Using fundamental frequency as rolloff point

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UberGawkman

UberGawkman

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Hey, I was wondering if this makes sense to do..... would using the fundamental frequency of an instrument be a good rolloff point? This is what I mean:


You hear stuff like, "Roll the bass guitar off at 80 hz," "Roll the bass guitar off at 70hz", etc, etc.

Well, let's say your bass guitar is tuned to E. E is the lowest possible note you can play on the bass guitar. The "E" up from a440 is 660, I believe. Divide that in half, 330. Divide that in half, 175. Divide that in half, 87.5

So your rolloff point would start a little below that, maybe 85 or down to 80hz. With guitar, you would start your rolloff point a little below 175, say 160-170hz, etc.

You're tuned to drop D. This would make your rolloff point on bass guitar about 73hz, so maybe rolloff at 70hz. On guitar, rolloff a little below 146hz, like maybe 130-140hz.

This way, when you play the lowest note on the instrument, you're not prematurely cutting off the fundamental note.


Thoughts?
 
Not a bad idea, except you have your fundamental notes an octave higher than they actually are.....E on guitar is 82.something Hz, half that for Bass guitar. It only SOUNDS like the octave higher is the fundamental on many string instruments because of:

1 - Strong 1st overtones (read up on overtone series)

2 - Fletcher/Munson Relative Loudness Curve findings about our ears ability to PERCIEVE different frequencies that are all at the same sound pressure level differently. Meaning, your ear is more sensitive to a 160Hz tone than a 80Hz tone if they were at the same exact volume. The relation to the percieved volume will change depending upon the SPL in question. As the SPL gets louder, the difference of percieved volume is less, and lower volumes, it is more of a difference. Lower frequencies just need more volume to be PERCIEVED as loud as frequencies that are higher than it. The Fletcher/Munson Relative Loudness Curves illstrate just how much louder or quieter all frequencies would need to be than a 1KHz tone at any certain dB. It is VERY GOOD to understand these curves!!!

Try applying a high pass filter at 40Hz for a bass, and 80Hz for guitars. You can go higher IF the song tempo is "uppity" (chances are at faster volumes that you will not distinctly hear the bass that well, and it will eat up a lot of your overall volume level) For slower songs, you might not want to chop any of the resonance off that goes any lower that what I suggested there. You also need to be aware that just because the fundamental is those notes, the wood of the instrument can create lower frequencies, and of course a guitar amp speaker box can too. The room can create lower frequencies too. You just need to be careful that you don't chop off resonance you MIGHT want with a High Pass Filter. Otherwise, go to town.

Eddie
 
sonusman said:
2 - Fletcher/Munson Relative Loudness Curve findings about our ears ability to PERCIEVE different frequencies that are all at the same sound pressure level differently. Meaning, your ear is more sensitive to a 160Hz tone than a 80Hz tone if they were at the same exact volume. The relation to the percieved volume will change depending upon the SPL in question. As the SPL gets louder, the difference of percieved volume is less, and lower volumes, it is more of a difference. Lower frequencies just need more volume to be PERCIEVED as loud as frequencies that are higher than it. The Fletcher/Munson Relative Loudness Curves illstrate just how much louder or quieter all frequencies would need to be than a 1KHz tone at any certain dB. It is VERY GOOD to understand these curves!!!
Eddie
Click to expand...


Hence the reason we "hear the flattest" at about 80db volume (which still isn't very flat)?

Reminds me of the days back in concert band. I was a trumpet player. The band director would always encourage the trumpets to play quieter (boo...) and the lower instruments to play louder. Now I finall understand why trumpets are "louder instruments"... because the frequency range they reside within are mainly the ones our ears are most sensitive too. That, and the fact that when we play, we're not a bunch of wusses (whimpy French horns!!!) :D :D :D
 
Hey Ed, I've seen it a ton of times, but do you know a link to a graph of the Fletcher/Munson curve so I can print it out and study it more clearly?
 
Another thing to consider is that all filters have phase and transient distortion associated with them. For High Pass and Lo Pass filters most distortion occurs in the region around the corner frequency. Also the higher the order (6dB/oct, 12 dB/oct, 18 dB/oct,...) of the filter or the higher the Q, the more phase and transient distortion there is.

Setting the corner frequency 1/2 octave lower than the lowest note might be a good idea.

barefoot
 
Damn Ed!!!

You beat ME to it this time!!

It seems like yesterday when we had this same frequency discussion.....

...and no - I still can't sing down to 80Hz.... ;) :D

zip >>
 
I dont roll off bass gutar at all. If good recorded, thru DI box, and if instrument and player are fairly good, i just balance it with some corrective EQ - cut around 315-350 Hz, 3-5 dB, Q=1.
Then if it need some presence, boost hi-shelf from 3 kHz 2-4 dB.
If it is still too ponderous, cut 80-120 Hz 2-3 dB, Q=1
Compress with ratio 2.5:1, attack 20-25 ms, release 40-80 ms, hard knee and make-up gain 1-3 dB if needed to smooth out, depending on style; lower threshold until it start cutting peaks.
It sounds great and defined on hi-fi speakers, and natural rolloff of small speakers make low cut unnecessary.

Excuse my english, ;) Igor
 
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