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JPC, DD, at it again w/LTD02 stirring the pot...


Bossobass Dave

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I've always contended, when in the past I attempted to engage J in a more serious manner, that the higher frequency rez settings were not smeared at all. The limitations came from the lack of color separation per Hz (color density) and the scroll speeds.

 

My reasons for changing settings were that the higher time rez settings smeared, or obscured the frequency content resembling a stack of colored boxes.

 

J has recently commented on an earlier post of mine, saying that my preferred settings are a smeared mess and that the pixelated 3 Hz frequency rez setting is his preferred option.

 

Using the settings I've been using for a number of years, I only changed the color scale to illustrate what I've said in the past. The color scale I use is closest to that used by the earliest posters of SL caps from years ago. I chose to use it strictly to honor the pioneer's choice of color scale and so that there would not be a radical departure, sparing the confusion that would cause.

 

First, a look at the current settings with the age-old color scale and with a color scale that doubles the color/Hz density. This is the plane crash scene from WOTW, zoomed:

 

3eaeb4117ad7aff18408b42a2eee5f14.gif

 

You can (hopefully) see the smeared, or airbrushed effect from lack of colors fade into a much better defined graph, showing the high frequency rez.

 

Here's a full shot of the Go-To-Warp scene from Star Trek, comparing the settings J likes to the settings I use with the higher density color scale:

 

9636872c0fd2a70061bf1cba9c3011a6.gif

b958ccacec764985f0286d18eba01ce3.png

8822dc139953244bd3a0860c5dc39df2.png

 

These graphs have helped me immensely in designing and building subwoofers that are meant to accurately reproduce modern movie soundtracks and multi-channel hi-rez music. The setting I use with the high density color scale show immeasurably more detail in that regard. What anyone else sees in them or thinks they portray or prefers them to portray is a big, fat irrelevant to me.

 

No one has posted anything that changes my position on this tool as the best one for assessing the content and the requirement to replay that content. The stack-of-4-colors-of-pixel-boxes settings I used in the beginning are OK, but not even close to the analysis the "smeared mess" settings give me.

 

YMMV, IMHO, WCWYT, etc.

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So we went from the graphs being down 3db per octave to now back to the original beef, "your settings are wrong". Great. Wtf is up with JPC? He hardly ever posts except for when something you say or do comes up. I'm starting to think he hates you and your air purifier looking pos subs. :lol:

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Hahahaha I was gonna say something along that line but didn't wanna offend anyone. It is weird though cuz it's like an obsession. As soon as he saw that thread he jumped all over that. 

 

No one here is gonna change their minds about how we graph and no one at AVS cares except JPC so he needs to let it go. Well unless he does start his own thread. :P

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He is a clown beyond reason.  I used to argue with that guy about Keith Yates' "Way Down Deep" article series.  He misunderstood and misinterpreted everything, and stood by his position as if gospel.  I knew then that further argument would simply waste time, like trying to convince a true believer of anything beyond/beside what they have been taught, in spite of, no...in the teeth of evidence to the contrary.  He belongs at the new AVS.

 

JSS

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I agree with all comments regarding "ignore".

 

I just wanted to clear the air about what we've done here over the past few years so that people don't think it was all for nothing and that, as LTD put it, "the huge body" of SL caps and peak hold data aren't a gross misrepresentation of the content.

 

I've run SL caps with the mic on the floor so it doesn't take up my main seat when I watch a good MWB and also run a REW FR measurement with the mic at the same place and then run a looped version and compared all 3... many times. I did them much more carefully for this thread and marked the graphs to show the direct comparisons in (+/-) dB.

 

We also then measured voltage out of the sub amplifier, critically measured excursion of the drivers and matched that data as well to the results mentioned above.

 

They are very close. Certainly not 20dB exaggerated and no peak hold traces had to be tilted and no 3dB/octave filter was necessary.

 

I'm not gonna post that stuff as I think most people who are interested in the content forums get it and the horse has been beaten to a puree.

