Panomaniac-I have few questions to you.....
what is your opinion about smaller versions of A7 (exact number is on top of my head..), meaning of versions with 811B horn ?
unfortunately-all I have from Altec is just a pair of mentioned 811B,along with (with them long time ago paired) pair of Goodmans T52 phenolic drivers......that was part of cinema box,made by Iskra (today and then -Iskra Ljubljana,Slovenia) ;you can see more at my www , on page about my cinema monoblocks-if you are interested
even today,13 or 14" Iskra low frequency driver (both iterations-Alnico and ceramic magnet version) can be reworked to amazing almost-full range driver with (wonder!) exceptionally low resonance and high sensitivity....
to cut a long story ,what is you experience with 811B ,comparing with multicells?
what is your opinion about smaller versions of A7 (exact number is on top of my head..), meaning of versions with 811B horn ?
unfortunately-all I have from Altec is just a pair of mentioned 811B,along with (with them long time ago paired) pair of Goodmans T52 phenolic drivers......that was part of cinema box,made by Iskra (today and then -Iskra Ljubljana,Slovenia) ;you can see more at my www , on page about my cinema monoblocks-if you are interested
even today,13 or 14" Iskra low frequency driver (both iterations-Alnico and ceramic magnet version) can be reworked to amazing almost-full range driver with (wonder!) exceptionally low resonance and high sensitivity....
to cut a long story ,what is you experience with 811B ,comparing with multicells?
Well Bear, at least you've heard some! Most folks have not. Sorry.
No, by no means do I want to imply that a stock A7 is worthy of the title "reference". Or maybe we should say "Good Reference".
That is why my pro sound buddies always scoffed at my love for the system.
And system is important. I'm talking about a completely reworked A7 cabinet skinned in 18 or 25mm extremely dense marine grade plywood with internal reinforcements and tar on the back of the horn flair. (Among other things). With an Altec 15 or 18 cell horn on top and a great driver, it's magic. The driver I know best is one that has been made since the 50s - A Westrex. But there may be modern drivers that could work as well. That driver and mullticell horn go a loooong way in contributing to the overall sound quality.
To answer choky.
The typical one-row horns like the 811 just don't sound as good. They sound nice, but lack the magic of the multicell horns. Well made wood horns of a similar profile are much better.
It certainly does! But many or most of them are not design flaws, just construction flaws.
Absolutely agree! There are some gems out there, but they are rare and expensive, as gems should be. A large room is certainly a good thing, but that is true of most systems. I've heard and used the modified A7s in many sized rooms, including outside and in the courtyard of a monastery. They sound good everywhere. But I never did try to squeeze them into my bedroom. Ouch!
Who's presuming now, bear?
But you may be right. I dunno. I've heard lots of extreme hi-fi systems and worked with plenty of pro sound rigs. What impressed me about the modified A7 system was that it sounds more like real music than anything else I've heard. Everything else I've heard sounds like a speaker to me. Maybe just ever so slightly, but it's there. The A7/mulitcell never did. No matter what amp I put in front it. Better amps sounded better, but bad amps never made the speakers sound like speakers, just music.
I will admit that I don't really know what "Modern Standards" are. I have heard systems that had more top or bottom octave than the A7/mulitcell. Certain systems had more detail, some had a bigger feeling of space. But none hit the musical reality nail on the head like the system I'm discussing. That’s my standard. But heck, even the guy who owns the A7s in question, Jean Hiraga, didn't agree with me. But he still has them and uses them as a reference almost 20 years later. And they still get rave reviews.
No, by no means do I want to imply that a stock A7 is worthy of the title "reference". Or maybe we should say "Good Reference".
That is why my pro sound buddies always scoffed at my love for the system.And system is important. I'm talking about a completely reworked A7 cabinet skinned in 18 or 25mm extremely dense marine grade plywood with internal reinforcements and tar on the back of the horn flair. (Among other things). With an Altec 15 or 18 cell horn on top and a great driver, it's magic. The driver I know best is one that has been made since the 50s - A Westrex. But there may be modern drivers that could work as well. That driver and mullticell horn go a loooong way in contributing to the overall sound quality.
To answer choky.
The typical one-row horns like the 811 just don't sound as good. They sound nice, but lack the magic of the multicell horns. Well made wood horns of a similar profile are much better.
