Allen - long story behind the evolution of the original name, and the naming convention Dave has followed for the dozens of designs since. The "Ken" part refers to a general physical resemblance to "Onken" multiple (high aspect ratio) slot ports, and the format has proven to be flexible over a wide array of enclosure sizes and driver types. The little nScan-Kens (that would be "nano" for size, and "Scan" for brand ) are the tiniest we've yet built - there's less than 260in^2 of 1/2" ply in the pair. The largest to date was for an Eminence 12" that took at least 3 5x5 ft sheets
A "fonken" is a very specific bass reflex alignment where the high ratio vents add an "R" to the vent and make the box less sensitive to the dynamic changes to the T/S parameters.
A picture of an Onken bass enclosure in a late 70s Audax design book was the original inspiration -- alhou they look similar the Fonken-tuning is not the same as an Onken, we only borrowed the vents.
This has proven to produce bass that is very elegantly controlled, althou not the maximum exention possible. Boxes tend to be quite small.
The 1st version of the concept was for the CSS FR125. That was not really a success, but Chris asked if we could put the Fostex FE127 in something similar and that was an out of the park design. That was the original Fonken (name credited to Chris), now called the Fonken Prime since the design technique turned out to be fertile ground.
There are now miniOnken (the generic name -- Fonken is reserved for those boxes with Fostex drivers) for a myriad of drivers from 3" Fostex, Mark Audio, ScanSpeak, to 15" Tannoys. Trying to maintain a somewhat consistent naming scheme has yielded a dizzying array of names.
It was a sad day when my previous Edirol FA66 DAC went down. My backup Edirol USB DAC did not have near the DDR and the system lost a level of performance. At swap-n-shop on Sunday i ran into a fellow selling a TC Konnekt 8, i bought at a bargin price and has brought me back to similar performance as before so i am happy.
I could never afford an expensive DAC but in the highly competitive proAudio field these guys will build at least a 1000 pieces for every single unit the hifi guys sell and they are really good value for the money (this one used cost me $50 CAD (about $40 USD)). They also come with multiple channels out (this one & the FA66 have 4) so i can bi-amp right out of Pure Music, as well as micPres so they can be used for measuring.
dave
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Dayton DATS is a wonderful super useful and accurate tool despite what some may say. I have one and use it almost daily. Measurements often match manufacturer's specs. So differences probably due to variability in drive units. Also works great as LCR meter to measure your xo components precisely. I have measured high tolerance caps, inductors, and 1% resistors and they are spot on. You need a gram scale and some plastic modeling clay to add mass to the cones to do the Vas measurement.
For $100 DATS v2 is now an essential part of my tool box. Oh and I also use it to measure impedance sweeps of a speaker alignment. I used to use REW and my own resistors and cables but find DATS much more convenient and it is tough as my sound card got damaged from doing a sweep on a speaker.
For $100 DATS v2 is now an essential part of my tool box. Oh and I also use it to measure impedance sweeps of a speaker alignment. I used to use REW and my own resistors and cables but find DATS much more convenient and it is tough as my sound card got damaged from doing a sweep on a speaker.
Allen, it's up to you what you spend on gear like that. I'd rather spend the money on a calibrated microphone and just get the DATS for this task.
I did without such a device and rigged up some crude tools that do pretty much the same task. But then I was sure I was going to use EQ and FIR correction (wouldn't dream of going without it really) and I just wanted to get repeatable impedance measurements of all drivers. My DIY rig was good enough for that. It sounds like you are playing with different ideas and rather high crossover points...
Trying to build a FAST array? 🙂
You're almost entering multi way territory here...
I did without such a device and rigged up some crude tools that do pretty much the same task. But then I was sure I was going to use EQ and FIR correction (wouldn't dream of going without it really) and I just wanted to get repeatable impedance measurements of all drivers. My DIY rig was good enough for that. It sounds like you are playing with different ideas and rather high crossover points...
Trying to build a FAST array? 🙂
You're almost entering multi way territory here...
