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I`d like to know what the forum gurus feel would be the optimal horn type ( preferably spherical ) that would be best suited for use in the
frequency range of 70 hz to 800 hz using the Ale P1260 mid low driver.
Apparently, tractrix is not ideal below a mouth circumfrence of approximately 88 cm ( more or less 100 hz ) and rectangular horns aren`t best suited for use above 250 hz. Would a spherical exponential horn work here or is there another solution ? Thanks...
Dan
Follow Ups:
zzz
Hello,
70Hz to 800Hz is more than a decade. That's a very difficult task for any horn to cover such a large interval of frequency
Even the Ale Horn reference EX70 covers only the interval 100Hz to 500Hz
http://www.tachyon.co.jp/~sichoya2/ale/horns.html
Most "snail horns" cannot cover a decade the only exception being the WE15A :
http://www.audioanthology.com/building.htm
and its variations like the WE22A: http://members.jcom.home.ne.jp/atrc/page026.html
(unfortunately the WE22A must be cut at 150Hz or 200Hz min). This feature on WE horns is due to an equilibrium between pure horn loading at low frequency and reflections of waves on the outer wall at high frequency. This was obtained by an emprirical but clever balance between curvature radius and thickness/width ratio of the sections in the curved part of the horn. Unfortunately Ale curved horns don't use sections having a large ratio width/thickness in their curved part and they cannot be used over a large interval of frequency.
If you cannot afford a WE15A, better to use a straight horn to cover such large interval of frequency.
Conventionally, if you want to cut electrically at 80Hz you should use a 40Hz maximum acoustical cut-off but at low frequency we are less sensitive to phase ditortion (or more accustomed to, eg. bass-reflex...)so IMHO it is not necessary and you may use a horn with a 80Hz cut-off.
It will be also interesting to play with reactance annulling at throat but this is not easy when using a compression driver.
Then, if you want to avoid any resonance (tuned pipe effect), you have to use a quasi infinite horn, this means a mouth opening at 180 degres minnimum and the dimensions will be large. (horns having a "cut mouth" tend to have a recognizable "horn sound" and cannot be used over a large interval of frequency with good results: eg: Goto and Ale straight horns).
For any Tractrix, Kugelwellen or for a horn having a profile calculated by my method (horn having a 80Hz cut-off and calculated for a 75mm throat), the outer diameters will range between 1,8 meter (71 inches) to 2,6 meter (102 inches) and the length between 1,9 (75 inches) to 2 meter (80 inches).
Best regards from Paris,
Jean-Michel Le Cléac'h
bonjour Jean Michel
can you explain me why Avantgarde and others do use a > 50cm diameter midrange Horn above their 95cm diameter mid-bass horn, if it does only have to cover > 500hz, and theoretically only a 20cm diameter horn would be needed ?
rds Angelo
Hello,
There is several possible answers to that question but here the most logical:
- in order to operate the horn inside a frequency range for which the acoustical impedance of the horn is mainly resistive (and not reactive in order to avoid phase distortion) we have to use a high pass frequency an octave minimum above the acoustical cut-off frequency of the horn. This means that for a tractrix horn used above 500Hz, the acoustical cut-off should be 250Hz. If we consider a complete tractrix horn opening at 180 degrees this means a horn having a 433 millimeters diameter.
Please notice: classical empirical formulas giving relations between cut-off frequency and diameter give a minimum diameter. IMHO thet can be useful in the pro domain where a smaller volume is desired. In the hifi domain they should be avoided.
Martin Seddon in Australia and Marco Henry here in France did listening tests on horns calculated with my method and having cut-off frequency around 160Hz. There conclusion are similar: a JMLC round horn with a profile opening at 360degrees is better than a JMLC horn opening at 180 degrees.
For horns: larger is better!
Best regards from Paris.
Jean-Michel Le Cléac'h
Jean -Michel,
Thanks for taking the time to respond with such clear understanding of
the subject as well as the courtesy expressed.
