Hey guys, just posting a picture of my "budget" 18" BR I built for a buddy. putting the finishing touches on it... really stretching my overly slim budget to the limits (no corner hardware etc). 3/4 aracuo and 1/2 birch for the port.
Its tuned to 37hz with flared ports (Port speed stays below 15 m/s at xmax). excited to hear it!
Its tuned to 37hz with flared ports (Port speed stays below 15 m/s at xmax). excited to hear it!
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nice
I'm curious how the flared on both sides short port works for tuning frequency. The Danley 12" box has something very similar, with less of a "straight" port in between. Looks like you did a huge favor for a buddy, doesn't seem like you got much $ for building it by the way you describe it 
Looks good thou!!
Looks good thou!!
I got less than $10 an hour.....
To be fair, a little backstory.
he asked me about building a sub about a year ago initially (he is the manager of a small bar that unintentionally became a busy hipster dance club). We discussed pricing, I went out of town on holiday, and when I returned, I found a used jbl prx518s at the club. they had picked it up for $300 from a resturant that had recently closed (same resturant was selling 4 dbx pa + for $50 a piece and I MISSED THEM!)
I tell them they made a poor decision.... walk away, 2 months later, I get a call. they blew it up. I come in, diagnose the speaker as blown coil. point them in the right direction of the proper recone kit, and recone it for $40 labor. 2 months later, the amp dies... after a couple months of no sub, they finally come to me with a $800 budget (including Amp, which we got used, AND a DBX PX because their current "processing" is a rack full of 20 year old garbage that has no sub hipass capabilities, or balanced patch cables in sight).
So... here we are.
I modelled the port in hornresp. If I had kept the port a constant width, then I would have had to make it far longer. "bottlenecking" it, allows the length to come down a tad, but still offers you a significant port velocity reduction at the mouth and throat of the port. I wanted to stay a good distance away from the back wall as to not affect tuning.
Thanks for the encouragement guys!!!
To be fair, a little backstory.
he asked me about building a sub about a year ago initially (he is the manager of a small bar that unintentionally became a busy hipster dance club). We discussed pricing, I went out of town on holiday, and when I returned, I found a used jbl prx518s at the club. they had picked it up for $300 from a resturant that had recently closed (same resturant was selling 4 dbx pa + for $50 a piece and I MISSED THEM!)
I tell them they made a poor decision.... walk away, 2 months later, I get a call. they blew it up. I come in, diagnose the speaker as blown coil. point them in the right direction of the proper recone kit, and recone it for $40 labor. 2 months later, the amp dies... after a couple months of no sub, they finally come to me with a $800 budget (including Amp, which we got used, AND a DBX PX because their current "processing" is a rack full of 20 year old garbage that has no sub hipass capabilities, or balanced patch cables in sight).
So... here we are.
I modelled the port in hornresp. If I had kept the port a constant width, then I would have had to make it far longer. "bottlenecking" it, allows the length to come down a tad, but still offers you a significant port velocity reduction at the mouth and throat of the port. I wanted to stay a good distance away from the back wall as to not affect tuning.
Thanks for the encouragement guys!!!
Sure i'll post it later when im back home. Soaking some music vibes all today as there is a local festival in town this week (hopscotch musicfest)
Trust me... I'll be vicous with my driverack settings. I could have gone with te dayton 465 but i wanted to make sure it was bulletproof so i sprang for the more expensive driver.
Trust me... I'll be vicous with my driverack settings. I could have gone with te dayton 465 but i wanted to make sure it was bulletproof so i sprang for the more expensive driver.
Heres the sim results. just around xmax is shown at 85v input. I'll likely peak limit around 90... they are using some old qsc bridged into 8 ohms.
EDIT
i've also attached horn mouth velocity at 85v. Keep in mind the horn velocity is shown WITHOUT the hipass, thus the reduction in voltage at the peak will easily keep it within the 15 m/s threshold (barely).
