So why not get a new model? Surely new technology is better?

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So why not get a new model? Surely new technology is better?

Post by Boeing 737-400 » Tue Feb 17, 2004 10:07 pm

I need someone who knows his synths here. To explain why I bought a Pro-One instead of one of these new hi tech digital synths. Basically I need you to explain why analogue can be better than digital.

Thank you.

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Post by monads » Wed Feb 18, 2004 2:36 am

I'll give it a shot. I would say basically because the oscillators, filters, envelops (etc.) are analog as opposed to being generated digitally through algorithms/microprocessors. Although these algorithms are modeled after some analog synths, they just don't sound the same. This is what it means for me and the reason why i would pick up vintage gear or a Voyager for that matter.

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Post by MC » Wed Feb 18, 2004 2:28 pm

There are oscillators.

An analog oscillator (VCO) originates its signal from a charged cap core; a cap is charged until it reaches a threshold and is reset, and the process repeats. This repetitive process gives us our basic ramp waveform from which other waveforms can be derived. The rate at which the cap charges (thus the VCO frequency) is controlled by the control voltage and is continuously variable.

Digital synths either replace the charged cap ramp generator of the oscillator with a digital waveform generator or the waveforms are generated digitally via a DAC. They're no longer VCOs because they are not controlled directly by an analog control voltage.

There is however a difference in the sound. Multiple VCOs are always running freely out of phase and independent of each other. There is always a little error present in the charged cap core, and the error is different in each oscillator. The phase is never the same between VCOs. Thus every time you trigger a set of two or three VCOs all tuned to the same intervals, the phase and intervals won't be perfect and they won't be consistent. So between the phase independence and the tiny circuit errors, each note never sounds exactly the same.

Contrast that with multiple digital oscillators whose phase and intervals are tightly controlled by the cpu. Every note sounds exactly the same. The tuning is very stable and there is no circuit error/drift to worry about in a digital synth. But because the phasing is tightly controlled, digital oscillators in unison sound very irritating and not as full as multiple phase-independent VCOs.

When you modulate a VCO with a pitch wheel, LFO, the waveform is always consistent. When you modulate a digital oscillator, the CPU has to interrupt the current waveform and start another one at the new frequency, and the waveform is never consistent. The CPU in a digital synth isn't fast enough to emulate the VCO behavior, it has too many other things to do. That's why VCOs sound "smoother" when you modulate them. While VCOs are continuously variable, digital oscillator are not. There are always discrete steps in digital, therefore modulating the pitch of a digital oscillator is not as smooth as analog.

Your ears perceive the phasing differences, and that is why analog oscillators sound more "refreshing" to the ears.

Then there are the filters.

I have yet to hear a digital or modeled filter come close to a good analog filter. Digital filters rely on a mathematical model (transfer function) of a filter. The problem is the math models of the filters are not accurate.

Take the Moog transistor ladder filter which is a 24dB lowpass filter. There are many variations of 24dB lowpass filters out there. Open a DSP textbook and the models of a 24dB lowpass filter you find in there are the generic types but are not the Moog 24dB filter. Those are no good. Not only that, the generic types are not resonant. If you want to model a resonant filter, the math model derivation gets a lot more complicated. If you want to model a resonant filter being modulated in real time (like audio FM), now we're talking serious elbow grease.

Well, where do you find DSP models of Moog filters, Oberheim filters, ARP filters, VCS3 filters, an SSM2040 filter? Nowhere, they're not in print. No one has published a DSP model of any of the popular synth filters. Well that means DSP designers have to engage their brain and figure out a model from scratch, and that is extremely hard work. The math model of a resonant synth filter is a LOT MORE COMPLEX than a generic filter, and in the end the transfer function still isn't accurate.

Engineers have tried for AGES to reduce a Moog filter down to a mathematical formula, not even the engineers at Moog Music back in the 70s could do it. There are things going on in analog filters that defy mathematical analysis, especially with dynamic voltage control and circuit interaction affecting resonance and distortion.

Digital resonant filters are the achilles heel of digital synths. I have yet to hear a digital resonant filter that can approach the resonant qualities of a real analog filter.

