Hi GM, hi everyone,
I found an interesting project on LS3/5a French forum. This project is made with a GPA 414-8B and a cab of the right size (around 105 L) like GM calculated. It has a TD2001 above with a special horn, the JBL 2301. The cross-over point is around 1500 Hz.
The discussion is in French but you can catch the idea of the project. The author already complete it and the sonic result seems fantastic, nothing less:
Nouveau projet de GB Product La LS 35 . • LS3/5a le forum
Have a good week-end,
Sébastien
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1500 hz wowwwwwww ! Bonjour la directivité et le medium decharné... malgré ce bon Altec et le volume de la charge correct pour les basses ! (message perso Sebastien with no offense - d'ailleurs le prochain qui me dit en anglais ici j'ecris javanais )And what about the JBL horn above... ring like a bell !
People have already try all those since 40 years with these altec driver... As you speak french, give yourself a gift before wasting to much money (but if you have it or already the drivers
: Elektor "Bien entendu, itineraire d'un audiophile" de Francis Ibre : it talks about all the design he tested in his life with high efficienty and CD, horns, bass cabinet... I'm not a Melaudia association fellow but I'm sure you will find better advice (or here of course) than the link you gave.All is not good but many many good testimonies and practice designs in this book, a very good first part about the listening space !
Good luck Sebastien...
Good luck Sebastien... echo of the JBL horn....
And what about the JBL horn above... ring like a bell !
People have already try all those since 40 years with these altec driver... As you speak french, give yourself a gift before wasting to much money (but if you have it or already the drivers
All is not good but many many good testimonies and practice designs in this book, a very good first part about the listening space !
Good luck Sebastien...
Good luck Sebastien... echo of the JBL horn....
Bonjour Eldam, hi everyone,
Yes, as GM calculated, the volume of the cab is the right one for the new GPA 414-8B. That's interesting for me as I'd like to have a plan already calculated and draw.
I have Francis Ibre's book and I'm actually re-reading the section on the speakers. I know what you mean regarding directivity. That is my main concern. I exchange some emails with Francis in the last two week regarding which driver could be cut around 800 Hz and what to expect. Francis talk to me about this importance.
I ask the LS35 designer about it and he told me that the directivity is "correct".
With your post, Francis' opinion, GM calculation, I start to tell me that the best idea could be to re-draw the petite Onken to have it at 105 L, stretch my budget and get the famous TAD TD2001. Well... still thinking.
Bonne journée,
Sébastien
Bonjour Eldam
Pour le bas médium , celui que je préfère c'est avec le Coral Beta 8 ( en direct large bande et un sub par dessus pour certaine musique seulement ) .... plein de détail , très musical , que j'ai jamais retrouver sur un autre driver . Il me reste à faire une comparaison avec une driver 2" qui descendrait jusqu'à 200 hz ( horn de 1 M )
Eldam , Sébastien est relativement nouveau dans ce domaine ..... il n'a pas beaucoup d'expérience personnel , donc il se fit a celui qui a une bonne renommé ..... c'est un début .
GOOGLE TRANSLATE ;
For the lower midrange, the one I prefer is the Coral Beta 8 ( in Full Range and sub over for some music only) .... full of detail, very musical, I have never found another driver with there musicality. It remains for me to make a comparison with a 2 "driver that descend to 200 hz (horn 1 M)
Pour le bas médium , celui que je préfère c'est avec le Coral Beta 8 ( en direct large bande et un sub par dessus pour certaine musique seulement ) .... plein de détail , très musical , que j'ai jamais retrouver sur un autre driver . Il me reste à faire une comparaison avec une driver 2" qui descendrait jusqu'à 200 hz ( horn de 1 M )
Eldam , Sébastien est relativement nouveau dans ce domaine ..... il n'a pas beaucoup d'expérience personnel , donc il se fit a celui qui a une bonne renommé ..... c'est un début .
