Scott's Dual RL-p18 'LLT' design/build thread - Page 9

Ill take a stab at switching the phase on just one sub. Almost lunchtime for me so I may have a chance before I bring one down tonight. Will it make difference which one is reversed? Ahh, Ill just try em and see...

REW time again.

Ive heard plenty about Chuck's EQ/HP filter thing but last I heard was that he was still waiting for the boards to come in. I am assuming that they are ready now?

Mmmmm....can't wait to have these suckers firing into the corners!

EDIT: Tried hooking up one out of phase at lunch. For some reason it wouldnt output anything when I hooked it up that way. Maybe the EP2500 doesnt allow such wiring methods...

Anyhow... for reference...I plotted just my mains. One with the 80hz xover. The other fullrange. Check out the lowend on these 281's!



You can still see the ringing at 25hz and 35hz. Must be room related. That and the short null at 28hz and the big one around 45hz....even with the subs off, they are still there. Hmmm, its gotta be the shape of the room and my location in it. I wonder if the forward firing ports (on the 281's) have anything to do with this. IIRC, the 281s are tuned ~28hz. Hmmmm.....

Woops! I freakin forgot...

This whole time I was just assuming that I posted my LP....hahaha!



This was taken standing on top of my tempest before the twins were placed.

Yep, the side surrounds are a little twisted inward towards the listener. All the surrounds are 3-way and they didn't sound as good pointing straight towards each other. Ive tried all sorts of locations in the room and the way I have it setup now is the most practical while yielding the best sound. Just gotta work on this ragged bass response.

Hey guys! I moved my subs this weekend. Got them firing into the corners now. I took lots of pics but when it came time to upload the pics...I found myself looking for the damned USB cable (really small version) and I cant find it anywhere. Ugh! So...just imagine the subs behind the speakers and tv now. Each one was turned a good 90 degrees and firing into their respective corners.

Im at work now and dont have the measurements online either...but I can tell you I have almost eliminated the problems. Still a little bit of a dip around 50hz but it is WAAAAAAYYYYY better now. Just took 3 filters on the BFD to bring things in line. Very nice. Ill have to upload the measured FR from REW. Looks and sounds much better. Although, Im going to miss the imposing nature of how they looked before.

Hey fellas...sorry for the lag.

Before you look at the new plots...here is a copy of how the FR was when I had them stacked off to the left of the mains. (so you dont have to go to page 8.)



Obviously this is not very smooth at all and there is a huge difference in level from one side of the room to the other.

Here are some plots of the woofers in the corners as they are now...


Oh, btw. Xover on all main channels and LFE are @ 60hz now. Had to kill that null. Subs are in-phase with mains. 180 phase resulted in worse nulls, surprisingly.


First is the un-EQd plot.

Dark green for straight ahead
Red for right ear
Light green for left ear



Not bad....not great but much improved over the old position. Notice there isn't a huge difference between ears now. Much smoother sounding FR. Not sure where the dips at 55hz and 60hz came from. They weren't there last week. Hmmm...oh well.

Next is the new position with the EQ Ive been using all week. 3 filters.

Purple is straight
Cyan is right ear
Gold is left ear



And here is a new EQ I made today (just measured) with only 2 filters.

Dark blue is straight
Turquoise is right ear
Violet is left ear



And here is the straight ahead comparison of the three

Green is un-EQd
Purple is 3 filters
Blue is 2 filters



Still had the amp gain up a lil bit higher than usual. The difference between analog stereo and fiber optical DD/DTS 5.1 inputs makes quite a difference. I had to level check movies by ear still. Sooo they might look a bit flatter if I had turned the amp gain down to where I had it before. I left it in "movie mode". Hehehe. Ill take new ones if you don't like these. Alrighty. Lemme know what you guys think.

I would if I could. My Harmon Kardon AVR525 doesnt allow for that kind of adjustment. It only has settings for center, surround, and rear surround in a Dolby mode. I still have a few others to try. I can flip them so the woofer is closer to the ground and not the port. A bunch of trial and error up ahead...hehehe.

