Hey Lynn,
Found your old post from 2009 and this idea resembles the one I did in Hornresp, having seen and listened to 816/416.
By using trial and error for a l´Cleach midbasshorn with the 414´s in my stash, I didn´t get optimal but acceptable results in 1,0*PI.
1,0 as they are to be placed on the floor against the sidewall due to limited space. But this one only works for midbass with a 60dm3 vented box. It will not reach 500Hz, barely 400Hz.
Also did a sim combining the horns with the Petite Onken and the results where barely acceptable.
Still pondering the optimum match for the AH425 with Altec/GPA 288, or Radian 745P 1.4" driver. Based on measurements and subjective reports from Bjorn Kolbrek and Gary Dahl, the AH425 easily covers the range from 700 Hz to 10 kHz with quite flat response, no requirement for equalization, and a straightforward 3rd-order highpass filter.
Gary Dahl (who posts on this forum) is using a combination of the AESpeakers TD15M and TD15H, with the TD15M in a closed box and the TD15H with a pair of AESpeakers 15" passive radiators. The TD15H is self-powered with a "plate amp" that samples the electrical drive to the TD15M, but Gary is not entirely satisfied with the sound of the plate amp.
Both of us wish the efficiency was a bit higher; the horn is being padded down by 13~15 dB, which seems more than a bit wasteful. Three different ways to get the efficiency of the bass module higher would be a short horn, which has uneven response; some kind of folded backhorn on a Lowther-type driver (which also has uneven response); or a quartet of prosound-style 12" drivers in a closed or resistive-vented box. That would get the efficiency in the 70~700 Hz range up beyond 100 dB/metre/watt, and provide better match to the large-format horn.
Of course it is possible to build a straight horn that goes down to 70 Hz - but they are very large, and folding a bass horn puts notches and reflections in frequency and time response. Notwithstanding that, Bjorn Kolbrek is using the AH425 quite successfully with his folded basshorn. Hmm ... I wonder if anyone has designed a spiral horn that covers the 70~700 Hz range?
P.S. Although the lumps, bumps and notches of folded basshorns certainly look ugly in simulations and measurements, every time I hear one, I'm not bothered by the uneven response at all. What I notice is the clarity and crispness of the bass, so different from the usual low-efficiency murk and blurry sound. Maybe because the lumps and bumps merge with the uneven room response, and falls in a frequency range where response variations are not as audible as the more critical 1~5 kHz range?
P.P.S. I should add that both Bjorn Kolbrek and Martin Seddon (of Azurahorn) strongly urged me to try basshorns with the AH425, which is the setup they are using with their own AH425's. Something about the dynamics of direct-radiators not quite matching the HF horn ... there might be something to that. In principle, a direct-radiator array should sound the same as a horn, in practice, maybe not.
Gary Dahl (who posts on this forum) is using a combination of the AESpeakers TD15M and TD15H, with the TD15M in a closed box and the TD15H with a pair of AESpeakers 15" passive radiators. The TD15H is self-powered with a "plate amp" that samples the electrical drive to the TD15M, but Gary is not entirely satisfied with the sound of the plate amp.
Both of us wish the efficiency was a bit higher; the horn is being padded down by 13~15 dB, which seems more than a bit wasteful. Three different ways to get the efficiency of the bass module higher would be a short horn, which has uneven response; some kind of folded backhorn on a Lowther-type driver (which also has uneven response); or a quartet of prosound-style 12" drivers in a closed or resistive-vented box. That would get the efficiency in the 70~700 Hz range up beyond 100 dB/metre/watt, and provide better match to the large-format horn.
Of course it is possible to build a straight horn that goes down to 70 Hz - but they are very large, and folding a bass horn puts notches and reflections in frequency and time response. Notwithstanding that, Bjorn Kolbrek is using the AH425 quite successfully with his folded basshorn. Hmm ... I wonder if anyone has designed a spiral horn that covers the 70~700 Hz range?
P.S. Although the lumps, bumps and notches of folded basshorns certainly look ugly in simulations and measurements, every time I hear one, I'm not bothered by the uneven response at all. What I notice is the clarity and crispness of the bass, so different from the usual low-efficiency murk and blurry sound. Maybe because the lumps and bumps merge with the uneven room response, and falls in a frequency range where response variations are not as audible as the more critical 1~5 kHz range?
