Klipschorn Jubilee (Babies First Sounds)

[bodcaw boy]

Hey Roy!

I've got a question for you and would be very interested in your thoughts/reasons about this!

I was playing with the ETF Test Program for a short time today and noticed that you intentionally didn't bring the drivers into perfect time alignment. I assume you decided to do this after taking into account the individual Horn's Frequency Responses and Phase Responses and choose a Time Difference that provided the best Crossover "Transition Blend" Between Drivers.

mike tn[]

miketn,

interesting question and i was wondering if you were going to stumble on to this. when i started to get time of flight info for all our cinema systems, i wanted to make sure that the data we gave out for crossover freq, delays, gain, etc, would indeed give the theater curve that would require very little adjustement out in the field. so i decided to verify everything in our chamber. i entered the time of flight (or impulse time or time of energy arrival or whatever) and the other info into the ev and noticed that the lf and mf were not adding up correctly. in fact, there was interference. i wondered why that was the case since i had my time of arrival for each section. i double and triple checked that number but still we had amplitude interference. then i stumbled upon something. the electronic filters have phase sift, the drivers have phase shift, the horns phase shift and i am sure that some kid in the dominian republic is adding some sort of phase shift. what i ended up with was that that also had to be compensated for and that stuff like croossover rolloff (12 db per octave or 24 db per octave) changed what that value was. so within +/- one half the time period of the crossover frequency, you can adjust the time delay in order to get max amplitude and have very little interference. that is why i am so glad, we have a chamber; that allows me to instantly change the delay value and see what happens.

having the time of flight gets you within the right time period of the crossover freq. knowing that other phase shifts are occuring but not knowing there value is why the time delay is adjusted until max amplitude is achieved. this lowers interference possibilities but puts the sections together so that the acoustic wave exits both sources correctly.

hope that my feeble attempt to explain this makes sense.

berryboy roy

Thanks Roy!

I believe I understand your point pretty well. So basically your making the best of an imperfect world and Time is another Variable at your disposal to make the best response through the overlap band of the two horns and just not at the exact crossover frequency.

So my next question 'Good Teacher" Roy!, At what distance and height was your Measurement Mic so that I can reproduce some of what you saw with the ETF Program?

mike tn[]

hey miketn,

i was about 3 meters away and on tweet axis. i will see if i can find the chamber curve and pass it on to you. email me at work so i don't forget.

berryboy roy

[bodcaw boy]

Is it possible to introduce independant phase adjustments on this crossover? I'm not exactly sure how normal phase knobs work so don't know if they by nature introduce time-delays of their own???

One thing that strikes me as rather interesting is that Roy is trying to maximize the efficiency of the system through the crossover region - I done learned in Hope that Klipsch puts efficiency as #1 on their priority list. And then I was thinking about it a little more, wondering about the compromises involved (yes, my head hurts....). By absolutely maximizing the efficiency of the sysem over the crossover region you also minimize the amount of overlap between drivers while maintaining a flat frequency response. Minimizing overlap is a good thing because it reduces the magnitude of timing issues in the vertical plane (the drivers are physically spread out so there is a corresponding delay and phase shift).

And assuming that line of reasoning is somewhat accurate, I suppose it would make sense that pattern control is needed so low for the HF driver (something I've been wondering about). The acoustical centers of the two sections are rather far apart....too far for a "clean" 1kHz crossover (isn't the general rule of thumb to be within a 1/4 wavelength?). I'm pretty sure the bass bin is rather narrow in the vertical so a narrow vertical for the tweeter would be following general line array principles - the less overlap, the less comb-filtering off-axis (again only an issue in the vertical plane).

I know it's all speculation, but I find it interesting how conceptually a lot of other things start to fall in place when you try to optimize efficiency. I always hear about how PWK was always talking about efficiency all the time and I think I'm beginning to see why. I don't think it's just about the raw output and dynamic capability of the system (thought that is certainly a great attribute).

Enough rambling. And hopefully if I'm way off base Roy will put me back in line with a Herring in the traditional Monty Python style []

hey doc,

you are getting it. efficiency, sensitivity, smooth polar transition, even coverage patterns...it all matters and how much of each is important.

for the active unit, i choose and acoustic crossover of about 550 Hz. that is about the low end of the coverage pattern overlap of the two horns. look at the data i sent and see if it makes sense to you.

berryboy roy

[bodcaw boy]

Is it possible to introduce independant phase adjustments on this crossover? I'm not exactly sure how normal phase knobs work so don't know if they by nature introduce time-delays of their own???