Awesome low-end though, huh?

Yah, when it comes time to upgrade to HDMI capability...Ill prolly get a Yammy. Im Yamaha biased.

Thanks so much, Dan. Without your help I could never have built these huge, bad boys. Much appreciated.

Ahahahaha! Awesome!

I was running out of headroom on my BFD too fast. No boosts or anything. I just think my AVR runs a nice signal and it was way too easy to hit the clip light on it. I havent been having as much fun with these bad boys cause I was too busy watching the level meter and cringing at any dynamic/loud moments. (It hit me while watching LotR:FotR EE/DTS 6.1 - that scene with Boromir wanting to grab the ring at the Elvish city [Bah, its too early to remember Tolkien mumbo-jumbo ;D] and then Gandalf does that voice and the rooms shakes. I had to turn down the MV almost 6-7dB cause my BFD was lighting up like a Christmas tree. And got to finish the night with WotW without having to duck down the LFE -5dB like I used to... ) Totally needed to use the +4dB (from -10dB) button on my BFD. Lots of signal headroom on the BFD side. SPL is much higher and still, no clip lights from the 2500. With that and the newer FR from the new sub locations. Now, we are soooo rockin'.

New listening tests to follow...

Hehehe...aint that the truth. Ive been a little disappointed in the actual output until now. I knew I was just taking it easy as I dont want to break anything prematurely but still was wondering where all the horsepower was. Just didnt have everything tweaked just right. While using my Tempest I also preferred the "pro mode" on the BFD (+4dB button) but it was waaaay too easy to clip the 250w plate that way. Now that I have 10 times the power on tap this is a better solution.


Harmon Kardon AVR525. Awesome receiver, unfortunately it came out a year before PL2x was released so I cant do stereo back surrounds unless I use Logic7 on stereo sources. And no HDMI. Oh wells...its the best AVR Ive ever owned and got it for $500 instead of $1000, brand new.

Settings for my EP2500:

Bridged mode: on
Clip Limiter: off
Low-end filter: off
Gain @ 24 or the 12 o' clock position

Id rather have to use the level toggle on the AVR remote to control my LFE than to get up and fiddle with the gain on the amp. Thats just how I roll. This way seems to work. I wanted the ability to just let things fly on cooked LFE tracks instead of having to worry about levels and such. On movies that are tame, they just are or I can up the LFE up to +10dB if need be. Same for crazy LFE movies... -10dB if thats what needs to be done. Id rather just let them be and let crazy movies stay crazy and normal ones I can play around with I need to. *nods*

Ah, I was just gonna ask someone for that. Gonna have to try that one later ...with some care.


No no ...I know that. I just find it odd...maybe just surprised that I havent gotten that far yet. These things are loud! Last night, I think I got them louder than ever. Pushed WotW lightning scene and ch5 with no sweat. I dont want it to flicker or light up either. Not at all. Im just really surprised I havent done it on accident yet. Lolz! Maybe it will never happen....

With the BFD @ +4dB now...it may happen sometime. If never, the better.

ZZzzzzzzzZZzzzzz....

You brain scanner.


I forgot who posted it the first time. (Im thinking it was Mark Seaton) So Im definitely going to treat the 'fireworks' with lots of care. Something around 70dB of dynamic range or worse? Geez....Ill take it easy with the first few tries. *nods*

Thanks again, for the link. It was made for a thread like this.

Aww no! I cant get the download for the fireworks to work.

Anybody else have another link for it? Or maybe its cause Im at work. Hmmmm....

EDIT: searching for it comes to the same link from danley....hmmm...even a google search came right back to your post. *laughs*

If anyone has a FTP or something so I could get it...or email it to me. Just PM me. Thanks.

Yep. Tried again @ home. Still no luck. Darn. If anyone has this file I sure would like to download it somehow. Ill keep trying...

