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Discussion Starter #1
Hello. I'm in the early planning stages of a sub build, and am trying to decide between the drivers below (for Christmas :) ).
Dayton RSS390HF-4 15" Reference HF Subwoofer 4 Ohm $160 (probable choice)
Dayton DVC385-88 15" DVC Series Subwoofer $150
Dayton TIT400C-4 15" Titanic Mk III Subwoofer 4 Ohm $220

Room dimensions: 15'x20'
Music/HT: 50/50
Amp: Behringer EP 1500 (used)(don't have it yet, so advice on this would also be helpful)
Sub volume: 9 cubic ft. or so, ported
Sub location: rear corner (not ideal I know) next to end of sofa

I will go with a ported design. Dimensions will be roughly 2' tall x 1'-10" wide x 2'-6" deep. There is a HVAC vent right behind where it will be, so I don't want the port or driver to be in the back to avoid blasting the rest of the house (although I can close the vent if absolutely necessary). I'd also like to avoid having anything on top, because this will basically be an end table/cabinet. So, which ways should the driver and port be facing? Other design advice?

I'm leaning toward the Reference HF driver due to price. If someone tells me I really need the Mk III, I will probably shell out the extra dough.

I'm most of the way done renovating my HT room, and plan on doing a thread on that in addition to the sub build.

Thanks!
 

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My friend built a Dayton Reference 12" RSS315HF in an approx 4 cu ft ported box and man does that thing sound good. I'm not sure why anyone would pay more for the titanic except maybe for the extra excursion for movies, but at that point I think I'd go with an exodus audio subwoofer.

So my money would be on the Reference 15. I don't think it will disappoint you.
 

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Discussion Starter #3
I forgot to mention that I will generally be using low gain due to the wife (I forget the acronym y'all use). Also, I would like to tune it to 18 Hz or lower.
 

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Discussion Starter #4
My friend built a Dayton Reference 12" RSS315HF in an approx 4 cu ft ported box and man does that thing sound good. I'm not sure why anyone would pay more for the titanic except maybe for the extra excursion for movies, but at that point I think I'd go with an exodus audio subwoofer.

So my money would be on the Reference 15. I don't think it will disappoint you.
Thanks for the advice. The only Exodus I see in my price range is the
Exodus DPL-15 at $140. Any opinions on that vs. the Dayton RSS390HF-4 15" Reference HF? Any other suggestions on drivers or sub design? I am leaning toward a down firing driver. Appearance wise, I'd like to fire the port (probably round 6") out the back, but with the heat register back there, that may not be best. I am guessing, based on reading other threads, that to get the port length for sub 18 Hz, I will need to go long ways with the port tube, so out the front. Whichever way they go, should the driver and port be centered? If not, how far off center?

For grins I will mention that I am building all the cabinets in the room. A long credenza in front, under the wall mounted TV, a display cabinet, a dog crate and the subwoofer. The dog crate will be at one end of the straight sectional, and the sub at the other. The will be similar in size and appearance. Maybe I'll add a porthole to the crate to match the sub port.:T
 

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You'd probably be better off building with the Dayton driver rather then the Exodus DPL due to its higher Qts, as you'll be able to create a system with Qtc around .5 or .6. I've used the Dayton HF drivers in as small as 2 cuft and it really does sound nice, especially for music.
 

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Depending on how much output you want, the Dayton RSS390HF will do well in 9 cu. ft. tuned to 18 hz with a pair of 4" flared ports 21" long each or one 6" port 22" long. There is a sub build with this driver here:

http://www.hometheatershack.com/forums/diy-subwoofers-sealed-ported/21025-rss390hf-4-bash-300-sub-build.html


The sub will take 300 watts to reach Xmax. The Titanic-15 will go louder and lower with 800 watts. Both subs need a hi-pass filter at 18 hz to protect the drivers from over excursion at the lower frequencies.

390 Titanic.JPG


Exodus DPL-15 at $140. Any opinions on that vs. the Dayton RSS390HF-4 15"
The DPL-15 is an IB sub, not what you want for your application.
 