Guess you were lucky with the one you got. Not so for many i have corresponded with. Many have ended upin people's closets
More a measure of how horzontal the T/S curves are.
dave
I have the latest DATS v2 - maybe that is better now. The first unit they shipped me was actually bad (dead input channels) but got it exchanged quickly. It works like a charm now - USB interface is recognized instantly.
Cute-Cubes-Ken
I can not help myself:
Cute 🙂
And I mean this in a good way: The small cabinet size could turn out to be an asset if I do decide to use this driver in a 2-way FAst array.
How did it sound? I imagine it is not at its full potential yet, as I am sure it is not fully broken in. Does it show any promise being run down to 80 Hz?
I can not help myself:
Cute 🙂
And I mean this in a good way: The small cabinet size could turn out to be an asset if I do decide to use this driver in a 2-way FAst array.
How did it sound? I imagine it is not at its full potential yet, as I am sure it is not fully broken in. Does it show any promise being run down to 80 Hz?
If in an array you would not use it in a BR config… EQ in the low end would be restricted to a roll-off below Vb.
Attached are the sealed sims. How much EQ you put into them depends on how low you want to go and how much power you have.
I have some initial impressions but won't do a serious eval until i get some more hours on them. They are good, whether $95 each good i don't know.
Certainly if you needed something really small, quite good, and the $190 in drivers wasn't a game stopper these would certainly be candidates.
dave
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Possibilities....
I am torn between two different approaches:
One is a full-range array ran down to 80 Hz, and using multiple sub-woofers to fill-in the lowest octaves.
Pros: Tall, slim, and small foot print cabinets.
Definite unified and coherent sound.
Cost.
The other is a 2-way FAst array with a cross-over ran somewhere between 150 - 300 Hz. (Any cross-over point above 80 Hz will require a bass line array).
Pros: Clean Impulse and CSD Response down to the lowest octaves.
Large Sd area for bass octaves, yielding a more "caressive" felt bass.
More SPL potential (probability not needed) and Less IM distortion
Less EQ needed
I have also considered maybe building both designs, starting with the full-range array down to 80 Hz. At least I will have something nice to listen to while I am building the FAst version, then when they are both up and running, I will have my 4.2 surround system: FAst in front and Full-range in back. Of course, if I am content with the Full-range version, then I will build a second pair for the surround system. 😀
A lot of this will depend on what I think of the drivers. If it turns out that the Fostex works good down to 80 Hz, yet the 10F has the edge on the highs, sacrificing a little in the bass, then I could build the best of both worlds using both drivers. Granted, this will not happen all at once, but it will be a fulfilling, long term adventure...
I am torn between two different approaches:
One is a full-range array ran down to 80 Hz, and using multiple sub-woofers to fill-in the lowest octaves.
Pros: Tall, slim, and small foot print cabinets.
Definite unified and coherent sound.
Cost.
The other is a 2-way FAst array with a cross-over ran somewhere between 150 - 300 Hz. (Any cross-over point above 80 Hz will require a bass line array).
Pros: Clean Impulse and CSD Response down to the lowest octaves.
Large Sd area for bass octaves, yielding a more "caressive" felt bass.
More SPL potential (probability not needed) and Less IM distortion
Less EQ needed
I have also considered maybe building both designs, starting with the full-range array down to 80 Hz. At least I will have something nice to listen to while I am building the FAst version, then when they are both up and running, I will have my 4.2 surround system: FAst in front and Full-range in back. Of course, if I am content with the Full-range version, then I will build a second pair for the surround system. 😀
A lot of this will depend on what I think of the drivers. If it turns out that the Fostex works good down to 80 Hz, yet the 10F has the edge on the highs, sacrificing a little in the bass, then I could build the best of both worlds using both drivers. Granted, this will not happen all at once, but it will be a fulfilling, long term adventure...
yuck, only a 6db crossover is tolerable to my ears if crossing above 100hz..............
skinny cabs usually equal no midbass unless you add eq (baffle step).
Norman
skinny cabs usually equal no midbass unless you add eq (baffle step).
