INTERACT FORUM

Please login or register.

Login with username, password and session length
Advanced search  
Pages: [1]   Go Down

Author Topic: MC21 Spectrum "Analyzer" questions  (Read 4548 times)

Rizlaw

  • Regular Member
  • Galactic Citizen
  • ****
  • Posts: 283
MC21 Spectrum "Analyzer" questions
« on: November 09, 2015, 10:57:33 am »

I just purchased my upgrade Master MC21 License for Linux. I use Ubuntu 14.04 LTS. I've attached a screen shot of the DSP Studio "Analyzer" and have the following question(s):

1. Is there a screen rendering issue in MC21 for Linux or is the vertical axis of the graph missing the "db" range? I realize that the top left of the graph shows "Volume RMS" but the vertical axis should have "db" markings in my opinion.

2. Am I correct in assuming (always a dangerous thing to do) that the fill in boxes at the lower far left and far right of the "frequency" axis are supposed to denote the lowest and highest frequencies in the overall range. There is no clear explanation of this in the wiki, nor is there a pop up dialogue for the fill-in boxes.

3. Resizing the spectrum analyser window (widening it), does not seem to add additional frequency numbers (i.e. 10k, 15k, etc.) along the bottom axis (I do realize each vertical line represents a 1k increment, from 1k on up, but I also expect to see more printed numbers than presently shown.

Logged
Ubuntu Gnome 20.04 LTS

mwillems

  • MC Beta Team
  • Citizen of the Universe
  • *****
  • Posts: 5233
  • "Linux Merit Badge" Recipient
Re: MC21 Spectrum "Analyzer" questions
« Reply #1 on: November 09, 2015, 11:08:24 am »

I just purchased my upgrade Master MC21 License for Linux. I use Ubuntu 14.04 LTS. I've attached a screen shot of the DSP Studio "Analyzer" and have the following question(s):

1. Is there a screen rendering issue in MC21 for Linux or is the vertical axis of the graph missing the "db" range? I realize that the top left of the graph shows "Volume RMS" but the vertical axis should have "db" markings in my opinion.

The windows version also lacks a dB scale, it would be nice to have but does not currently exist. (i.e. it's not a screen rendering issue, it's just not implemented).

Quote
2. Am I correct in assuming (always a dangerous thing to do) that the fill in boxes at the lower far left and far right of the "frequency" axis are supposed to denote the lowest and highest frequencies in the overall range. There is no clear explanation of this in the wiki, nor is there a pop up dialogue for the fill-in boxes.

They do represent the bottom and top of the displayed frequency rang; your assumption is correct.

Quote
3. Resizing the spectrum analyser window (widening it), does not seem to add additional frequency numbers (i.e. 10k, 15k, etc.) along the bottom axis (I do realize each vertical line represents a 1k increment, but I also expect to see more printed numbers than presently shown.

The vertical line does not represent a 1K increment on most parts of the graph.  The graph is standard logarithmic representation of frequency response i.e. the line spacing is identical to most professional spectral graphs and is intended to give each octave equal horizontal space on the graph (because we perceive tone separation logarithmically).  So for each "decade" the vertical lines represent one tenth of the decade, which is why they get closer together as they move up the decade.  So the lines only indicate 1K of separation between 1K and 10K; between 10k and 100k the lines indicate 10K of separation, between 100Hz and 1k each line is 100Hz, etc.  On most conventional FR graphs you might only see the decades marked, and it's extremely uncommon to see intermediate markings between 10k and 20k (as it's just one octave). So I feel lucky we have as many markings as we do here  ;D

Of note: the analyzer is not particularly accurate at extremes (either low or high frequency) for whatever reason.  I wouldn't suggest using it as anything other than a quick and dirty check to see if something's on and loosely what it's doing.  It's not a reliable witness for precision work.
Logged

Rizlaw

  • Regular Member
  • Galactic Citizen
  • ****
  • Posts: 283
Re: MC21 Spectrum "Analyzer" questions
« Reply #2 on: November 09, 2015, 11:15:47 am »

Thanks for the explanations. Is there a more accurate spectrum analyser for Linux that can be installed (free or paid)?
Logged
Ubuntu Gnome 20.04 LTS

mwillems

  • MC Beta Team
  • Citizen of the Universe
  • *****
  • Posts: 5233
  • "Linux Merit Badge" Recipient
Re: MC21 Spectrum "Analyzer" questions
« Reply #3 on: November 09, 2015, 11:20:18 am »

Thanks for the explanations. Is there a more accurate spectrum analyser for Linux that can be installed (free or paid)?

I can't recommend one as I generally don't use spectrum analyzers for DSP work: for precision work, I take measurements with a microphone. For a quick visualization, JRiver's analyzer has been "good enough" for me.  

The popular measurement suite Room EQ Wizard is available at no cost, and does run on linux (although not quite natively).  I've used it with good results in the past on linux systems to take measurements and as a real time analyzer.  

Other users may be able to recommend some linux-compatible analyzer plugins though.
Logged
Pages: [1]   Go Up