That poor digital cpu. First it has to deal with emulating analog oscillators, now it has to emulate resonant filters. There are some things that are easier to do in digital and those that are easier to do in analog. Digital has its strength with stuff like FM Synthesis and Additive synthesis, but analog still rules with resonant filters.

Like the Titanic, just because something CAN be built doesn't mean that it SHOULD be.

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Post by Boeing 737-400 » Wed Feb 18, 2004 5:52 pm

That explains quite a bit. Unfortunately I have to explain this all to two people who don't understand this technical stuff...

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Post by monads » Wed Feb 18, 2004 6:08 pm

MC wrote:There are oscillators.
Contrast that with multiple digital oscillators whose phase and intervals are tightly controlled by the cpu. Every note sounds exactly the same. The tuning is very stable and there is no circuit error/drift to worry about in a digital synth. But because the phasing is tightly controlled, digital oscillators in unison sound very irritating and not as full as multiple phase-independent VCOs.
But on some digital synths the oscillators are free running. You can even change the phasing if you wanted too (i.e Virus C). Every note will not sound exactly the same on a DCO synth.

I don’t think you really can compare a true analog synth to a digital analog synth and say the former is superior. They both have their strengths and weaknesses. I'm glad we have both as an option for creative purposes. I'm not trying to start a war here or anything. Your post was excellent. I especially concur with regards to the filters. I just believe the two can co-exist :D

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digital vs. analog

Post by FIGS » Fri Feb 20, 2004 1:47 pm

MC gives some great insight, but I would like to point out my observations/beliefs without being too technical, hopefully relating the differences to some everyday things.

First, nobody can explain why you bought a ProOne instead of a digi-synth except for you. Realize, I would make the same decision and I will tell you why:

Anything digital is merely a numeric representation or approximation of a real thing (thus the term "virtual" -- a photocopy of a $20 bill is virtually the same as a real $20 bill until you try to spend it :-) ).

If you run a flight simulator on your computer, have you really flown an airplane?

Digital devices have rates of sampling. A sample is like a photograph of a waveform. The higher the sampling rate, the more photographs per second in the hopes of capturing "enough" information about a waveform to represent it accurately. In most cases, the higher the sampling rate, the better the resolution.

HERE'S THE KICKER: for every sample taken, there is a non-sample, too. If the sampling rate is 44.1 kHz (like the redbook CD), that means a picture is taken 44,100 times per second. That seems like a lot. However, there are also 44,100 non-samples in that same second!

This does not change with higher sampling rates. At 96kHz sampling rate, you still are getting as many non-samples as samples (96,000).

I like to explain this to people by saying: the digital device is off as often as it is on. Kinda like a strobe light, even at its highest speed, it is still flickering (use a flouescent tube as an example). At first glance, it looks like white light, but staring at the element itself, you can see it flicker. Incandecent bulbs do not exhibit this phenomenon.

Analog synthesizers have an INFINTE sampling rate. In fact, there is just one long sample that never stops, like a record groove. LP records are analog representations of recordings (like CDs). The grooves are "analogous" to the audio waveforms. The needle tracks the groove ALL THE TIME. Unlike the laser in a CD player that is really only looking at the waveforms HALF THE TIME.

Lastly, audio is a three-dimensional entity (just look at a record groove). Digital is two-dimensional -- on/off or 1/0.

However, I need to express further that each has its own place and this may help you explain to your friends who are still baffled by your decision.

Digital is great for one thing: MEMORY. Your ProOne will only be able to be one "preset" at a time. To get from one sound to another, you must dial it in. Digital synths have memory presets so you can rapidly go from one sound to another. Also, your ProOne is never going to sound like a piano, many digisynths can represent familiar sounds pretty accurately.

I own and use a combination of analogs, digitals and virtual analogs. Each has its place. In the studio I prefer to record to analog tape, of course editting on a computer is much simpler than on a reel-to-reel. So certainly the application must be taken into account.

Do you need umpteen-million presets or just one fat sound? Do you want to go from a piano, to an organ, to a bass line? What about polyphony?

