Greets!
The BMS is a poor choice also, though for a different reason. Today's prosound drivers have very stiff suspensions to keep Vas as low as practical to keep box size user/shipping/storing 'friendly', which yields a similar underdamped response as the high Qt drivers, though if you stuff the vents its response is somewhat better overall Vs the high Qt drivers. Still, it defeats the point of building an Onken, so why bother?
To keep the vent length <35 cm, a n = 18.4! was required, another consequence of the driver's relatively small Vas.
GM
The BMS is a poor choice also, though for a different reason. Today's prosound drivers have very stiff suspensions to keep Vas as low as practical to keep box size user/shipping/storing 'friendly', which yields a similar underdamped response as the high Qt drivers, though if you stuff the vents its response is somewhat better overall Vs the high Qt drivers. Still, it defeats the point of building an Onken, so why bother?
To keep the vent length <35 cm, a n = 18.4! was required, another consequence of the driver's relatively small Vas.
GM
Attachments
I start to believe that an Onken is a good thing for a midwoofer, but not ideal for a sub. In the last Hobby Hifi they had a Linkwitz style dipole sub with 18" drivers, quite simple correction and very good frequency response. You have to move some air to make the acoustic short-circuit become irrelevant, and obviously this also works with large surface, not just with shwabbly 30mm excursion drivers.
Yeah I don't think the Onken would be my first choice for performance below 30Hz unless I had a lot of room..
According to my simulations the Eminence Delta Pro 15A will work well provided that you keep source impedance under an ohm or so. There are several other eminence drivers like the kappa pro which I think might also work ok. You may find several less expensive Eminence drivers that will work with the right rg in series with them.
I am currently building onken cabinets which will be stuffed with Iconic Speakers 165-8G. These are midbass drivers designed for horn loading and have an FS near 40Hz. These are basically the same as the last "real" pre Spark-O-Matic version of the Altec Lansing 515.
I designed my cabs to work with a number of drivers, with some compromises for some choices. Cabinet/port dimensions are fixed, only n and rg can be varied. Within those limits several drivers work well. The Iconic is the best match to the box, and despite its really high price tag is what I am getting.
I suspect it might be easier to design using an inexpensive 15" which is probably less expensive than even two inexpensive 12". Surface area of 2 x 12" is pretty close to that of a single 15" as well.
As GM states I will be using a fair amount of series resistance to get the low frequency performance I am looking for.
My cabs overall volume is about 11 cu ft. N=5.7 and -3dB right around 38Hz. Efficiency about 97dBspl estimated.
I just got a pair of JBL 4333 midrange horns with diffusers and am for the moment going to use a pair of either Fane st.5020 slot loaded horn tweeters or the st.5022 bullet. Later will go with JBL 2402 slots in all likelyhood.
Wrestling with the active/passive x-over routine, both are viable as I have plenty of amplifiers. A good active x-over that doesn't cost as much as the speaker system is a problem. (I'm using an all tube system.) A good passive x-over is non trivial design wise.
As I get all of this stuff together I will post my experiences.
According to my simulations the Eminence Delta Pro 15A will work well provided that you keep source impedance under an ohm or so. There are several other eminence drivers like the kappa pro which I think might also work ok. You may find several less expensive Eminence drivers that will work with the right rg in series with them.
I am currently building onken cabinets which will be stuffed with Iconic Speakers 165-8G. These are midbass drivers designed for horn loading and have an FS near 40Hz. These are basically the same as the last "real" pre Spark-O-Matic version of the Altec Lansing 515.
I designed my cabs to work with a number of drivers, with some compromises for some choices. Cabinet/port dimensions are fixed, only n and rg can be varied. Within those limits several drivers work well. The Iconic is the best match to the box, and despite its really high price tag is what I am getting.
I suspect it might be easier to design using an inexpensive 15" which is probably less expensive than even two inexpensive 12". Surface area of 2 x 12" is pretty close to that of a single 15" as well.
As GM states I will be using a fair amount of series resistance to get the low frequency performance I am looking for.
My cabs overall volume is about 11 cu ft. N=5.7 and -3dB right around 38Hz. Efficiency about 97dBspl estimated.
I just got a pair of JBL 4333 midrange horns with diffusers and am for the moment going to use a pair of either Fane st.5020 slot loaded horn tweeters or the st.5022 bullet. Later will go with JBL 2402 slots in all likelyhood.
Wrestling with the active/passive x-over routine, both are viable as I have plenty of amplifiers. A good active x-over that doesn't cost as much as the speaker system is a problem. (I'm using an all tube system.) A good passive x-over is non trivial design wise.
As I get all of this stuff together I will post my experiences.