GOOGLE TRANSLATE ;
For the lower midrange, the one I prefer is the Coral Beta 8 ( in Full Range and sub over for some music only) .... full of detail, very musical, I have never found another driver with there musicality. It remains for me to make a comparison with a 2 "driver that descend to 200 hz (horn 1 M)
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Eldam, 4mc2,
Even if I understand that French is your first language, like me, and you and I love it, we should discuss in English here on DIYaudio. DIYaudio is international and and it's a principle of inclusion to use this language. I don't know about forum rules, but that's my opinion. I want everyone to be included in the discussion.
Thanks,
Sébastien
Even if I understand that French is your first language, like me, and you and I love it, we should discuss in English here on DIYaudio. DIYaudio is international and and it's a principle of inclusion to use this language. I don't know about forum rules, but that's my opinion. I want everyone to be included in the discussion.
Thanks,
Sébastien
Sebastien,
I think french was used only for you like gentle "fathers or big brothers" to say you that you way was wrong (just a part of it) with no offense. With all due of respect to all the others fellows of course !
Some though, maybe it can help you :
You know nothing about the measurements of the french fellow : there are some funy one with greaty personal web site who develop sheet during all their life ! It's nearer sometimes to a mirror than a speaker !
Mister Ibre doesn't save time to help everybody at elektor forum : great experience, you can trust him.
TDA2001 : I will save for the older brother instead; but you have many less expensive driver almost as good. Horn is important : choose someting between Iwata, constant directivity, heavy wood if you can (damping is important). Some very short circular horn à la Geedle woerth a try. But here sources are few at ridiculous price (around 200 dollars for plastic !).
Try to avoid 2 ways
, saving the cost of great driver in two ways to go to 3 ways will give the best result. You have a very good driver with the Altec Clone Already. Go absolutely with active filtering with te saved money : here there is a brand than even the best designer here use: minidsp +curryman dac are great bargain : if I need to go active for the best bargain I will choose this way myself !
try to think something around this : Onken : try not to go more than 300 hz. 100 to 150 hz is ideal but harder to cross.
Medium : take a look at Aunio Gradient thread from Juhazi fellow here : a 10" Beyma in open bafle without bafle or a Faital Pro or other more expensive maid in America like the one with the big bullet for directivity (search mode!) : try to cross between 1000 to 1800. No box, money saved but don't use if you room is small or Onken near the front wall...
then a lot of inexpensive good modern CD which works perfect between around 1000 hz to the end ! Do your market here, a lot of fantastic fellows tried almots all here at DIYA ! Thinking about the Heil clone TPL Beyma tweeter is maybe a good idea : with a short horn (some adress here) you can beginn around 1500 hz with the high efficienty way you choosed !
It is just a global road map, good designers can do different but here for beginners like us, I think risks are softed with such design and money saved. The best shrimps with a bad cookers smell like bad fish !
I'm not agree with F Ibre about the 8" for mid if paper but with surface added materials (the problem with paper is the lake of definition according to me, but it's hard to be avoid if high efficienty is needed.... make your choice !).
Just two cents
I think french was used only for you like gentle "fathers or big brothers" to say you that you way was wrong (just a part of it) with no offense. With all due of respect to all the others fellows of course !
Some though, maybe it can help you :
You know nothing about the measurements of the french fellow : there are some funy one with greaty personal web site who develop sheet during all their life ! It's nearer sometimes to a mirror than a speaker !
Mister Ibre doesn't save time to help everybody at elektor forum : great experience, you can trust him.
TDA2001 : I will save for the older brother instead; but you have many less expensive driver almost as good. Horn is important : choose someting between Iwata, constant directivity, heavy wood if you can (damping is important). Some very short circular horn à la Geedle woerth a try. But here sources are few at ridiculous price (around 200 dollars for plastic !).
Try to avoid 2 ways
, saving the cost of great driver in two ways to go to 3 ways will give the best result. You have a very good driver with the Altec Clone Already. Go absolutely with active filtering with te saved money : here there is a brand than even the best designer here use: minidsp +curryman dac are great bargain : if I need to go active for the best bargain I will choose this way myself !try to think something around this : Onken : try not to go more than 300 hz. 100 to 150 hz is ideal but harder to cross.
