Lyrics & Knowledge Personal Pages Record Shop Auction Links Radio & Media Kids Membership Help
The Mudcat Cafemuddy

Post to this Thread - Sort Descending - Printer Friendly - Home


Tech: Frequency Slotting for Recording.

Acorn4 21 Jun 09 - 05:04 PM
pdq 21 Jun 09 - 05:29 PM
Nick 21 Jun 09 - 06:42 PM
Nick 21 Jun 09 - 06:48 PM
Nick 21 Jun 09 - 07:25 PM
Darowyn 22 Jun 09 - 05:04 AM
mattkeen 22 Jun 09 - 05:31 AM
Nick 22 Jun 09 - 06:19 AM
Darowyn 22 Jun 09 - 10:30 AM
Acorn4 22 Jun 09 - 11:48 AM
treewind 22 Jun 09 - 11:54 AM
Grab 23 Jun 09 - 10:55 AM
Share Thread
more
Lyrics & Knowledge Search [Advanced]
DT  Forum
Sort (Forum) by:relevance date
DT Lyrics:





Subject: Tech: Frequency Slotting for Recording.
From: Acorn4
Date: 21 Jun 09 - 05:04 PM

This is a bit of a technical one. I've done quite a bit of home recording, but have never actually done any sort of course on how to do it.

I've gradually been getting more ambitious and including more instruments such as hurdy gurdy, highland pipes and accordion. It tends to end up a bit of a mush with all the instruments and I've been told that you can separate the instruments by a technique called "frequency slotting", which means giving the instrument a boost on the EQ in the centre of its frequency range. For instance, acoustic guitar, apparently centres at around 800Khz.

Is there a source anywhere which gives these frequencies for folk instruments.I've tried online and can only find stuff which is very complex or charts for orchestral instruments.


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: pdq
Date: 21 Jun 09 - 05:29 PM

Perhaps you can borrow a truly fine microphone and see if the separation of instruments gets better.


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Nick
Date: 21 Jun 09 - 06:42 PM

I found the following article good - E Q Primer

You might also try the local library. Ours had at least half a dozen good books on sound and mixing that were really helpful.

I also know little about this as self taught and learning a little bit by bit - but this is something of what I have learned.

The first thing is you may add clarity to a mix by panning instruments to different places and treating it as a 3d thing so that they don't fight in space as well as frequency.

Most of what I read suggested cutting rather than boosting was the key. You increase definition of instruments as you cut out the frequencies where they tend to compete - guitar, bass and keyboards and parts of the drumkit all do battle in the same frequency bands and so make each other indistinct and dull. By cutting and boosting a bit it will help to distinguish them - there is a short section about 'Complimentary Equalization' in that article which is what I think you refer to and it gives a couple of examples.

Do you have access to a parametric equaliser? It's worth playing around with one and see what it does. Usually you can hear the difference as you change the settings as you listen - you can often hear clarity occurring right in front of your eyes/ears(?).

An example - I use a Zoom H2 to record live gigs (some with a 6 piece band of sax/acoustic/electric gtrs/bass/drums/vocals) by popping it out front of the band somewhere. Once I download it I usually apply a parametric EQ with the settings at the bottom of this paragraph (I call it chopmud2) and it takes out a lot of the indistinct mud in the recording and seems to help. It was based on trial and error with my ears but seems to work to my ears - if I turn the effect off it resumes its former muddy sound. Why it works or whether it is a good or bad thing or 'right' I don't know!

There is a 10db CUT at a central frequency of 240hz with a Q of 3 (band type Peak).
There is a 5db boost at 2875hz with a Q of 3 (band type Peak).
There is a 8db boost at 9000hz with a Q of 3 (band type High Shelf).

Someone will now probably tell me that's all wrong but it works for me.


