Locally there is a firm which is short of IT staff. They go out to the school to search for talent. They select only those who have not (!) had exposure to computer games, iPad etc. during their childhood since computer exposure at too young an age kills analytical skills. (unable to think for themselves)
AFAIK the FX120 is still in production. It's used in the Von Schweikert Unifield 3 speaker system:
http://www.diyaudio.com/forums/mult...ield-3-offshoot-fullranger-helper-woofer.html
In stock at Madisound. The Madisound Speaker Store
jeff
FX200 went by the board, but the FX120 does still seem to be soldiering on, and remains one of Fostex's best drive units. Not cheap, but an excellent performer for what it is.
Hello guys. I have just finished reading the entire thread, plus many more similar ones, but I am still nowhere near enough having a clear decision in my mind.
Currently I am using a set of PBN Montana EPSignatures (the previous series) powered by an LM3785 gainclone.
As you might have guessed, I am more and more drawn to the low watt SET amplifying philosophy, and while my 92dB @ 4ohm beasts still sound very nice with the 30W AB amps, my next step into VFET powered 10W SET awesomeness is probably going to be a problem.
Plus my friends' rigs that are using SET powered 15" and 8" Tannoy and Altec concentrics are not cutting me any slack, feeding my ears with very nice music.
I was initially thinking about the FHMK3 or the new FHXL, but truth is that I have only one usable corner for loading, plus I would love to have a bigger driver to retain some of the punchy bass that I am used to.
On the other hand, the Metronome sounds like a nicer idea. It can support bigger units, and is more aesthetically pleasing than those big ugly washing machine type of enclosures that we see with bigger units.
So my parameters currently are 8Ohms impedance, 93db+ sensitivity, and at least an 8" driver to be able to move some bassy air, while keeping the drive as free as possible from passive crossover components.
Size is not a big deal since my current speakers are already ~6 feet tall and I do not mind expanding a bit on width.
I would appreciate any suggestions for trusted and tried solutions that fit my requirements.
My completely uneducated thoughts so far were towards the AN coaxial speakers, mostly because I am very much biased by my sonic and aesthetic experience from tannoys and altecs (I know I know... not even close).
Other than that, Steve's FF225WK + Monacor implementation seems promising, although that fostex is a bit UGLY 😛
Budget wise, I would like to stay beneath 5-600 dollars or even a bit higher if it is something that would really make a difference.
Thanks a lot for your time.
Currently I am using a set of PBN Montana EPSignatures (the previous series) powered by an LM3785 gainclone.
As you might have guessed, I am more and more drawn to the low watt SET amplifying philosophy, and while my 92dB @ 4ohm beasts still sound very nice with the 30W AB amps, my next step into VFET powered 10W SET awesomeness is probably going to be a problem.
Plus my friends' rigs that are using SET powered 15" and 8" Tannoy and Altec concentrics are not cutting me any slack, feeding my ears with very nice music.
I was initially thinking about the FHMK3 or the new FHXL, but truth is that I have only one usable corner for loading, plus I would love to have a bigger driver to retain some of the punchy bass that I am used to.
On the other hand, the Metronome sounds like a nicer idea. It can support bigger units, and is more aesthetically pleasing than those big ugly washing machine type of enclosures that we see with bigger units.
So my parameters currently are 8Ohms impedance, 93db+ sensitivity, and at least an 8" driver to be able to move some bassy air, while keeping the drive as free as possible from passive crossover components.
Size is not a big deal since my current speakers are already ~6 feet tall and I do not mind expanding a bit on width.
I would appreciate any suggestions for trusted and tried solutions that fit my requirements.
My completely uneducated thoughts so far were towards the AN coaxial speakers, mostly because I am very much biased by my sonic and aesthetic experience from tannoys and altecs (I know I know... not even close).
Other than that, Steve's FF225WK + Monacor implementation seems promising, although that fostex is a bit UGLY 😛
Budget wise, I would like to stay beneath 5-600 dollars or even a bit higher if it is something that would really make a difference.
Thanks a lot for your time.
The FF225WK in a five foot cabinet is a great sounding combination, with the
Monacor ribbon tweeter.
Monacor ribbon tweeter.
I m still haunted by that image... Perhaps with a single driver for a less beastly creature.... Those BM15CX38 P-Audios seem to have some good reviews when properly crossed...
Steve do you mind sharing the dimensions? If I m not mistaken it is the 207 plans slightly modified?
I have owned 2 pairs of AN drivers, the super 12 and the super 8 (No coaxials) and I can safely say they sound nothing like the Tannoys.
The ANs are edgy very shouty drivers, high frequencies just rip my ears to shreds.
The extremely low x-max (1mm), low Qts and high VAS also makes them quite a handful to design cabinets around.
