Topic: Do I need to use my mic's pads to protect my 32-bit float recorder?

[taperdave1998]

Alright, here comes my (likely dumb) question and slight story:

I'm going to be taping a show in eight days. Formerly used an H4n Pro, but we're in the era of 32-bit float! May as well embrace it. I bought a Zoom F3 last week that arrived faulty. It wouldn't spit out my micro SD card. Sent it back, received a new unit. Same exact thing, even worse actually... and this is a SanDisk card, not some crappy Onn./dollar store card.

So...

I ordered an H1 XLR! I've been stealthing with the H1essential all throughout 2024 and never had any weird issues with spitting out the exact aforementioned memory card.

My mics are sE8s with cardioid caps.

The sE8s have a sensitivity of 25 mV / Pa (-32 dBV). The H1 XLR has a max input of +4 dBu (which is the same spec as the F3, interestingly enough).

Do I need to use my pads to tape this show? Or rather, should I? I have no way of knowing how loud this concert is gonna be, as it's for a band I've never seen in a theatre I've never been to. Will be taping from behind the board at 7-10' in the air, likely DIN.

In essence, just because my mics can handle 139/149/159 dB, I want to make sure I'm clipping the actual recorder. Thank you very, very much.

[daspyknows]

I will let the people who might know that gear answer the question but would recommend you doing a practice show at a bar or something just to see if it works.  If it doesn't you get a second shot.

[aaronji]

At 25 mV/Pa, those mics will output 4 dBu at about 127 dBSPL. That's really loud, like "worrying about my hearing, even with decent protection" loud...

[Gutbucket]

25 mV/Pa is pretty sensitive and will produce a relatively hot output, but as Aaron mentions 127dB is very, very loud.  I'd not expect you to have a problem unless recording on stage close the the drumkit where transient peaks can be extreme. 



^ Ignore the blue highlighted row/column which is just an example for 20mV/Pa. 
That table sourced from here: https://sengpielaudio.com/calculator-transferfactor.htm

[grawk]

That’s a fantastic chart.

[Thelonious]

This thread, and the chart, have been very helpful to me so thank you for the original post and responses so far!

Given that I’m recording, most often, in 32 bit with a Mixpre 6 ii or Zoom F3, my only concern when setting  up my mics (from a level perspective), is ensuring I don’t overload the analog stage.

Based on the above I am understanding that with the mic sensitivity, the chart, and a very approximate level of the show volume I can establish the output level of the mics.

Is there an easy way to establish the input level at which a recorder will overload for these devices (e.g., is this a published spec) or is there an easy general level that is considered safe across all devices?

Thanks in advance, this thread cemented an important concept for me and will allow me to record loud sources stress free going forward. 

[taperdave1998]

This thread, and the chart, have been very helpful to me so thank you for the original post and responses so far!

Given that I’m recording, most often, in 32 bit with a Mixpre 6 ii or Zoom F3, my only concern when setting  up my mics (from a level perspective), is ensuring I don’t overload the analog stage.

Based on the above I am understanding that with the mic sensitivity, the chart, and a very approximate level of the show volume I can establish the output level of the mics.

Is there an easy way to establish the input level at which a recorder will overload for these devices (e.g., is this a published spec) or is there an easy general level that is considered safe across all devices?

Thanks in advance, this thread cemented an important concept for me and will allow me to record loud sources stress free going forward. 

I guess don't really understand what you're saying. The MixPre-6 II has a listed spec of "Mic XLR: +14 dBu." This is significantly higher than the F3, H1 XLR, FR-AV2, etc. which all share the +4 dBu max in from mic XLRs. I'm under the impression your MixPre can handle virtually anything you'd throw at it and that it would be difficult to clip the analog in.

[Thelonious]

^ I think you just answered my question. The max level at the input of the F3 is +4 dBu and the Mixpre 6ii is +14dBu and that’s the max input level at the XLR in to avoid analog clipping. Is that correct? If so, is that at the line in or mic in mode?