Re: Re: Old thread
Most likely. I think Nantex is gone, now. But it made a wonderful speaker cabinet. Any good, solid, no void marine plywood ought to do the same, yeah?
Below you will see a image taken from Jean Hiraga's 1977 article about the Onken. It shows the 25mm custom made "Shinban" plywood used by Onken. The plies were curved away from center before assembly, then hot glued in a ultrasonic 10 ton press.
The original Onken is said to be superior to even perfectly made copies, mostly because of the wood.
Hiraga also goes on to say that using inferior quality wood of double thickness really does not help anything. He suggests high quality marine plywood.
As for the bass reflex thing, Hiraga notes in the article that the Onken box is not a bass reflex, but rather an acoustic low pass filter.
Here is the equivalent circuit.
The caption says:
Equivalent Circuit of the Onken cabinet. This system was proposed by the Jensen firm before 1950. Very close to the "Acoustic Line" we see however, despite its exterior aspect, this cabinet is not of the "Bass Reflex" type. This equivalent circuit is, in fact, a damped low pass filter and not a resonant circuit.
Alas Hiraga does not give any formulas for calculating the Onken/Jensen enclosure. He simply says to use an Altec 416-8A as after many tests it is the only driver to give results close to the original Onken (in the 360 liter box).
It's interesting to note that the Onken version was introduced in 1973 and by 1977 more than 4500 Japanese DIYers had built one!
Time for me to cough up 50 Euro for the back issues of the Audiophile Revue on CD. Should be more info there.
GM said:
Most likely. I think Nantex is gone, now. But it made a wonderful speaker cabinet. Any good, solid, no void marine plywood ought to do the same, yeah?
Below you will see a image taken from Jean Hiraga's 1977 article about the Onken. It shows the 25mm custom made "Shinban" plywood used by Onken. The plies were curved away from center before assembly, then hot glued in a ultrasonic 10 ton press.
The original Onken is said to be superior to even perfectly made copies, mostly because of the wood.
An externally hosted image should be here but it was not working when we last tested it.
Hiraga also goes on to say that using inferior quality wood of double thickness really does not help anything. He suggests high quality marine plywood.
As for the bass reflex thing, Hiraga notes in the article that the Onken box is not a bass reflex, but rather an acoustic low pass filter.
Here is the equivalent circuit.
An externally hosted image should be here but it was not working when we last tested it.
The caption says:
Equivalent Circuit of the Onken cabinet. This system was proposed by the Jensen firm before 1950. Very close to the "Acoustic Line" we see however, despite its exterior aspect, this cabinet is not of the "Bass Reflex" type. This equivalent circuit is, in fact, a damped low pass filter and not a resonant circuit.
Alas Hiraga does not give any formulas for calculating the Onken/Jensen enclosure. He simply says to use an Altec 416-8A as after many tests it is the only driver to give results close to the original Onken (in the 360 liter box).
It's interesting to note that the Onken version was introduced in 1973 and by 1977 more than 4500 Japanese DIYers had built one!
Time for me to cough up 50 Euro for the back issues of the Audiophile Revue on CD. Should be more info there.
Re: Re: Re: Old thread
Greets!
Yes, any of the no-void plywoods at least 3/4" (19 mm) thick works well if braced. Here in the USA though, marine grade is not marketed as no-void anymore so I no longer recommend it, only 11-13 ply Baltic Birch and Apple ply. Bamboo ply should work well too if no-void.
He's absolutely right in that doubling inferior wood is just doubling your potential problems WRT cab 'creak' or 'squeak'.
A BR is a low pass filter and unless you design it as such, it's aspect ratio isn't high enough to be a ML-TL, though his plot's incorrect in that it's incomplete since it doesn't show the vent's pipe harmonics. To become a proper acoustic line, the vents must be considerably longer, like what is required for most current drivers, though its vents are obviously better damped than a typical BR's due to their sheer air mass.
GM
Greets!
Yes, any of the no-void plywoods at least 3/4" (19 mm) thick works well if braced. Here in the USA though, marine grade is not marketed as no-void anymore so I no longer recommend it, only 11-13 ply Baltic Birch and Apple ply. Bamboo ply should work well too if no-void.
He's absolutely right in that doubling inferior wood is just doubling your potential problems WRT cab 'creak' or 'squeak'.
A BR is a low pass filter and unless you design it as such, it's aspect ratio isn't high enough to be a ML-TL, though his plot's incorrect in that it's incomplete since it doesn't show the vent's pipe harmonics. To become a proper acoustic line, the vents must be considerably longer, like what is required for most current drivers, though its vents are obviously better damped than a typical BR's due to their sheer air mass.
GM
I've never heard the La Scala, but it sure gets written about a lot. Maybe some day.
