Tests: K-69-A driver on Edgar type wood Tractrix horn

[mikebse2a3]

To make things even worse (particulary Horn based systems) treatments such as absorption especially on the side walls at the first reflection points can make this even worse (although imaging in some ways will improve) it will suck the life, dynamics and change the perceived tonal balance of the system in a very negative way while increasing listener fatigue.

Mike tn: Do you attribute this to driver harshness, poor overall balance of the speaker, or something else? I assume that when the front of the room is more reverberent, the effects of speaker/room harsness is diminished (i.e., Toole's comments on room acoustics).

Chris

Hey Chris

The horn speaker in fact can be performing excellent but by applying acoustical treatments in the wrong places can be just as harmfull as they can be helpfull when used correctly.

I believe it is most helpfull to think of how the room is acting throughout the audible frequency range to best understand how a room basically behaves as filters constantly altering the sound reproduced from the loudspeaker as heard/experienced by the listener.

First lets narrow this discussion down to 2channel or 3channel based reproduction of course with well done recordings.

So one extreme example would be to consider a room with no reflections (ie: anechoic chamber). Anyone who has experienced sound played through a loudspeaker in an anechoic chamber knows that this type of enviroment while helpfull for testing loudspeakers is very unfriendly to music reproduction based on 2ch and 3ch reproduction. A normal recording played under such conditions exhibits no real sense of spaciousness and envelopment and simply doesn't have the ability to fool us into believing we are hearing the real performance. We need/depend on the reflections of sound in our rooms to help support the illusion we seek.

If you except the above then we must learn to control/manipulate the reflections so that we can develope this sense of spaciousness and envelopment while also allowing us to localize the images captured/developed by the recording process. So for good localization research shows that early reflections must be controled (ie: absorption, diffusion, redirected, delayed in time..etc....) for the ear/brain to get time to decode the initial cues so that our ear/brain developes a sense of direction, tonality, dynamics, clarity...etc....! Research also supports that we need reflections to arrive at the proper times, sound levels and be in a diffusive state with a well behaved decay rate for music throughout the full frequency range of interest of musical reproduction so that we can develope the illusion of spaciouness/envelopment. The very important lateral reflections I mentioned earlier are a key ingredient to develope this illusion. It's very important that we maintain the proper frequency balance in both the direct and reverbent fields if we want low coloration of the tonal balance of the recording. This last requirement is one very good example of why well controled polar responses from a horn system such as the Jub/K402 is an excellent foundation to build upon from the loudspeaker/room/listener interface for accurate reproduction of our recordings.

The reason I believe absorption (one of the easiest, cheapest and most easily overdone and misapplied treatments IMHO) can be very harmfull under the circumstances I described for sidewall treatment is that due to a horn system's well controlled polars versus loudspeakers with very wide dispersion is that where as the wide dispersion loudspeaker will spray it's sound over a much larger area of the sidewall and thus be less effected by the absorption for the same ratio of wall treatment versus in this example the horn system which concentrates it's energy in a much more narrow and controlled pattern if designed well and thus effected more efficiently by the same ratio of wall treatment. If you place absorption at this reflection point it much more severally alters the later reverbant sound fields frequency balance and decay rate developed from the horn loudspeakers system versus the direct radiator type of loudspeaker which causes very unnatural colorations to be perceived. The absorption basically removes energy like a filter effecting some frequencies more than others thus coloring tonality, effecting dynamics which also results in a loss of perceived clarity and definition of the musical reproduction.

Diffusion when applied properly helps to create,evenout and maintain a proper and well balanced frequency decay rates. If applied properly it can also be used to increase and spread out over time the lateral reflections we so badly need to develope the sense of spaciousness/envelopment to create a very comfortable and low fatigue listening enviroment. Imaging can be perceived more accurately when done properly and all this without a sense of dynamics being lost or an unnatural sense of room deadness being developed as can happen when absortive techniques are misapplied. My experience so far has repeatably shown that properly applied diffusion treatments are less likely to cause negative effects because it redirects the orginally energy in a very beneficial way and helps to maintain the proper decay over a wider frequency range over time versus the tendency of absortion to cause very uneven frequency decay rates over time.

mike tn

[pzannucci]

Wow Mike - the P.Audio PH-4525 looks like a slightly larger K-510 . I think that I'll invest in that one for grins, and try the next smaller one (3223) also since they really aren't pricey (unlike the ones from that I referenced earlier - like 10x the cost). I've already got spare K-69As and an EV Dx38, and just enough test gear to do just about everything that I need to test.