P.P.S. I should add that both Bjorn Kolbrek and Martin Seddon (of Azurahorn) strongly urged me to try basshorns with the AH425, which is the setup they are using with their own AH425's. Something about the dynamics of direct-radiators not quite matching the HF horn ... there might be something to that. In principle, a direct-radiator array should sound the same as a horn, in practice, maybe not.
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Definitely there is a good point of transition in horn design where the qualities of both types of design can be accomplisted. It does take some experiementing to find that point. For best performance, the horn/guide type base would probably be integrated with the room.
I find it interesting that I've always liked the bass of Klipschorns, Belle Klipsch, and La Scalas, yet I know the frequency response of these folded horns is terrible, with 10~20 dB holes in the response, especially where they struggle to meet the bottom of the modest-sized midhorn. On paper, these should be horrible-sounding systems, but despite that, the bass range has its charms. Never much cared for the mids or highs, but the bass has always appealed to me, despite the measurements. So if Bjorn Kolbrek, who knows his horns, uses a folded bass horn in his personal system, that's something I have to take seriously.
Subjectively, the quality I like best is they play quietly (at background-music levels) while retaining crispness and clarity. This is where direct-radiators really fall down badly, for reasons that have never been clear to me. That quality alone makes me wonder if a direct-radiator array of four 12" drivers would really sound the same as a bass horn at low levels.
I take it seriously when measurements and subjective impressions are in conflict; the data is trying to tell you something - and no, I'm not a big believer in "euphonic colorations". Most loudspeaker and electronic colorations degrade the sound, not improve it. If it sounds more natural, the tonality has more shimmer, sparkle, and color, and is just plain more beautiful, that's not a coloration - instead, something is going right! But what? The trick is to find what it is. Lower IM distortion? Less energy storage in the diaphragm? Less cabinet coloration?
One area that deserves more study is the subjective impression of larger versus smaller effective radiating areas. Small drivers sound - well - small, no matter how loudly they are played. Large drivers, and more particularly, horns with large mouths, have a certain spacious and effortless quality that smaller systems just never attain, no matter how refined they are. I suspect the ear can directly perceive the apparent source size of the wavefront, and is not fooled by a point-source pretending to be larger than it really is. One example - mono sound is very unpleasant from a single mini-monitor, sounding ridiculously compressed and "squeezed", like it's coming from a keyhole. By contrast, mono sounds pretty natural coming from a larger loudspeaker.
Subjectively, the quality I like best is they play quietly (at background-music levels) while retaining crispness and clarity. This is where direct-radiators really fall down badly, for reasons that have never been clear to me. That quality alone makes me wonder if a direct-radiator array of four 12" drivers would really sound the same as a bass horn at low levels.
I take it seriously when measurements and subjective impressions are in conflict; the data is trying to tell you something - and no, I'm not a big believer in "euphonic colorations". Most loudspeaker and electronic colorations degrade the sound, not improve it. If it sounds more natural, the tonality has more shimmer, sparkle, and color, and is just plain more beautiful, that's not a coloration - instead, something is going right! But what? The trick is to find what it is. Lower IM distortion? Less energy storage in the diaphragm? Less cabinet coloration?
One area that deserves more study is the subjective impression of larger versus smaller effective radiating areas. Small drivers sound - well - small, no matter how loudly they are played. Large drivers, and more particularly, horns with large mouths, have a certain spacious and effortless quality that smaller systems just never attain, no matter how refined they are. I suspect the ear can directly perceive the apparent source size of the wavefront, and is not fooled by a point-source pretending to be larger than it really is. One example - mono sound is very unpleasant from a single mini-monitor, sounding ridiculously compressed and "squeezed", like it's coming from a keyhole. By contrast, mono sounds pretty natural coming from a larger loudspeaker.
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Continuing in this direction, one interesting difference between a compact point-source radiator (one that is much smaller than the wavelengths it is emitting) and a larger source is how the early reflections behave differently. We don't have to guess where these come from; they are the floor bounce (the first reflection, typically arriving 2.5~2.8 mSec after the direct arrival, and only very slightly attenuated by carpeting), the reflection off the back wall, and the nearest sidewall.
These three reflections are the first to arrive in most listening rooms, and the ear gives strong preference to these earliest arriving sounds. The ear's preference for first-arriving sounds is why a time-averaging microphone measurement (like a 1/3 octave real-time-analyzer) does not agree with the subjective impression, which is dominated by first-arrival sounds. (Get the first-arrival spectra flat, and the rest falls in line. If the first-arrival spectra is not flat, the speaker will not sound flat, regardless of what the RTA is measuring. This, by the way, is where auto-EQ home theater systems fall down.)
