Is there any timedelay compensation in the Khorn between the bass re the mid re the tweeter

cwm · December 28, 2004

Scroll down to the section "Psychoacoustics" subsection #4 and listen to the various delays especially the first 10 millisecond sample........

RJP

http://sig.sapp.org/sounds/wave/00readme.html

jlossint · December 28, 2004

Thank you all for your contributions to my question.

Using steep filter certainly will solve some problems, but the delay will still be there between the bass, midrange and tweeter and this will produce unwanted lobing effects to the sound.

I know this because I have done experiments with it.

In a two-way horn system, very much like a Belle Klipsch. The bass unit was working up to about 800 Hz and from there it used a Pioneer horn, the PD/PH-50, which worked from 800 to about 20 kHz. There was a clear difference when moving the Pioneer horn backwards, compensating for the different path lengths. In the usual setup, like a Belle K, and using pink noise as sound. The sound image from one loudspeaker was like coming from to distinct sources, the lower part and the upper part. Moving the Pioneer horn backwards the sound suddenly appered like one source, impossible to say that itcame from as specific part of the loudspeaker. The effect it had on the sound can most easily be described as reduced "harshness" to the music. Also the stereo image was much improved. This harshness is also described as "horn sound". I should also add that the x-over was the most simple, a first order, but it should be possible with any higher order Riley-Linkwitz x-over networks.

My question still remains, is there any experiments with lattice-networks or similar to compensate for the timing difference

?

Al Klappenberger · December 28, 2004

"Using steep filter certainly will solve some problems, but the delay will

still be there between the bass, midrange and tweeter and this will produce

unwanted lobing effects to the sound."

Yes, but as I point out before, YOU CAN'T hear it! The delay difference is

not enough to be audible between woofer and squawker. It only amounts to

phase. In the tweeter the wavelengths are only about 1 inch long. The tweeter

and squawker driver would need to be at exactly the same place within a

fraction of an inch in EVERY PLANE to be time aligned enough to stop lobing!

*****

"In a two-way horn system, very much like a Belle Klipsch. The bass unit was

working up to about 800 Hz"

NO! The Belle Klipsch is three-way and the crossover is supposed to be 500

Hz. The Belle woofer starts to roll off at 700 Hz that would be the crossover

with the AB network since it runs the woofer full range. The tweeter

crossover is about 6000 Hz.

*****

"Is any of our ability to hear phase or time differences is in any way

dependent on the orientation (vertical or horizontal) of the two sources?"

Yes, I think so, otherwise we would not be able to determine between an

object flies over our head from one that passes to the left or right of us.

More important is the interaction between drivers. Think of simple

trigonometry and imagine a right triangle. The distance between sources in

any plane (including vertically) is side "A". The distance to the listener is

side "B". Both dimensions determine the hypotenuse. As you move around the

room the geometry changes. Remember too that you will then not be standing

square-on to the front of the speaker. Now the triangle is no longer a simple

right triangle but has random angles. You have a royal mess when two driver

are making the same sound!

****

"Of course, 99.9% of the time the drivers will never reproduce the same

frequency at the same level, but I'm just speaking hypothetically here"

WRONG! With a first order filter on the tweeter (6 dB / octave like the

Klipsch type "A" network) the tweeter filter attenuates 6000 Hz by about 3

dB. The attenuation does not reach 10 dB until all the way down to 2000 Hz.

This is the level where I assume the interaction stops. The K77/T35 tweeter

will make a sound all the way down to about 3500 Hz. This means the tweeter

and squawker are playing the same sound sufficiently to interfere with each

other from 3500Hz to where the K55 squawker driver poops out. That turns out

to be about 7000 Hz! I would call 3500 to 7000 Hz far from not 99% of the

time! In contrast, my ES5800 network has a 10 dB interference window that

extends only from 5500 to 6000 Hz.

Al K.

sfogg · December 28, 2004

" Using steep filter certainly will solve some problems, but the delay will still be there between the bass, midrange and tweeter and this will produce unwanted lobing effects to the sound."

To have lobing the drivers need to be reproducing the same material. If they aren't doing that (ala *steep* crossovers) they won't having lobing effects.

I know because I've tested this myself. With the steep crossovers (around 150dB/octave initially) you can stand in front of the speaker playing pink noise and move around vertically (changing the path length differences) and the sound really only changes when you get outside of the coverage of the horns.

With the first order crossovers in the same speaker the sound changes quite a bit as you move around vertically because of the interference (lobing) between the drivers.

Al mentioned...