Some listening tests from last night...

Started the night off with Black Hawk Down. Wanted to check out the 'Irene' sequence as it has strong infrasonics. Loud 5hz content and Im always curious how the system will handle it. (For those unaware, this is a LLT with no hipass/subsonic filter. Just electronic rolloff where present.) The sequence sounded great. The pulses from the inside helicopters was fantastic! Good tactical presence. Very cool. Seemed like I could turn it up some more though. Not that it wasnt loud, just that it sounds so good I could keep turning it up. I think thats a good thing.

Switched that out for Episode 1. Time for the podrace again. Started off with the THX Cavalcade trailer...sounded awesome and more enjoyable now that I dont have to keep an eye on the BFD level meter anymore. I played it back a second time cause I still had the MV a little quieter from BHD. Now...as soon as I started playing the movie...it sounded a little tame. Hmmm....had to bump up the LFE on the receiver to +5dB (more on that in a bit) and totally rocked out during the podrace. I mean, it sounded freakin' awesome. The placement, EQ and now my sensitivity adjustment on the BFD made a world of difference. Watched a few lightsaber fights and finished when that space station gets blown up.

Now this is the really embarrassing part...

I got up, turned on the lights to go put in another dvd and I have a glance at the amp (its on the floor infront of my tv) and I see something that grabbed my eye. Oh, this is embarrassing. The negative wire for the sub on the left had fallen out. So this must mean while playing Star Wars that I had only one sub rockin'. Omfg...so embarrassing. That justified the reason that I had to bump the LFE up +5dB.

*sigh*

I need a new wiring scheme. I use a 14awg wire for the positives (both sides) and 16awg wire for the negative. Its just what Ive had around as I thought maybe the single 14 gauge wasnt going to have enough power going through it. I dont know where I got the idea but thats what I thought. Maybe I should just solder the ends for each sub onto a single pin connector so I dont have this problem cause the wire has wiggled out about half a dozen times since Ive owned these. Hmmm...

After having a big sigh and re-hooking up the wire. I decided not to re-watch Ep1. Can only take so much of it in a day.

Popped in Titan A.E. Whoooo! This movie REALLY rocked. I know its got a crazy LFE track, Ive always used it. One of the movies that could really sock it to my Tempest. Im sure it hated me for the pounding it got from this dvd. Theses guys handled it with ease. In fact, the new placement (and BFD adjustment) really helped out a lot. It went from sounded (in the old position) so-so..a bit better than my tempests, louder and deeper...but not incredible. To "OMFG...turn it down before the house crumbles!". Seriously! When the alien ship blows up the Earth. Holy cow! I had to back down the MV just a tad cause I was worried I might break a window or two. It sounded great though, zero distortion that could be heard. Just pure, couch shaking bass. Im in heaven. It was almost scary. I sat there dumbfounded as the Titan AE title came up cause I was in such awe... The craziest bass I had heard yet...even scarier than WotW. Yup! I couldnt stop there, I had to check out the beginning of the ice field sequence. Holy sheeeit! Its never sounded like this before! Woooooot! When the two ice chunks start coming into each other....holy frickin' cow. Wow. Who needs bass shakers? Ahahahah! Wow...I hope you guys with big-ass subs get the same feeling.

I ended the night with a big ol' smile on my face.

Now I just gotta keep these wires from wiggling out anymore... *nods*

Yeah but I need two wires to go into each post on the back of my 2500 cause its bridged. The problem is that the binding posts dont want to fit two wires together on a single post. Its a tough fit. The bigger the gauge, the worse it is to actually keep them on the post. These posts dont look like the typical 5-way variety. Thats why I thought I should just pick up a pair of pin connectors and solder the amp-end of the wires together so I can fit the single pin for each post without having to cram the bare wire on there. Just a thought...its what Ill prolly have to do. Doesnt sound too hard at all...just gotta go to the store and pick up some pin connectors.


