I plan to extend the low end of my current system with a subwoofer covering the band of 20 - 60 Hz or better, 20 - 80 Hz. The band above would be covered by a LaScala sized (mid)bass horn or a Paraflex C2D. I have a pair of RCF LF15X401 drivers that could be used in this application. This sub will be placed in a corner, the largest dimension cannot exceed 2 m.
So what are my options...I started simulating a long pipe that would work (with EQ of course). That gives me 180 l volume and a quite good form factor to place it upright in a corner:
This pipe was inspired by bentoronto and this 17ft sub. This one is slightly shorter.
And then I thought - how about the plain old bass reflex tuned to 20 Hz in the same volume box (including the vent):
A third option would be a ML-TL, but I do not feel skilled enough to design one. A sealed box of the same size would loose too much efficiency if I understand things correctly. A tapped horn would most probably not fit the 180 l limit?
My output will be limited by the excursion of the woofer anyway, so is there any point why to build a pipe/TL as a sub instead of a plain old BR? I actually see a point in bracing - a dual fold in bentoronto's style should result in a quite sturdy box with minimal effort. Also the form factor is appealing since it would allow for some easy placement in my room. On the other hand, the bass reflex box could be built in the same form factor - with the speaker close to the floor and the vent close to the ceiling.
Any thoughts on this? My idea would be to build one sub in this large size and use the other driver in a smaller box to fill in for room problems.
So what are my options...I started simulating a long pipe that would work (with EQ of course). That gives me 180 l volume and a quite good form factor to place it upright in a corner:
This pipe was inspired by bentoronto and this 17ft sub. This one is slightly shorter.
And then I thought - how about the plain old bass reflex tuned to 20 Hz in the same volume box (including the vent):
A third option would be a ML-TL, but I do not feel skilled enough to design one. A sealed box of the same size would loose too much efficiency if I understand things correctly. A tapped horn would most probably not fit the 180 l limit?
My output will be limited by the excursion of the woofer anyway, so is there any point why to build a pipe/TL as a sub instead of a plain old BR? I actually see a point in bracing - a dual fold in bentoronto's style should result in a quite sturdy box with minimal effort. Also the form factor is appealing since it would allow for some easy placement in my room. On the other hand, the bass reflex box could be built in the same form factor - with the speaker close to the floor and the vent close to the ceiling.
Any thoughts on this? My idea would be to build one sub in this large size and use the other driver in a smaller box to fill in for room problems.
That looks good. Is that based on a certain Boxplan folding scheme? I think I would have a hard time transferring this record to a box layout. What is the rear chamber in a TH? I think I am a bit lost here.
It isn´t based on any bloxplan, the driver front volume is connected at the begining of the horn, and the driver rear volume is connected at one point of the horn.
Now I understand, but still cannot make this into a box (or, a prismatic box). I try maybe later with some Excel optimalizations.
Hmm, surprised BW didn't suggest the B0$3 50% solution 😉, i.e. 2:1 CR pipe (AKA Acoustic Wave Cannon). Regardless, tuning a driver to ~an octave below Fs is best done with some form of TL/horn, so you're on the right path for either standing it up in a corner or laid out along a wall/floor junction. 😉
Wave Cannon sounds good! I will try it in Hornresp. I think I could fit it into the room with a single L bend - build a small box with the 15" woofer and add removable extensions with butterfly locks. Short pipe up, long on the floor.
Well, didn't mean making a BWC per se, just use a 2:1 CR pipe, preferably tapped to make for an easy fold:
If wanting to do a BAWC, recommend the late djk's half square wave variant to get a full 1 WL loading: https://www.diyaudio.com/community/threads/acoustic-wave-canon.9501/page-13#post-1175482
The MOAK:
https://www.diyaudio.com/community/...ors-aka-the-magnificent-monster.254948/page-6
Not yet built. Only simulation in Akabak.
https://www.diyaudio.com/community/...ors-aka-the-magnificent-monster.254948/page-6
Not yet built. Only simulation in Akabak.
That one uses a 12" speaker? I would like to use what I have. A modular build based on the Cannon should be the most practical I think.
This is inspired by the Bose AWC. Quite large resulting volume, but it would consist of a speaker holder and three pipe parts with 40 x 40 cm inner cross section. Using one corner and front wall to floor (or ceiling) edge.
You can follow the Official Rules of transmission line design and get a large resonant cabinet.
