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so, i created a 3ms time delay convolution (did this at 400hz for the scala)


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I forget which thread it is now....but an article was posted where the bass bin was measured to have a 7ms delay.

Theoretically that is plausible for the bass bin itself with an applied impulse without taking the lag of the K-400 into the equation.

You yourself said that the Khorn reproduces drums better than any other. Drum are impact sounds, if there was such a definitive smearing, they would not sound so real. I was thinking of this as I listened to Ringo beat it out on the Abbey Road album the other night.


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It is common practice in the studio to implement a crossover on a drum

hit and add reverb/delay to the lower half of the crossover. It helps

to make the drum hit take up more space and thus sound more powerful.

Of course if you add too much you'll start having double tap issues [;)]

Btw, the measurement would have to take into account the lag of the

K-400 because that's where the comparison in the test was being

performed....or was it between the bass horn and the tweeter? hmmm, i

need to go find the article again. Either way it is a difference of 1ms.

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Doc, in response to your last query, time domain issues are Absolutely at play here!

But as far as the current experiment and the speculation by many, there are several confusions.

First there is the issue of superposition. This is well understood (by some somewhere anyway!) and no experimentation is needed except as someone might want to simply see it for themselves. In other words, this is not a new subject requiring verification!

Another area is that some are attempting to analyze the perception of this issue in terms of pure classical physics and making the logical leap of what seems to be common sense you would hear 3 (or however many) discrete pulses! But in doing so, they fail to understand the role of psychoacoustics and the interplay of the human apparatus in the mix.

And the Haas effect is well known. What occurs both physically and perceptually here is well documented.BUT! Things are not well in
<?xml:namespace prefix = st1 /><?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />River City! Cause we got trouble!

And Doc, your description: The way I see it, you have 3 separate sounds happening over a period of time that together are perceived as a single instant in time, but the overall timbre changes compared to a time-aligned system because our ears detect the "average" over the time period. is pretty good! The first impulse will take precedence and gain will be increased in this averaging (dont take this as a literal mathematical average, but as far as words go we can use it!).

Thus far we are operating in the realm of classical audio/acoustics and psychoacoustics. The problem is that the connection between objective measurements and subjective experience still has a ways to go before they converge.

There is a form of time distortion occurring. But it goes further then this. And the time and frequency domains are not necessarily the limits of equivalently mapped spaces. But I am not going to try to present in 25 words what Heyser more elegantly relates.

Not only that, but speakers routinely exhibit both minimum phase and non-minimum phase regions, with many of them (as AL K mentioned) not being minimum phase at all!!!! This is Very significant, as you will recall that you CANNOT EQ a non-minimum phase signal (well, not in a sensible constructive way!!), and this is in addition to exhibiting non-linearities that are not accounted for with traditional analysis.

Also, this attempt to linearly measure driver offset is fun, but it hardly results in an accurate measurement. First, the offset is from one acoustic center to another, not the position of a voice coil or other designated part of a driver. This is EASY to measure extremely accurately with time based measurements. And for many of the dynamic drivers, the slope of the baffle does account for this albeit ONLY in the vertical plane!

And as far as drum sounds...many would be shocked to know how many times the snare of what they felt to be the definitive drum kit (of whomever!!) was not the actual snare but literally triggered and processed white noise! But let's not let all the studio secrets out of the bag! And we haven't even mentioned "ducking"!

An interesting note as ALL of the discussions completely ignore the use of time domain measurement tools which provide a plethora of information. Now its interesting that SO many simply ignore their existence, let alone their use, and thus dismiss so much info as even existing, let alone being useful, but such discussions are, lets say, less then useful.

I mean its fun to run around at night in the woods and to bump into things you cant adequately see and then to speculate and then jump to definitive dismissals that since you couldnt clearly see them they must not have actually existed! Just as so many in this thread have dismissed just about any issue with issues in time. Just think, how many have thus far said that if things happen at different times, that it doesnt matter as they will either always be distinguished as discrete events, or since they are blurred, so what?! Both are wrong, and this subject is not in dispute in more reputable circles, but we dont let that bother us here! As the primacy of feelings rules the day!

And we will run about for days, weeks, months here trying to figure out a silly program (no offense to those who have actually tried to do that!!! Quite the opposite! As the spirit of really trying to demonstrate and reproduce is a fundamental virtue!!!) But my point is that we will persist in that, but we wont take a fraction of the time to familiarize ourselves with information that will illuminate allot of what many are making ridiculous pronouncements about.

So, few will even try reading Heyser and using the tools that Davis (Sound System Engineering) clearly elucidates. And the rest are not even aware of the extensive time domain tools that exist that are mature and have been extensively used for 25 years now. Well, who am I to question such ignore-ant paradigms of ignore-ance!? Since they are clueless as to the tools and the current theory, they must be right! Especially as they derive their ideas using such advanced methods.

And no Doc and the others who have actually tried experimenting! I am not parodying you folks! I just get a kick out of the other folks who, with little or no awareness or understanding of psychoacoustics - and even basic acoustical physics - declare this a non-issue while providing no insight into the real issue. But they do have their 'feelings'!

The time domain presents some real problems that are not accounted for. Through the extensive time domain measurements, many issues are illuminated. And ironically, the room and speaker care not treated as independent issues distinct from one another. Oh yes, they can be examined and focused upon, but ultimately the speaker room interaction is a fundamental issue. And thus time domain measurements have become fundamental for use in acoustical analysis.

And cleaning up the early reflections resulting in signal; arriving within 25-35ms of the initial signal is fundamental to improving intelligibility. And psychoacoustics are a critical factor as well, as pure bench performance does not account for the interaction of device, room and person (the psycho part ;-) of the equation.

