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Discussion Starter · #1 ·
It's been while since I posted, but I have done a few projects in the past. But I need help with a new project.


My latest goal is to make a Sub that will be used 100% for music. It will be 100% outdoors, used to add 30-35hz bass to powered DJ speakers. Sound quality is not the primary goal, simply adding bass to give the music some presence. It should put out a lot of bass at that small range.


Two of the box dimensions must be 14.75" tall x 16-17" deep. Width can be up to 36". Vent must be on top of speaker (on the 16"x36" top)


I have a 200w plate amp. I need an inexpensive driver (less than $100) that can be cranked up without failing.


Any thoughts??
 

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Look for pro audio high sensitivty woofers. Im not sure whats available for under $100 though.
 

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Discussion Starter · #3 ·
Thanks Penn, I have a pro woofer already. It is an Eminance Delta 12LFA.


I need some help designing a box. I am thinking bandpass would work great for this since it rolls off so steeply around 30Hz, but I have no experience designing one and need some help.


Ideas?
 

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Discussion Starter · #4 ·
Alright, I know that there are people on this forum that know how to build a band pass woofer, you guys know everything. So let me ask this another way.


How big (volume) should the box be for a band pass sub that rolls off around 35-40Hz? I need to figure out how big the back chamber should be, how big the front chamber should be, and how big the slot port should be.


I will be using an existing Eminance Delta 12LFA and Dayton 200w plate amp.


*Power handling: 500 watts RMS

*VCdia: 2.5" *Le: 1.45 mH

*Impedance: 8 ohms

*Re: 6.06 ohms

*Frequency range: 44-3,000 Hz

*Magnet weight: 56 oz.

*Fs: 51 Hz

*SPL: 94.6 dB 1W/1m

*Vas: 2.4 cu. ft.

*Qms: 7.28

*Qes: 0.51

*Qts: 0.47

*Xmax: 4.8 mm

*Dimensions: Overall Diameter: 12.03", Cutout Diameter: 10.95", Mounting Depth: 5.35".


I really need some help figuring this out.


Thanks
 

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Download WinISD pro alpha version.


Select Eminence Delta 12LF driver (is it the same driver?), select 4th order bandpass or 6th order bandpass then you can change the box size and tuning to see the plots.


btw, what bandpass frequency do you want ?
 

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Discussion Starter · #6 ·
Ok, thanks again.


I'm messing with this. But I have some questions.....


The speakers this will compliment have a frequency response of 50hz-20Khz. Where should I tune this 4th order sub? Should it be at 40hz, 45hz, 50hz? I'm not sure where I should be aiming.


What should the ideal plot for this type of sub look like and how high should it reach?? Above the 0 line?


Thanks
 

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If the speakers are rated to 50Hz then you should still cross them over up around 80Hz to get the best crossover slope.


I would say you do not need to build a band pass sub at all just a ported one but I have to know what your are using for a processor? Do you have crossovers abilities?


btw, you asked for experts, they haven't posted yet but you have me
 

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Just be carefull in the case of sound reinforcement and the HP filter of the plate amp. If the tune is too high there won't be anything to save the driver from exceeding xmax or god forbid xlim.
 

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Quote:
Originally Posted by Jay1 /forum/post/16978925


That driver's not much for a sub, but it actually models really well in a 6th order band pass. A 3.5 ft3 rear chamber with with a 4" round by 5.5" long port, and a 1 ft3 front chamber with a 4" round by 1.5" long port is what I recommend.

Looks fine but why make it a complex build?


A 5 cuft ported box (6" round port 14" long) is tuned around 34Hz and if he has a crossover at 80Hz for his mains it will be just fine, no?


Can we even tune that driver down to 34Hz?
 

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Don't do much work with bandpass but i thought i'd plug my NHT 10" drivers in and see what comes out in Unibox and i'm quite surprised how well they did given your application. Here's a graph with 200w input power per pair of 10" woofers per box.

Attachment 149841


No worries with xmax in this case. I have four of these 2 new and 2 slightly used if you want em for $100 plus shipping. The model is only two, adding a second box with two more increases output to almost 120db....in other words LOUD!.
 

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Quote:
Originally Posted by mayhem13 /forum/post/16978998


Don't do much work with bandpass but i thought i'd plug my NHT 10" drivers in and see what comes out in Unibox and i'm quite surprised how well they did given your application. Here's a graph with 200w input power per pair of 10" woofers per box.

Attachment 149841


No worries with xmax in this case. I have four of these 2 new and 2 slightly used if you want em for $100 plus shipping. The model is only two, adding a second box with two more increases output to almost 120db....in other words LOUD!.

Thats pretty cool, I have 4 of those in my garage still with the 100W plate amps....maybe I need to build some end tables for fun.
 

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Discussion Starter · #13 ·
Guys, what I am trying to do is add some bass to some existing powered DJ speakers I have. These are used only for music while I am tailgating at football games. The DJ speakers are built into a trailer so I need a sub that sends all of its energy out a port so it can also be built into the trailer (see below). A standard ported sub will not work because I cannot have the driver exposed (I have no room), only the port or ports. The actual driver will be inside the box, inside the trailer.


The existing DJ speakers sound OK, but they don't have any bass punch, so I am trying to add some by using a driver and amp I currently have. I am also doing this because I want a small project to do.


Here is the trailer and as you can see, I can cut some ports out, but no room for even a 12" driver to be exposed. There is a built in speaker on each side of the TV, the components are under the speaker on the right, and a smaller LCD below the speaker on the left. I can cut the ports right under the large LCD in the center.

 

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Quote:
Originally Posted by penngray /forum/post/16978952


Looks fine but why make it a complex build?


A 5 cuft ported box (6" round port 14" long) is tuned around 34Hz and if he has a crossover at 80Hz for his mains it will be just fine, no?


Can we even tune that driver down to 34Hz?

That band pass box is tuned to 34hz as well, it has more output from 100-40hz (average of 2db more, has no roll off till 50hz), with the ported box gaining the edge to 30hz. Cone excursion is practically identical for both alignments with both reaching xmax at 60W, good thing Xlim is high, takes 450W to bottom the driver
 

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Cool! Jay has you covered
 

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Discussion Starter · #16 ·
So Jay, you are recomending the 6th order box? That means that both chambers are ported correct? Doesn't matter the shape of the box right? Also, the ports can bend using an elbow correct? Thanks
 

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Quote:
Originally Posted by Video /forum/post/16979079


So Jay, you are recomending the 6th order box? That means that both chambers are ported correct? Doesn't matter the shape of the box right? Also, the ports can bend using an elbow correct? Thanks

yes, yes, no, the ports are very short so no elbow is needed. You will need to make the box slightly larger then your listed dimensions for the 4.5 ft3 (3.5 ft3 rear, 1 ft3 front) required.
 

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Discussion Starter · #20 ·
yes, using WinISD to model. Have box set to 3.5 cu ft rear chamber, tuning freq 35, 1 cu ft front chamber, tuning freq 35. Vents are one 4" per, 4.99" rear, 24.87" rear.
 
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