You are probably already using Zero Delay Feedback filters, so let your customers know!

[Full Bucket]

Thanks mdsp, superb listing!

F. Fontana. Computation of linear filter networks containing delay-free loops, with an application to the waveguide mesh. IEEE Trans. on Speech and Audio Processing, 11(6):774-782, Nov. 2003.

Also see here:
http://www.kvraudio.com/forum/viewtopic ... 01#4256701

Cheers, Björn

[andy-cytomic]

Please show me a particular place where I pretended to have invented the prior art. ...

As for your claim that you never argued about the TPT method, I think you're trying to be too smart here. The only thing I ever claimed to invent is the TPT method, which currently is being referred to by others as the ZDF.

Vadim, your TPT method is what I'm talking about, you claim it is new. It is just different notation applied to standard circuit modelling methods, it offers nothing new, apart from introducing new acronyms and alternative notation:

https://cytomic.com/files/dsp/OnePoleLinearLowPass.pdf

[andy-cytomic]

hi

I've been following all these discussions for some time, and I'm no expert and don't pretend to understand all the details and subtleties of each approach, so I prefered to stay silent until now.

But what I've missed most when reading about andy's or vadim's work (and thanks both for taking the time to publish) was the few comparisons of their methods against the state of the art.

Hi msdp, thanks for posting all those useful links! I understand it is tempting to call it "andy's method", but I am always at pains to point out that this stuff has been around for a long time, I didn't invent it, and I always provide references for people to read so they can see how this fits into a broader framework, so please read the references! All I have done is provide some worked examples and numerical optimisations.

[FastTriggerFish]

So what was the point of this thread exactly appart from pure trollbaiting ?
Andy: I don't know you other than reading your posts here and on JUCE forum but it's not the first time I see you come accross as a bit of a knob, maybe you should reevalulate how you behave on public forums regardless on how right you think you are.
Personally it puts me off your products as well as your ideas and insight which is a shame as I think both are great.

[pinkpanther]

In this thread Andy invented zero delay feedback filter trolling. Now that's unique!

Next Cytomic The Drop update will have it. Your music will start speaking senseless speech and way over the line phrases. Perfect for your next top hit remix.

[xoxos]

I thought it might be useful for people to know that for anyone using RBJ audio eq cookbook code (or any other bilinear z transform method) these are in fact Zero Delay Feedback filters! That's right, anything that uses trapezoidal integration, which is an implicit integration method, solves for things without any delays in feedbacks

So now you can all in good conscience, and with complete honesty, add the wonderfully enticing bullet point to your feature list:

• Featuring Zero Delay Feedback technology!

it's possible that i missed some subtlety in the discussion, it's also possible someone wanted me to think i was missing some subtlety in the discussion by dragging it into the depths of exclusory vernacular. doesn't matter what i say really.

what cytomic has stated here is a very natural reaction to the overboard commercial hyping of 0dff from ooh.. 2008 to 2011 or thereabouts, wherein numerous threads were posted with vehement and windy "eclectic consumers" stating how they wouldn't dare pay attention to any release without 0dff, inciting sedulous page upon page of "debate".

at the time, many developers were clueless as to how to participate in this new trend. some technical term is kicked up, then everyone is wondering "how can i too offer anechoic chamber technology?"

it was all very priggish and punishing for developers to be written off by these "consumers" because they were using "yesterday's filter technology", and of course highly profitable for those who were in. "successful marketing campaign" aka "making a killing".

most of the sourced 0dff i've tried do sound nice, i'm glad for them, but dang, the attitude of elitism, even if expressed only in the demands of these "eclectic consumers" (pending they were actual consumers at all) was real tiresome.

now pretty much what i'm seeing is a bunch of guys saying andy is a bitch, and i'm tired of that. what i actually see is dogpiling, mass accusations (and i know about how that works), more than any offense. why is it such a big deal to all the folks piling on andy.

are they in some secret vigilant club, appearing out of nowhere to protect our innocent eyes?

make a list, folks.