Medium : take a look at Aunio Gradient thread from Juhazi fellow here : a 10" Beyma in open bafle without bafle or a Faital Pro or other more expensive maid in America like the one with the big bullet for directivity (search mode!) : try to cross between 1000 to 1800. No box, money saved but don't use if you room is small or Onken near the front wall...
then a lot of inexpensive good modern CD which works perfect between around 1000 hz to the end ! Do your market here, a lot of fantastic fellows tried almots all here at DIYA ! Thinking about the Heil clone TPL Beyma tweeter is maybe a good idea : with a short horn (some adress here) you can beginn around 1500 hz with the high efficienty way you choosed !
It is just a global road map, good designers can do different but here for beginners like us, I think risks are softed with such design and money saved. The best shrimps with a bad cookers smell like bad fish !
I'm not agree with F Ibre about the 8" for mid if paper but with surface added materials (the problem with paper is the lake of definition according to me, but it's hard to be avoid if high efficienty is needed.... make your choice !).
Just two cents
Just so we’re on the same ‘page’, this is based solely on published specs, so may not be optimum with your drivers, so leaving it a little large for some tuning flexibility seems a good plan.
Also, I see you plan to ultimately drive this with a very high output impedance SE amp, which will raise the effective Qes, Qts considerably and since Hiraga’s simple formula assumes a very low total output impedance [amp+wire+XO series resistance = < ~ 1 ohm], you will get a technically poor driver, cab alignment [and audibly, for some folks].
At this point then, building, or even ‘shrinking’, such a relative ‘inflexible’ cab alignment seems to be a bad plan over the long term IF maintaining Hiraga’s intended cab loading performance is one of your primary performance goals; otherwise, to maintain the Onken alignment it’s best overall to design a k = 1.57 Onken using the full set of specs that factors in the effective Qts, which in turn will mean a much larger cab for the SE amp.
GM
Also, I see you plan to ultimately drive this with a very high output impedance SE amp, which will raise the effective Qes, Qts considerably and since Hiraga’s simple formula assumes a very low total output impedance [amp+wire+XO series resistance = < ~ 1 ohm], you will get a technically poor driver, cab alignment [and audibly, for some folks].
At this point then, building, or even ‘shrinking’, such a relative ‘inflexible’ cab alignment seems to be a bad plan over the long term IF maintaining Hiraga’s intended cab loading performance is one of your primary performance goals; otherwise, to maintain the Onken alignment it’s best overall to design a k = 1.57 Onken using the full set of specs that factors in the effective Qts, which in turn will mean a much larger cab for the SE amp.
GM
Sebastien,
I think french was used only for you like gentle "fathers or big brothers" to say you that you way was wrong (just a part of it) with no offense. With all due of respect to all the others fellows of course !
Some though, maybe it can help you :
Hi Eldam,
Ok, I understand, but I never took anything as an offense and I appreciate your tought. Like I said, with GM's feed-back, yours, Francis Ibre's, it greatly help my reflexion.
For you information, and because your talking open baffle, the first designed that capted my attention for a clone recently was the Yamamoto YS-500, a semi open baffle. Then, my path took me to the Onken family.
Sébastien
Hi GM,
I understand you tought about the PSE 300B impedance. With my mono-blocs, we should be around 2 Ohms, 1 Ohm is even worst
, that's Pieter from Tribute who told me the 2 Ohms measure. My OPT are from him.Then, I'm not sure if I understand you clearly, what do you suggest? Do you suggest in that case to keep it to the original 155 L design for a better association with my PSE 300B?
Thanks for your help,
Sébastien
I love GPA's alnico ("Classic Series") woofers, but I most definitely agree that it would be a mistake to rely on the published specs.
I have GPA 416-8B's and 515-16C's. Measurements of both showed significant deviation from those shown on the data sheets. I also had a pair of 414-8B's, but I sold them to a friend. He went ahead and tested them -- it would be interesting to find out how closely they match the data sheets.
My recommendation would be the same when using vintage Altec woofers: first measure, then design the enclosure.
I can't say enough good things about the GPA 416-8B's, by the way. They sound wonderful!
Gary Dahl
I have GPA 416-8B's and 515-16C's. Measurements of both showed significant deviation from those shown on the data sheets. I also had a pair of 414-8B's, but I sold them to a friend. He went ahead and tested them -- it would be interesting to find out how closely they match the data sheets.
