Did You Get That to Work?
Tyimo,
Did you get around to modeling that in MathCad? I have tried it with both front and back loaded horns. I had much better results with FLHs. You can read my paper HERE in this post :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=64450
If you want to see the results I achieved in a BLH, I can post that too.
John
Tyimo,
Did you get around to modeling that in MathCad? I have tried it with both front and back loaded horns. I had much better results with FLHs. You can read my paper HERE in this post :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=64450
If you want to see the results I achieved in a BLH, I can post that too.
John
Retsel
I own Hedlund Horns and have enjoyed music played through these speakers for years. Originally, I had Lowther DX2s, but later on I upgraded to the EX4s. I removed the back baffle and tried the bullet diffuser and liked this configuration better so I am using DX4s now (EX4s can be easily converted to DX4s).
According to Jan Hedlund, the advantage of the Hedlund Horns is its ability to transmit the upper and mid bass through the horn without bends avoiding early reflections that a folded horn would create. You still have some early reflections created by the compression chamber, which can be minimized by a thin layer of felt on the inside surfaces of the compression chamber. The disadvantage of the Hedlund Horn is the very tall structure and difficulty in building them.
The Hedlund Horn is capable of delivering bass flat down to about 70 - 100 hz, thus a subwoofer is necessary for the deep bass to get a balanced sound. A super tweater is helpful as well, but more of a luxury. The miracle of the back loaded horn is that it evens out the frequency response so you simply install the drivers and you are done (except for the need to throw in a couple of sandbags in the compression chamber to adapt the Hedlund Horns to the DX4 driver). No crossover or other frequency adjustment is necessary. That does not mean that the frequency resposnse is perfectly flat, but noone who has listened to my combination of subwoofer with Hedlund Horns has ever suggested frequency correction. One of the reasons for the magic of these speakers is that no crossover components are in the signal path thus giving a very transparent presentation. This is different from other speakers which use the Lowther DX4 drivers which require frequency correction to make them listenable (open baffle, TL, sealed box, bass reflex). Just to be clear, Hedlund Horns don't need to be in the corner or against a side wall to make the frequency response flat, they are about 4 feet away from the back wall and 3 feet from the side walls.
I am currently trying my Lowther DX4s on open baffle (Basszilla was my starting point). I don't think that the midbass is as good, but the upper frequencies seem to be better rendered (getting rid of the box has its benefits). I also need a single inductor to even out the frequency response thus adding a crossover component in the signal path. Interestingly, Paul Butterfield used a set of Lowther DX4s on open baffle with the Hedlund Horns as bass transducers. I can now see the wisdom in this.
Retsel
I own Hedlund Horns and have enjoyed music played through these speakers for years. Originally, I had Lowther DX2s, but later on I upgraded to the EX4s. I removed the back baffle and tried the bullet diffuser and liked this configuration better so I am using DX4s now (EX4s can be easily converted to DX4s).
According to Jan Hedlund, the advantage of the Hedlund Horns is its ability to transmit the upper and mid bass through the horn without bends avoiding early reflections that a folded horn would create. You still have some early reflections created by the compression chamber, which can be minimized by a thin layer of felt on the inside surfaces of the compression chamber. The disadvantage of the Hedlund Horn is the very tall structure and difficulty in building them.
The Hedlund Horn is capable of delivering bass flat down to about 70 - 100 hz, thus a subwoofer is necessary for the deep bass to get a balanced sound. A super tweater is helpful as well, but more of a luxury. The miracle of the back loaded horn is that it evens out the frequency response so you simply install the drivers and you are done (except for the need to throw in a couple of sandbags in the compression chamber to adapt the Hedlund Horns to the DX4 driver). No crossover or other frequency adjustment is necessary. That does not mean that the frequency resposnse is perfectly flat, but noone who has listened to my combination of subwoofer with Hedlund Horns has ever suggested frequency correction. One of the reasons for the magic of these speakers is that no crossover components are in the signal path thus giving a very transparent presentation. This is different from other speakers which use the Lowther DX4 drivers which require frequency correction to make them listenable (open baffle, TL, sealed box, bass reflex). Just to be clear, Hedlund Horns don't need to be in the corner or against a side wall to make the frequency response flat, they are about 4 feet away from the back wall and 3 feet from the side walls.
