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I'm looking to build a small amplified sub that will fit in my apartment, and give some more oomph to my system. I could spend $400 and a bit on this project.


I've done some research on this, and helped my brother build a sub that's somewhat larger than what I'm looking for. Based on what I've found, a sealed enclosure will be easier to construct and model, and later on if I get more ambitious I can take the time to build a ported enclosure and move the driver and amp to it. So unless a ported enclosure really wouldn't be much more work or would have a huge benefit, sealed it is. After doing some reading on diysubwoofers.org, I came across the sealed sub calculator linked there, which has been very instructive.


Browsing through Parts Express, I found the BASH 500W amp and the Dayton RSS315HF-4, which look like a good match for my situation. Modeling the driver in the spreadsheet shows me I could build a 1.8 cubic foot box (14.5 inches on a side, internal) and have an F3 at 36.6 dB. Using 3/4" MDF would mean a 16" outer side length cube, which is right on the upper end of an acceptable size for me. I have a free-floating router and a circle jig, a router table for routing edges of boards, and a tablesaw. I'd plan to stuff the box with polyester filling to make it act bigger.


So, how does this plan sound? Would another driver, or another amp, be a better choice in this price range? Is a perfect cube a good choice, or are mismatched dimensions better? What am I forgetting?


Sorry I don't have links in this post; once I've got 3 posts I'll be glad to come back and post links to things.
 

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Quote:
Originally Posted by unhappy_mage /forum/post/15529362


I'm looking to build a small amplified sub that will fit in my apartment, and give some more oomph to my system. I could spend $400 and a bit on this project.


I've done some research on this, and helped my brother build a sub that's somewhat larger than what I'm looking for. Based on what I've found, a sealed enclosure will be easier to construct and model, and later on if I get more ambitious I can take the time to build a ported enclosure and move the driver and amp to it. So unless a ported enclosure really wouldn't be much more work or would have a huge benefit, sealed it is. After doing some reading on diysubwoofers.org, I came across the sealed sub calculator linked there, which has been very instructive.


Browsing through Parts Express, I found the BASH 500W amp and the Dayton RSS315HF-4, which look like a good match for my situation. Modeling the driver in the spreadsheet shows me I could build a 1.8 cubic foot box (14.5 inches on a side, internal) and have an F3 at 36.6 dB. Using 3/4" MDF would mean a 16" outer side length cube, which is right on the upper end of an acceptable size for me. I have a free-floating router and a circle jig, a router table for routing edges of boards, and a tablesaw. I'd plan to stuff the box with polyester filling to make it act bigger.


So, how does this plan sound? Would another driver, or another amp, be a better choice in this price range? Is a perfect cube a good choice, or are mismatched dimensions better? What am I forgetting?


Sorry I don't have links in this post; once I've got 3 posts I'll be glad to come back and post links to things.

relative dimensions don't matter for a small sealed sub - just the volume.


don't forget to subtract the volume of the sub itself from box volume.


for music i would also shoot for larger sealed box and lower Q.
 

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For Music and a sealed enclosure, look for an Amp that has some PeQ control that's tunable such as the HPSA500 ro the Oaudio500w bash amp.


For a great musical sub, look at the DS1200 Servo kits from Rythmik audio. Designed for 1.8 to 2cuft and probobly the best $ for $ option for music.

http://rythmikaudio.com/DS1200ci.html
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by vasyachkin /forum/post/15530092


relative dimensions don't matter for a small sealed sub - just the volume.

Good to know. I *could* build a box with different dimensions on each side... but I'm glad I don't have to.
Quote:
Originally Posted by vasyachkin /forum/post/15530092


don't forget to subtract the volume of the sub itself from box volume.

Good point. I don't guess there's any way to determine this without actually having the driver in hand? I don't see it listed on any of the spec sheets.
Quote:
Originally Posted by vasyachkin /forum/post/15530092


for music i would also shoot for larger sealed box and lower Q.

So a box that's tall and narrow (say, 14x14 base, 24 inches tall--that's 2.7 ft^3) would be a good way to go? I see a lot of people building cubes, but I simply don't have the room for a 24" cube in my living room. I could make the box as tall as necessary (but I'd like to be able to move it, so weight becomes a limiting factor at some point) but the less floor space it uses, the better.


