You're welcome!
Good plan with these drivers. For future reference though................
I assume this is just the nominal tap rating, so isn't what we're referring to: Amplifier Output Impedance
This doesn't rule out their output impedance being this high or even higher, I've seen as high as 20 ohms back when horn drivers were typically 16 ohms, so there's the matter of driver selection when driven by a high output impedance which make the 2510 a poor choice if not in a TL or similar loading since it already has a Qts on the high side for vented box loading: Highly Reactive Loads and SET Amplifiers
Regardless, to fully realize the inherent potential of all SET tube and OTL amps, a loudspeaker of 14 ohms or greater is mandatory to maximize power conversion efficiency. Anything less involves a huge compromise, so most drivers will need to be wired in series.
GM
You thought right
, I uploaded CMD's to e-snips back in '08 after folks complained about all the original links being dead.GM
Lars,
Active might be a good idea, but my intention is to run passive for a three way system. I thought I better go with the tradition route with 414 since infos are easily available.
Albert
Hey,
I´ve got a small stash of 414-8A(must be -A or -B) and earlier ran "Petite Onken". I am now working on a midbass-horn for them. With PT best results where achieved with active. Whatever they sound great.
Take a look in the spreadsheet what happens when adding external resistance. Your tube amps will not do. But adding 0,2ohm and running SS will not harm.
I´ve got a small stash of 414-8A(must be -A or -B) and earlier ran "Petite Onken". I am now working on a midbass-horn for them. With PT best results where achieved with active. Whatever they sound great.
Take a look in the spreadsheet what happens when adding external resistance. Your tube amps will not do. But adding 0,2ohm and running SS will not harm.
Good to know, thanks! It doesn't seem to work quite the same for me though WRT to in. 350.1 cm^2 in m^2 converted it to milliliters, but when to was used it did the conversion correctly. For now though, I think I'll stick to using Convert.
GM
Hey guys,
I´ve taken the liberty to adjust the spreadsheet to take Sd in cm^2. Also removed one unnecessary decimal.
Actually the original Onken calculations from the Petite Onken article in L´Audiophile " only needs Vas, Qts and Fs or Mms, Qts, Sd and Fs. One might then add Re to make it possible to input Rg.
Maybe I should reduce the spreadsheet to make it less confusing?
http://www.revintage.se/ONKENcm3.xls
I´ve taken the liberty to adjust the spreadsheet to take Sd in cm^2. Also removed one unnecessary decimal.
Actually the original Onken calculations from the Petite Onken article in L´Audiophile " only needs Vas, Qts and Fs or Mms, Qts, Sd and Fs. One might then add Re to make it possible to input Rg.
Maybe I should reduce the spreadsheet to make it less confusing?
http://www.revintage.se/ONKENcm3.xls
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This is a somewhat easier to read spreadsheet. Qms and Qes are needed for adding Rg. The starting figures are for "Petite Onken" with Altec 414-8A/B.
http://www.revintage.se/ONKENcm3414.xls
http://www.revintage.se/ONKENcm3414.xls
I actually did this right after it was published and suggested it in a pm, but got no response IIRC. At the time, JMMLC was helping me update mine when time permitted after Guy Pelletier [another French Canadian] I had met on one of the mailing lists pointed out that my formulas didn't match the original's; but the day I went on-line to announce I had a proper Onken calculator available, I found CMB's had beat me to it, so didn't bother since I didn't want to 'steal his thunder'.
Apparently he considered my suggestion rude/whatever because the next time I posted on one his threads he got really rude/cross with me for no apparent reason, basically telling me he wasn't interested in anything I had to say IIRC.
I started to upload it or mine when the old links went dead and again the other day, but having never seen the original document
Not that I care though as I've periodically noted along with the 'why' and all things considered, wished I'd gone ahead and posted mine anyway to give folks another option.
Regardless, if I wanted a fine performing cab with the Onken 'look' for dual 2510s, I'd make the vents full size and as long as required and damp the cabs to 'taste' same as a TL, though wouldn't drive them with a high output impedance since it will make the them relatively to outright huge depending on how high it is.
GM
It is nothing special about the Onken concept expect for the n=6,34 and the ports being equal in area to Sd. About the ports it should be mentioned that I have an article from the L´Audiophile with two 515 and very small ports and L the same as the baffle thickness!
It should also be mentioned that Onken is nothing but a 4th order Butterworth bassreflex.
This one, (but not in Excel at first) that I made years ago(when the article was published) is by the book as I used the L´Audiophile(I have very issue of it) article.
http://www.revintage.se/Onken.xls
That is the same as mine and also by the book. See the left version in my spreadsheet.
As you see there is no provision for Rg. So CMD´s isn´t by the book but taken a step further. As I remember it there was another article just after this where the provision was added. Will check how it was done.
The 2510´s gives us a very long port which isn´t the best but it will surely work.
It should also be mentioned that Onken is nothing but a 4th order Butterworth bassreflex.
This one, (but not in Excel at first) that I made years ago(when the article was published) is by the book as I used the L´Audiophile(I have very issue of it) article.
http://www.revintage.se/Onken.xls
That is the same as mine and also by the book. See the left version in my spreadsheet.
As you see there is no provision for Rg. So CMD´s isn´t by the book but taken a step further. As I remember it there was another article just after this where the provision was added. Will check how it was done.
