Hybrid Trachorn

[mikebse2a3]

Great Post Dean!

Great Visual and explanation! which shows one of the reasons why the K402 (for those who believe in the importance of flat on and off axis frequency response with controlled directivity over it's designed bandwidth) is an awesome horn that IMHO is at the cutting edge of horn technology available today.

mike tn

[mikebse2a3]

Examing why people think and say what they do, and attempting to find ways to better explain the complex mechanisms involved with all this stuff, isn't "slamming". Challenging ideas and comments that aren't accurate -- isn't "slamming" either

Again thanks for stepping in and saying this Dean in such a clear way!

mike tn

[Deang]

Forums don't really seem to be conducive to this kind of discussion. So much of a person's intent is wrapped in facial expressions, body language, and tone of voice -- all of which are absent when writing. I'm by nature somewhat cynical and sarcastic, but not usually in a mean-spirited way -- but it sure doesn't come off that way when I post! Threads usually get out of hand because of simple misunderstanding.

[seti]

I like horns.

[PrestonTom]

OK....

Has anyone built a Trachorn that would replace a 402 ? Does anyone have a drawing or dimensions for such a horn with a recommended driver ?

What improvement over a 402.69 combination would one expect ?

Prettier ?? less EQ required ? simpler network ??

This thread has ceased being educational, but you asked a legitimate question so let me try to be helpful.

This would be an apples vs oranges comparison.

1. K-402 is a CD horn (see previous posts) while the trachorn is not (probably is not, since we have not yet seen the polar responses).

2. The K-402 is a 2 inch throat while the trachorn is (probably) a 1.4 inch throat (correct me if I am wrong). One consequence of this is that it might be more prone to distorting if the crossover is set too low or without a sufficiently steep filter. There would be other differences also.

3. Again, folks are getting confused about whether EQ is required by design (i.e., when using a CD horn) or by necessity (the horn/driver is somehow bad and needs to be "fixed").

4. Regarding the issue of using a CD horn: It is not simply (as some suggested) a requirement for someone listening "off-axis". There is more to it than that. The heart of the issue regards the power response (which Dr Who parenthetically mentioned but did not explain).

5. The k-402 is substantially larger than the trachorn. One consequence is that is will control (think of it as focusing) the sound more tightly in the horizontal and vertical dimensions). It is not clear how much better this is done relative to the trachorn since we have not seen the polar responses or directivity index) of the trachorn. The physical consequence is that the degree of interaction between the horn and the room will differ. As always, whether this perceptually important to the listener is in the eye of the beholder.

Again it is in the eye of the beholder whether the criteria of CD (and its effect on power response), directivity index (control of the dispersion) and distortion are important attributes that a system should be designed around. Please, please, please, do get caught up on this issue that EQ is inherently bad.

I only responded because you asked a legitimate question. I have tried to limit myself to fairly factual and non-controversial statements because I do not feel like arguing when the tone of the discussion has descended to this point.

Good Luck,

-Tom

[Marvel]

Dean - what are you listening to now? I hadn't realized you got rid of your Jubs.

Tom - It's still educational... Things will cool down a bit and there can be more progress in this thread. Although I have understood the concepts shown in the pic Dean posted, it is great to see it visually displayed.

The Trachorn, as designed by Al and built by Martinelli, is for a one inch throat driver. It could easily be designed and made for a two inch. I am plotting out a tractrix horn to use a five inch or 6.5 inch speaker, to be used for upper bass. I want to try to couple that to the MWM cabinets I am building.

Bruce

[Deang]

Has anyone built a Trachorn that would replace a 402?

A "Trachorn" is Al Klappenburger's replacement for the K-400 or K-401 for the Klipschorn. It is built by Bill Martinelli and has a 1" throat. It is designed to be used with a K-55 (with adapter), the popular Altec 902, or any other 1" driver. It is not a Constant Directivity horn, and is designed for use in a three-way system. Al does not sell a 2" version, though there has a been a handful of DIY efforts. If one was so inclined, they could use Al's Trachorn with a 1" driver and tweeter of choice with the Jubilee LF section. Network design is significantly simplified if going three-way. Whether this is an improvement in sound or not is completely subjective, though from the technical perspective -- it's not.

[PrestonTom]

Dean: Thanks for clarifying things.

Well, it is looking like these two are very, very different critters.

[Islander]

So is the 510 horn a miniature 402 in almost every way, or are there significant differences other than size between those two Jubilee HF horns?