Thanks! Wish I could invite you guys over to hear it for yourselves... Fun stuff. Having a lot of fun with them in the new position and with the BFD (sensitivity) fixed.

Ah, yes. I think that will do. A 100' spool will be enough for them both if I twist them and crimp them the same way you did, Steve. The 16awg wire was just for the negative posts on both and I didnt just use half of the 16awg wire. I twisted them together as I did with the 14awg for the positives....so they were thicker than the rating, I just dont know the conversion. Thats the four sets of wires hanging out the back in the pictures I posted. In the subs w/ tv pic you can really see them all. I like your idea better.


I hope so cause it said on PE that they go up to 10awg. I trust you though, Steve.


Heheheh...Ive used Titan A.E. as demo material for years. Ever since it came out. Awesome bass in the movie, very wide bandwidth. Every laser blast and such goes into every octave of the bass frequencies. The opening Earth destruction is quite a thrill now. Before, I could never get that rock-your-world feeling from the theater with my 250w Tempest. This is a big step up. And I wont go into the whole ice field part...holy sheeeitt! Wow, wow...

Ill have to get around to renting or picking up Monster House sometime. You brought it to my attention a while ago in the 'Waterfall' thread in the dvd section. My dad and I just dont rent those kind of movies. If I get a Blu-ray player and find a copy cheap Id pick it up just for the PCM track.


Its a tough fit on mine...must be a stubborn amp.

Rewatched the pod race in Ep1 last night to check the dif from having one on and then two. Yep, HUGE difference. Also went "old skool" and popped in my DTS Twister dvd. Hmmm, bass sure has gone wild in 10years. Seems shy when you play that after something more modern.

One thing about my thread thats got me odd....

Nobody ever mentions anything about my low-end extension. Just odd. Ive never seen a FR like this before on anyone else other than excessively EQd this or that...IB's and such. This is just two vented 18's with no low-end EQ. Hmmm....jealous? Heheheh. Just kidding.

Bah! AVS Vbulletin wouldnt allow me to add this as an edit for some reason (seriously not trying to over bump this thread at all) :

EDIT: Btw, Ill be updating the FR graph every so often. Making slight tweaks in the EQ. The gash at 28hz can be somewhat filled because it was made a bit deeper cause of my filter @ 25hz. A small bump at 28hz (not boosting a null, shaping the filter) will make it less severe. Dont know if there is much I can do about the 50hz region. Take it as it is. Might sometime try flipping the subs and see what happens but for now, Ill just deal with it. The SQ is pretty damn what Ive wanted out of this whole project. I think that statement speaks for itself.

Yup! Its a very loud movie in all channels. Very good surround sound demo. You nailed the bassiest scenes there, Steve. The opening F5 and the F4 at the drive-in are my usual stops for bass in this movie. The F3 has some moments but they are pretty short bursts of bass. Mostly when they are getting closer and closer or when the tornado picks up the power lines. A good rumble there.


Roflz!!! Ahahahaha! Seriously. Godzilla has more bass in the menu than most of the movie. It has good mid-bass, Ill give it that. Sounded awesome in DTS at the theaters the first day it came out.





Yep, I originally was going for a 12hz tune and went with an 11hz tune in the end. Very wise decision looking at the FR plots at the listening position.


Oh, trust me Steve. You of all people on this forum should know that I knew this looooonnnng before Ilkka posted any measurements.

Hello AVSers!

I wanted to update the Unibox sims for use as reference on this thread if anyone should ever feel that they want to copy the project. Or just in case those out there were curious about how much roomgain has affected the lowend, the amount of airspeed in the vents I could get in such a setup, excursion usage and final impedance.

These are the results of the model...






The point at which the port speed meets the brown line is 11.7hz @ 650w ea. port speed stays under 10m/s >14hz @ 650w

This weeks latest FR from my seat...

Mains on...Xover on mains/LFE @ 60hz.



Much improved!

Oops! Left the "target" (turquoise line) xover @ 80hz on screen....oh well...you get the idea.