Norman
Thanks, Dave and Chrisb
Actually, it looks like excursion is going to be the limiting factor. With 30 of these on each side, I am at about 103 dB with the excursions as they are laid out on your sims. It would seem that for the cleanest, most dynamic sound, allowing for head room for dynamic peaks, these are best used in a FAst system crossed at 300 Hz, (ideally at 500 Hz, which is too high). Yet, I know it is hard to judge the true excursion performance off a sim like this, but I prefer to go with the conservative approach at this point in the game.
$95/driver is not necessarily a game stopper if the mid-range and highs are exceptional. Also, considering a FAst set-up, the small cabinet size is a plus. But really, the driver I end up choosing is going to be the one that has what I am looking for in terms of the mid-range and highs.
Dave, do You have a sim done on the same software for the Fostex FF85wk? It would be an interesting comparison...
Thanks for all your efforts and joining in on the adventure...
Allen 😀
I have always preferred sealed over BR. As You have mentioned also, BR seems to be hard to EQ. I have not heard a Ken implemented BR, which I am guessing is more natural due to how the high aspect ratio vents spread the tuning out over a larger area. (I still have not read the original OnKen Document yet, just checking in, after a 15 hour day! 😉)
Actually, it looks like excursion is going to be the limiting factor. With 30 of these on each side, I am at about 103 dB with the excursions as they are laid out on your sims. It would seem that for the cleanest, most dynamic sound, allowing for head room for dynamic peaks, these are best used in a FAst system crossed at 300 Hz, (ideally at 500 Hz, which is too high). Yet, I know it is hard to judge the true excursion performance off a sim like this, but I prefer to go with the conservative approach at this point in the game.
$95/driver is not necessarily a game stopper if the mid-range and highs are exceptional. Also, considering a FAst set-up, the small cabinet size is a plus. But really, the driver I end up choosing is going to be the one that has what I am looking for in terms of the mid-range and highs.
Dave, do You have a sim done on the same software for the Fostex FF85wk? It would be an interesting comparison...
Thanks for all your efforts and joining in on the adventure...
Allen 😀
Attachments
Not quite that far yet...
Getting the cross-over right on the FAst version is definitely a concern I have. And from what I have glanced at from others who have built FAst systems, is they also prefer 1st order cross-overs. Nice thing about DSP in JRiver, I can experiment with this. 🙂
Norman, out of curiosity, have You tried FIR based digital cross-overs?
We will be digging into this more later...
Initially, if using a 3 - 3 1/2" driver for a full-range array, I was thinking of building a 12" - 14" wide baffle with large radius edges. This is still pretty "narrow" if compared to 18" bass bins or 4' X 8' open baffles. My main goal for the baffle and cabinet width is to limit defractions and promote good dispersion. The shapes I have in mind is a tall circular or egg-shaped cylinder (like a pipe), a tall pie-shape (wedge cut out of a pipe), or a tall pentagon. I want to dig in deeper on what different shapes of arcs and bevels do to the sound and dispersion of the drivers. Baffle step is a secondary concern (if a concern at all - see below).
I can see why Derek promotes wall mounting, as that does reinforce the mid-bass, maybe even too much, which is not a bad thing, as it can be tamed with EQ and demand less excursion on the drivers, yielding more headroom. 😀 Likewise, a wider baffle would do the same thing to a lesser extent.
With baffle step -
I may not have this right, but I believe that is only an issue when listening in the far field to point sources and short line arrays. I believe with a true, near field line array, baffle step no longer applies, especially when using conventional drivers. My NSB arrays are 13 inches wide and I do not have a lack of mid-bass. Off-axis, there is a hare too much mid-bass.
I hope Wesayso will chime in with his experience on this also. If I recall correctly, he had plenty of mid-bass in his "Two Towers" arrays, and they are not too wide.
Getting the cross-over right on the FAst version is definitely a concern I have. And from what I have glanced at from others who have built FAst systems, is they also prefer 1st order cross-overs. Nice thing about DSP in JRiver, I can experiment with this. 🙂
Norman, out of curiosity, have You tried FIR based digital cross-overs?
