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hz numbers on a 15" 2 driver (Read 10744 times)
trashfire
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #50 - 05/02/06 at 17:47:20
 
With Adrian's comment, I can't help but think of the old schoolyard days... "fight fight fight fight!!"  :)  I think if John weren't in CR and I weren't in FL and Bob wasn't wherever he's located, we probably would!  :)

Extending the HWK, aside from looking kind of ghetto, is still going to suffer from the same problem of being a 1 or maybe 2 note wonder.  Increasing the chamber size is going to change the tuning, obviously, but it won't rectify the issue.  

I'm not building the Tuba36 to replace the TT, I'm building it as an experiment and for a different sound system.  Bassboy mentioned it rolling off at 40Hz and down 10db at 20 hz and it keeps going. The vertical baffle is maybe 10db down at 15 hz and not down quite so sharply.  What's not mentioned is the scale.  10db down from 130db is still 120db.  A little EQ will flatten that out very nicely.  

Bassboy, what are the smaller ways to accomplish the response we're talking about?  I'd like to read up on them if you have some links.

Bob, try the extension.  We're all in this to learn and debate (on occasion) our ideas & opinions.  If it works for you, wonderful. That knowledge will help the next guy who comes along with a similar issue.  If not, at least we know, so same deal.  

John, you keep mentioning the TT's size.  It's not really that small. The enclosure is 30X30X16.  That's about the size of a WO or WO32 give or take.  I've got some woofers intended to go into a WO and I will be building one in my quest for the ultimate sub.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #51 - 05/02/06 at 19:06:15
 
John, I was with ya on the construction for awhile there until you said; "the bottom would be an insert instead of a cap", it seems so obvious the bottom plate would be relocated, but since you mentioned it, makes me wonder if I missed something there.  I understand we're talking adding hieght to the enclosure, but are you saying attach the extra wood to the SIDES of the box extending lower? Then I see how the cap plate would fit inside.  What kind of numbers we talking here for extra box length, port length and diameter? WinISD program is at home, I'm not. Wanted to get started on construction in my head. ( besides, like I said, I know just enough about the software program to ruin some wood.  ::) )

I'd almost be willing to build the TT and start my collection of subs to fill the hz/db gaps if needed. I've got an older Sony stereo receiver that does 100wpc I could use. But would rather alter what I've got.

Bob
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« Last Edit: 05/02/06 at 19:53:18 by Bob »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #52 - 05/02/06 at 19:22:20
 
Trashfire,

Now you are just pulling numbers from the air.  Bassboy is probably correct that those predicted responses on Bill's site are with corner loading.  Plus all of the ones I looked at cut off at 20hz.  120db at 15hz, come on get real, 90-95db max at 15hz, maybe.  You really need to talk to Bill instead of just making things up off the top of your head.

There are no links to the kind of stuff you are talking about because it doesn't exist.  Sealed with Linkwitz transform, big vented box, and giant horns are how you get down really low.

While a 6th order bandpass can be a 2 noter, it doesn't have to be.  I built several HWK 12's for friends and they all worked fine with reasonably flat response from 40-100hz.  All I want is the same octave and a half, but starting as close to 10hz as possible.
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trashfire
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #53 - 05/03/06 at 01:29:15
 
Additional charts are provided in the plans and have been discussed in the forums.  The 120db figure is obviously not 1w/1m but what someone measured, not predicted responses.  These figures also do not apply to the TT, I was referencing the T36 if that wasn't clear.  

There's no point to arguing with imagined numbers. It serves no greater good.  Any figures I quote are going to be measured responses.

If all you care about is an octave and a half, BP is right up your alley and I wish you all the enjoyment it can provide you.  Audio is too much a subjective topic to have a right and wrong answer.  I want as many freq's as I can get to sound the same.  That's just me.  

For my purposes, my overcompromised horn is a better performer than the HWK ever could be.  I'm not going to try to shove my beliefs down anyones throat and tell them what they should like.  

My opinion, and it's just that, the best solution is to ditch the HWK and build a horn enclosure.  If that doesn't work due to desires/sunk costs/taste/etc then disregard.  

