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DUAL RL-P15 Build

10K views 50 replies 11 participants last post by  Owen Bartley 
#1 ·
Hello All,
This is my first post but have been looking around for over a year now. I have a pair of RL-P15 that I have built a ported enclosures for and I drive them with a QSC 1450rmx amp 2 ohm load a channel (4ohm subs). This setup has been working good but I feel I am leaving something a the table:huh:. I am now using enclosures that are 22 3/4W 22 3/4H 25 3/4 D with 1.5 inch thick walls. Have 2 4" ports out the back of each enclosure. I don't remember the liters of the enclosures were. If I remember the tunning was kinda high around the 20hz range. So You can see why I would like something different.

I would like to go with a LLT with a tune around 14hz (Open on that) I have plenty of room. I would like to go with 2 separate enclosures for ease of moving. I have room for 36" deep 32" high and 110" wide total outside dimensions. I have played around with WinISD but I have to admit I don't really know what I am doing. I don't normally ask for help but I want to make sure I do this right the first time. Any input I could get would be great.

Thanks,
Chris:T
 
#2 ·
Hi Chris and welcome to the Shack!

I agree... you can do better with those drivers.

I don't know much about designing the boxes and stuff... I had all these other smart guys help me with mine as well. However, you might check out my Behemoth thread (link in sig) and get some idea of the volume needed and a good tuning point for those drivers.
 
#5 ·
Hi Chris. I'm learning about LLT design so I'll put my 2 cents in here. I modelled your subs in WinISD and 11.5 cubic feet tuned to 14hz looks good. Tuning would be one 6 inch flared port 28.5 inches long. An 8 inch port would be too long. At 750 watts input power cone excursion is reached at 13hz. Hopefully someone else will chime in here as I'm not sure how big a LLT design is supposed to be. Let's call this a learning experience for the both of us!
 
#6 ·
So that Per sub? If so WOW that is big...lol Yah, I am trying to learn all this LLT and I found this is the place to do that at:T

Here is what I was thinking.......

O.K. Here is an idea I came up with. I took a look at Sonnies' build to get some ideas. I think I would like to go with 280L+ box for each sub with a tune around 12hz. I will use a 6" port. Now, I need to come up with some box dimensions. Now that is a long port I will have to try to work with. I can front fire the subs and port out the sides. With both boxes put together a total of 115" outside dimension that will leave me about 3ft clearance from my walls on both sides of the ports. That should work right?
 
#8 ·
O.K. You are right Mike I was not thinking on that one...:dumbcrazy:

Here is what I have come up with......

Inside box dimensions will be 20"H X 34.5"W X 34"D that gives me 13.54cuft of space now take out the sub @ 0.18cuft and the port with a length of 28.1" .53cuft that gives me 12.86cuft. I will run a window brace the with of the box and put 2 more the depth of the box. I will use 1.5 MDF for the front wall. The front wall will have the Sub and the port firing froward in the room. I will try to get a picture of me idea up today so you guys can understand better what I am thinking.

Now, I am not sure how to figure in how much cuft the window braces will take up so some help there would be great.

Does this sound better....lol:bigsmile:
 
#11 ·
At 750 watts input power cone excursion is reached at 13hz. Hopefully someone else will chime in here as I'm not sure how big a LLT design is supposed to be. Let's call this a learning experience for the both of us!
Well first off, there is no way that QSC will put out a clean 750W at any frequency, let alone 20Hz and below. Maybe 600W @ 20Hz?

Secondly, I actually have the T/S parameters of a Rl-p 15 DVC4 wired in parallel. Naturally they're different, so the sub will model differently.

It looks like you'll have close to 12ft^3 net? I think I'd go ahead and tune as low as possible (36" long 6" port) if you plan on keeping that QSC amp. Might as well gain a little extension since you won't be pushing the drivers too hard. If you ever plan on upping the power, then I'd tune higher.
 
#12 ·
Well first off, there is no way that QSC will put out a clean 750W at any frequency, let alone 20Hz and below. Maybe 600W @ 20Hz?
Thanks for chiming in Will. The above modelling was based on driver limits and not on the QSCs amplifer output. My opinion is it's nice to know what a subs potential is should you decide to use it.
 
#15 ·
Thanks for chiming in Will. The above modelling was based on driver limits and not on the QSCs amplifer output. My opinion is it's nice to know what a subs potential is should you decide to use it.
For sure.