My recommendation would be the same when using vintage Altec woofers: first measure, then design the enclosure.
I can't say enough good things about the GPA 416-8B's, by the way. They sound wonderful!
Gary Dahl
Greets!
Originally, I suggested leaving it at 155 L because the drivers you buy may have different specs and way more often than not this dictates a larger cab tuned lower to maintain a similar/same overall response slope cab alignment.
For instance, another original 414-8B’s specs would need to be ~221.5 L/~35 Hz Fb using Hiraga’s math, so between Hiraga’s driver and this other one it’s obvious that like most [all?] manufacturers, Altec played ‘fast and loose’ over time WRT what it built to keep up with the rapidly changing ‘world’ of electronics that had amp damping factors [DF] zooming up [eventually spiraling down output impedance into tiny fractions of an ohm], which required the driver+cab alignment to become the primary source of damping.
Don’t know what you mean by 1 ohm being worse than 2 ohm since the higher the resistance the more under-damped [‘loose’/’boomy’] the cab alignment becomes and why doing a proper Onken seems the way to go if an Onken is what you want, i.e. there’s nothing special about Hiraga’s alignment and arguably a poor choice overall in many [most?] apps since it doesn’t take the driver’s effective damping [Qts] into account, not to mention that to get the max bass efficiency with a high output impedance requires the cab be accurately tuned to the driver’s Fs.
Anyway, IF GPA builds yours to spec, then using an Onken calculator and adding 2 ohms of amp resistance and a ½ ohm of wiring resistance ideally requires a 180.8 L/34 Hz Fb.
To the first approximation then, ‘critically’ damping the 155 L’s vents in room should do just fine. Ideally you would do this with an impulse response, but normally just finding the point by ear where it sounds ‘tight’ and any more damping just obviously is rolling off the bass is sufficient, just be sure that the HF is disconnected during the tests.
If I use the older 414-8B’s specs though, it zooms up to 394.41 L/23.15 Hz!
In 155 L then, it will need to be either heavily stuffed [~aperiodically damped] or sealed.
GM
Originally, I suggested leaving it at 155 L because the drivers you buy may have different specs and way more often than not this dictates a larger cab tuned lower to maintain a similar/same overall response slope cab alignment.
For instance, another original 414-8B’s specs would need to be ~221.5 L/~35 Hz Fb using Hiraga’s math, so between Hiraga’s driver and this other one it’s obvious that like most [all?] manufacturers, Altec played ‘fast and loose’ over time WRT what it built to keep up with the rapidly changing ‘world’ of electronics that had amp damping factors [DF] zooming up [eventually spiraling down output impedance into tiny fractions of an ohm], which required the driver+cab alignment to become the primary source of damping.
Don’t know what you mean by 1 ohm being worse than 2 ohm since the higher the resistance the more under-damped [‘loose’/’boomy’] the cab alignment becomes and why doing a proper Onken seems the way to go if an Onken is what you want, i.e. there’s nothing special about Hiraga’s alignment and arguably a poor choice overall in many [most?] apps since it doesn’t take the driver’s effective damping [Qts] into account, not to mention that to get the max bass efficiency with a high output impedance requires the cab be accurately tuned to the driver’s Fs.
Anyway, IF GPA builds yours to spec, then using an Onken calculator and adding 2 ohms of amp resistance and a ½ ohm of wiring resistance ideally requires a 180.8 L/34 Hz Fb.
To the first approximation then, ‘critically’ damping the 155 L’s vents in room should do just fine. Ideally you would do this with an impulse response, but normally just finding the point by ear where it sounds ‘tight’ and any more damping just obviously is rolling off the bass is sufficient, just be sure that the HF is disconnected during the tests.
If I use the older 414-8B’s specs though, it zooms up to 394.41 L/23.15 Hz!
In 155 L then, it will need to be either heavily stuffed [~aperiodically damped] or sealed.
GM
Gary Dahl,
What do you think about all the modern production of clone like GP audio ? Are the magnet with alnico magnetized enough near the spec genuine brands used to have ?