Unfortunately I do not have the knowledge of bandpass enclosures to offer any advice on modifying the HWK so I don't have anything else positive to contribute.  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #54 - 05/03/06 at 05:30:58
 
Trashfire,

Don't get me wrong.  I firmly believe that horn bass and OB bass are the 2 best sounding ways to make bass.  It's just that neither is practical once you start talking about real HT extension and getting the performance level where you never feel the need to build yet another sub.  If subsonic extension was reasonably achieveable using horn loaded enclosures, then no one would build anything else.

If anything near 120db at 15hz was possible from a 36"x36"x20" single 15" horn or even the 36" cube dual 15" Tuba 36, I'd start building tomorrow.  Just filter or EQ the higher response down to flat and you'd have the ultimate subwoofer for music and HT.  Unfortunately, the laws of physics get in the way.
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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #55 - 05/03/06 at 12:30:42
 
problems solved with this
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« Last Edit: 05/03/06 at 12:40:18 by adi_ro »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #56 - 05/03/06 at 13:35:50
 
Dude, are kiddin' me? I guess that would fix it.  ;D I could fully load a HWK for just over $2,100.   Cry That's friggin' dandy.  :-X

Ok, back to reality...... (Adrian, got a couple grand I can bum?)

JOHN HELP... I "played" with WinISD for 'calculate box dimentions', and it said this version can't perform this task. WTF?!
You got me all worked up and exited now John.

Bob
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« Last Edit: 05/03/06 at 13:36:16 by Bob »  
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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #57 - 05/03/06 at 14:10:25
 
Bob, if i had 1k$ i'd jump on an rl-s 15 and a 2kw pa amp. but i don't have that money.  :D
sure i'd lend you a couple grand.
it's too much xmax (38.5mm) for the hwk. it would blow up  :D
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« Last Edit: 05/03/06 at 14:10:41 by adi_ro »  
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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #58 - 05/03/06 at 14:21:05
 
Bob, you could try to simulate in winisd a vented box and choose the EBS alignment. -3dB version i guess. ebs is a pretty good choice for ht.
another idea would be to look into TLs.
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« Last Edit: 05/03/06 at 14:21:47 by adi_ro »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #59 - 05/03/06 at 14:48:15
 
Well Adrian the thing is, I've got this house wreckin' beast in my room that I'd like to tweek. Sure there's some pretty sexy looking units out there that have more than peaked my interest (grass is always greener) but I was trying to stay monogomous [sp?] if you know what I mean. Would love to have the ability to have several to swap/play with, I've got plenty of space, but it's not possible.

EBS? have heard of it, forgot what it means. Please refresh my memory...

Bob
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« Last Edit: 05/03/06 at 14:49:57 by Bob »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #60 - 05/03/06 at 14:52:36
 
Guys,

Don't get fooled by hype.  That sound splinter thing has the specs of a piece of junk,  primarily Qts .95, Fs 25.5, and SPL 82db.  Plus I'm sure that Xmax is point to point, so the true Xmax is 18mm.  They're pretty and would make nice OB or IB woofers, but that's about it.  Their own graphs show a steep roll off below 30hz even with the 10cuft enclosure.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #61 - 05/03/06 at 14:57:39
 
John are you teasing me?

Bob
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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #62 - 05/03/06 at 15:07:14
 
whoops. john, the rl-s has a Klippel verified xmax of 38.5 mm (one way xmax, so 3inch peak-to-peak). it supposedly broke the measuring device when the guys at tc sounds played with it. qts is that high, because the BL is constant on the whole stroke . on any sub the qts varies across the stroke because bl varies across the stroke. xbl^2 is nothing compared to that when it comes to linearity.
info on the topology used by the rl-s : http://www.soundsolutionsaudio.com/forum/index.php?showtopic=2748
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« Last Edit: 05/03/06 at 15:11:01 by adi_ro »  
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HT-EXT
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #63 - 05/03/06 at 15:43:04
 
Bob do not get rid of the HWK. Just build another sub, of course on a budget, to complete the circus. WO36, WO32, or some of John suggestions that could be located in front of you to play lower bass than the HWK and use the HWK to fill in what you might be missing(50Hz to 100Hz). The klopping noise is the speaker being over driven to the point of bottom out just like the others said. With the amp only turn up a quarter of the way it seems that you gains on the receiver might be set to high. Not that I am the master of adjustment but when I play the movies you talked about with excessive gain on the receiver my HWK15 sounds like the "Budweiser Beer Wagon" pulling up to the front door and loudly I must say(klop/klop/klop). Just my "Brain Wiped" two cents.       HT-EXT
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #64 - 05/03/06 at 15:54:27
 