[matt42]

As far as I can tell Andy's position has nothing at all to do with the perceived elitism of TPT filter design.

What I find ironic in what you have to say xoxos is that it is Vadim, or Z1202, who has probably done the most out of anyone to bring this technology to the masses (at least his paper seems to be very well know and often quoted in Audio DSP discussions). Vadim, the same guy who is being harassed here by Andy, who you defend, whilst you bleat on about the "exclusory" nature of TPT filters.

are they in some secret vigilant club, appearing out of nowhere to protect our innocent eyes?

Seek help, immediately.

[ChiTown24]

I thought it might be useful for people to know that for anyone using RBJ audio eq cookbook code (or any other bilinear z transform method) these are in fact Zero Delay Feedback filters! That's right, anything that uses trapezoidal integration, which is an implicit integration method, solves for things without any delays in feedbacks

So now you can all in good conscience, and with complete honesty, add the wonderfully enticing bullet point to your feature list:

• Featuring Zero Delay Feedback technology!

it's possible that i missed some subtlety in the discussion, it's also possible someone wanted me to think i was missing some subtlety in the discussion by dragging it into the depths of exclusory vernacular. doesn't matter what i say really.

what cytomic has stated here is a very natural reaction to the overboard commercial hyping of 0dff from ooh.. 2008 to 2011 or thereabouts, wherein numerous threads were posted with vehement and windy "eclectic consumers" stating how they wouldn't dare pay attention to any release without 0dff, inciting sedulous page upon page of "debate".

at the time, many developers were clueless as to how to participate in this new trend. some technical term is kicked up, then everyone is wondering "how can i too offer anechoic chamber technology?"

it was all very priggish and punishing for developers to be written off by these "consumers" because they were using "yesterday's filter technology", and of course highly profitable for those who were in. "successful marketing campaign" aka "making a killing".

most of the sourced 0dff i've tried do sound nice, i'm glad for them, but dang, the attitude of elitism, even if expressed only in the demands of these "eclectic consumers" (pending they were actual consumers at all) was real tiresome.

now pretty much what i'm seeing is a bunch of guys saying andy is a bitch, and i'm tired of that. what i actually see is dogpiling, mass accusations (and i know about how that works), more than any offense. why is it such a big deal to all the folks piling on andy.

are they in some secret vigilant club, appearing out of nowhere to protect our innocent eyes?

make a list, folks.

ya, it's evident that it's the marketing aspect he's taking issue with. What I don't get his why he doesn't campaign against those devs who milked it for marketing purposes. That wasn't Vadim, or even NI - who Vadim works for or is associated with. Monark is their first commercial, marketed standalone instrument to implement the method and IMO they're only reference in the marketing blurb to the 0dfb/TPT filters is minimal - and it doesn't fall into the 2008 - 2011 window you provide. You certainly don't see the NI CEO picking arguments with other devs on the forum or making sly remarks, arguing about who's "really" got the best most genuine 0dfb filter, who got it first etc, or a legion of dutiful fanboys that he chats with regularly doing the same in his stead without discouragement. So, you know, I agree with both you and Andy with respect it's a shitty marketing stick with which to beat others, but I just don't agree that it's Vadim/NI who deserve the agro on that basis. I'd respect Andy's position more if his rhetoric was aimed at the right people. Though, as far as I can see and unless I'm mistaken, he may have actually collaborated with or at least assisted the worst offender of this aggressive 0dfb marketing stuff. http://www.cytomic.com/about

[Urs]

Well, I for one feel crucified by people who have neither seen our code nor our method.

I don't believe it was our marketing campaign that started the hype about zero delay feedback filters with users, it was Diva's sound. Which even after two years is testament to our approach - where a unit delay in the feedback path is the only difference in the lowest quality mode, albeit an audible one. QED.

[andy-cytomic]

As far as I can tell Andy's position has nothing at all to do with the perceived elitism of TPT filter design.

