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Author Topic: Is levels peaking at 0 to high?  (Read 23799 times)

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Offline firemt66

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Is levels peaking at 0 to high?
« on: June 17, 2023, 11:02:51 AM »
Hello,
            Recently I recorded a few shows on my Samsung phone using the internal Mic, they sound pretty good.the levels peak at 0, At least in audacity that player only goes to 0 so i cant see if it goes higher, I hear no distortion when I listen back to them. When I use my M10 usually it peaks around negative 5 or 4. Maybe sometimes even lower just so I don't have to keep checking the levels. Is there a player that goes above 0 so I Could See if the levels are actually Higher? I bought one of those usb cables that connects to my phone so i can use my CA 14 card mics and it worked fine, again i heard no distortion with playback. Thanks for any input...Scott

Offline firemt66

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Re: Is levels peaking at 0 to high?
« Reply #1 on: June 17, 2023, 11:55:33 AM »
I've just discovered an app for androids ASR Voice Recorder and it has  gain control. I lowered it to -3 recorded something at home here and the levels peaked at -3 in wav 1411 kbps 48mhz 16bit.there is no option for 24bit.The app has an option for 32 bit wav. Should I go with that or just the regular wav option?
« Last Edit: June 17, 2023, 12:07:16 PM by firemt66 »

Offline goodcooker

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Re: Is levels peaking at 0 to high?
« Reply #2 on: June 17, 2023, 12:36:08 PM »

If it sounds fine it is fine. For a recording made with the internal mic of a phone I wouldn't sweat it too much if the peaks that hit zero didn't cause distortion.

For phone recordings with CA mics and no preamp I'd just go with 16bit/48kHz. I don't think there's any real gains to be had with that setup recording live events at higher resolution.
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Offline adrianf74

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Re: Is levels peaking at 0 to high?
« Reply #3 on: June 17, 2023, 01:33:06 PM »

If it sounds fine it is fine. For a recording made with the internal mic of a phone I wouldn't sweat it too much if the peaks that hit zero didn't cause distortion.

For phone recordings with CA mics and no preamp I'd just go with 16bit/48kHz. I don't think there's any real gains to be had with that setup recording live events at higher resolution.

Pretty much it -- if it's not sounding clipped, it likely isn't (terribly) affected.  You could always run the file through de-clip in iZotope RX Audio Editor to see if there's any real issue.  Other than that, try and set levels a little lower if you can to avoid this in the future.
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Offline firemt66

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Re: Is levels peaking at 0 to high?
« Reply #4 on: June 17, 2023, 01:58:36 PM »

If it sounds fine it is fine. For a recording made with the internal mic of a phone I wouldn't sweat it too much if the peaks that hit zero didn't cause distortion.

For phone recordings with CA mics and no preamp I'd just go with 16bit/48kHz. I don't think there's any real gains to be had with that setup recording live events at higher resolution.

Pretty much it -- if it's not sounding clipped, it likely isn't (terribly) affected.  You could always run the file through de-clip in iZotope RX Audio Editor to see if there's any real issue.  Other than that, try and set levels a little lower if you can to avoid this in the future.


Unfortunately I don't have izope to try that and phone apps that i have has no recording level control other than not higher than 0 apparently. However I do have auducity. this new app i d/l this morning does have gain control for which i lowered to -6. Guess I'll find out this thursday when I go to my next show to see actually where the recording level peaks at...
« Last Edit: June 17, 2023, 02:24:12 PM by firemt66 »

Offline kuba e

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Re: Is levels peaking at 0 to high?
« Reply #5 on: June 18, 2023, 04:23:28 AM »
This is a logarithmic scale. The highest signal is 0 db, the lowest signal is -96 db (for 16 bit, -144 db for 24 bit). In Audacity, you can also switch to a linear scale (1 - 0 - -1).

When you record too much amplified audio signal, the signal will be clipped. The signal does not fit in the given range. What exceeds 0 db will be cut. If only a small part of the signal is cut off, it is possible to tolerate it. But when the larger peaks of the signal are cut off, it sounds very disturbing . And it can no longer be corrected afterwards. When you turn down the volume in Audacity, the clipping stays there, it just lowers the overall volume. There is a special iZotope De clip tool mentioned by Adrianf74. It uses an algorithm that artificially restores cut peaks. But that's just a rescue, it's the best to record without clipping.

When recording, you need to amplify the signal so that it does not exceed 0 db. Try to find an app that allows gain control. There is also a lower limit. The signal should not be too low, because then the noise increases (noise/signal ratio). What level to set is a question that has been discussed a lot here. I usually set the level to -9 db. It gives me some headroom for loud sounds and the noise/signal ratio is good.

The app has an option for 32 bit wav. Should I go with that or just the regular wav option?

Go with 16 bit. Self phones don't have 32 bit A/D converter.
« Last Edit: June 18, 2023, 05:27:26 PM by kuba e »

Offline jielkade

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Re: Is levels peaking at 0 to high?
« Reply #6 on: June 18, 2023, 12:26:49 PM »
Try the german app "field recorder".

Offline bonghitwillie

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Re: Is levels peaking at 0 to high?
« Reply #7 on: June 18, 2023, 03:08:00 PM »
i always try and keep it well below 0 bc you cant fix if over recorded.

Offline morst

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Re: Is levels peaking at 0 to high?
« Reply #8 on: June 18, 2023, 04:52:21 PM »
Digital recording only goes up to -0dB as "full scale" for samples.
The interpolated waveform can peak over -0 dB, but samples in the PCM world can't be higher than that, mathematically. Different software and hardware handle this in various ways, so some might be able to meter above full-scale, but I can't think of an example. Some peak meters or limiters only light up when there is more than one sample in a row at full-scale.