" my ES5800 network has a 10 dB interference window that extends only from 5500 to 6000 Hz. "

With the ES600 networks I'm using that window is only about 50hz wide.

Shawn

djk · December 28, 2004

"My question still remains, is there any experiments with lattice-networks or similar to compensate for the timing difference"

Bravo for you!

The 'offical' line here is of course PWK's, and he couldn't do anything about it so he delared it didn't exist.

I have had the exact same experience as you have. It is plainly audible.

I have built many speakers with all pass delay networks and this really works. But is only practical for shallow woofers and deeper horns.

The UREI studio monitors are a good example of this.

B&W uses all pass delay networks on some of their tweeters. The delay involved is only a fraction of an inch. Still, it takes so many sections that they transform the X configuration of the inductors to a single inductor with five taps, and only need half the number of caps.

The Behringer digital crossover allows you to try it yourself for less than what an assembled ALK network sells for. Most people have an extra amp laying around so that won't be an issue. If you need a cheap HF amp for the tweeter, some here like the little Tripath 10W class D amplifier. They can be has on-line for as low as $30.

There is another solution that sounds better and costs less. If you're interested you can send me an e-mail. Its pointless to discuss here, the natives will get restless.

It also solves the aparent apex problem (lobing).

Deang · December 28, 2004

Send you an email? Hell, you're worse than me answering those things!

JJkizak · December 28, 2004

Speaking of phasing--- In 1969 I made a recording with an Ampex deck with two Shure 360 degree mics placed 2.5 ft from the K-horns even with the midrange horns of a party at my house. The living room was open ceiling and "L" shaped with windows and hallways and opening into a kitchen. The K-horns were in corners 25 ft apart with a power derived Cornwall center channel using a Fisher tube amp. When we played back the tape at acceptable volume the result was absolutely fantastic. The phone rang and everybody in the room went to answer the phone until somebody did and there was dialtone, then realizing the phone was recorded on the tape. All people sounds walking around the room were in their exact position no matter where you stood listening to the tape. If this technique could be duplicated electronically to all of recorded music it would blow away 7.1 systems as you would only need 3 speakers and a room template phasing reference to install into your system. In my mind this is the future.I have never heard anything anywhere to duplicate this.

JJK

cwm · December 28, 2004

"The 'offical' line here is of course PWK's, and he couldn't do anything about it so he delared it didn't exist."

???? Well I gather most people on this forum haven't had the privilege of "standing on PWK's shoulders".(sic) A little bit of humility can enhance the technical points one is trying to make...........

Deang · December 28, 2004

I've actually seen Dennis several times mention the advantage of "standing on PWK's shoulders" -- using those words exactly in fact.

The real secret to working around this issue is listening to God awful recordings of God awful music.

D-MAN · December 28, 2004

PWK mentioned in an article that he was standing on the shoulders of giants to come up with the Klipschorn.

Then he started naming names and citing examples.

Class act. I swear, the more I find out about him, the more impressive a personage he becomes.

DM

WMcD · December 28, 2004

I can't quite agree with 3dzapper.

I'm unaware of any passive, or active delay in a TV set. The transmission and processing of the audio and video just don't take much of a difference in time. But I'd be more than happy to see any technical literature.

One thing I have read about is the set up in movie theaters. The speaker is behind the screen and the average viewer may be 100 feet out into the hall. There is some adjustment to make the sound come out early so that it arrives at the middle of the hall (the speed of sound) at the same time as the photons (speed of light) from the screen.

Of course in the old days that may have been part of the mix in the film. Remember (if you were a high school nerd like myself) that the film goes through the gate behind the lense, but only later goes past the optical pickup for the sound. (If I have that correct.)

Now with film audio on a CD in some set ups, there must be something different.

I've watched TV movies where the film is dubbed to video tape. Only once did I think I saw a time offset. Maybe it is cleaned up. Of course this is a matter of timing the entire audio signal. I'll have to watch some karate movies. Smile.

- - -

In the K-Horn, I think the delay issue is overstated. It may show up on impulses. Most of those must be in the midrange, not withstanding theory.

In my experience, the woofer played alone doesn't contribute much alone. Contrary to what's been described by others, playing the woofer alone, though the crossover, results in very muffled sound. Of course it is wonderful in combination with everything else.

Also, the tweeter alone doesn't seem like much either. Very scratchy limited. Note is mostly working over 1.5 octaves.

This just goes to show how much of the critical signal is being handled by the mid. A little twinkle early or a little boom late may not make much of a contribution.

Gil

jdm56 · December 28, 2004

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On 12/28/2004 8:25:30 AM Al Klappenberger wrote: