Driver Comparison for the K 402 Horn

[Panacea Engineering]

This thread will be about MY comparison of various drivers for the K 402 Horn. The comparison will be to a Martinelli Wooden 20” Horn with a Beyma CP 750ND 2” Driver with a Two Way Passive Crossover crossed at 750 Hz.

For the 402 Horn, we will be using the Beyma CP 750ND, Tad 4002 and JBL 2482 Drivers, all of which are 2” and the frequency range runs from 500 Hz up to 20K Hz.

One of the biggest issues that I am aware of, when it comes to mating horn/horns to a base bin is the question of time alignment. I am hoping someone can answer the following question in laymen’s terms so we ALL can understand. Please feel free to advise, correct or suggest anything that I may have stated wrong as this is a total learning experience for me and hopefully a few others on the Forums.

QUESTION: In a typical recording session of an Orchestra, the microphones (in a two channel recording) are normally placed left and right of the Conductor’s Podium. I know that in reality, most recording sessions have multiple microphones placed al over the place, but a normal two channel recording is what you ultimately hear reproduced. The Orchestra is normally situated with the higher frequency instruments to the front with the tones getting lower going back to the percussion on the rear of the Orchestra. Normally First Violin is stage left (Facing the Orchestra) about 12 feet from the Conductor and could be within eight to ten feet of the left mic. The Chimes and normally the Tympani’s (sp) and Drum section are just left of stage center and could be as much as 100 feet from the Conductor. How can time alignment possibly have any affect on anything, when the lower bass notes have to travel 80 to 100 feet to get to the same location of First Violin and the microphone? THAT is the burning question that I have and I hope someone can answer it to where I can understand the alignment theory. The listener in the audience can be anywhere from 15 feet to 200 feet from the entire Orchestra with all of the sounds traveling vastly different paths to get there. Again, HOW can time alignment have anything to do with the final reproduction through the speaker when it was messed up way before it got to the microphone?

We will start the testing next week as the TAD’s are on the way from California and should be here next Wednesday. I am hoping that this thread can answer some questions that we all have and be informative.

Thanks,

W. C.

[Don Richard]

Again, HOW can time alignment have anything to do with the final reproduction through the speaker when it was messed up way before it got to the microphone?

Because the temporal errors caused by the loudspeaker system will interfere with the accurate reproduction of the sound field captured by the microphones. Time alignment issues within a loudspeaker system cause comb filters and polar lobing which affect frequency response, transient response and imaging qualities. Timing differences picked up by the mics help to define where a certain sound appears to be placed within the recorded sound field, similar to the way the human psychoacoustic system defines the location of a point source of a sound. Think production vs reproduction.

[ClaudeJ1]

Think production vs reproduction.

Excellent response, Don.. I'm in full agreement with your succinct definitions here. Bravo.

[ClaudeJ1]

We will start the testing next week as the TAD’s are on the way from California and should be here next Wednesday. I am hoping that this thread can answer some questions that we all have and be informative.

I'm hoping you will go with the active Xover route instead of passive. Even without official "Roy" settings on your 402's, you can spend less than $300 on a Behringer DCX 2496 and twiddle the knobs to your heart's content. This will allow you to create custom setting for every driver and save them via the front panel. You can just use the same methods we used while I was at your place as long as you have a precise and NON Movable mike location at your listening spot. Set it up in the left corner, EQ the bass reasonably flat from 50-500with a Linkwitz-Riley 24 or 48 db/octave slope (48 preferred). Save those setting and don't touch them. Now the only variable will be the the drivers on the exact same horn, which whose face is in the same plane as the front of the Golden Jube.

By superimposing the K402 cruves, you should be able to EQ each driver pretty close to each other. Now any audible REMAINING sonic differnces can be attributed to the drivers themselves and their resonances, etc.

While I really liked your Martinelli horn, with 800 Hz. passive network on the Golden Jube, I still think the TAD/402 will win because: 1) Berrylium will give your the bes "micro detail" at all frequencies, 2) the K402 has superior frequency response and pattern control down to about 580 Hz. 3) Even though you wont be using it, the K402 works down to 300 Hz. and below with drivers that work in the lower range. 4) Last but not least, you will be taking the 500-800 Hz. band out of the Golden Jube and into the K402 horn, which will give your SUPERIOR transient response and lower distortion.

[CIGARBUM]

I don't know if it makes any difference but I believe the JBL 2482 goes down to 300.

