More suited to hear the fast transients / low distortion and details
to lower bandwidth of midrange or tweeters.
More common for tweeters especially to cross over lower.
And includes the other directionality tradeoffs.
Rather 50 or 100 or even 200 to 400Hz
the so called fast attack and low distortion bass
is still impressive with horn systems.
Ironically the so called off topic comments.
Appear again and again, specially using a drum
track for example. Even if the response is not this or not that.
Drums and certain instrument really wake up with
horns. And enjoyable experience.
As for suitable midrange tractrix.
It is almost the basic point.
Drivers with rising high frequency response
actually yield a flatter response with the Horn.
Your almost looking for a rising response.
Since tractrix mainly will emphasis low-end
but with limited efficiency. And the top end
isnt much more than the direct radiator itself.
No free lunch unfortunately.
Tractrix seems the answer to smaller, shorter
and deeper frequency response bass bins.
Unfortunately efficiency is limited or part of the tradeoff.
And bass bins lean towards a more efficiency bandpass.
So the rear/back wave thing is already been done.
Just described as a different method and many many more
correction factors.
to lower bandwidth of midrange or tweeters.
More common for tweeters especially to cross over lower.
And includes the other directionality tradeoffs.
Rather 50 or 100 or even 200 to 400Hz
the so called fast attack and low distortion bass
is still impressive with horn systems.
Ironically the so called off topic comments.
Appear again and again, specially using a drum
track for example. Even if the response is not this or not that.
Drums and certain instrument really wake up with
horns. And enjoyable experience.
As for suitable midrange tractrix.
It is almost the basic point.
Drivers with rising high frequency response
actually yield a flatter response with the Horn.
Your almost looking for a rising response.
Since tractrix mainly will emphasis low-end
but with limited efficiency. And the top end
isnt much more than the direct radiator itself.
No free lunch unfortunately.
Tractrix seems the answer to smaller, shorter
and deeper frequency response bass bins.
Unfortunately efficiency is limited or part of the tradeoff.
And bass bins lean towards a more efficiency bandpass.
So the rear/back wave thing is already been done.
Just described as a different method and many many more
correction factors.
The driver. The sound of the horn will be dominated by the driver sonics (since it is mostly a direct radiator. The driver does not impact the midrande leakage if the Back nhorn is too smooth.
Midrange leakage — most of it anyway — depends on the horn, not the driver. If the transiton from direct to horn output ia too high one has problems withbgroup delay (the horn output is an odd number of half wavelengths behind the direct sound. And a horn is on ly good fro 3 or 4 octaves. Too much mid out of the horn and you sacrifice bass extention.
Hedlund for instanbce goes to 80 Hz?
dave
@planet10
Sorry Dave but I have a hard time following what you write.
Writing from a smartphone skipping words?
Since we are talking about horn I expect it to amplify the sonics from the driver.
Otherwise it is a resonant duct with very coloured sound of it's own.
The linearity for the horn is extremely important for the functionality and have an impact on the sound quality.
You say midrange leakage and say it's bad.
I say midrange output and say it's necessary to have it and balance the amount to the driver and the design of the horn.
It's an integral and necessary part of the total output IMO.
Group delay is not that big of a problem.
You do not sacrifice bass extension when letting through midrange. Not if you adjust it by selecting volume of compression chamber and throat area correctly.
Both have an influence and needs to be selected with care to get a seemless transition from horn output and the driver.
Horn length vs. mouth area have a big impact on bass output and extension, and I have never seen that I loose bass extension nor amplitude as a consequence of how much midrange output I select to have.
Regarding Hedlund horn it extends down to about 75 Hz so you are quite right about 80 Hz.
Depending on room size room gain kicks in at 40-50 Hz, which would be the optimum extension, so Hedlund horn have a lowered shelf of -12dB from approx. 20-55 Hz and will benefit from a good sub if you want to have the full fullrange.
Most builders are satisfied with them as they are, but some need that extra bass extension.
The length was selected solely because of room height, design principle of no folds and by choice in order to not have my listening position too far away from the speaker.
As a rule of thumb I say that listening position should be at least 1,2 times the horns length to minimize the delay problem.
Sorry Dave but I have a hard time following what you write.
Writing from a smartphone skipping words?
Since we are talking about horn I expect it to amplify the sonics from the driver.
Otherwise it is a resonant duct with very coloured sound of it's own.
The linearity for the horn is extremely important for the functionality and have an impact on the sound quality.
You say midrange leakage and say it's bad.
I say midrange output and say it's necessary to have it and balance the amount to the driver and the design of the horn.
It's an integral and necessary part of the total output IMO.
Group delay is not that big of a problem.
You do not sacrifice bass extension when letting through midrange. Not if you adjust it by selecting volume of compression chamber and throat area correctly.
Both have an influence and needs to be selected with care to get a seemless transition from horn output and the driver.
Horn length vs. mouth area have a big impact on bass output and extension, and I have never seen that I loose bass extension nor amplitude as a consequence of how much midrange output I select to have.
Regarding Hedlund horn it extends down to about 75 Hz so you are quite right about 80 Hz.
Depending on room size room gain kicks in at 40-50 Hz, which would be the optimum extension, so Hedlund horn have a lowered shelf of -12dB from approx. 20-55 Hz and will benefit from a good sub if you want to have the full fullrange.
