Sonotube RL-p15 Project with questions...

**bigguy** · **04-01-07, 09:03 PM**

Howdy,
I have been lurking for some months now and have read a huge number of posts from this board. You guys are tremendous support for folks like me who want to try their hand at Speakers. I have a friend who has made quite a few and even built the "DIY" Watt Puppy's which I now own. I find that it is a true sickness that can only be satisfied by making another speaker. Unfortunately, my good friend and all of you have given me the courage to try and build one.

I have come to realize that there are alot better speakers out there to be had than what is available to the masses without paying a second mortgage to get them. Build them.

So.. I just bought the EP2500 and Soundsplinter RL-P15 to try to build a Sonotube subwoofer and I was looking for what would be the obvious pitfalls that a nOOb like me would make.

I am very experienced woodworker and have decent knowledge of acoustics so before I jump off of the deep end I would be happy to hear any comments you might have.

Thanks

Dan

**Geoff St. Germain** · **04-02-07, 10:01 AM**

Yeah, it's a sickness alright.

Anyway, I've been working on a couple of sonotube sub enclosures (more to follow). I don't think that there is anything particularly difficult about building this sort of enclosure. Since you're a very experienced woodworker there shouldn't be many pitfalls as the woodworking required for a sonotube subwoofer isn't particularly difficult. The only possible problem I could see someone making would be cutting a smaller hole before a larger hole on one of the endcaps and then realizing that you've cut out your center hole for your jig. The only difficult part I found was marking the tube to be cut to size as it is a little tricky, which is why I let my buddy do that part.

**bigguy** · **04-04-07, 09:51 PM**

WOW!!!

I just received the EP2500 today and am Very aggravated that I didnt wait to buy it. I have 50+ pounds of beautiful amplifier and nothing to hook it up to. Very annoying.

SO the Amp is gracing the Dining Room floor until I get the sub built.

I did notice that there was some "non-standard" connections on the back of it so I might as well get these straightened out while Im waiting on the Sub to get delivered.

My amplifier has a RCA connector to go to the SUB... I dont see one on the back of the Behringer EP2500. SO.. how do I wire the inputs? DO I use the TS connector or balanced XLR? How do I convert from RCA to one of those?

On a Dual 2ohm RL-p15, which output should I use?

Do I wire the sub in parallel or series?

There is a group of DIP switches... What settings for Subwoofer use should I set?

I apologize for all the questions but this is fairly new to me and I have nobody in my group of friends that believe me when I say Bose Systems can be bested by DIY gear so their knowledge is very limited as well.

Thanks
Dan

**Geoff St. Germain** · **04-04-07, 10:17 PM**

I can't answer all the questions, since I don't have that amp, but I can answer a couple.

You can use either the TS or XLR connections. You just need to either make a cable or get an adapter. I made a cable for my XTi2000 that is RCA male on one end and XLR male on the other. You could do the same with a TS connector as well. If you google RCA to XLR in google you'll find ones to buy and instructions to make your own from the parts if you want to do that.

You have pretty much two ways to wire that sub to use with your amp. You can either run each voice coil off of one channel of the amp or wire the voice coils in series and run it off of one channel or you can bridge the amplifier. If you wire the RL-P15 D2's voice coils in parallel you'll have a 1 ohm load which could damage the amp (not to mention your driver as the EP2500 is could deliver a lot of power at that voltage until it could b damaged.

I don't know anything about the DIP switches on that amp so you'll have to look at the manual. You're probably going to be able to set things like a high-pass filter and whether the amp is bridged and how the inputs and outputs are wired (ie channel 1 to both outputs, etc). You won't want the high-pass because it is probably going to be set at around 30 Hz. I had a QSC PLX-2402 and I believe it had off, 30 Hz and 50 Hz for the high-pass filters.

**Sonnie** · **04-04-07, 10:43 PM**

Hi Dan...

There's one thing for sure... you'll have an awesome sub when you are done...

Have you thought about a BFD? If you plan on adding one then you will want to plan cables according.