Dan
Hi Jean-Michel
so this would apply also for 88cm mid-bass horn? Meens if acoustical cut-off of the horn is 125hz, the upper bass driver would have to be low pass at 250hz ?
Angelo
Hello,
That's right.
The only exception is if you process the signal sent to the loudspeakerwith a DSP in order to obtain a linear phase signal at the mouth .
Best regards from Paris,
Jean-Michel Le Cléac'h
Why do you think a spherical horn is to be preferred? Beyond Hasquin, is it an aesthetic issue?
What will you use below your 70hz cutoff, and what above?
How large is your listening space? How do you listen? Some want to be dead on axis, some do not.
Without such information I can't imagine any useful advice. You have a driver that is very specific, very atypical in its application. My understanding is that people who own such Goto or ALE drivers own their siblings, and use them in a nuclear family.
It is definitely THE approach to the passband, probably why Romy hates you.
Jonathan
Greetings, Dan...
you have gotten some good advice and some rotten... you really should talk to Kevin Brooks on this... I have hard these drivers at his place... sounded very good...
what you need is length.. that is what 99% of the horns in this frequency range will be short of (ha!).... Hasquin was not dealing with compression drivers, so his horns were shorter... you can use tractrix in this range... round or rectangular (use 1:1.6)... your horn will have to be long due to the small throat of your driver... the catch is that longer horns don't sound as good on the higher end.... but I think what you want is just a glorious ~100 to ~600... and for that I think you have the perfect driver.... and the throat size will dictate that almost any 75Hz horn will deliver exactly what you want...
I don't think that the shape is all that important for the center seat... many shapes can sound wonderful... but, I would try for round.... it will be big, though... perhaps an eleven sided petal horn like the German Goto users would be best....
I have played with quite a few drivers in this range... and they have all been good... horns just rule the midbass... I am working with Ming Su, the US Goto distributor, on a few things and I am very excited that this technology is attracting more followers... the Asylum regulars from Cogent are also building incredible midbass compression drivers... a new golden age? I doubt it, but I sure am glad to have these things around!
Peace,
Me
Hi Me,
Thanks for re-enforcing the notions I`ve had as far as these drivers go.
Yes, the horns are big but in theory they should really produce if properly implemented. That`s why I was preoccupied with making a wrong
turn with regards to horn type. I also much prefer the round configuration. Do you feel that the Ale middle low driver can do 70 hz to 600 hz as well as any of the others you`ve worked with ?
I will certainly speak to the distributers you mention for more particulars. Much appreciated.
Dan
Hi Dan,
You need to talk to Kevin regarding the best application of your ALE driver.
I can share with you my GOTO setup. I use twin GOTO SG146LD4 compression bass driver with Y-throat adapter mounted to a 1:2 ratio rectangular horn. By using twin driver per channel, it shorten the horn length by about 73 cm. If you use 4 driver per channel, you can reduce even more. Due to the size of my listen room, I have to limit the horn to cutoff at 60Hz and crossover at 70Hz. The top end will be limited at 400Hz. Everything above 400Hz will use GOTO round hyperbolic horn. The 70Hz down will use GOTO 15" driver in bass reflex cabinet. GOTO provides round hyperbolic horn for cutoff freq. of 150Hz, 200Hz, 300Hz, 600Hz and 800Hz. The 3000Hz horn come with GOTO tweeter.
Hope this help,
Ming
Hi Ming,
Sounds like you have quite a wonderful system going there.
What are your observations WRT time alignment in the 70-400Hz range?
Do you use digital delay, and if so how does it work for you?
Also interesting how you can shorten the horns by adding drivers.
Could be a little expensive right :-)
That 70-150 range is a real bear to deal with.
Take care,
Mats
Mats,
My bass horn won't be ready until end of July. By then, I will deal with the time alignment issue, however, since the horn length is just 102", the issue should be min. I am using active crossover and can deal with that in that domain if needed.
