Hello!
There are lot of info spread around in different topics about those drivers, I will post all my questions here in one topic.
1. I only want to build a sealed cabinet not vented. I am after that "old school" 60's "huge/live/open" sound and feel.
2. One option is to build something similar to this: Fane 12-250TC Retro Speaker. - Page 2 - audio-talk Has anyone built something similar but with 15 inch driver?
3. Someone here in diyaudio said that to hear the difference between 12 and 15, the cabinet for the 15 needs to be at least twice as big, for example 225 litres. Is that true? What f3 would 15 incher achieve with 100L and with 225L sealed cabinet? I read somewhere that 12 in a 80L sealed cabinet gives f3 around 64hz.
4. How much does cabinet shape affect sound with drivers and enclosures this big? I would like to build something higher and thinner, is that a bad idea?
There are lot of info spread around in different topics about those drivers, I will post all my questions here in one topic.
1. I only want to build a sealed cabinet not vented. I am after that "old school" 60's "huge/live/open" sound and feel.
2. One option is to build something similar to this: Fane 12-250TC Retro Speaker. - Page 2 - audio-talk Has anyone built something similar but with 15 inch driver?
3. Someone here in diyaudio said that to hear the difference between 12 and 15, the cabinet for the 15 needs to be at least twice as big, for example 225 litres. Is that true? What f3 would 15 incher achieve with 100L and with 225L sealed cabinet? I read somewhere that 12 in a 80L sealed cabinet gives f3 around 64hz.
4. How much does cabinet shape affect sound with drivers and enclosures this big? I would like to build something higher and thinner, is that a bad idea?
In order:
1. Fair enough. Remember though that those 'huge' (these things being relative) sealed 1950s - '60s era sealed boxes were often on the order of about 18ft^3, or 500 litres [nearly] if you prefer metric, like some wild modern enthusiast.
2. No idea, but in that volume it may have some compression issues / sound a mite 'choked' unless you can bleed off some pressure.
3. Assuming Butterworth for the purposes of a direct comparative baseline, about 19x larger actually, although you can get ~'near enough' with about 3.5x larger. It's the last few percentage points that take the greatest increases. F3 is largely a meaningless figure in practical use, F6 and to a point F10 are more valuable. However, in 100 litres, you'd have a Qtc of just over 1.0 depending on damping with roughly 1.5dB - 2dB peaking at the c. 85Hz Fb and an F3 of c. 65Hz, give or take. In 225 litres, again depending on damping Qtc drops to about 0.86, Fb c. 65Hz with about 0.75dB peaking and an F3 around 57Hz.
4. Depends on the details; these are in relative terms acoustically small volumes for the drivers; to a point (a point beyond what most people here will probably want to go!) bigger is better, so it's a case of the larger you can go, the better the performance. If you stretch one dimension significantly relative to the others you'll get a longitudinal 1/2 wave eigenmode (standing wave), so you may need to add some extra damping at the base to prevent it modulating the driver.
1. Fair enough. Remember though that those 'huge' (these things being relative) sealed 1950s - '60s era sealed boxes were often on the order of about 18ft^3, or 500 litres [nearly] if you prefer metric, like some wild modern enthusiast.
2. No idea, but in that volume it may have some compression issues / sound a mite 'choked' unless you can bleed off some pressure.
3. Assuming Butterworth for the purposes of a direct comparative baseline, about 19x larger actually, although you can get ~'near enough' with about 3.5x larger. It's the last few percentage points that take the greatest increases. F3 is largely a meaningless figure in practical use, F6 and to a point F10 are more valuable. However, in 100 litres, you'd have a Qtc of just over 1.0 depending on damping with roughly 1.5dB - 2dB peaking at the c. 85Hz Fb and an F3 of c. 65Hz, give or take. In 225 litres, again depending on damping Qtc drops to about 0.86, Fb c. 65Hz with about 0.75dB peaking and an F3 around 57Hz.
4. Depends on the details; these are in relative terms acoustically small volumes for the drivers; to a point (a point beyond what most people here will probably want to go!) bigger is better, so it's a case of the larger you can go, the better the performance. If you stretch one dimension significantly relative to the others you'll get a longitudinal 1/2 wave eigenmode (standing wave), so you may need to add some extra damping at the base to prevent it modulating the driver.
Thank you so much!
So if I don't want to go crazy with size and want to achieve Butterworth qtc 0.707 then 12 incher would be better, since size would remain relatively sensible - 152 litres? I used speaker box lite app for this calculation.
PS! Scott I've seen your drawing of vented 12-250TC enclosure. Besides lower bass extension how different would it sound to 152 litre sealed one?
So if I don't want to go crazy with size and want to achieve Butterworth qtc 0.707 then 12 incher would be better, since size would remain relatively sensible - 152 litres? I used speaker box lite app for this calculation.
PS! Scott I've seen your drawing of vented 12-250TC enclosure. Besides lower bass extension how different would it sound to 152 litre sealed one?
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I make it about 500 litres sans any damping, which should drop to about 350 with reasonable lagging on the walls. c.150 litres should be around the 0.75 Qtc region once lagged. It's not critical; people obsess over Butterworth simply because it offers the lowest F3, but a few percentage points either way are likely to be swamped out by the room.
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IMHO it's not just the box size, as the treble response of the two drivers look different on paper and the 15" must just be less ragged - hard to tell with hearing them. For me, it's the treble response / presence region that will determine my long-term listening pleasure rather than bass extension.
Depends precisely how they're damped out; assuming regular lagging for the sealed and the target quantities for my damped vent reflex, then the latter has roughly 2dB - 4dB more output between Fb - 80Hz, although as you would expect < 30Hz the sealed has more; the damped vent design controls the driver better than a regular vented however, so excursion in the LF isn't much higher. Ultimately it will unload in the infrasonic region, so the sealed will provide greater protection on material that reaches down that low.