[DrWho]

A horn that "works on its own" is collapsing the
vertical response and as the driver climbs in frequency it begins to
beam. In this case, the horn is providing the EQ (to lift the natural
falling response of the driver), but at the expense of an uneven power
response. Extensive studies have shown that loudspeakers with an even
power response (equal amounts of on and off-axis energy) are preferred
by listeners over those where the high frequencies have narrowing
dispersion (beam). The only advantage with that kind of horn is that
you need less parts in the filter (cheaper to build). So, going from
that kind of horn (K-400) to another of the same type (K-403, etc.),
isn't really an "advancement". Though it requires more network, a CD
type horn is an advancement because it produces the correct balance
between on and off-axis energy. DSP allows for fine-tuning of the
correction, but its use isn't mandatory.

I just wanted
to add one thing...the amount of energy being unloaded into the room is
(ideally) the same for a horn that collapses polars and a horn that
doesn't (when neither is using EQ). It's just that the non-collapsing
horn is spreading that energy out over a wider area. I don't think this
behavior is terribly apparent in the graphs since the second graph is
showing the behavior after electrical compensation. It takes a crap
load more power to maintain a constant intensity over wide polars than
it does to only have a flat intensity on a single axis.

I also
wanted to add that speakers don't have a flat efficiency. Amplifiers
are pushing out a constant voltage, but the impedance of the speaker is
different at different frequencies...so depending on the impedance at a
particular frequency, the power is going to be different (V^2 / R).
Anyways, the impedance of most every driver in the world rises as you
go higher in frequency, which means there is naturally less power being
put into the driver at higher frequencies. So electrically boosting the
highs is a lot smaller compromise than it might otherwise appear to be.

And
lastly, I wanted to add that PWK claims that 90% of the energy we hear
at the listening position is a result of the indirect sound bouncing
around the room. The Dope From Hope article talking about this is on my
laptop which is dead, otherwise I'd post it. With a collapsing polar
horn, that means 90% of your
sound has about a 20dB tonal imbalance (more lows than highs). In my
mind, that's a pretty big sacrifice for obtaining a perfect tonal
balance for only 10% of the sound. The thing I find most interesting
about this is that when dialing in a system like this by ear, you'll
usually end up with boosted on-axis highs and attenuated on-axis lows.
Essentially, the system tuned by ear will naturally be tipped towards a
flatter
power response, but it will never get to the point of a perfectly flat
power response because our ears put some extra weighting onto the 10%
of sound that arrives sooner than the reflected sounds. The end result
is that things will always sound a little bit off and you'll feel the
need to tweak things slightly from song to song. I think this is much
along the lines of what sfogg was describing in his configuration.

Also, the "power response of the room" (for lack of a better
description) is rarely going to be flat...so if your room is live at
the higher frequencies, then you may actually want less highs in the
off-axis response of the horn (implying the collapsing might be a good
thing). However, I would argue that a room with a nonflat power
response is a non ideal room, so it really should not be the role of
the speaker to compensate for that in the ideal world. The implication
here is that a bad room will make a properly operating speaker sound
nasty as all get out. Think about it, if a speaker with a 20dB tonal
imbalance sounds right, then chances are there are other factors
compensating for that. So if you don't change the compensation when you throw
in a speaker without
a 20dB tonal imbalance, then the synergy of the
system is now off by 20dB. 20dB is a lot - heck, 1dB is a lot when
you're talking wide bandwidths. If fixing the room is not an option,
then mangling the power
response of your speaker may be a best option...although I would argue
that a higher level of fidelity could be obtained if someone were to
figure out exactly what power response was needed from the speaker in
order to achieve a proper tonal balance in the indirect sound while
maintaining a flat response on-axis.

The latter is kinda where I'd like to see the DIY Trachorns going
since DIY is going to be the only way that a horn can be custom
tailored for a single aesthetics/budget limited listening environment. Maybe 10, 20 years down
the road there will be a free tool that can provide some level of
predicting polar responses and then people can get more involved with
tailoring a speaker to an imperfect room. Heck, you could tailor the
power response to be whatever you want - say you find that you prefer things tipped
one way or another. This is where a lot of the art (fun stuff) comes into play.

The K402 is just the first tractrix horn I know of that maintains a
mostly flat power response without the compromise of diffraction slots.

[DrWho]

So is the 510 horn a miniature 402 in almost
every way, or are there significant differences other than size between
those two Jubilee HF horns?

As I understand it, the K510 is the same design as the K402, except that it doesn't control its polars to as low of a frequency.

I
think the K402 controls polars down to around 500Hz and the K510 only
controls down to 1.5kHz or so. It's basically just a function of the size of the mouth. Below those frequencies, the polar
response starts to move towards omnidirectional - so you begin to have a
lot more of the sounding wrapping around the back of the speaker.

It's a lot easier to see by looking at the measurements, but I don't have them readily available.

[greg928gts]

You're right mike tn, I don't really know you, but I do know that every time I've got something to say about Jubilees, you ignore the good things I have to say and reply with a long post of blue words that are just not that interesting to me. In the past, I've tried ignoring you, but you just keep coming at me with a condescending tone.

