Frequency Analysis

Post by **Neil B** » Wed May 17, 2006 12:21 am

I've finally finished and mixed a track I started some time ago (A Prayer Before Sleep - I may upload it).
The track contains lots of choirs so there was a constant battle for headroom and separation. I had to do the following:
1: Export midi tracks to audio (of course)
2: Take each track into Wavelab from Cubase. This was to analyse the frequency of each track).
While doing this I noticed that some of the choral samples contained "dirt" (or are they called artifacts?) below 40 Hz.
3: I EQ'd all of the "dirt" out, normalised and re-saved the tracks.
4: Took all tracks back into Cubase for final mixing.

Obviously this is very time-consuming.

So, what is my workaround? I know that Chris (Werner) is aware of my underpowered rig, but I seem to have a couple of options:

a: I could have a frequency/spectrum analyser as an insert in Cubase. I've tried Voxanger Span but it eats my CPU.

b: I could channel each track to a group and have a group insert EQ permanently set to remove low frequencies of all tracks (excluding bass, drums etc depending on the track)
However, there were also "dirty bits" at higher frequencies, so this method would not be perfect.

How would you experts approach this problem?
Is there a spectrum/frequency analyser I could sit in my Scope project?
Is there a way of channeling midi from Cubase through the analyser in Wavelab?

Or do I simply have to go through the painstaking procedure that I'm currently having to do?
I'd prefer to make my "first" export to audio to be the only one required.

Any help would be gratefully appreciated.

_________________
Neil B
Life is not measured by the number of breaths we take, but by the moments that take our breath away.

[ This Message was edited by: Neil B on 2006-05-17 02:36 ]

astroman · Post by **astroman** » Wed May 17, 2006 1:55 am

<a href=http://www.worldless.com/sfp/eq2.html>Wolf's spEQtrum</a> might be worth a look, there's a demo available.
He's on a journey currently, but still can be reached via email.

cheers, Tom

erminardi · Post by **erminardi** » Wed May 17, 2006 2:05 am

http://www.elementalaudio.com/products/ ... index.html [sorry, no more available!]

It's free, a serius tool and low CPU usage.

IMO the best analizer tool is the Waves PAZ... but is so expensive!

[edit] pm me for a backup copy of inspector [edit]
_________________
Scope 4.5 + 2xPulsar II + 1xLunaII + 1xPulsar1 + a lot of devices = Pure Joy

[ This Message was edited by: erminardi on 2006-05-25 06:16 ]

[ This Message was edited by: erminardi on 2006-05-25 06:20 ]

katano · Post by **katano** » Wed May 17, 2006 5:06 am

On 2006-05-17 02:55, astroman wrote:
<a href=http://www.worldless.com/sfp/eq2.html>Wolf's spEQtrum</a> might be worth a look, there's a demo available.
He's on a journey currently, but still can be reached via email.

cheers, Tom

AnalyzerPack for Scope, also from Wolf, is located here: <a href=http://www.worldless.com/sfp/ana.html>Wolf's Analyzer</a>

Use it in a master insert slot in your stm mixer. solo the channel you want to analyze, voilà...

how many dsp's do you have? it's a bit dsp hungry but works fine for me (21dsp system)

greez
roman

[ This Message was edited by: katano on 2006-05-17 06:09 ]

Post by **Neil B** » Wed May 17, 2006 6:03 am

Thanks again for the prompt replies.

I KNOW that I ought to stay patriotic to the "Planet Z" but I've tried Inspector first and it looks like the tool that I need.
VERY low CPU compared to Voxengo Span and working a treat.

I've only spent half an hour with it and have a question already:

I tried it on a wave file that I'd already eq'd to cut out anything below 40hz but on the inspector display it shows a curve from -50 on the "Y" axis down towards my 40Hz on the "X" axis, as if there is something present in there.
Any ideas?

Thanks again for all your help - this should make working much easier.

astroman · Post by **astroman** » Wed May 17, 2006 1:23 pm

well, I suggested Wolf's spEQtrum because it shows the analysis in the background of the eq curve, which is probably very handy - not to forget that Wolf's EQs are really good, imho.

