A time-aligned top end - Part II

[seti]

It looks like we have what we have all been waiting for, a good two-way Khorn!

I am pleased to announce one of ouf first customers to use this horn in a 2-way is thrilled with the results.

A quote from the reviewer:

3. The soundstage is massive and almost delivers a total wrap around effect but stays focused across the listening spectrum. There is exquisite center focus imaging ...and even though the soundstage it larger than the (<<<Edit>>>) it stays tight and focused. Never gets sloppy. Another big thing is the clean character of the sound. I have two requirements clean and smooth and man I have got both.I had both before but i have even more now PROBABLY due to authority in the mid highs and highs which makes them seem more "right there in the room"

Oh dear I recognize the use of font.

This is very exciting.

[Al Klappenberger]

Lee just sent me some photos of this test setup for the polar plots. Here's two of them.

Al K.

[Rudy81]

Outstanding! No doubt, two way is the way to go. The availablity of a suitable driver and horn are making this a great possibility for the Khorn. I loved it when I tried my Khorns with my P. Audio driver and horn, but could not get as low as I needed. One of the reasons I left the Khorn....but this is great guys!

Congratulations Dave and Al.

[Arkytype]

As I e-mailed Al, it takes me longer to get the Eliptrac set squarely on the turntable and to get the mic precisely aligned than it does to make the polar measurements!

We have a 350 seat auditorium which I used to make all the Edgar and Eliptrac measurements. Both horns were "firing" into a large curtain on stage about 50 feet away.The gating of the ARTA measurement software ignores any reflections with a round trip that long anyway. More about ARTA later.

The mic capsule used is a Bruel & Kjaer 4135 1/4" which is, as PWK was fond of saying, "Flatter than a bookkeeper's arse". I used corrected frequency response curves to offset what little non-linearity the mic has. The B & K mic preamp feeds a B & K 2610 Measuring Amplifier which is flat from 2-200k Hz. The absolute level calibration is done using a Bruel & Kjaer 4220 Pistonphone calibrated with the past 12 months. Its absolute accuracy is guaranteed at + or - 0.2 dB.

The software interface is a Presonus FireBox which is a little picky about latency and sampling settings but eliminates the necessity of having to use a sound card. ARTA will work with many soundcards as well as outboard firewire interfaces.

I've been using a licensed version of ARTA for a few months now and have found it almost intuitive to use. The manual for all three sections of ARTA is on line and mixes in theory and measurement in a well-written format. The software and manual author, Dr. Ivo Mateljan, is the head of the Electroacoustic Laboratory at the University of Croatia.

http://www.fesb.hr/~mateljan/arta/index.htm

You can download a free demo version of ARTA which allows full functionality except for loading and saving data files. The license key is around $125.00 and is well worth the investment if you are serious about acoustic measurement.

Now, do you need to invest in laboratory-quality gear such as Bruel & Kjaer to measure your system? Probably not.

Parts Express has a neat USB microphone with software from Liberty Audio (Praxis) for around $300.00 that looks like a real bargain. http://www.parts-express.com/pdf/390-790b.pdf

Having measured just about anything that moves air, I've learned that it's easy enough to make a measurement. Interpreting what the wiggly lines mean, now that's a topic for another post.

Lee

[Rudy81]

3. The soundstage is massive and almost delivers a total wrap around effect but stays focused across the listening spectrum. There is exquisite center focus imaging ...and even though the soundstage it larger than the (<<<Edit>>>) it stays tight and focused. Never gets sloppy. Another big thing is the clean character of the sound. I have two requirements clean and smooth and man I have got both.I had both before but i have even more now PROBABLY due to authority in the mid highs and highs which makes them seem more "right there in the room"

Dave, do you know what driver is on this setup?

[Chris A]

Dave, do you know what driver is on this setup?

...and crossover frequency/filter type (Butterworth, Butterworth-squared, etc.)... [A]

[Guest David H]

Dave, do you know what driver is on this setup?

...and crossover frequency/filter type (Butterworth, Butterworth-squared, etc.)...

Driver = Beyma CP-750-ND

The crossover design has not been shared nor has the crossover frequency.

Crossovers are ALK's department.

[seti]

Dave, do you know what driver is on this setup?

...and crossover frequency/filter type (Butterworth, Butterworth-squared, etc.)...

Driver = Beyma BMD-750

The crossover design has not been shared nor has the crossover frequency.

Nice driver.

800hz but I don't think the crossover information will ever be shared.

[Rudy81]

Dave, isn't the BM-D750 the P. Audio driver that is just like the K69?

[Guest David H]

Dave, isn't the BM-D750 the P. Audio driver that is just like the K69?

My mistake, its the Beyma CP-750-ND

[Al Klappenberger]

Here's the crossovers he is using in the Jubes. I'm sure it's a simple gentle slope thing. I have no way to know if it's designed right or not.

Al K.

[Rudy81]

You can't really compare against an orchestra because the stage they're on is technically part of the instrument making the sound we're referring to when we say "orchestra". In other words, when the orchestra is recorded, the ambience of the environment is captured in the recording. We're not trying to create that ambient effect in our listening rooms.

What a bummer, that is exactly what I have been after in a system. Its ability to recreate the environment of the recording. Many of the audio test discs tell you about the recording environment so you can compare how it sounds in your system.

What, then, is it that we are trying to recreate with two speakers?

