Yes Crafty`s sub are very nice and I am sure they do perform great! I dont know the Amp, but it looks like it could drive them!
Sadly BMS finished the 860 types cause they were a bit better whenit comes to real low stuff. But the 862 is one of the best 18" Drivers I do know and still my fav!
Sadly BMS finished the 860 types cause they were a bit better whenit comes to real low stuff. But the 862 is one of the best 18" Drivers I do know and still my fav!
You're welcome!
OK, curious how low since with relatively minor stuffing the ~212.5 L is only ~17 ms/12 Hz.
FWIW, back on the long gone bass list this was a hotly debated subject for awhile, so simmed a few of my low tuned 'classic' reflex, [ML]TL, EBS alignments and the latter was worst case by far at up to ~35 ms/20 Hz with ~20 Hz Fs woofers corner loaded, they all were considered to be 'heart attack fast', so while I don't recall if there was a consensus, I concluded my types of vented alignments were plenty good enough even if starting to rise around ~342 Hz where our hearing acuity starts rolling off.
OK, curious how low since with relatively minor stuffing the ~212.5 L is only ~17 ms/12 Hz.
FWIW, back on the long gone bass list this was a hotly debated subject for awhile, so simmed a few of my low tuned 'classic' reflex, [ML]TL, EBS alignments and the latter was worst case by far at up to ~35 ms/20 Hz with ~20 Hz Fs woofers corner loaded, they all were considered to be 'heart attack fast', so while I don't recall if there was a consensus, I concluded my types of vented alignments were plenty good enough even if starting to rise around ~342 Hz where our hearing acuity starts rolling off.
Is the taper widest at the ends and narrowing at the middle or the other way 'round?
I first saw something about this HERE (He refers to laminar vent and laminar air flow so with the word laminar Google nets PMC talking about their "Laminair" thingy).
. . . . and lots of mentions online but I haven't found any straightforward explanation of how to design it. Can you say or point to something ?
Thanks
Hi,
The more conventional description is "Flared" rather than "Tapered", but the picture that Art posted shows the concept perfectly well - the outer ends of the port expand outwards to reduce turbulence caused by the abrupt change in flow from inside the port to outside it.
There is a small program called "Flare It" that allows some design calculations to be done.
Thanks GM and David.
I was thinking to use standard flared tubes in a ported Sub (approx. 30-80Hz) when I happened to see the French page with the laminated port appearing to be shaped like two gently flared conical cylinders joined at their apex so there is no straight wall section. Wakup2's description made it sound like it was superior to the standard flared port in some fundamental way. However, what I gather from reading GM's linked thread and looking at David's linked "Flare It" is that the difference is appreciable only at high outputs and would not make any audible difference at living room (non-HT) listening levels .
Have I got it right or is it worth investigating further for low-medium level sound?
Thanks
I was thinking to use standard flared tubes in a ported Sub (approx. 30-80Hz) when I happened to see the French page with the laminated port appearing to be shaped like two gently flared conical cylinders joined at their apex so there is no straight wall section. Wakup2's description made it sound like it was superior to the standard flared port in some fundamental way. However, what I gather from reading GM's linked thread and looking at David's linked "Flare It" is that the difference is appreciable only at high outputs and would not make any audible difference at living room (non-HT) listening levels .
Have I got it right or is it worth investigating further for low-medium level sound?
Thanks
Depends on the driver's low distortion peak power capability (Xma)], which is often way < its electrical power rating(S) at really low tunings, so what do the sims 'say' for < ~ 17 m/s vent mach? Or if louder peaks than you want/need/afford, find the max lower Xmax and design based on it.
In general, if it dictates a vent longer than ~2/3 cab depth or the pipe diameter (ROT) [or more technically correct its length + end correction] where it is, then you have to decide which way you want to go and historically the vent was just damped to 'taste', usually by the grill cloth.
In general, if it dictates a vent longer than ~2/3 cab depth or the pipe diameter (ROT) [or more technically correct its length + end correction] where it is, then you have to decide which way you want to go and historically the vent was just damped to 'taste', usually by the grill cloth.
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Thanks again. Playing with the Flare It (and Boxnotes) programs set for your spec'd 17 m/s and a stock 4" flared port looks to be ok no matter what else I do. I still have to decide on a driver at which point it all gets revisited of course but this is helping me to get oriented and your help is really appreciated.
I'm still a bit miffed by the use of thestrikethrough in your post. Did you intend that?
I'm still a bit miffed by the use of the
By miffed I meant I would have wondered about the purpose of the strikethrough if it had been what you intended. It began at a place that might have made sense with brackets and I wondered if that's what you had tried to do.
This all goes back to the earlier thread on strikethrough and Epanorthosis.
Anyway, it's all beside the point. I just wanted to say thanks. It's easy to get overloaded by the huge amount of detail one can get into when thinking about design of the whole speaker system - without years of real experience it's way beyond my capacity to keep it all in mind - and I've been eager to get some of the apparent complexity down to simpler underlying principles. It's taking a while for it to stick but you're helping me to do that and it's appreciated.
This all goes back to the earlier thread on strikethrough and Epanorthosis.
Anyway, it's all beside the point. I just wanted to say thanks. It's easy to get overloaded by the huge amount of detail one can get into when thinking about design of the whole speaker system - without years of real experience it's way beyond my capacity to keep it all in mind - and I've been eager to get some of the apparent complexity down to simpler underlying principles. It's taking a while for it to stick but you're helping me to do that and it's appreciated.
Interesting! I've been getting away with using the brackets after the initial discussions, so thought the 'powers that be' had made it so, but guess I had one too many in the same paragraph 'trigger' it.
Yeah, like they say, 'Rome wasn't built in a day' and FWIW I've been ~involved in this hobby/business in one way or another for nearly 66 yrs and still learning, though in my defense there wasn't much available to learn from way back when unless one had the necessary education, higher math aptitude required to solve/manipulate complex equations, so folks on the forums today are getting at least a decade head start.
Yeah, like they say, 'Rome wasn't built in a day' and FWIW I've been ~involved in this hobby/business in one way or another for nearly 66 yrs and still learning, though in my defense there wasn't much available to learn from way back when unless one had the necessary education, higher math aptitude required to solve/manipulate complex equations, so folks on the forums today are getting at least a decade head start.
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Well yeah, re the internet and all; I was referring to actual theory/design knowledge, i.e. I learned little the 1st decade, then the vast majority in the next decade and just mostly new tech as the patents came out for ~ the next three decades when I got on-line, hence the 'at least a decade'; though in retrospect, my intense decade could be all done in the time span of learning the physics, etc., during just the time spent in college courses.