4M2C had a good input about the Corel, but such driver is impossible to get... Is there any good high efficienty width band driver but the famous lowther or else today ? tested with ears I mean... I heared Hiraga speaker with the Great Plain Audio Altec clone... putain de bordel de Dieu... It sounds good, this man has golden ears !
Hi Gary
Google translate;
But the Full Range of today and most of the former also do not use the controlled splitting of the membrane, which makes a big difference! ..... Much more nuance.
I pretty much what Sebastian wants ...... but the coral beats without hesitation to the nuances in the medium.
" Mais les Full Range d'aujourd'hui et la plupart des anciens aussi n'utilisent pas le fractionnement controlé de la membrane , ce qui fait une grosse différence ! ..... beaucoup plus de nuance .
J'ai à peu près ( +/- ) ce que Sébastien veut faire ...... mais le Coral le bat sans hésitation pour les nuances dans le médium , mais les aigu sont moins fin "
Google translate;
But the Full Range of today and most of the former also do not use the controlled splitting of the membrane, which makes a big difference! ..... Much more nuance.
I pretty much what Sebastian wants ...... but the coral beats without hesitation to the nuances in the medium.
" Mais les Full Range d'aujourd'hui et la plupart des anciens aussi n'utilisent pas le fractionnement controlé de la membrane , ce qui fait une grosse différence ! ..... beaucoup plus de nuance .
J'ai à peu près ( +/- ) ce que Sébastien veut faire ...... mais le Coral le bat sans hésitation pour les nuances dans le médium , mais les aigu sont moins fin "
I don't consider the Great Plains Audio drivers to be clones, but rather continued production under a different name. There are some differences between old and new in certain cases, but this is no different than the situation during the Altec Lansing years, which saw a dizzying number of production changes along the way. My understanding is that the people making GPA drivers are former Altec employees, using the same equipment as they always have.
The magnets of the GPA woofers I measured were all somewhat stronger than spec, resulting in lower Qts. Also, measurements of Vas were consistently higher. These are not problems, if one accounts for these differences when designing a speaker.
I believe that the "soft parts" (cone, spider, surround) are externally sourced from the same supplier as in the past, but the newer cones aren't exactly the same as they once were. The resulting products have somewhat different t/s parameters but are excellent performers when used properly.
The drivers in the picture above (post #35) appear to be Biflex units. I have seen these but haven't ever heard them, so I don't know how they compare to Altec drivers I have used over the years. As for Coral drivers, I have heard good things about them but have no personal experiences.
Gary Dahl
The magnets of the GPA woofers I measured were all somewhat stronger than spec, resulting in lower Qts. Also, measurements of Vas were consistently higher. These are not problems, if one accounts for these differences when designing a speaker.
I believe that the "soft parts" (cone, spider, surround) are externally sourced from the same supplier as in the past, but the newer cones aren't exactly the same as they once were. The resulting products have somewhat different t/s parameters but are excellent performers when used properly.
The drivers in the picture above (post #35) appear to be Biflex units. I have seen these but haven't ever heard them, so I don't know how they compare to Altec drivers I have used over the years. As for Coral drivers, I have heard good things about them but have no personal experiences.
Gary Dahl
Eldam ..... le # 35 it was for you also , I make a mistake
It was just like you to tell when your first response ...... with a light 8" the midrange and midbass deserves faster than a 12 "driver to bring out all nuances that there is in these frequencies....... that is all .....
" C'était seulement pour dire comme vous lors de votre première intervention ...... le médium et bas-médium mérite un driver plus rapide qu'un 12" pour faire ressortir toutes les nuances qu'il y a dans ces fréquences ...... c'est tout "
In the picture ..... Altec 420
It was just like you to tell when your first response ...... with a light 8" the midrange and midbass deserves faster than a 12 "driver to bring out all nuances that there is in these frequencies....... that is all .....
" C'était seulement pour dire comme vous lors de votre première intervention ...... le médium et bas-médium mérite un driver plus rapide qu'un 12" pour faire ressortir toutes les nuances qu'il y a dans ces fréquences ...... c'est tout "
In the picture ..... Altec 420
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If Audax France are today the owner of Coral Brand, I'm sure they will be happy to make it again if enough customers exist.