I ran his RIAA curve (just a special application of his 8-band Eq) against the well regarded NAD 1020 phono stage and it was at least on par, if not more transparent (of course I used a less noisy instrument pre-amp and not the Pulsar's input stage).

just for the spectrogram (almost) any native app should do, but the 'proper' tool would remove the unwanted parts of the signal by a convolution process based on arbitrary selections within the spectrogramm.
Such a program exists, I just forgot about the name.

I didn't try to find it back because it's in the 500 Euro range - and half of the amount would probably buy you a perfect sample set...

cheers, Tom

Chisel · Post by **Chisel** » Wed May 17, 2006 2:40 pm

On 2006-05-17 01:21, Neil B wrote:
3: I EQ'd all of the "dirt" out, normalised and re-saved the tracks.
4: Took all tracks back into Cubase for final mixing.

Wouldn't it be much easier and less destructive to EQ the tracks in Cubase?

Peace /
Chisel

ChrisWerner · Post by **ChrisWerner** » Wed May 17, 2006 9:31 pm

Sure it would be easier to EQ in Cubase, but Neil PC is similar to a pocket calculator.
So he had to analyse the track in Wavelab.

Neil, there is no way to route your track(s) to wavelab to get a realtime analyse.

On to the (not removable) rumbles in your tracks. Normally, if you´ve cut away from 40 Hz downwards, there shouldn´t be anything, or?
So I guess your PC produces some noise in that array by itself?
Try to analyse an empty arrangement, drop a analyser on the master bus and have a look what happens there.

I am afraid to say but, buy a new PC!
You will always run into not having enough CPU power, sooner or later. Your songs will grow, getting more complex, mastering is complex. Wasted time can be a killer for creativity.
_________________
Music starts where any language ends 
<a href="http://www.spring-of-sound.de">Spring-Of-Sound.de</a>

[ This Message was edited by: ChrisWerner on 2006-05-17 22:31 ]

Post by **Neil B** » Thu May 18, 2006 12:09 am

Some more great replies here and I thank you all for them.
Let's have a look at them in order:

Astroman - you destroyed my brain! I'm really not that technically minded but I can sort of see where you're coming from. You know what it's like when you write a piece of music - you want it burnt to CD so you can move onto the next track.
I've never given myself enough time to LEARN and that is the road I'm starting to travel along now. I'll allocate some time for composing and some time for learning the techy mixing stuff more.
Thanks again & I'll add your comments to my growing library of notes marked "For future use"

Your help is much appreciated.

Chisel - yes I agree with you but that was the reason for this post.
It was only after I'd exported my midi choir tracks to audio and started mixing that I could "hear things" that shouldn't have been there. I couldn't track them down properly without analysing the waves with a frequency analyser and to do that I had to use Wavelab.
Having found the "dirt" in wavelab, it made sense to eq them on the spot, re-save and then use the clean tracks back in Cubase for the final mix.
Of course the opposite argument is true too - I could have put all the tracks into a Wavelab montage and mixed it all there, but it's what you're comfortable with sometimes.
Now, with Inspector, I should be able to spot problems and (for instance) EQ them at source, in midi, to get a first pass, clean audio track.

Chris, I take your point and thanks for the help again, but I've since done a bit more research and perhaps you, and others can help.
The track in question (A Prayer Before Sleep) is one that I spent all this time on, getting the best I could for the mix.
I've looked at the MP3 in Wavelab and using the 60 band spectrum meter it is completely clean below 40Hz.
When I look at the same track in Cubase using "Inspector" as an insert, it shows a curve below 40Hz.
As you can imagine, this makes me wary of Inspector at this stage.

So, what I'm going to do is upload this track. I don't think anyone will like it, but put a link to this topic in the notes.

If anyone has Wavelab and Inspector and is prepared to have a look at the MP3 for me in both, I'd be interested in your views.

Thanks to all

(BTW Chris, I'll download your latest later today after I've uploaded "Prayer" - must get broadband - 31200 is a rubbish speed)

ChrisWerner · Post by **ChrisWerner** » Thu May 18, 2006 1:26 am

Well my analyzer shows a "heavy load" from 0>62 Hz at -32db average. So the inspector seems to work correct.
These loads at the low end costs a track lots of energy that lacks in the final mastering.

