rls15 sealed

**fumoffu** · **10-22-07, 10:04 PM**

I am thinking about putting together my first DIY subwoofer. A sealed enclosure looks like a good one since its hard to mess up too much, don't have to worry about tuning and some other things. I found a nice speadsheet from diysubwoofers.org to plug in differnet speakers to see what they'd look like. This rls15 really got my attention!

If the speadsheet it right and I understand most of it the the performance of this element in a 10 cubit foot enclosure rocks! Because the Qts is very high (0.953) to get things to work out I needed to plug in a 1.09 for Qtc to get SS's recomented box size and everything to work out. Here is the graph I got:

Is this correct? This looks really good to me. Is it? With the SS element saying it can use 2000 RMS watts, a bridge Behringer EP-2500 would work really well with it too?

So how am I hoping to use this? Well it is from media room, lots of casual TV watching, some serious movie watching and some gaming. The room is 20x20x8ft in my basement. I ussually listen to movies between -10 -20db below reference. The other reason I am hesitant about a LLT or a ported design is I am in a end of unit townhome. I think being in the basement 7ft under gound level with 3 concret walls helps me not bother the neighbor too much, I don't want to push my luck with alot subsonic frequencies.

What advice do you guys have for me?

Thanks!

**Geoff St. Germain** · **10-23-07, 12:06 PM**

Well, the great things about the RL-s15 are the linear motor, which Ilkka has shown on his testing it amazing for reducing distortion, the massive excursion and the price. The bad thing is the very high Qts, which IMO winds up being a pretty significant deal breaker for home audio. IMO, if this driver had a lower Qts (in the vicinity of 0.5) this would be the king of subs for DIY guys.

**Ricci** · **10-23-07, 01:16 PM**

I looked at this driver for a while too, but it just doesn't seem to model very well...

**fumoffu** · **10-23-07, 01:22 PM**

As I said I am a noob at this. If I modeled the thing correctly that SPL graph looks good to me. Is it not? I guess a high Qtc in a design means there is going to be to much distortion/harmonic/delay or something that would cause poor sound quality. There are just so many numbers that I am just starting to understand with choosing an element.

**warnerwh** · **10-23-07, 03:59 PM**

If mostly HT and games then you may be better off with ported. A ported design is not difficult. I can say that because I'm no wood worker and made a huge one earlier this year with help from the experts. I just did another ported too and they both kick *** like I've never heard before in 35 years of audio. Both use the SS RL-P 15". Btw Mike at SS will honor old prices til the end of this month. The RL-P 15 is only 280 that way, after that though it goes to 335.

For your size room I think I'd go with the SS 18" or 2 15's. This way you won't run out of steam. I use one 15 in a 12x20 room opening into a kitchen and find it adequate and normally over kill is the word of the day for me. Btw having 2 dimensions at 20' means your room modes will be pretty bad, or double what they could be. You should consider the Behringer feedback destroyer and or bass traps.

**fumoffu** · **10-23-07, 10:59 PM**

Quote:

warnerwh wrote:

If mostly HT and games then you may be better off with ported. A ported design is not difficult. I can say that because I'm no wood worker and made a huge one earlier this year with help from the experts. I just did another ported too and they both kick *** like I've never heard before in 35 years of audio.

I am still not convinced that a ported subwoofer is best for me. I guess almost all of the ports I have seen are big things with tunes near the teens. With my desire to not have strong subsonic, I am not sure it's needed. *sigh* Sucks trying to be responsible and not shake the neighbors house too! But I guess a port could make it pretty level to 30 Hz though... hrmm. I am fairly hand around the house and decent with powertools and such. I'd could build the things to my satisfaction if not the first time then the second. My hesitation is with knowing whether I have designed the thing right and knowing its functioning proper before I blow the driver or something.

Quote:

For your size room I think I'd go with the SS 18" or 2 15's. This way you won't run out of steam. I use one 15 in a 12x20 room opening into a kitchen and find it adequate and normally over kill is the word of the day for me. Btw having 2 dimensions at 20' means your room modes will be pretty bad, or double what they could be. You should consider the Behringer feedback destroyer and or bass traps.

This all sounds like good stuff. My current sub sucks so much I can't even notice the room modes on my SPL meeter. There is a closet in one corner and a soffet to help break up the the square. Some base traps and sound treat ment are in the long range plan but I first need somethign to trap

What about the RL-p18 or 2 RL-p15 in a sealed enclosure.