It certainly does! But many or most of them are not design flaws, just construction flaws.
Absolutely agree! There are some gems out there, but they are rare and expensive, as gems should be. A large room is certainly a good thing, but that is true of most systems. I've heard and used the modified A7s in many sized rooms, including outside and in the courtyard of a monastery. They sound good everywhere. But I never did try to squeeze them into my bedroom. Ouch!
Who's presuming now, bear?
But you may be right. I dunno. I've heard lots of extreme hi-fi systems and worked with plenty of pro sound rigs. What impressed me about the modified A7 system was that it sounds more like real music than anything else I've heard. Everything else I've heard sounds like a speaker to me. Maybe just ever so slightly, but it's there. The A7/mulitcell never did. No matter what amp I put in front it. Better amps sounded better, but bad amps never made the speakers sound like speakers, just music.
I will admit that I don't really know what "Modern Standards" are. I have heard systems that had more top or bottom octave than the A7/mulitcell. Certain systems had more detail, some had a bigger feeling of space. But none hit the musical reality nail on the head like the system I'm discussing. That’s my standard. But heck, even the guy who owns the A7s in question, Jean Hiraga, didn't agree with me. But he still has them and uses them as a reference almost 20 years later. And they still get rave reviews.
bear said:
Greets!
Sorry, I saw nothing in your posts to indicate this. Regardless, the vents don't 'flow' any from the cab, or at least none loud enough to be audible due to their high air mass, instead they create pipe harmonics which comb filter out-of-phase with whatever driver system normally passes them. IOW, it can be Onken's driver, or if it's high passed fairly low, whatever the next one in the chain is. A typical Onken's are so strong that their impact is clearly evident beginning around 300 Hz in this measured plot (see attachment).
Oh well, you indicated having some prior exposure in a joelist thread, which typically includes its unique alignment jargon, so didn't feel the need to elaborate. Anyway, various 'n' numbers describe different ~standard vented box alignments, with '6.34' being a Butterworth. I don't know who developed them.
OK, thanks! Is this point adjustable, or.........?
'BR' = bass reflex. They do, but over a proportionately narrower BW. Right, and what do you get with a larger Sd? Greater acoustic gain due to greater acoustic efficiency.
GM
Attachments
Just want to share these for those who haven't seen it yet.. A la Onken Double (515s or EXC400s) to match their radial horn HF:
http://www.artec-france.com/etudes.php?lang=en&switch=Y
Nice that they share plans for diy.. The "compact" system using 2 Supra 285's look interesting too. They were designed for SS gear they manuf, so they may need further tuning (XO, etc.) for lower powered tube electronics. In their "reference" bassbin blueprint plan shows open cavities (horn), but in their construction they have sealed it off, which may be a better match with their SS electronics.
Maybe there are already some Onken guidlines in the Melaudia forums?
I have the early ('04) free version of a spreadhseet (in French) for reflex etc. published by Dominique Petoin. I dunno if it's ok to attach it here since his new version is for purchase already.
http://pageperso.aol.fr/petoindominique/doc_htm/br.htm
Can anyone tell me where to downlaod MJK's free BR sheet? I don't think it's in his website anymore. Thanks.
I was looking at planet10 Dave's site, and his FR125 'Fonken' looks cute. Do small standmount versions still have the benefit of what a large Jensen/Onken enclosure does?
http://www.artec-france.com/etudes.php?lang=en&switch=Y
An externally hosted image should be here but it was not working when we last tested it.
Nice that they share plans for diy.. The "compact" system using 2 Supra 285's look interesting too. They were designed for SS gear they manuf, so they may need further tuning (XO, etc.) for lower powered tube electronics. In their "reference" bassbin blueprint plan shows open cavities (horn), but in their construction they have sealed it off, which may be a better match with their SS electronics.
Maybe there are already some Onken guidlines in the Melaudia forums?
I have the early ('04) free version of a spreadhseet (in French) for reflex etc. published by Dominique Petoin. I dunno if it's ok to attach it here since his new version is for purchase already.
http://pageperso.aol.fr/petoindominique/doc_htm/br.htm
Can anyone tell me where to downlaod MJK's free BR sheet? I don't think it's in his website anymore. Thanks.