What I find ironic in what you have to say xoxos is that it is Vadim, or Z1202, who has probably done the most out of anyone to bring this technology to the masses (at least his paper seems to be very well know and often quoted in Audio DSP discussions). Vadim, the same guy who is being harassed here by Andy, who you defend, whilst you bleat on about the "exclusory" nature of TPT filters.

are they in some secret vigilant club, appearing out of nowhere to protect our innocent eyes?

Seek help, immediately.

This topic is mostly about woolly marketing terminology and the need to highlight the truth. I am quite serious in saying that almost any developer can quite rightly add a marketing bullet point "featuring delay free feedback filters", so to me this makes the terminology very confusing and almost pointless.

This thread has nothing specifically to do with Vadim, so I'm not sure why he felt the need to make so many off topic posts here.

Zero delay feedback is a very woolly term. For example you could have an identical filter implementation, one that comes from a passive filter and one from an active filter, and have identical DSP that computes the filter, and an identical bit for bit sound. But... one could be called a zero delay feedback filter and the other cannot, go figure. Please read this to see what I mean, the passive filter has no feedback but leads to an identical implementation as the active one that does have feedback:

www.cytomic.com/files/dsp/OnePoleLinearLowPass.pdf

Furthermore there is nothing to say that a filter solved with implicit integration techniques has to preserve any of the original structure of the filter being modelled. So any old direct form biquad that came from the laplace transform of a continuous filter can be quite rightly termed as a zero delay feedback filter.

So since the terminology is so woolly it is good for all concerned that these problems be exposed. Stimulating conversation about these issues is required, hence this thread.

[andy-cytomic]

So what was the point of this thread exactly appart from pure trollbaiting ?
Andy: I don't know you other than reading your posts here and on JUCE forum but it's not the first time I see you come accross as a bit of a knob, maybe you should reevalulate how you behave on public forums regardless on how right you think you are.
Personally it puts me off your products as well as your ideas and insight which is a shame as I think both are great.

If you disagree with anything I say then please go ahead and state your reasons. I choose to make a stand on this topic, I don't mind if it's not popular to do so. I have got people talking about things and have hopefully been able to shed some light on the topic at hand, that is an important result to me.

ps: the point of this thread is to highlight the problems with the terminology "zero delay feedback" when applied to describe the quality of an algorithm.

[ChiTown24]

I choose to make a stand on this topic, I don't mind if it's not popular to do so. I have got people talking about things and have hopefully been able to shed some light on the topic at hand, that is an important result to me.

ps: the point of this thread is to highlight the problems with the terminology "zero delay feedback" when applied to describe the quality of an algorithm.

then this thread would have been more useful a couple of years ago, when the topic was at fever pitch, less understood and much more negative. as xoxos pointed out. heated 0dfb arguments are pretty passé right now. unless i'm not lurking on the right forums.

[toothnclaw]

ps: the point of this thread is to highlight the problems with the terminology "zero delay feedback" when applied to describe the quality of an algorithm.

What terminology for the actual properties and perceived 'quality' of algorithms would you propose? Keeping in mind that: 1. people of differing skill levels do need to talk on these topics by using precise and descriptive terms that have been commonly accepted, and 2. any number of implementations and modifications at various levels of sophistication are doable or have been done?

I have read similar debates on the terminology that should be used when talking about the quality and 'sound' of reverb algorithms, and have come to the conclusion that it's not possible to use precise terms or enforce any kind of terminological standardization.

Hence the need for 'wooly' 'terms' that have the benefit of: 1. being fuzzy* enough to include a variety of close but differing meanings, and 2. being easily recognizable and memorizable to your average person.

* http://en.wikipedia.org/wiki/Fuzzy_concept

[Urs]

Here's the thing:

A develoepr can implement a random audio filter algorithm, even one not based on any analogue prototype. He can choose to do so with a unit delay in a feedback path as well as without any. When comparing those two implementations, the one without a unit delay in the feedback path will most certainly show superior behaviour.

Thus, by a quite simple logic, the term "zero delay feedback filter" can have an essential meaning, no matter what anyone else believes

[miedex]

this thread is even more dramatic than when Jessie Spano got hooked on diet pills