We will be digging into this more later...
Initially, if using a 3 - 3 1/2" driver for a full-range array, I was thinking of building a 12" - 14" wide baffle with large radius edges. This is still pretty "narrow" if compared to 18" bass bins or 4' X 8' open baffles. My main goal for the baffle and cabinet width is to limit defractions and promote good dispersion. The shapes I have in mind is a tall circular or egg-shaped cylinder (like a pipe), a tall pie-shape (wedge cut out of a pipe), or a tall pentagon. I want to dig in deeper on what different shapes of arcs and bevels do to the sound and dispersion of the drivers. Baffle step is a secondary concern (if a concern at all - see below).
I can see why Derek promotes wall mounting, as that does reinforce the mid-bass, maybe even too much, which is not a bad thing, as it can be tamed with EQ and demand less excursion on the drivers, yielding more headroom. 😀 Likewise, a wider baffle would do the same thing to a lesser extent.
With baffle step -
I may not have this right, but I believe that is only an issue when listening in the far field to point sources and short line arrays. I believe with a true, near field line array, baffle step no longer applies, especially when using conventional drivers. My NSB arrays are 13 inches wide and I do not have a lack of mid-bass. Off-axis, there is a hare too much mid-bass.
I hope Wesayso will chime in with his experience on this also. If I recall correctly, he had plenty of mid-bass in his "Two Towers" arrays, and they are not too wide.
Excursion limitations lining up with CSD...
Now let's just say they perform better then the sim suggests, and I ran these "straight", I could cross a bass line in at 160 Hz, using the natural 'almost' Linkwitz-Riley roll-off of the 1.014 liter box. That slope would fall under Norman's "Yuck" category 😱 Derek's Butterworth would be at 170 Hz. If I was really lucky, and somehow this driver was to completely defy the excursion limits of this sim altogether, I would need 8 dB of EQ at 80 Hz to bring this array to the - 6 dB Linkwitz-Riley point to cross to my subs.
For the Fostex, at one watt, the overall SPL with 32 drivers is 101.5 dB. Its - 6 dB point is at 120 Hz in a 1.588 liter box for Butterworth. In that alignment it would need 5 dB of EQ at 80 Hz to cross to the subs. I do not think 1st order at 80 Hz is THX, but it might be fun to try. My guess with this order cross-over, the subs would need to be close to the arrays. If I went with the large 9.245 liter Bessel roll-off, we would only need just under 4 dB of EQ at 80 Hz. Again, this driver would need to completely defy all excursion limitations given on this sim. And not really understanding the Fostex X-max to begin with, it is hard to say where to even cross this driver over in a FAst array (2000 kHz?). If I was to guess that the X-mech is 2 mm, this would be clear and free at 400 Hz and I could push it a little at 300 Hz. If x-mech was as high as 7 mm, it could go down to 140 Hz, but that is probably a pipe dream. (I will not be going higher then 300 Hz with either driver).
I do not know how close to reality these excursion estimates are on these sims, but I find it interesting when considering that the CSD response on both of these drivers falls apart at about the same frequencies their excursion limits are reached. (I am doing a conservative "guess" with the Fostex.) I do not think that is a coincidence. And as I mentioned earlier, it does appear the Fostex is a little cleaner between 300 - 400 Hz; note that it does not move as much at these frequencies as the 10F (even though it is "outside" its "published" X-max). It is going to be interesting to see how the 10F performs against the Fostex in the Mids and Highs.
I am agreeing more with Derek on this, "I believe in minimising cone travel by maximising surface area."
On one hand, I probably could run both of these drivers safely down to 100 Hz (10F needing more EQ, at least twice the power (for EQ)), and have a "reasonable" amount of distortion and power compression. 80 Hz seems to be out of the question with these driver choices.
Yet, if I really wanted to keep things clean, relaxed, open and as free as possible of IM distortion, esp with dynamic peaks, I would need to embark on the challenge of integrating a bass line and hopefully not having the "yuck" Norman is talking about. If avoiding the "yuck" is as simple as 1st order cross-overs, we have it made! 🙂
It looks like the trade off is the simplicity and lower cost of the Full-Range Array, verses the technically superior, lower distortion FAst Array. But I have heard speakers that measured really well and sounded terrible, so we will see where this adventure goes...
