First, every horn profile has advantages & disadvantages. I was facinated by the tractrix when i first learned of horns and designed both folded BLHs & mids for a PA.
Can they be folded? Depends on the frequency range — wavelengths in relation to the horn size. HF horns are typically too short to bother folding, so let’s say we are talking about bass horns.
The horns in Post #5 are midhorns and not really folded, but curved, gentle changes in the direction, no sharpchanges as we proceed down the horn.
The Hedlund & Del Rio are similar to The Daleks, https://frugal-horn.com/daleks.html
All 3 of these are “air cavity” back-loaded horn that try to be as smooth as possible. Only bass frequencies are horn loaded (they are direct radiators above that frequency) , typically below n250-300 Hz. The smoothness is actually counter-productive as it tries to pass maximum HFs, notsomething you really want to come out the mouth.
Something like Vulcan, while less “intuitive”, is more effective as the expansion at every sharp bend acts a LP filter.
dave
Can they be folded? Depends on the frequency range — wavelengths in relation to the horn size. HF horns are typically too short to bother folding, so let’s say we are talking about bass horns.
The horns in Post #5 are midhorns and not really folded, but curved, gentle changes in the direction, no sharpchanges as we proceed down the horn.
The Hedlund & Del Rio are similar to The Daleks, https://frugal-horn.com/daleks.html
All 3 of these are “air cavity” back-loaded horn that try to be as smooth as possible. Only bass frequencies are horn loaded (they are direct radiators above that frequency) , typically below n250-300 Hz. The smoothness is actually counter-productive as it tries to pass maximum HFs, notsomething you really want to come out the mouth.
Something like Vulcan, while less “intuitive”, is more effective as the expansion at every sharp bend acts a LP filter.
dave
Last edited:
Because too much HF is radiated out the mouth — and a front mouth exacerbates things. Not taking advantage of a rear mouth typically means an octave or more less bass extention.
Given the frequecnies involved the curves in Dalek are close enuff to be considered really close to the other 2.
dave
Yes, and that's the problem instead of the solution. You don't want a BL horn to reproduce the midrange from the horn, you rather want it to be weeded out to kill the mid-resonances and out of phase sound. It's a fact a folded horn reduces the midrange more than a bent one where you have to dampen more to get rid of it. And it's typical most horns use mats at the bends, that's for a reason.
Well, I've seen some dudes who built their home around a horn, making the horn straight below the floor or along the walls. That's the point where your speakers become real-estate.
Yes, I have seen that the common understanding is that you should avoid having too much midrange comming out from the mouth.
I say that it depends on which driver you design your horn for.
I rarely use anything but Lowther, and PM2A, PM4, PM5, DX3, DX4 need some of that blend of midrange from the mouth to perform their best.
It's a matter of design and not a matter of principle.
If you need some midrange support from the mouth you better avoid folds and try your best to have benign bends to get the best end result.
Only within the envelope of the driver. Lowthers suffer from the ame leakage, they are not magic.
dave
@planet10
I didn't understand that.
What doesn't affect how the horn affects the design?
Physics is physics, and it's a matter of design and preference how you tune your horn to work optimaly with a certain driver.
Just to say that midrange output from the horn is bad and to be avoided is not a proper statement to make since it's not true.
When starting to folding a horn I understand that you do not want the horn to have output up in the midrange because it will not be linear.
I have no problem with that, but I have a problem when someone continously state that midrange output from a BL horn is bad regardless of how it is tuned and designed.
If you can make a horn design that is linear your very well can let the horn go up a bit in the midrange.
With some drivers like the better Lowther drivers it's mandatory if you want a balanced and neutral sound.
I didn't understand that.
What doesn't affect how the horn affects the design?
Physics is physics, and it's a matter of design and preference how you tune your horn to work optimaly with a certain driver.
Just to say that midrange output from the horn is bad and to be avoided is not a proper statement to make since it's not true.
When starting to folding a horn I understand that you do not want the horn to have output up in the midrange because it will not be linear.
I have no problem with that, but I have a problem when someone continously state that midrange output from a BL horn is bad regardless of how it is tuned and designed.
If you can make a horn design that is linear your very well can let the horn go up a bit in the midrange.
With some drivers like the better Lowther drivers it's mandatory if you want a balanced and neutral sound.
Last edited:
@flex2
When you like what you hear, then ok. But IMO a BL horn should only help the driver at lower frequencies and never in the MR. The reason is the much longer path length for the BLH compared to the direct radiation. You don't want to mix this up. It will never be a good thing. Also the effect of secondary sound sources are not really a good thing.
Anyway, if you ever compare such tiny speaker chassis supported by a BLH with a 15" woofer and a horn on top of that you would recognize what these tiny chassis will never ever be able to reproduce.: good bass. I have also had such a speaker with a whizzer cone. Simply terrible to listen to over a longer time.
When you like what you hear, then ok. But IMO a BL horn should only help the driver at lower frequencies and never in the MR. The reason is the much longer path length for the BLH compared to the direct radiation. You don't want to mix this up. It will never be a good thing. Also the effect of secondary sound sources are not really a good thing.
Anyway, if you ever compare such tiny speaker chassis supported by a BLH with a 15" woofer and a horn on top of that you would recognize what these tiny chassis will never ever be able to reproduce.: good bass. I have also had such a speaker with a whizzer cone. Simply terrible to listen to over a longer time.
@docali
As I say, I don't accept that assumption and IMO you are incorrect since it depends on the driver used.