 

Paul is taking a lot of heat at AVS from Bosso-Haters and OPPO fanbois. :D:lol::blink:

 

Baptism of fire. Welcome to the club and get over it. ;)

 

Some people will say that what I'm about to say is just because he's my son and those folks (especially Lisa Minelli, who is easily as annoying as JPC, IMO... yeah, if you ever met Stereodude, you'd get the joke right off) should be rushed to an MRI to be checked for brain damage. But, it's just stating the facts... Paul has state of the art hardware and software and is as meticulous as any engineer when it comes to use of the equipment to measure what's what. Any road block I've ever run into about low freqs, and there have been many, bouncing it off Paul has always cut a quicker path to the answer. People who flap their jaws and produce nothing are irrelevant. Accomplishment is everything, opinions are worth the price paid to post them.

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my interest all along has been from the observation that spectrum lab isn't presenting what folks think they are seeing--the amplitude of the signal at each frequency isn't what is presented in spectrum lab (except in the case of pure sine waves). 

the fft is calculating average energy across the measurement window and displaying that as the "level".  as a result, the "level" will display higher for low frequencies than for high frequencies even when the actual level of the signal itself is the same simply because a cycle of a low frequency fills a greater portion of the time window than does a high frequency.  it starts out as zero-difference for sine waves, gets problematic with transient responses where the length of the signal is significantly less than the length of the measurement window, and it completely breaks down for impulse-like responses.

 

most content is not characterized by sine waves, so the more accurate method of presenting the level of each frequency is to use some sort of adjustment.  the log adjustment (3db/oct) of the rta seems as reasonable to me as anything, but by the nature of the fft there just isn't any way to present what we all would like to see--the level that each frequency is recorded on the disc. 

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FFTs, like every other metric or scale, have their drawbacks, and we discussed this at length in the beginning of the LF content thread. Given that psychoacoustic research points to an 'integration time' in hearing, almost like the 'frame rate' of our vision, I think FFT is valid for measurement of material. You are more than welcome to create and post up 'corrected' versions of every PvA and scenecap on the LF content thread, based on you interpretation of what should be 'correct'.

 

JSS

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You can not rationalize with the irrational.  I know people that just make shit up and argue their made up facts to death!  All I know is that when my room shutters the spec graph shows a blob at low frequencies and I don't care if it is off by 3 dB or whatever.  The fact is the deeper and louder my system has become the better the movie experience.  I love the people that say under 20hz makes bass sound boomy and then say you can't hear under 20hz in the next paragraph, WTF to that! 

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FFTs, like every other metric or scale, have their drawbacks, and we discussed this at length in the beginning of the LF content thread. Given that psychoacoustic research points to an 'integration time' in hearing, almost like the 'frame rate' of our vision, I think FFT is valid for measurement of material. You are more than welcome to create and post up 'corrected' versions of every PvA and scenecap on the LF content thread, based on you interpretation of what should be 'correct'.

 

JSS

 

 

I agree with this, a very good summation and suggestion.

 

There are many settings available to average and or smooth the FFT in the SL options. LTD, Mo and J have looked at a few of them and issued a somewhat scatterbrained decree, IMO.

 

Sine waves are not the only input signal that shows correct energy levels in the content. Again, that statement suggests that all soundtrack content, short of a single sine wave effect, are misinterpreted by SL measurements.

 

Not true.

 

We're talking about a relatively very small bandwidth of frequencies. The content in soundtracks within that bandwidth are correctly displayed 99% of the time to a high degree of accuracy. The SL data is verifiable by measurement of the signal to the subwoofer system and the subwoofer system's reaction to that signal, as James notes above.

 

Those of us who have multi-channel audio as a hobby have always been interested in a new metric that shows better detail which leads to better performance. Bring it on and we'll embrace it.

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Besides the obvious... LOL to the MWB JPC picks and double LOL to "the JPC method" of settings (what next? :rolleyes: )... here is a simple exercise for anyone to try (except that LTD can't because he has no subwoofer and JPC can't because he has no subwoofer that can replay 10 Hz)

 

8545ce5d01b123d584b540f83bd11092.gif

 

With the playback levels properly adjusted for the experiment, a pair of 15s calibrated flat at the seats to <10 Hz will have approximately 25 mm of one-way throw to reproduce the 10 Hz part of this scene with the "anti-house curve" version or whatever the hell it's supposed to be. With the normal graph, the excursion would be 45 mm.

