The thing about horns and waveguides is that they can be complex and sometimes I bet things don't line up how I think they should but generally speaking
We should find the same trend on this horn. When applying the approach, crossing 2x (or more apparently) above cut off...This, is the area that I would consider to base that point from....Group Delay is likely is peaking here, as well as Decay....
Here being the Highlighted area on the picture above....
This horn, based on these ideas, is only good from 800hz apparently.......Emphasis on "based on these ideas" because I said above, Horns and the different expansion rates, and design approaches can cause complex results that may veer from how I've seen things go with tractrix and jmlc....So an analysis of measurements would be the right thing to do before throwing the book at this horn. I am trying to reverse engineer the ideas from the electrical impedance....If you own the horn there is no need to reverse engineer, just read the measurements lol. Marks approach nulls the parts that he cared about...Group Delay....
I trust Marks ears....I don't trust the "cutoff" that manufacturers tell their customers lol....My guess is that this horn is the biggest horn in his arsenal at least applied to his experience of going "low" with compression drivers....and his "Big" horn is only faithfully loading, in my description of desired performance, down to 400hz lol, to which I would want a crossover closer to 600hz-800hz according to theory I've applied here. Mark said he didn't like it crossed low....think about it. Mark correct me where I have assumed incorrectly about your experience with big horns and compression drivers crossed low...but in regards to the Me646 Horn. I am assuming that the trend is holding true, to allow me to reverse engineer these thoughts, by means of electrical impedance and this horn is best crossed much higher than 300hz... Or better said... This horn is not suitable for playback down to 300hz.
We should find the same trend on this horn. When applying the approach, crossing 2x (or more apparently) above cut off...This, is the area that I would consider to base that point from....Group Delay is likely is peaking here, as well as Decay....
Here being the Highlighted area on the picture above....
This horn, based on these ideas, is only good from 800hz apparently.......Emphasis on "based on these ideas" because I said above, Horns and the different expansion rates, and design approaches can cause complex results that may veer from how I've seen things go with tractrix and jmlc....So an analysis of measurements would be the right thing to do before throwing the book at this horn. I am trying to reverse engineer the ideas from the electrical impedance....If you own the horn there is no need to reverse engineer, just read the measurements lol. Marks approach nulls the parts that he cared about...Group Delay....
I trust Marks ears....I don't trust the "cutoff" that manufacturers tell their customers lol....My guess is that this horn is the biggest horn in his arsenal at least applied to his experience of going "low" with compression drivers....and his "Big" horn is only faithfully loading, in my description of desired performance, down to 400hz lol, to which I would want a crossover closer to 600hz-800hz according to theory I've applied here. Mark said he didn't like it crossed low....think about it. Mark correct me where I have assumed incorrectly about your experience with big horns and compression drivers crossed low...but in regards to the Me646 Horn. I am assuming that the trend is holding true, to allow me to reverse engineer these thoughts, by means of electrical impedance and this horn is best crossed much higher than 300hz... Or better said... This horn is not suitable for playback down to 300hz.
Attachments
Last edited:
There's a bunch of correlating data, hard to say "I can't explain it" after all of that.
Stop being so touchy. I have presented evidence to support a theory
Until I know for sure, its just a theory.
Correct me where you see fit. I am searching for correction!
These and all horns operate within the same physics....I can do a run down of a Bass Reflex or Transmission line and show the same trends....Maybe those aren't designed right either?
I'm really interested in seeing how these aspects that I've criticized play out on a Horn designed "properly" whatever that means. I can only do tractrix and jmlc for the most part.
All horns have resonance.....
Last edited:
If I am wrong, it won't be the first time. There are plenty here with knowledge of horns and simulation. I'd love to see some data, not opinion, but measurements, simulated or real, that do not follow the trends that I have shown in the last sets of posts, regarding loading horns. Especially something that isn't an estranged profile like conical. Practical might be the word...or Current...But Hey if you wonna show what conical does its all educational
And not bits and pieces either omggggg
Acoustic Impedance
Electrical Impedance
Excursion
Spectral/Burst Decay
Group Delay
Throat pressure
And not bits and pieces either omggggg
Acoustic Impedance
Electrical Impedance
Excursion
Spectral/Burst Decay
Group Delay
Throat pressure
Last edited:
Perhaps your perceptions of what is happening here, isn't really happening here.