I was looking at planet10 Dave's site, and his FR125 'Fonken' looks cute. Do small standmount versions still have the benefit of what a large Jensen/Onken enclosure does?
I ask myself whether this is a candidate for beating the 288. The standard version already has an excellent reputation, and a coating that is twice as stiff as beryllium, that sounds interesting.
http://www.eighteensound.it/index.aspx?mainMenu=view_product&pid=182
http://www.eighteensound.it/index.aspx?mainMenu=view_product&pid=182
re: A7..
Here's an A7 inspired type enclosure from the 90's. From Rintelen's website (originally published in SP):
http://rintelen.ch/pdf/DIY/blue_thunder.pdf
Please note that the bass drivers used are no longer available and that the cabinet size would have to be recalculated for use with other drivers
When I look closely at the internal pic in the .pdf article, I think he didn't seal off the 'horn chambers'. It has minimal stuffing too, only thick lining of the walls actually. He still uses 'em afaik now with supertweeters, but in a different albeit more hardcore (heavy on quality signal iron and ccs stuff) diy tube tri-amp set up + active digital xo.
Has anyone here tried bi-amping using a line-level xo? Any success? This guy did just that for his TAD horn/reflex, using JMLC 18dB butterworth, and of course horn flare (Le Cleac'h). He used a passive transformer volume control or TVC -> XO -> 2 outputs for HF and LF. Shoe-box prototype below...
http://www.musique-concrete.com/Eguide_fichiers/boite_int.jpg
http://www.musique-concrete.com/Eguide_fichiers/LCR_schema.gif
http://www.musique-concrete.com/Eguide_fichiers/ELCR_feuille.xls
The 18sound line of Nd cd's look attractive, especially the lower cost polyethylene for higher freq cutoffs.
Here's an A7 inspired type enclosure from the 90's. From Rintelen's website (originally published in SP):
http://rintelen.ch/pdf/DIY/blue_thunder.pdf
Please note that the bass drivers used are no longer available and that the cabinet size would have to be recalculated for use with other drivers
When I look closely at the internal pic in the .pdf article, I think he didn't seal off the 'horn chambers'. It has minimal stuffing too, only thick lining of the walls actually. He still uses 'em afaik now with supertweeters, but in a different albeit more hardcore (heavy on quality signal iron and ccs stuff) diy tube tri-amp set up + active digital xo.
Has anyone here tried bi-amping using a line-level xo? Any success? This guy did just that for his TAD horn/reflex, using JMLC 18dB butterworth, and of course horn flare (Le Cleac'h). He used a passive transformer volume control or TVC -> XO -> 2 outputs for HF and LF. Shoe-box prototype below...
http://www.musique-concrete.com/Eguide_fichiers/boite_int.jpg
http://www.musique-concrete.com/Eguide_fichiers/LCR_schema.gif
http://www.musique-concrete.com/Eguide_fichiers/ELCR_feuille.xls
The 18sound line of Nd cd's look attractive, especially the lower cost polyethylene for higher freq cutoffs.
Interesting and thanks for the informative post. I had thought to do something similar with a three way passive line level x-over based on the line of cinemag inductors.
I have temporarily abandoned this approach due to the expense, I do have the requisite number of amplifiers, but the choice of inductors is quite limited and they are expensive particularly as I wanted to lightly load the output of my transformer coupled tube pre - it's not got a lot of gain even driving a high z load, driving a 600 ohm load would drop it about 4dB or so..
I am currently experimenting with my home brew spkr level 2nd order butterworth 3 way x-over. The onken cabs are not yet quite done, and the woofers won't be here until next week at the earliest.
I have been experimenting/tweaking the mid and tweeter horns the last few days while I wait to get to work on the bass section. (4333 and 2402) The sound is very clean, smooth, and.... unexciting. One thing that does stand out is the total apparent lack of driver distortion, this is about the cleanest sound I have heard - sanitary?? I don't think the small SE amplifier I am using to drive them is up to the task despite the very high efficiency. I think the words "layed back" describes the sound, and the highs really don't sound all that extended. Note the combined MF/HF and x-over are 8 ohms, and previous JBL 075/D130 based implementation is 16 ohms which in A/B sounds much livelier with this amplifier. (8 ohm tap)
I am going to swap in my 300B amplifier which is more dynamic, more extended and a lot faster sounding and see what happens.
