Subject:Flat response

Posted by: TRS

Date:11/18/2001 5:20:56 PM

Is there any function in SF 4.5 to make a file have flat frequency response? That would be preety cool, since is'nt that one main objective we are trying to achieve in the mastering process. How can you tell what the freq response is anyway? I've checked out the spec analysis feature and found it to be very confusing.

Subject:RE: Flat response

Reply by: Rednroll

Date:11/18/2001 5:53:57 PM

You don't want flat frequency response of your files. What you want is flat frequency response of the devices that are playing back your files. Things like your speakers, soundcard, mixing board, amplifier. If these devices have flat frequency response then you will be truly hearing the correct way your file sounds (ie the playback devices don't color the sound of your file.)

As an extreme example of not wanting flat frequency response on a file, let's say you are trying to create a voice that sounds like it's talking over a telephone. This is done by increasing mid frequencies around 1Khz and then cutting other high and low frequencies. Now if you make that file have a flat frequency response you just got rid of the effect the file was originally suppose to have. The same will happen to a music file. You totally mess up the impact that the song was trying to create.

Subject:RE: Flat response

Reply by: TRS

Date:11/18/2001 7:57:47 PM

Well then what is the spectrum analysis used for
except for being cool to look at?
Do you use it and for what?

Subject:RE: Flat response

Reply by: Rednroll

Date:11/18/2001 8:17:11 PM

A spectral analyzer is very useful when you are mastering. I don't use the SF spectrum analyzer because I find it useless for how I'ld like to use it. I use a spectral analyzer called "SpectralLab". When mastering I have clients bring in CD's that they know sound well mastered and are similar to their music. I run their CD reference through the Spectral analyzer and see how the EQ curve is. I then capture that curve, and I then EQ their music so that it matches that curve. So if the curves are the same, and the client knows their reference CD sounds good on their home stereo, then their music will be the same, because the frequency content is similar. This is also how Steinberg's plugin called Free Filter works. It copies the EQ curve of a reference and then applies that curve to your song.

Also, a spectral analyzer is nice to find a particular unwanted sound. For example, I had a client bring in a piece to be mastered and they complained that everytime the bass played it made an annoying sound. I ran the mix through the spectral analyzer and found that the bass had a harmonic which caused a spike at 12Khz. I was able to EQ that 12Khz peak out because I could see exactly what frequency it was at and how wide the bandwidth was. Also in doing so I didn't effect the rest of the mix. Thus it took the guess work out of eqing, I was able to pick the exact frequency and bandwidth and amount to decrease.

Subject:RE: Flat response

Reply by: VU-1

Date:11/18/2001 9:24:26 PM

What I did was gather together a bunch of major label CDs & picked songs of different styles that sounded great and made myself a Mastering Reference CD-R (a compilation CD, if you will). I also ran SF Spec Anal. on each tune and did a print screen of the FFT graph and saved each one on my hard-drive so that I could go back & reference them at any time. (SF should make it so that we can save the graph).
While I'm doing my mastering, I periodically run an FFT of the song I'm working on & compare it to the FFT of a song from my Ref. CD that is of similar style.
One thing that you have to keep in mind is that the resolution of the FFT graph is somewhat coarse. What this means is that small changes in EQ or Compression settings are readily heard but not so readily seen on the graph. An FFT may be very close visually to that of another song, but may sound noticeably different. Therefore, its also a VERY good idea to A-B your mastering against a GOOD CD so you can hear where you stand.
The key is: use the Spec. Anal. as a very helpful tool, but use your ears as the definitive judgement.

JL
OTR

Subject:RE: Flat response

Reply by: Rednroll

Date:11/19/2001 3:21:44 PM

I totally agree with OTR. BTW OTR, have you tried spectral Lab? I do exactly what you mentioned with spectral lab. The cool thing about spectral lab is that you can store 4 EQ curves as a reference(no need for the capture screen). The Curve appears on the screen while your input signal bounces up and down and you can see A and B mixes simultaneous on the same logrithmic scale. I've saved 4 reference graphs 1 for Rock, 1 for Techno, 1 for Hip Hop and 1 for new reference CD's and I turn that reference on as a starting point for new songs I'm mastering.

