Phase Cancellation / Gain

[Donna]

Hey all~

If too many low frequencies can cancel each other out, is the reverse true? That too many high frequencies can cancel one another out, resulting in mud or boom?

Also...does the gain - or can it - fit into the above somehow...if the gains are riding high on too many things, is there a predictable net effect?

Any principles are helpful, thanks.

[Prometheus]

Hey all~

If too many low frequencies can cancel each other out, is the reverse true? That too many high frequencies can cancel one another out, resulting in mud or boom?

Also...does the gain - or can it - fit into the above somehow...if the gains are riding high on too many things, is there a predictable net effect?

Any principles are helpful, thanks.

99 percent of your frequency problems are going to be below 1KHz... It's usually standing waves and the harmonics form the low fundamentals that cause mud and boom, or badly miked instruments...

Subtractive EQ on the low mid range usually greatly improves a sound...

[john]

Hey Donna

Prom is right. Cancellation does happen at higher frequencies, but not to the extent that it causes much of a problem, at least you have more room for manouver and issues tend to be less noticable. By poking holes using EQ to allow instruments to cut through you are effectively managing any higher frequency clashes. At higher frequencies it doesn't tend to be cancellation causing drop out, more a muddy indistinct sound.

Yes individual channel EQ gain does affect the drop out, but the problem is fundamentally the overlapping frequencies. The bass range is really sub 400 Hz. If you consider the range as 400 Hz, there's a good chance of overlap. Say mid has a range of 1600Hz and Hi at 18KHz (not quite right, but close enough to illustrate the point I hope).

Cheers

John

[Prometheus]

Yes individual channel EQ gain does affect the drop out, but the problem is fundamentally the overlapping frequencies. The bass range is really sub 400 Hz. If you consider the range as 400 Hz, there's a good chance of overlap. Say mid has a range of 1600Hz and Hi at 18KHz (not quite right, but close enough to illustrate the point I hope).

Cheers

John

Absolutely... Certainly in the room I work in, I've never worked on any master yet that didn't sound clearer and warmer after a cut around 250Hz and a cut around 440Hz... Apart from those two points, it's generally just a smiley curve cut of between 1 and 2dB with a very wide Q

[Bitstream]

Adding any range of frequencies together can always result in what is called "beat frequencies". And some of these frequencies can be quite low. Speaker systems, however, can be classified in 2 grades for simplicity; high freq and low freq. low freq are driven by the woofer / base bin / the large cone. So 100Hz + 150 Hz will yield a meaty 50 Hz hum through the base bin. Not very nice. The same beat frequency can be created by adding 10000 Hz and 10050 Hz. But this time the beat frequency is played out of the tweeter (much lower power and also very poor response at low freq). So you wont hear it at all.

Incedently, the pre-amp for the headphone socket on devices like iPods etc, use beat frequencies to give you base. The little plugs that go in your ear are too small to deliver true sub-1000Hz frequencies, so they choose 2 frequencies beyond the audible hearing range, add them together, and the result is a "beat" of the low frequency.

Edited December 6, 2006 by Bitstream

[Donna]

Subtractive EQ on the low mid range usually greatly improves a sound...

What's subtractive eq mean? "Less"?

Hey Donna

Prom is right. Cancellation does happen at higher frequencies, but not to the extent that it causes much of a problem, at least you have more room for manouver and issues tend to be less noticable. By poking holes using EQ to allow instruments to cut through you are effectively managing any higher frequency clashes. At higher frequencies it doesn't tend to be cancellation causing drop out, more a muddy indistinct sound.

Yes individual channel EQ gain does affect the drop out, but the problem is fundamentally the overlapping frequencies. The bass range is really sub 400 Hz. If you consider the range as 400 Hz, there's a good chance of overlap. Say mid has a range of 1600Hz and Hi at 18KHz (not quite right, but close enough to illustrate the point I hope).

Cheers

John

Drop out...meaning ____?