Do you use an EQ on the master channel, too?
You should, to cut the lows before you compress maximize or whatever.

My experience and guess.
Most of the sounds from the atmosphere produces very heavy loads at the low end.
I had problems on that with atmosphere,too.

An atmosphere played at low notes means an EQ to decrease the low end.

Post by **Neil B** » Thu May 18, 2006 1:32 am

How strange then that it doesn't seem to show anything below 40 in the Wavelab 60 band analyser - I'm confused!
Thanks Chris

ChrisWerner · Post by **ChrisWerner** » Thu May 18, 2006 1:47 am

Well, wavelab shows me the same load.
Wavelab 
<img src="http://www.spring-of-sound.de/Pics/wavelab.jpg"></img>
 
PAZ 
<img src="http://www.spring-of-sound.de/Pics/paz.jpg"></img>

Post by **Neil B** » Thu May 18, 2006 2:19 am

Okay, I'm starting to get somewhere with this now (and learning a lot too)

In the Wavelab 60 band analyser, nothing shows in the bars for me below 40Hz

When I use the FFT meter in Wavelab, I can see the frequencies below 40HZ - thanks Chris - you're correct of course.
I'll use the FFT metere in future.

So this now begs another question.
How can I remove these frequencies completely.
In wavelab I've put an eq across it but this only reduces by -18Db. If I remember correctly, the one in Cubase Dynamics will reduce by -24Db.
So how do I get rid of the rest? Is there an eQ plug in that will reduce even more?

At least it tells me that I can trust the "INspector" when I use it in Cubase.

Can't you tell how ignorant I am

_________________
Neil B
Life is not measured by the number of breaths we take, but by the moments that take our breath away.

[ This Message was edited by: Neil B on 2006-05-18 03:21 ]

ChrisWerner · Post by **ChrisWerner** » Thu May 18, 2006 2:59 am

A graphical EQ qill be best, where you see what you do.

Use an EQ with one band set to high pass at freq 40Hz or where ever you want with the largest Q setting.

<img src="http://www.spring-of-sound.de/Pics/highpass.jpg"</img>

Have to prepare myself for my study lessons and concert later. Read you tomorrow again.

Chisel · Post by **Chisel** » Thu May 18, 2006 8:49 am

This is an interesting thread. I use Inspector as my spectrum analyzer. I usually drop it into the master track and solo the track I need to analyze. I've found some peculiarities with Scope by using this method. I notice that the PEQ4 doesn't kick in until I load a preset. If i just select one point and assign it to high-pass, it doesn't do anything. When I load the appropriate preset, then it works.

Peace /
Chisel

symbiote · Post by **symbiote** » Thu May 18, 2006 11:24 am

Chisel, this is because when you load the PEQ4, there is no band defined. You need to double click on the graphic display to create one (I think there is a button that'll let you add one too), and then configure that band to your liking.

wolf · Post by **wolf** » Thu May 18, 2006 8:04 pm

well, the graphics indicate, that your low frequencies of the left+right channel aren't correlated (in phase) to each other. Perhaps that's your main problem. You should see this in inspector's correlation graph, if you put a 300Hz high cut before it.
To have a fast check with this, I've put a switchable high cut into my correlation meter (part of the analyzer pack), that doesn't affect the sound, you hear.
You should check, if there's a synth, which emits that uncorrelated low sound (by soloing every instument one after another) and use a low cut on it to get rid of it.

rock on
Wolfgang

_________________
<a href="http://www.worldless.com/sfp">wolf audio design</a>
<a href="http://www.worldless.com">worldless productions</a>

[ This Message was edited by: wolf on 2006-05-18 21:09 ]

wolf · Post by **wolf** » Thu May 18, 2006 8:11 pm

IMO the best analizer tool is the Waves PAZ... but is so expensive!

no, the best tool available is still pinguin audio meter.

wolf · Post by **wolf** » Thu May 18, 2006 8:13 pm

... beside mine of course

AndreD · Post by **AndreD** » Fri May 19, 2006 1:28 am

just a nice tool:
http://www.sillanumsoft.com/