Chris

If you want to play, you might look at the Goldwood horn at Partsexpress. Looks VERY VERY similar to the PH-4525 for $49. Even same dimensions.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=270-204

I have two but don't like the sound of my Selenium D305ti drivers with them. I need to invest in some DMP750s to see how much better they are.

[Chris A]

you might look at the Goldwood horn at Partsexpress.

Thanks Peter,

Yes - I saw the Goldwood horn on Parts Express after I placed my order for the P.Audio PH-4525 horn. Someone on the forum mentioned that the Goldwood horns are from China, whereas the P.Audio horns are obviously from Thailand.

I might invest in one to check its performance/physical characteristics relative to the P.Audio, since it is very low cost.

Chris

[Rudy81]

Here's a question likely to stir the pot. What do you expect to be the sound difference between these fiberglass and plastic horns vs. any of the wooden horns guys are selling? Has anyone done a side by side comparisson? Obviously there is a pretty large price difference.

[Chris A]

What do you expect to be the sound difference between these fiberglass and plastic horns vs. any of the wooden horns guys are selling?

My guess: the difference will mostly be visual only. Wooden horns (of the type that are hogged out from solid or glued blocks) are not cheap, and probably never will be.

PWK talked about the horn materials in his 1948 article that Gil highlighted here recently.I think that wood or wood-like material was used by the early Khorns (the ones that I've seen in Hope). My guess is that cost was a big deal then. So is stability of the material, if you are using thinner sections in order to save on material costs. PWK mentioned that fiberglass sandwich material was the best choice, and it sounded like he had done a lot of trial and error, although it could be that he just performed a trade study. Freedom from ringing, cost, material stability in humid and hot environments, ease of manufacturing complex shapes, available colors, and looks were probably trade study drivers. PWK was a consumate engineer in this respect - he didn't allow esoteric [bs] affect his judgment.

Chris

[Rudy81]

Chris, I was specifically referring to horns like Al's, or Greg's or a few other similar horns which can be purchased after market. There is a large difference in price point, mostly due to labor and perhaps materials. So, I was curious as to any sonic differences, ringing etc. I would guess there must be some difference. For example, Al uses a two layered material with some dampening material in between.

If I get around to messing with the 2" horns, it would be nice to test things with a $100 horn vs. a $250 horn.

I would have guessed someone has run such a comparrison.

[Bigdnfay1]

This is the goldwood horn. I've used Selenium 405,P-audio BM-D750 and now Jbl 2445 with good results. The horn is well built and durable. I use a 3-way setup mainly. Have tried it 2-way and the top end needs alittle EQ. Good horn for the money.

Big D

[Rudy81]

Big D, what driver did you use to attempt two way?

[cjgeraci]

This is the goldwood horn. I've used Selenium 405,P-audio BM-D750 and now Jbl 2445 with good results. The horn is well built and durable. I use a 3-way setup mainly. Have tried it 2-way and the top end needs alittle EQ. Good horn for the money.

Big D

I second Big D's impressions of the Goldwood horn. I currently use the Goldwood horns with my rear pseudo-Belles with Radian 850 drivers, and was surprised at just how smooth they were without any EQ (at least with these 850s - my only point of reference on this horn). I was using them as three-way, but have since been using them as two-way (with the 850s). The horns do sound like they could benefit from a little EQ on the top end when you go two-way, and that is on my "to-do" list when I get caught up with the long honey-do list. That being said, they sound surprisingly good stock in two-way with the 850s, and I am not sweating it for the minute - since they are with my rears.

I may still graduate up to Al or Greg's beautiful Tractrix style horns when the economy improves, but the Goldwoods are a good horn for the money. And well worth it just to get your feet wet in two-inch.

Carl.

[Rudy81]

Thanks Carl. I currently have Al's 1" horns in my Khorns and really like them. My problem now is that I have money invested in those and would like to play around with 2" drivers just for grins now that I have an active crossover. But, buying another set of Al or Greg's horns is not feasible until I sell the first set. Which, I'm not quite ready to do just yet.