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Discussion Starter #7
Thanks, Mike. I've now played with WinISD a bit. It's very cool. I guess people have found its modeling to be pretty accurate?

For some reason, the curve I got for the Titanic was not as flat as yours using the parameters you specified.

I modeled the Titanic and the HD (gray) and HO (orange) versions of the RSS390 along with the Titanic (green). The HO has higher SPL between 18 and 21 hz, but has a dip at 25. I'm not sure what the impact of the S curve vs. the rounded curve will be on the listening experience.
 

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You may have entered in your TS parameters slightly different than he did. As you can see the titanic is only a benefit if you run more power model the titanic with 300 watts vs the reference 15 at 300 watts if thats the amp you're planning on getting so you can see how they'll compare for you.

As far as the reference HO its basically the car verison, it models similarly but in a much smaller box, it does however require quite a bit more power to reach the same output. I wouldn't recommend using the HO for home use unless you just had to have a much smaller box than most of the other subs would allow.

And yes the DPL-15 is not really intended for use in a box it is an infinite baffle sub and would not be comparable for what you are doing.

edit, didn't see that you were using an ep1500, so a sub that handles more power could be a benefit.

Right now I see that the Titanic 15 is $220. for $220 I might lean more towards the exodus audio shivax2 for $198 or the Tempestx2 for $220. I like the Dayton Reference subs, I feel the represent a great value and have great sound quality but once you go past the $200 mark I think Exodus Audio or CSS or a lot of the other sub companies begin to offer a better value.

TempestX2 15" > Titanic 15"
 

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Discussion Starter #9
Thanks for all the advice, guys. I've purchased the RSS390HF. I guess I will end up getting one of the bash plate amps for the ease of adding the high pass filter (compared to the ep1500). I have space for about an 11-12 cu. ft. box (2'wide x 2'tall x 3'deep). It is going at the end of my theater seating. To maximize volume in the space I will probably not make it down firing. So, I'm trying to figure out where to put the driver and the port. The only surfaces that are not up against something are the top and front. On the side away from the seating is a floor to ceiling drape in a 6" space between the side of the sub and the end wall. Would it work to put the driver on that side, or would the drapes absorb too much of the sound? On the side towards the seating will be about a 2" space. Would the driver work there? If you guys say the best options are the top and the front, which should go where? It seems like a bad idea for the port and driver to both be in the front, although I know some subs use that design. I would think there would be some out of phase cancellation between the driver and the port, but maybe they tend to produce different frequencies?
The port tube will be about 15" long, so I think it could go out the top or front (or side).

I have a slightly wackier question. My theater seating has some space behind it (between the back wall and the seat): about 7" x 12" x 8' (4 cu. ft.) I could build a box to go in that space that would connect to the main part of the sub box. Would that help me get lower frequencies? I would think a long skinny box like that would have some strange acoustic properties, so that I can't simply increase the box volume in WinISD!
 

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I forgot to mention that I will generally be using low gain due to the wife (I forget the acronym y'all use). Also, I would like to tune it to 18 Hz or lower.
Just go with a 2'x2'x3' enclosure with a 29" 6" OD port. This will put you around the 14.9Hz area, and you can probably skip the HP.

The port can be on the same surface as the driver. You will want to keep the rear of the port at least it's ID from any other surfaces. I would put the port up top, and the driver on the open side though. ;)

I have a sub (two actually) with that driver at 315l, tuned to 13.8Hz down-firing with no HP (signal is flat until the 3Hz filters kick in.), and it(they) have been running fine (and hard) for over 3 years.
 

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Discussion Starter #14
I think I will go with the driver and ports both on the front, so it will function better as an end table. After starting to lay it out, I quickly saw why Mike said 4" ports. There isn't room for a 6". Well maybe there is room, but it would be close to two sides. I've read in this forum that the back end of the port should be at least its diameter away from anything inside the box. The 4" ports come closer to achieving that, and the layout is symmetrical around the vertical centerline of the front, which is more pleasing to me. However, even with 4" ports I can't achieve that, particularly with radiusing the port ends and a driver grill that is larger than the driver. Will it be okay to angle the ports such that the inside end is closer to the center of the box than the front end? It would be an inch or two over a 20" length.
 