I might also add that although I've shown the graph in 2pi, its permanent home will be wall loaded (driver facing a solid brick wall)
EDIT
i've also attached horn mouth velocity at 85v. Keep in mind the horn velocity is shown WITHOUT the hipass, thus the reduction in voltage at the peak will easily keep it within the 15 m/s threshold (barely).
I might also add that although I've shown the graph in 2pi, its permanent home will be wall loaded (driver facing a solid brick wall)
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I like your design here, Sine143. I have been following this subwoofer forum and and playing with Hornresp for a while, trying to come up with some decent designs for a pair of 18" Peavy LowRiders I have here.
I have learned how to use Hornresp pretty well, but I can't find any directions on how you modeled the tapered port. I can see from your schematic you posted how it is supposed to look, but I can't figure out how you did that. Would you please take the time to explain this to me?
retail?
Driver (faital pro 1030hp 18): $415
Wood (aracuo 3/4, 1 sheet, plus scrap BB) $35
Glue (PL premium, 2 tubes): $10
Durham Rock hard putty (1 tin): $3
sandpaper: $5
Speakon jacks: $10
Grille Material (comes in pair, will list price for 1): $50
Duratex (used 1/4 a gallon, but I'll include the total cost of the gallon): $80
Assorted Screws/washers: $15
Total cost *RETAIL*
$623
shave a solid 175 off that price for how much it cosot me.
Driver (faital pro 1030hp 18): $415
Wood (aracuo 3/4, 1 sheet, plus scrap BB) $35
Glue (PL premium, 2 tubes): $10
Durham Rock hard putty (1 tin): $3
sandpaper: $5
Speakon jacks: $10
Grille Material (comes in pair, will list price for 1): $50
Duratex (used 1/4 a gallon, but I'll include the total cost of the gallon): $80
Assorted Screws/washers: $15
Total cost *RETAIL*
$623
shave a solid 175 off that price for how much it cosot me.
Sorry to double post, but I cant add it to the previous one because edit is disabled after x amount of time
Dropped it off at its new home. unboxed their driverack PX and went about setting it up. I am VERY pleased with my initial impression. SOLID output, and I was maybe looking at 10mm excursion p2p during testing. good extension into the mid 30s as well. I would put this cab up against 2, possibly 3 single 18 budget cabs (peavey, yamaha, jbl etc) ANY day.
Dropped it off at its new home. unboxed their driverack PX and went about setting it up. I am VERY pleased with my initial impression. SOLID output, and I was maybe looking at 10mm excursion p2p during testing. good extension into the mid 30s as well. I would put this cab up against 2, possibly 3 single 18 budget cabs (peavey, yamaha, jbl etc) ANY day.
the budget cabs generally sport drivers with weak motors, and 6-9mm xmax. they do make up for it with light cones, but as far as output below 50hz goes, this cab has it by almost 10db in output capabilities.
Oh, AND they all use way to small ports with airspeeds of over 50 m/s lol
Heres my rough sim of the box they bought over christmas (JBL powered single 18, 1 ohm driver). decent output above 60 for a cab that is a hair smaller than mine (maybe 1 cubic foot max), but again, a total slouch below that.
EDIT
Jimmy 420, refer to this little gem of the internet, Hornresp for dum....erm everyone
http://www.hometheatershack.com/for...32-hornresp-dumb-hmm-everyone.html#post324331
By using the alternate method for vented enclosures (not the simple one where you just plug in Ap and Lp) you can form complex horn shapes with as many segments as you please (hornresp segment cap permitting).
Oh, AND they all use way to small ports with airspeeds of over 50 m/s lol
Heres my rough sim of the box they bought over christmas (JBL powered single 18, 1 ohm driver). decent output above 60 for a cab that is a hair smaller than mine (maybe 1 cubic foot max), but again, a total slouch below that.
EDIT
Jimmy 420, refer to this little gem of the internet, Hornresp for dum....erm everyone
http://www.hometheatershack.com/for...32-hornresp-dumb-hmm-everyone.html#post324331
By using the alternate method for vented enclosures (not the simple one where you just plug in Ap and Lp) you can form complex horn shapes with as many segments as you please (hornresp segment cap permitting).
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