I should try punching in the Tectonic into one of these sims, see where that comes out.
Allen
That is the concern. On the positive note, if I was to use 30 10Fs/channel and achieve 103 dB SPL @ 1 watt, I would not need a big amp. 😉 But to have no power compression at all, these would need to be crossed at 500 Hz (based on x-max), I would push the envelope and go for 300 Hz (based on x-mech).
Now let's just say they perform better then the sim suggests, and I ran these "straight", I could cross a bass line in at 160 Hz, using the natural 'almost' Linkwitz-Riley roll-off of the 1.014 liter box. That slope would fall under Norman's "Yuck" category 😱 Derek's Butterworth would be at 170 Hz. If I was really lucky, and somehow this driver was to completely defy the excursion limits of this sim altogether, I would need 8 dB of EQ at 80 Hz to bring this array to the - 6 dB Linkwitz-Riley point to cross to my subs.
For the Fostex, at one watt, the overall SPL with 32 drivers is 101.5 dB. Its - 6 dB point is at 120 Hz in a 1.588 liter box for Butterworth. In that alignment it would need 5 dB of EQ at 80 Hz to cross to the subs. I do not think 1st order at 80 Hz is THX, but it might be fun to try. My guess with this order cross-over, the subs would need to be close to the arrays. If I went with the large 9.245 liter Bessel roll-off, we would only need just under 4 dB of EQ at 80 Hz. Again, this driver would need to completely defy all excursion limitations given on this sim. And not really understanding the Fostex X-max to begin with, it is hard to say where to even cross this driver over in a FAst array (2000 kHz?). If I was to guess that the X-mech is 2 mm, this would be clear and free at 400 Hz and I could push it a little at 300 Hz. If x-mech was as high as 7 mm, it could go down to 140 Hz, but that is probably a pipe dream. (I will not be going higher then 300 Hz with either driver).
I do not know how close to reality these excursion estimates are on these sims, but I find it interesting when considering that the CSD response on both of these drivers falls apart at about the same frequencies their excursion limits are reached. (I am doing a conservative "guess" with the Fostex.) I do not think that is a coincidence. And as I mentioned earlier, it does appear the Fostex is a little cleaner between 300 - 400 Hz; note that it does not move as much at these frequencies as the 10F (even though it is "outside" its "published" X-max). It is going to be interesting to see how the 10F performs against the Fostex in the Mids and Highs.
I am agreeing more with Derek on this, "I believe in minimising cone travel by maximising surface area."
On one hand, I probably could run both of these drivers safely down to 100 Hz (10F needing more EQ, at least twice the power (for EQ)), and have a "reasonable" amount of distortion and power compression. 80 Hz seems to be out of the question with these driver choices.
Yet, if I really wanted to keep things clean, relaxed, open and as free as possible of IM distortion, esp with dynamic peaks, I would need to embark on the challenge of integrating a bass line and hopefully not having the "yuck" Norman is talking about. If avoiding the "yuck" is as simple as 1st order cross-overs, we have it made! 🙂
It looks like the trade off is the simplicity and lower cost of the Full-Range Array, verses the technically superior, lower distortion FAst Array. But I have heard speakers that measured really well and sounded terrible, so we will see where this adventure goes...
I should try punching in the Tectonic into one of these sims, see where that comes out.
Allen
You will have no problem reaching 80 Hz with the 10F, believe me. There are other problems if you do though... hope to bring more on that soon. But SPL limits out to 80 Hz are no concern. Like my simple WinISD Sim showed you'd be able to use 70 watt on the 10F with 25 drivers, but that includes the EQ. What WinISD is not showing it extra gain you'll be getting on the low end and the drop off due to comb filtering on the high end.
I have no lack of output in the mid bass with my slim towers. They are close to the back wall though, as intended.
I have no lack of output in the mid bass with my slim towers. They are close to the back wall though, as intended.