[Blvdre]

You can't really compare against an orchestra because the stage they're on is technically part of the instrument making the sound we're referring to when we say "orchestra". In other words, when the orchestra is recorded, the ambience of the environment is captured in the recording. We're not trying to create that ambient effect in our listening rooms.

What a bummer, that is exactly what I have been after in a system. Its ability to recreate the environment of the recording. Many of the audio test discs tell you about the recording environment so you can compare how it sounds in your system.

What, then, is it that we are trying to recreate with two speakers?

I think you're misunderstanding. We are not trying to create the recorded environment in our listening rooms, we are trying to re-create it. Therefore the listening room environment will be much different due to the differing goals of reproduction vs production.

[mikebse2a3]

Well folks, It seems the coaxial B&C DCX50 plus the 9KHz Linkwitz-Riley crossover idea that started this thread is already obsolete! With a HUGE thank you to Lee Clinton (Arkytype), we have both horizontal and vertical polar plots of the Faital pro HF200 driver on the Eliptrac 400 prototype horn. It looks like we have what we have all been waiting for, a good two-way Khorn!

Here is the polar plots all overlaid for direct comparison.

I thought it might help to extract the data in a different form to help view what this horn/driver is doing.

I used the fairly standard 6db down point as a reference point to reach these polar angles derived from the published polar graph.

FREQUENCY HORIZONTAL VERTICAL

400hz 100 degree 120 degree (approx)

1250hz 80 degree 80 degree

3150hz 54 degree 44 degree

6300hz 45 degree 25 degree

10000hz 38 degree 26 degree

12500hz 28 degree 16 degree

20000hz 44 degree 40 degree

Basically you have a horn/driver that collaspes it's polars in both the Horizontal and Vertical planes.

mike tn

[Al Klappenberger]

"Basically you have a horn/driver that collaspes it's polars in both the Horizontal and Vertical planes."

I think that's exactly what you would expect from anything but a constant-directivity horn. It's one of the criteria used to pick the crossover frequency. You pick it where the directivity patterns are similar between the two horns and drivers being crossed if you can.

AL K.

[whatever55]

Well folks, It seems the coaxial B&C DCX50 plus the 9KHz Linkwitz-Riley crossover idea that started this thread is already obsolete! With a HUGE thank you to Lee Clinton (Arkytype), we have both horizontal and vertical polar plots of the Faital pro HF200 driver on the Eliptrac 400 prototype horn. It looks like we have what we have all been waiting for, a good two-way Khorn!

Here is the polar plots all overlaid for direct comparison.

I thought it might help to extract the data in a different form to help view what this horn/driver is doing.

I used the fairly standard 6db down point as a reference point to reach these polar angles derived from the published polar graph.

FREQUENCY HORIZONTAL VERTICAL

400hz 100 degree 120 degree (approx)

1250hz 80 degree 80 degree

3150hz 54 degree 44 degree

6300hz 45 degree 25 degree

10000hz 38 degree 26 degree

12500hz 28 degree 16 degree

20000hz 44 degree 40 degree

Basically you have a horn/driver that collaspes it's polars in both the Horizontal and Vertical planes.

mike tn

"Basically you have a horn/driver that collaspes it's polars in both the Horizontal and Vertical planes."

I think that's exactly what you would expect from anything but a constant-directivity horn. It's one of the criteria used to pick the crossover frequency. You pick it where the directivity patterns are similar between the two horns and drivers being crossed if you can.

OK Looks good but does anyone have similar info on ... say the 402 or 510 to do a comparison..... or any idea what they would look like ?

Thanks

[Johnny's Jill]

Basically you have a horn/driver that collaspes it's polars in both the Horizontal and Vertical planes.

mike tn

What is your point? The horns and drivers are JUNK?

The fact of the matter is Dave and ALK provided huge amounts of the data they have on this project, and by doing that they are now venerable all kinds of criticism.

Thanks for pointing out the obvious. Craig!

[Johnny's Jill]

OK Looks good but does anyone have similar info on ... say the 402 or 510 to do a comparison..... or any idea what they would look like ?

I doubt you will find that info readily avaialable, unless done by an independent party. Manufacturers rarely release that much data on their products.

I would like to see that data on the Klipsch 402 and 510 as well.

Craig 73.

[DrWho]

You can't really compare against an orchestra because the stage they're on is technically part of the instrument making the sound we're referring to when we say "orchestra". In other words, when the orchestra is recorded, the ambience of the environment is captured in the recording. We're not trying to create that ambient effect in our listening rooms.

What a bummer, that is exactly what I have been after in a system. Its ability to recreate the environment of the recording. Many of the audio test discs tell you about the recording environment so you can compare how it sounds in your system.

What, then, is it that we are trying to recreate with two speakers?

I think you're misunderstanding. We are not trying to create the recorded environment in our listening rooms, we are trying to re-create it. Therefore the listening room environment will be much different due to the differing goals of reproduction vs production.

Exactly. The recording will already have the big hall acoustics on the disc. The goal of your room should be to make sure that sound gets to your ears and creates that convincing hologram that transforms you to that particular hall. Then if you go to another album recorded somewhere else, then your room should transform you there...instead of having you in the same hall for every recording...

[DrWho]

OK Looks good but does anyone have similar info on ... say the 402 or 510 to do a comparison..... or any idea what they would look like ?

The polar bubble for the K402 is the same shape at every frequency from like 500Hz to ~6kHz...I'm going off memory since it's been a while since I've seen the plots. The K510 has similar behavior, but only down to around 1kHz/2kHz depending on vertical vs horizontal.