I suggest using an RCA to XLR to run from your sub pre-out to Input 1 on the BFD. Then from the BFD Output 1 to Input 1 on the EP2500 use an XLR to XLR cable.

When setting the DIP switches... DO NOT pay attention to the labeling above the DIP switches themselves...

...they are not labeled correctly.

Instead look at the manual or the label on the right side of the back of the amp away from the actual DIP switches and set them as follows...

You will actually only use one channel of the amp. Wire your sub in series for a 4 ohm load to the amp, which will give you 650 watts for the sub. If you ever decide to add another sub... you'll have another 650 watts sitting there for use... just connect a speaker cable to it, nothing else will have to be done.

Keep us posted on the project!

I did change your thread title to "Sonotube RL-p15 Project with questions..." and moved it to the SoundSplinter forum as well.

**bigguy** · **04-04-07, 11:58 PM**

Nice! Thanks for the info.

I do apologize for the idiot attack but when I looked at the back of the amp I saw territory I have never before surveyed.

I think I have enough information to carry on smartly and will post "progress" pics when I can get started... need the tube and driver... everything else is ready for the build. I was thinking to attempt getting the bottom plate made out of Granite about 1.5 inches thick but I believe that would pose too many problems with the rest of the build... In any case, Teak might be good as well.. I will have to come up off the pot and make a determination there but I have time as the guy Im splitting the 12foot tube with will not be able to start for another two weeks and he is picking up the tube.

Again Thanks
Dan

**slidell** · **04-19-07, 03:37 PM**

Quote:

Sonnie wrote:

Hi Dan...

There's one thing for sure... you'll have an awesome sub when you are done...

Have you thought about a BFD? If you plan on adding one then you will want to plan cables according.

I suggest using an RCA to XLR to run from your sub pre-out to Input 1 on the BFD. Then from the BFD Output 1 to Input 1 on the EP2500 use an XLR to XLR cable.

When setting the DIP switches... DO NOT pay attention to the labeling above the DIP switches themselves...

...they are not labeled correctly.

Instead look at the manual or the label on the right side of the back of the amp away from the actual DIP switches and set them as follows...

You will actually only use one channel of the amp. Wire your sub in series for a 4 ohm load to the amp, which will give you 650 watts for the sub. If you ever decide to add another sub... you'll have another 650 watts sitting there for use... just connect a speaker cable to it, nothing else will have to be done.

Keep us posted on the project!

I did change your thread title to "Sonotube RL-p15 Project with questions..." and moved it to the SoundSplinter forum as well.

Sonnie,

Question on using bridge mode on above amp? Would havening the extra 650 watts in use (1300

) be beneficial for added headroom/dampening factor? It would kill me to know one way or another when an extra 650 watts are just sitting there.

TIA, Mike

**Rodny Alvarez** · **04-19-07, 08:22 PM**

The EP 2500 at 4 ohm bridge is 2400 watts!! that's maybe too much for one sub.:holycow:

**WillyD** · **04-19-07, 09:46 PM**

Quote:

Rodny Alvarez wrote:

The EP 2500 at 4 ohm bridge is 2400 watts!! that's maybe too much for one sub.:holycow:

It'll never put out close to 2400W though.

Check out this post by Thylantr: http://www.avsforum.com/avs-vb/showt...&#post10333605

Quote:

You can guess on what 2 ohm/ch or 4 ohm bridge mode power is. Since this is an
amplifier based on a conventional power supply, don't expect power to double
when impedance is cut in half. I would estimate ~1800W RMS bridged
mode @ 4 ohms only if your AC line is a constant 117VAC, but this won't happen in
reality. If you did an RMS test on that amp, expect AC line sag. I'd probably
estimate 1200w - 1400w as the real power offered by EP2500 using 1% THD+N,
20hz sine wave test, less than the advertised 2400w.

**Jerm357** · **04-20-07, 01:58 AM**

Id say wire it in series and just use 1 channel on the EP2500 first(650w). If its not enuff for you,, then bridge that mutha.

