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pasnu
New member
What exactly is a spectrum analyser? and how do you use it in your workflow?
Massive Master
www.massivemastering.com
It's a meter of sorts that shows the frequency spectrum.
It's nice for calibration and room-shooting. Otherwise, it's fairly useless (although some people are under the impression that they're really important for mixing).
It's nice for calibration and room-shooting. Otherwise, it's fairly useless (although some people are under the impression that they're really important for mixing).
Bobbsy
Boring Old Git
A spectrum analyser is a measurement tool that gives a display of frequency vs. level. Typically, it's like a graph with the various frequencies across the bottom (the "X" axis) and the level markings up the side ("Y" axis). To make this easier to see, here's a spectrum analyser display of a 1 kilohertz tone I generated:
You can see that the tone is centred around 1kHz (no generator is absolutely perfect--this was over a 10 second sample) and that I specified a level of -6dB. The hash at the bottom is the system noise in my DAW. If you look really carefully, you can even see a side lobe either side of the main frequency.
As Massive Master says, it's a diagnostic tool for setup and trouble shooting rather than something I'd ever use in the recording and mix process. When you put actual music through the analyser, it just becomes a useless mess (unless there's a problem like electrical hum for example--but, again, that;s into trouble shooting.
The example of "room shooting" is a good one. Typically, you'd playback pink noise through your monitors and record this with a calibrated test mic. When you look at the spectrum analyser display, you can easily see where there are peaks and troughs compared to the totally flat line the analyser should show--then you can treat the room or EQ the monitors to correct this.
...but, in the mixing workflow? Nope.
You can see that the tone is centred around 1kHz (no generator is absolutely perfect--this was over a 10 second sample) and that I specified a level of -6dB. The hash at the bottom is the system noise in my DAW. If you look really carefully, you can even see a side lobe either side of the main frequency.
As Massive Master says, it's a diagnostic tool for setup and trouble shooting rather than something I'd ever use in the recording and mix process. When you put actual music through the analyser, it just becomes a useless mess (unless there's a problem like electrical hum for example--but, again, that;s into trouble shooting.
The example of "room shooting" is a good one. Typically, you'd playback pink noise through your monitors and record this with a calibrated test mic. When you look at the spectrum analyser display, you can easily see where there are peaks and troughs compared to the totally flat line the analyser should show--then you can treat the room or EQ the monitors to correct this.
...but, in the mixing workflow? Nope.
grimtraveller
If only for a moment.....
It sounds like something from "Star Trek".
Bobbsy
Boring Old Git
Actually, when you're not trying to use it for mixing, it's a very useful device--particularly when you get into working with radio waves.
For example, when you're setting up a bunch of radio mics, a spectrum analyser that goes up into the appropriate frequencies lets you look and see where there's interference from radio or TV stations...or see if one of your mics is putting out lower power than it should be. Or, from my days in TV news, one that gets up to satellite frequencies lets you actually get the dish pointed exactly at the satellite, then adjust your transmit power to the right level.
....and the display looks damn sexy too!
For example, when you're setting up a bunch of radio mics, a spectrum analyser that goes up into the appropriate frequencies lets you look and see where there's interference from radio or TV stations...or see if one of your mics is putting out lower power than it should be. Or, from my days in TV news, one that gets up to satellite frequencies lets you actually get the dish pointed exactly at the satellite, then adjust your transmit power to the right level.
....and the display looks damn sexy too!
bouldersoundguy
Well-known member
A spectrum analyzer is a graph that plots frequency versus amplitude. If your ear is telling you there's some low-mid buildup you might look at a spectrum analyzer to try to identify more precisely what frequencies are building up. It can also be good for precisely identifying the frequency of feedback in a live situation.
A spectrum analyzer is not good for room measurements as it is time blind and makes no distinction between the speakers' natural response and room reflections/resonance.
A spectrum analyzer is not good for room measurements as it is time blind and makes no distinction between the speakers' natural response and room reflections/resonance.
cobaltaudio
New member
Bobbsy
Boring Old Git
You spy correctly....35ish years in the industry, in both Canada and London UK.
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CraigCyril
Banned
The purpose of a spectrum analyzer is to provide a plot or trace of signal amplitude against frequency. The display has a graticule which typically has ten major horizontal and ten major vertical divisions. A spectrum analyzer interface is a device that can be connected to a wireless receiver or a personal computer to allow visual detection and analysis of electromagnetic signals over a defined band of frequencies.
Richie2708
Dis Member
I have to admit that I have never used one, but I always assumed I should. Doesn't it help you find the key frequency of one track so you can EQ out the other tracks to make room for it.....
Maybe using your ears is the more natural way of eq'ing the mix?
Maybe using your ears is the more natural way of eq'ing the mix?
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Greg_L
Banned
Just do an EQ sweep.
Richie2708
Dis Member
Never done that before, research time for me...