These 2 Fanes have a high Q. They are best suited to be mounted in the wall with another room as the enclosure, an OB, or in the largest aperiodic box you can live with. Not sealed, not vented, not a TL or a horn. Unles syou like a big bump up at the bottom.
The 12 can get a reasonabe box Q, the higher Q of the 15 means a much larger box.
dave
The 12 can get a reasonabe box Q, the higher Q of the 15 means a much larger box.
dave
In wall should be nice. I toyed at 40 liters in a light braced box with series cap as 3rd order mono boombox.
40 vs 9999 liter seaked box https://i.imgur.com/ovRYRpq.png
Aperiodic type might be a good compromise.
40 vs 9999 liter seaked box https://i.imgur.com/ovRYRpq.png
Aperiodic type might be a good compromise.
Nothing wrong with a sealed cab if you have a small listening room. My 12 inch Fanes sound fine in my 12x13ft room.
I designed them at 80L to make use of the 3dB hump at around 100Hz caused by the sealed load and use the rear wall boost below that, in order to give boom free bass in a restricted, and near-field environment.
Fender Tweed grille cloth pulls the top end down nicely, to give a balanced sound.
In a bigger room, more typical of those found on the American continent, I would go aperiodic with the biggest cab you can get away with as David says above.
What you do with this driver is heavily dependent on the room you are going to put it in.
Unless you go big, aperiodic in a large room, the things will loosen your fillings at the top end, in the far field if their is no Aperiodic bass support to balance out the response and they are not toed in to cross in front of the listener. I’ve heard my “small” sealed cab Fanes in such a large room situation and it is not pleasant as Scott will attest to. So my own conclusions after hearing these cabs in several different sized rooms, over the 14 months I’ve had them is:
sealed cab in small room, superb well balanced sound; in large room? My ears man, my ears, back-offa me man, it’s too piercing!
I designed them at 80L to make use of the 3dB hump at around 100Hz caused by the sealed load and use the rear wall boost below that, in order to give boom free bass in a restricted, and near-field environment.
Fender Tweed grille cloth pulls the top end down nicely, to give a balanced sound.
In a bigger room, more typical of those found on the American continent, I would go aperiodic with the biggest cab you can get away with as David says above.
What you do with this driver is heavily dependent on the room you are going to put it in.
Unless you go big, aperiodic in a large room, the things will loosen your fillings at the top end, in the far field if their is no Aperiodic bass support to balance out the response and they are not toed in to cross in front of the listener. I’ve heard my “small” sealed cab Fanes in such a large room situation and it is not pleasant as Scott will attest to. So my own conclusions after hearing these cabs in several different sized rooms, over the 14 months I’ve had them is:
sealed cab in small room, superb well balanced sound; in large room? My ears man, my ears, back-offa me man, it’s too piercing!
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Some sims. Steve’s 80 litre box, and note that going from the 350ish litre box to 1,000 litres makes little difference (less than adding (necessary) damping. 250 litre with damping seems a good compromise.
Aperiodic works by taking the hump of the smaller boxes down, and damps down the LF impedance peak.
The 15 needs a much, much bigger box.
dave
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I have been looking at the 12" Fanes for a couple of months now. The previous work Cresswell looks like it worked pretty well for his situation. There was another long thread that ened up with a 100L cab and a cardboard filter on the front to breakup the high end. Mr. Cresswell there used a tweed it looks like to the same effect.
Using the formula on chart from the previous thread:
It looks like to hit 250L you would need about 40" x 25" x 15.6". That's pretty big but not ridiculous. I;m only working on my first set of kit speakers, so please ignore me if that didn't make sense. I'd like to build a pair based on 12" Fane next.
Using the formula on chart from the previous thread:
It looks like to hit 250L you would need about 40" x 25" x 15.6". That's pretty big but not ridiculous. I;m only working on my first set of kit speakers, so please ignore me if that didn't make sense. I'd like to build a pair based on 12" Fane next.
Another option for both these drivers could be like a quasi OB. The cab volume wouldn't need to be so big as you could build an open bottom cabinet or open back etc. Both these drivers have a higher QTS than the specs claim. I was thinking of doing a cabinet to bring the driver to ear height with included legs and then just leave the bottom of the cabinet off, the legs will keep it up off the floor, then stuff the cab till it sounds the best for your/my room. Easy peasy 
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OK, I pulled the trigger on the plywood. Got some nice thick baltic birch ply pieces from my local supplier outlet. All together 31 euros!
Front and rear walls are 28mm birch ply, the rest is 24mm. I will add a brace in the middle like Steve Cresswell did. Measurements of the box will be: height 810 mm, width 400 mm and depth 430 mm. It will be around 100 litres.
Front and rear walls are 28mm birch ply, the rest is 24mm. I will add a brace in the middle like Steve Cresswell did. Measurements of the box will be: height 810 mm, width 400 mm and depth 430 mm. It will be around 100 litres.
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Another option for both these drivers could be like a quasi OB. The cab volume wouldn't need to be so big as you could build an open bottom cabinet or open back etc. Both these drivers have a higher QTS than the specs claim. I was thinking of doing a cabinet to bring the driver to ear height with included legs and then just leave the bottom of the cabinet off, the legs will keep it up off the floor, then stuff the cab till it sounds the best for your/my room. Easy peasy
this is worth trying, it s what I had in mind when I built my 15” speaker
A Big'un - the Audio Nirvana Super 15
There’s a related design called the Boffle, you can Google that.
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