What I advocate as making a great sub is just a long tube with lots of stuffing that vents far from the driver. Can have quite a dainty floor area but reach to the ceiling.
I think the trick of sticking into your system any strategically tuned element (mechanical or electrical) is a dead-end strategy of the last century as far as careful listening goes. That's why OBs, membrane drivers, and motional feedback are coming to the fore now.
We won't have great sub-woofers until drivers with sub-sonic resonance are available.
You know whats impossible, ?
To you argue that. it’s all true anyone can experience it by building exactly the whole tire rear as a stuffed and long path.
Fact that’s essentially the whole rear of Any MTM or would be upper base ormidrange speaker for me. Almost for the same exact reasons you’re letting the very bottom contribute I’m saying to hell with it I’ll get rid of it because then the front is such a easy perfect solution to sneak in in the most difficult area?
(TLDR: What a lot of silly math goofy angles and dangles all associated with 30 and 360 or pi divided by six seems to In much higher orders and confusing to perceive Outside of the basic shapes of a sphere or simple platonic solids be some kind of strange multi dimensional connection and shapes in time and frequency etc. etc. it also functions in the low frequencies associated with 30 Hz and around all of that??))
However I hate /can’t stand the compounded version of ringing with a compound version of a really bad resonance issue because it’s compounded!!😜😜😜
it is painful If it doesn’t have some high frequency material accompany it I don’t know what is causing such an inner ear issue as those things just plain suck! and if really pushing it with that combination of beat frequencies or whatever is in the main part of your music that suddenly wasn’t in the same just prior is a realIt’s as if the cones gonna fold in halfOr you’re gonna burst the gasket on the access panel or the damn thing is go back to lauch itself off the ground. I wouldn’t be surprised if somethings not gonna get damaged in the driver very quickly if not addressed because it is violent.
That’s it as horrible as it is when you find a way to fix it and how to math and that seems to lean towards an overall lack of discontinuity in the cabinet but I’d even end up being a mathematical connection to a balance and a comfort zone for everything that is 360 and not just circumference or around it but as a mathematical reference to a circle what occurs inside perfect rectangles essentially.
There’s a connection between all of that one number and the connection between 100 cm long panel pulled up 15° off-center and released exactly 1 second or traverse in ark in the swing of 05238 radian and that will be in a straight line distance of .5. And that’s pi divided by six in reference to a circle for 30°
if you take a cube length width and height of one and a sphere with a diameter put that into the cube full of water it will displace 52.38% of the volume in the same time in the equation for the volume of a sphere which shares if the radius is one of the number for the constant 43 divided by pi part is 419-0476 and that if the radius is .5 will become 05238 didn’t get that from an abbreviated form of C equals two pi R were 30° again is 5238 when 0.5/3 is pi For you substitute the radius to get the same result as before you take a cube and you put two side-by-side in the long dimension is twice the short dimension exactly when that long to mention is 5For you substitute the radius to get the same result as before you take a cube and you put two side-by-side in the long dimension is twice the short dimension exactly when that long to Point is twice 5238 and the short sides are exactly 5238 and the perimeter of that is pi at 3.142857. And the hypotenuse of it and it’s rectangular long points he squared plus B squared plus B squared equals C squared will be 1.3095338 which is 75° which is a quarter wave length function of the speed of light at 300 for half of that which is 150 or 3/4 of it which is 225 now using 300 cm pipes and Cordaway speakers or 30cm from driver to driver will have a very unique relationship to this 5238. Speed of light doesn’t care where or how are using it it’s three 33,000 3,000,300 whatever it’s a three or the circle that seem to be arguing with each other here one having an extra one seventh you can make a triangle that fits in a circle that has an exterior of pi most of the stuff is really confusing and not well understood and known because of unit conversions between the two systems the radius and diameter of the sun and pie and all of that had two sets of numbers all of which mean the same thing.
You don’t have to sequester your real waves in such a way if you can pinpoint where in particular you want to do things instead.
Again I really like the way you do that and most definitely in some other areas so I’m not without your perspective or somewhat pessimistic or derogatory towards things that I don’t like and neither do you so that maybe there’s something here to see especially if I have experienced the worst of the worst disasters in these things and then seem to have fixed it all thank God we’re all thrown the whole damn idea it might go into the dumpster fire and walked away never to return is that awful but then suddenly it isn’t?
Attachments
Last edited: