the chronicles of the coyotee-o and miketn khj's (klipschorn jubilee)

[Daddy Dee]

Coytee,

I was wondering, have you ordered your Jubilees with a veneer front and grill cloth on the sides of the bass bin?

[Guest " "]

previously posted on a different thread

KPTKHJKPT402K69A.pdf

[Coytee]

Coytee,

I was wondering, have you ordered your Jubilees with a veneer front and grill cloth on the sides of the bass bin?

I was unaware of the side covers being an option. I'm mixed on them too, I kind of like looking down it's throat, as well as the 402's throat.

Mine are ordered just as you see in my avatar.

Function over form baby!!! The great divide between my wife & myself. She'll deal with almost anything as long as it's pretty, even at the expense of function, or ease of use. I on the other hand, can deal with anything as long as it works as advertised FIRST. If it happens to be pretty second, that's ok. If it's ugly as sin but does it's job, then I'm ok with that. (she can't see any beauty in a chainsaw, Klipschorn, Jubilee whereas I can see the beauty in all of them)

Now, this thread DOES have me wondering something...

I think I've realized that we all have a bit of voyeur in us as we watch these speakers march down the assembly line??

[mark1101]

To Al Klappenberger:

Maybe a dumb question but is there a way to implement a delay in a passive network?

[Al Klappenberger]

Mark,

is there a way to implement a delay in a passive network?

The simple answer is NO!

All that can be done is "group" delay all-pass netwroks and what is needed is "time" or "Propogation" delay. They are two very different things.

AL K.

[Daddy Dee]

Coytee,

Yeh, the grill covers may indeed not be an option. Just a wondering. I think the form/function Jubilee in your avatar will be quite nice.

[Jay481985]

I just wonder if the grill cover was made for presentation and non functional as they might restrict the horns somehow while their cranked up loud? It is for the bass bin which moves more air than say the mid horn of the khorn

[DrWho]

Grills will actually have less of an effect with the lower frequencies than the higher frequencies. And at very low frequencies the grill just acts like part of the air and moves back and forth as if it were air molecules. In my acoustics class we predicted the net losses to be on the order of 0.01dB...definetly not something to worry about []

[djk]

"Maybe a dumb question but is there a way to implement a delay in a passive network?"

Yes, for Cornwall and Heresy type speakers. It is called an all-pass filter, and is used to delay the signal to the woofer. It can make the midrange sound better.

[Jay481985]

Grills will actually have less of an effect with the lower frequencies than the higher frequencies. And at very low frequencies the grill just acts like part of the air and moves back and forth as if it were air molecules. In my acoustics class we predicted the net losses to be on the order of 0.01dB...definetly not something to worry about []

Oh I know grills have less effect on the lower frequencies but the fact that low frequencies also means more air being pushed, which might push the grill enough to make it fall off or flap causing noise? or it might rattle

[Al Klappenberger]

Again: An all-pass group delay equalizer can NOT be used to compensate for time delay in a woofer! Group delay is N O T time delay!

Attached is the analysis and design of an all-pass section desinged for 3 mSec. Notice it has nearly 1 dB of loss and it;s group (not time) delay is on 3 mSec at on point. To equalize the time throuhg a woofer you would need a long string of them with the peaks all in a row across the woofers range. Look at the complexity and the insertion loss! To make matters worse, since group delay and time delay are not the same thing you would find that the actual time delay would be much less! It WILL NOT WORK!

Al K.

[DrWho]

the group delay and the phase delay are identical, and each may be interpreted as time delay

For any phase function the group delay may be interpreted

as the time delay of the amplitude envelope of a sinusoid at

frequency [61].

http://ccrma.stanford.edu/~jos/filters/Group_Delay.html

Seems to me that as long as the phase response is linear (which it

is for a direct radiating driver) that the group delay results in an effective time-delay.

[Al Klappenberger]

GUYS!

PLEASE, let's not let this thread get side-tracked on the group delay thing! The KHJ subject with Roy's input is far to important a discussion for that!

The difference between group delay and time delay has been gone over many times and the vast majority of people do not understand it. Group delay is nothing more than a way to measure and quatify phase linearity over frequency shifts. It is the derivitive of phase. Let's let it go at that!

Al K.

UPDATE: I just realized that my example all-pass network above is shown at woofer frequency. The woofer has more delay than the squawker, so the equalizer would be in the squawker. This would result in an even more pronounced peak with steeper slopes if you designed it for the same group delay at a higher frequency.

