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16 x 18's in a 1500ft^3 Space - Popalock's Sub Build - Page 25

post #721 of 943
Quote:
Originally Posted by desertdome View Post

For the Star Wars themed theater:



Hahaha, he's "hung like a light switch."
post #722 of 943
Quote:
Originally Posted by Suntan View Post

Only downside being that they tend to stick out a fair bit. Especially if you have thick speaker wires.

-Suntan

Also a little bit of a recess helps, especially in conjunction with the 90 degree plugs. From a project I finalized last Friday:

post #723 of 943
Thread Starter 
Quote:
Originally Posted by Gorilla83 View Post

Also a little bit of a recess helps, especially in conjunction with the 90 degree plugs. From a project I finalized last Friday:

Niiice! I checked my boxes again this afternoon and this time noted that the banana plugs worked loose on the boxes as well. I foresee some box updates in my near future for sure!
post #724 of 943
Quote:
Originally Posted by desertdome View Post

For the Star Wars themed theater:


Lol man I love that!
post #725 of 943
Sup Austin! Just curious since you owned the LMS ultras, did you hear a difference in sound quality going with the SI18s? I know the ultras are touted for their low distortion and am curious if multiple 18s using less excursion level the playing field. I have 8 SIs now with 2 FTW 21S coming soon. I'm not strained now just wondering from your point of reference.
post #726 of 943
Thread Starter 
Quote:
Originally Posted by gpmbc View Post

Sup Austin! Just curious since you owned the LMS ultras, did you hear a difference in sound quality going with the SI18s? I know the ultras are touted for their low distortion and am curious if multiple 18s using less excursion level the playing field. I have 8 SIs now with 2 FTW 21S coming soon. I'm not strained now just wondering from your point of reference.

Good question. I hate to sound like Mr. "Politically Correct," but I find it very hard to quantify a difference in sound quality.

One thing I can tell you right up front is that I found it much easier to get the LMS-U's to exhibit the "type" of sound that I wanted from them. As you (and I'm sure a lot of other people) know by now, I am extremely bias to the ULF end of the spectrum. I found that the LMS-U's provided much more low-end grunt without really having to manipulate the $hit out of the signal.

I was able to get the same result from my SI's, but in addition to boosting the bottom end, I literally had to cut the mid-bass drastically in order to get the same effect I was getting from my LMS-U's. To put it in layman's terms, the LMS-U's seemed as though I had two guys that could bench 600lbs helping me move furniture. The SI's seem more like having 16 guys that can bench 200lbs...lol

I'll be 100% honest...I if I tried to get very technical, I would probably end up mis-speaking or giving you bogus information. With that said and from what I have learned on the forums thus far, I want to say that (in addition to a few other design elements) the motor force (i.e. bl & bl Curve) plays some part what sets a driver like the Ultra apart from a driver like the SI.

I'm basing that off of a post I read from Scott awhile back... Can't seem to find the reference though? Maybe Scott, Bosso, LTD, Beast Ricci or some other technical guru can chime in to shed a bit more light on motor force and how it effects the SI and LMS-U drivers respectively?

As you already noted, with so many drivers on tap we have the ability to keep excursion low and still maintain gobs of headroom. I firmly believe that the SI's can (and do) sound just as good as my Ultra's did at moderate play back levels. Even on a one-to-one basis.

I think something like this would be an interesting experiment:

- Level match one LMS-U to one of the SI-18's
- Use the mini-DSP to manipulate the curve to match response as identical as possible.
- Keep xmax under some arbitrary number where THD doesn't become relevant (say 15mm).
- Compare blindly to see if anyone could tell a difference.

I would put my money where my mouth is and say that no one would be able to tell a difference in a blind comparison. One other thing I want to mention since I touched on the topic of THD. I notice when I have 8 or 16 of my subs rocking, I am picking up vibrations from literally EVERYTHING in and around my theater. Here is a list of what I have found contributing to the noise and (at some point in time) attributed to me thinking that my gear was making some nasty sounds.

