Seven Phases Spectrum Analyzer

VST, AU, etc. plug-in Virtual Effects discussion
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KVRist

Topic Starter

347 posts since 20 Apr, 2005 from Moscow, Russian Federation

Post Tue Jul 28, 2015 7:36 am

mystran wrote: For most musical signals with harmonic overtones, the difference varies smooth between these two extremes with low harmonics (assuming sufficient resolution) measuring individually with the same slope in either case and high harmonics measuring with a 3dB difference.
Mmm... Yes, your're right. I guess I somewhat oversimplified my explanation above (by thinking of noise-like signals too much). Indeed, if we also take individual harmonics, trivial 0dB <-> 3dB tilt conversion between two models does not work.

KVRist
40 posts since 17 Oct, 2020

Post Tue Jun 22, 2021 8:22 am

I really, really love this analyzer, for reasons stated in this gentleman's post
i couldn't have said it better. precision is one thing, but i mostly use analysers in a more contextual way - i use it to crosscheck with mixes that are sounding exellent, to a/b my production with the exellent one that's already there. and with the seven phases analyser i finally saw what i heard. i f.e. like most of the voxengo stuff, there's no doubt that it is highes possible quality, but i just can't get used to "read" span, even with all the customising possibilities. with the seven phases analyser i can. the eye to ear connection is there.
It used to help me a lot with mixing, the problem is this plugin doesn't work on MacOS which I'm using recently. Is there anything like this plugin available on Mac?

KVRAF
2482 posts since 13 Mar, 2004

Post Tue Jun 22, 2021 9:19 am

Azbest wrote:
Tue Jun 22, 2021 8:22 am
I really, really love this analyzer, for reasons stated in this gentleman's post
i couldn't have said it better. precision is one thing, but i mostly use analysers in a more contextual way - i use it to crosscheck with mixes that are sounding exellent, to a/b my production with the exellent one that's already there. and with the seven phases analyser i finally saw what i heard. i f.e. like most of the voxengo stuff, there's no doubt that it is highes possible quality, but i just can't get used to "read" span, even with all the customising possibilities. with the seven phases analyser i can. the eye to ear connection is there.
It used to help me a lot with mixing, the problem is this plugin doesn't work on MacOS which I'm using recently. Is there anything like this plugin available on Mac?
Not sure what aspect(s) of the Seven Phases analyzer that post is exactly referring to, but if it's about the fact that it uses a filter bank (as opposed to FFT), the HOFA Analyzer does this too according to its description.

KVRAF
4125 posts since 17 Dec, 2009

Post Wed Jun 23, 2021 3:18 am

wonder if Voxengo AnSpec is also a filter bank or just a limited FFT.
Image

KVRAF
2482 posts since 13 Mar, 2004

Post Wed Jun 23, 2021 5:11 am

Ploki wrote:
Wed Jun 23, 2021 3:18 am
wonder if Voxengo AnSpec is also a filter bank or just a limited FFT.
Wasn't aware of that one.
Just tested running pink noise through and it shows (more or less) flat, so according to what was discussed here looks like it's using a filter bank indeed (or has 3 dB slope built in if FFT based, but I'd rather doubt that if not mentioned explicitly).

KVRist
40 posts since 17 Oct, 2020

Post Wed Jun 23, 2021 7:59 am

No_Use wrote:
Tue Jun 22, 2021 9:19 am
Azbest wrote:
Tue Jun 22, 2021 8:22 am
I really, really love this analyzer, for reasons stated in this gentleman's post
i couldn't have said it better. precision is one thing, but i mostly use analysers in a more contextual way - i use it to crosscheck with mixes that are sounding exellent, to a/b my production with the exellent one that's already there. and with the seven phases analyser i finally saw what i heard. i f.e. like most of the voxengo stuff, there's no doubt that it is highes possible quality, but i just can't get used to "read" span, even with all the customising possibilities. with the seven phases analyser i can. the eye to ear connection is there.
It used to help me a lot with mixing, the problem is this plugin doesn't work on MacOS which I'm using recently. Is there anything like this plugin available on Mac?
Not sure what aspect(s) of the Seven Phases analyzer that post is exactly referring to, but if it's about the fact that it uses a filter bank (as opposed to FFT), the HOFA Analyzer does this too according to its description.
I don't even know what filter bank / FFT means. The reason I like Seven Phases so much is the responsiveness and precision of frequency "bars", for the lack of a better description.