You usually end up with huge cabinets and drivers that bottom out at the slightest wiff of sub 80hz bass.
On the other hand, I've built FF165WK metronomes and they sound great, a little laid back on the high frequencies, but great bass from such a tiny driver.
The FH mk3 are great speakers too, and with alpair 7 drivers (or alpair 10 for the FHXL), don't really need full corner loading.
I've been listening to a pair of Alpair 7 FH mk3 for the past couple of months and they sound great with next to zero corner loading. They just can't play deep bass at a constant 95db, but that's to be expected.
Hope it helps.
The ANs are edgy very shouty drivers, high frequencies just rip my ears to shreds.
The extremely low x-max (1mm), low Qts and high VAS also makes them quite a handful to design cabinets around.
You usually end up with huge cabinets and drivers that bottom out at the slightest wiff of sub 80hz bass.
On the other hand, I've built FF165WK metronomes and they sound great, a little laid back on the high frequencies, but great bass from such a tiny driver.
The FH mk3 are great speakers too, and with alpair 7 drivers (or alpair 10 for the FHXL), don't really need full corner loading.
I've been listening to a pair of Alpair 7 FH mk3 for the past couple of months and they sound great with next to zero corner loading. They just can't play deep bass at a constant 95db, but that's to be expected.
Hope it helps.
Yeah pretty much what I have been reading all around the place. The ANs were a completely uneducated guess, highly biased by the size of the drivers, mostly led by the male impulse towards bigger stuff 🙂
I am currently leaning towards Steve's implementation
I am currently leaning towards Steve's implementation
A question about the design. From what I have understood, what is defining this design is the overall area of the top which is less than that of the bottom end. There is however some slack into changing their actual width and depth, moving away more from the golden ratio that I see in their dimensions, as long as the cross-section area remains the same. For example if our actual driver's frame is bigger in diameter and does not fit in the front baffle. I think Dave has illustrated such a change for a Fostex in a post.
What I wanted to ask is if it is important to keep both width and depth of the top end smaller than the respective ones of the bottom end.
Is this a requirement for the proper function of the cabin, or just something aesthetic or a means to eliminate parallel walls?
Because if not, then keeping the depth the same up and down should make the cabin significantly easier to build, and will allow the driver to look directly to the sweet spot instead of looking up, possibly improving the high frequency response too.
And is there a minimum for the depth to minimize reflections or interference of the driver with the back wall?
Sorry for my many questions, I am just working on the details on how I am going to actually continue with actually building this.
What I wanted to ask is if it is important to keep both width and depth of the top end smaller than the respective ones of the bottom end.
Is this a requirement for the proper function of the cabin, or just something aesthetic or a means to eliminate parallel walls?
Because if not, then keeping the depth the same up and down should make the cabin significantly easier to build, and will allow the driver to look directly to the sweet spot instead of looking up, possibly improving the high frequency response too.
And is there a minimum for the depth to minimize reflections or interference of the driver with the back wall?
Sorry for my many questions, I am just working on the details on how I am going to actually continue with actually building this.
Last edited:
Yes, in theory, the top area would be calculated same as for a conical horn for the specific driver, but AFAIK neither the original nor any of its variants are based on any specific horn design theory.
The main thing with the Metronome is that it's a conical expansion, i.e. has no parallel walls. As such, 'golden' or acoustic ratios don't apply, though in theory the expansion should be at least 12 deg. [included] to ensure a smooth, rapid decay of 'slap' echo, same as required in a cinema or sound stage, etc., or horn for that matter, but this isn't practical for most tower speaker alignments.
Minimum depth has been much debated and provided enough damping is required, then the motor can even be flush with the rear cover, though a vent hole would of course be required if the motor has a rear vent.
That said, Altec recommended a 1.5x driver depth for a typical woofer/whatever.
Today, we calculate it based on the 1/2 WL distance between the diaphragm and parallel wall and since the Metronome has none, it's not an issue beyond not restricting the Metronome’s ½ WL pipe action too much, so AFAIK the 1.5x rule-of-thumb minimum should be sufficient.
GM
The main thing with the Metronome is that it's a conical expansion, i.e. has no parallel walls. As such, 'golden' or acoustic ratios don't apply, though in theory the expansion should be at least 12 deg. [included] to ensure a smooth, rapid decay of 'slap' echo, same as required in a cinema or sound stage, etc., or horn for that matter, but this isn't practical for most tower speaker alignments.
Minimum depth has been much debated and provided enough damping is required, then the motor can even be flush with the rear cover, though a vent hole would of course be required if the motor has a rear vent.
That said, Altec recommended a 1.5x driver depth for a typical woofer/whatever.
