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Discussion Starter · #1 ·
I am preparing to tackle my first sub project. I have been reading these forums and others for the last couple days and my head is starting to spin. I think it is time to ask for some help. I will start dumping all the information I think is relevant here, I am sure I will forget lots.


First off, I have a large room and a low budget. Budget is around $300.00 for the driver and amp. My living room is about 18'x18' BUT it is connected to my kitchen which adds another 18'x 28'. Ceiling slants up to about 12' in area where the tv is but is 9' in most places.


I am a pretty advanced woodworker, I have all the tools necessary so I am not too worried about the build.


I am not looking for perfection, just something to add to the movies we watch, listening habits are about 80/20 in favor of home theater. I have read that a sub should go down to 20 Hz, so that is the goal. I have no idea what my listening SPL is, hopefully someone can give me a hint on how to figure that out. I (read my wife) would rather just have the one sub, but if I get a good argument, maybe adding a second down the road is an option but don't count on it.


Given the low budget, I have been reading about some of the Dayton Audio subs, the Reference 15 seems to get good reviews, with either the Bash 300 or the Dayton Audio SA-240? Maybe a 12 is the best choice given the small amp?


I am drawn to the sealed enclosure just because it makes more sense to me, the ported enclosure seems like black magic but I can definitely be persuaded if that is the way to go. I am not too limited by size, the room is large and I plan on making it look nice so the wife should not complain too much. She even requested putting a table top on it and putting near the end of the couch. Not sure if that is a good idea.


So the questions:

1. Sealed or ported?

2. Suggested Sub/Amp combo around $300

3. Approximate box size

3. Is there a good project someone has already done that you would suggest looking at, I have no problem with being a copy-cat.


Once I get some advice there, I can start playing with WinISD, it just seems a little overwhelming at the moment.


Thanks for sticking with me, I look forward to any/all help.
 

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Hey Ian welcome to DIY!


First off, making a 'functional' subwoofer IS a good idea as a table so if you have the wife's approval and woodworking skills, proceed accordingly.


First thing we'll need to know is how much space you have to spare....length/width/height. If it's going to be an end table, take into account the seating arm height so it's actually functional. If you need to 'protect' the driver from little hands/feet or pets downfiring is a good option. Adjust accordingly the height as you'll need 'feet' to give the bottom of the enclosure clearance to the floor. Your budget isn't the best but if you're not considering the building materialsin the cost, we're good to go!
 

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"I am not too limited by size..."


famous last words. do not go pass start. do not collect $200. go straight to lilmike's cinema f20. ;-)

http://www.avsforum.com/avs-vb/showthread.php?t=1329971


perfect for the woodworker with a low budget who wants to blast it in a big room.


if that is too stupid big, do a search on tapped horns and look for one with a 25-30hz corner. they are also simple builds and really blast it.


infinite baffle is another option if you can cut a hole in the wall and have a room on the other side to serve as a giant sealed sub.


the small sealed sub idea is the least efficient and requires the most amplifier of all possible designs. its advantage is that it is small.
 

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Discussion Starter · #4 ·
Thank you for the welcome.


Regarding size. We have a sofa table at one end of the couch that is 26 inches high so that feels about right. I could probably go as much as 24'' wide and maybe 30'' deep. Smaller on the width and depth would be better, but that is the max.


Kids will be on the way eventually so maybe downfiring is the way to go Will that limit the output? I have some thick carpeting, would it have to have some kind of base? The space is out of the way so probably not


The one thing about the table idea is that it limits the placement to exactly 1 spot. And that spot would be between the end of the couch and the rear surround. I have read that placement is important. I also really like the look of a cube showing off the driver. Really torn here. What would be better; a bigger box in a possibly bad location or a smaller box in a better spot?
 

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Discussion Starter · #5 ·
LTD, correction...I am limited by size, apparently very limited by size. Cinema f20 will definitely be vetoed by the wife. I will research the tapped Horn a bit, see if I can come up with something creative. Infinite baffle is a no go.
 

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"correction...I am limited by size, apparently very limited by size."


lol. np. famous last words like i said. ;-)


as for spl, that is pretty easy...if you are a guy who is always saying "go ahead, blast the sh_t" that is higher spl than if you are a typical person who is saying, "damn, do you think we are disturbing the neighbors?"


the difference is roughly 20db diff. spec about 125 at the listening position for the former case, 105 for the latter case...


i'd say go for your spl requirement first, then go as deep as your budget and other constraints will allow.
 

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If you have an existing sub of some sorts or can 'borrow' one from a friend it will help greatly in determining what's the optimal placement. If so, try the end table spot and then move it around some. If you don't have access to a test sub, it's a crapshoot at best but it the location is a corner, you should get some nice boundary gain if nothing else.