It would be great if you try and learn from your missteps in "playful" Communication.
Measurements and simulations need to be understood and interpreted correctly. I tried to help you see what they were showing but you didn't want to hear it.
You misread just about everything, and insisted that horn science conform to to 'camplo'.
This board has been entertaining and informative. Now, it's becoming sad.
This board has been entertaining and informative. Now, it's becoming sad.
Last edited:
Are you being literal or metaphorical lol, I think the latter, as in the big horn will come with some adverse side effect. In this case the cons are, larger center to center spacing and smaller sweet spot. I also think the lower tuning note carries a higher degree of excess decay/group delay
Last edited:
You arent being specific and you exaggerate.
Im really hungry for some objective data, not opinion.
I just recently provided an objective theory and still await for some data to prove me wrong...I never said "I cant be wrong"....and you arent showing the opposing data either so what are you doing?
Last edited:
I dont recall ever saying the horn does not have any loading at 300hz. "Loading too" is another statement used vaguely...to what degree of load....not all load is created equal.
I said what I said about peak resonance, group delay, decay, and if Mark chooses to expose the group delay and it lands where I predicted then what? I described a method of choosing desirable bandwidth, and if the measurements concur then what?
I said
And then you say
Thats not even opposing anything I said lol, stop playing around guys!
Last edited:
Really....
https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf
For the record I have not claimed to call this point I designated in the hornresp graphs a "cutoff" =)
Last edited:
The story continues (document camplo linked #8234) and defines what cutoff is.
"
If you apply this concept to the
conical and exponential horns by
looking at how the wave-fronts
expand in these two horns, you
will see why the cutoff phenomenon occurs in the exponential
horn. You must consider the flare
rate of the horn, which is defined
as (rate of change of wave-front
area with distance)/(wave-front
area).
In a conical horn, the flare rate
changes throughout the horn,
and the point where propagation
changes from reactive to resistive
changes with frequency throughout the horn.
In an exponential horn, the
flare rate is constant. Here the
transition from reactive to resistive wave propagation happens at
the same frequency throughout
the entire horn. This is the cutoff
frequency. There is no gradual
transition, no frequency dependent change in propagation type,
and that’s why the change is so
abrupt.
"
So it seems cutoff is a property of exponential (and hyperbolic) horn, if you use exponential horn you have a cutoff. Use some other type and there is no cutoff, according to the text.
Seems to be nice document explaining all kinds of horn related stuff. I suppose it is reliable source, but need to be careful copy pasting here since the info is scattered through out. Here is another one relevant on the debate
"
The throat impedance of an exponential
horn is shown in Fig. 2. Above the cutoff frequency, the throat resistance rises
quickly, and the horn starts to load the
driver at a much lower frequency than
the corresponding conical horn. In the
case shown, the exponential horn throat
resistance reaches 80% of its final value
at 270Hz, while the conical horn reaches
the same value at about 1200Hz.
An infinite horn will not transmit
anything below cutoff, but it’s a different
matter with a finite horn, as you will see
later.
"
...
"
Finite horns will transmit
sound below their cutoff frequency. This can be explained as
follows: the horn is an acoustical transformer, transforming the
high impedance at the throat to
a low impedance at the mouth.
But this applies only above cutoff.
Below cutoff there is no transformer action, and the horn only
adds a mass reactance.
An infinite exponential horn
can be viewed as a finite exponential horn terminated by an infinite
one with the same cutoff. As you
have seen, the throat resistance
of an infinite exponential horn is
zero below cutoff, and the throat
resistance of the finite horn will
thus be zero. But if the impedance present at the mouth has a
non-zero resistance below cutoff,
a resistance will be present at the
throat.
