New Sub...Advice needed.

[rdrowley]

This happened a lot sooner than I thought it might. I am suddenly going to be able to buy a new sub! But...I need input. I think that I would like a sealed 15 inch and I was leaning toward the Dayton RS 15 incher, but I'm not completely sure. I was thinking a sealed 15 because I like low but clean sounds out of the sub. I currently have a 500W BASH amp from PE just waiting to push something, so I can push a decent amount. The problem is I have a terrible room for bass. Here it is:



The Hall usually becomes a bass trap and is usually very boomy. The stairs are an escape rout for the sound as well and makes things difficult. Then, of course, there is the other side of the room that is just a big open area where the kids play. The ceiling is 8 ft. I have several places to put a larger sub, so size isn't an issue that way, but it is an issue with the wife...

I have an amp that will allow me to run 2 subs if I want/need. I would like to keep the cost of the driver below $200, but if I get a large benefit with something more then I'll go with more.

Would the Dayton RS 15 inch in a sealed box give me enough?

Do I need 2 subs? I've never had 2 before, but it could be fun...right? The problem will be the budget...

Can I carefully build and port a box that will give me nice tight bass and allow me to drop down into the 20Hz area?

Thanks in advance for your help!

[brent_s]

Given your wish list, I would look hard at a pair of Dayton's RS315HFA-8, currently on sale for $119 each. They don't model quite as well as the 315HF-4, but they're closer to your budget. Build them as nice end tables on each end of the main couch. The nearfield listening position will take care of the output concerns of the large room. It'll also help greatly with the room's influence on the frequency response. Two 12"s have slightly more displacement than a single 15" with the same Xmax...output is a function of displacement.

Running some quick sims on the 315HFA-8, you can get an f3=35Hz and f10=20Hz before room gain in 3 ft^3 sealed. With even a modest bit of room gain you're looking at an f3 of 20Hz in room. Going ported around 3-4 ft^3 tuned to 20Hz will give you an anechoic f3 closer to 20Hz. The "optimum" (no peaking) ported box is more along the 7 ft^3 range, but the peaking with 3-4 ft^3 is rather broad and mild (<1db at most) so it shouldn't be objectionable.

The 315HF-4 models similarly, but with no peaking in the same ported box and only needs about 1.7 ft^3 sealed for a Q=.7071.

There's no reason a properly designed ported box can't sound just as good as a sealed box. Lots of discussions of this topic over the years...Google is your friend.

You'll need to do some soldering to use that BASH500 as a proper sub amp, IMO. As shipped, its rumble filter cutoff is ~30Hz with about a 2dB bump centered in the 37Hz area. See the instructions for converting it to something more useful like the stock BASH300/SA240 settings with fC=18Hz, Q=1 which produces a mild 1dB boost centered near 24Hz.

-Brent

[rdrowley]

I appreciate your input, but I don't really want to go with the 8 ohm versions of those woofers. I'm somewhat patient as I can't really do the wood working on this till spring, so I'll just get the drivers that are best. But I would like to keep the cost of the driver under $200.

I've got no problem modifying the resistors in the BASH 500W, I was thinking about doing that anyhow, but would really like to get the speaker I'm going to use first.

Anyhow, any further advice would be greatly appreciated.

[Dr.EM]

If you want to use the Dayton driver and want powerful bass to 20Hz (perhaps lower) then maybe this would be a consideration:

http://www.billfitzmaurice.com/THT.html

?

[rdrowley]

If you want to use the Dayton driver and want powerful bass to 20Hz (perhaps lower) then maybe this would be a consideration:

http://www.billfitzmaurice.com/THT.html

?

Looks interesting, but do you know anyone that has built one? I would need first hand opinions and how difficult it is to build.

[exojam]

If you go to the home section of his page you will see there is a forum in there. One section is a build threads which should have some information for you.

James

[justphil]

Without a doubt I think you could manage to build a THT with very little to no problems. Fitzmaurices site forum is extremely helpful with questions.

[rdrowley]

Ok, so after looking at some of the forums on this beast...it may be a bit too big. 18ft^3 may not get past the WAF. Actually, I'm pretty sure it wouldn't.

I'm not necessarily stuck on the Dayton RS drivers, so any suggestions on size/drivers/configuration etc. would be appreciated.

[JeremyG]

What is in the 4'9" x 3'5" area by the stairs? Would you be able to put an IB in there?

IB Subwoofer Forum

Jeremy

[rdrowley]

What is in the 4'9" x 3'5" area by the stairs? Would you be able to put an IB in there?

IB Subwoofer Forum

Jeremy

It is a storage area with the door on the 3'5" side. An IB is possible there with some minor modifications. Would you recommend a certain IB?

[cjd]

Ryan (------------k------------) built one of the Fitz subs. They're... interesting beasts. Not what I want out of a sub.

IB, if the location works, is unbeatable for sound quality. They go low quite easily as well. Tons of info on the cult site.

[rdrowley]

Thanks all. Just for further info. The space by/under the stairs is open and I can use it for a IB. Also from the hall opening back around to a little more than 1/2 way behind the TV stand is also open and a possible location for an IB. It sounds like behind the TV would be best, but does anyone have more input/feedback on different locations and wall height?

I've been doing a lot of reading on the suggested IB site (Thanks for the link BTW) and I really think I like this option. It looks like I need to use 2-4 drivers though. The Dayton IB 15's look nice, but they are similar in price to the RS 15's and I don't know which is better. I also looked at the AE 15's. Can anyone help me out with a choice here. I'm thinking I'll need at least 2 of them, so I've bumped the budget up a little.

[mackintire]

Consider building an easy button box with the RS315-4. (not the easy button max)

The sealed option is going be need the most power.

The easy button box would split the difference. (its a modified EBS design that does a great job of killing port harmonics)

The THT is going to be the largest and the loudest but will probably need some EQ to get rid of the booming

IB is another great idea if you have the room for it.

The following is a generalization. I would model all contenders before choosing a final driver.

AE:
15-X is a better RS315-HF
15-H is a better RS315-HO

All four of the drivers above have been tested in the Easy button box all four drivers work. I should note that for some reason the easy button box does not model dimensionally like the simulation. The designer has a modified simulation that closely approximates the actual measured box output.

For example: the box's port physically measures 78" but acoustically measures at 128".

[JeremyG]

As with any DIY speaker/sub build, research beforehand is best. The IB cult site is full of info, and probably has builds that are similar to what you could do. Check out the FAQ's first. You don't need tons of power, but you will need at the minimum 2 15's. Plus, if you build a manifold you can build with forethought and make it upgradable for extra drivers if you want/need down the road. Again, do some research, and if possible test measure the response at the areas you think you could install one. The only downside to IB is you can't move it around once you build it, so you have to get the location as right as possible. If you have the option, IB is really the best way to go, IMHO. Plus, there's no refrigerator size cabinets in the room for the wife to deal with...

AE used to have a package deal, IIRC. Lots of people in the cult used them with success.

Jeremy