If you decide to not use the sofa table idea/spot does that change your size restictions?

The space you indicated would do well for a 15" driver. A properly designed ported sub is going to give you the best ' all around' performance given your budget and room size.
 

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Quote:
Originally Posted by IanNJ /forum/post/20864288


Thank you for the welcome.


Regarding size. We have a sofa table at one end of the couch that is 26 inches high so that feels about right. I could probably go as much as 24'' wide and maybe 30'' deep. Smaller on the width and depth would be better, but that is the max.


Kids will be on the way eventually so maybe downfiring is the way to go Will that limit the output? I have some thick carpeting, would it have to have some kind of base? The space is out of the way so probably not


The one thing about the table idea is that it limits the placement to exactly 1 spot. And that spot would be between the end of the couch and the rear surround. I have read that placement is important. I also really like the look of a cube showing off the driver. Really torn here. What would be better; a bigger box in a possibly bad location or a smaller box in a better spot?

You could make this into a fairly easy ported build. Build a box to the dimensions you listed above out of 3/4" material, use a Dayton DCS450-4 18" woofer and simply use this 6" Flared Port Tube Kit at its full 17" length for an approximate 20hz tune. All powered by the 300W Bash plate amp, which has a built in 20hz high pass filter. Outside of going with a horn, this is by far the most output you will get for under $300.

 

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Discussion Starter · #9 ·
Thank you for the help guys.


First off, regarding SPL and LTD's point , ".if you are a guy who is always saying "go ahead, blast the sh_t" that is higher spl than if you are a typical person who is saying, "damn, do you think we are disturbing the neighbors?"


I must say first, hilarious way to put it, but it gets the point across and I hate to admit it as it makes me feel less masculine, but I think I am the worried about the neighbors guy, so the 105db is probably sufficient. That is not to say there won't be nights when the wife is out and I have had a couple beers that I won't want to crank it. In this case, what will happen, will the sub just go to a certain level and stop, will it distort, will it spontaneously combust?


Secondly, regarding Mayhem's question. I do not have access to another sub. And anyway, the more I think about it, the more I am drawn to the idea of a sofa table sub. I think I can make it look pretty decent so I will have to live with the placement. I am going to spend some time later tonight with Google Sketchup to see what I can come up with. I can say that I was inspired by my bedside table which seems to be a good size, but it is definitely not a cube, so I would lean towards a skinnier, somewhat longer box, maybe something along the lines of 26''Hx30''Wx18''D. Those would be outside dimensions so that would leave me with under 8ft3.


So, Jay, I really appreciate the model you did, but an 18 is sounding a little big given my new plan. I think I have read some posts about using a 15 in similar sized boxes?


So, I think I am making some progress with the plan. I am hoping the above information helps spark some suggestions. I would like to get an approximate box volume nailed down before I get too deep in Sketchup. Thanks again all.
 

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Safe to say with your proposed dimensions, a front or side firing design, ported and standard 3/4" construction materials and bracing, i would expect a net volume of 6 cuft which would be sufficient for most 15" drivers available. Downfiring would obviously impact the net volume substancially so take considerations. Given your budget the Dayton RSS390HF appears to be the ideal candidate.
 

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Quote:
Originally Posted by Jay1 /forum/post/20864466


You could make this into a fairly easy ported build. Build a box to the dimensions you listed above out of 3/4" material, use a Dayton DCS450-4 18" woofer and simply use this 6" Flared Port Tube Kit at its full 17" length for an approximate 20hz tune. All powered by the 300W Bash plate amp, which has a built in 20hz high pass filter. Outside of going with a horn, this is by far the most output you will get for under $300.

Not going to deny that, though I do have an option for a much smaller tapped horn right on deck that will run with that. Right at 24" by 36" by 12.75" externally. Cuts from a single sheet.




Here is the 1W compared to the model, with a Tang Band 8 I had sitting around. I recommend using a 10" car driver in this one if you can - adds about 6 dBs. A pair with the Tang Band 8s will exceed 115 dB at my couch.
 

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ian,


tapped horn is a good solution for a low budget design with good sound quality that works in a large room (doesn't need room gain).


search on google images for: tapped horn. scroll through the pics and post the largest form factor that you think that you could live with. that will give some idea of the direction to go.
 

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Ian,


lilmike's T6 looks like a great option....


If not, lilmike's anarchy tapped horn....


Or, Bill Fitzmaurice's Table Tuba....


You'll have to pay for the Table Tuba Plans, lilmike's designs are free.



The reason lilmike, myself and others say horns, is because of budget. With sealed or vented alignments, you may get more extension, but in my opinion, extension is not worth much without the capability to create clean, low power demand SPL. Horns can do this with little $$.


JSS
 

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Quote:
Originally Posted by maxmercy /forum/post/20868243


Ian,


lilmike's T6 looks like a great option....