I guess I need to purchase a measurement mic and pre shortly so I can get to the bottom of this.
I'm probably also over reacting, I determined that my average listening levels even with these require less than 10mWrms and usually less than 2mW. (No that's not a typo! Spl around 80dB typically)
I have temporarily abandoned this approach due to the expense, I do have the requisite number of amplifiers, but the choice of inductors is quite limited and they are expensive particularly as I wanted to lightly load the output of my transformer coupled tube pre - it's not got a lot of gain even driving a high z load, driving a 600 ohm load would drop it about 4dB or so..
I am currently experimenting with my home brew spkr level 2nd order butterworth 3 way x-over. The onken cabs are not yet quite done, and the woofers won't be here until next week at the earliest.
I have been experimenting/tweaking the mid and tweeter horns the last few days while I wait to get to work on the bass section. (4333 and 2402) The sound is very clean, smooth, and.... unexciting. One thing that does stand out is the total apparent lack of driver distortion, this is about the cleanest sound I have heard - sanitary?? I don't think the small SE amplifier I am using to drive them is up to the task despite the very high efficiency. I think the words "layed back" describes the sound, and the highs really don't sound all that extended. Note the combined MF/HF and x-over are 8 ohms, and previous JBL 075/D130 based implementation is 16 ohms which in A/B sounds much livelier with this amplifier. (8 ohm tap)
I am going to swap in my 300B amplifier which is more dynamic, more extended and a lot faster sounding and see what happens.
I guess I need to purchase a measurement mic and pre shortly so I can get to the bottom of this.
I'm probably also over reacting, I determined that my average listening levels even with these require less than 10mWrms and usually less than 2mW. (No that's not a typo! Spl around 80dB typically)
Hi el ' ol,
If it's not a bother, is it possible for you to email me MJK's old BR sheet? I'd really appreciate it if you have the time. Thank you.
kevin,
You could always use stock coils of CPV (closest preferred value). But if you want accuracy maybe custom aircoils are the most cost effective. I'm not sure how much Dave Slagle charges for custom wound coils. You could contact him or join the forums at www.intactaudio.com
The passive speaker level xo is more dependent on amp types and power. So maybe you'd be better off with your custom 300B amps for dynamics even at low spl's.
When I get the chance to build up a more $ system such as yours I'd like to try chipamps or class d types for the LF. However, unless I use padding R's for the line-level xo (if possible), I'd have to consider output power and driver/s' effiiciency level matching. HF would be valve powered.
If it's not a bother, is it possible for you to email me MJK's old BR sheet? I'd really appreciate it if you have the time. Thank you.
kevin,
You could always use stock coils of CPV (closest preferred value). But if you want accuracy maybe custom aircoils are the most cost effective. I'm not sure how much Dave Slagle charges for custom wound coils. You could contact him or join the forums at www.intactaudio.com
The passive speaker level xo is more dependent on amp types and power. So maybe you'd be better off with your custom 300B amps for dynamics even at low spl's.
When I get the chance to build up a more $ system such as yours I'd like to try chipamps or class d types for the LF. However, unless I use padding R's for the line-level xo (if possible), I'd have to consider output power and driver/s' effiiciency level matching. HF would be valve powered.
Re Onken Enclosures
A big thanks to everybody who has contributed to this thread to date. Some worthwhile information coming out which is helping to crystalise in my mind how I want to go in the future. Obviously a fairly expensive undertaking as far as suitable drivers go but in time I should get there. they say good things are worth waiting for!!!
jamikl
A big thanks to everybody who has contributed to this thread to date. Some worthwhile information coming out which is helping to crystalise in my mind how I want to go in the future. Obviously a fairly expensive undertaking as far as suitable drivers go but in time I should get there. they say good things are worth waiting for!!!
jamikl
Hi GM,
I hope I'm not infiringing on MJK's license agreement as his Worksheets are of course proprietary. I wouldnt want to encourage any unlawful distribution of any sort. If the specific BR worksheet is the "old" free downloadable version maybe it's okay to share it for diy (I just have the mathcad trial version to educate myself with 1st), but if not, please let me know as I would ask el`ol to cancel my request. Thank you.
fred
I hope I'm not infiringing on MJK's license agreement as his Worksheets are of course proprietary. I wouldnt want to encourage any unlawful distribution of any sort. If the specific BR worksheet is the "old" free downloadable version maybe it's okay to share it for diy (I just have the mathcad trial version to educate myself with 1st), but if not, please let me know as I would ask el`ol to cancel my request. Thank you.
fred
Greets!
