Hey zeljkor,
I ran your numbers in the Onken spreadsheet and get much the same thing you do. Small box, long ports. I think your Sd is about right at 890 cm.
Not knowing the exact T/S of the 416A (or the Onken equiv) I tried to reverse engineer it from what I know.
Below is my best guess for the 416-8A which gives a box about the right size and ports of the correct length (I think). Don't know if the 8 or 16 ohm version was used in the boxes I heard.
Fs: 21
Re 6.5
Qms: 6.70
Qes: 0.22
Vas: 1040L
Mms: 61.25g
Sd: 890cm
Rg: 0.3
n= 6.43
Vents
W: 5cm
H: 2.83cm
vents: 6
Svent 849.9
Vb: 332.3L
Vtotal:363.24L
L vent 52.7
L' vent 36.4
This looks about right for the 416A and is the right size for the box. Don't know about vents, tho. The original box has 40cm long vents. I don't understand the difference between "L vent" and L' vent".
Anyway, that puts it in the ballpark for the 416A.
With the much lower Vas of the 416-8C, the box is going to be smaller. The vents seem to get long at the same time.
I ran your numbers in the Onken spreadsheet and get much the same thing you do. Small box, long ports. I think your Sd is about right at 890 cm.
Not knowing the exact T/S of the 416A (or the Onken equiv) I tried to reverse engineer it from what I know.
Below is my best guess for the 416-8A which gives a box about the right size and ports of the correct length (I think). Don't know if the 8 or 16 ohm version was used in the boxes I heard.
Fs: 21
Re 6.5
Qms: 6.70
Qes: 0.22
Vas: 1040L
Mms: 61.25g
Sd: 890cm
Rg: 0.3
n= 6.43
Vents
W: 5cm
H: 2.83cm
vents: 6
Svent 849.9
Vb: 332.3L
Vtotal:363.24L
L vent 52.7
L' vent 36.4
This looks about right for the 416A and is the right size for the box. Don't know about vents, tho. The original box has 40cm long vents. I don't understand the difference between "L vent" and L' vent".
Anyway, that puts it in the ballpark for the 416A.
With the much lower Vas of the 416-8C, the box is going to be smaller. The vents seem to get long at the same time.
Well... maybe not. It depends on the model.
I ran both drivers, the A & the C as a simple bass reflex.
Gave it about 330 liters, and the same port size and length.
The results are very similar, almost identical. The A is a little flatter and shows not quite as much group delay, bit otherwise they are quite close.
Certainly the Onken spreadsheet makes the 416A look better, but standard bass reflex calcs don't.
Any ideas?
I ran both drivers, the A & the C as a simple bass reflex.
Gave it about 330 liters, and the same port size and length.
The results are very similar, almost identical. The A is a little flatter and shows not quite as much group delay, bit otherwise they are quite close.
Certainly the Onken spreadsheet makes the 416A look better, but standard bass reflex calcs don't.
Any ideas?
I'm trying to calculate an onken box for a Celestion FTR15-3070C
http://professional.celestion.com/pro/products/pdf/FTR15-3070C.pdf
using ONKEN_CALC.XLS
With regards to Svent and Sd, the best I can get is Svent 40% less then Sd. One of the condition for an Onken design is that Svent should not be less the 15% of Sd.
What would be the consequence of ignoring that point and allowing the Svent to be 40% less then Sd. What the sound would be?
Would a vented box more a better choice? (eg 167litres Fb 42 Q=6.93
I'll appreciate any comment from anyone.
http://professional.celestion.com/pro/products/pdf/FTR15-3070C.pdf
using ONKEN_CALC.XLS
With regards to Svent and Sd, the best I can get is Svent 40% less then Sd. One of the condition for an Onken design is that Svent should not be less the 15% of Sd.
What would be the consequence of ignoring that point and allowing the Svent to be 40% less then Sd. What the sound would be?
Would a vented box more a better choice? (eg 167litres Fb 42 Q=6.93
I'll appreciate any comment from anyone.
apelizzo said:
This is probably a clear indication that the Onken box design is not a good match for the driver in question. Post the values you used in the Onken calc so that we can see what assumptions you made - if they are reasonable ones then you should probably consider another box design for this driver. My suspicion from a quick glance at the specs is that qts is a little on the high side, and there may be other issues I did not see. (Do you have the drivers or are these just a potential choice?)