OK, you're losing me on overlapping frqu being a problem. But first: did you mean this: "the bass range is really sub 400 Hz" but if someone "consider the range as 400Hz there's a good chance of overlap." As in, if the person recording/mixing is mistaken about the frq of any given range, more chance of overlapping?

[john]

Drop out meaning cancellation resulting in a nte voulme reduction at a given frequency. Also you can sometimes get a volume pulsing effect.

Overlapping frequencies from multiple channels in a mix. So for example a bass guitar and a cello part. Weirdly enough when you turn the cello up because you can't hear it properly, the overall volume goes down for some notes. This is due to phase cancellation

[Donna]

OK - then phase cancellation is def. happening w/ my project.

So...the overlapping of frq means simply more than one instrument "competeing" in its frq range, for that frq range?

[john]

yeah sort of. Best described with a diagram. I'll knock something together.

[john]

Hey Donna

Just a quick (very) scribble...

Let me know if you need any more detail.

[Donna]

Mon Capitaine, I do not have permission to use that feature (and I am logged in )

[john]

you don't have permission to view it? weird. I'll look into it

[Prometheus]

What's subtractive eq mean? "Less"?

That's affirm...

[Donna]

OK...so less gain there, Prometheus? Or get the H outta that freq. range altogether (low mid)?

99 percent of your frequency problems are going to be below 1KHz... It's usually standing waves and the harmonics form the low fundamentals that cause mud and boom, or badly miked instruments...

Subtractive EQ on the low mid range usually greatly improves a sound...

Edited December 15, 2006 by Donna

[Donna]

Adding any range of frequencies together can always result in what is called "beat frequencies". And some of these frequencies can be quite low. Speaker systems, however, can be classified in 2 grades for simplicity; high freq and low freq. low freq are driven by the woofer / base bin / the large cone. So 100Hz + 150 Hz will yield a meaty 50 Hz hum through the base bin. Not very nice. The same beat frequency can be created by adding 10000 Hz and 10050 Hz. But this time the beat frequency is played out of the tweeter (much lower power and also very poor response at low freq). So you wont hear it at all.

Incedently, the pre-amp for the headphone socket on devices like iPods etc, use beat frequencies to give you base. The little plugs that go in your ear are too small to deliver true sub-1000Hz frequencies, so they choose 2 frequencies beyond the audible hearing range, add them together, and the result is a "beat" of the low frequency.

Well, is there a general remedy for this, Bitstream?

I assume the speaker info applies to not just monitors? I am monitoring once removed - of necessity currently - mixing via headphones, listening to the mix on several pairs of speakers (car, boombox, etc;).

[Donna]

I just needa drink and to trust my ears.

- but don't stop replying, ok -

The whole song has to be done again...that I've known, and not just for tech glitches. But sometimes, I just don't wanna know it, much less learn how to do it. How many times, done again, who knows? Gotta try to do right by the song. I do not NOT NOT recommend trying to play everything and do everything alone.

Unless you're Hari!

[Prometheus]

OK...so less gain there, Prometheus? Or get the H outta that freq. range altogether (low mid)?

You just have to trust your ears on how much gain to subtract, and what Q to set...

[Donna]

It's been a few months now since I quit playing with this toy (the song recording).

Phase cancellation was the last straw

Last night I had a desire to listen to the master, which I've yet to find, but did listen to some mixes. And I think now I am too hard on myself. I'd forgotten how far I'd got with it! The song deserves to be tried again and simply done, to my best capability. But I don't yet know if I will follow through.

It seems a victory tho, to want to play with my toy again - or at least look at it.

[Nightwolf]

it can be frustrating, keep trying

[john]

Hey

Each time you go through the process you will learn something Donna, hopefully quite a lot of things. Don't be hard on yourself. Before you started this you didn't have a recording of your own. Now you do. Getting the right balance of perfectionist and pragmatist is always tricky...

Cheers

John