But here we have an idea of some todays factories : zero risks, zero will to advance! As writed elswhere they will just don't try under several hundred units already bought ! Marketing is not the speciality of many brands here
But here we have an idea of some todays factories : zero risks, zero will to advance! As writed elswhere they will just don't try under several hundred units already bought ! Marketing is not the speciality of many brands here
Yes, do it again today as the original would be very expensive because of the fields plates in Permaloy . Whatever ....... Voxatif (not listen to at this time) are very very expensive but I'm not sure they have a " instrumental timbre " like the Beta 8 (natural to desire). As you say .... there are not enough buyer for a business project. Mark Audio tries but they are still far away, they do not assimilate all the settings for optimized as Coral has finally found with time.
" Oui , le refaire aujourd'hui comme l'original serait très dispendieux à cause des plaques de champs en Permaloy . ....... quoi que Voxatif ( pas eu location de les entendrent encore ) sont très très dispendieux mais je ne suis pas sure qu'ils ont un timbre d'instrument comme celui du Beta 8 ( naturel à souhait ) . Comme vous le dites .... il n'y aurra pas assez d'acheteur pour rentabilisé le projet . Mark Audio essaye mais ils sont encore loin , ils n'ont pas assimiler tous les paramètres pour les optimisés comme Coral a finit par trouver avec le temps ."
Mais le PR170ZO ( Audax ) en le faisant travailler jusqu'à 200 hz avec un égalisateur digital , s'en approche beaucoup .
" Oui , le refaire aujourd'hui comme l'original serait très dispendieux à cause des plaques de champs en Permaloy . ....... quoi que Voxatif ( pas eu location de les entendrent encore ) sont très très dispendieux mais je ne suis pas sure qu'ils ont un timbre d'instrument comme celui du Beta 8 ( naturel à souhait ) . Comme vous le dites .... il n'y aurra pas assez d'acheteur pour rentabilisé le projet . Mark Audio essaye mais ils sont encore loin , ils n'ont pas assimiler tous les paramètres pour les optimisés comme Coral a finit par trouver avec le temps ."
Mais le PR170ZO ( Audax ) en le faisant travailler jusqu'à 200 hz avec un égalisateur digital , s'en approche beaucoup .
ALTEC 414
Hi Sebastien,
I've been informed by my brother that you are currently working on a "petite onken" project, or something similar, and plan to set the Altec 414 as woofers.
I'm the owner of a pair of DIY so-called "petite Onken", manufactured under the "Maison de l'Audiophile" plans and I use the Altec 414A for the job.
According to specific measurements I carried out by myself with a CLIO 3 equipment on a set of 5 different units, I found that their efficiency is rated at 95 dB, 1m, 1W.
According to my experience of this equipment, Clio generally emphysizes its measurement by approx 0.5 to 1dB. Difficult to be more precise.
So we could conclude that the efficiency of a 30years old Altec 414A, stored in good conditions, should stand in the range of 94-95dB.
In order to provide you with other interesting T&S parameters, as measured by CLIO, i'm enclosing the complete Clio record sheet.
Should you have other questions or dilemmas about this speaker, please feel free to dialog with me. I'll be happy to discuss about this amazing speaker.
Jerôme
Hi Sebastien,
I've been informed by my brother that you are currently working on a "petite onken" project, or something similar, and plan to set the Altec 414 as woofers.
I'm the owner of a pair of DIY so-called "petite Onken", manufactured under the "Maison de l'Audiophile" plans and I use the Altec 414A for the job.
According to specific measurements I carried out by myself with a CLIO 3 equipment on a set of 5 different units, I found that their efficiency is rated at 95 dB, 1m, 1W.
According to my experience of this equipment, Clio generally emphysizes its measurement by approx 0.5 to 1dB. Difficult to be more precise.
So we could conclude that the efficiency of a 30years old Altec 414A, stored in good conditions, should stand in the range of 94-95dB.
In order to provide you with other interesting T&S parameters, as measured by CLIO, i'm enclosing the complete Clio record sheet.
Should you have other questions or dilemmas about this speaker, please feel free to dialog with me. I'll be happy to discuss about this amazing speaker.
Jerôme
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