"
So, when ever talking about cutoff there should be mention of exponential (or hyperbolic, or what ever in question) horn to avoid confusion what the cutoff is.
Here is interesting nugget:
...
"
Another factor you need to
consider is the termination at the
throat. If there is a mismatch between the driver and the horn,
the reflected waves traveling from
the mouth will again be reflected
when they reach the throat, producing standing waves in the
horn.
"
Mark100 has posted several times he didn't find any issue with square throat adapter (conical MEH). The quote reads throat mismatch is not a problem if there is no mouth reflection. There is long section in the text handling optimal mouth size of exponential horn and at the end of it says that big conical horns shouldn't have much mouth reflection. Observation from measurements fit the text nicely, at least in my mind. 🙂
..
"
These considerations are valid for
exponential horns. What, then, about
hyperbolic and conical horns?
Hyperbolic horns with T < 1
will approximate the exponential
horn expansion a certain distance
from the throat, and the mouth
termination conditions will be
similar to those for an exponential horn. Conical horns show
no sign of having an optimum
mouth size. As length and mouth
size increase, simulations show
that the throat impedance ripple
steadily decreases, and the horn
approaches the characteristics of
an infinite horn.
"
..
Anyway, fun compact paper on horns.
"
If you apply this concept to the
conical and exponential horns by
looking at how the wave-fronts
expand in these two horns, you
will see why the cutoff phenomenon occurs in the exponential
horn. You must consider the flare
rate of the horn, which is defined
as (rate of change of wave-front
area with distance)/(wave-front
area).
In a conical horn, the flare rate
changes throughout the horn,
and the point where propagation
changes from reactive to resistive
changes with frequency throughout the horn.
In an exponential horn, the
flare rate is constant. Here the
transition from reactive to resistive wave propagation happens at
the same frequency throughout
the entire horn. This is the cutoff
frequency. There is no gradual
transition, no frequency dependent change in propagation type,
and that’s why the change is so
abrupt.
"
So it seems cutoff is a property of exponential (and hyperbolic) horn, if you use exponential horn you have a cutoff. Use some other type and there is no cutoff, according to the text.
Seems to be nice document explaining all kinds of horn related stuff. I suppose it is reliable source, but need to be careful copy pasting here since the info is scattered through out. Here is another one relevant on the debate
"
The throat impedance of an exponential
horn is shown in Fig. 2. Above the cutoff frequency, the throat resistance rises
quickly, and the horn starts to load the
driver at a much lower frequency than
the corresponding conical horn. In the
case shown, the exponential horn throat
resistance reaches 80% of its final value
at 270Hz, while the conical horn reaches
the same value at about 1200Hz.
An infinite horn will not transmit
anything below cutoff, but it’s a different
matter with a finite horn, as you will see
later.
"
...
"
Finite horns will transmit
sound below their cutoff frequency. This can be explained as
follows: the horn is an acoustical transformer, transforming the
high impedance at the throat to
a low impedance at the mouth.
But this applies only above cutoff.
Below cutoff there is no transformer action, and the horn only
adds a mass reactance.
An infinite exponential horn
can be viewed as a finite exponential horn terminated by an infinite
one with the same cutoff. As you
have seen, the throat resistance
of an infinite exponential horn is
zero below cutoff, and the throat
resistance of the finite horn will
thus be zero. But if the impedance present at the mouth has a
non-zero resistance below cutoff,
a resistance will be present at the
throat.
"
So, when ever talking about cutoff there should be mention of exponential (or hyperbolic, or what ever in question) horn to avoid confusion what the cutoff is.
Here is interesting nugget:
...
"
Another factor you need to
consider is the termination at the
throat. If there is a mismatch between the driver and the horn,
the reflected waves traveling from
the mouth will again be reflected
when they reach the throat, producing standing waves in the
horn.
"
Mark100 has posted several times he didn't find any issue with square throat adapter (conical MEH). The quote reads throat mismatch is not a problem if there is no mouth reflection. There is long section in the text handling optimal mouth size of exponential horn and at the end of it says that big conical horns shouldn't have much mouth reflection. Observation from measurements fit the text nicely, at least in my mind. 🙂
..