One thing that strikes me as rather interesting is that Roy is trying to maximize the efficiency of the system through the crossover region - I done learned in Hope that Klipsch puts efficiency as #1 on their priority list. And then I was thinking about it a little more, wondering about the compromises involved (yes, my head hurts....). By absolutely maximizing the efficiency of the sysem over the crossover region you also minimize the amount of overlap between drivers while maintaining a flat frequency response. Minimizing overlap is a good thing because it reduces the magnitude of timing issues in the vertical plane (the drivers are physically spread out so there is a corresponding delay and phase shift).

And assuming that line of reasoning is somewhat accurate, I suppose it would make sense that pattern control is needed so low for the HF driver (something I've been wondering about). The acoustical centers of the two sections are rather far apart....too far for a "clean" 1kHz crossover (isn't the general rule of thumb to be within a 1/4 wavelength?). I'm pretty sure the bass bin is rather narrow in the vertical so a narrow vertical for the tweeter would be following general line array principles - the less overlap, the less comb-filtering off-axis (again only an issue in the vertical plane).

I know it's all speculation, but I find it interesting how conceptually a lot of other things start to fall in place when you try to optimize efficiency. I always hear about how PWK was always talking about efficiency all the time and I think I'm beginning to see why. I don't think it's just about the raw output and dynamic capability of the system (thought that is certainly a great attribute).

Enough rambling. And hopefully if I'm way off base Roy will put me back in line with a Herring in the traditional Monty Python style []

hey doc,

you are getting it. efficiency, sensitivity, smooth polar transition, even coverage patterns...it all matters and how much of each is important.

for the active unit, i chose an acoustic crossover of about 550 Hz. that is about the low end of the coverage pattern overlap of the two horns. look at the data i sent and see if it makes sense to you.

berryboy roy

[mikebse2a3]

Hey Roy!

I've got a question for you and would be very interested in your thoughts/reasons about this!

I was playing with the ETF Test Program for a short time today and noticed that you intentionally didn't bring the drivers into perfect time alignment. I assume you decided to do this after taking into account the individual Horn's Frequency Responses and Phase Responses and choose a Time Difference that provided the best Crossover "Transition Blend" Between Drivers.

mike tn[]

miketn,

interesting question and i was wondering if you were going to stumble on to this. when i started to get time of flight info for all our cinema systems, i wanted to make sure that the data we gave out for crossover freq, delays, gain, etc, would indeed give the theater curve that would require very little adjustement out in the field. so i decided to verify everything in our chamber. i entered the time of flight (or impulse time or time of energy arrival or whatever) and the other info into the ev and noticed that the lf and mf were not adding up correctly. in fact, there was interference. i wondered why that was the case since i had my time of arrival for each section. i double and triple checked that number but still we had amplitude interference. then i stumbled upon something. the electronic filters have phase sift, the drivers have phase shift, the horns phase shift and i am sure that some kid in the dominian republic is adding some sort of phase shift. what i ended up with was that that also had to be compensated for and that stuff like croossover rolloff (12 db per octave or 24 db per octave) changed what that value was. so within +/- one half the time period of the crossover frequency, you can adjust the time delay in order to get max amplitude and have very little interference. that is why i am so glad, we have a chamber; that allows me to instantly change the delay value and see what happens.

having the time of flight gets you within the right time period of the crossover freq. knowing that other phase shifts are occuring but not knowing there value is why the time delay is adjusted until max amplitude is achieved. this lowers interference possibilities but puts the sections together so that the acoustic wave exits both sources correctly.

hope that my feeble attempt to explain this makes sense.

berryboy roy

Thanks Roy!

I believe I understand your point pretty well. So basically your making the best of an imperfect world and Time is another Variable at your disposal to make the best response through the overlap band of the two horns and just not at the exact crossover frequency.

