PlanetZ forums - scopeusers.com

Yogimeister, you can pass a white noise signal through the same chain (the Control Room device can generate this).

Then take a look at the output in the Frequency Spectrum (FFT). If you looked at the white noise directly, it should look like a straight horizontal line in the graph.

When you look at your signal, you should be able to tell if it was rolled-off, like a precise model might do, or if there were phase issues, in which case you'll see some notch filtering happening. The combination of a phase shifted signal and the source material at a given moment can make this sound like rolled off bass, or highs (comb filtering).

Then at least you would see what is happening, and not need to guess.

garyb wrote:i don't see why you'd want to use either limiter for a mix like that, but that's just me. those devices are more suited to individual tracks, imo.

i'm not sure i'm hearing the problem on my internet computer's playback system.

1) Limiters ? Compressors ... no ?

2) I put them on the master for two reasons:

1.
a. To add "Glue" compression to the mix using one or several comps
b. To "soft limit"/"Hard compress" the peaks before hitting the limiter (I make dance music - and in any case - I always have a limiter at the end of the chain)


** What would you different ? what do you guys use to achieve the above results ?


2.
To test the spectral change on a full spectrum (full mix) instead of trying to pinpoint the change to a single "spectrumly sparse" track






Secondly,

I ran some white noise tests (using the Modular NoiseOSC) (in mono setup and stereo setup)

pics:
Up to Down: Dry, MultiFX, 2A, 660
Left to right: Mono noise to stereo output, Dual Mono noise (stereo), 1/16th loop of program material
I dont see anything I can put my finger on - but I DO think I hear sonic differences as in the audio clips I posted above (Please listen to them with good headphones / monitors and notice the overall spectral depth/height and extreme lows and highs)
For me, in front of the studio speakers - its as if energy is taken from the spectrum that hits your bottom throat and moves to the upper throat/lower nose area .... If you get what I mean ...

P.S.

I ran White noise via HPM control pack and got this peculiar output .... (There is also a reference spectrum added)

What are you trying to achieve with these noise tests? We use noise to check the acoustics of rooms.
Why you don't just try a phase cancellation test?

Also you should use tools that you know that they are working right.

fra77x wrote:What are you trying to achieve with these noise tests? We use noise to check the acoustics of rooms.
Why you don't just try a phase cancellation test?

Also you should use tools that you know that they are working right.

I used white noise (as was also suggested above) to check the spectral response of the devices.



I did a phase cancellation test and also posted the audio samples (see my audio files above) ... if you have any comments on these , please let me know ....
I also did a "Program material" spectral response comparison - 2 spctrographs on the right side of the posted jpg ...

My "Tool I know" is the one I used as reference ... I just had the ControlPak open on my SCope because I am checking it out and noticed this discrepancy ...

I haven't checked these.

I don't believe you can get any meaningful information about the frequency responce with these tests.

I hanen't used the devices you are trying to test so i can't comment on those.

By mine experience the information i gave you in the previous posts is more than enough.

Make an empty project with just the outputs so to be sure everything fits on a dsp.

Try minimal setups until you get repetitive reliable results.

If you hear phase problems then there are phase problems and you have to look for procedures how to avoid these.

The noise generator of the modular is a decent one.

Use wavelab which is guaranteed to work right.

I dont know what you set up in this pic (are you phasing the white noise with itself ??)

I dont have these devices/modules in scope pci ...


I am working on wavelab spectral analyses to upload (you can see slight differences but my screencapture is not working with it ...)


In any case - and most importantly - beyond the debates of ways to test spectral response and phase cancellations (i know a bit about waves and DSP) - please LISTEN to the examples I uploaded (through capable monitors/headphones) and tell me what you hear/think ...

Thanx

some tests.....

it all looks pretty normal.

Interesting Gary ... Not sure what to make of the THD curve (and why its only in the lows) - but it does seem like there are phase nonlinearities in the low end and a few spectral notches in that are to match (i am guessing that these could be more pronounced if there is a concentration of alot of lowend energy in a small band which has some of these nonlinearities (such as a tuned kick and single note bass) resulting in some cancellations (destructive interference) between neighboring bands that have been phase shifted (especially if - like in my case - all tracks (and thus lowend energy) is in phase originally ....) which could explain why i am noticing it more when phase compensation is turned on ....

One thing i didnt see is evidence of some sort of mid resonance (in wavelab i did notice some boost in the 200Hz area ... Will upload the pics soon ...)

Did you get a chance to listen to the audio i sent ?


Which compressors do you use on your masterbus ?

no processor, ESPECIALLY a hardware one, is ever going to be 100% transparent. there's no reason to expect software to be any different, nor is that needed.

yes, i didn't hear any problem in your samples, but it's possible that i'm not listening to what you want me to listen to.

compression on the masterbus? optimaster, and various master limiters.

depending on the source material, it's very possible that you might see a boost in certain frequencies, with any compressor. a compressor works by making to loud sounds quieter and the quiet sounds louder....

Im not expecting it to be transparent - i forgot to mention that one of the reasons for these compressors on the masterbus is to add a but of color and vibe as well ...

Second thing i forgot to mention above - not sure what 2A 1.8 threshold means in terms of compression on your signal or the thresholds on the other comps - but my examples are with minimum compression (max or min threshold/compression) - so i dont think its about the actual spectral changes due to the compression (and attack/release)

Thirdly - i also use multiband sometimes - but that is not the same as a glue compressor a-la ssl bus comp (or cytomic for example) which is what i am looking for in this case (and imho preferable than achieving the same peak/rms gain reduction with limiting ...)

I will post the spectrographs to help direct the listening - but again - sound like low and high end reduction/over-tightning (could be phase cancellation notches in the lows and resulting high artifacts) plus what seems to be a small boost around 200hz).
The bigger picture is that to my perception - the soundscape is "narrowed" from high and lows towards the mid - and sounds less "rich" ....


(Flick between the first and third (2A) where these differences are more pronounced ...)

Not very easy to notice - but there is a bit of attenuation around 50Hz and boosts around 200 and 500 in sections 3 and 4 (out of 5) especially ...

Which correlates to (- or subjectively influenced by) what I hear ....
Of course this doesnt fully represent changes in MId vs. Side etc ...

well, assuming what you hear is what is happening, you must decide if this helps or hinders the music you are doing. i don't think there's anything wrong or needing a fix, though.