Definition of Crunch

[normus]

Hello everyone. This is my first post on this site. I'm glad to have this place to ask questions.

Here's #1. How would you define crunch. Everything I read just seems to assume that everyone knows what 'crunch' is. Can it be explained with a clipping of a sine wave? What is the actual effect and how does it sound. Clipping of top frequencies? Distortion in the bottom frequencies? PLease help. Please try and explain it without another term such as fat as that will do me little good. DO you know of a site with a full glossary of these types of terms? A comparison of Clean, Crunch and distortion would be much appreciated.

Thanks.

[JohnH]

Hi normus, and welcome to GN2. Im no expert in the definitions of sounds, but that has never stopped me from pretending, so heres my potted version:

Lets start with the natural guitar sound. It comprises a fundamental note (which is what it is tuned to), and harmonics at 2x, 3x, 4x etc times the fundamental. Depending on the pickup and technique the higher harmonics get less and less.

Feed that into an amp with minimal distortion, and that is 'clean'

As a guitar amp starts to get turned up louder, or fed with a higher signal volume, it starts to add distortion because it cannot maintain a larger signal output, and so it clips the top of the signal . If it is a good guitar amp, it does this smoothly, so a pure sine wave signal gets squashed rounded tops that become steadily more compressed as input is increased. A bad amp, or normal hifi amp stays clean until it slams into a hard barrier due to the power supply voltage, and suddenly clips hard with a flat top. All distortion adds to the higher harmonics, giving more edge and bite, but a bad amp sounds harsh and buzzy, but a good amp sounds rich and smooth. Traditionally the good amps are driven by tubes, which by their nature, do a smooth rounded clipping instead of the hard type, which normal solid state-amps do. These days there are hybrids and digital emulations which also aim to achieve this character

The first stage where a good amp is just begining to be pushed beyond clean is called 'crunch'. the sound has some higher harmonics, just 'breaking up', but not a huge amount of very high harmonics, since the wave form is still rounded and not flattened. the original character of the sound comes through - great for blues and some classic rock

Add more gain to the signal, and the effect increases with more higher harmonics - the signal gets more flattened - the amp is being 'overdriven'

All of these tendencies increase as the amp is pushed harder, and the extra high harmonics due to distortion increase.

Good luck exploring these sounds

John

[RandomHero]

Wow.

And here I thought "crunch" was the sound a guitar made when you whaled on a groupie's skull with it.

I mean, think about it.

"That 17 lb. Les Paul has great CRUNCH!"

"Are you kidding? That plywood Squier is about as crunchy as yogurt."

...it made sense to me anyway. XD

[wolf]

Yeah I'd agree with RandomHero.
I always thought crunch was a huge amount of distortion, with the second harmonics being emphasized and lacking the high harmonics.
To me the archetypal "crunch" sound is the rhythm guitar part in Led Zeppelin's "Whole Lotta Love". Does everyone agree with this for an example of crunch?

[UnklMickey]

Wolf,

when i first heard the term, i thought as you did.

certainly in a more onomatopoeic sense, your description would seem more accurate.


but as it turns out, when most guitarists i've talked to, say crunch, they mean a mild to moderate distortion. and preferably favoring even harmonics.



i'm sure the term has different meanings according to locale.


oh, and also it's a term for a bad quality in a tuber. lol



unk

[JohnH]

OK - I would admit to probably understating the level of dirt inherent in the word 'crunch' - and it does seem to have a broad meaning which varies depending on context. Also, maybe it is a word like 'speed' or 'quality' for which you can have low or high values?

Anyway, heres where I'm coming from, quoting from my favorite amp maker:

Marshall describes how the clean channel, with higher gain settings tends towards a 'bluesy crunch' - the following is from the DSL401 handbook, refering to the clean gain control:

"This controls the preamp level of the clean
channel, at lower settings the sound will be very
clean and at higher settings the sound will start
to ‘Crunch’ up in a traditional blues sort of way."

The word 'crunch' is also used in describing the overdrive channels - here, refering to the overdrive gain:

"This controls the amount of gain drive available
for the overdrive channel, from mildly almost
clean crunch to super-saturated overdrive,
depending where this control is set, i.e. lower is
less and higher is more."

Peavy , on their JSX head, name their channels 'Clean', 'Crunch' and 'Ultra'. Theres plenty of gain available within 'Crunch', but less than on 'Ultra'.

So out of that, it would seem that 'Crunch' involves a significant level of distortion, but less than maximum.

Finally, the 'word of the week' prize goes to Unklmickey for 'onomatopoeic', which seems to mean words that sound like what they mean - such as 'woof' or 'quack' (oops - bad example, smitations to anyone who mentions Sultans of Swing!)

cheers

John

[Happyguy]

Ive always thought that it was on the vintage side of distortion... agree with wolf on the whole lotta love. When you can actually hear the differences in strength the dude is wacking the guitar. Distortion but not realy sustaining that long. Thats my thoughts.

[UnklMickey]

johnh said:

...Finally, the 'word of the week' prize goes to Unklmickey for 'onomatopoeic'....

first, i'd like to thank the Academy......

johnh said:

...such as 'woof' or 'quack' (oops - bad example, smitations to anyone who mentions Sultans of Swing!)...

yeah, let's not go down that path again.

[normus]

Okay. So it wasnt' as dumb a question as I'd thought. Thanks all.

[Ripper]

To me...

Helter Skelter = Crunch

Revolution = Fuzz

Latina ladies = Too much fuzz! ....ummm but I like it!

[UnklMickey]

i've heard Helter Skelter.

and i've heard Revolution.

but i've never heard Latina Ladies..........

......what album is that on?

[ChrisK]

As a guitar amp starts to get turned up louder, or fed with a higher signal volume, it starts to add distortion because it cannot maintain a larger signal output, and so it clips the top of the signal.

An amp begins to distort the signal. A solid state preamp tends to clip the waveform peaks (although most SS pre-amps try to have a soft(er) clip). A SS power amp at some point just clips. SS devices, being electronic devices have hard(er) clipping thresholds.

A tube preamp, being single-ended, tends to round the top (+) part of the waveform (saturation/gain limitation) and clip the bottom (-) part of the waveform (insufficient gain/cutoff). This type of clipping will add second order harmonics (this is """good""" stuff). A single-ended tube power output stage will just add more of the preamp type of distortion. This may be crunch to Fender enthusiasts.

A push-pull tube power amp will tend to round both of the waveform peaks, giving a fuller, warmer, compressed sound ('specially with a tube rectifier), and eliminating any internally generated (within the power output stage) second order harmonics. Of course (methinks anyway), any preamp generated harmonics "should" be relatively faithfully (remember, this is a tube amp) reproduced by the power stage. This may be warmth and roundness to Fender enthusiasts.

Tubes, being electro(nic)/mechanical devices tend to have softer clipping thresholds.


Of course, a set of EL34's ( a la' Marshall) may be called crunch as well.


Regarding "good" and "bad" amp types

You say to-may-to, I say to-mah-to,
You say po-tay-to, I say po-tah-to,
You say 'erbs, I say herbs ('cuz there's a blinkin' "h" in it).


Tube amps are inconsistent, lousy, crappy, ugly, inaccurate distorting pieces of early engineering efforts that have universally failed to accurately reproduce the input waveform. (Well, there's them "glass audio" folks too.)

Yet, fer some reason, folks still like 'em (they do remind me of the legend in my own mind....).