Ming,
So you are already getting "Goto-quality" filtering in the digital domain?
Do you care to elaborate? I have a DCX2496 that Jeffrey Jackson tweaked, waiting for the right project.
102" is not bad at all. Is it a J-horn? How big is the mouth? Late July arrival eh? Please share pictures!
Mats
NO. I will have to wait until the bass horn is ready and all the other driver in place to deal with time issue. According to other GOTO user, there is no problem to deal with that. Some use digital domain to adjust but most do not have to do any.
All horns are straight horn including the bass horn. GOTO insists on using only straight horn for all their driver.
Sure, I will post sme pictures once the system is ready.
has been shown on the web many times. The bass horn is rectangular with a 3' x 4' mouth and about 17ft long or so. IIRC, it is an elliptical expansion and will respond to about 70hz.
As much as I love Azura horns, they will not allow this driver to respond below 150-200hz.
Josh has built horns for this ALE driver also. His were not rectangular, but I could not characterize the shape exactly. :) He used more of a tractrix expansion for his, so they were shorter than Kevin's, and they had a long sweeping tail on them...reminescent of the old WE horns. He has also built some that hybridized tractrix and conical expansions for midrange and HF, that sounded pretty good.
It is critical to get the length and mouth size correct in order to fully optimize this driver's capabilities. But when you do.....Oh baby....:)
He is now finishing up horns for some Cogent drivers that are pretty nice. You can contact him at electronluv.com for information and advise about utilizing this driver.
See you later
D
Altec A-7 cabinet would fit your needs.
Sorry, I should of indicated I was looking strictly for a horn solution.
Thanks..
Dan
Sorry once again, A compression driver horn solution. Thanks...
Dan
Azurahorn is an option, but I think the Le Cléac’h flare rate gives you a longer horn than a Tactrix flare rate and at 200hz you already have quite a long horn.
You can do a fast calculation of the lenght for a 100hz horn and a 75mm thoat compression driver and see if you can fit it properly in your set-up.
If not you would have to bend it, and I wouldnt know how good that would be....
For that driver I would go all out and get a Western Electric snail horn!
You would probably have to make a complete room for your system...
Hi Saturntube,
Thanks for your suggestions. Yes, I realize it`s a huge horn. I plan to
have an mdf straight horn made for the Ale driver which will have a
dedicated listening room built around it.I just can`t determine which is
the best horn option to use. Thanks again.
Dan
So it is a straight MDF horn for the ALE P1260 driver with a 75mm throat:
The Tactrix flare rate is the shortest one so you can play around with this page untill you reach a compromise on size vs lowest freq.
http://melhuish.org/audio/tractrixcalc.html
The main problem will be to time align the driver with the next 800hz driver.
"Apparently, tractrix is not ideal below a mouth circumfrence of approximately 88 cm ( more or less 100 hz )"
I think you are refering to the John Hasquin quote:
" I would advise you not to make a horn any bigger than 88cm mouth. The 95cm mouth horn is too big and you will not be able to get good high frequency out of it. A 95cm mouth horn with 10cm throat will be about 92cm deep. For a horn that is between 80cm to 73cm deep, you will need a very efficient speaker like the Fane Studio 8M or the Ciare 8.5 Nd MR "
I think he meant this for a horn coupled to a normal 8" speaker like the Studio 8m or say a Lowther speaker (for comparison purposes only). With a specialized compression driver like the ALE P1260 you can almost use any size and lenght horn you wish...
Dont go for a terribly long horn I think time alignment is key here...
Or you can just forget about time alignment and get any lenght horn and see how it sounds....
Yes, you`ve hit the nail on the head. I had read John Hasquin`s comment`s
which really set me to wondering if I was considering something fundamentally wrong by choosing a spherical tractrix or exponential horn
for the 70hz to 800hz range. If you`re right that John was refering to a cone driver in his comments then that would certainly simplify the issue.
