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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
 
#38 ·
Well, I just called and they don't have anymore:teeth:. They will give me QSC 1450 for the same price but I will take a hit in the power department. The crown gives me 1200 per channel @ 2ohm the QSC I would have to drive each voice coil separate at 450 watts each voice coil for a total of 900 watts. I don't know what to do. Have two QSC 1450 one for each sub or just get a Behringer EuroPower EP2500. They would sell me a new Crown but I would have to pay another $125. I need some input here:wits-end:
 
#42 ·
That's a pretty mean looking front stage. So you like the big ported boxes a lot better than your small ones? I've been leaning towards a smaller sealed sub for my next one, but maybe I'm thinking wrong. I guess the smaller box and the higher tuning frequency would give you quite a different feel than the ones you have now, and this is more a "better version" of what you had, rather than a totally "different" sub. Either way, great work, and best of luck with the bad amp, I hope they sort you out!

Edit: Did going to the bigger boxes give you a less boomy sound? Just wondering.
 
#45 ·
I like the big box Much better. Night and day difference IMO.

I have much less boomy sound. I have bass now that I did not know I was missing. I will try to get some measurements of the setup. I have noticed most that I don't have to have music or a movie cranked to get the output now. And that is with my old QSC1450 can't wait to try the Crown Xs900:jump:
 
#46 ·
Re: DUAL RL-P15 Build and the QSC 1450 amp

I was going to build a pair of the RLS-15's sealed and Mike told me they are gone for now. I wanted to have the finest bass I could get in my living room. He said I would need larger amps too....

I made a change in my wiring.....

I have two dual 2 ohm drivers in my cabinet. I wired all 4 of them in series which is now presenting an 8 ohm load to the QSC 1450. I'm between 700 and 800 watts to both drivers on a single amp. I watched a high impact movie with this new wiring change and listened to a couple of premium music videos, and the bass is still so incredibly clean using just one amp wired this way. The passive radiators help to reach those really low clean frequencies. The dual 2 ohm's Q are low enough to take advantage of this type of design.

I have the other QSC amp disconnected now and am ready for another subwoofer. I'm anxiously awaiting my order of two more RLP 15's from Mike. I'm going to duplicate what I already have built as my Rotel has dual sub outputs and dual subs are recommended for an optimal HT system. That will give me 4 15" RLP's and 8 passive radiators in two cabinets. I think I'll be extremely happy with this set up. As I've posted earlier, don't sell the QSC amps short because they do perform quite well.

Also something else I noticed, pumping out some really high spl with the QSC at the 8 ohm load, the fans never kicked into the high speed mode and were quiet! I was still able to acheive the headroom I wanted.

I've (my wife has) already blown a pair of drivers using the two amp setup I had before, so this should keep things down to a safe level as far as overdriving the sub.

Good luck with your projects,
Mike
 
#47 ·
The larger optimal EBS(LLT) box will best a sealed any day,both being well designed. At liberal SPL the large ported brings the best out of these RL-p drivers.

Only a few drivers are great for smaller sealed(a small group of very high Xmax ...Tumult,TC3000 and up,SoundSplinter RLs,JL W7(Fathom variant)),where they perform admirably.Still ported beats sealed,port gain cannot be denied.

From now on I think I will not build a single sealed! All will be ported.:R
 
#49 ·
Finally got to do some measurements tonight. Had to use 5 filters on the BFD but got it to look pretty good.



As you can see I had a bad null at 50hz. I tried some different stuff before I EQ'ed it but could not get much better. The only thing that has me a bit worried is that I had to do a gain of +16 to get it out.
I have my receiver crossed at 100hz to help the null at 90hz also set a very narrow filter of +16 to get that up. Do any of you think that having them 2 filters at a gain of +16 will hurt anything?

Also I had my mains running with the subs. Any suggestions on what you see would be great (Good or Bad!)
 
#50 ·
As you can see I had a bad null at 50hz. I tried some different stuff before I EQ'ed it but could not get much better. The only thing that has me a bit worried is that I had to do a gain of +16 to get it out.
I have my receiver crossed at 100hz to help the null at 90hz also set a very narrow filter of +16 to get that up. Do any of you think that having them 2 filters at a gain of +16 will hurt anything?

Also I had my mains running with the subs. Any suggestions on what you see would be great (Good or Bad!)
Nice job on the eq and that is some awesome extention! +16db is on the order of 300X power so it's definitely pushing it. Unfortunately there's not much you can do about a big room mode like this other than move the subs or move the couch. Definitely keep an eye on the clip lights of the amp!
 
#51 ·
Yeah, +16 is a lot of gain, but as long as your amp can handle it, you should be fine. I'd keep a close eye on it for the next little while, especially during demanding material, and if you do notice some clipping you can ramp it down a bit. Does the null exist everywhere in the room, or just the main listening position?
 
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