But Heyser goes much further, as you need to understand where he points with the mapping of alternate frames of reference and the fuzzy logic that is involved. And no folk, fuzzy logic is not the same as some of the convoluted nonsense that passes for reasoning that we too often see here!

But again, I will resist the intense desire to jump into a discussion of Heyser, as there is little purpose as too few even know what I am talking about, let alone what Heyser says! As while I can make comments regarding aspects of it, I cannot pretend to present the fundamentals and the detail as well as Heyser does. And he does step through both the theory as well as the practical aspects of measurement very thoroughly! And
Davis takes this and creates an even more comprehensive presentation regarding all things acoustic. But if I chose to comment on Heyser you will simply see the usual suspects run about making their usual uninformed pronouncements regarding issues they haven't even familiarized themselves with. As, after all, they do have their feelings!

So..what does it take to get people to open their eyes and minds to Heysers writings!!! And for all the state of the art thinkers here to simply catch up to where the acoustics and audio fields were 35 years ago!

There, I hope I have made enough folks mad that maybe they will consider trying to read something other then the latest marketing brochure promising the next technological breakthrough from which so many routinely learn audio and acoustics!
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Heck, if nothing else, the failure of the traditional methods to adequately account for the measured systems correlating to perception should at least pique the interest of some folks who are still thinking! As while they may complain about them, they offer NOTHING in their place!


Oh, and to amplify a concern... I can help significantly in the understanding and conceptualization of the various domains that the Nyquist and Heyser spiral display which will tie MANY heretofore unsuspected relationships which Heyser presents!

Why is Heyser's work so revolutionary? Here are several aspects without even getting into his 'proposals'!

I think some folks who can appreciate this will be amazed - especially if you have a math or an engineering background - as much of what you learned is addressed by this in a MUCH more illuminating manner - the light will definitely turn on!!!! (Even if you have just wondered what in the hell imaginary numbers are! they aren't imaginary at all! That alone is worth the price of admission!)

OH! And one more thing!! For all of you who have ever wondered about IMPEDANCE!!!! This is fundamental!! And again, it is a presentation that is SO lacking in any engineering program (unless you have had Drs. Patronis or Leach at GaTech, or at a few other unique programs) where they are intimate with Heyser's work! Impedance (reactance) will assume the fundamental role it deserves! And the phrase "impedance mismatch" will take on a life you never suspected! So if you have ever suspected that the reason a particular amplifier and a speaker sound differently and the reason was an "impedance mismatch", you will discover why this simple sounding phrase is so fundamental. And if you believe that the nominal impedance (read - resistance!) is all that is necessary, keep walking or be prepared to have your suspicions blow out of the water!

And regarding Heyser's work... I will not attempt to present an initial synopsis, as judging from the norm, so many armchair critics will then wade in and 'debate', evaluate, prognosticate and probably dismiss the concepts, not based on a thorough reading of the works themselves, but based upon an incomplete presentation of some of the ideas presented in a hearsay manner! And I find it absurd to enable such a tired exchange. I mean, how useful is a evaluation of a movie based upon a reading of a review without having actually seen the movie??? But such discussions occur here every day! But if someone has read the material and wishes to discuss it, or clarify concepts, bring it on!! Now THAT would be most refreshing!

OK, ONE final addendum! And this is perhaps the most important!

I fear that by pushing Heyser and his importance as such a source of insight and mentioning so many obtuse and, for many, intimidating topics such as imaginary numbers and impedance - subjects normally sufficient to scare the most stalwart technoid away, I may simply be scaring many away from reading Heyser!

And if this is the case, I have failed miserably!

Let me explain. Are any of you familiar with Richard Feynman? If you are, you know that not only was he was of the world's most brilliant theoretical physicists, but he was also one of the most refreshingly talented individuals at taking incredibly complex concepts and explaining them in a manner that an 8 year old could understand (after all - he did exactly that when he explained to Congress why Discovery's O-rings failed with a Styrofoam cup, a napkin, and some cold water! - too bad most of Congress operates at a 6 year old level!)

Heyser is acoustics' Feynman! He does not write to baffle you! He writes to communicate and to clarify. Oh, trust me, the math is there if you desire it, and there are a few papers regarding the mapping of topological spaces that will cause you to read a bit slowly! But his purpose is to push the math to the back and to explain the concepts in a practical manner to be understood by YOU! In plain English! He is not writing to impress you with how smart he is as he baffles you with BS!

So, please! Do not be put off by the prospects - especially if you are not technically oriented.

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FWIW: I first began reading Heyser's works over 20 years ago and I would like to join dragonfyr in encouraging those who are interested in the study of audio and psychoacoustics to read the works of those he has mentioned and ESPECIALLY the works of RICHARD HEYSER who I would also considered one of the BEST MINDS to have ever worked in these fields of study. It is very clear once you begin reading Richard Heyser's works that he was decades ahead of many! Like dragonfyr said Heyser could write/communicate on many levels and I believe it should be MUST READING for anyone really interested in these subjects!!!!

Also as dragonfyr has said the ETF program offers alot to those interested in understanding how our systems/rooms are interacting with each other and ourselves.

Please Check It Out:



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I forget which thread it is now....but an article was posted where the bass bin was measured to have a 7ms delay.

I posted the 1986 Audio Magazine Review by Richard Heyser which gives the Time Delay between drivers.

lol, go figure...was I right about the 7ms? I'm bad with numbers so I wouldn't be surprised it if was different.

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I had to laugh when 6000 words into Dragon's long post I saw a new paragraph that began, "Let me explain..."


Such is life when someone dares to suggest that the world is round to a cadre of experts who are so deep in thought pondering the exact location of the world's edge to 17 decimal place precision.

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