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I think I will go with the driver and ports both on the front, so it will function better as an end table. After starting to lay it out, I quickly saw why Mike said 4" ports. There isn't room for a 6". Well maybe there is room, but it would be close to two sides. I've read in this forum that the back end of the port should be at least its diameter away from anything inside the box. The 4" ports come closer to achieving that, and the layout is symmetrical around the vertical centerline of the front, which is more pleasing to me. However, even with 4" ports I can't achieve that, particularly with radiusing the port ends and a driver grill that is larger than the driver. Will it be okay to angle the ports such that the inside end is closer to the center of the box than the front end? It would be an inch or two over a 20" length.
It would probably still be better to use the 6" port even with the limited distance. Remember you are going to be putting the port into the baffle so you would lose 3/4 to 1 1/2" on that alone.

You could easily make an angle. Just cut an angle at the distance you want to turn it at.

Then you can flip the pipe around and seal it up really good to create a joint. It's not perfect, but if your velocity is low enough it should work. If you have a miter saw. Use that to make the cut.
 

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Dayton DVC385-88 15" DVC Series Subwoofer $150
This is one of two Dayton drivers that works with the Bill Fitzmaurice Tuba HT. That design would be something to strongly consider if you don't mind a good folded horn design. There are lots of people going nuts over that design right now around the net, and for good reason.
 

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Discussion Starter #17 (Edited)
Thanks again for all the advice, guys! I've been all over the place with design ideas so far. I mentioned before that I have space behind my theater seating adjacent to where the sub box will be. I would like to take advantage of the space for an external port or just box space to get larger volume if it is worthwhile. The space is about 7" x 12" x 8'. Worthwhile?
 

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Discussion Starter #18
I've been obsessing on this project for weeks now, thinking of different ways to make a larger enclosure fit in the space I have. I saw someone's wine barrel project, and it gave me the idea to disguise the box as a steamer trunk, or get an antique trunk and modify it. My wife nixed that idea, but thought a trunk would be good to disguise a dog crate. I am pretty settled on doing an end table design now. I will build a box, and then build a table to sit around it. I'll paint the box flat black, or cover with fabric. The driver and round 6" port will be on the front, and I'm thinking of hanging some black fabric loosely in front of that. I would think that will impede the sound less, especially from the port. Any thoughts on that, or fabric recommendations? I was trying to figure out ways to maximize the box volume (angle the sides, so it is larger in back; use the adjacent space behind the seats...). My 12 year old son saw me playing with REW, and asked what I was doing, and I explained it to him, and explained and showed him on REW what a difference a very large box makes. He said, "Why not just use an equalizer"? Why not indeed? I did a little modeling, and saw that it should be easy to match the curve of a 11ft^3 box with 8ft^3. Of course, I will lose a little SPL overall, but I don't think that is a problem. A hundred bucks for a BFD sounds like a bargain, rather than building a convoluted box shape. Right?

I was also wondering about bending 6" PVC pipe, so that the internal port end is at least 6" from the box sides. I found a thread about bending 4" by heating it with a torch. I suppose that would work for 6" too, especially since I don't need much of a bend. I'm figuring that a nice gentle bend is going to be better than a sharp one.
 

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I did a little modeling, and saw that it should be easy to match the curve of a 11ft^3 box with 8ft^3
As long as:

1. The amp can supply the necessary power at the boost frequency. A 3 d boost requires twice the amplifier power.

2. The driver has the necessary Xmax to deal with the extra excursion there will be at the boost frequency.
 

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EQ is best left to a last resort thing IMO - if there's any possible way to get the box up to the size it needs to be, I'd do that first. As mentioned, you can run short on amp or excursion fast if you end up having to apply too much boost.
 
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