attenuator pad. where to put it?

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punkrockdude
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attenuator pad. where to put it?

Post by punkrockdude » Mon Feb 14, 2005 7:27 am

Hi folks.

I have been thinking about where the optimal position of a attenuation adaptor is best placed. Connected to the mic or connected in mic pre.
I have a theory about it which might not be correct but it is as far as I can see/figure it (out).

1. If I put a 100dB adaptor on the microphone, then the signal will go from 100dB to 80dB (just a figure), and along the way the cable will pick up 40dB (once again, theory), then the SNR will be 40dB right?

2. But if I put the attenuator at the mic pre, the mic will send 100dB and pick up 40dB of noise along the cable, then the SNR will be 60dB, right?

So, am I right to say that the best place to put the attenuator is at the mic pre?

Best Regards
Rickard Gerthsson

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Re: attenuator pad. where to put it?

Post by The Real MC » Mon Feb 14, 2005 7:57 am

Attenuate at the preamp. The noise will also be attenuated xdB, therefore improving the s/n ratio.

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Re: attenuator pad. where to put it?

Post by bigtoe » Mon Feb 14, 2005 8:13 am

punkrockdude wrote:Hi folks.

I have been thinking about where the optimal position of a attenuation adaptor is best placed. Connected to the mic or connected in mic pre.
I have a theory about it which might not be correct but it is as far as I can see/figure it (out).

1. If I put a 100dB adaptor on the microphone, then the signal will go from 100dB to 80dB (just a figure), and along the way the cable will pick up 40dB (once again, theory), then the SNR will be 40dB right?

2. But if I put the attenuator at the mic pre, the mic will send 100dB and pick up 40dB of noise along the cable, then the SNR will be 60dB, right?

So, am I right to say that the best place to put the attenuator is at the mic pre?

Best Regards
Rickard Gerthsson
"along the way the cable will pick up 40dB (once again, theory)"

i'm not following...but unusual though...

if your mic is 'hot '- pad the mic.

if you're pre is overloading - pad the pre.

doth that help? it sem like you're talking about gain staging...the likes of which i've never seen though...very well could be me...

Mike

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Re: attenuator pad. where to put it?

Post by punkrockdude » Mon Feb 14, 2005 9:01 am

Thanks alot for the help both of you (bigtoe and The Real MC). Bigtoe, I am sorry, but I can't explain it better (I think). But let me try:

1. No pad connected directly to the mic: 80dB from mic (100dB attenuated down to 80dB) which will be mix with 40dB noise which the cable will pick up along the way = 80bB - 40dB = 40bB SNR

2. Pad at the mic pre: 100dB from the mic which will be blended with 40dB noise picked up by the cable = 100dB - 40dB = 60dB which will later on be attenuated with 20dB, but will attenuate "both" signals 20dB so the SNR should be same (60dB)

Maybe this is not better explained the the first try I did. And my calculations may not apply in real life.

Best Regards
Rickard Gerthsson

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Re: attenuator pad. where to put it?

Post by KennyLusk » Mon Feb 14, 2005 9:06 am

There are other things to consider also. Padding the mic can be used as an effect, especially to throw off proximity issues in a mix for background vox or something you want to push "back" in the field of depth. Oddly enough, it can also double as a natural noise gate, can change the tone of an instrument (especially vocals) and can decrease the need for compression in some cases. Using a -10dB or -20dB mic pad can be a different way of accomplishing some common effects that require processing through a relatively long circuit that may add a color you don't want at that particular time. Effect.

You can even stack mic pads on top of each other. Like the 010dB pads that come with the MK-012 can be stacked for some crazy mic attenuation.

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Re: attenuator pad. where to put it?

Post by bigtoe » Mon Feb 14, 2005 10:09 am

hey... i think i get the gist of what yer talking about...somewhat.

"Pad at the mic pre: 100dB from the mic which will be blended with 40dB noise picked up by the cable = 100dB - 40dB = 60dB which will later on be attenuated with 20dB, but will attenuate "both" signals 20dB so the SNR should be same (60dB) "

yeah. if i'm reading you right. the ratio stays the same...however since you're talking about the mic pre - you have a new S/N ratio to deal with...that of the mic pre.

"And my calculations may not apply in real life."

i hear you there, buddy!

Mike

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Re: attenuator pad. where to put it?

Post by vvv » Mon Feb 14, 2005 10:48 am

I just want to note that you are very intelligent to post your question here at the TapeOp forum because asking "where to put it?" on some other boards would undoutedly result in some less than helpfull and not funny responses, kind of like this one.
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Re: attenuator pad. where to put it?

Post by punkrockdude » Mon Feb 14, 2005 1:52 pm

To VVV:
When you mention it, it sounds funny. Damn, why didn't I even think of that when I wrote it :)

So, what would you guys say? Put the ATTENUATOR directly after the mic or before the pre amp?

Best Regards
Rickard Gerthsson

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Re: attenuator pad. where to put it?

Post by KennyLusk » Mon Feb 14, 2005 2:23 pm

LOL. punkrock, it sounds like you might want to read all the replies again. Ultimately you make the decision where to put the pad and there's enough information in these replies for you to make that decision. It's your decision, not someone else's.

But if you insist on someone telling you then I opt to take advantage of vvv's post and pick door number 3. :lol:

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Re: attenuator pad. where to put it?

Post by punkrockdude » Mon Feb 14, 2005 2:29 pm

KennyLusk wrote:LOL. punkrock, it sounds like you might want to read all the replies again. Ultimately you make the decision where to put the pad and there's enough information in these replies for you to make that decision. It's your decision, not someone else's.

But if you insist on someone telling you then I opt to take advantage of vvv's post and pick door number 3. :lol:
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Re: attenuator pad. where to put it?

Post by bigtoe » Tue Feb 15, 2005 5:27 am

'So, what would you guys say? Put the ATTENUATOR directly after the mic or before the pre amp?'

:)

i stick it after the mic when i have an inline one which hasn't been a long time...so i could be wrong!

Mike

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Re: attenuator pad. where to put it?

Post by punkrockdude » Tue Feb 15, 2005 6:04 am

Bigtoe: Thanks for your thoughts about the matter.

Why I still asked about what to do even though The Real MC had replied, was becuase he didn't tell me if it did keep the noise down. I wanted some more thoughts on it, for example someone to better explain if it might had been correct with my calculations.

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Re: attenuator pad. where to put it?

Post by Mark Alan Miller » Tue Feb 15, 2005 6:25 am

KennyLusk wrote:Padding the mic can be used as an effect, especially to throw off proximity issues in a mix for background vox or something you want to push "back" in the field of depth. Oddly enough, it can also double as a natural noise gate, can change the tone of an instrument (especially vocals) and can decrease the need for compression in some cases.
Some of this isn't making sense to me, particularly the bits about "push(ing) 'back' in the field of depth" and "a natural noise gate".
I do understand the bit about changing the tone, but if a pad that is merely resistance in series is used, the tone shouldn't be changed at all (discounting the change in impedance matching/loading of the mic and pre.) Resistors also add noise, although not much.
Decerasing the need for compression also confuses me, as any circuit that would lower the dynamic range of a signal must be doind something else funny, like resonating.
More clarification, please.
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