The cone mass (Mms/d) seems on the high side for the Onken. Also your Rg seems unrealistically low unless you direct drive the woofer and have no inductor in the X-O. A more realistic value would be on the order of 0.5 - 1 ohm. Clearly you planned on using this Onken box with a solid state amplifier, because if you were using a tube amplifier you would have to add its output source impedance (could be several ohms or more with an SE amp) to that of the wiring and X-O components DCR. In my Onken Rg is slightly over 3 ohms which has a substantial effect on qts. (Deliberately I might add)
The lower Vas seems to be a stumbling block for more modern divers. The original 416A had a Vas of over 1000L, the 416-8A about 700L. They seem to be the best dirvier for the big Onken box.
That said, I've heard the petit onken (12" driver) and the mini Onken (10" Focal) and the Fonken (small Fostex) and they all sounded pretty darn good.
Maybe just reduce box volume to suite Vas? Tune ports to taste?
That said, I've heard the petit onken (12" driver) and the mini Onken (10" Focal) and the Fonken (small Fostex) and they all sounded pretty darn good.
Maybe just reduce box volume to suite Vas? Tune ports to taste?
Thanks guys for your help.
I think I'll give up with the Onken and I will design a Reflex box. It looks like is the safest way to go.
By the way I saw a project where an Onken design is still considered valid as published with Svent 40% less then Sd.
IMO I don't think we can call it Onken and I doubt it can be a good one.
Any thought?
http://www.audiodesignguide.com/HiEff/HiEff.html
Thanks
I think I'll give up with the Onken and I will design a Reflex box. It looks like is the safest way to go.
By the way I saw a project where an Onken design is still considered valid as published with Svent 40% less then Sd.
IMO I don't think we can call it Onken and I doubt it can be a good one.
Any thought?
http://www.audiodesignguide.com/HiEff/HiEff.html
Thanks
It's hard to say - and no one seems to know. Or if they do know, they aren't telling!
Is the Onken/Jensen design just a bass reflex with a certain style of vents, or is it something other? There does not seem to be much agreement.
Then just to confuse things there is the "Onken W" which is a big box with 2 tiny vents. There are only about 12% of Sd.
And it sounds great.
EDIT: I read thru Ciuffoli's design again and he does take a very methodical approach. Well researched, well documented - on paper. But we don't know what it sounds like. We should ask.
Also ran some BR stuff in Unibox using Kevin's suggestions of higher series resistance (tube amp). It does make a very large difference. So maybe we should look at your driver again?
Is the Onken/Jensen design just a bass reflex with a certain style of vents, or is it something other? There does not seem to be much agreement.
Then just to confuse things there is the "Onken W" which is a big box with 2 tiny vents. There are only about 12% of Sd.
And it sounds great.EDIT: I read thru Ciuffoli's design again and he does take a very methodical approach. Well researched, well documented - on paper. But we don't know what it sounds like. We should ask.
Also ran some BR stuff in Unibox using Kevin's suggestions of higher series resistance (tube amp). It does make a very large difference. So maybe we should look at your driver again?
I would appreciate your recommendation regarding the ideal setup for Celestion FTR15-3070C. According to my calculations I have a BS box of 167litres Fb=43Hz F3=44.5Hz QL=7. I have no confidence in Onken calculation.
I built my mini SE tube amp about 3Watts using constant current design as I don't like miss the bass adopting traditional design.
The output transformer has DC resistance of 0.4Ohms. It's a low impedence SE amplifier using triodes only.
Also I would like to get an opinion from experts about the Tractrix horn that Ciuffoli adopts. I could not find any radiation pattern chart about it. What is the basic difference between that Tractrix horn and a CD horn in terms of sound stage off axis radiation and distortion.
As you can see I like Chiuffoli's idea to build a 2 way system like that but it's hard to get answers from him.
All I'm trying to build is an high efficiency system I can use for reference in my tube amp projects as well as an exciting speaker not a flat dead monitor sound.
Thanks
I built my mini SE tube amp about 3Watts using constant current design as I don't like miss the bass adopting traditional design.
The output transformer has DC resistance of 0.4Ohms. It's a low impedence SE amplifier using triodes only.
Also I would like to get an opinion from experts about the Tractrix horn that Ciuffoli adopts. I could not find any radiation pattern chart about it. What is the basic difference between that Tractrix horn and a CD horn in terms of sound stage off axis radiation and distortion.
As you can see I like Chiuffoli's idea to build a 2 way system like that but it's hard to get answers from him.
All I'm trying to build is an high efficiency system I can use for reference in my tube amp projects as well as an exciting speaker not a flat dead monitor sound.