So my next question 'Good Teacher" Roy!, At what distance and height was your Measurement Mic so that I can reproduce some of what you saw with the ETF Program?

mike tn[]

hey miketn,

i was about 3 meters away and on tweet axis. i will see if i can find the chamber curve and pass it on to you. email me at work so i don't forget.

berryboy roy

Hey Roy

The Tweeter axis is so high and I know you can never account for all possible listening positions (vertical angles) but just wondering why not use a height of close to 1 meter since this is closer to where most listeners would be in a Home Enviroment. I know that the polar responses are Very Well Behaved (Anyone who thinks the K402 might be beamy should see These Plots!!! This has got to be one of the smoothest and well controled Horns that I've Seen and Heard!) so between that and the Time Window you have maybe it isn't necessary but it does make me wonder!!!

mike tn[]

[mikebse2a3]

Is it possible to introduce independant phase adjustments on this crossover? I'm not exactly sure how normal phase knobs work so don't know if they by nature introduce time-delays of their own???

One thing that strikes me as rather interesting is that Roy is trying to maximize the efficiency of the system through the crossover region - I done learned in Hope that Klipsch puts efficiency as #1 on their priority list. And then I was thinking about it a little more, wondering about the compromises involved (yes, my head hurts....). By absolutely maximizing the efficiency of the sysem over the crossover region you also minimize the amount of overlap between drivers while maintaining a flat frequency response. Minimizing overlap is a good thing because it reduces the magnitude of timing issues in the vertical plane (the drivers are physically spread out so there is a corresponding delay and phase shift).

And assuming that line of reasoning is somewhat accurate, I suppose it would make sense that pattern control is needed so low for the HF driver (something I've been wondering about). The acoustical centers of the two sections are rather far apart....too far for a "clean" 1kHz crossover (isn't the general rule of thumb to be within a 1/4 wavelength?). I'm pretty sure the bass bin is rather narrow in the vertical so a narrow vertical for the tweeter would be following general line array principles - the less overlap, the less comb-filtering off-axis (again only an issue in the vertical plane).

I know it's all speculation, but I find it interesting how conceptually a lot of other things start to fall in place when you try to optimize efficiency. I always hear about how PWK was always talking about efficiency all the time and I think I'm beginning to see why. I don't think it's just about the raw output and dynamic capability of the system (thought that is certainly a great attribute).

Enough rambling. And hopefully if I'm way off base Roy will put me back in line with a Herring in the traditional Monty Python style []

hey doc,

you are getting it. efficiency, sensitivity, smooth polar transition, even coverage patterns...it all matters and how much of each is important.

for the active unit, i choose and acoustic crossover of about 550 Hz. that is about the low end of the coverage pattern overlap of the two horns. look at the data i sent and see if it makes sense to you.

berryboy roy

Just to ad a little more info. Roy has us setting the EV Crossover at 500Hz Electrically and I believe this shows that, bottom line that it is important what is happening Acoustically and not just Electrically to optimize the speaker.

So in the region around 550Hz the coverage angle is approximately:

KPT-KHJ-Lf has a coverage angle of 38H x 85V Degrees

The K402 has a coverage angle of 75H x 80V Degrees

mike tn[]

[Mr. Widget]

Since no one has mentioned it, I assume you are not using curves Roy

has taken from the chamber to EQ the systems for a more linear FR

curve... that EV crossover seems to be a pretty powerful tool and it

would seem that since Roy is in a position to get real anechoic

measurements of the Jubilee, that would be a fantastic opportunity.

I know that EV supplies that sort of data for their systems, but I

don't know if there is a way to input your own curves into the device.

Widget

[mikebse2a3]

Since no one has mentioned it, I assume you are not using curves Roy has taken from the chamber to EQ the systems for a more linear FR curve... that EV crossover seems to be a pretty powerful tool and it would seem that since Roy is in a position to get real anechoic measurements of the Jubilee, that would be a fantastic opportunity.

I know that EV supplies that sort of data for their systems, but I don't know if there is a way to input your own curves into the device.

Widget

Well I was going to post just the 4 pages of theVertical and Horizontal Coverage Graphs for the KPT-K402-HF and KPT-KHJ-LF but the forum want let me tonight so maybe tomorrow.

Hi Mr. Widget

Actually we are using the Paramaters that Roy suppilied from the chamber measurements to setup the Jubilees crossover points and EQ needs and yes we can also setup our own user programs such as Roy's Program as well as any we want to do up to 30 Programs.

mike tn[]

[Mr. Widget]

So in addition to time alignment (phase) and crossover

slopes and frequencies, you do have the parameters to either manually

or automatically set the parametric filters to set the speaker to a

fairly flat anechoic frequency response? Was Roy able to set up a RACE

file to set these parameters or is it something you have to enter manually?

Widget

[DrWho]

Thanks Roy!

