Time-Alignment for Folded Horns (Patent)

[Marvel]

In fact, if you listen to

some modern hip music with the drum machine bass drum track (with the

beats monotonously pounding on the 1 and 3 beat like a demented march)

you will notice that the programmer DID evoke and execute an approach

to time alignment by virtue of the way the midi score is composed. The

result, if you listen, is that the drum beats are slightly too early

giving the effect of a drummer playing a little faster than the rest of

the "band".

Hope this helps.

Paul

Real drummers do the same thing, depending on the style of music. I

used to have an article explaining this, but it's buried in a spare

room at the moment.

Bruce

[DrWho]

And the khorn that delays the bass will only further magnify these issues...

If the perfect speaker has some of this delay, then it will certainly be accounted for in the way the music was mixed in the studio....then when we play it back, our speakers need to accurately track what was put down on the recording, not further increase the magnitude of bass delay. Like you said, the musicians (or DJ) are already compensating for this in the way they play (mix). I guess what I'm trying to say is that just because the "zero point" doesn't occur at zero, doesn't mean that further shifting away from the "zero point" is acceptable, let alone a good thing.

Delaying part of the waveform is also going to introduce all sorts of phase shifts as well, which will certainly be audible to the ear. With any two frequencies there are sum and difference tones that occur (so with a 50Hz and 400Hz tone, we will also hear 250Hz and 450Hz). So if there are a couple thousand frequencies playing at the same time, then you can imagine how quickly complex this gets. When the very first sound coming from the khorn arrives at your ear, the MF section is going to be present without the LF section being present. So for the first few ms until the LF arrives, you are going to hear the music without any of the harmonic information provided by the LF section (so you'll hear only a 400Hz tone). Then when the LF arrives slightly later, it will then interact with the MF information that is now a few ms further along in the music....thus introducing another completely new harmonic structure (The 250Hz and 450Hz tones will be shifted slightly in frequency). So with a delayed driver you are effectively introducing two harmonic structures never put on the recording. Granted the second set won't be too different considering that the amount of phase shift will be relatively small with the lower frequencies, but you still have that instantaneous 'transition' that occurs at that 8ms (or whatever the delay is). And I'm not even getting into the smearing that would happen with the stock crossovers in the crossover region (or the super steep crossovers will just make this transition even more instantaneous).

So back to the big picture, the side-effects aren't as huge as some of the other things gained by the design of the speaker (like lower FMD, increased sensitivity, a speaker that fits through doors, etc etc). But in the big picture, it is also easy to correct for the time-delay issues....especially if we have a digital source (in which case we can just actively tri-amp the system and correct for time in the digital domain). Heck, it would even be easy to remaster a CD so that the time correction is built into it, allowing a more direct signal path to the speaker (one quality ADC stage instead of three). Why try to argue about how difficult it is to hear the difference when it can so easily be corrected for without compromise?

[Deang]

Compared to what is happening with live music, the Klipschorn is an atomic clock.

[pauln]

Damn, some of us spend time and effort writing page long posts to express what DeanG pops through in one sentence.

[D-MAN]

Marvel brings up a very good point. Different drivers have different "timing". You can get a much "tighter" sound from a different bass horn driver. Personally, I find the K33E is a somewhat "fat and sloppy" driver in that it is balanced towards the low end of the spectrum and falls off rapidly, which makes the midrange driver/horn assembly responsible for the "punch" attack (I feel that the K33E lacks the quality of "punch" as its inherent trade-off for GREAT low frequency response). A 6db slope doesn't particularily help the timing "smear" as both the woofer and midrange are producing the same frequency to a degree; a problem with my horns due to their folding technique but not with the Khorn that I could hear when at the Heritage dealer. The K33E also has a "sound" that is certainly more than acceptable; it comes down to a matter of taste. It's so-called "speed" issue only became apparent to me when I started testing other drivers in the bass horns. Otherwise, I would not have noticed, but now I cannot go back to them. As a side note, I also tried the K33E's using the larger throat cavity opening size (6x13") and they bloat right out. Stay with the 3x13" slot size with the K33E.

The ESN crossover also tends to separate the "punch" portion attack completely and apply it to either the bass driver or midrange alone depending on the crossover point chosen, which greatly helps to subdue any noticable timing issues. As a bonus, any comb-filtering effects are also subdued by separating the frequency spectrum in a definite manner.

To reinforce the Klipschorn, I have heard new Khorns, and I did not "hear" anything that I would regard as a problem with the low-end. As I stated before, the midrange/bass crossover seemed to me to be flawlessly seamless. It was the finest aspect of them, I think. But I could not A/B them against my horns, so it is a comparison by memory only.

However, I am convinced that my corner horns are distinctly "faster" PERCEPTUALLY speaking for 3 reasons: different bass horn driver which is "tilted" towards the punch-side of the bass spectrum, different folding technique, and ESN crossovers crossed over at 600Hz. The percussion is astounding (I'm not kidding). A recent demo of them elicited "I have never heard a speaker do that before - I've never heard drums and cymbals sound so realistic". I specifically asked whether a sense of "lag" could be noticed, and the answer was no, which corresponds to what I think too, but a second opinion doesn't ever hurt anything. I figure if they are doing THAT right, they are doing everything else right (hopefully). Technically, the bass horn HAS to introduce a timing issue by its physics, but other elements can counter-act the detrimental effects. It is still there - but you can't hear it.

DM