Cigarbum

[Panacea Engineering]

Don,

ABSOLUTELY a GREAT responde.....! Hell....even I can understand that. It just seems like two feet would not make any audible difference to "perceived" sound, as fast as it travels......

[Guest " "]

Again, HOW can time alignment have anything to do with the final reproduction through the speaker when it was messed up way before it got to the microphone?

it's not....this

[Guest " "]

is represented by this.....which is captured with 16 mic's and mixed into 8 to 16 tracks and made available for 2 channel, prologic 3 channel, 5.1 DTS, 7 channel, etc. In the future....a 16.1 music system will probally represent drivers optimized to reproduce specific instrument by position clusters and those 16 drivers would probally need to be positioned as the mic's are in this map. end of all alignment issues...pure analog....no Digital hanky panky.

[Marvel]

Many recordings of orchestral music still use the Decca tree, which only uses three microphones. It is also suspended higher overhead, which lessens the distance of instruments in the back compared to those in the front.

Bruce

[djk]

The Denon classical recordings have delay lines on the spot mics and the rear mics to align them with the two main mics.

Sheffield Labs really blew it when they added spot mics on the drum kit (without delay) on The King James Version.

[Chris A]

QUESTION: ...How can time alignment possibly have any effect on anything, when the lower bass notes have to travel 80 to 100 feet to get to the same location of first violin and the microphone? THAT is the burning question that I have and I hope someone can answer it to where I can understand the alignment theory...Again, HOW can time alignment have anything to do with the final reproduction through the speaker when it was messed up way before it got to the microphone?

Sound stage width and height, in addition to reproduction presence, is what you'd be missing in addition to crisp percussion strikes. Once you've heard time-alignment in A-B with incorrectly aligned speakers, you'll not soon forget the experience.

When you get to small groups such as jazz, blues, smaller classical ensembles,and folk groups, the effects of small time delay differences can be heard clearly, especially with sounds that are impulsive like drum sets and other percussion. Some of the most demanding recordings that I have is of percussion ensembles with string orchestra accompaniment. Others include violin and pianoforte concerto and solo instrument recordings.

Nothing other than time alignment of drivers/horns can remedy the effects of misalignment. If you listen to a full-range driver system, you'll also hear the effects of time alignment except that in this case you'll also have to endure significant amounts of FM and AM distortion during musical peaks, reproduction of bass with hfs, and louder passages to hear the time-alignment effects.

Chris

[ClaudeJ1]

I don't know if it makes any difference but I believe the JBL 2482 goes down to 300.

Cigarbum

Yes, it's a very RUGGED driver, but it's limited by mass to about 4K on the top end, so you MUST go with 3-way.........although my 1133's go down to 300 Hz to 5Khz. and I must go 3-way with them (the K1132's are designed for two way with shelving EQ 500 to 16K). I still think titanium or aluminum sound better by way of transient response (lower mass) than the Phenolic drivers like the JBL 2482..............of course, Beryllium beats them all, but again, you are always trading off the low end for the high end.

[ClaudeJ1]

I don't know if it makes any difference but I believe the JBL 2482 goes down to 300.

Cigarbum

Yes, it's a very RUGGED driver, but it's limited by mass to about 4K on the top end, so you MUST go with 3-way.........although my 1133's go down to 300 Hz to 5Khz. and I must go 3-way with them (the K1132's are designed for two way with shelving EQ 500 to 16K). I still think titanium or aluminum sound better by way of transient response (lower mass) than the Phenolic drivers like the JBL 2482..............of course, Beryllium beats them all, but again, you are always trading off the low end for the high end.

[ClaudeJ1]

Nothing other than time alignment of drivers/horns can remedy the effects of misalignment. If you listen to a full-range driver system, you'll also hear the effects of time alignment except that in this case you'll also have to endure significant amounts of FM and AM distortion during musical peaks, reproduction of bass with hfs, and louder passages to hear the time-alignment effects.

This sure makes a good argument for Danley's Synergy horns, which can do square waves from 250-2,500 Hz.

[ClaudeJ1]

Don,

ABSOLUTELY a GREAT responde.....! Hell....even I can understand that. It just seems like two feet would not make any audible difference to "perceived" sound, as fast as it travels......

When I asked Bob Moers, former Klipsch President, and PWK himself, about 8 years later, they both said that 2 milliseconds was inaudible on speech and music with loudspeakers, but it would be detected with headphones and clicks.

My question would be.............which speakers? and Were they time aligned? In what room?