Thanks
panomaniac said:
Oh really?! I've expounded on this a number of times over various forums, though ATM this is the only one that I remember where it is (note that at least one post appears to have been truncated, so unless I saved/can find my originals I don't know what of interest may be missing): http://audioroundtable.com/forum/in...&S=ba5a725f12f995153f2ea3290dbe99c6#msg_18231
Review Thuras's original reflex patent to see the Jensen Ultraflex/Onken's roots. An interesting footnote is that in the patent he states that Sd = Av was used strictly to simplify his electrical equivalent ckt. equations, but somewhere along the line it became 'gospel' as the ideal, so don't lose any sleep over not being able to meet this criteria since it's fine as long as the vents aren't too long to achieve a < ~4% vent mach.
Anyway, I see I lost track of this thread for whatever reason, so will 'catch up' with earlier posts I need to respond to as time permits.
GM
[FONT=Arial, sans-serif]Hi, most information about Onken is in this thread, so this is the proper place to show this idea i guess. [/FONT]
[FONT=Arial, sans-serif]Searching for drivers suitable for Onken style cabinets (Qts 0.3- 0.4, high Vas). I remembered the short ports needed for QB5 highpas basreflex alignments (Qts 0.5 – 0.6, high fs). So i tried to simulate a bassreflex with highpas capacitor as Onken. This is the result with a Celestion TF1218 woofer (65 US$). Halfspace 1 Watt/m[/FONT]
[FONT=Arial, sans-serif]
[/FONT]
[FONT=Arial, sans-serif]Red line without capacitor, blackline with. Volume box 158 liter, port area 470 cm2, lenght port 33 cm, resistance coil, wire & amp 0.3 Ohm. Total volume port included 173.5 liter. Highpass capacitor 2.000 uF, I used these Thielle Small Parameters: LF Pressed Chassis / Ferrite - TF1218 - Celestion - Guitar, Bass & Pro Audio Speakers[/FONT]
[FONT=Arial, sans-serif]Computer say's ok! So did i just find a way to use cheaper high Q and FS drivers in Onken speakers? Or is this just a “monkey with a simulation program” fluke?[/FONT]
[FONT=Arial, sans-serif]Searching for drivers suitable for Onken style cabinets (Qts 0.3- 0.4, high Vas). I remembered the short ports needed for QB5 highpas basreflex alignments (Qts 0.5 – 0.6, high fs). So i tried to simulate a bassreflex with highpas capacitor as Onken. This is the result with a Celestion TF1218 woofer (65 US$). Halfspace 1 Watt/m[/FONT]
[FONT=Arial, sans-serif]
[FONT=Arial, sans-serif]Red line without capacitor, blackline with. Volume box 158 liter, port area 470 cm2, lenght port 33 cm, resistance coil, wire & amp 0.3 Ohm. Total volume port included 173.5 liter. Highpass capacitor 2.000 uF, I used these Thielle Small Parameters: LF Pressed Chassis / Ferrite - TF1218 - Celestion - Guitar, Bass & Pro Audio Speakers[/FONT]
[FONT=Arial, sans-serif]Computer say's ok! So did i just find a way to use cheaper high Q and FS drivers in Onken speakers? Or is this just a “monkey with a simulation program” fluke?[/FONT]
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Onken parameters are a pita! Anyhow after shifting tru my speaker library for usefull QB5 drivers. I found some other cheap drivers with Onken port length beneath 36 cm and "high pass Onken" usability; Tymphany FSL-1015R02-08, Eminence Alpha 10A, Faital Pro 10FE200 and Fane 12-200. All well below the 65 US$. Hope this helps someone who is interested in Onken, but not willing to give up an arm and a leg for a vintage driver with the proper TSP.
At least not a lot of wood and money will be lost if this "high pass Onken alignment" is a computer / monkey fluke.
At least not a lot of wood and money will be lost if this "high pass Onken alignment" is a computer / monkey fluke.
Because i was afraid to glue together a gaint fridge size boombox. I compared the Onken spreadsheet outcome with some other multiport bassreflex calculators. There's a big difference, the Onken calc comes up with longer ports. Comparing the different port lengths Onken seems to be a EBS aka Extended Bass Shelf alignment.
No problem at all if you use a big woofer with a 25 Hz resonance frequency, Qts of 0.30 and a huge Vas, -3 dB will be around 25 Hz and the port tuning will be so low that the extra delay caused by the long port will be in the very low freq's. I don't think these long ports work so well with an Onken tuned to a -3dB point of 40-50 Hz and the higher delay caused by long ports...
Any thoughts on this? Or am i just plain wrong? Any experience?
No problem at all if you use a big woofer with a 25 Hz resonance frequency, Qts of 0.30 and a huge Vas, -3 dB will be around 25 Hz and the port tuning will be so low that the extra delay caused by the long port will be in the very low freq's. I don't think these long ports work so well with an Onken tuned to a -3dB point of 40-50 Hz and the higher delay caused by long ports...
Any thoughts on this? Or am i just plain wrong? Any experience?
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