It's not that the arbitrary maximum vent length is exceeded by a little bit - the vent lengths often come out to over two feet so in order to build the box to the proper volume, you could end up with a baffle too small to accommodate the driver, if Rg is realistically maintained.
John
Hi John
Which driver is this with? I was able to get something workable although ridiculously large with the 515-8C and the 8G works very well indeed. It was possible to get vent lengths of 13" or so - just under the limit.
Changing the N number over a range of ~ 5.5 - 6.5 allows you some flexibility in conjunction with tinkering Rg..
I originally wanted to use the 414-8C and started with Sv = Sd, the so-called "best" alignment of 5.7 and a bi-amped system with an Rg of .5Ω. This resulted in a corrected vent length of over two feet and a box volume of 3.3 cubic feet. Using a fairly conventional slot dimension of 1.5" x 6.5" (four on each side) leaves a baffle width of less than 8". Obviously you can fudge the numbers to get something build-able, but what's the point if compromising that much strays so far from the ideal calculated enclosure size?
John
John
Last edited:
Can you post the spreadsheet with the 414-8C params?
Have you tried the Onken tuning @ 6.34 to see what impact that has, and you could also increase Rg to as much as 2 ohms or more at the penalty of some efficiency, but it would probably push the box size in the right direction. My Rg incidentally is in the vicinity of 3 ohms and I would not be afraid to try a little higher - I think GM could elaborate on this vein more clearly than I can.
Have you tried the Onken tuning @ 6.34 to see what impact that has, and you could also increase Rg to as much as 2 ohms or more at the penalty of some efficiency, but it would probably push the box size in the right direction. My Rg incidentally is in the vicinity of 3 ohms and I would not be afraid to try a little higher - I think GM could elaborate on this vein more clearly than I can.
You're welcome!
Browsing the various 'Econowave' threads across several forums may turn up something. Ditto other Petite or even single 414 cab builders as there's been quite a few builds posted over the years.
For vintage, I only know of one choice that has some documentation available, though you may have to 'sweet talk' a 9849 owner into detailing the XO for you to DIY, then swapping in some different component values if 16 ohm is required (click on images to blow up): 9849-8A-8D
832 horn (preferably the early alum.)/802D if 16 ohm, 802-8D/8 ohm, either preferably with GPA's 'HIFI' diaphragm, so leave room to mount it above the 414. Baffle cutout, spacing to 414: http://www.lansingheritage.org/images/altec/plans/1970's-lf-plans/enclosures20.jpg
Last, but not least is to pair it to an 811/802 perched on top and adapt the 9844's XO to a single 414: 9844
GM
Dunno, I'm going strictly by what several seemingly knowledgeable folks posted on the basslist back when the Onken became known to a much wider DIY audience. You're one up on me, I didn't know they also made compression drivers. Got any pics, details?
GM
As you can see, changing the alignment to 6.34 reduces Lv by only 2 1/2".
View attachment Onken 414-8C.numbers.zip
John
Hi John,
Could you post this as a zipped xls file when you have a moment? (No rush) I run Linux and can't open the xml file in the archive you posted. (It opens in my text editor.)
Possibly tomorrow I will just plug the TS params into my spreadsheet if you can point me to the specific maker of the 414 you are planning on using or post the raw 414-8C ts params here. I'm just curious to see what numbers get spewed out as the petit onken as memory serves was designed around a 414...
I wish I could, but I have an Apple computer (which is why had to ask for help on the le Cleac'h and Hornresp calculators 
). I get my data from these websites:
Altec Thiele-Small Parameters
Driver database
John
). I get my data from these websites:Altec Thiele-Small Parameters
Driver database
John
Last edited:
Well, FWIW, the various 414 specs I have all sim about the same in the Petite which has ~20.32" long vents and this pair of 414-8C measured by Cyr-Marc works with 80% vents/n = 6.34:
Speaker A Value Speaker B
6.58 Re 6.31
36 Fs 34
.3070 Qts .2907
.3242 Qes .3156
5.7860 Qms 3.6853
192.97 Vas (l3) 215.8
40.25 Mmd (gr) 40.35
.532 Sd (m3) .532
13.59 Bl 13.13
96.28 dB 1w/m 96.13
97.22 dB 2,83v 97.27
WRT minimum vent area, there's a point of rapidly diminishing returns above the value Richard Small (the 'S' in T/S) determined that post dates the Onken alignment, so to my way of thinking it should set the minimum. For sure it has served me and many others well in reflex apps:
Regardless, what you're trying to design is a maximally flat alignment using a low Qts driver = small cab tuned high which is best realized by designing it with a T/S program at < 5% vent mach = long vent, ergo multiple vents will be even longer.
GM
Speaker A Value Speaker B
6.58 Re 6.31
36 Fs 34
.3070 Qts .2907
.3242 Qes .3156
5.7860 Qms 3.6853
192.97 Vas (l3) 215.8
40.25 Mmd (gr) 40.35
.532 Sd (m3) .532
13.59 Bl 13.13
96.28 dB 1w/m 96.13
97.22 dB 2,83v 97.27
WRT minimum vent area, there's a point of rapidly diminishing returns above the value Richard Small (the 'S' in T/S) determined that post dates the Onken alignment, so to my way of thinking it should set the minimum. For sure it has served me and many others well in reflex apps:
Regardless, what you're trying to design is a maximally flat alignment using a low Qts driver = small cab tuned high which is best realized by designing it with a T/S program at < 5% vent mach = long vent, ergo multiple vents will be even longer.