"
These considerations are valid for
exponential horns. What, then, about
hyperbolic and conical horns?
Hyperbolic horns with T < 1
will approximate the exponential
horn expansion a certain distance
from the throat, and the mouth
termination conditions will be
similar to those for an exponential horn. Conical horns show
no sign of having an optimum
mouth size. As length and mouth
size increase, simulations show
that the throat impedance ripple
steadily decreases, and the horn
approaches the characteristics of
an infinite horn.
"
..
Anyway, fun compact paper on horns.
Last edited:
Second part of the text handles some other horn types like OS.
"
The greatest disadvantage of the OS
waveguide is that it is not suitable for
low-frequency use. Bass and lower midrange horns based on this horn type will
run into the same problems as conical
horns: the horns become very long and
narrow for good loading.
To sum up, the OS waveguide provides excellent directivity control and
fairly good loading at frequencies above
about 1kHz.
"
I read this to support my philosophy of course, can't have it all with one device in horn land either. Pick your poison, good treble or bass performance, or just use two different devices and have good both, just like with direct radiators. Of course one can choose and live with a trade-off, I just don't see the point why anyone would do this deliberately in this context (playing too low with a device sacrificing the top) other than showing off maybe. Single fullrange driver would be much easier and cheaper to implement with same trade-off, of course doesn't play as loud and is not much of a show off but the point source quality is the same. Vifa TC9 can do 300-20kHz and costs less than a packet of cigarettes, and fits palm of the hand.
Sometimes it looks like from the side that a fight on something is because the communication is hard to understand so wanted to maybe help on this, both sides. I'm not sure why I posted this reply, maybe to clarify and support my own thoughs? 😀 Back to work
"
The greatest disadvantage of the OS
waveguide is that it is not suitable for
low-frequency use. Bass and lower midrange horns based on this horn type will
run into the same problems as conical
horns: the horns become very long and
narrow for good loading.
To sum up, the OS waveguide provides excellent directivity control and
fairly good loading at frequencies above
about 1kHz.
"
I read this to support my philosophy of course, can't have it all with one device in horn land either. Pick your poison, good treble or bass performance, or just use two different devices and have good both, just like with direct radiators. Of course one can choose and live with a trade-off, I just don't see the point why anyone would do this deliberately in this context (playing too low with a device sacrificing the top) other than showing off maybe. Single fullrange driver would be much easier and cheaper to implement with same trade-off, of course doesn't play as loud and is not much of a show off but the point source quality is the same. Vifa TC9 can do 300-20kHz and costs less than a packet of cigarettes, and fits palm of the hand.
Sometimes it looks like from the side that a fight on something is because the communication is hard to understand so wanted to maybe help on this, both sides. I'm not sure why I posted this reply, maybe to clarify and support my own thoughs? 😀 Back to work
Last edited:
I'm not playing around. I have spent a fair bit of my time trying to help you and it feels like wasted effort. Perhaps others will continue to indulge you.
Attachments
I'm about to release an Ath version that incorporates driver lumped element models. It simulates the "real" SPL for a given driver, excursion and electrical impedance. I hope this will bring some more light to these debates once for all (provided there will be enough interest to participate in creating the driver models).
Last edited:
Does not elicit
You are implying I am wrong about something that I never said...You ask me wheres the "cutoff" on a horn profile that has no cutoff...
Sorta like aiming for even lower excursion in bass drivers by adding more bass drivers. Getting rid of Distortion, but costing more money and space. Make sure you know what you are loosing....in order to gain a better impulse response.
The cutoff frequency of an infinite conical horn is given by k * xt = 1, where:
k = wave number = 2 * Pi * f / c
xt = distance from the apex to the throat
c = speed of sound
Therefore:
fc = c / (2 * Pi * xt)
In the attached example:
c = 34400 cm / sec
xt = 10 cm
fc = 34400 / (2 * Pi * 10) = 547.49 Hz