Thanks for the input Willy. I don't want to leave anything on the table here. What amp would you recommend? EP2500? I can get that for a good price right now. Would you keep the same tune of 14hz with a bigger amp then?
Well, if you want to stick to 14Hz, then I wouldn't get a new amp just yet. You could build the new enclosures, set them up, and see what happens. If the amp clips and you want more out of the subs, buy a better amp. The EP2500 would indeed be a step up, or you could go another step up. Just depends.
 
#16 ·
Well I have updated my design. It will be a 15.8 cuft box net. I will tune it to 12hz so the port will be 29.1 in long. I went with a big box so I could start out tuning low. If I want I can always shorten the port to raise the tune up if needed.

This way I can hang onto the QSC amp and if it does not cut it I will get something different. Is there any other Amp I should look at other then the EP2500?
 
#22 · (Edited)
Unless his room is particularly large or he has very capable mains and likes to crank it, I don't see a reason not to.

Soho54 has his pair of RSS390 sonsoubs tuned to 13.5Hz...
The room is 2520cuft that is open to my dinning room and kitchen via a opening in the back of the room that is 7' X 9'. I have no trouble now filling that room with good bass. My mains are JBL Northridge 100 E-Series that I feed with a QSC 850rmx that gives 185watts from 20-20. The mains do very well keeping up now. I just feel that I am missing out some on the lower end. I figured tune low I can alway bring it up.

I went ahead and orderd the Crown XS900.
 
#25 ·
Well, I got the wood all cut and one box almost done. I ran out of heating fuel at 11 tonight and it is -10 so I can't work without it:mooooh:

Here are some pictures so far what I have done........

Sorry for the bad pictures I used my camera phone:sarcastic:







 
#27 ·
Well worked on it from 10am till 11:30pm and I have MDF dust in places our creator never intended :scared:

Got one box all closed up and the screw holes putty-ed. Man I don't know what I was thinking but I used way to many screws on the first box. Lots of work to get it cleaned up. Live and learn I guess:mooooh:

I plan to just give them a nice black coat of paint. Nothing fancy....

Anyway here are some updated pictures for your pleaser:bigsmile:













 
#30 ·
I hope you've got some help to move that to the listening position... looks like it's going to be a heavy one. I also like how you rounded off the edges of the holes in the bracing, nice detail.
Thanks Owen!

I have my 14 year old to help me when I get them done. I was able to work on them tonight for a bit. I work a lot so I have not had a chance sense Sunday:sob:

I have them all together just did some sanding and put some spot putty on them. Hope to put a coat of paint on them tomorrow:jump:

Got my Crown Xs900 on Monday. WOW is that thing built good! Not as loud as my QSC and it has 2 fans!
 
#32 ·
Well, Got them all sanded and filed. Got them in the house tonight and I will put some paint on in the morning......








Here is a picture of the boxes and my 2 boys for reference on how big they are. Thats Tyler on the left he is 14. Jacob on the right he is 8........... Do I belong to the big box club? :dontknow:


 
#35 ·
Well, I got them all done. Calibrated and tried some WOTW to check them out. First seen the lighting seen in the beginning clipped channel one right off the Bat:foottap:. Well that is not right did not have it turned up even to reference at that point and gains set at half.......hmmmmm. Turned up the sub level on the receiver because the crown amp has 1.4 volt input and my QSC had 1.15v. Did not think that would be a big difference but what the hay I will try it. Played same seen again same thing only this time I noticed that the sub on channel 2 was barely working..... at this time I was like :mooooh:. Pulled the subs out double checked all connections and everything was fine. Put my BFD in line to check the output of the receiver set it so that I would stay out of clipping at my normal listing level. Tried again same thing:wits-end:. At this point I was thinking I had a bad amp. Went to bed went to work and when I came home tinkered with it again only this time I have no channel 2 at all. Hooked back up my QSC 1450 and BINGO everything is good. I have a bad Crown amp right out the the box:rolleyesno:

Now after my small rant My feelings on the new boxes........... WOW I can really push them allot harder then ever before with out clipping the amp. Music sounds much better. I can feel it. Had a blanket laying on the floor about 5 feet away and it was blowing the blanket around.:yay:.

I'm going to call Musician's Friend now to find out what to do with that Crown amp. I have to say It put a bad taste in my mouth but I am willing to try again. The only problem I see is that the amp is now discontinued on there web site:huh:. I hope they take care of me.

Here are some before and after pictures of my setup. That is a Samsung 62in DLP TV for reference on how big the boxes are......

BEFORE



AFTER

 
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