What makes the first three reflections problematic is they originate at emission angles from the loudspeaker that are severely off-axis, nowhere close to the idealized 60-degree-wide lateral "listening window". The floor bounce isn't too bad, but the rear-wall reflection and the sidewall reflection are emitted way, way off-axis, at emission angles that aren't even measured with most loudspeakers.
With a point-source loudspeaker, combing effects from these early reflections will be severe, with very deep nulls. With a larger emitter, the reflections have more time-blurring, as well as greater spatial extent, so the nulls are not nearly as deep. (Pretend the walls are mirrors, and you can actually see the back and side of the loudspeaker in the reflections. The point-source loudspeaker is like a bare light bulb, while the bigger speaker is more like a diffuse source.)
This is one way the ear can easily distinguish between small and large emitters; the summation from the early reflections is quite different between a point-source and a larger emitter. It is worth keeping in mind many (acoustic) musical instruments have a relatively large emission surface compared to loudspeakers, and we have an unconscious expectation what instruments should sound like in a listening room. Anyone that's ever heard a piano in a recital room isn't going to be fooled by the sound of mini-monitor in the same room. Even when played quietly, a concert-grand piano has a room-filling sound that is big and powerful; by comparison, a mini-monitor sounds like a headphone sitting on a table.
These three reflections are the first to arrive in most listening rooms, and the ear gives strong preference to these earliest arriving sounds. The ear's preference for first-arriving sounds is why a time-averaging microphone measurement (like a 1/3 octave real-time-analyzer) does not agree with the subjective impression, which is dominated by first-arrival sounds. (Get the first-arrival spectra flat, and the rest falls in line. If the first-arrival spectra is not flat, the speaker will not sound flat, regardless of what the RTA is measuring. This, by the way, is where auto-EQ home theater systems fall down.)
What makes the first three reflections problematic is they originate at emission angles from the loudspeaker that are severely off-axis, nowhere close to the idealized 60-degree-wide lateral "listening window". The floor bounce isn't too bad, but the rear-wall reflection and the sidewall reflection are emitted way, way off-axis, at emission angles that aren't even measured with most loudspeakers.
With a point-source loudspeaker, combing effects from these early reflections will be severe, with very deep nulls. With a larger emitter, the reflections have more time-blurring, as well as greater spatial extent, so the nulls are not nearly as deep. (Pretend the walls are mirrors, and you can actually see the back and side of the loudspeaker in the reflections. The point-source loudspeaker is like a bare light bulb, while the bigger speaker is more like a diffuse source.)
This is one way the ear can easily distinguish between small and large emitters; the summation from the early reflections is quite different between a point-source and a larger emitter. It is worth keeping in mind many (acoustic) musical instruments have a relatively large emission surface compared to loudspeakers, and we have an unconscious expectation what instruments should sound like in a listening room. Anyone that's ever heard a piano in a recital room isn't going to be fooled by the sound of mini-monitor in the same room. Even when played quietly, a concert-grand piano has a room-filling sound that is big and powerful; by comparison, a mini-monitor sounds like a headphone sitting on a table.
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Hey,
Let´s get back on the LeCleach track again. Recently received a batch of 16 horns from Jack and Lukasz. We still haven´t installed them just done some simple measurements with JBL2441.
Note the 150Hz Tractrix horn up in the right corner. Also the 2441 looks really tiny below.
Simple measurement on axis:
My friend hoktuna showing up one of his new babies.
Let´s get back on the LeCleach track again. Recently received a batch of 16 horns from Jack and Lukasz. We still haven´t installed them just done some simple measurements with JBL2441.
Note the 150Hz Tractrix horn up in the right corner. Also the 2441 looks really tiny below.
Simple measurement on axis:
My friend hoktuna showing up one of his new babies.
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Back loaded horn discussion split to here: http://www.diyaudio.com/forums/multi-way/182233-back-loaded-horns.html
Stunning flatness in the midrange. What smoothing is used?
What I miss with this measurements is distance and position microphone MLS window length used filter. Then it becomes possible to say some thing about the result.
What I miss with this measurements is distance and position microphone MLS window length used filter. Then it becomes possible to say some thing about the result.
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A question what is a course measurement or is your English is bad as mine and is it a wrong word.
I believe the correct word would be coarse(Coarse - Definition and More from the Free Merriam-Webster Dictionary).