For practical purposes, if only the very peaks of the waveform hit full-scale for one sample at a time, you should be in great shape.
Peaking on the snare drum or other short time duration sound will probably not be audible the same way that peaking on a continuous tone would be, such as a loud sustained note on a bass guitar...

I hope this helps.
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Offline DSatz

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Re: Is levels peaking at 0 to high?
« Reply #9 on: August 22, 2023, 03:42:46 PM »
It's easy to assume that all metering nowadays works the way we want it to, because there's really no good excuse for it not to. However, there could be exceptions including well-intended ones (e.g. if the designer thinks, "no one can possibly hear a single-sample overload"). So it's worth loading the recorded waveforms into an editing program on a desktop computer and looking at the peaks in some detail. See whether they appear to run into some kind of limiting or not, or whether they seem unconstrained.

In live recording it is quite rare for signal peaks to remain uniform for any substantial length of time; when they do, it usually indicates some kind of electronic processing (limiting) along the way that is forcing them to fit a common peak amplitude. Whether that is occurring in your equipment or in some preceding equipment in the venue, you'll need to determine case by case. Some recorders and ADCs do, indeed, smash samples that come close to 0 dBFS--and sometimes you want that, at least for safety. But in live recording generally it's better to record first and process later, rather than to "bake" a certain kind and amount of processing into the only recording that you have.

With 16-bit recording, it's very rare that a recording venue is so quiet that you have to run very close to the limit. Typical real-world occurrences make that a dangerous practice; even if you get a run-through of a piece, the performance may easily be 2 - 3 dB louder than the rehearsal at some point or other. After years of analog live recording on open-reel tape, where the dynamic range was distinctly less than 16-bit digital and I got to be a bit of a hotshot at setting my levels so that they just went into the red briefly on peaks and came right back out again, the idea of crowding up against the absolute limit of a digital recording in a live situation makes no sense. If your peaks are anywhere in the top 6 dB without going over, count that as a complete success.

Again, I mean that advice for live recording. In dubbing or processing situations, with the live recording safely "in the can", then it does make sense to approach 0 dB closely IF you're sure of your metering. But that's a real IF. The PCM-F1, for example, had digital meters that were driven from a rectified, analog signal at the input, and they could under-read by as much as 4 - 5 dB in live recording situations; only the "PEAK" indicators were digitally driven, and even those didn't come on unless there were three or more consecutive overloaded samples. It was, after all, a consumer device even though pitched to advanced consumers. Many DAT recorders had similar metering.

--best regards
« Last Edit: August 30, 2023, 11:53:06 AM by DSatz »
music > microphones > a recorder of some sort

Offline morst

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Re: Is levels peaking at 0 to high?
« Reply #10 on: August 23, 2023, 04:31:41 AM »
Hey DSatz - if you publish a book, I'd like to buy it, or if you are considering it but need an editor, I'd be up to help proofread/edit.


I always appreciate your insight.
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Offline rocksuitcase

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Re: Is levels peaking at 0 to high?
« Reply #11 on: August 23, 2023, 11:14:20 AM »
Hey DSatz - if you publish a book, I'd like to buy it, or if you are considering it but need an editor, I'd be up to help proofread/edit.


I always appreciate your insight.
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seconded. I knew Ron Streicher. I presented at AES in 1986/1987. Dsatz, YOU have a great method for explaining this type of knowledge. It is one thing to know acoustics or microphonics, another to explain it in terms most can understand.
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Offline fireonshakedwnstreet

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Re: Is levels peaking at 0 to high?
« Reply #12 on: August 23, 2023, 02:38:51 PM »
I want to have at least 10db of digital headroom no matter what happens. You can compress/limit/normalize in post and make it as loud as you want.
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Offline DSatz

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Re: Is levels peaking at 0 to high?
« Reply #13 on: August 26, 2023, 08:06:49 PM »
fireonshakedwnstreet, just for me, could you please tell me whether you mean:

(a) you want to set your levels so that 10 dB goes entirely unused permanently at the top (i.e. for you, a recording with its highest peak at -10.1 dB is a more successful recording than one with its highest peak at, say, -4 dB),

or do you mean:

(b) you set your levels ~10 dB lower than what you think is probably necessary, to allow for unexpected occurrences--and then the more of that 10 dB that actually gets used, the more that proves the value of your strategy.

Is it your actual goal to obtain a live recording with 10 dB of unused dynamic range at the top, in other words?
Or is your approach a means to a different end, i.e. being very, very sure not to over-record?

I'm asking because I think that different people think of "headroom" in these two rather different ways. Or maybe you mean something else by it that I don't know about. (Hint: In professional audio the meaning of "headroom" is definitely (b), while anything like (a) is generally avoided except as a last resort, e.g. to work around the limitations of some interface or piece of equipment that has an overload problem.)

--best regards

p.s. Many thanks for the kind words in the messages above.
« Last Edit: August 27, 2023, 12:59:52 PM by DSatz »
music > microphones > a recorder of some sort

Offline SMsound

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Re: Is levels peaking at 0 to high?
« Reply #14 on: August 26, 2023, 08:14:21 PM »
If you use a recorder with limiters, then the limiters will kick in somewhere in the region of -7dB. Even with good analog limiters like the ones in my MixPre, I can hear the difference between limiters and no limiters (even after loudness matching). It's a subtle difference, but I definitely prefer the no-limiter sound.

These days, with low-noise preamps available in prosumer grade recorders, why would you come close to -0... I record classical and opera in quiet environs and *really* care about minimizing noise, but I shoot for peaks at -18dB... the ambient noise in an empty concert hall is still higher than MixPre's native noise at -18dB, so there is zero value in pushing it higher and taking risks*

*technically, maybe there's value from a signal-to-noise maximizing perspective? I don't know. Still see no point to doing this in practice.
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