BTW: A direct radiator does NOT have flat group delay becasue it is not phase-linear! It does have lower time delay though becasue it is closer to you. In that case, you would need to delay it rather then the squawker becasue the squawker would then be farther away from you!

[djk]

Sorry for the thread-jack. The Jubilee, Klipschorn/Belle/LaScala can be time aligned with a digital delay in the electronic crossover. The Cornwall/Heresy type speakers can use an inexpensive all-pass delay in either a passive or an electronic crossover.

People bought their UREI monitors with passive time-align networks because they sounded better than the same Altec drivers without time-align. People buy Bag-End speakers with passive time-align networks because they sound better than the same EV drivers without time-align.

I learned how to design passive time-align networks by reverse engineering some PAS time-align monitors. The UREI use the same basic ideas, but use bi-filar tapped inductors and half the number of caps for the same results. B&W uses this same bi-filar tapped inductor scheme in some of their networks. I have not seen a Bag-End network. Bag-End claims time-alignment within ±25 microseconds at the crossover point.

Some experiments:

SPEAKER ALIGNMENT AUDIBILITY

The purpose of the first experiment was to determine people's ability to hear time offset of a woofer and tweeter. The test setup is shown in Figure 1. Left and right channels were treated identically. The signal from either channel first is divided into high-pass and low-pass by a 6 dB / octave unity sum crossover at 1 KHz. A high quality crystal time base digital time delay unit with delay either 1, 2, 3, or 4 milliseconds is inserted in the high-pass path. An analog time delay unit with delay adjustable via an uncalibrated 10-turn control from 0.3 to 10 milliseconds is inserted in the low-pass path. The high- and low-pass signals are then amplified and fed to two identical stacked full range speakers (Phillips AD5061s). Thus in the full stereo system we have four identical speakers. Each side has the lower speaker assigned to be the woofer and the upper assigned to be the tweeter.

Using music of the listener's choice, the listener is asked to find the setting of the 10-turn control which produces the most natural blend of woofer and tweeter. Technically, the task is to match the acoustic position of the woofer and tweeter by matching the time delays.

Since the listener does not know the setting of the digital delay or the relationship between the analog unit's control rotation and its delay, (it is quite non-linear), the only clue to proper alignment is sound. (The knob was even loosened from the shaft and rotated between trials.) Since no one knows the correct setting in advance the experiment is double-blind. After the listener is satisfied with the setting, a frequency counter is connected to measure the clock frequency of the analog delay. From this the actual delay is calculated.

Despite the possibility of "digital effects," the modest quality of the speakers, and the fact that the listeners were in effect being tested, every one of approximately 12 participants was able to match the time delays to within +/- 40 microseconds (about 1/2 inch). This finding confirms the clams of those who espouse the virtues of arrival time compensated loudspeakers.

[Al Klappenberger]

djk,

That experiment is testing a person's abiltiy to hear each single component of a waveform TWICE. If a 6 db / octive filter was used there is a huge overlap where both drivers are making the same sound. If the two are out of time you hear each component twice. That casues a smear at low delay errors. Time alignment would be necessary. If, on the other hand, an extreme-slope network was used, each driver would make only the components (overtones) of the spectrum assigned to it. You would then NOT be able to hear the time errors because you ear is deaf to phase errors between components of a complex waveform. Time alignment would no longer be necessary.

I proved that to myself by mixing together 3 seperate stand-alone sine-wave signal generators together to create a simulated square wave of 1, 3 and 5 Khz in the proper proportions. I listend to the combination through headphones while watching the sum on an oscilloscope. The waveform squirmed through all possible phase relationships of the three as I watched and listnened. Even while watching the scope for visual clues the sound was a continuous raspy tone. I (at least) can NOT hear phase (time) relationships between the fundamental and the overtones.

BTW: again, I would love to hear Roy's thoughts about this. PLEASE!

Al K.

[colterphoto1]

yes ENOUGH, give Roy back his thread....

[Duke Spinner]

good point, Al

I understand the average person can hear 3 ms.

[bodcaw boy]

sorry guys....went out of town yesterday....the continuation of the build...

here is frank putting the angle cuts on the boards....

[bodcaw boy]

and now the parts go to joe beasley and yes he is related to mike beasley the qc guy. joe builds our cinema boxes....

[bodcaw boy]

and then mike m, a qc guy, comes over and checks the build with joe and helps out. a rare moment....mike m at work.....