True, but others on the 'full range' forum have proven MJK's MathCad software accuracy numerous times and when it comes to damping, it has proven to be a bit conservative, so probably won't need as much as I inputted.
GM
Hi MMJ,
At this stage, just populated by the user. I have started looking at other possible options though.
Interesting 🙂.
Kind regards,
David
At this stage, just populated by the user. I have started looking at other possible options though.
Interesting 🙂.
Kind regards,
David
Would stuffing be useful in my simple tapped horn for above stated reasons? First of all, what stuffing would I need to buy, and secondly, could someone explain what the different stuffing sliders mean in Hornresponse (Speaker Wizard). They seem quite cryptic but I'm sure it is pretty simple, please ELI5.
HEY NOW ,
Being that this is post #666, we should celebrate and enjoy this special moment with some complimentary Slayer
Slayer - Seasons In The Abyss - YouTube
Being that this is post #666, we should celebrate and enjoy this special moment with some complimentary Slayer Slayer - Seasons In The Abyss - YouTube
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Saba,
I imagine it might! I would only add it to the very beginning of the path (near the closed end of the "pipe") .. Probably no more than the first 25% of your path , especially since you are using an expansion .... It seems that it is generally considered more advantageous to use filling/stuffing in tapped pipes without too much expansion (like yours), no expansion at all or reverse taper .....
Tapped Horns with very small area near the throat (like TH cabs with high expansion rates and high compression ratios) can lose too much SPL with the addition of anything more than just a small amount of stuffing ....
In HR's Wizard you have handy sliders for the density of stuffing/filling and you also have sliders to adjust where the filling is placed within the horn or pipe segment ...
People commonly use Fiberglass insulation material, Poly fiberfil (pillow batting) , or Wool .... I have even made damping pillows composed of light dryer lint encased in Poly Fiberfil sheets for a recent fun & low-cost project ... I usually apply some spray adhesive and some staples to permanently fix the filling in place when i have decided how much i want to use and where i want it ..
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Sure! Be careful though, it's very easy to roll off the bass too much. Don't know what DSL uses, but it seems to have just the right amount of damping: http://i264.photobucket.com/albums/ii175/brandonnash/DSCF3499.jpg
Anyway, look through the pictures for more placement info and compare it to what works best overall in HR as strictly a guide since it's a different type of TH alignment.
GM
Seeing as how I have no idea on what kind of dampning that is I'll probably just skip it.. Question: WHERE DO YOU BUY WOOD THAT BEAUTIFUL, ok lol they obviously buy it by the truck but holy <expletive> that's the nicest baltic birch I've laid eyes on. Would kill to have a CNC right about now after cutting out 4 handles via router (and template).
Trimmed up the 48.5 inch pieces to 47.875 to match the other wood I have today, + all but the one handle near the drivers. Tomorrow is likely corner brace cutting and first glue up day (usually I cut corner and normal braces to fit as things never come out "perfect" -- see lack of CNC comment.
OK, thanks; my monitor is 1080P, but my 2k computer is apparently unable to give me anywhere near enough resolution to view it as more than a thick, solid vanilla colored paper towel.
GM
GM
Search for open cell foam in sheet or roll form and probably a 1/2" thick.
Doesn't look any nicer than what I can order at the local Lowe's. Note that it's probably 13 ply same as I've seen on earlier DSL cabs [and TD recommends] vs the normal 11 or less, so this may make a difference.
GM
There isn't a lowes near here (at school) but the wood I can get from the Lowes back home is crap, no one sells even ply plywood, except for the 1 hardware store (home) which sells 5x5's of BB. Best I can get back at school is 3/4 inch Arauco which goes for 40 a sheet. If they sold arauco in half inch that is what I would end up getting, for now I have to deal with heavy 3/4. They really need a decent lumber yard in San Luis Obispo County.
The Hornresp sims I've tried show not much difference if the damping is inserted between S1 and S2, but as soon as you hit S3 and S4 you can significantly alter the TH's response (in a bad way) if you put in anything more than a little damping. This is actually in line with some other information I read about the use of absorption materials, where its said to be less effective at a high pressure / low velocity point (e.g. at the throat) than at a low pressure / high velocity point (e.g. the mouth).