The 2510´s gives us a very long port which isn´t the best but it will surely work.
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This is what JMMLC said, though WRT Sd'/Sd = 1.0, a couple of others have claimed that the Onken ideology was to use 0.9.
Yes, according to JMMLC, Onken [the company] products for the most part didn't conform to any of this, so how did this arcane design routine come about? To me, it's based primarily on Thuras's patent reflex experimental cab that Jensen resurrected as the Ultraflex.
IOW, build what you want as long as it has a multiple ducted port vent system that's large enough in total area to be around Sd and long enough to audibly 'color' [distort] the lower mids.
The caveat is that with today's [ultra] low Vas drivers, getting a large enough vent area [Av] can mean organ pipe long vents, so at this point it needs to either be somewhat aperiodic or go with a MLTL to get some 1/4 WL loading on a single large vent to further shorten it, which is what I've been doing since '68 when I got educated on the underlying theory of Olson's original [late '40s?] LC-1A high aspect ratio 'reflex' cab. He missed a good patent/marketing opportunity with that one since 'conventional wisdom' dictated that the vent be as close as practical to the driver.
BTW, how was the 'n' and 'k' number derived? Of what value is the 'k' frequency calculation? Since it doesn't use 'k', shouldn't it be a calculated value from Fs, 'n'? If JMMLC explained all this to me, it's become lost over the last ~11 years and some of the other partial explanations I've seen posted made no sense to me, so didn't save any of them.
GM
Yes, according to JMMLC, Onken [the company] products for the most part didn't conform to any of this, so how did this arcane design routine come about? To me, it's based primarily on Thuras's patent reflex experimental cab that Jensen resurrected as the Ultraflex.
IOW, build what you want as long as it has a multiple ducted port vent system that's large enough in total area to be around Sd and long enough to audibly 'color' [distort] the lower mids.
The caveat is that with today's [ultra] low Vas drivers, getting a large enough vent area [Av] can mean organ pipe long vents, so at this point it needs to either be somewhat aperiodic or go with a MLTL to get some 1/4 WL loading on a single large vent to further shorten it, which is what I've been doing since '68 when I got educated on the underlying theory of Olson's original [late '40s?] LC-1A high aspect ratio 'reflex' cab. He missed a good patent/marketing opportunity with that one since 'conventional wisdom' dictated that the vent be as close as practical to the driver.
BTW, how was the 'n' and 'k' number derived? Of what value is the 'k' frequency calculation? Since it doesn't use 'k', shouldn't it be a calculated value from Fs, 'n'? If JMMLC explained all this to me, it's become lost over the last ~11 years and some of the other partial explanations I've seen posted made no sense to me, so didn't save any of them.
GM
Attachments
I have Hiragas book "Loudspeakers" somewhere. As I remember "n" was well described there.
This is a short article about Onken W. As you see, no long ports.
http://www.audioheritage.org/vbulletin/showthread.php?27401-Onken-Dual-15-quot-quot-Onken-W-quot
This is a short article about Onken W. As you see, no long ports.
http://www.audioheritage.org/vbulletin/showthread.php?27401-Onken-Dual-15-quot-quot-Onken-W-quot
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Just for fun I added a feature to choose the number of drivers you want to run in parallell:
http://www.revintage.se/ONKENcm3414.xls
http://www.revintage.se/ONKENcm3414.xls
I think I am with revintage on this one. The crucial part seems to be the speaker in box alignment of 6.34. It may have been accidental that the vent size is so large unless he was trying, as GM suggested, to do something like the Thuras patent.
My feeling is that as long as the in box alignment is 6.34 then make the vents as large as you can whilst keeping to a reasonable length and putting the vents near the speaker, maybe each side. I think the idea of stuffing the ports slightly is probably good as well. This is just intuition - no experience to back up what ideas I've come to unlike GM and revintage.
jamikl
My feeling is that as long as the in box alignment is 6.34 then make the vents as large as you can whilst keeping to a reasonable length and putting the vents near the speaker, maybe each side. I think the idea of stuffing the ports slightly is probably good as well. This is just intuition - no experience to back up what ideas I've come to unlike GM and revintage.
jamikl
When the two drivers share internal volume, is the measure mentioned double what each individual drivers need or is there more to the eqasiom? I use bass box pro to model, there is no multiple drivers option.
Might seem like a stupid question, but doubling a recipe often it's not just all ingredients go 1-2.
Might seem like a stupid question, but doubling a recipe often it's not just all ingredients go 1-2.
Odd. I haven't used BassBox 6 Pro in a while but previously I calculated box details for pairs of driver and as many as 16 drivers per box.
When you enter your new design the first question under the configuration tab is number of drivers query. You answer that question and work through the mechanical and electrical configurations. You enter the box parameters for a single driver as you move along and BBP will calculate the overall box values and such.
Works great! Of course you have to increase the overall box size as you work along to maintain similar responses if you are trying to have similar box tuning to a single driver.
When you enter your new design the first question under the configuration tab is number of drivers query. You answer that question and work through the mechanical and electrical configurations. You enter the box parameters for a single driver as you move along and BBP will calculate the overall box values and such.
Works great! Of course you have to increase the overall box size as you work along to maintain similar responses if you are trying to have similar box tuning to a single driver.
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