Frode
Helmuth,
You must have understood what was ment, so why be picky wrt spelling? Bother about loudspeakers instead! From what I have read, my spelling is in no way as bad as yours😉.
Until now this thread has been friendly and polite so let this be a parenthesis, ending now.
About speakers I am at the moment working on a midbass "Hornreflex", see VOTT or 816, with the horn being LeCleach.
Using my Altec 414-8As in 1*Pi(on floor, against sidewall) it will only be ca 120dm3. It's a compromise but the only way to make this speaker work in a horn.
Will do the testruns with two Tractrix 150Hz that, at the moment, is stashed in my garage(you can see one in the upper right corner of the "garage midhorn" pic). Box is ca 60dm3.
Will crossover at, in the ballpark of, 350Hz.
You must have understood what was ment, so why be picky wrt spelling? Bother about loudspeakers instead! From what I have read, my spelling is in no way as bad as yours😉.
Until now this thread has been friendly and polite so let this be a parenthesis, ending now.
About speakers I am at the moment working on a midbass "Hornreflex", see VOTT or 816, with the horn being LeCleach.
Using my Altec 414-8As in 1*Pi(on floor, against sidewall) it will only be ca 120dm3. It's a compromise but the only way to make this speaker work in a horn.
Will do the testruns with two Tractrix 150Hz that, at the moment, is stashed in my garage(you can see one in the upper right corner of the "garage midhorn" pic). Box is ca 60dm3.
Will crossover at, in the ballpark of, 350Hz.
Which horn?
Which size horn? Is that the Autotech 200T? It looks from the measurements that they made the perfect fit on both ends of the adapter as there is no sign in the frequency response of any disturbance of the wave expansion. The seam at the additional flair back piece is perfect also. That would be a nice horn for the dual voice coil BMS driver. What bass drivers will be able to keep up with that?
.
Which size horn? Is that the Autotech 200T? It looks from the measurements that they made the perfect fit on both ends of the adapter as there is no sign in the frequency response of any disturbance of the wave expansion. The seam at the additional flair back piece is perfect also. That would be a nice horn for the dual voice coil BMS driver. What bass drivers will be able to keep up with that?
.
Hey,
Let´s get back on the LeCleach track again. Recently received a batch of 16 horns from Jack and Lukasz. We still haven´t installed them just done some simple measurements with JBL2441.
Note the 150Hz Tractrix horn up in the right corner. Also the 2441 looks really tiny below.
Simple measurement on axis:
My friend hoktuna showing up one of his new babies.
hi Lars
i have a similar solution as yours, using in my 38" / 96cm tractrix midbass horn a Radian 950pb 2". In my books, drive it down to 150hz is too low. The driver will not handle it properly, you'll have not enough output. Your horn is even shorter than mine. The best result, i got, is using it above 300hz/6db.
Angelo
i have a similar solution as yours, using in my 38" / 96cm tractrix midbass horn a Radian 950pb 2". In my books, drive it down to 150hz is too low. The driver will not handle it properly, you'll have not enough output. Your horn is even shorter than mine. The best result, i got, is using it above 300hz/6db.
Angelo
As I understand Lars, the 150Hz Tractrix goes in front of the Altec 414, and the new Autotech horn will only be used above 350Hz.
Frode
It was a serious question about the word and I made a yoke about my own bad English.
So do not misunderstand me, when I try to understand your answer.
Hey sendler,
This a 200Hz horn custom made for us. It is for 2" OS JBL like 2441, 2482 etc. Will try the 2441 cut at 350Hz. It will probably work at the low levels at home. Otherwise I´ll go for the 2482.
Frode,
You are so right, the short horn(ballpark figures, L=35cm, At=400cm2, Am=3600cm2) will be in the front of the 414 and the bassreflex at the rear. Hopefully the transition at 350Hz will work. Asked Jean-Michel and he told me one could cut the 200Hz-horn well below 400Hz.
Helmuth,
I apologize for being grumpy. I´m just having a bad day at work😱.
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Revintage. That's a mighty good looking horn and FR plot you've got going there. The waterfall looks very good, too. Sure, there is a 5dB rise thru the midrange, but it's wide and smooth, quite remarkable.
I'm looking forward to seeing more if you get the chance. Phase/Group delay, and H2, H3 distortion should also look very good.
Were they made by Zagaja in Poland?
I'm looking forward to seeing more if you get the chance. Phase/Group delay, and H2, H3 distortion should also look very good.
Were they made by Zagaja in Poland?