I must confess never having seen such elaborate plots before which makes it hard to compare against other speakers I've heard and seen the measurements for, but after a very quick browse (basically looking at each page for a second) things look rather impressive.

One thing I've always wondered about is why the polars aren't perfectly symmetrical - especially with the rear polars. Is this the product of assymetries in the anechoic chamber or issues with noise floor? Rounding errors with the program? Wobbling of the speaker on the turntable? That kid in the dominian republic? It's more of an academic interest because it shouldn't really effect how one interprets the data.

And how can the on-axis response be lower than just slightly off-axis at some frequencies? That blows my mind - doesn't that imply a planar wave front?

I think we need to start a "get doc some jubilees fund" - or maybe I need to get one of those cardboard signs with strings: "will work for jubilees" []

[jwc]

Doc. You are changing your tune. Are you now getting sucked into the bass horn craze?

[mikebse2a3]

So in addition to time alignment (phase) and crossover slopes and frequencies, you do have the parameters to either manually or automatically set the parametric filters to set the speaker to a fairly flat anechoic frequency response? Was Roy able to set up a RACE file to set these parameters or is it something you have to enter manually?

Widget

Well I entered the info manually which is very easy once you get use to the EV Dx38 and yes the Time Alignment, Crossover Frequency, and Parametric settings I'm using now are based on Roy's Measurements.

I think Roy did a spread sheet for Richard but to be honest I haven't taken the time to look at the Race file Option myself.

mike tn[]

[mikebse2a3]

Thanks Roy!

I must confess never having seen such elaborate plots before which makes it hard to compare against other speakers I've heard and seen the measurements for, but after a very quick browse (basically looking at each page for a second) things look rather impressive.

One thing I've always wondered about is why the polars aren't perfectly symmetrical - especially with the rear polars. Is this the product of assymetries in the anechoic chamber or issues with noise floor? Rounding errors with the program? Wobbling of the speaker on the turntable? That kid in the dominian republic? It's more of an academic interest because it shouldn't really effect how one interprets the data.

I wonder if it isn't related to the Horn Structure itself vibrating and thus sending some of the sound to the rear? Either way most of it is 18 to 30db down in SPL in the case of the K402. Anyway I've seen this often on Plots like these and the other difference is Roy sent us some very High Resolution Test where as usually manufactured advertised test like these are at maybe 1/3 octave frequencies at best.

And how can the on-axis response be lower than just slightly off-axis at some frequencies? That blows my mind - doesn't that imply a planar wave front?

I'm not positive but I believe they normalize all frequencies to the (0 db) level and it doesn't matter at what angle it occures at and then relate it to the -6db point for their Angle of dispersion Rateing.

I think we need to start a "get doc some jubilees fund" - or maybe I need to get one of those cardboard signs with strings: "will work for jubilees" []

mike tn[]

[mikebse2a3]

KPT-402-HF Horizontal Coverage

[mikebse2a3]

KPT-402-HF Vertical Coverage

Remember Roy is crossing over at approximately 550Hz Acoustically.

[mikebse2a3]

Jubilee KPT-KHJ-LF Horizontal Coverage

[mikebse2a3]

Jubilee KPT-KHJ-LF Vertical Coverage

All these I believe are referenced to the -6db point for the coverage angle shown.

[Al Klappenberger]

mikebse203,

Those curves confused the tar out of me at first! Could it be that the vertical axis marked "dB" should be really be marked 0-360 degrees?

Al K.

[freddyi]

Hey AL and guys - pardon my ignorance - which horn lens (tractrix-?) is shown here on top of Jubilee?

[Mr. Widget]

mikebse203,

Those curves confused the tar out of me at first! Could it be that

the vertical axis marked "dB" should be really be marked 0-360 degrees?

Al K.

I sure hope so![]

Widget

[mikebse2a3]

mikebse203,

Those curves confused the tar out of me at first! Could it be that the vertical axis marked "dB" should be really be marked 0-360 degrees?

Al K.

Hey Al

Yes the vertical scale is 0-360 degrees and the curve represents the coverage angle acheived until the response drops to -6db relative to the 0db reference level that all frequencies are normalized to for the coverage angles of the Horns.(The db part of the vertical scale should probably say -6db for the angle shown). The actual coverage plots info is much more detailed than these charts show but I can tell you these Horns coverage angles are for the most part very smooth behaving in the frequency ranges they are used in.

mike tn[]