"once clipped, now shy......"

[Bumpy]

I record mainly acoustic guitar and vocals. I most usually cut a rhythm track and then add layers as appropriate. I started off creating my tracks in 24bit, but have since lapsed into using 16bit mode. I am back to creating in 24bit, but my recording levels seem low.

I make gain adj. in my chain, but when I clean and mix, they still seem too low. I can boost at mixdown, but this seems contrary....I intuitively feel like I should "cut levels" at mixdown rather than boost.

I started (24bit) trying to keep my levels between -2dB and 0 but I clipped a good composition and got bummed. Now I am too shy, perhaps.

Whats a good level to shoot for when capturing acoutic instrument tracks?

Also, I hear talk about "more headroom" when recording in 24bit. Please explain.

thanks

 

[regebro]

Headroom is the difference between the lowest level you can record in (which in analog is the noisefloor, and in digital is 1 bit) and the highest level. 24 bits is 8 bits more than 16, and hence you have 8 bits (=48db) more headroom.

A good level is the highest level where you get no clipping. Your recording software and/or hardware SHOULD tell you when you have clipped, in no uncertain terms (a read light is typical to denote max level, which is usually assumed to be clipping).

 

[AlChuck]

I hear talk about "more headroom" when recording in 24bit. Please explain.

The number of bits used to represent each sample in a digital audio data file is directly related to dynamic range, which is the difference between the biggest and smallest amplitude value. The more bits, the finer the resolution of the steps between amplitude from one value to the next that are represented, and the more levels you can represent , therefore the dynamic range is greater. "More headroom" is another way of saying "more dynamic range." 16 bits allows 2-to-the-16th values (65,536), while 24 bits allows 2-to-the-24th values (16,777,216).

Expressed in dB, data at 16-bit resolution has a theoretical dynamic range of 98dB, whereas 24-bit offers a dynamic range of 120 dB.

 

[struberg]

the headroom means the theoretical amount of quantification steps left while recording.

with 16 bit you will have a maximum of 2^16 = 65535 different voltage levels available.
with 24 bit, you theoretically get 2^24 = 16777215 different steps.

Therefore you theoretically don't have to use all the input level your recording equipment can afford (ie record as hot as possible) to gain the same result. And thus, you have more headroom left for peaks.

Unfortunately there is the little word 'theoretically' in all my sentences above
This is, because the quality of the result is also determined by the hiss and thermal noise you'll automatically get.

 

[struberg]

Headroom is the difference between the lowest level you can record in (which in analog is the noisefloor, and in digital is 1 bit) and the highest level.

To be exactly, that is the accuracy or precision of a system. The headroom is an indicator how much is left for eventually incomming peaks without clipping your signal when you record with normal input level.

Take a ruler with 2meters length for example. I am 1.80 meters tall, thus gives a headroom of 20cm for the measurement result. A person who is 2.10 m tall will get the system into clipping

And now think of the same situation while having a 5m long ruler

 

[baekgaard]

16 bit will give you 96 dB of dynamics level (as each bit gives you 6 dB). 24 bit will give you 144 dB.

But in practice, this is limited by the converters you use. Good converters are usually somewhere around 100 dB and up to maybe 120 dB for really good ones.

Anyhow, for answering your question: If you have good converters, you should record 24 bit and keep some headroom so that you don't get clipped. Depending on material, I would personally shoot for recording levels around -6dBFS to -12dBFS with an occasional peak going a bit higher; this will give you some room without sacrificing with too much noise.

If you have lousy converters, you need to get as close to the limit as you dare...

In both cases, and external compressor/limiter may help you avoid digital clipping.


-- Per.