[Chris A]

When I asked Bob Moers, former Klipsch President, and PWK himself, about 8 years later, they both said that 2 milliseconds was inaudible on speech and music with loudspeakers, but it would be detected with headphones and clicks.

This is a well documented effect. If PWK said this, I believe that he wasn't telling the whole truth on the perceived effect of delays. See the top of page 4 of this article.

Chris

[Panacea Engineering]

Chris,

Help me: Isn't page four talking about Time Delay (TD) in a sweep from Left to Right between the speakers, causing the sound to shift to the Left? I contend that you can not discern the TD on a horizontal plane coming at you from the Left and Right (time Aligned) Chanel to the center listening position. Two feet is 1.8 ms and I really doubt that you could pick that up audibly. I could certainly be wrong but what you are saying IS: the K Horns I have been listening to for close to forty years is CRAP......and I just find that terribly hard to believe...! I certainly know all about delays as it relates to production work as I have been involved in that most of my career but I truly do not believe that I have been listening to garbage through my systems over a couple of milliseconds in horizontal delay. If you move the Chellos back two feet on the stage, are you going to tall me that you could notice that from the audience position? I am truly here to learn, but I don't want to be "Hog Washed" either. Can you really tell the difference between a Coat Hanger and super cooled Nitrogen filled speaker wire? I sometimes think Perception gets the best of ALL of us when it comes to audio and what we THINK WE hear.....I digress as I did not want this to become a Time Delay War........Some believe in it....Some don't...Can we just leave it at that?

[Panacea Engineering]

Additionally: I am pretty sure that we are going to be able to acquire a DX-38 for testing of the K 402 with various drivers. I have ALL of the files necessary to program it, INCLUDING delays, etc. I want ALL of you to know THAT I will be the first to admit;

One: If it sounds better

Two: If I feel the time delays made any appreciable difference, what so ever.

We are going to test actively and also passively. This test is for MY ears and NO one else’s so again in any situation like this: YMMV I will certainly freely admit if I am wrong about anything, as I am pretty used to eating Crow Pie.....

I wanted to do these test to satisfy, in MY own mind, that the K 402 sounds better to ME than the Martinelli Horns….That’s ALL Folk’s…..?

[Chris A]

W.C.,

I'm not trying to break any bubbles here, so if this challenges your perceptions of "goodness" of loudspeakers, then let me just say that I'm not trying to put anyone into the argument. I'm referring to measured, repeatable effects using humans, including myself as guinea pig. YMMV.

I wish that the situation was as linear and as evident and simple as you describe above (it isn't), but my ears tell me that there are some significant issues with as little as 1/5 wavelength difference at the crossover frequency band. djk (Dennis) and Marvel also note this effect using a movable tweeter on top of a La Scala or other speaker type going into and out of "focus" within a 3/8" movement at the crossover frequency band of ~6 KHz: I've heard this too with my Belle at home using my Dx38 to step through +/- 1/2 inch equivalent change in correction for the tweeter to midrange. The difference was enough for me to retain the center Belle between my Jubs, otherwise, it wasn't going to stay. Note that I'm tri-amping my center Belle with good timbre matching with my Jubs now, but not before time alignment occurred. In fact, the Belle didnt sound very good at all before the second Dx38 active crossover was effectively applied in tri-amping (the other Dx38 crosses my Jubs at 400-450 Hz).

An equivalent 1/5 wavelength rule of thumb at 450 Hz would yield about a +/-1 1/4 inch equivalent alignment accuracy between K-402/TAD TD-4002 driver crossover alignment with the Jub bass bin. I have also done this experiment using my Dx38 as the "displacer", and the results are both audible and significant enough for me to spend time getting it set right. By the way--this easy to correct once you get close to the right time alignment settings using the right equipment. You simply cannot do this correction using a passive analog crossover: sorry.

I once had my high school band director tell me that we, as humans, tend to become acclimatized to the level of music output that we've been continuously subjected to, and become insensitive to certain performance issues. Once we hear professional musical performance, we instantly know the difference, however, and we come back to the junior high or high school performance with new ears.

Chris

[Guest " "]

I wanted to do these test to satisfy, in MY own mind, that the K 402 sounds better to ME than the Martinelli Horns

is this going to be problematic.....if you have "authorized klipsch dealer" in your signature block....... is it really a good practice to say this non-klipsch thing is better than this klipsch thing. Based on what I know about the things you like to "start", I would not be surprised if "authorized klipsch dealer" comes off your sig line.