AnSpec is nowhere near as good. I'll try Inspector XL Analyzer by RNDigital, maybe it will do the trick.

KVRAF
6398 posts since 12 Feb, 2006 from Helsinki, Finland

Post Wed Jun 23, 2021 8:21 am

No_Use wrote:
Wed Jun 23, 2021 5:11 am
Ploki wrote:
Wed Jun 23, 2021 3:18 am
wonder if Voxengo AnSpec is also a filter bank or just a limited FFT.
Wasn't aware of that one.
Just tested running pink noise through and it shows (more or less) flat, so according to what was discussed here looks like it's using a filter bank indeed (or has 3 dB slope built in if FFT based, but I'd rather doubt that if not mentioned explicitly).
As I pointed out in the post right below the one you linked to, you can also do the test with a slow constant-amplitude sine sweep (no need to be that scientific really, just sweep a sine oscillator). If both pink noise and a sine-sweep measure flat, then you've got a log filter-bank or something that is doing a good job trying to pretend to be one.

I just tried Voxengo AnSpec (quickly anyway) and it measures flat for sines and flat for pink noise, so it looks like a pretty standard log filter bank.
Preferred pronouns would be "it/it" because according to this country, I'm a piece of human trash.

KVRAF
2482 posts since 13 Mar, 2004

Post Wed Jun 23, 2021 2:52 pm

Azbest wrote:
Wed Jun 23, 2021 7:59 am
I don't even know what filter bank / FFT means. The reason I like Seven Phases so much is the responsiveness and precision of frequency "bars", for the lack of a better description.
I'm not that much of a DSP guy but I think that's a point where filter bank based analyzers may have an advantage indeed.
To quote from a thread in the REAPER forum:
For example, usually FFT spectrum analyzers have a trade-off between frequency and time resolution. Ideally, for music you'd use FFT setting of 16384, to have reasonable frequency resolution in bass. But at that setting time will not be represented in the analyzer as a human hears it - what is shown will have latency and smearing in time dimension.
With filter bank based analyzers there isn't this trade-off I think (someone correct me if wrong).

KVRAF
6398 posts since 12 Feb, 2006 from Helsinki, Finland

Post Wed Jun 23, 2021 3:12 pm

No_Use wrote:
Wed Jun 23, 2021 2:52 pm
For example, usually FFT spectrum analyzers have a trade-off between frequency and time resolution. Ideally, for music you'd use FFT setting of 16384, to have reasonable frequency resolution in bass. But at that setting time will not be represented in the analyzer as a human hears it - what is shown will have latency and smearing in time dimension.
With filter bank based analyzers there isn't this trade-off I think (someone correct me if wrong).
It's a tiny bit more complicated. The time-frequency trade-off is fundamental. It's an instance of the uncertainty principle.

However, there is no reason why this trade-off would have to be the same everywhere. With FFT all the bands have the same (linear) bandwidth, so the time-resolution of all the bands is also the same, but with a log-frequency (ie. "per octave") filter bank the (linear) bandwidth becomes wider at higher frequencies (it doubles for each octave), so the time-resolution can become better (ie. twice as responsive for each octave).

In practice, with a typical log-frequency filter bank the higher bands actually quickly become "too" responsive in terms of time resolution and your average analyzer will usually do some additional smoothing over time so the graphics aren't quite as jittery, but the basic idea is that you can have good frequency resolution at low frequencies, but also good time resolution at higher frequencies where you don't need quite so much frequency resolution.
Preferred pronouns would be "it/it" because according to this country, I'm a piece of human trash.

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