Apologies if I’m missing something obvious here.

[taperdave1998]

^ I think you just answered my question. The max level at the input of the F3 is +4 dBu and the Mixpre 6ii is +14dBu and that’s the max input level at the XLR in to avoid analog clipping. Is that correct? If so, is that at the line in or mic in mode?

Apologies if I’m missing something obvious here.

The MP6-II specs are:

Mic XLR: +14 dBu (limiters on or off)
Line XLR: +28 dBu (limiters on or off)

You're all good. I myself have very little technical knowledge on the matter myself, but this makes the most sense to me. What mics you running?

[Thelonious]

^ I think you just answered my question. The max level at the input of the F3 is +4 dBu and the Mixpre 6ii is +14dBu and that’s the max input level at the XLR in to avoid analog clipping. Is that correct? If so, is that at the line in or mic in mode?

Apologies if I’m missing something obvious here.

The MP6-II specs are:

Mic XLR: +14 dBu (limiters on or off)
Line XLR: +28 dBu (limiters on or off)

You're all good. I myself have very little technical knowledge on the matter myself, but this makes the most sense to me. What mics you running?

Thanks this is helpful. I don’t run limiters and I think they only matter for digital levels (not an issue with 32 bit). I didn’t realize the specs you noted were max level at the xlr before analog clipping. That’s what I needed to know so thanks again!

I have a few sets of mics with different sensitivities which is why I asked. If I’m going to record a really loud band and think I could be close to a stack, or on stage near drums, mic selection is one thing (along with a pad or an attenuator) that could help.

Line audio cm4s/om1s
Km 184s
Akg ck61-3
Scheops mk22

I also run CS HEBs sometimes but that is 24 bit through an edirol r07 so levels matter at both the analog and digital stages in that scenario and the noise floor is also more of an issue which is why using an F3 where you meant to almost “not worry about levels” is such a mental adjustment for me.

[aaronji]

^ Generally speaking, unless you have both very sensitive mics and a very loud source, you will be OK with most current recorders. The exceptions would be if you are quite close to a high SPL instrument (snare or bass drum, horns, guitar cabinets turned up high, etc.) or have too much analog gain dialed in (which isn't an issue in a well-designed 32-bit floating point device).

Also, the better limiters have an analog stage. With my first generation MixPre-6, I always set levels a bit on the conservative side, but engage the analog limiter just in case I misjudged something. I think it has only kicked in once or twice. Better safe than sorry, though.

[Thelonious]

Thanks Aaron,

I didn’t realize that the limiter was at the analog stage. It sounds like there is an opportunity to figure out how to set it, at a level that should never kick in, but below the max input level of the the analog in, and this would eliminate the possibility altogether.

Thank you for helpful tip!

[aaronji]

^ There are several flavors of limiter: analog, digital, and hybrid. If you are recording in 24-bit, with analog limiters, it can work well. I am unsure to what extent digital or hybrid limiters are beneficial. The market-speak can be hard to interpret...

[Thelonious]

^ Thank you, I will investigate further.

So it sounds like the answer to the OP’s post is.

1) they probably don’t need a pad in all but very extreme cases (e.g., on quite stage close to drums, right next to stack at very loud show)
2) using line in in these situations the mic pad could be used (or switching to line in)
3) there MAY be an opportunity to use an analog limiter but this requires further investigation as some of them are digital (which wouldn’t help) and the way they are described can be misleading in some cases

Thank you again to the OP for asking this question. Very helpful info here.

[Ronmac]

Thanks Aaron,

I didn’t realize that the limiter was at the analog stage. It sounds like there is an opportunity to figure out how to set it, at a level that should never kick in, but below the max input level of the the analog in, and this would eliminate the possibility altogether.

Thank you for helpful tip!

The limiters are disabled in 32bit float mode, for obvious reasons.