 

Those of us who have systems that are capable of flat playback to single digits already know what the outcome will be as there is no mistaking the difference in excursion between the 2 graphs. 45 mm will destroy most 15s, so we have to add 15s until there is no destruction and add more 15s again until there is headroom to run hot with clean replay.

 

Of course, the scene selected is one of J's typical Bridges Of Madison County Movies With NO Bass (I think he calls it less bombastic ;) ) and has nothing whatever to do with the subject at hand, so please use a 5 star MWB. The list can easily be found in the Content forum and post a question in any thread there if you need help finding an appropriate scene. :rolleyes:

 

It probably won't consist of drum strikes or a single hit at 10 Hz at -30dBFS. :rolleyes:

 

And, you might want to adjust your SL settings so that you can actually see what the hell is going on <100 Hz. :rolleyes:

 

And, please make a video and post it because we all love to watch drivers explode. Slo-Mo will be great. :)

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FYI, just posted some caps in the Jupiter Ascending thread. Subs are running quite hot, interface is adjusted below clipping and offset is adjusted so that both adjustments show no frequency greater than 0dBFS, even though, in reality, the system is definitely doing so.

 

I did one for JPC so he wouldn't feel left out, since he lurks here every 12 seconds or so. :lol:

 

88c3901f770971eb4e13069ddaa0f75c.gif

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Besides the obvious... LOL to the MWB JPC picks and double LOL to "the JPC method" of settings (what next? :rolleyes: )... here is a simple exercise for anyone to try (except that LTD can't because he has no subwoofer and JPC can't because he has no subwoofer that can replay 10 Hz)

 

8545ce5d01b123d584b540f83bd11092.gif

 

With the playback levels properly adjusted for the experiment, a pair of 15s calibrated flat at the seats to <10 Hz will have approximately 25 mm of one-way throw to reproduce the 10 Hz part of this scene with the "anti-house curve" version or whatever the hell it's supposed to be. With the normal graph, the excursion would be 45 mm.

 

Those of us who have systems that are capable of flat playback to single digits already know what the outcome will be as there is no mistaking the difference in excursion between the 2 graphs. 45 mm will destroy most 15s, so we have to add 15s until there is no destruction and add more 15s again until there is headroom to run hot with clean replay.

 

Of course, the scene selected is one of J's typical Bridges Of Madison County Movies With NO Bass (I think he calls it less bombastic ;) ) and has nothing whatever to do with the subject at hand, so please use a 5 star MWB. The list can easily be found in the Content forum and post a question in any thread there if you need help finding an appropriate scene. :rolleyes:

 

It probably won't consist of drum strikes or a single hit at 10 Hz at -30dBFS. :rolleyes:

 

And, you might want to adjust your SL settings so that you can actually see what the hell is going on <100 Hz. :rolleyes:

 

And, please make a video and post it because we all love to watch drivers explode. Slo-Mo will be great. :)

What?! Are you serious? No ULF capable playback system or experience with one. I'd make damn sure that I had a reference capable ULF system for real world testing of my theories. They just lost credibility with me. Winisd is a great tool but I'd never take that over Josh's real-world testing here.

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This is not the only effect with a big hit @ 25.'x' Hz. There are several in the movie, but this was the biggest transient effect.

 

Regardless of what reality one resides in, there is a LOT of bass in this scene that's centered at 25 Hz and is much hotter from 15-40 Hz than anywhere else in the soundtrack with it's peak at 25.'x' Hz. The spectrograph coordinates nicely with the amplitude bar's waveform which coordinates nicely with Nube's peak hold trace, regardless of your religious beliefs. ;)

 

WRUSlnK.png

 

 

Quoted from the JA thread for the Flat-Earthers who hang out here. This one ^^^ is public domain. Please use it and attach your comments for comic relief. :wub:

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