With the RL-p18" in the recommended 7 cu ft enclosure with a Qtc of .775 resulting in a F3 of 31.1 and about -8.5dB at 20 Hz. A RL-p15 in the recommend 4.5 cu ft gets us a Qtc of .67 with a F3 43.6 Hz and then at -12dB at 20 Hz. Presumable using 2 15" in the same box with need a box that's twice as big and resuld in a +3dB gain in SPL. Can't the frequency responce be straighted out a bit more to 30Hz with some kind a EQ type thing?

If I am unhappy with the sealed I could always build the LLT with either of these elements.

**Geoff St. Germain** · **10-24-07, 07:17 AM**

Quote:

fumoffu wrote:

What about the RL-p18 or 2 RL-s15 in a sealed enclosure.

With the RL-p18" in the recommended 7 cu ft enclosure with a Qtc of .775 resulting in a F3 of 31.1 and about -8.5dB at 20 Hz. A RL-s15 in the recommend 4.5 cu ft gets us a Qtc of .67 with a F3 43.6 Hz and then at -12dB at 20 Hz. Presumable using 2 15" in the same box with need a box that's twice as big and resuld in a +3dB gain in SPL. Can't the frequency responce be straighted out a bit more to 30Hz with some kind a EQ type thing?

I'm assuming you mean the RL-p15 here. There's no way to get a Qtc below .953 with the RL-s15.

**buggers** · **10-24-07, 10:30 AM**

I have the RLP-18 in a 7CuFt sealed box for the music side of the system.
Got Thunder?!?!?
Dont Be Scared Just Do It.

**fumoffu** · **10-24-07, 10:31 AM**

Quote:

Geoff St. Germain wrote:

I'm assuming you mean the RL-p15 here. There's no way to get a Qtc below .953 with the RL-s15.

Doh! Well I just edited the message so its correct and I won't look like an idiot...untill they get down here

**fumoffu** · **10-25-07, 10:53 AM**

Ok, so after playing with numbers and trying to get a better understanding of these things I think I am going to go with 2 RL-p15 (check it has p and I am talking about p

) and it's going to be still sealed. (can always build another box if I am unhappy) I still have to decide to go with 2 Ohms or 4 Ohms. The 2 Ohms version has a lower Fs and Qt, resulting in a system that is smaller with the same Qtc, but has a higher Fb. I was thinking about putting both of them in one box so it could be placed below my display, and projector screen when ever I get that.

I have borked my laptop with the speadsheet data on it it

I think I was thinking about putting the 2 Ohms in a box about 1.4x1.5x3 for 6.3 cubic feet of space inside. But I don't remember now. As some of the more advanced programs don't run on a mac I wasn't able to do the modeling for xmax and watts stuff.

Can I get any recommendations out there for a size?

Are there any benifits for putting the 2 in one box? I know with 2 separate boxes I can tweak the locations more. But I like the idea of just one.

There have to be some sealed box fans out there!

**ISLAND1000** · **10-25-07, 12:56 PM**

I'm a sealed box fan and I like your idea of a single speaker in a sealed box for a beginning project. Like you said, you can always get into a more complicated project if you feel the need.
You can add EQ with the BFD and with the Behringer amp you'll have all the power you need to power the sub even with the required EQ.
I'm not familiar with the optimal box size for that speaker but I think you can do a sealed box with EQ much smaller than the 10 cubic foot box you mentioned in your first post.

**fumoffu** · **11-07-07, 06:10 PM**

Well I started building it over the weekend.

It's going to be a little more then 1.5x1.5x3 in size. I am using 3/4" MDF from HD. I will double up the front and place a few braces in it. I have been working on installing some hardwood floor, and this is my first bit of wood working like this. The table saw made things pretty easy. MDF is so easy to cut compared to oak! Hopefully I'll have most of it done this weekend.

I am alittle hesitant to cut out the holes for hte elements until I get them. Or should I just go ahead with the aprox numbers provided on the SS website?

how accurate do the holes need to be?

**Bent** · **11-07-07, 08:57 PM**

I'm (still) doing a 23"x23"x43", "every outside wall doubled up" 3/4 mdf sealed box with two dual 4 ohm 15" RL-p's which will be wired for a total nominal load of 4 ohms. It should net at about 7 - 7.5 ft^3 after bracing and polyfill.
I'll drive it with my ADA 1200 and Eq it with my BFD 1124p.
I have high expectations of this project.