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Nick
Date: 21 Jun 09 - 06:48 PM

Another decent (and understandable) article here - The Art of EQ


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Nick
Date: 21 Jun 09 - 07:25 PM

Instrument frequencies
Lots on google


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Darowyn
Date: 22 Jun 09 - 05:04 AM

Nick is correct when he says that the EQ is used to cut frequencies which mask other instruments, though the general idea of multi band EQ is to leave the signal at its original total level- so that the overall effect is neither cut nor boost, when taken across all frequencies. Cut 6dB here, boost 6dB there. (that is a lot, by the way- more subtle is usually better)
One mistake which is often made is to listen to individual instruments and tweak the EQ until each one, on its own, sounds how you think it ought to. Mixing them all together, the result is always overlapping frequencies, and a mushy lack of separation. The guideline is that you don't know what the individual instruments should sound like until you have heard the ensemble.
Actually there are several ways of achieving separation. Instruments can be heard as separate if they are separated by:
-Space: position in the stereo field, or sometimes in the reverb soundfield- if it sounds further away, its not the same instrument!
-Tone: by natural or processed EQ
-Pitch: you never confuse a double bass with a piccolo
-Attack: an instrument with a percussive attack like a guitar, will sound separate from one with a breathy attack like a flute, even when playing in unison.
-Time and rhythm: two instruments playing one after the other, call and response style, or one instrument playing quarter notes (crochets) will sound distinct from another playing sixteenths (semiquavers).
Hope this helps,
Cheers
Dave


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: mattkeen
Date: 22 Jun 09 - 05:31 AM

Sound on Sound is a great mag and the forum is invaluable for this sort of thing.
Sculpting sound to leave holes for other instruments is only one technique and may not be the one you want anyway.
Many folk instruments operate in a relatively similar frequency range and can often mask each other.


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Nick
Date: 22 Jun 09 - 06:19 AM

Instrument frequency 2 - another useful wee chart with fundamental frequencies of quite a lot of instruments.

As an aside, if you know the range of the instrument you can work out your own chart as the fundamental frequencies will be the same - a 440 A is a 440 A regardless of instrument. Most of the charts only cover the fundamental range of the instruments rather than what part of the overtones make a huge difference to the sound. I presume that is something down to the shape of the wave / nature of the instrument that determines it and that is way beyond my limited knowledge.

The other thing I have heard mentioned is to chop everything under (I think) 40Hz with a high pass filter.


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Darowyn
Date: 22 Jun 09 - 10:30 AM

Cutting sounds below 40Hz is not as brutal as it sounds. Although, in theory, audio range goes down to 20Hz, in practice a pure single frequency sine wave at 40Hz is very difficult to hear by most people, even the young and fit. A double bass plays fundamentals at that frequency, but if you were to filter out the fundamental, and just hear the overtones (harmonics) the bass would still sound to be at the correct pitch.
Your brain can tell what the fundamental frequency should be. (Law of the missing fundamental)
We are so insensitive to low frequencies, that is it very easy to have very high levels in the low bass without your knowing. If you use compression, however, the compressor will take its cue from the loud, but inaudible, bass signal, and the result will be a recording that looks loud when you see the waveform, but sounds quiet.
Matt Keen has my support in recommending Sound On Sound. Paul White and Hugh Robjohns are both friends and neighbours of mine.
Where did you think I learned all this, well enough to teach it for fifteen years?
Cheers
Dave


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Acorn4
Date: 22 Jun 09 - 11:48 AM

Thanks for all that so far - it all sounds mightily useful.


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: treewind
Date: 22 Jun 09 - 11:54 AM

Two suggestions:
(a) your ears are the best guide (though some knowledge of what various frequencies sound like will hep you to get in the ball park)
(b) Instead of boosting some frequencies, try cutting others.
(c) don't overdo it.

Sorry, that's three. I'll stop now...
Anahata


Post - Top - Home - Printer Friendly - Translate

Subject: RE: Tech: Frequency Slotting for Recording.
From: Grab
Date: 23 Jun 09 - 10:55 AM

If you need to do this really drastically, chances are that your arrangement is probably the culprit. If this blend of instruments in real life would end up as a mess of noise, then it's not going to work as a recording either.

Graham.


Post - Top - Home - Printer Friendly - Translate
  Share Thread:
More...

Reply to Thread
Subject:  Help
From:
Preview   Automatic Linebreaks   Make a link ("blue clicky")


Mudcat time: 19 June 10:12 PM EDT

[ Home ]

All original material is copyright © 1998 by the Mudcat Café Music Foundation, Inc. All photos, music, images, etc. are copyright © by their rightful owners. Every effort is taken to attribute appropriate copyright to images, content, music, etc. We are not a copyright resource.