I loved the Onkens I heard much better than any other direct radiator of any style.
However, my favorite bass cabinet of all time is the good old VOTT A7. Reskinned with (above mentioned) Nantex, braced and reported, it was fantastic. Just a big BR with short horn. But did not sound like a box at all.
Just sounded like real music, played by real instruments. (a big Altec 1808 multi-cell mid horn sure helped).
So I guess the Onken alignment is going to be difficult with modern drivers?
I loved the Onkens I heard much better than any other direct radiator of any style.
However, my favorite bass cabinet of all time is the good old VOTT A7. Reskinned with (above mentioned) Nantex, braced and reported, it was fantastic. Just a big BR with short horn. But did not sound like a box at all.
Just sounded like real music, played by real instruments. (a big Altec 1808 multi-cell mid horn sure helped).
So I guess the Onken alignment is going to be difficult with modern drivers?
panomaniac said:
Greets!
I've been waiting for this Q.
Someone with much better math skills than me can probably derive a fairly accurate formula or set of formulas to make it easier, but about the best I could come up with was to use the old EBP (efficiency BW product) rule-of-thumb, Fs/Qts, with values >70. If there's one for Vas, I don't have a clue, so use a licensed copy of BoxPlot to quickly check the driver's T/S desired Fb alignment with the vent's area set to ~Sd to make sure it's not too long, though from experience some are just obvious to me, like the BMS with its 288 L for an 18" Vs the 360L Onken's ~750 L/15" driver. GM
panomaniac said:
Greets!
My second 'serious' pair of DIY speakers were well braced/damped A7 clones and I really enjoyed them until I was able to step up to 515B loaded 210s.
BTW, the cab is technically a crude BLH with two narrow BW damping chambers, ergo when used with baffle boards it's a mass loaded BLH and why it doesn't sound like a typical big BR. What's an 1808? There were no 800 Hz 18 cell horns AFAIK, only 300, 400 Hz versions: 1803, 1804. Do you mean the H808, the 8 cell/800 Hz horn used on the original Iconic and 800 VOT?
For the most part since 'shrinking cab syndrome' runs rampant through the speaker manufacturing community and will continue to do so.
GM
GM said:
Sorry, typo on my part. I meant the 1803 (I keep typing it wrong)... The big 18 cell horn, you know the one. Maybe the best they ever made. Quite amazing. Used a pair of 50's vintage Westrex drivers, also very nice.
I would be fun to make clones of the 1803 in some cheap labor - low tech country. But who would buy them? Too big. Just buy little satellites and a sub, that's all you really need.
The same Westrex drivers also worked very well with the giant W.E. 15A horn. Onken W cabinet on the bottom. Huge sounding system. Never heard anything else get close. We were going to use 210s on the bottom, but someone stole one!
You must have a very large listening room.
Greets!
Oh yeah! Loaded with Westrex I bet they were something else! My experience has been limited to the Altec drivers they were voiced with.
Yeah, between the size and too large a polar response for a typical stereo system, that would be a tough sell. I had 805s with the 210s, but wound up switching to 511s since they were better performers overall. I hated giving up the 805's stronger mids though, but back in the late '60s there was no digital delay and my hearing was good enough that using a super tweeter sounded horrible, so by the time I passively EQ'd the 805s ~flat, there wasn't enough dynamic headroom left for when we'd roll them out onto the patio for weekend parties.
When I was a teen there was a theater down south of me with the original mono WE field coil system, and in the 'sweet spot' the voice was to die for, but this is where I learned first hand about the need to time align hybrid systems and the off axis problems of long horns. It's one thing to read about it in a book and quite another to move around in a theater and hear the echos and 'chopping up'/roll off of the HF.
When I had full size 210s (three, no less!), we did have a fairly large room, ~46 ft x 26 ft with 16 ft cathedral ceiling, which included an open area kitchen and 'formal' dining area. The house wasn't all that large, a typical suburbia tri-level, but we had it specially built with the main floor being completely open in what was called a 'great room' layout, a (local?) fad of the day. The 210s normally laid flat on their sides with the center one being a derived 3rd channel to mimic the original Bell Labs 'stereo' system.
Later, the system was reduced to two with the horns cut out and modded for corner placement perched on top of subs so they would fit in a much smaller house/room that's nominally ~16 ft x 21.5 ft with standard 8 ft ceiling, but it too has been opened up to the rear somewhat so that there's a small hallway and bedroom in line that yields an effective acoustic pathlength of ~46 ft with a large resonant trap, so no boomy bass line.
Some years ago I had to have a 'fire sale' though to 'feed' an overly greedy healthcare system, so now all I have is some mostly stock 511s perched on top of the old dual 515B EBS subs.