[Bigdnfay1]

All three drivers listed above.

[cjgeraci]

Thanks Carl. I currently have Al's 1" horns in my Khorns and really like them. My problem now is that I have money invested in those and would like to play around with 2" drivers just for grins now that I have an active crossover. But, buying another set of Al or Greg's horns is not feasible until I sell the first set. Which, I'm not quite ready to do just yet.

Interesting, Rudy. I am also a big fan of Al's 1 inch horns. In fact, I like them so much that I decided to keep mine until I found something leaps and bounds better. Picking up these inexpensive horns (100 bucks per) was an easy way for me to play around with 2 inch drivers and still keep my Trachorns for the time being (which are up front with 902s).

Carl.

[sootshe]

Thanks Carl.  I currently have Al's 1" horns in my Khorns and really like them.  My problem now is that I have money invested in those and would like to play around with 2" drivers just for grins now that I have an active crossover.  But, buying another set of Al or Greg's horns is not feasible until I sell the first set.  Which, I'm not quite ready to do just yet.

 

Interesting, Rudy.  I am also a big fan of Al's 1 inch horns.  In fact, I like them so much that I decided to keep mine until I found something leaps and bounds better.  Picking up these inexpensive horns (100 bucks per) was an easy way for me to play around with 2 inch drivers and still keep my Trachorns for the time being (which are up front with 902s). 

Carl.

 

Sorry to hi-jack this thread, but can you tell me where you cross the 902's at & what crossover you are using?

[Marvel]

Sorry to hi-jack this thread...

We did that a long time ago, already. [:^)]

[Deang]

Radian rocks. Nice driver choice Carl.

[Rudy81]

We did that a long time ago, already.

At least we are not too far off topic. Still dealing with smaller horns and the K69 and similar drivers. It can always get worse...[6]

[Chris A]

Still dealing with smaller horns and the K69 and similar drivers.

I've been talking about better substitute horns, for less cost. It looked as if the original horn was having trouble with the K-69A (2") driver. [8-)]

[]

[Rudy81]

Still dealing with smaller horns and the K69 and similar drivers.

I've been talking about better substitute horns, for less cost. It looked as if the original horn was having trouble with the K-69A (2") driver.

Chris, I'm with you 100%. A better horn/driver combo for less cost would be perfect. Once issue that keeps causing the most problems is how low do you need the mid to go? You are fortunate to be able to work with a Jubilee bass bin if you ever decided to go with a smaller horn. However, those with a Khorn bass bin have a much more difficult task. I eventually plan on going to a Jubilee bass bin or some bass bin that can go higher than 400Hz satisfactorily. That greatly simplifies driver and horn selection.

[whatever55]

So from what I have read here... the need for EQ is determined by the horn type ? A 402 or 510 you need to EQ any driver, some more, some less. The 2" Tractrix with the proper driver, like a EV DH1A would not need EQ

The only difference would be disspersion. Could someone tell me what those differences would be. Would they show up more in a large room, small room ????

Fire away[li]

[Chris A]

Fire away

...the need for EQ is determined by the horn type ?

Every horn/driver combination is a design compromise. Every horn design will require different EQ for each driver, and all horns/drivers require EQ (whether or not you use it or not in your design).

 

The key phrase is "constant coverage" (a coined phrase) meaning that the frequency balance of the horn/driver vs. frequency and off-axis angle is as invariant as can be designed, right up to the design limit of the horn/driver in azimuth and elevation (to control ceiling/floor/side-wall bounce).

The idea that you are going to get "flat response" out of a horn/driver/cabinet combination effectively implies that you are talking only about on-axis measurement only.

As Floyd Toole, former VP Engineering of JBL/Harman, says - "speakers that have good off-axis performance (i.e., balanced output off-axis) are consistently preferred by listeners over those that do not have good off-axis performance." What kind of speakers have poor off-axis performance? Dipole radiators like MartinLogans, Magneplanars, and even Linkwitz's own speaker designs(dipoles).

(Boy, I've done it now... [:#] )

Chris

Edited October 26, 2015 by Chris A