The "Budweiser Beer Wagon" pulling up to the front door is a good thing.  ;D

Bass setting on receiver is at 50%, less than that make the surrounds sound weak. (NO system eq unit)

Bob
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #65 - 05/03/06 at 16:05:55
 
Bob,
I wouldn't even worry about WinISD, since it won't model the center chamber.  Just go with Dan's dimensions for the big chamber and build it with an extension to your current bottom chamber.  To get it to his size just do the following (You'll need a sheet of plywood plus enough for say 3 or 4 shelf braces similar to your current driver cutout baffles, but only 1 thickness is needed, and a new end cap, same as your current one but the new interior dimension will be the same as your original cab exterior dimension):

Cover the 2 current bottom port holes from the inside.

Cut 4 side panels-  48"x (current exterior width + 1 material thickness).  I go a tad wider, then use a flush bit for the router to perfect the edge after assembly.

Cut 3 or 4 braces-  Original cab exterior width X depth.  Make a big cutout for air flow (driver cutout size should do the trick).

Now if you didn't do wrap around assembly the first time, you get to learn the easy way.  Attach the braces to one panel, flush with one edge.  Then, starting at the non-flush edge, attach the other panels one at a time to the existing panel and braces by wrapping them around the braces.

To make it so you can take it apart and get to the bottom driver but get a good seal, build a sealing ring on the interior of the new construction 4" from one end.  Say four 1" peices of material forming a ring around the interior, 4" from the end.  Using foam rubber as a gasket on that ring, it will give you a seal when you slide the end of the original cab into the new construction and attach it with screws.

Build your end cap the same way as the original.  I'd put the port in the end for simplicity and go with a temporary straight port at first and try a few different sizes for desired tuning, starting with Dan's recommended 4" by 17".  You'll probably settle on something a little shorter (higher tuning), since the other end is tuned a little higher than Dan recommended.  Once you get the tuning you want, buy flares for both ends.  I'd replace the coffee can port with a real flared port too, unless it has zero port noise.

That should give you impressive extension, eliminate the whacking noise, and make you feel like you're inside the fish tank when Darla taps on it in Finding Nemo.  If you still have some excursion problems at very low frequencies, then you'll need to tune coffee can port lower with a longer port.  Your current banging problem is most likely with your current bottom driver and chamber, not the top, so the new big chamber should resolve it.


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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #66 - 05/03/06 at 16:59:40
 
John, your cool, and Thank You. Helluva detailed description.
I buzzed through quickly once, will read it more methodically later today.

But a couple questions I noticed;
-We are talking a structure that's 7' 8" correct?
-Leave driver location alone
-I installed 1/2" fiber padding in top and bottom chamber. Should I; Leave it alone, / add more to extension, / or take it out stupid, it shouldn't be there in the first place (noticed no difference anyway).

Thanks again John,
Bob
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« Last Edit: 05/03/06 at 17:00:21 by Bob »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #67 - 05/03/06 at 19:22:51
 
Bob,

You got the idea, but I think more exactly 7' 10.25" with top and bottom caps and using the current bottom cap as a brace and cutting a big hole for air flow.  You have room to lay it on it's side right?

I wouldn't even take the drivers out or disconnect them.

Maybe save the padding for another project, or leave it there.

We haven't talked about your mains.  Do they go low enough to work with a sub that only goes up to 40-50hz ?
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« Last Edit: 05/03/06 at 21:39:43 by JohnF »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #68 - 05/04/06 at 18:57:43
 
Yes, I've got 11' in width behind the seating.

No John those mains won't do that.   Sad Angry  I'll have to tolorate the gap until I can find something to build.
Looking for plans for a center, and four surrounds.  ;D   I had a long conversation with Dave (hurdy) and Terry about driver numbers. I havn't got "the right stuff". Not even close. (I don't mind learning by my mistakes, just when those mistakes cost $, that's when it's harder to swallow.

....Got any plans in your back pocket?