Thx Greg
Thx Greg
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Greg_L
Banned
It's very simple, but not always necessary. Don't EQ because you think you're supposed to. Only do it if you need to. When you hear a track or mix and something just aint quite right, a sweep can usually identify the problem. Pull up a parametric EQ plug or use whatever you have. ReaEQ in Reaper is perfect for this. I like to use a narrow width and boost the shit out of it - like 13db so it looks like a spike. Then start low and slowly sweep the frequency up while the track is playing. It's gonna sound goofy, but when you get to the problem area all that mega gain you dialed in is gonna make the problem area really stand out. There, you found it. Now you leave the band on that frequency and back the gain down to cut. Start with a small cut - like 1db and see how it works. You can go deeper or wider from there.
Richie2708
Dis Member
Thx Greg will do that, the amount of time I've spent playing with eq's when just that has happened. I never thought of boosting it all and sweeping to pick out the problem, yet from looking around its an age old technique...
Well you learn something new everyday..thx
Well you learn something new everyday..thx
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stevieb
Just another guy, really.
My experience in pro audio is more live sound, and SA's are used there to more quickly and (sometimes) more precisely ring-out the room. Feedback eliminators have not gained wide acceptance- the criticism is they are too broad in their frequency adjustments and/or difficult or impossible to override, and the next development seems to be manually-adjusted EQ's (whether analog or digital controls) that include a SA- the SA is part of a circuitry that seeks out frequencies that are feeding back, but relies on the operator to make the necessary adjustments to address it. You can ignore the SA's "recommendations" if you want to.
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moresound
Loud Sun Studios
I was given one and it just sits in the rack. Every so often I take a peek at it but that's about it and say "Yeah I know I'm pushing 80Hz and there is the visual"!
Guess it could be greatly used as a learning tool. Everyone should learn what every frequency tone is!
It sure gets a lot of comments from just about everyone who see it though - like that must come in handy, or what the heck is that? etc. etc.
Guess it could be greatly used as a learning tool. Everyone should learn what every frequency tone is!
It sure gets a lot of comments from just about everyone who see it though - like that must come in handy, or what the heck is that? etc. etc.
bouldersoundguy
Well-known member
The real time type are useful for detecting feedback in real time. Analysis that doesn't have a time dimension isn't particularly good for system setup or "ringing out the room".
My cheap Behringer units can do 1/60th octave filters. Typical filters on graphic eqs are many times wider. The filters and their application can be as narrow or broad as the operator decides.
Only when the user doesn't bother learning how to operate their equipment. Usually this results from taking the advertisements that speak of "automatic" feedback control too literally.
Welcome to the 90s. Peavey has been selling graphic eqs with FLS (Feedback Locating System) for years. It has an LED above each slider. The LED lights up showing you the frequency with the most energy at any moment. If you hear feedback you look for the LED indicating the frequency. Dead simple.
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stevieb
Just another guy, really.
Yeah, BSG, everything you say is true and a refinement on my post, although I was shootin' from the hip so I may be wrong about the most-often cited reason for hatin' on feedback zappers. I got two Behri Sharc's, and I like 'em.
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Captain Ego
New member
I just used one for the room back when I was doing sound for a huge-ish rock club. The owner threw it on the rack of tools when he was feeling benevolent one day (also sent me out to buy a dozen SM58s... must have made bank off the college kids or something the previous week, I didn't ask. It kind of helped I guess but he was far more interested in it than I was. Ears are good too (well back then they were). The audience hears what you hear, right? Mostly it just looked really cool and made outsiders watching on think I was doing very complicated things beyond their understanding (my boss included).
rayc
retroreprobate
I've used one occasionally when I needed to find something that EQ sweeping etc, because of my ears, couldn't accurately catch.
I used it to discover a very narrow peak that was consistently in vocal tracks sent to me by my collaborator. I discovered that his signal chain added a very distinct & mix disrupting noise at 15+kh (can't recall exactly now) as well as at around 60hz. By knowing these I was able to adjust filters, paraemetrics, etc to attempt to address the problem (not 100% successfully however).
As my ears could tell there was a problem but not where: I needed an additional tool. I don't use it often but it's a nice tool to have when needed. I didn't get the chance to run an analysis on each part of his chain - wouldv'e been interesting to find out where the problem was/is.
I used it to discover a very narrow peak that was consistently in vocal tracks sent to me by my collaborator. I discovered that his signal chain added a very distinct & mix disrupting noise at 15+kh (can't recall exactly now) as well as at around 60hz. By knowing these I was able to adjust filters, paraemetrics, etc to attempt to address the problem (not 100% successfully however).
As my ears could tell there was a problem but not where: I needed an additional tool. I don't use it often but it's a nice tool to have when needed. I didn't get the chance to run an analysis on each part of his chain - wouldv'e been interesting to find out where the problem was/is.