I don't have his shareware? (fee paid) WSs, only his old MC2K freeware versions (which can be saved as MC8 versions) since I only use them to help others with their speaker related Qs/projects. I'm not even sure if I have the most up-to-date versions of them for that matter.
Anyway, these are in the public domain with his obvious consent since they were downloadable from his site, so there's no infringement unless used for any profit other than personal satisfaction.
GM
I don't have his shareware? (fee paid) WSs, only his old MC2K freeware versions (which can be saved as MC8 versions) since I only use them to help others with their speaker related Qs/projects. I'm not even sure if I have the most up-to-date versions of them for that matter.
Anyway, these are in the public domain with his obvious consent since they were downloadable from his site, so there's no infringement unless used for any profit other than personal satisfaction.
GM
Hi GM,
Thanks for clarifying, as I just wanted to make sure. Mathcad would be a steep learning curve (at least for me). It's more of an educational thing for me really (with some tutoring from an engineer bud who designs our bespoke phono preamp). Anyways, I have no intention of using the WS for commercial purposes or profit.
Hi el`ol,
Got your email. Thanksabunch. Would gladly send MJK an MO (no paypal available here) if I get the newest WS versions.
Thanks for clarifying, as I just wanted to make sure. Mathcad would be a steep learning curve (at least for me). It's more of an educational thing for me really (with some tutoring from an engineer bud who designs our bespoke phono preamp). Anyways, I have no intention of using the WS for commercial purposes or profit.
Hi el`ol,
Got your email. Thanksabunch. Would gladly send MJK an MO (no paypal available here) if I get the newest WS versions.
I'm not looking to get into a big discussion about the merits of the A7 or the Onken... I'll make just a few comments though:
An unlined cabinet with a large vent area, as in the Onken or even the A7 will certainly permit the emission of sound other than the intended pass band of the "vent/port." How much will vary according to the geometry and the reflectivity of the enclosure.
I assure you that it will be audible and measureable. The question then is if it is objectionable or detracts from performance.
A comb filter is non flat anyhow, so even if this was what was going on, it wouldn't be terribly effective.
We may have a language disconnect here, but I am not sure what you are speaking about with the part about their "impact" and "300Hz." The Onken would be lowpassed, the next speaker up in frequency would be high passed (or band passed as the case may be).
GM said:
An unlined cabinet with a large vent area, as in the Onken or even the A7 will certainly permit the emission of sound other than the intended pass band of the "vent/port." How much will vary according to the geometry and the reflectivity of the enclosure.
I assure you that it will be audible and measureable. The question then is if it is objectionable or detracts from performance.
A comb filter is non flat anyhow, so even if this was what was going on, it wouldn't be terribly effective.
We may have a language disconnect here, but I am not sure what you are speaking about with the part about their "impact" and "300Hz." The Onken would be lowpassed, the next speaker up in frequency would be high passed (or band passed as the case may be).
Oh well, you indicated having some prior exposure in a joelist thread, which typically includes its unique alignment jargon, so didn't feel the need to elaborate. Anyway, various 'n' numbers describe different ~standard vented box alignments, with '6.34' being a Butterworth. I don't know who developed them.
[\quote]
I see - I think these are the "old" filter alignment numbers.
These days one does not see them used much, since T/S design has more or less supplanted them in practical design methodology... afaik.
Ummm, not really except to the extent that it is a function of DF, or lack thereof. So to the extent that one could design an amp with adjustable feedback or build the amp to "match" the enclosure in this respect it is possible. I have not had personal experience with this technique being very effective, but it has been reported as being so.
Yeah BR = bass reflex - should have realized that!
I'm not sure about this. It seems to me that since your driving force is a constant, that as you increase the effective Sd of the port, there is no overall change in the "acoustic gain." There is a change in the effective radiation impedance as you go from a smaller area to a larger area. But that is offset by a reduction of force per surface area. Especially if the "Q" drops along with the increase in area...
GM
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.