Im using my RL-P15 D2 in a 8.5cf LLT tuned to 15.45hz and Ive been feeding it with an EP1500 in bridge mono (specs say 1400w but its probably more like 1100w-1200w) and its been doing fine but, that EP2500 will have a lot more power so be careful.

**slidell** · **04-20-07, 09:52 AM**

Quote:

Rodny Alvarez wrote:

The EP 2500 at 4 ohm bridge is 2400 watts!! that's maybe too much for one sub.:holycow:

It's not 2400 continuous watts that I would be looking for. I'm running bridged for greater headroom and dampening factor. I also run a fast blow fuse

I've always voted on way more power than you need as long as practical. Unless I plan on a second sub, I would rather the amp "loaf" in bridge mode during the 1812 Overture.

Cheers

**Blaser** · **04-20-07, 02:11 PM**

Quote:

slidell wrote:

It's not 2400 continuous watts that I would be looking for. I'm running bridged for greater headroom and dampening factor. I also run a fast blow fuse

Greater Headroom....right, Damping factor.... wrong, You can't have both simulateously.... Nevertheless, a weeker damping factor won't make too much difference.

Blaser

**slidell** · **04-20-07, 06:42 PM**

Quote:

blaser wrote:

Greater Headroom....right, Damping factor.... wrong, You can't have both simulateously.... Nevertheless, a weeker damping factor won't make too much difference.

Blaser

Ah, good point. I guess in a standard bridged amp you would halve the damping factor if you treat the voice coil and input circuits as a resistor?

**brucek** · **04-20-07, 09:54 PM**

Quote:

input circuits

?

brucek

**Blaser** · **04-21-07, 06:12 AM**

The strongest in Electronics is Brucek!!

Better ask him!!

Blaser

**slidell** · **04-21-07, 07:42 AM**

Quote:

blaser wrote:

The strongest in Electronics is Brucek!!

Better ask him!!

Blaser

But YOU answered...

Sorry Bruce, yep, my mistype..let's try output?

**Blaser** · **04-21-07, 06:06 PM**

I am glad to help..... but only within the limits of my knowledge.

**slidell** · **04-21-07, 09:09 PM**

Well here's one to think about. I think most would agree that lot's of headroom is good. My original thoughts were with a dual voice coil. Would it be better to bridge the amp with coils in series or mono drive each amp into its own coil for full power with no loss in damping?

This is how I'm driving my stereo sub but 4 Ohms a coil. I'm still debating which Splinter coil configuration for future Sono project.

**bigguy** · **05-21-07, 10:24 PM**

OK... Stupid question time....

What is the minimum the baseplate should be from the bottom endcap???

Im working with 20" tube and have a RLp15. This is very important as Im thinking about losing the baseplate and going with the Casters

However all I can get is a set about 2.75 Inches from the floor...

Im almost done with it and will post Pics as soon as Im done... It should look pretty run of the mill however, I did use automotive headliner for the outer tube... looks pretty good if I do say so myself. It is easy to get and seems to be one of the default colors for the stuff so it is in abundance in any Automotive Upholstery shop... The alternative would have been OZITE but that is another story...

Any help would be a boon... Thanks

Dan

**Geoff St. Germain** · **05-21-07, 10:30 PM**

I know that the default in the sonosub program is 3-1/8". 2-3/4" is probably ok, but if you want more you could just use some of the MDF or whatever you built the endcaps out of to make some small mounting plates for each caster to increase the height.

**Hakka** · **05-22-07, 12:58 AM**

The opening should be at least the same as the surface area of the driver.

**bigguy** · **05-22-07, 09:06 PM**

Well... It's all finished and I must say it looks pretty good.

I will post pics when I get then chance but it looks fairly "Vanilla" as far as a Sonosub goes... I think I did somewhat of a hybrid as I used some elements from various SonoSubs throughout the threads. I listed some of the highlights below but will answer any and all questions. Remember this thing has been untested and I still have to add the BFD and get the REW lit off to fine tune it however, It sounds wonderful as it stands. And I do mean "stands"

Here are some notes for those of you who are lurking like I did but were afraid to ask the questions for fear of looking like a Goober...to you I say... go ahead ask anyway, these folks on this forum will answer even goobers like me.