**ISLAND1000** · **11-07-07, 09:43 PM**

That's a great start! Get as much assembled as you can, wait for the drivers so you can fine tune the hole fit, and then proceed. Put some braces inside, braces are always needed at this level of power and driver size.

**ISLAND1000** · **11-07-07, 10:33 PM**

I just spent a few minutes with WinISD modeling 2 RL-p15s in your size box (approx. 6.8 cubic feet) with drivers and braces. It'll be an excellent combination using EQ to lift (increase) the bottom end of the frequency response. It DID sound like you were going to have an equalizer/feed back destroyer along with the amp.

**fumoffu** · **11-07-07, 10:48 PM**

Quote:

Bent wrote:

I'm (still) doing a 23"x23"x43", "every outside wall doubled up" 3/4 mdf sealed box with two dual 4 ohm 15" RL-p's which will be wired for a total nominal load of 4 ohms. It should net at about 7 - 7.5 ft^3 after bracing and polyfill.
I'll drive it with my ADA 1200 and Eq it with my BFD 1124p.
I have high expectations of this project.

That sounds pretty cool! Do you have a build thread or pictures? The out side of your box is much bigger then mine but you don't seem to get too much more volume. I just figured that the polyfill should more then make up for the bracing. But I never did any calculations!

I have high expectations for mine aswell!

**fumoffu** · **11-07-07, 11:04 PM**

Quote:

ISLAND1000 wrote:

I just spent a few minutes with WinISD modeling 2 RL-p15s in your size box (approx. 6.8 cubic feet) with drivers and braces. It'll be an excellent combination using EQ to lift (increase) the bottom end of the frequency response. It DID sound like you were going to have an equalizer/feed back destroyer along with the amp.

So after you have started to build the box its time to model it?

Well thanks for doing it. I was using some spreadsheet tool to run the numbers for my estimates. The one thing I wasn't able to evaluate is if there is any possibility for the drivers bottoming out or anything with all those watts the EP can put into them.

I don't think I will be getting the EQ for a few months. It's still going to be a HUGE improvement over what I currently have.

I just can't wait to get this thing fired up! It's going to be so awesome!!!

**Bent** · **11-08-07, 10:44 PM**

I don't have any build pics of mine yet, I started over a year ago, but the problem is I already have a reasonably capable sub in a 15" RL-p'd sub similar to another sub builders mondo ported AS-15. I'm using one dual-4 ohm driver wired in series for 8 ohms load on my ADA-1200 right now, giving it a restrained 600 watts total.
If this sub didn't exist, I'd have put a lot more enthusiasm into the new project, but so far, I have about 50 percent of it done - I still need to route and mount the two drivers to the front baffle, install two internal window-style braces in the enclosure, a couple of braces to tie the front to the rear, and debate whether to install my amp in the box or go outboard. Here's a pic of the existing single driver AS-15 copy I built.

Notice my RL-p has no logo... neither does it's sister that will join it in the new box.

**ISLAND1000** · **11-09-07, 08:25 AM**

Quote:

fumoffu wrote:

So after you have started to build the box its time to model it?

"

"The one thing I wasn't able to evaluate is if there is any possibility for the drivers bottoming out or anything with all those watts the EP can put into them. "

"I don't think I will be getting the EQ for a few months. It's still going to be a HUGE improvement over what I currently have.

I just can't wait to get this thing fired up! It's going to be so awesome!!!

The time to model it of course is before you build the box. That way you know what type of box and what size will best suit your particular set of requirements such as number of drivers, amplifier power, desired frequency response, SPL, amount of SQ, room size, box placement, box material, etc.
Without any EQ the two drivers will take lots of power but any modeling program cannot be counted on to be perfectly accurate. You have to be careful as you add more power. It'd be horrible to accidently
bottom or blow a brand new driver because you were too dam excited and not careful enough.
New drivers and new boxes have to be experimented with to determine where the limits are. Your box size is large according to the SS site recommendations. The xmax may be reached with less power than you have on tap with the EP. Just be careful.
Without the EQ your dual driver subwoofer won't reach nearly as low but it'll be an awesome beast in the 30Hz to 80 Hz range!
WinISD is a modeling software program you can download for free. It is extremely useful even
AFTER you build the box. I suggest you get IT or another box modeling program and experiment with one. There is a lot to learn about boxes and drivers and WinISD can help.