Most builders are satisfied with them as they are, but some need that extra bass extension.
The length was selected solely because of room height, design principle of no folds and by choice in order to not have my listening position too far away from the speaker.
As a rule of thumb I say that listening position should be at least 1,2 times the horns length to minimize the delay problem.
No, they need to reduce the level where they are much too loud. The measurement graphs omit many resonances due smoothing btw.
It is 'necessary' because of the many shortcomings of the driver. To compensate for this, you sacrifice linearity, phase (which is one of the best aspects of a FR), decay, Impulse response and stage performance. You also don't know what causes what (or just ignore it). @planet10 is completely right about mid leakage. You might like it like it is and that is perfectly fine by me but don't try to deny the truth, the downsides and don't try brute force others only your point of view is the only correct one.
@ICG
Absolutely not.
From the start in 1930 Lowther have always been designed to be used as is without crossover and without damping.
Depending on driver, some need a short front horn and a rear horn while others only need rear horn.
Drivers and horns together are supposed to be designed to have a flat in room frequency response together.
One of them can be used with direct radiation only, and that is PM6ATi. Ask Nelson Pass about it. He has a few of them.
The rise above 1-2kHz is not as bad as you think.
Measurement are on axis, and beaming starts approx. 1,5kHz so total radiation power is basically 6dB down in total @10kHz.
You really need to learn what Lowther is, learn about their heritage and long time pursuit to make the perfect fullrange driver.
Absolutely not.
From the start in 1930 Lowther have always been designed to be used as is without crossover and without damping.
Depending on driver, some need a short front horn and a rear horn while others only need rear horn.
Drivers and horns together are supposed to be designed to have a flat in room frequency response together.
One of them can be used with direct radiation only, and that is PM6ATi. Ask Nelson Pass about it. He has a few of them.
The rise above 1-2kHz is not as bad as you think.
Measurement are on axis, and beaming starts approx. 1,5kHz so total radiation power is basically 6dB down in total @10kHz.
You really need to learn what Lowther is, learn about their heritage and long time pursuit to make the perfect fullrange driver.
How does making something wrong for a long time it any better? 1930 had the necessity for settling for it because the lack of amp power - which was over 20 years later.
Well, if all around you say the opposite of your perceived 'facts', don't you think it's maybe you and not everyone else? It's very easy to verify what is wrong and what is not. Start measuring, exclude each factor. I don't mind if you don't admit anything here, just do it for yourself. Nobody is trying to convince you to change what you like but don't claim everything else and everybody else is wrong.
Must others endure the bickering going on in this thread? We'd be happy to arrange somewhere else for you to play.Folks, lets shoot for constructive interference on this thread ) If any of you feel like an apology is in order, its highly encouraged, and will keep the collective phase coherence in order. We can all get a little resonant at times )
After all I still need input on a little PA unitized box that can be vertically arrayed, actually fits in human size passenger cars, and squeezes out gains from a curved horn of some kind, sums the rear 1/4 wave, and possible driver summing.
The goal being to have a well put together mid/top or semi full range design for the community at large here. with plans, CNC data etc easily accessible.
After all I still need input on a little PA unitized box that can be vertically arrayed, actually fits in human size passenger cars, and squeezes out gains from a curved horn of some kind, sums the rear 1/4 wave, and possible driver summing.
The goal being to have a well put together mid/top or semi full range design for the community at large here. with plans, CNC data etc easily accessible.
Ok lets get this thread back on track..
Based on all of the acoustic design principals (that I understand so far anyway) the attached design is full of db gains for a PA mid/high. . At this point Im afraid to suggest adding one more horn baffle on each side
Can I expect to get any meaningful extra db and cut off increase from the rear wave? or is it just creating phase and other problems, and I should just stick with front radiating? Assume an 800-1000mm outer dimension box width.
Based on all of the acoustic design principals (that I understand so far anyway) the attached design is full of db gains for a PA mid/high. . At this point Im afraid to suggest adding one more horn baffle on each side
Can I expect to get any meaningful extra db and cut off increase from the rear wave? or is it just creating phase and other problems, and I should just stick with front radiating? Assume an 800-1000mm outer dimension box width.
Attachments
The rule of thumb, the mouth perimeter is the LF cutoff wavelength.
It is more complicated than that thou, here a classical treatise by Dinsdale in Wireless World: https://p10hifi.net/TLS/downloads/Dinsdale-Horns-3parts.pdf
dave
It is more complicated than that thou, here a classical treatise by Dinsdale in Wireless World: https://p10hifi.net/TLS/downloads/Dinsdale-Horns-3parts.pdf
dave
Last edited by a moderator:
Personally, using a front horn, I would focus more on directivity control than on loading. As @ICG already stated, a front loading horn has its cut off, and you make things worse below the cut-off. What I mean is to match directivity of the LF to MF/HF at x-over point and then it turns out to be more or less a waveguide for LF. It is easy to design a waveguide that does load less in the intended frequency range.
What is the difference between a wave guide and a horn mouth for low/mid? Doesnt the wave guide suffer the same size vs cutoff constraints? or are you talking about a HF wave guide?
if your referring to LF/mid, what are the design parameters for a wave guide? just angled dispersion baffles at some degree at some depth?
if your referring to LF/mid, what are the design parameters for a wave guide? just angled dispersion baffles at some degree at some depth?