There is an interesting possibility that I haven't tried yet though - trying to damp out the resonance in the TH that causes the dip in response just above the passband (and the jaggies above). It might be possible to do that with a 3~4" thick wedge of damping material placed strategically within the horn, thick enough to be effective down to the TH's passband.
There is an interesting possibility that I haven't tried yet though - trying to damp out the resonance in the TH that causes the dip in response just above the passband (and the jaggies above). It might be possible to do that with a 3~4" thick wedge of damping material placed strategically within the horn, thick enough to be effective down to the TH's passband.
Brian , i wonder if a thicker version of this could work:
Sonic Barrier 1-1/4" 3-Layer Acoustic Sound Damping Material with PSA 18 x 24"
or this kind which is thicker :
Acoustic Sound Damping Eggcrate Foam California Prop 65 Compliant UL 94 2-1/2" x 12" x 12" Two Pieces
Guys for anyone who was wondering: This (correcting my earlier statement due that my previous creation was the best I'd seen) is the most ridiculous SPL per T60 sized cab (I.E. 20 cu. ft external) I've seen. It's me scaling up my 49.5 inch TH to a 60 inch double double loaded (twice as wide as my single load) cabinet. 4 drivers, 4000 watts, SWR drivers 90 volts and still within XMAX. We're talking 132-135 dB in one cabinet down to 30 Hz guys. Anyone else impressed? Of course now we are talking dedicated amp circuits and 4kw but it is still more efficient - and goes lower than than 2 of my 2x12 horns stuck together and roughly the size of said 2 cabinets.
Let me know if the slightly higher compression ratio would be an issue. the expected mount pattern would be two by two (deep and tall). Definately needs baffle rings but that's besides the point -> this is one sub you only need one of.
Okay enough blabbering: see below
Oh and P.S. the reason that MMJ's standard of "doubling the inductance" from the stated value is valid is because the standard is to report it as 1khz or 20 khz inductance, which as we know a drivers inductance is very frequency dependant and almost all have ~1.5-2x the inductance in the subwoofer passband -- i.e. <100 Hz, than at the spec'ed frequency, of course the only way to get it right is an inductance curve - not too hard to measure if you have the tools.
Let me know if the slightly higher compression ratio would be an issue. the expected mount pattern would be two by two (deep and tall). Definately needs baffle rings but that's besides the point -> this is one sub you only need one of.
Okay enough blabbering: see below
Oh and P.S. the reason that MMJ's standard of "doubling the inductance" from the stated value is valid is because the standard is to report it as 1khz or 20 khz inductance, which as we know a drivers inductance is very frequency dependant and almost all have ~1.5-2x the inductance in the subwoofer passband -- i.e. <100 Hz, than at the spec'ed frequency, of course the only way to get it right is an inductance curve - not too hard to measure if you have the tools.
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That's 4 SWR 12d4 drivers. 20 mm Xmax 1000 watts a piece.Box twice the size as the 2 driver SWS box.
I'll check on what 4 SWS look like in a similar size.
SWS is more efficient and better 38-75 on a watt basis, cheaper too. Just doesn't take as much power and has a slightly weaker cone. I'd still go with the SWS. 100-150$ driver savings per box (4 drivers) with same or better spl per watt.
SWR looks darn good in a 17 Hz tapped horn though (obviously, seeing as it has the lower fs)
See below, note corner-loaded, 2 drivers, 70 v displacement limited (SWR) in a 483 L or roughly 20 Cu ft EXT or 17 Cu ft int box.
Think lil-wrecker response wise, add 4 dB, subtract 200 L of cabinet >.< substitute 2 12's for the 15 substitute roughly 1200 watts for the 5-600 they were using.
SWR looks darn good in a 17 Hz tapped horn though (obviously, seeing as it has the lower fs)
See below, note corner-loaded, 2 drivers, 70 v displacement limited (SWR) in a 483 L or roughly 20 Cu ft EXT or 17 Cu ft int box.
Think lil-wrecker response wise, add 4 dB, subtract 200 L of cabinet >.< substitute 2 12's for the 15 substitute roughly 1200 watts for the 5-600 they were using.
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