Opps, math error...
I got the sensitivity wrong on the post above:
It is not 103 dB @ 1 watt for the 10F array or 101 dB @ 1 watt for the Fostex array. The formula for the correct sensitivity is in James Griffen's White Paper, I will look it up later when I am not so sleepy. For now, I am satisfied with the 70 watt figure Wesayso provided. 🙂
The point I wanted to get across is the excursion of the singular 10F driver at 89 dB will not be reached in a 30 driver array until it reaches 103 dB. Likewise for the Fostex.
This is what we need to dig into when You are ready. You do not foresee any issues in power compression or IM distortion?
It would help if I really knew how LOUD I listen especially in terms of dynamic peaks. I have never measured my listening levels with a SPL meter.
I got the sensitivity wrong on the post above:
It is not 103 dB @ 1 watt for the 10F array or 101 dB @ 1 watt for the Fostex array. The formula for the correct sensitivity is in James Griffen's White Paper, I will look it up later when I am not so sleepy. For now, I am satisfied with the 70 watt figure Wesayso provided. 🙂
The point I wanted to get across is the excursion of the singular 10F driver at 89 dB will not be reached in a 30 driver array until it reaches 103 dB. Likewise for the Fostex.
This is what we need to dig into when You are ready. You do not foresee any issues in power compression or IM distortion?
It would help if I really knew how LOUD I listen especially in terms of dynamic peaks. I have never measured my listening levels with a SPL meter.
I listened to a Rodrigo & Gabriella's song called "Atman" the other day and decided to get out the SPL meter as it seemed kinda loud, can only tell when trying to talk (lol)... I was running at ~96 dB(!) at the listening position. 😱 Sounded awesome though... not much bass in there so no problems. It does hit around 60 Hz though (and hard). I still hardly see the cones move...
Couldn't catch the right moment but gives you an idea.
I only have a 100 watt amp so I need to watch that. The lines would take 240 watt in my case before running out of excursion.
I'll clip my amp before reaching that. You also need to watch the level of gain within JRiver. Cant use too much with considerable EQ.
I know what it sounds like when I clip that...
But I don't see reaching 80 Hz as a problem, SPL wise.
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Interesting variety of opinions here...
There has always been mixed reviews on the DATS, but I have heard the v2 version is better.
I would build probes to hook into my M-audio XLR mic, but I do not want to chance an accident like what X experienced.
I do want my arrays overall matched to each other, but I do not know if I need to measure each individual driver to achieve that (although I would know for sure if I did). Also, I would like to have something to measure the impedance curve, as I know that is a very useful tool.
Looks like I really do not need to hurry if I am building off the manufacturers specs.
Now if I was to get into driver development then a crazy expensive one like what Derek suggested would be needed.
I will need to think about how far into this type of development I will need to go...
I don't think you need to worry about a driver's CSD in the 400Hz and below region - room reflections will dominate anything the driver has there unless you are listening in an anechoic chamber.
I don't think 80Hz will be an issue given Wesayso's lines have drivers with same xmax and lower sensitivity and 5 fewer drivers. How were you going to wire 30 drivers up? 5 series in 6 parallel?
For 6dB/octave crossovers in FAST look at my 10F/RS225 thread to see how tricky that is to do well at a low XO of 350Hz. If you want transient perfect steps like Wesayso, best to go full range like Wesayso - he hits 30Hz no problem with his array. If you integrate a sub, be prepared to work hard on matching the phase at the XO. A lot of work as I am finding out.
I don't think 80Hz will be an issue given Wesayso's lines have drivers with same xmax and lower sensitivity and 5 fewer drivers. How were you going to wire 30 drivers up? 5 series in 6 parallel?
For 6dB/octave crossovers in FAST look at my 10F/RS225 thread to see how tricky that is to do well at a low XO of 350Hz. If you want transient perfect steps like Wesayso, best to go full range like Wesayso - he hits 30Hz no problem with his array. If you integrate a sub, be prepared to work hard on matching the phase at the XO. A lot of work as I am finding out.
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