1. MDF is heavy... employ a friend whenever possible (Thanks Buggers)

2. You will be cutting lots of holes in this stuff... wear a respirator or dust mask... Ensure you work outside for the initial cutting... MDF is VERY NASTY STUFF!!!

3. Put those fancy expensive clamps away. There is a much simpler and time saving way to do it and allows you to keep working.

a. Place the end cap on the bench and center a leftover piece of sonotube on it. All your center holes are going to initially be the same size anyway so don’t spend too much time here...then put Poly-glue (gorilla or equivalent) on the base and on the first layer of the tube insert and then put the tube insert into the tube onto the end cap and then drill and countersink about 8 holes and put in coarse threaded 1 1/4 drywall screws... that will draw the insert down to the cap and make a good seal...then repeat and so on.
b. Once all the layers for that end cap are glued and screwed down, remove the piece of sonosub and wipe the glue off of everything as best you can.

This includes the piece of sonotube as you will be using it again…and again and again…

c. Take the end cap and set it on a flat surface...(I used the garage floor) add some weight... I had some pavers left lying around from another project gone awry and let set for about 2 hours...

4. I decided to go with casters similar to the ones that I saw on another post and I decided that I really like the idea of the “round ball type” casters so I went to several places to get them and ended up getting the ones sold at Home Depot…

They weren’t big enough (only 2”) but I noticed that the measurement was not the clearance but the size of the ball roller… the actual size was indeed 2.75 floor to suspended part. I still believed this to be too short and used Geoff St. Germain’s (thanks for the quick reply Geoff

) idea of making a “block” to elevate another ¾”. Initially I thought it would look goofy but I did some router work to it and made them as small as possible and they look pretty good.

Now the distance from floor to bottom end cap is about 3.5”. Perfect!

5. I used ¼ X 4” bolts with the T-nuts. Aside from having to enlarge the holes in the driver a slight bit this was pretty uneventful.

6. I saw on another thread where someone lined their tube with foam and it looked pretty nice so I tried to duplicate it…there is a vendor on eBay that sells this stuff called “foamexpress”. I ordered this (24x24x1" Thick Studio Acoustic Soundproofing Wedge Foam) from them and it seem to work very well…

7. The 6” port was a difficult one for me to find however, www.thrilleraudio.com has a very nice 6" port. Part Number PSP6-BKNT. I also added another 12” section to this (default is 17”) for a grand total around $45.00. Not cheap but very good quality.

8. I wired the RLp15 2Ohm in Series and used 10ga. Silver Strand (40+ strands). This wire is special as it has a coating of Kapton over the wire and then a layer of Teflon. I also covered it with braided Kevlar sheathing and heat-shrinked the ends. Once attached to the speakers, I attached the wires at several places with retainers and then silver soldered them to the outbound connections which were protruding the bottom. I was very happy with the wiring.

9. I applied the headliner (nylon with a foam backing) to the tube and then assembled the entire thing…

10. I of course went immediately to the HT room (living room for those of you wondering

) and once powered up, I selected Serenity (starting sequence)

, Revenge of the Jedi (nice THX intro)

, U-571 (sub sinking scene)

, and then a bunch of scenes from various SCI-FI movies as they tend to use sound to get the “larger than life” feel. (read as tons-o-base)

11. Total build-time about 20 hours.

I want to thank you all for your help with this as I was virtually a nOOb with HT…still am. This was a terrific first project and I must say that Im ready to start a Center Channel speaker soon…maybe tomorrow…

Special thanks goes out to Buggers, my brother and friend.

He started me out with this “speaker building” sickness that you all seem to have and he managed to get me attached to a fine therapy group who are all dealing with the same sickness albeit some more sick than others…

Thanks
Dan

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