Hypothetically, could one mount a subwoofer off the floor? I have a cabinet that has a 20x30 flat top on it, and at least 2 feet of clearance until the ceiling. If I could put a sub up there and not get horrible side effects that would be good.
 

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Quote:
Originally Posted by unhappy_mage /forum/post/15529362


I'm looking to build a small amplified sub that will fit in my apartment, and give some more oomph to my system. I could spend $400 and a bit on this project.

If your budget is tight, you can consider our A300SE amplifier with GR Research SW12-4 driver. It is a servo based system that will give you a very low Q value for the system and compact size (1.8cu ft to 2.0cu ft) and yet it gives you a flat to 20hz response (-3db at 14hz). It is a plug and play system that you don't have to do simulation or know how to use EQ to extend the natural roll-off of sealed box from 35hz to 14hz. It is all handled by servo. That would be the best combination of the ideas from the above two posts.
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by mayhem13 /forum/post/15530133


For Music and a sealed enclosure, look for an Amp that has some PeQ control that's tunable such as the HPSA500 ro the Oaudio500w bash amp.

PeQ means an equalizer, correct? I don't see any amps in my price range that have that---you have to spend $400 on the amp alone for that. I may be able to expand later and add an equalizer in between my receiver and the sub, but I don't want to spend so much up front.
Quote:
Originally Posted by mayhem13 /forum/post/15530133


For a great musical sub, look at the DS1200 Servo kits from Rythmik audio. Designed for 1.8 to 2cuft and probobly the best $ for $ option for music.

http://rythmikaudio.com/DS1200ci.html

$490 is just a little steep for me. I'd rather spend $300 than $500 on this; $400 is the most I can justify to myself.


That said, if $500 will get me a substantially better sub that $400, so be it.


Thanks for the comments so far.
 

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Quote:
Originally Posted by unhappy_mage /forum/post/15530307


$490 is just a little steep for me. I'd rather spend $300 than $500 on this; $400 is the most I can justify to myself.


That said, if $500 will get me a substantially better sub that $400, so be it.


Thanks for the comments so far.

Links of less expensive kits is as follows: drivers (check out SW12-4), amplifiers (check out A300SE, a less expensive model without PEQ), and kit (check out SW12-4 with larger enclosure option).
 

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Discussion Starter · #8 ·
I missed this response earlier; I didn't expect anyone to post between my two posts.
Quote:
Originally Posted by Rythmik /forum/post/15530270


If your budget is tight, you can consider our A300SE amplifier with GR Research SW12-4 driver. It is a servo based system that will give you a very low Q value for the system and compact size (1.8cu ft to 2.0cu ft) and yet it gives you a flat to 20hz response (-3db at 14hz). It is a plug and play system that you don't have to do simulation or know how to use EQ to extend the natural roll-off of sealed box from 35hz to 14hz. It is all handled by servo. That would be the best combination of the ideas from the above two posts.

I definitely like the design of the servo based driver. It makes sense to have this kind of "force feedback" in the speaker, so it can compensate for unknown factors. And F3 of 14 Hz would be awesome.
Quote:
Originally Posted by Rythmik /forum/post/15531363


Links of less expensive kits is as follows: drivers (check out SW12-4), amplifiers (check out A300SE, a less expensive model without PEQ), and kit (check out SW12-4 with larger enclosure option).

Ah, thanks. I hadn't really read through the site until now.


Just curious---is there an advantage to buying a kit over separate components? A DS1200 is $180, and an A370PEQ is $349, but a kit with those two things in it (nothing else is mentioned) is $569--$40 more than the component parts.
 

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Quote:
Originally Posted by unhappy_mage /forum/post/15532389


Just curious---is there an advantage to buying a kit over separate components? A DS1200 is $180, and an A370PEQ is $349, but a kit with those two things in it (nothing else is mentioned) is $569--$40 more than the component parts.

$349 price is for nonservo configuration. I have a couple of customers using these amps to drive their own nonservo subs. In short, there is a $40 markup for servo configuration. A300SE is our least expensive amplifier. The output is only 70WRMS less and that translate to about 1.2db less output. To compensate for that, we recommend to use 15% larger enclosure volume to improve the efficiency. You still get same 14hz FR without any adjustment from your end.
 