The waves PAZ Analyzer is also an awesome spectral analyzer, but I don't think they ever released a PC version. That's how I found Spectral lab to replace the tools when I moved from mastering on Macs to PCs. It has worked out awesome for me. I can't even use the sonic foundry one, there's too many bouncing dots.

Subject:RE: Flat response

Reply by: TRS

Date:11/19/2001 3:49:42 PM

Who makes Spectral Lab And where can I get it?

Subject:RE: Flat response

Reply by: Rednroll

Date:11/19/2001 5:38:36 PM

Spectral Lab is made by a company called "Sound Technology Inc.". I don't know what their web address is, or if there's been updates, or if it's still available. I got this piece of software almost 3 years ago and have never found a need to update it, so I don't know much else than that.

I would like to know if you find any info out about them though.

Subject:RE: Flat response

Reply by: VU-1

Date:11/19/2001 9:05:41 PM

Red-
The one thing that I REALLY wish I could do w/SF Spec. Anal. is to adjust the responsiveness of the curve while its monitoring playback (get rid of all those little bouncing dots as you call them). Know what I mean? - show an average of the freq. response curve instead of just the instantaneous readings.
That reminds me of another feature I need - the ability to view the curve while doing a real-time preview (plug-in chainer) so I can see how the graph is responding to different parameter adjustments - before I process the file.
Will Spectral Lab do either of these?

JL
OTR

Subject:RE: Flat response

Reply by: Rednroll

Date:11/20/2001 11:24:50 AM

Yes, Spectral Lab will do both of these. You can change how responsive it is. This is my favorite feature and you can also adjust the amount of FFT's, so you can take the resolution of the spectral analysis to what you need. You can pick the type of Smoothing you want there's 9 types (Hanning, Blackman, Triagular,Kaiser, uniform..etc.) So no stupid dots bouncing around, just nice EQ Curves. One note, I'm not sure how or if Spectral Lab works with playback from a Wave. I'm sure it does, I've just never used this function with my process of mastering. It's a stand alone program, which I use for a realtime input device. I do most of my mastering using my TC Finalizer and adjust the EQ and Multi-band Compression using that and I can see the effects with the realtime input of Spectral Lab analyzer. After I got those parts hammered to perfection then I just use sound forge to record the song in, run additional plugins if needed, check for DC offset and then Normalize using peak level normalization. After that I do a midi dump from the finalizer into my favorite sequencer and make some notes on plugins I used in the sequencer and Walla..."Total Recall mastering". Burn a CD and have a nice day.

Subject:RE: Flat response

Reply by: beetlefan

Date:11/20/2001 1:11:57 PM

You can use EQ but you need to have the original, flat original file for reference. Since i'm assuming that your soundcard or input device is not up to the task I don't see how you can even accomplish this.

In other words, there is NO magical device in SF or any other editor or hardware that will accomplish this. You're going to have to either live with what you've got or spend some $$$ on better gear.

Subject:RE: Flat response

Reply by: CDM

Date:11/20/2001 2:57:08 PM

http://www.soundtechnology.com/download-center.htm

Subject:RE: Flat response

Reply by: Rednroll

Date:11/20/2001 4:22:28 PM

If you would have read my original post beetle, you would realize that you don't want flat response on your files. Your ears don't work on a flat frequency response, thus your music shouldn't be flat. Thus the original post had some confusion on wanting to achieve "Flat Response", which hopefully we all helped clear up.

Again more brilliant advice from the beetle. Suppose if you had flat response on the "dither noise" located in the "Sensitive" parts of the "Musical spectrum", then your mastering would drastically improve, if you go out and spend the money so that your gear is up to the task. Wow....now does this make sense to anyone else out there?

Subject:RE: Flat response

Reply by: joetbn

Date:12/6/2001 3:48:00 AM

Flat compared to what? if you are recording pink noise you might want what looks like a flat response, no music I have ever heard or ever want to hear looks like that. You look for "flat" responce in a pair of speakers or in a mic for some aplications. A playback system should be"flat" to give the best represintation of what the sound engineer wanted, but as the engineer mastering the prosess, you get do decide based on your own musical taste what you want the mix to sound like. To do that you need a room and a monitor system that is absloutely flat. as Bob Ludwig (probably the best person alive at mastering recordings) said: "if you can't take the room out of the mix, you can't take the mix oput of the room" Spend more money on room treatments, speakers and amps than software.