Some drivers need that support to have a chance to sound neutral.
Do not make the mistake to just say something out of principle. Investigate and build yourself and get knowledge.
If you read my first inputs in this thread you will see what I think of this threads original design. I think we are on common ground regarding their potential to produce good bass. Basically impossible.
Some examples that eighter need a front horn to lift 200-2khz region or a BL that extends up in the midrange, or both.
Depends on the frequency response you want to end up with.
I understand the reason for your thoughts, but in practice it isn't so important.
Overall tonality is much more important.
In practice, if you sit further away from the horn than the horn is long you have little problem with the combined result of the output from the mouth and the driver.
Both these Lowther drivers need some midrange support from the horn. PM4A more than DX2, but neighter will sound good if they don't have it.
As I say, I don't accept that assumption and IMO you are incorrect since it depends on the driver used.
Some drivers need that support to have a chance to sound neutral.
Do not make the mistake to just say something out of principle. Investigate and build yourself and get knowledge.
If you read my first inputs in this thread you will see what I think of this threads original design. I think we are on common ground regarding their potential to produce good bass. Basically impossible.
Some examples that eighter need a front horn to lift 200-2khz region or a BL that extends up in the midrange, or both.
Depends on the frequency response you want to end up with.
I understand the reason for your thoughts, but in practice it isn't so important.
Overall tonality is much more important.
In practice, if you sit further away from the horn than the horn is long you have little problem with the combined result of the output from the mouth and the driver.
Both these Lowther drivers need some midrange support from the horn. PM4A more than DX2, but neighter will sound good if they don't have it.
Last edited:
Tell me what is good with these drivers the the point of design principles wrt to the whole speaker? I don't understand that you accept such a bad frequency response. The driver is way too hot at HF and the big issue is that it starts it work (whizzer cone) suddenly at around 2k. And you still need a SHT above 8k. These speakers have 5 major issues (maybe more).
1. Way too small driver surface area, so not able to reproduce perfect bass (higher levels and distortion free).
2. The back loaded horn always has issues with internal reflections and resonances, especially for a folded construction.
3. If you let pass MR out of your BLH then you will get cancellations at certain frequencies due to different path lengths (sound of the two sources out of phase at your ears.) A BLH only works sufficiently good for LF.
4. The sudden break-in of the whizzer cone. You hear that! I owned a BLH myself years ago.
5. Lack of HF response. You will need another sound source, a tweeter. Very hard to make this right at HF.
1. Way too small driver surface area, so not able to reproduce perfect bass (higher levels and distortion free).
2. The back loaded horn always has issues with internal reflections and resonances, especially for a folded construction.
3. If you let pass MR out of your BLH then you will get cancellations at certain frequencies due to different path lengths (sound of the two sources out of phase at your ears.) A BLH only works sufficiently good for LF.
4. The sudden break-in of the whizzer cone. You hear that! I owned a BLH myself years ago.
5. Lack of HF response. You will need another sound source, a tweeter. Very hard to make this right at HF.
@docali
Now we really are out of topic in this thread, but I will give you a short one.
Yes, Lowther drivers have a lot of limitations and I haven't been building with them for a long time.
But they have some capabilities that are best in class regardless of principle.
Directness, speed and "see through" very few other drivers can offer.
If handled right they can sound very good. Listen to earlier sound clips in this thread.
Here is another one showing off Lowthers AudioVectors ability to produce bass.
Quite impressive for that lousy and bad driver, right?
Very low distortion and impeccable attack that you have a hard time to find in even a 15" driver
Normal voice coil movement is usually less than +/-1mm and sensitivity at +100dB for a watt.
Sure you have no deep bass, but why not complement with a good sub?
Now we really are out of topic in this thread, but I will give you a short one.
Yes, Lowther drivers have a lot of limitations and I haven't been building with them for a long time.
But they have some capabilities that are best in class regardless of principle.
Directness, speed and "see through" very few other drivers can offer.
If handled right they can sound very good. Listen to earlier sound clips in this thread.
Here is another one showing off Lowthers AudioVectors ability to produce bass.
Quite impressive for that lousy and bad driver, right?
Very low distortion and impeccable attack that you have a hard time to find in even a 15" driver
Normal voice coil movement is usually less than +/-1mm and sensitivity at +100dB for a watt.
Sure you have no deep bass, but why not complement with a good sub?
What is the importance of loading to you? What is the expected purpose of the horn in general?
What do you mean by this, how would you use them?
hornresp could probably answer some of the dimensional questions.. levels, excursion, power needed etc..
https://www.diyaudio.com/community/threads/hornresp.119854/unread
Absolutely, if you don't intend to cover bass register with it, or use Beyma TPL-150H. That driver will outperform most compression drivers in a horn.
Specially for home use.
I do agree with you, but that was not what this thread was about. It was about folding a TracTrix horn.
The thing about Lowther is to use the driver without crossover fullrange.
Of course you can do better, but they are not bad, and has a solid group of followers.
@AllenB
As I understand turboblast now are thinking about using both sides of the driver. Front in a TracTrix horn and the rear in a back loaded horn.
Not a bad idea...
https://www.springair.de/en/lowther-audiovector-symphonic/h70764
The soundclip above are from such a speaker, the Lowther Audiovector. Front horn (TracTrix?), 1/4 wave back loaded horn and direct radiation in combination.
To me they are great fun, but not perfect.
Last edited: