Topic: 32Bit Float recording - The Technical view

[morst]

Darn! I go away for a few hours and miss a bunch of great discussion! I always appreciate gutbucket’s well worded explanations of the technical aspects of our craft/hobby. Thank you. Indeed, I never actually normalize right up to 0dbFS because of the mentioned inter-sample clipping possibility. I have the normalize function in my Wavelab setup dialed to -0.2dbFS. I should have made that note in my post.
Dithering of 32-bit float to 24-bit fixed is an interesting subject to me. I have chosen not to dither in this situation because the audio content inside the 32-bit float container is already very close to 24-bit in depth. Going to 16-bit will truncate a significant portion of the low level content so dithering is appropriate here. I’d be interested to hear other opinions about this (admittedly obscure) subject.

To my understanding, it's exactly 24 bits of data precision.
https://www.sounddevices.com/32-bit-float-files-explained/

https://en.wikipedia.org/wiki/Single-precision_floating-point_format#IEEE_754_standard:_binary32

1 sign bit
8 exponent bits
23 data bits; as the wiki says: 23 bits are stored explicitly, but in effect, there are 24 bits of data.

[Ozpeter]

The Zoom H1 XLR manual is now online and that confirms that it can create either 16 bit or 24 bit files from the 32 bit float originals, while normalising at the same time.  Or it can normalise while retaining 32 bit float.  The original files are retained of course.

[Dan33185]

48.  There's no chance your mics are more resolving than that.  If you eventually want to do something like recording bats, and slowing them down to listen to, and you get ahold of some appropriate mics, 96 will help.

Ha, can't imagine I'll ever have a need to do that, 48 will work just fine. Tried it out last night, and am confused on something. It created two files for each recording, one titled "TrLR", and another titled "TrMic". I did a little searching, and from what I could understand, the backup was created at a lower recording level to avoid clipping. I thought clipping with 32-Bit Float was considered impossible to begin with? Is having a backup file like that necessary?

[grawk]

Lr is the xlr inputs and mics are the built in mics

[Dan33185]

Hmm...weird, I wasn't able to use the XLR's last night, only the internal mics, but somehow there is audio on both files.

[Dan33185]

Second time using the Zoom H4 tonight, using XLR connected to a soundboard...I'm pretty disappointed. There is a lot of clipping, the big selling point was "The H4essential captures every nuance of your sound ensuring high-quality, clip-free audio in every take." I'm guessing user error, but I'm not sure what, I thought it was just set it and forget it.

[grawk]

It’s always possible to overload inputs.  For consumer gear you regularly need attenuators for a board patch.

[Ozpeter]

Max input level is  LINE: +24 dBu, but that requires the trs input, according to the marking on the front.  So if you had it connected to the line output of the board into the mic (XLR) input of the recorder, it would seriously overload well before the 32 bit float converters.  They don't help with analog distortion before them in the signal chain.  Indeed they will make a very good recording of it...

[Dan33185]

It’s always possible to overload inputs.  For consumer gear you regularly need attenuators for a board patch.

Odd, I've used my Tascam DR-60 and 70 without issue when recording from a SBD, which is why I didn't think anything of it. Starting to wonder if I might be better off just sending it back and going with something like the Zoom H4N if I have to monitor levels anyway, at half the price. I like the equipment I have, I am just trying to downsize as much as I can.

Max input level is  LINE: +24 dBu, but that requires the trs input, according to the marking on the front.  So if you had it connected to the line output of the board into the mic (XLR) input of the recorder, it would seriously overload well before the 32 bit float converters.  They don't help with analog distortion before them in the signal chain.  Indeed they will make a very good recording of it...

I believe that it was a line output, it was a 1/4" plug. The recording is salvageable, just caught me off guard that it clipped.

[Gutbucket]

If line-input via TRS is capable of handling an input level of up to +24dBu, it should handle a patch from the soundboard just fine.  I Just checked the on-line manual and found the note below-

"NOTE
To make handling the levels of input signals easy, the H4essential sets input levels according to the types of plugs connected to the input jacks.
• When connecting mic-level devices, use XLR plugs.
• When connecting line-level devices, use TRS plugs."

[Gutbucket]

Double check all the relevant menu settings.  Phantom power off? (may not matter if not available on the TRS inputs, but best to turn it off anyway).  Recorder set to record in 32-bit-floating point  mode? Etc, etc?

Also it is entirely possible the signal was distorted prior to reaching the recorder.   Any confirmation that it was clean? Maybe by checking with headphones prior to or during recording?

[Dan33185]

Double check all the relevant menu settings.  Phantom power off? (may not matter if not available on the TRS inputs, but best to turn it off anyway).  Recorder set to record in 32-bit-floating point  mode? Etc, etc?

Also it is entirely possible the signal was distorted prior to reaching the recorder.   Any confirmation that it was clean? Maybe by checking with headphones prior to or during recording?

Phantom power was off. I don't even see an option to change the bitrate, I think that's just the default and it can't be changed. I did not get a chance to listen to it during the recording, I was lucky to get the patch at all, you could tell this was not something they do all the time and they were just hoping it was the right output. Maybe with a more experienced person running sound I might get better results. I have a show today I am able to patch to the SBD as well, I'll give it another try. I'll leave samples of the recording, maybe someone can give more insight than I can gain from it.

RAW File:  https://drive.google.com/file/d/10YB3syMj4nx8GCK8Q2ejivtQSh6-sRrG/view?usp=sharing

Normalized:  https://drive.google.com/file/d/1rTZQZmA2F8WPvEk3NG-cDTeT6jqx7Omi/view?usp=sharing

Waveform:

[Ozpeter]

I'd lay money that it's clipped at the source.  Singer's mic so high level compared to the band?  One 'problem' with today's recorders is that they make excellent recordings of the warts and all...

[morst]

If line-input via TRS is capable of handling an input level of up to +24dBu, it should handle a patch from the soundboard just fine.  I Just checked the on-line manual and found the note below-

"NOTE
To make handling the levels of input signals easy, the H4essential sets input levels according to the types of plugs connected to the input jacks.
• When connecting mic-level devices, use XLR plugs.
• When connecting line-level devices, use TRS plugs."

"THE" soundboard? What console? They have different max output levels...
If the speaker system is small and/or underpowered, the operator might be running the board up near clipping in order to achieve their desired output levels.

[Dan33185]

If line-input via TRS is capable of handling an input level of up to +24dBu, it should handle a patch from the soundboard just fine.  I Just checked the on-line manual and found the note below-

"NOTE
To make handling the levels of input signals easy, the H4essential sets input levels according to the types of plugs connected to the input jacks.
• When connecting mic-level devices, use XLR plugs.
• When connecting line-level devices, use TRS plugs."

Ok, just to make sure I am understanding it...when I am using my mics or connecting to a soundboard/mixer that has an XLR output, use the XLR inputs on the Zoom. If I am connecting to soundboard/mixer with a 1/4" connection, I should be using the "Line In" input? So using a 3.5 MM input with a dual splitter and 1/4" adapters to the soundboard should work? No attenuator needed because it's 32 bit float?