Time alignment won`t be problem as I will use an active amp and crossover setup with will permit electrical alignment.
You`re response has been very much appreciated.
Dan
Ciare 8.5 Nd MR
http://www.assistanceaudio.com/08_CIARE.html
http://www.ciare.com/oem_new/index.html
Do send us pics of your setup when its finished!
All the best
Many thanks Saturntube...NT
hi ogimathis driver is a sub basshorn driver, lowpass crossover should not be higher than 100hz. ( ideal is 50 - 60hz ) The best is to use a original ALE basshorn, ore one made on specifications similar as this one. This are the ALE original Horns for this driver :
http://www.flickr.com/photos/audiovoice_hornloudspeakers/472612604/
http://www.flickr.com/photos/audiovoice_hornloudspeakers/472612596/here the plans for diy :
http://www.flickr.com/photos/audiovoice_hornloudspeakers/472616177/
i heard this basshorn with your driver in japan :
http://www.flickr.com/photos/audiovoice_hornloudspeakers/472604712/
and even with the driver electronically time aligned, i heard clearly that the sound was coming from a long distance in front of me ( 12m )
i recommend you to high pass it at 20hz, otherwise it will blow easily. Jean Yves Kerbrat wich uses this drivers blow it , at to get replacement diaphrama in japan is not a easy task, and expensive.
I do not recommend this sub basshorn solution. It looks impressive, but the obtainable result is questionable. Mr. Marcel Roggero uses 12 Altec 515-8GHP ( 6 per side ) in his basshorn, and gets a clean 18hz.
http://audiyofan.org/forum/viewtopic.php?t=5555&sid=6b43b905f198494403fad4d013512d50
People in france who heard it say it is much better than the system from Jean Yves Kerbrat
http://www.flickr.com/photos/audiovoice_hornloudspeakers/495469539/
rds Angelo
Hi Angelo,
Thank you for your response. However, my intention is not to use the
P 1260 in a sub bass application as it is a middle low frequency driver
which Ale recommends in the frequency range of 70 hz to as high as 800 hz. Are you saying that you did not like the Ale sound from your audition experience in Japan due to the horn length or because of the Ale tone. A 70 hz to 800 hz horn is not really all that long ( much shorter then a sub bass horn by far ) and should be easily time aligned electronically. But if the tone was not pleasing that`s a whole other
thing. Did you listen to the Goto drivers while you were over in Japan ? If you did,what was your impression ? Thanks...
Dan
hi Dan
for this driver you can see the japanese tachion site :
http://www.tachyon.co.jp/~sichoya2/ale/horns.html
here pictures of horns that may would work, however without specs to diy, but you get a idea :
http://www.flickr.com/photos/8010632@N05/497346407/
http://www.flickr.com/photos/audiovoice_hornloudspeakers/495469549/
http://www.flickr.com/photos/audiovoice_hornloudspeakers/497119051/
http://www.flickr.com/photos/audiovoice_hornloudspeakers/497119057/
ore this Audio Note Mid-Bass Horn specification sheet, witch probably would work fine for your driver too, so you can diy:
http://www.flickr.com/photos/audiovoice_hornloudspeakers/472612411/
i did not hear goto drivers yet, only ALE drivers and Audio Note drivers ( formet YL ) with silver diaphragmas, at Kondo San's factory. Mid Bass of his system was effortless, transparent, dinamic, and somehow soft sounding and warm. I did like it.
rds Angelo
Ok Angelo,
I will look over all the info you`ve sent. I`m glad to hear you liked the Ale mid bass. Good luck with all your speaker development projects...
they look very nice. BTW, Romy the Cat shut me out of his site because he somehow got it in his head that I was you. Strange,strange fellow.
Dan
hi Dan
he excluded me and start to hate me because was not able to handle emotionally when i spoke clear text abought his behavior in this thread :
do u really need this kind of language ?
http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=3869#3869
Angelo
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