**fumoffu** · **11-09-07, 09:28 AM**

Quote:

ISLAND1000 wrote:

The time to model it of course is before you build the box. That way you know what type of box and what size will best suit your particular set of requirements such as number of drivers, amplifier power, desired frequency response, SPL, amount of SQ, room size, box placement, box material, etc.
Without any EQ the two drivers will take lots of power but any modeling program cannot be counted on to be perfectly accurate. You have to be careful as you add more power. It'd be horrible to accidently
bottom or blow a brand new driver because you were too dam excited and not careful enough.
New drivers and new boxes have to be experimented with to determine where the limits are. Your box size is large according to the SS site recommendations. The xmax may be reached with less power than you have on tap with the EP. Just be careful.
Without the EQ your dual driver subwoofer won't reach nearly as low but it'll be an awesome beast in the 30Hz to 80 Hz range!
WinISD is a modeling software program you can download for free. It is extremely useful even
AFTER you build the box. I suggest you get IT or another box modeling program and experiment with one. There is a lot to learn about boxes and drivers and WinISD can help.

Your help and advice is very much appreciated!!! My comment was a smart-arse attempt at humor.

I am a mac person so I have not been able to run WinISD, but with my G4 laptop dying, and just getting a intel I should be able to set up boot camp this weekend so I can run windows and stair at some pretty WinISD graphs!

I have been hesitant to unleash subsonics on my neighbors. Which is part of the reason I thought a sealed was a good comprise. Hrmm... but -10dB at 20 Hz is less then I was hoping for. Still 110dB is loud! I will have to do some experiments on how easy different frequencys transmit through the common wall. If it's lower then I expect I may have to build a couple of ported boxes soon.

There is the DSP1124P and the DEQ2496. I was thinking about getting the DEQ, but with that price I was putting it off for a bit. I'll have to do some searching to see what the actually difference would be for this ussage...

If the DSP will work just as well, that I may get that real soon.

**Bent** · **11-09-07, 09:41 AM**

You can't actually apply a shelving filter with the DSP 1124, only a parametric boost with a minimum center freq of 20 Hz. With the DEQ, you can apply a correction at the bottom end that rises in level with a decrease in frequency. The 1124 will be almost perfect, where the DEQ will be perfect. However, the magic that the REW program can do can't be utilized on the DEQ.

**ISLAND1000** · **11-10-07, 01:07 AM**

[quote=fumoffu;60519]Your help and advice is very much appreciated!!! My comment was a smart-arse attempt at humor. :QUOTE]

I got your smart arse remark and smirked inside at it.
But I'm over forty and I . . . . . ok I'm over fifity and I . . . . . . ok I'm over sixty and I'm supposed to be the one who either ignores the overly rushed attempt at levity or admonishes the young guy when he gets out of line with the humor. You see making sounds with expensive speakers placed in boxes you design and build has become an important lifestyle for some.
It seems that YOU too have been bitten by this same bug. Don't be alarmed. The side effects are few and the lasting effects may just add to your quality of life.
Yes get an EQ when you've saved enough money. The EQ will afford you the opportunity to not only improve the frequency response of your audio project but also waste much more of your increasingly important and valuable time.

**fumoffu** · **11-17-07, 10:26 PM**

I have been very busy this past week! Everything was delivered. Parts Express, SoundSplinter, and the Amp! Man the RL-p15 are heavy and very sexy, just look at it!

Most of the cutting is complete. This is what I came up with for the bracing:

I am happy with my circle cut outs with my MDF made jig for the front baffle:

I rounded it out too:

I hope this this is going to be string enough, it feels really solid.

**fumoffu** · **11-17-07, 10:37 PM**

Tomorrow I am going to caulk the thing in the morning. I am thinking that I would be able to put the drivers in until Monday after the caulk has cured. I just need to mount the binding posts, the t-nuts, and round out some of the exterior corners. I am not going to paint the beast until spring just too cold for paint to dry fast.... and I am impatient and just want to hear the beast!

I got the dual 4 ohm version and am powering it with the EP2500, so I think I am going to wire it like this:

http://www.crutchfield.com/learningc...4%2Dohm%5Fmono

so that it will present a 4 ohms load to the amp, to maximize the power output of the behringer. This correct?

need sleep now

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