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Quote:
Originally Posted by unhappy_mage /forum/post/15530267


I don't guess there's any way to determine this without actually having the driver in hand? I don't see it listed on any of the spec sheets.

theoretically there should be a spec for it as you should be able to design a box before buying the driver ( this is the point of having specs ).


in the case of that Dayton driver it probably should have been Vd ( Volume Displaced ? ) but the figure 736 liters is obviously wrong.

Quote:
Originally Posted by unhappy_mage /forum/post/15530267


So a box that's tall and narrow (say, 14x14 base, 24 inches tall--that's 2.7 ft^3) would be a good way to go? I see a lot of people building cubes, but I simply don't have the room for a 24" cube in my living room. I could make the box as tall as necessary (but I'd like to be able to move it, so weight becomes a limiting factor at some point) but the less floor space it uses, the better.

theoretically if you keep stretching it out taller and narrower you will eventually run into a problem.

http://www.physics.smu.edu/~olness/w...ipe-waves.html


select a case for pipe with both ends closed, that will simulate a long tall enclosure. if your speaker hits a pressure maximum you're in trouble. but for subwoofer frequencies this won't really become a problem until your box gets REALLY tall.


you could safely build a box about the height of a table and split the volume between dimensions any way you want.

Quote:
Originally Posted by unhappy_mage /forum/post/15530267


Hypothetically, could one mount a subwoofer off the floor? I have a cabinet that has a 20x30 flat top on it, and at least 2 feet of clearance until the ceiling. If I could put a sub up there and not get horrible side effects that would be good.

ok stop. now you're asking questions that are too complicated. there is not even an agreement in the industry on what is the best strategy for placing subwoofers.


one way to determine the best location for a subwoofer is by trying different ones. you may go that route.


but for a single sub the only classical locations would be either between the main speakers on the floor ( what i would do for music ) or in the corner on the floor ( what i would do for HT )


of course i have a better scheme but i will save it for my articles.
 

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Quote:
Originally Posted by Rythmik /forum/post/15530270


If your budget is tight, you can consider our A300SE amplifier with GR Research SW12-4 driver. It is a servo based system that will give you a very low Q value for the system and compact size (1.8cu ft to 2.0cu ft) and yet it gives you a flat to 20hz response (-3db at 14hz). It is a plug and play system that you don't have to do simulation or know how to use EQ to extend the natural roll-off of sealed box from 35hz to 14hz. It is all handled by servo. That would be the best combination of the ideas from the above two posts.

Have you got any FR qraphs of this design? I looked through your website and haven't seen anything. I modeled that driver in a 2 cubic foot box and I get an f3 of 69Hz. Sorry if I am sounding a bit negative.
 

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Quote:
Originally Posted by Canadian_Dude /forum/post/15537654


Have you got any FR qraphs of this design? I looked through your website and haven't seen anything. I modeled that driver in a 2 cubic foot box and I get an f3 of 69Hz. Sorry if I am sounding a bit negative.

Servo is an adaptive equalization system. It provides equalization to extend the frequency response based on enclosure size and other factors using a sensing feedback method. Frequency response simulation based on constant voltage output system is only valid for regular amplifier without EQ. The only thing valid for servo system from simulation is the max output SPL curve. I can understand why you are confused. The actual frequency response from our F12G is this page .


All subwoofers on the market with 20hz extension or lower use some form of equalization. The difference between servo and those EQ method (which I call static equalization) is best explained via the cruise control in cars. The early cruise control locks the gas pedal when you set the cruise control. When we go uphill or downhill, the speed cannot be maintained. Today's cruise control senses the actual speed and adjust gas pedal to achieve that speed regardless you are uphill or downhill. Both are called cruise control, but operates on very different principles. Which one is similar to servo and which one is similar to static EQ?


Why do we need to use EQ? I have explained in another post that the only way one can get a naturally flat to 20hz with a 12" driver in a 2 cu ft box is with a one and half pounds cone mass. In other words, it is "impossible".


Anyway, your simulation with f3 of 69hz is not quite right either. A more correct value should be around 40hz to 45hz. Please send me a PM about the parameters you use.
 
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