If not, lilmike's anarchy tapped horn....


Or, Bill Fitzmaurice's Table Tuba....


You'll have to pay for the Table Tuba Plans, lilmike's designs are free.



The reason lilmike, myself and others say horns, is because of budget. With sealed or vented alignments, you may get more extension, but in my opinion, extension is not worth much without the capability to create clean, low power demand SPL. Horns can do this with little $$.


JSS

+1 on the T6! I am listening to jazz with one right now and it is beating hell out of the room. and I have yet to really crank it up as the kids are playing down the hall. It does a fantastic job with movies and can be easily driven with a small plate amp. Look into it, it fits in the room, hits hard, and with your wood skills will give you much beauty. Mine is corner loaded and everybody just stares in disbelief when I tell them all that bass is coming out of that box.


BTW. anything lilmike designs is likely to be well worth the effort and LOUD.
 

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Quote:
Originally Posted by Tominizer /forum/post/0


Any timing on the T6 thread



I have built a spot for an F20 but it looks like it may kill the space I need for the equipment rack

Patience.


I got a little side-tracked on some other stuff over the weekend. I will have plenty of time to finish things up later this week.
 

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Quote:
Originally Posted by LTD02 /forum/post/20864228


"I am not too limited by size..."


famous last words. do not go pass start. do not collect $200. go straight to lilmike's cinema f20. ;-)

http://www.avsforum.com/avs-vb/showthread.php?t=1329971


perfect for the woodworker with a low budget who wants to blast it in a big room.


if that is too stupid big, do a search on tapped horns and look for one with a 25-30hz corner. they are also simple builds and really blast it.


infinite baffle is another option if you can cut a hole in the wall and have a room on the other side to serve as a giant sealed sub.


the small sealed sub idea is the least efficient and requires the most amplifier of all possible designs. its advantage is that it is small.

Thats a good size sub box.


For me stupid big is:


Sixty foot long concrete pipe with a 15 foot diameter with ten 18" subwoofers located at one end of the concrete pipe.


I told some friends about that project and they said theres folks that have a good sound system at the business but you want to brag that your stereo has a business alongside it.



Of course its going to be problematic telling the wife that I considered and discarded the big concrete pipe that was seventy five feet long and twenty foot diameter in favor of the much "smaller" sixty foot length by "only" 15 foot diameter



If I can get past the roadblocks of negative WAF and cost then maybe thats my next project??
 

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Discussion Starter · #18 ·
Hey guys. Thank you for all the suggestions. Apologies for not posting sooner, a hurricane, followed by the wife getting surgery for appendicitis has totally consumed my time over the last week.


Anyway, after reviewing all the posts, I can say I like the idea of a tapped horn, however, it looks like it really only goes down to 30Hz, and then has a major dropoff in SPL. Messing with WinISD, it appears that a 15'' driver in a 6-7 cubic foot ported box would go lower with more SPL. This is modeled with the Dayton RSS390HF that mayhem mentions. Perhaps I am doing something wrong, but if I was correct, is there an advantage to the tapped horn?


After watching a few movies with my wife, I can definitely say that we do not listen loudly so I think just moderate SPL will be sufficient. I just want it to sound nice and tight and produce nice lows at moderate levels. I am even starting to wonder if something smaller with a 12'' drive would be more appropriate.


Thoughts?
 

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The RSS390HF is a great driver. You can use them in as little as 4.5-5 cuft and use multiples. It is probably one of the most value based drivers out there, especially if you can find it on sale. 2 of them should get you good, low distortion output from 25Hz on up, and 4 should give good output from 15-20Hz on up. 8 should get you very close to 10Hz at reference with low distortion.


If you want more output, the RSS390HF is a great match for the Cinema F20 horn, if you only want to build one or two enclosures.


It takes 2-3 sealed RSS390HF sealed enclosures to beat a single F20. The sealed enclosures will win below 20Hz if you do this.




JSS
 

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Discussion Starter · #20 ·
I am now starting to lean towards something like the Easy Button build with a 15'' driver (RSS390HF?) and the Dayton 240 plate amp. This build seems to be around the size I am looking for and seems to go to 20Hz and even below.


The problem I have now is that I am a bit mystified by the slot ports and this box is designed for 18'' drivers. I was hoping to limit the size a bit for the 15'' driver but I do not know how to calculate the size for the slot port. Is this available in WinISD?


Does this sound like an easy button box with the RSS390HF and a 240 amp is going to give me some good punch? Like I have said before, I am not looking to bring down the house. Any suggestions on how to modify the easy button design for this driver/amp? Any suggestions on other drivers in the same or lower price range of the RSS390HF? Will I need a high pass filter or does the amp provide this?


Thank you all again.
 
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