping even though the OVER(clip) indicator doesn't light up.

If I select LIN(line) as my input, and put the sensitivity to full maximum (+8) I don't hear any clipping, and the background noise is noticeably reduced. The signal is still pretty hot.

So I guess my questions are; Is it normal for a dynamic mic's signal to be high enough to connect to a line input? And is there anything bad about connecting like this?
 
The micro BR uses a mini stereo 1/8 line in jack and I think can use a TRS to XLR cable for regular mics
Are you using a TRS to XLR cable?
Got another mic to test if mic is bad, Why no wind screen on it?

Switching from line (-10db according to specs) and "mic" (-40db) won't hurt the mic but usually line level would not give you enough gain.
 
Nope Im wrong the BR 600 can use a regular mic
micro BR needs a stereo mic
 
No, it's not normal. I suspect it must be a line/mic input. There's no way you should be getting a useable signal via a line in with no preamp.
 
It's possible to not need any gain added with mics on loud/close sources. It's a bit odd that your recorder isn't indicating the clipping, but yes it is possible to have enough level w/o 'a preamp' (or too much with one) depending on the combinations.
 
Sorry guys, I should have given more info.

Yes the Boss Micro BR input jack is a mini stereo 1/8 line in. I use a XLR to mono 1/4 with a 1/4 mono to 1/8 stereo adapter. From within the Micro BR menu I can select EXTERNAL MIC input or LINE input. But they both come from the same jack.

When I select the EXTERNAL MIC input, background noise is considerably noticeable vs the LINE input where background noise is almost non existent.

When I'm recording at the volume I do(mic is about 8inches slightly off center of speaker) I need to turn the sensitivity on the EXTERNAL MIC down as far as it will go(-15db). And like I said, even tho the CLIP indicator no longer lights, I can still hear something. Like a high sibilance clip/sizzle at times.

Selecting LINE input and setting the sensitivity to max(+8db) not only does the CLIP indicator still not show, but I dont hear any distortion and background noise is still very low. The overall volume level is lower than when selecting EXTERNAL MIC, but it's still plenty strong. And the amp(AC30) is only about 1/2 power on the pre and power sections.

I'll try to get a clip uploaded showing both inputs.

Is it common to be able to hear clipping/distortion on digital gear even if the clip indicator doesn't light?

Thanks
 
If anything 'red is soemtimes set a little below actual overload. And at that distance the level shouldn't be out of range.
'high sibilance clip/sizzle' ..? Wondering if this is the sound of clipping.
 
mgray said:
Sorry guys, I should have given more info.

Yes the Boss Micro BR input jack is a mini stereo 1/8 line in. I use a XLR to mono 1/4 with a 1/4 mono to 1/8 stereo adapter. From within the Micro BR menu I can select EXTERNAL MIC input or LINE input. But they both come from the same jack.

When I select the EXTERNAL MIC input, background noise is considerably noticeable vs the LINE input where background noise is almost non existent.

When I'm recording at the volume I do(mic is about 8inches slightly off center of speaker) I need to turn the sensitivity on the EXTERNAL MIC down as far as it will go(-15db). And like I said, even tho the CLIP indicator no longer lights, I can still hear something. Like a high sibilance clip/sizzle at times.

Selecting LINE input and setting the sensitivity to max(+8db) not only does the CLIP indicator still not show, but I dont hear any distortion and background noise is still very low. The overall volume level is lower than when selecting EXTERNAL MIC, but it's still plenty strong. And the amp(AC30) is only about 1/2 power on the pre and power sections.

I'll try to get a clip uploaded showing both inputs.

Is it common to be able to hear clipping/distortion on digital gear even if the clip indicator doesn't light?

Thanks
Click to expand...

The reason you hear noise on EXT MIC is because it is passing voltage through the line, as it thinks an electret mic is on the other end. It is unusual that it comes through without the preamp, but since it's a loud source, I am not all too surprised.
 
12milluz said:
The reason you hear noise on EXT MIC is because it is passing voltage through the line, as it thinks an electret mic is on the other end. ..
Click to expand...

What do you mean by that? 'Voltage through the line'?
 
What I'd recommend is run a few level test recordings. You could set your amp up clean as it will go, our sing a fairly consistent phrase, start at minimum mic level setting, then again up +6 or so and work your way up to where your are definitely lighting 'clip. This will give you a handle on how this thing behaves.
You want clean consistent source each time, the only (big) variable is record input setting. Clean guitar will be the peaky' example, voice the sustained examples.
That would go a long way to seeing what's really going on.
:)
 
12milluz said:
The reason you hear noise on EXT MIC is because it is passing voltage through the line, as it thinks an electret mic is on the other end. It is unusual that it comes through without the preamp, but since it's a loud source, I am not all too surprised.
Click to expand...

Thanks for the tip, but I'm pretty sure I have the power turned off. There is a setting which can give something like 2.5v, or nothing. I'm pretty sure it's turned off but I'll double check.

...still working on getting the clips
 
That is clipping right? It's not something wrong with the speaker that I'm only hearing when the mic is 3" from the speaker?
 
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