Top 5 culprits of nasty sound in my room:

5. Light fixtures. Seem to resonate around 32Hz and again somewhere around 7kHz.
4. Rear Box Vibration. The boxes are unsecure, so in ULF scenes the box rocks back and forth and slams into my rear wall. Very annoying.
3. Mains stacked on top of front boxes. My mains weigh 88lbs and they settle into the duratex finish. When a ULF scene hits, it will unsettle the boxes. Every time it does so, it makes a very loud cracking sound.
2. Bathroom door. If I keep it closed, it is very very obnoxious.
1. Theater seats. When I first engaged my near field subs, it sounded like I was having some serious distortion issues! I did some investigating during intense playback and it turns out that the leather was flapping against the seat frame at almost all frequencies. I'm pretty much at a loss for how to deal with this issue...lol If you ever come to my house for a demo and hear farting sounds on occasion, it's my seats man! In fact, I moved my seats to the middle of the room (about 6ft away from the rear boxes) and this no longer was an issue.

The LMS-U's always sounded smooth because there was much less room interaction. Sorry I can't give you a simple "yes" or "no" answer, but I hope this helps my friend.
post #727 of 943
some sort of vibration pad should keep your mains from bounching on the subs. i can bring you some rubber & cork ones when i come down if you wanna test them out
light fixtures can be braced with foam

as for your seats i would guess some internal support to make the distance any 1 piece of leather has to span will cut down on it flapping back and forth. or you can just staple it like mad to the frame
could also go with some dbl sided tape to keep it from moving. assuming it doesnt need to move for some other reason
post #728 of 943
Austin, very in depth response makes sense. Thx bud!
post #729 of 943
popa, what you are describing is the difference in the bl curve, just as you surmised.

the ultra has a very flat bl curve, so when run to low notes where excursion is high, the driver remains in more or less full force mode.
this is because it has extra windings toward the ends of the voice coil, so as the coil moves out of the magnetic gap on one side, extra coil is moving in from the other side.

the si18ht is more typical and has a rounded bl curve, so when to low notes where excursion is high, the driver loses some of its grunt.
it is typical of a standard voice coil which loses force as the coil moves further away from the center of the gap.
post #730 of 943
here is the klippel of the si along with my hand drawn made up ultra bl curve in red, just to give some idea of the difference.

post #731 of 943
Thx LT that helps put things in laymen terms.
post #732 of 943
I'm liking all this plain english talk, so much less brain-taxing than the modelling and physics terms tongue.gif lol


LTD - going from your curves on that graph (and accepting the LMS is not the measured curve wink.gif) would it be fair to say that the SIs are harder to bottom than the LMS because BL drops off as the driver reaches the end of its excursion?
post #733 of 943
Thread Starter 
Quote:
Originally Posted by MemX View Post

I'm liking all this plain english talk, so much less brain-taxing than the modelling and physics terms tongue.gif lol


LTD - going from your curves on that graph (and accepting the LMS is not the measured curve wink.gif) would it be fair to say that the SIs are harder to bottom than the LMS because BL drops off as the driver reaches the end of its excursion?

I would venture to say that as the bl drops, the cone exhibits less control. That's just my assumption at this moment with no other technical references at my finger tips to research.
post #734 of 943
Ah yes, that would make sense in my head... smile.gif
post #735 of 943
"I would venture to say that as the bl drops, the cone exhibits less control. That's just my assumption at this moment with no other technical references at my finger tips to research."

that's right. in addition to that, the suspension will also tend to get much stiffer the further from the center position that the cone is. together, those make for less control/damping.
post #736 of 943
"would it be fair to say that the SIs are harder to bottom than the LMS because BL drops off as the driver reaches the end of its excursion?"

that cannot be known from the bl graph. drivers can soft bottom or hard bottom depending on a variety of factors. i think josh noted that the lms if given enough juice will hard bottom, but i'm not 100% on that and i don't recall for the si. perhaps, josh has the information on data-bass.com in the driver test area.
post #737 of 943
Quote:
Originally Posted by popalock View Post

Good question.


I'm basing that off of a post I read from Scott awhile back... Can't seem to find the reference though? Maybe Scott, Bosso, LTD, Beast Ricci or some other technical guru can chime in to shed a bit more light on motor force and how it effects the SI and LMS-U drivers respectively?

I found the post.
Quote:
Originally Posted by Scott Simonian View Post

Ah. I was waiting for someone to point this out. You aren't the first person to say something just like this (but compared to another driver than the SI).

You know what this is atributed to? One really powerful motor coupled with the LMS technology on the coil.