GM
Oh yeah! Loaded with Westrex I bet they were something else! My experience has been limited to the Altec drivers they were voiced with.
Yeah, between the size and too large a polar response for a typical stereo system, that would be a tough sell. I had 805s with the 210s, but wound up switching to 511s since they were better performers overall. I hated giving up the 805's stronger mids though, but back in the late '60s there was no digital delay and my hearing was good enough that using a super tweeter sounded horrible, so by the time I passively EQ'd the 805s ~flat, there wasn't enough dynamic headroom left for when we'd roll them out onto the patio for weekend parties.
When I was a teen there was a theater down south of me with the original mono WE field coil system, and in the 'sweet spot' the voice was to die for, but this is where I learned first hand about the need to time align hybrid systems and the off axis problems of long horns. It's one thing to read about it in a book and quite another to move around in a theater and hear the echos and 'chopping up'/roll off of the HF.
When I had full size 210s (three, no less!), we did have a fairly large room, ~46 ft x 26 ft with 16 ft cathedral ceiling, which included an open area kitchen and 'formal' dining area. The house wasn't all that large, a typical suburbia tri-level, but we had it specially built with the main floor being completely open in what was called a 'great room' layout, a (local?) fad of the day. The 210s normally laid flat on their sides with the center one being a derived 3rd channel to mimic the original Bell Labs 'stereo' system.
Later, the system was reduced to two with the horns cut out and modded for corner placement perched on top of subs so they would fit in a much smaller house/room that's nominally ~16 ft x 21.5 ft with standard 8 ft ceiling, but it too has been opened up to the rear somewhat so that there's a small hallway and bedroom in line that yields an effective acoustic pathlength of ~46 ft with a large resonant trap, so no boomy bass line.
Some years ago I had to have a 'fire sale' though to 'feed' an overly greedy healthcare system, so now all I have is some mostly stock 511s perched on top of the old dual 515B EBS subs.
GM
Hi,
there are some L'Audiophile - Onken articles at melaudia site:
http://www.melaudia.net/litterature.php
Vuki
there are some L'Audiophile - Onken articles at melaudia site:
http://www.melaudia.net/litterature.php
Vuki
Vuki- Thanks so much! Very cool.
While most guys here will be interested in the Onken articles, I was very happy to find the articles about the big system demos at "Espace Kiron". I put together the 1st one, as I was technical director at Kiron in the mid 80's.
What a system! Certainly the high point in my hi-fi experience. The sense of space was unbelievable, just jaw dropping. That demo went on to become legend.
They've done a few more sense then. Good to see a photo of my trusty old A7. Nice box.
I'll have a look at the Onken stuff as soon as I'm through delighting in all my audio nostalgia.
GM, that quite a line up you have (had) there, You certainly know the good stuff! (BTW, I know where a pair of Vitaphone 11 Foot horns are hiding, but don't tell anyone).
While most guys here will be interested in the Onken articles, I was very happy to find the articles about the big system demos at "Espace Kiron". I put together the 1st one, as I was technical director at Kiron in the mid 80's.
What a system! Certainly the high point in my hi-fi experience. The sense of space was unbelievable, just jaw dropping. That demo went on to become legend.
They've done a few more sense then. Good to see a photo of my trusty old A7. Nice box.
I'll have a look at the Onken stuff as soon as I'm through delighting in all my audio nostalgia.
GM, that quite a line up you have (had) there, You certainly know the good stuff! (BTW, I know where a pair of Vitaphone 11 Foot horns are hiding, but don't tell anyone).
So after looking thru all those Onken articles, still no formulas or guidelines!
Just plans and construction tips. L'Audiophile must have published formulas at some time - but they must be "Hiding".
The Onken W is an odd beast. I know it well - sounds great - but why is it called Onken? And why W? AFAIK, it is just a big box with 2 small ports, 1 in each upper corner. None of the multiple vents along the sides that we generally think of as an ONKEN/ULTRAFLEX box. What's up with that? Or is there something I'm not seeing? Something I'm missing.
The Onken W cabs sound great, but they don't fit into what we normally think of as "Onken."
Any ideas?
Just plans and construction tips. L'Audiophile must have published formulas at some time - but they must be "Hiding".
The Onken W is an odd beast. I know it well - sounds great - but why is it called Onken? And why W? AFAIK, it is just a big box with 2 small ports, 1 in each upper corner. None of the multiple vents along the sides that we generally think of as an ONKEN/ULTRAFLEX box. What's up with that? Or is there something I'm not seeing? Something I'm missing.
The Onken W cabs sound great, but they don't fit into what we normally think of as "Onken."
Any ideas?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.