That's your perception Greg which I obviously can't change but thats not in the least what I have been trying to do.

Your right this is an open forum and my responses have been based on statements you have posted based on your opinions which I find different from my own and I have responded (thats what happens on a forum you know) to them with reasons why I believe your thinking is in error. This challenging of ideas is one way that we can expand our understanding of things and if taken in that light this is good for all and I'm sorry you haven't understood this is what I started out trying to do with you. The only one making it personel is you Greg and my offer to try to help earlier was genuine and as far as the condescending tone you got what you gave at those times.

Of course, I'm not going to ask you to stop the long replies about my Jubilee posts, I wouldn't do that, this is an open forum. But please don't expect me to play along nicely.

Yes Greg I will respond to your post in any way I feel is appropriate based on what you have posted because it is an open forum. If you don't like someone giving a response challenging those ideas with hopefully good reasoned thoughts and facts then we don't have a forum anymore do we.

My responses were not attacks but instead attempts at reason but when you slam someone then don't be surprised or act innocent when they respond likewise.

mike tn

I direct your attention to the second post down on page 8. I didn't ask for that.

Whatever mike tn, you're the type of person who's always going to get the last blue word in.

Greg

[PrestonTom]

Dr Who, thanks for wrapping that up. You are becoming remarkably lucid in your old age.

[Coytee]

Sometimes I don't know what drops down faster.....

1. These threads

2. The stock market

3. Bill Clintons pants

[:#]

[Guest David H]

How come you Jub guys didn't teach me the secret handshake?

Dean, from what I have observed of the secret handshake goes as follows: Its a left handed shake thum over forefinger and then a right hook to the grill. Yeah it kinda sucks but what are you going to do.

[Coytee]

Say Greg, did you get my email about the passive?

It's a bonafide offer if you're interested

(I offered to send him Dean's old passives to try out)

[greg928gts]

A horn that "works on its own" is collapsing the vertical response and as the driver climbs in frequency it begins to beam. In this case, the horn is providing the EQ (to lift the natural falling response of the driver), but at the expense of an uneven power response. Extensive studies have shown that loudspeakers with an even power response (equal amounts of on and off-axis energy) are preferred by listeners over those where the high frequencies have narrowing dispersion (beam). The only advantage with that kind of horn is that you need less parts in the filter (cheaper to build). So, going from that kind of horn (K-400) to another of the same type (K-403, etc.), isn't really an "advancement". Though it requires more network, a CD type horn is an advancement because it produces the correct balance between on and off-axis energy. DSP allows for fine-tuning of the correction, but its use isn't mandatory.

This is very well explained Dean, and I get it. I got it before, maybe not as clearly as I get it now.

I agree that the soundbite type quotes that I lay on the Jub crowd can be irritating. Some of that is reactionary.

I would like to try the passive approach. I believe it will make a huge difference in my system, mainly because I will be able to simplify the system to a great extent. Still a lot of components in the passives. Kinda reminds me of the ALK ES networks that underwhelmed me. The reason I haven't done it is because of cost and the risk of not liking them and then not being able to resell them. Just doesn't seem worth the effort to me. I'd rather spend my time and money on building my own mid horns, that just seems more in line with what I want.

I still think in the end, I'd prefer a horn speaker system doing its thing all on its own, naturally. PLUS, I'd like to have these speakers in my living room. Cripes, I just can't get those 402's past the front door without being asked how long they're going to be in there. Grill cloth won't do it, veneer won't do it. (WAF for those not married)

LOL on the "studies have shown". That's like polls. What would happen if you assembled a bunch of stereo geeks in a room and played the same song through the same system twice, only the second time you equalized the signal by adding a little more bass and a little more highs? I bet most would prefer the equalized version.

Greg

[greg928gts]

How come you Jub guys didn't teach me the secret handshake?

Because you sold your Jubs.

Greg

[greg928gts]

Say Greg, did you get my email about the passive?

It's a bonafide offer if you're interested

(I offered to send him Dean's old passives to try out)

Yes, I replied last night, you didn't get it?

I really appreciate the offer. This will give me an opportunity to try passives at a very low cost.

Greg

[Coytee]

Yes, I replied last night, you didn't get it?

I really appreciate the offer. This will give me an opportunity to try passives at a very low cost.

I've not seen it. I'll go look again. I just got a new email address so I don't know what the system sent you. You can sent to ralbrigh@bellsouth.net that's the "old" one that will be dead in a couple weeks BUT, I know it works.

I'll presume the flavor of your response above to indicate interest in trying them.

Boxes are "already" (as in still) in my car so I can get them going out either Monday/Wednesday/Friday. I can't ship out on Tuesday/Thursday as we've got some seminars going on.

Dean... I'm going to send him your passives to try out. Anything he might need to know that I'm unaware of?