Down low in a sealed subwoofer, you are guaranteed to be using a good amount of excursion if not all of it with peaks or overall loudness, most notably in the deeper bass <30-40hz. Some of you have seen pictures of the BL curve of a particular subwoofer driver. In most cases like the SI which is an overhung motor topology you will get a bell shaped curve that follows the excursion. The most amount of motor force (BL in general) will be around Xmax 0 or in a sitting position or within sitting position. As the excursion expands futher more and more of the coil is leaving the gap where the most flux in the motor is and the force from the motor/coil combination starts to drop. In some ways this can be an alright thing because that loss in force can possibly protect a driver from damaging itself by overexerting. Some might remember a year or so back and people were damaging their LMS-U's with too much power. The LMS-U has just as much motor strength at Xmax as it does just sitting.

Coming back from that I think this is why users that own LMS-U's and compare them to others say things like you did (where I quoted). There is plenty of power during the full stroke. Producing deep bass at any volume is forceful to put it one way. Using lesser drivers can somewhat compete with multiples but I think only within a margin of total output and that scales with how many drivers we are talking about.

John did a pretty good job in this thread. Thanks!
post #738 of 943
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

"would it be fair to say that the SIs are harder to bottom than the LMS because BL drops off as the driver reaches the end of its excursion?"

that cannot be known from the bl graph. drivers can soft bottom or hard bottom depending on a variety of factors. i think josh noted that the lms if given enough juice will hard bottom, but i'm not 100% on that and i don't recall for the si. perhaps, josh has the information on data-bass.com in the driver test area.

Yeah, I'd say this qualifies as a "hard bottom."

ce81f3a7.jpg

Reference post here.

Quote:
Originally Posted by Scott Simonian View Post

I found the post.
John did a pretty good job in this thread. Thanks!

Thanks for digging that up Scott!
post #739 of 943
Thread Starter 
Well gents...

I finally got around to framing out my AT screen last night.

IMG_20130905_043409_zpsa2dce131.jpg

I was able to get everything in place early this morning to snap a photo with the only camera I had available. Sorry for the horrible PQ. I still have to fabricate a few panels to give it a finished look, but I don't think I will have time to do so for the next few weeks. I like the result thus far. It's going to be nice to finally test out the AT screen!

I'll hopefully be able to snap a few better photos this evening and post them up.
post #740 of 943
Looking good my man! Have you thought about running the center vertically? I suppose you were targeting alignment of all the horns but might be worth experimenting.
post #741 of 943
Thread Starter 
Quote:
Originally Posted by Gorilla83 View Post

Looking good my man! Have you thought about running the center vertically? I suppose you were targeting alignment of all the horns but might be worth experimenting.

Yeah. I thought about it, but wouldn't that make the sound come out sideways?

I'll play with it over the coming weeks. Maybe I'll end up being a sideways sound pioneer...
post #742 of 943
are the horns uniformly shaped in the klipsch? if so it wont matter. if yes you would simply need to rotate it 90 degress to fix the sideways issue
post #743 of 943
I like! It's probably gonna end up looking close to mine except mine are dual opposed.
post #744 of 943
Quote:
Originally Posted by gpmbc View Post

I like! It's probably gonna end up looking close to mine except mine are dual opposed.

How does your response do with the drivers being nice and close together like that dude? I was talking with Austin last night about possibly even designing a box where all four drivers are basically aiming at each other in a square manifold in the dead center of a huge box. almost like a square doughnut type look. It would put all the drivers very close together and probably make the midbass area more efficient and time alignment I feel like would be perfect doing it this way over spreading subs all around the room.
post #745 of 943
Thread Starter 
Quote:
Originally Posted by Sibuna View Post

are the horns uniformly shaped in the klipsch? if so it wont matter. if yes you would simply need to rotate it 90 degress to fix the sideways issue

C'mon man... "Sideways Sound?" You know I was kidding!

The center has a 60x90 dispersion pattern. Rotating it wi just give a 90x60 pattern. Might potentially cause more of a reflection issue from my ceiling, but I since I sit fairly close, I'm not anticipating and real issues.
Edited by popalock - 9/5/13 at 7:52am
post #746 of 943
i know you were being sarcastic, so was i
post #747 of 943
LMAO, maybe that has been my problem all along...sideways sound ftw.
post #748 of 943
Thread Starter 
Quote:
Originally Posted by Sibuna View Post

i know you were being sarcastic, so was i

Dammit! You got me...lol.
post #749 of 943
Naked
After XT32
post #750 of 943
I have had better curves from various runs of Audyssey but those are what I had off hand.
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