Today, we calculate it based on the 1/2 WL distance between the diaphragm and parallel wall
GM
Yes
You will probably find that impractical. BTW, this is essentially what Demetri is (with a fold)
dave
The cabinet was designed from the very beginning to have no parallel walls, hence the quadratic taper, but there is room for manoeuvre as Dave above says.
Despite how it appears, and we have been down this road too many times already in this thread, the four sides are all butt joints; spot on 90 degrees.
Colin my my carpenter friend, who built the cabinets I use, even used an engineer's square to demonstrate this fact at a meeting, but still people would not believe the evidence of their own eyes.
If you want to mitre the corners however, the angles are of course compound, but the error is negligible if you use straight 45 degree edges.
The cab is best assembled with all four sides offered up dry. The top and bottom angles are then trimmed so that it stands square on the ground and the top is made level. Then a top cap can be cut and planed to shape before being attached.
The base baffle of course needs angled edges so that it sits squarely in the opening, at the right distance into the mouth of the horn.
The shape is what makes this speaker what it is. Change the shape and WAF is gone
Sounds to me like you could be talking yourself out of this design. 😉
Just build as is. Satisfaction is guaranteed, I promise.
Despite how it appears, and we have been down this road too many times already in this thread, the four sides are all butt joints; spot on 90 degrees.
Colin my my carpenter friend, who built the cabinets I use, even used an engineer's square to demonstrate this fact at a meeting, but still people would not believe the evidence of their own eyes.
If you want to mitre the corners however, the angles are of course compound, but the error is negligible if you use straight 45 degree edges.
The cab is best assembled with all four sides offered up dry. The top and bottom angles are then trimmed so that it stands square on the ground and the top is made level. Then a top cap can be cut and planed to shape before being attached.
The base baffle of course needs angled edges so that it sits squarely in the opening, at the right distance into the mouth of the horn.
The shape is what makes this speaker what it is. Change the shape and WAF is gone
Sounds to me like you could be talking yourself out of this design. 😉
Just build as is. Satisfaction is guaranteed, I promise.
Last edited:
You named a speaker after me? How sweet!!! 😛
To be honest I like fiddling with stuff and making them fit my own madness 🙂
Most of the time they end up too complicated and I abandon them because I do not get the results I was expecting 😛
I was even contemplating making a 3 sided one. That is with 3 sides glued together at 60 degrees, basically making the top/bottom areas a triangle. Bye bye back wall reflections, it should be more sturdy, the holey brace would have to be "sharpened" at 60 degrees to fit in the corner. Hello more awesome look 🙂 Not to mention that I always liked how easy it is to level 3 feet stuff.... speakers, racks, turntables...
Anyway... I will stick to the plan as it is for now 🙂
In the meantime, I did some rough drawings, and it seems that the FF225wk only marginally fits the front baffle at the specified Zd (30/762).
Steve would it be too much to ask you to please measure the top and bottom width of your front baffle? It seems that Colin has modified the ratio a bit and I really like how yours looks. Especially with the tweeter in there. Thanks again
OK,
Top is 5 and a quarter inches
Bottom is 14 and one eighth inches
Metric:
Top 135mm
Bottom 360mm
Steve
Triangular would be interesting🙂
Top is 5 and a quarter inches
Bottom is 14 and one eighth inches
Metric:
Top 135mm
Bottom 360mm
Steve
Triangular would be interesting🙂
Last edited:
Perfect 🙂 Thanks 🙂
I will do some more drawing now and dream about how they are going to look... 🙂
By the way, if someone is thinking about the 3sided one, here are the measurements I calculated.
Bottom:
Front baffle width: 500mm
Side walls: 448mm
Top:
Front width: 200mm
Side walls: 92.3mm
Side walls glued at the back at 90 degrees. Front baffle is glued at 45 degrees.
Multiply by 0.254 to convert to inches
No idea if the magnet is going to fit in there, but a suprabaffle should solve this 🙂
We can even make it thick enough to allow the side walls to support the magnet without the need for a holey brace 🙂
I will do some more drawing now and dream about how they are going to look... 🙂
By the way, if someone is thinking about the 3sided one, here are the measurements I calculated.
Bottom:
Front baffle width: 500mm
Side walls: 448mm
Top:
Front width: 200mm
Side walls: 92.3mm
Side walls glued at the back at 90 degrees. Front baffle is glued at 45 degrees.
Multiply by 0.254 to convert to inches
No idea if the magnet is going to fit in there, but a suprabaffle should solve this 🙂
We can even make it thick enough to allow the side walls to support the magnet without the need for a holey brace 🙂
Last edited:
About the terminus, is it possible to adjust its imperial diameter / length combination (3/1.5 inches or 7.62/38.1mm), to something that fits more metric available diameters, for example 70mm or something with different length? Just asking because it should be super easy to find a metric PVC tube. But for 3inches I would have to order from abroad.