GM
I just noticed this thread and have a question thats been on my mind for awhile. Ive got a pair of 414z that I would like to use. Ive been vacillating between several options and cant decide what to do. The gist of it is that the 414z seems to be called bass shy by many. I havent listened to mine except in the Coronado cabinets they came in. I wasnt impressed with the LF response.
Will the Onken preclude the use of a sub or is one manditory for these drivers regardless of the enclosure. If this is the case, does it make sense to build a Petite Onken, which I think are generally cool, or a 614 which is the recommended Altec box? Or should I just put them in small sealed/vented boxes and add subs?
I really what to get the best from these drivers so what to do?
amt
Will the Onken preclude the use of a sub or is one manditory for these drivers regardless of the enclosure. If this is the case, does it make sense to build a Petite Onken, which I think are generally cool, or a 614 which is the recommended Altec box? Or should I just put them in small sealed/vented boxes and add subs?
I really what to get the best from these drivers so what to do?
amt
With such a low Qts, it won't do bass with any authority without being either coupled to a matching impedance amp (DF = 1) or a huge BLH, so short of a few pipe organ symphonies and movie LFE, I doubt you'll feel the need for a sub system.
The Petite is a severely under-damped alignment designed for a high output impedance amp, so while it could work well with a sub it would ideally need both its cab and vents heavily damped, so might as well build a sealed cab of the same size and paint vent slots on it.
The 614 is tuned higher, so not as under-damped, but its 4th order roll-off means an XO point around an octave above its ~42 Hz Fb, so a typical 80 Hz XO seems OK.
A typical 120 Hz XO could probably be used with a max flat sealed alignment, so if multiple subs are used, then this is probably the best choice overall.
Anyway, 'best' is a floating target depending on the needs of the app.
GM
The Petite is a severely under-damped alignment designed for a high output impedance amp, so while it could work well with a sub it would ideally need both its cab and vents heavily damped, so might as well build a sealed cab of the same size and paint vent slots on it.
The 614 is tuned higher, so not as under-damped, but its 4th order roll-off means an XO point around an octave above its ~42 Hz Fb, so a typical 80 Hz XO seems OK.
A typical 120 Hz XO could probably be used with a max flat sealed alignment, so if multiple subs are used, then this is probably the best choice overall.
Anyway, 'best' is a floating target depending on the needs of the app.
GM
I'm right either way depending on how one chooses to view it and/or use it to make a specific point, but without a response plot it is confusing and frankly had forgotten having already mentioned it.
Anyway, it's over-damped in that the cab is tuned low enough that the driver's low Qts governs its roll off slope between F3, Fb with a critically damped 0.5 Qts being the line between over (< 0.5) and under (>0.5) damped.
It's under-damped in the sense that the cab is much too large to maintain its over-damped state to Fb, i.e. it has a huge peak at Fb that will 'ring' due to excessive high Q group delay if some form of series resistance isn't used to 'pump up'/flatten out its response.
GM
Anyway, it's over-damped in that the cab is tuned low enough that the driver's low Qts governs its roll off slope between F3, Fb with a critically damped 0.5 Qts being the line between over (< 0.5) and under (>0.5) damped.
It's under-damped in the sense that the cab is much too large to maintain its over-damped state to Fb, i.e. it has a huge peak at Fb that will 'ring' due to excessive high Q group delay if some form of series resistance isn't used to 'pump up'/flatten out its response.
GM
Attachments
So if I use a SET with 16ohm taps, would the Onken or 614 grab another octave or add some dbs at the bottom? My other concern is that the Onken is quite alot of work and lumber so if it doesnt honestly outperform the 614, Id rather forego the extra hassle. I suppose Im still not sure what performance characteristics the Onken offers over a standard BR.
The sealed box w/ qtc .71 may be the easiest way to go. Add a pair of subs with cheap SS power and be done. Although I have to admit there is just something special about being able to use a single low watt amp to power a simple pair of speakers that cover it all.
Yes I have. I sold my 811b horns and decided to go the EW route. Unfortunately the QSC horn has been discontinued so Im waiting for PE to hopefully pick it up (this is the rumor anyway) The CD will be a B&C rather than the BMS since I already have most of what the XO requires and the drivers are less costly. The DE250 seems to be well liked so...
amt
Some nice photos in this thread:
Onken - Audio Voice Acoustics
Some in action in this system, as well as what I believe are Onken multicell horns:
http://haute.fidelite.com.online.fr/Visite-gorm-rug/visite-gorm3.html
I'm still digging for any photo or reference to a woofer.
I lied, I'd forgotten JM's Onken drivers, etc..
The sheet metal 311 (511?) adaptations are interesting plus maybe these cabs were Onken made and the design Hiraga built or at least used as a guideline: Google Translate
GM
The sheet metal 311 (511?) adaptations are interesting plus maybe these cabs were Onken made and the design Hiraga built or at least used as a guideline: Google Translate
GM
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.