Your answers to your friends are the answers to those questions. Some folks want to carry one board and have all their sounds in there. Some folks like having a different board for each sound. The tradeoffs are simply that -- tradeoffs.
Thom Fiegle
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Post by Boeing 737-400 » Sat Feb 21, 2004 2:44 am

Firstly, I do think I made the right choice with the ProOne, to go with my Voyager! Not particularly fussy about piano sounds, or going from one preset to the other pretty quickly, but I do need that phat analog sound...
If you run a flight simulator on your computer, have you really flown an airplane?
Can't particularly see what you mean by this. I've done both! :)
Analog synthesizers have an INFINTE sampling rate. In fact, there is just one long sample that never stops, like a record groove. LP records are analog representations of recordings (like CDs). The grooves are "analogous" to the audio waveforms. The needle tracks the groove ALL THE TIME. Unlike the laser in a CD player that is really only looking at the waveforms HALF THE TIME.
Indeed. The difference between a LP and a CD is that the latter does not pick up every imperfection, i.e. dust and fingerprints when played.

I will need polyphony eventually though.

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Post by Array » Sat Feb 21, 2004 9:21 am

MC wrote:
Then there are the filters.

Well, where do you find DSP models of Moog filters, Oberheim filters, ARP filters, VCS3 filters, an SSM2040 filter? Nowhere, they're not in print. No one has published a DSP model of any of the popular synth filters. Well that means DSP designers have to engage their brain and figure out a model from scratch, and that is extremely hard work. The math model of a resonant synth filter is a LOT MORE COMPLEX than a generic filter, and in the end the transfer function still isn't accurate.
I'm not sure I understand this statement....

What about all of the emulations out there which mimic (semi-succesfully) the tonal characteristics of these filters? Arturia Moog Modular V comes to mind....

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Post by MC » Sat Feb 21, 2004 1:48 pm

What about all of the emulations out there which mimic (semi-succesfully) the tonal characteristics of these filters? Arturia Moog Modular V comes to mind....
Auturia didn't get it either. The "squelchiness" of a real Moog 904A lowpass filter module set to high resonance isnt' there. And try modulating the Auturia filter with audio FM - not the same.

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Why you bought a Pro One

Post by Kevin Bowden » Sat Feb 21, 2004 10:39 pm

Boeing - I can't answer your question as it is a pretty silly thing to ask quite frankly.

I have absolutely no idea why you spent money on something that cannot possibly 'enhance' your dabblings with your Voyager.

Having read some of your other recent posts on this forum you would surely have been better off investing in a midi-capable polyphonic board (with on-board sequencer and arpeggiator) that could interface with the Voyager via midi and provide access to the facilities you seem to be keen on using (albeit 'outboard').

Even with the current Voyager midi implementation limitations my Korg Triton Pro X (eugh, modern and digital) and Voyager are cavorting together like a couple of teenagers (to the extent that I may need to throw a bucket of cold water over them if I ever need to separate them !!!).

I personally believe that you could of spent your money more wisely - however, you have a Pro One to look after now, AND it is your money.

I recall some time ago that you said you had got yourself a PC Sequencer package - are you not yet using this with the Voyager ? This would be a starting point on the road to doing the kind of things you aspire to.

If you still haven't hooked your PC up to your Voyager via midi then you have no way of uploading either software updates or new voice banks - you also won't be able to use my voice librarian when it is released (and you'll certainly regret that).

I'm not saying that my view of what your priorities should be should be followed but this is all just offered as good advice based upon what you are/have been saying.

KB

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Post by Boeing 737-400 » Sat Feb 21, 2004 11:31 pm

I was planning on using them separately, well, next to eachother, which I did indeed do on one of my latest videos. When I get my stand it'll be a lot easier to play both at the same time. I have been looking at a Jupiter 8 actually, and perhaps I'll go for one that has the midi retrofit, or the Alesis Andromeda.

My "PC Sequencer package" as I said, is really crap, its something I downloaded free when Tony R. had the idea of loading a midi file into it to learn songs, which worked quite well. I also downloaded the MidiOX which you recommended, but as I have no midi cable at the moment its practically useless. What is your "voice librarian" exactly?

Incidentally, the point of this thread was for someone to explain why analogues are better than digital in some cases, and hopefully Mr. LU himself would come and read this.