I am currently trying my Lowther DX4s on open baffle (Basszilla was my starting point). I don't think that the midbass is as good, but the upper frequencies seem to be better rendered (getting rid of the box has its benefits). I also need a single inductor to even out the frequency response thus adding a crossover component in the signal path. Interestingly, Paul Butterfield used a set of Lowther DX4s on open baffle with the Hedlund Horns as bass transducers. I can now see the wisdom in this.
Retsel
Retsel
One more thing. The orignal request was to know the back loaded horn designs which can attain a flat frequency response down to 40 hz. Besides the Klein Horn which is a monster to build, I would suggest the Big Fun Horn. The Big Fun Horn needs to be in corners to take advantage of the corner loading for the vents of the back horn. But people who have used the Big Fun Horn report flat frequency response down in the low 40s.
Retsel
One more thing. The orignal request was to know the back loaded horn designs which can attain a flat frequency response down to 40 hz. Besides the Klein Horn which is a monster to build, I would suggest the Big Fun Horn. The Big Fun Horn needs to be in corners to take advantage of the corner loading for the vents of the back horn. But people who have used the Big Fun Horn report flat frequency response down in the low 40s.
Retsel
Hi Retsel
Thank you for the detailed response regarding the Hedlund horns.
You mentioned earlier that you cross your sub at "around 40hz" --and that the horns are flat to 70hz.
What about 40hz - 70hz. Is that where fine tuning the sub comes in? Wouldn't that be considered by some as "a hole"?
Thank you for your response...
Joe
Thank you for the detailed response regarding the Hedlund horns.
You mentioned earlier that you cross your sub at "around 40hz" --and that the horns are flat to 70hz.
What about 40hz - 70hz. Is that where fine tuning the sub comes in? Wouldn't that be considered by some as "a hole"?
Thank you for your response...
Joe
Retsel
No. 40 hz (38 hz to be exact) is where there is a seamless integration between the Hedlund Horn and the subwoofer I was using. You don't want to set the crossover between the two at the same point or else you will have overlap and boomy bass. This still seems to be pretty far apart so perhaps Genesis (it was a Genesis 900 subwoofer) expressed the crossover point at the beginning of the rolloff instead of at the -3db point, I don't know. But I had the most seamless bass (and among the two best) I have ever heard.
Retsel
No. 40 hz (38 hz to be exact) is where there is a seamless integration between the Hedlund Horn and the subwoofer I was using. You don't want to set the crossover between the two at the same point or else you will have overlap and boomy bass. This still seems to be pretty far apart so perhaps Genesis (it was a Genesis 900 subwoofer) expressed the crossover point at the beginning of the rolloff instead of at the -3db point, I don't know. But I had the most seamless bass (and among the two best) I have ever heard.
Retsel
Hi John!
Retsel!
Thanks a lot for your for detailed rewiew!!
I wouldn't thought that the Hedlund can not reach the "magic" 40Hz.....
I am thinking about some modifications on the Nagaoka D-37, with bigger chamber al'a Klangform methode.
Greets:
Tyimo
What do you mean on modeling? The Hedlund?
Retsel!
Thanks a lot for your for detailed rewiew!!
I wouldn't thought that the Hedlund can not reach the "magic" 40Hz.....
I am thinking about some modifications on the Nagaoka D-37, with bigger chamber al'a Klangform methode.
Greets:
Tyimo
Hi Gastón!
Last time maybe you was asking me, but sorry I was busy and it looks so that this thread is dead.
I don't know the exact line lenght, so I just used a roughly lenght.
I don't know how much influence has the bends to the line lenght compare to a stright horn. I read so many thinks about this "problem" pro and contra....
Greets:
Tyimo
Last time maybe you was asking me, but sorry I was busy and it looks so that this thread is dead.
I don't know the exact line lenght, so I just used a roughly lenght.
I don't know how much influence has the bends to the line lenght compare to a stright horn. I read so many thinks about this "problem" pro and contra....
Greets:
Tyimo
ît was in 2000 and one of my first tries. A very expensive failure. It never worked well and that was the begining of my own deeper thougts ablut horns and how they could work. In several tries before a friend of mine and I have tried bigger chambers behind the speaker. After that he have changed the lenght and started with calculations. Now I am buling horns like the Replikon, FX-200 horn and so on. And now I can listen to them myselve.
ggg that was a very interesting time and I often thing back to that time. I have been more often in the basement to build than at my girlfriends apartment. ggg how times can change.
smile Till
ggg that was a very interesting time and I often thing back to that time. I have been more often in the basement to build than at my girlfriends apartment. ggg how times can change.
smile Till
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