Mic pads — they all work the same, right?

[alexdingley]

This is sort of an idle curiosity that came to a head as I overheard someone speaking VERY confidently (and I think VERY incorrectly) this weekend.

I'm just curious if anyone else have ever noticed some engineers/musicians talking about using a pad on their mic "to protect the mic" when using it with high-SPL sources. I've always ignored it, but I was listening to someone talk about a recording of drums with their small-diaphragm condensers and how it was "so important to use the pad, to that you don't hurt the capsules when you put them up close to the drums."

...I'm pretty sure the above constitutes a complete misunderstanding of how a mic pad works, but I try to never be too sure of anything, so I wanted to put this question out there.

Aren't the pads JUST dampening the output voltage a bit, so you can goose-up the mic pre a little more (and get farther into the travel of the mic pre) to hopefully get away from the low (and potentially noisier) end of the mic pre potentiometer?.... or are there any "physical" mic pads that in some way change the way the diaphragm is ... yeah, I can't even finish this hypothetical because it doesn't even make sense, right? If anything "protected" the capsule, wouldn't it likely block or change the way the vibrations translate? There's nothing like that happening, right?

[kslight]

Yeah I don’t think a pad is there to protect the mic, my understanding is it’s to help avoid overloading the mic’s electronics and or reduce the output level for going into a preamp.

[markjazzbassist]

the sound waves will reach the mic capsule regardless of what is downstream electronically. it's physics.

[digitaldrummer]

yeah, only if the "pad" they are using is a sock. electrical pads are usually just resistors... after the capsule.

[Nick Sevilla]

A mic "pad" is only to reduce the voltage coming out of the microphone. It allows one to protect from excess voltages distorting the rest of the signal chain down the line. A good rule of thumb to follow is to implement the pad as close to the diaphragm as possible. If your mic has one, use that one. If you need more, put the smallest value that will get the job done right at the output of the microphone. Before the MASSIVE amplification of the mic preamp.

It does absolutely nothing to protect the diaphragm itself. That is done by either positioning the mic outside the main air burst of the instrument, by covering it with a "rat" which is that fluffy stuff you see mostly in outside film tapings, to reduce wind noise, or using things like a pop filter or other physical barrier between the diaphragm and the signal source.

One of my favorite drum overhead, and acoustic guitar recording mics, the AKG 451EB. R6, R7, R8 select the output padding of the mic, directly after the amplifier transistor T1, which is the output from the diaphragm:

https://www.gyraf.dk/schematics/AKG_C451EB.GIF

[floid]

As counterpoint, Scodiddly's simplified JFP has Scott Hampton's article fresh in my mind. In it he advocates for placing the pad after the preamp input transformer, "b/c transformer saturation can be cool and most mics are unlikely to cause huge amounts of saturation," or words to that effect. Which I think can be interpreted as waiting as late in the signal chain as possible to pad down the signal.

[Scodiddly]

One exception I can think of is that Beyer used to have a special windscreen for the early M88, for use on kick drum. That would account for a sort of "pad" as it did protect the diaphragm from the large amount of air movement that is possible in that application.

[Nick Sevilla]

As counterpoint, Scodiddly's simplified JFP has Scott Hampton's article fresh in my mind. In it he advocates for placing the pad after the preamp input transformer, "b/c transformer saturation can be cool and most mics are unlikely to cause huge amounts of saturation," or words to that effect. Which I think can be interpreted as waiting as late in the signal chain as possible to pad down the signal.

Well he really is advocating for distortion of the mic preamp transformer. Pads are designed to stop distortion from happening.

Saturation = Distortion.

[vvv]

As counterpoint, Scodiddly's simplified JFP has Scott Hampton's article fresh in my mind. In it he advocates for placing the pad after the preamp input transformer, "b/c transformer saturation can be cool and most mics are unlikely to cause huge amounts of saturation," or words to that effect. Which I think can be interpreted as waiting as late in the signal chain as possible to pad down the signal.

Well he really is advocating for distortion of the mic preamp transformer. Pads are designed to stop distortion from happening.

Saturation = Distortion.

I have some pads can do that:

Radio Design Labs STP1 Attenuator, can s'posedly attenuate 85 dB. I have 'em in the patch bay and and put 'em after the pre and compressor (if used) going into the DAW, or mebbe between the pre and a compressor, etc. I don't hear a great deal of difference and so haven't used 'em inna while...

[Nick Sevilla]

I have some pads can do that:

Radio Design Labs STP1 Attenuator, can s'posedly attenuate 85 dB. I have 'em in the patch bay and and put 'em after the pre and compressor (if used) going into the DAW, or mebbe between the pre and a compressor, etc. I don't hear a great deal of difference and so haven't used 'em inna while...

85 dB? LOL might as well just plug the microphone straight to the converter, nothing in between.

[floid]

As counterpoint, Scodiddly's simplified JFP has Scott Hampton's article fresh in my mind. In it he advocates for placing the pad after the preamp input transformer, "b/c transformer saturation can be cool and most mics are unlikely to cause huge amounts of saturation," or words to that effect. Which I think can be interpreted as waiting as late in the signal chain as possible to pad down the signal.

Well he really is advocating for distortion of the mic preamp transformer. Pads are designed to stop distortion from happening.

Saturation = Distortion.

Indeed.

[Scodiddly]

People like distortion.

[emrr]

Pad between input transformer and active circuit is dependent on transformer headroom, very few will distort from a mic source. Some will.

[Scodiddly]

Pad between input transformer and active circuit is dependent on transformer headroom, very few will distort from a mic source. Some will.

There is always some kind of effect from a transformer, though the better ones will not have much effect.

[emrr]

Pad between input transformer and active circuit is dependent on transformer headroom, very few will distort from a mic source. Some will.

There is always some kind of effect from a transformer, though the better ones will not have much effect.

Jensens are “better”, but they will distort on low bass frequencies with a modern high output condenser on something loud. An old UTC A-10 won’t. Gotta dig into the definition of “better”.