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Post by LondonUnited » Sun Feb 22, 2004 12:48 am

Boeing 737-400 wrote:hopefully Mr. LU himself would come and read this.
I have. It certainly explained to me what the answer to the question (which i initially posed to Boeing) was. All thanks for this understanding must go to "FIGS" for explaining it in laymans terms, and thus cutting out a lot of the jargon which i havn't got a grasp of at all.

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Digital vs. analog

Post by FIGS » Mon Feb 23, 2004 12:00 pm

Boeing 737-400,

I wrote:
If you run a flight simulator on your computer, have you really flown an airplane?
And you replied:
Can't particularly see what you mean by this. I've done both! :)
Then you should know exacty what I meant! The difference between a datastream and real experience is exactly that.

Then I compared CDs and LPs in hopes of making another example of this complex difference and you responded (just as wittingly),
Indeed. The difference between a LP and a CD is that the latter does not pick up every imperfection, i.e. dust and fingerprints when played.
Which makes me think you are not really interested in an answer at all :(
A CD is full of imperfections (read my earlier post again, it is really only half of the information!) A/B you favorite recording (as I have) on CD and on vinyl, you will hear the difference yourself. Which one you prefer is up to you, but first you must hear a difference to even have an opinion.

For all the other folks participating in this discussion, I think the most important aspect of the comparison is in the user's requirements of the device (and thus the technology used to accomplish it).

If the use of MIDI is required, then that eliminates (or obviates) a lot of options right away. Polyphony, save-and-recall, etc. -- same deal.

But if the quest is for the real thing, then there is really only one option: the real thing. The best piano sound comes from a piano. Of course an acoustic piano requires a different kind of maintenance. If you do not wish to tune and care for a piano (ie: if this is NOT your requirement), then a digital piano is a good substitute (I have both, I have A/B'ed them. There is no contest soundwise, but I have never had to tune my digital). Same as the CD/LP comparison -- yeah, only handle the LP by the edges, keep it clean, align your stylus regularly, do NOT take them to the beach!

I have a VA that has presets saying things like "Moog", I compare them to my Mini-D, again -- no contest. The same VA has presets for "OB", I compare them to my OB-8 -- no contest.

However, the convenience of a small, easy to transport, VA which has not only "adequate" simulations of the realthings but some options that the real things cannot do at all, allows the VA to win a completly different contest.

If sound is the thing, go for the real thing. But be prepared to "maintain" those real things (warm-up time, stabilities, etc.). If an easy load-in/load-out from the gig (especially in the Chicago winter!) is the thing, then consider something else.

In my studio, I use the real things. On the road, I use simulations (easier to transport, more "reliable" in rough and tumble conditions, and MOST important -- replaceable if damaged or stolen ).

Hope this helps,
Thom Fiegle
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Post by Boeing 737-400 » Tue Feb 24, 2004 2:45 am

Firstly, in reference to that whole flight sim thing, I flew an A320 in a full size simulator, but have not flown the real one so cannot comment. I have flown a real 737-300 for 20 minutes, but only ever flown a 737-400 in a PC simulation. There's comparable differences between the two, but the PC one does do a good simulation of the real counterpart, and allows me to do things I cannot do in the real thing.

And the whole CD thing. It can give a clearer sound, and the media lasts longer and is harder to damage than vinyl. However, if I have a very good condition vinyl, with no dust or scratches on it, and a good stylus and amplifier, the sound quality is a lot better. :D

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Post by StefanH » Tue Feb 24, 2004 5:06 am

Hi,
i wonder why u ask for the diffrent of a VA and the real analog Synthesizers?
I honestly thought, that you know what you want, that's why you bought the MMV and ProOne.
Didn't you ever played with an Virus, Q, MicroWaveXT or NordLead? Now i am 100% sure that all of these above will blow out you mind too.
They sound in a way more like a cd, cleaner, more brilliance, but sometimes (NL) cold! But i like them also, and together with some real analog Synths, i get a perfect mixture out of them. Analog Synth's sounding warmer, sometimes they got more dirt (FR-777).
Both Worlds growing together this times, see the evolver, a perfect mix between analog and digital technology.
I thought u know all of this befor you bought something.

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