Here’s another take on this. Let’s consider microphone specifications, preamp
noise, and bit depth.
The problem with microphone specifications is people not understanding them. We
too often look at one spec, the noise floor. I have microphones with
considerably higher noise floors than others and yet the noise is no higher.
This is because the impedance is lower, therefore the mic records at the same
level with 10 dB less gain on the pre. The gain noise on a good pre will remain
the same throughout the gain range. Conversely, some inexpensive pre’s will add
noise as you turn them up. Building a pre with one optimal gain will make it
very quiet.
Next up is the signal to noise ratio. If a mic has an 80 dB ratio it will be
the same regardless of the recording level in 32 bit float, and pretty much in
24 bit too, provided you record at a reasonable level. The problem is in
perception. When people record at a low level and turn it up in post they’re
focusing on the noise floor and think it’s louder. It’s not unless you’re
recording in 16 bit. Then you might hit the noise floor of a 16 bit recording,
which is -96 dB. The noise floor of 24 bit is -144 dB. And the noise floor of
32 bit float is -758 dB. So with 32 bit float you’re absolutely going to have
that 80 dB signal to noise ratio regardless of the level you recorded at.
Therefore, the signal to noise ratio of a file peaking at -60 dB is going to be
exactly the same as a file recorded peaking at -6 dB. Turning up the low level
recording is not going to change the ratio on a 32 bit float recording because
there is no noise floor on the recorder.
The only thing that can add noise is the pre. And this is essentially
eliminated when building a pre for a 32 bit float system. As I said, building a
pre with only one gain setting makes it quieter. This is why high-end pre’s
often have stepped controls rather than floating controls. Dialing in steps is
more efficient than a floating control. And building a pre with only one gain
level eliminates the entire variable gain structure of that pre. This is why
they can build quiet pre’s even for an inexpensive recorder. Although, as we’ve
seen in the past these pre’s have improved enormously over the years anyway.
Hth,
Tom
From: midimag-bounce@xxxxxxxxxxxxx <midimag-bounce@xxxxxxxxxxxxx> On Behalf Of
Ross McGregor
Sent: Wednesday, March 13, 2024 3:49 AM
To: midimag@xxxxxxxxxxxxx
Cc: Rossmcg49@xxxxxxxxx
Subject: [freelists-midimag] Re: 32 bit float and zoom
HI Tom,
I can’t see the point of putting the fader prior to the disk.
At that point all the noise has been added and damage has been done, so to
speak. So it’s a bit late there.
Obviously better to place it at the front of the pre, to maximize noise, and
give the a d c, a comfortable level to work with.
Ross.
From: midimag-bounce@xxxxxxxxxxxxx <mailto:midimag-bounce@xxxxxxxxxxxxx>
<midimag-bounce@xxxxxxxxxxxxx <mailto:midimag-bounce@xxxxxxxxxxxxx> > On Behalf
Of tom.kingston247@xxxxxxxxx <mailto:tom.kingston247@xxxxxxxxx>
Sent: Wednesday, March 13, 2024 5:16 PM
To: midimag@xxxxxxxxxxxxx <mailto:midimag@xxxxxxxxxxxxx>
Subject: [freelists-midimag] Re: 32 bit float and zoom
Thanks Noah.
The Zoom rep corrected a mistake I mentioned made by the review I listened to.
This is the problem with everyone wanting to be the first. They review things
before they know what they’re talking about. The correction is that as I said,
you cannot adjust the recording level, however, you can adjust the level prior
to it being written to the SD card. I said the faders in the mixer are just for
playback levels. And that is their default function. But you can go into the
menus and set the recording to post mixer. Now the raw recording will still be
at the same level, however, adjusting the fader will adjust the level written
to the file. So it’s still not a pre-amp level control. It’s just doing the
same thing you would do in post, be it on the recorder or in your DAW. So I’m
not sure what the point of it is. I just wanted to clarify this.
Regards,
Tom
From: midimag-bounce@xxxxxxxxxxxxx <mailto:midimag-bounce@xxxxxxxxxxxxx>
<midimag-bounce@xxxxxxxxxxxxx <mailto:midimag-bounce@xxxxxxxxxxxxx> > On Behalf
Of Noah Carver
Sent: Tuesday, March 12, 2024 4:23 PM
To: midimag@xxxxxxxxxxxxx <mailto:midimag@xxxxxxxxxxxxx>
Subject: [freelists-midimag] Re: 32 bit float and zoom
For those looking for that interview, here is a direct link to the episode:
https://www.livingblindfully.com/episode-266an-interview-with-zoom-about-their-new-accessible-essential-recorders-your-best-and-worst-airline-security-experiences-and-sharing-the-transport-duties-when-youre-a-blind-parent/#main
A direct link to the timestamp at which the interview begins can be found on
that page. Also note that podcast reviews of each recorder will be posted to
the Living Blindfully podcast feed shortly.
--
Noah Carver (He/They)
Candidate, B.M. '26 | Applied Music (Performance) -- Voice
Eastman School of Music | University of Rochester
<https://www.freedomscientific.com/Training/Certification>
+1 (207) 557-9143 <tel:+12075579143>
noahcarver494@xxxxxxxxx <mailto:noahcarver494@xxxxxxxxx>
On Tue, Mar 12, 2024 at 11:35 AM <bspro@xxxxxxxxxxx <mailto:bspro@xxxxxxxxxxx>
wrote: