frequency response

[dloweman]

You hear alot about 20hz-20Khz, and I was just wondering where certain instruments fit in to this category. For example what is considered mid-range, vocals? guitar? drums? what has higher frequencies? symbols? etc...any input would be helpful, and i would imagine that i am not the only one that is interested in knowing this. Thanks for any input

 

[MDS]

Different people seem to have slightly different views on what is bass vs mid-bass vs mid-range, etc. Google and you will find...

General rules:
1. Bass: 20Hz - ~400 Hz.
2. Mid Range - ~400Hz - 6 kHz.
3. Treble - ~ 6kHz - 20 kHz.

Each range can be divided into low, middle, and upper and different sources I've read place those ranges differently.

The human voice ranges from 125 Hz to ~3-4 kHz. The fundamental frequency of a typical man's voice is 250 Hz, of a woman 400 Hz. Cymbals definitely fall into the treble to high-treble range.

Most people over age 30 can't hear much beyond 17 kHz. Just for fun, I generated a 5 second sine wave of 17 kHz to see if I could hear it. Only if I make the amplitude 0 dB (as high as possible) AND turn up the volume loud, could I barely hear it. I couldn't discern anything at all above 17 kHz.

 

[TEvo]

Frequencies/Sounds of Music

http://psbspeakers.com/FrequenciesOfMusic.html

 

[rschleicher]

That was a very interesting article. I think most people are surprised to find out how little low bass content there actually is in most music (almost nothing below 40 Hz, except for pipe organ pedal notes, and maybe bass drum and tympani), and how the fundamental tones of even high-pitched instruments are not very high in frequency.

One other comment about guitars - one reason for solid-body electric guitars sounding so different than amplified acoustic guitars (or acoustic guitar played through a microphone) is the lack of high-frequency content in the signal chain for an electric. I'm not sure about the exact frequency response of electric guitar pick-ups, but it is pretty limited. Also, guitar amps usually use 12" woofers as their only speakers. (Sometimes a bit smaller, but the typical arrangement is for 1-4 12" speakers.) So, the high frequency response is limited by the speaker's frequency response, if nothing else.

To capture the higher-frequency transients that make an acoustic guitar sound the way it does (the transients of the initial string impact, for example), you either need to play it through a microphone, or else use special pick-ups that have a wider frequency response. In addition, guitar amps that are specifically designed for acoustic guitars usually have tweeters as well as woofers, to capture the high frequency content better.

BTW - in the telecom world, the basic assumption for the required frequency response needed for adequate voice transmission is 200-3,400 Hz. That's why the sampling rate for digitizing telephone voice circuits was set at 8 KHz (a little more than twice the desired upper frequency limit). Contrast this to 44 KHz for "red book" CDs, to allow frequency response up to 20 kHz..

Most people are familiar with how their own voice sounds a lot different when listening to a recording, compared to how it sounds to yourself. This of course is due to the fact that you are hearing your own voice through not just your ears, but also the sound waves propogating through the bones of your skull, through nasal passages, etc. If your ears are ever plugged up, you hear relatively more through the "low-pass" filter represented by your skull and nasal passages. If any of you have ever had a bad case of tinnitus (ringing in the ears), then you know how it also changes the sound of your own voice. I THINK this is another case of severely rolled-off high-frequency response. I had tinnitus once for several weeks, after going to a Who concert. (Ironic, considering Pete Townsend's hearing problems.) It sounded like my own voice was lisping, but in reality the high-frequency content of my voice was being rolled off. It didn't get any better for 3 or 4 weeks, and then I woke up one morning and the ringing was gone. I've always wondered if my ears actually got better, or if my brain just figured out how to compensate!

 

[MBauer]

Electronics are a big impact

Much of the low bass we hear is generated artificially by electronic means. Mostly for movies attempting to replicate explosions, earth quakes, etc. Many of the these natural sounds generate extremely low frequencies (ELF) and often aren't just moving air, but earth, water, etc. Furniture transducers are often used to replicate these effects. That’s why HT and music systems have such different requirements and it is difficult to have one system perform well with both sets of materials

At one time, a good test was a recording of Tchaikovsky's 1812 Overture, the booming cannons and ringing church bells were a good test. Some performances even used a real cannon(s) to get the effect, as even a bass drum does not have that type of sound pressure.

Accuracy is often a key criterion for a music system as it has to reproduce a known frequency and tone, while an explosion generated for a movie special effect is a bit different, what does a dinosaur walking really sound like?

 

[cbraver]

Good points.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-027

I always recommend these for people who live in apartments where they need to worry about bass disturbing neighbors. A small subwoofer and these is perfect for a little home theater in an apartment. They work really good too.

We put a pair of the bigger ones in my dads home theater and they were AWESOME in movies. Between his huge sub and those little shakers, it make movies truely engaging.

Movies only though, turn 'em off for music...one exception might be rap..if you consider that music.

-Chad