Bob
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #69 - 05/04/06 at 20:45:08
 
82 dB sensitivity on the RL-S sucks hard.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #70 - 05/04/06 at 20:47:05
 
Thanks 'J', you just made me feel soooo much better about my 89db........ Cheesy

Bob
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #71 - 05/04/06 at 20:51:01
 
Well, considering your 89 dB will get as loud with 300 watts, you should feel proud. lol.

I mean, full wattage the RL-S thing will ony go to 122 db. (without the box in the equation....)
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« Last Edit: 05/04/06 at 20:51:54 by j_rock777 »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #72 - 05/04/06 at 21:10:02
 
Bob,

I would say let's change the plan to one of my backups, in case the HWKenstein didn't work for you.  You can even use the same construction outlined above giving you the flexibility to try both with the only waste being 2 end caps.  

That plan is to create 2 low tuned ported subs using the old HWK as one box with the driver on one end and the port on the other.  The new construction would be the other sub.  Put them both behind you firing at each other and the ports firing into the corners resulting in some extra down low.  That way you'll get the top end extension to meet your current mains and still get great extension at the bottom end.  You won't have quite the max output down low as the bandpass, but I'm pretty sure it will put a smile on your face, especially since you have 2 of those Dayton 15's.  It will be close to EBS (Extended Bass Shelf) tuning.

If you construct and connect your end cap/drive baffles in the same manner as the HWK end caps, then you will be able to try both ways.  The ported boxes will work better for music because you can stuff the ports for music and open them up for HT.
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« Last Edit: 05/04/06 at 21:12:05 by JohnF »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #73 - 05/04/06 at 22:44:50
 
Ok, John let me make sure I've got this correct.

-Build your idea as planned.

-Don't "SEAL" the double ports permenantly on the old HWK.

-You said; "Put them both behind you firing at each other and the ports firing into the corners resulting in some extra down low." --- You lost me there. "AT each other, but ports AWAY from each other?"

-Does the new box have the 3 ports just like Steves, or eliminate the doubles in the second build? The single center port would be 4" X about 17"?

I've modded this reply seven or eight times, got frustrated, removed it once, and started over.  >:(  Just when I think I've got it straight, and only have a couple questions .....  :o ? bla bla bla.


I THINK I'm with you John

Bob
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« Last Edit: 05/04/06 at 22:45:46 by Bob »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #74 - 05/04/06 at 22:49:21
 
One driver in each box mounted with magnet in lower chamber, so "top" chamber now includes the center chamber also?

Continue running amp bridged with a "Y" in cable?
Or, run each sub on it's own channel? It might have some kind of neat stereo thing, or it might just sound funky running it that way.

Bob
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« Last Edit: 05/04/06 at 22:58:25 by Bob »  
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #75 - 05/04/06 at 23:56:45
 
[quote author=Bob  link=1145573673/75#75 date=1146779361]One driver in each box mounted with magnet in lower chamber, so "top" chamber now includes the center chamber also?

Continue running amp bridged with a "Y" in cable?
Or, run each sub on it's own channel? It might have some kind of neat stereo thing, or it might just sound funky running it that way.

Bob [/quote]

No, each box would have the driver mounted on one end and a port on the other end, no more chambers.  You'd just be able to easily convert it to the HWKenstein later.

Another alternative is to build HWKenstein exactly as described and leave the cap off of the original cab.  Give me a few days to crunch some numbers first and get port lengths for your different options and do some modelling to be sure they all make sense.  Plus I have another idea that I need to model first, and it might involve even less construction.

The bottom line is that you don't need different drivers or amp and you can put what you already constructed to good use.  At most all you need is some wood and port(s) and end up with impressive bass.  

Sometimes I forget and talk about what I would build for myself.  I already have plenty of subs to choose from and most have much more output than sane people would want.  I'm into this mode now where I want to outdo Dirt Dawg's Big Whistles and make my chair move with big LFE's.
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #76 - 05/05/06 at 00:50:49
 
OK Bob,

Here's something easy to try this weekend.

Take the bottom and top caps off of your HWK.  

Take the bottom driver out and clamshell it with the top driver.  Wiring remains the same (opposite for each driver since they are still push/pull).

If you don't already have a 4" port, pick up a 13" piece of 4" PVC.

Block one of the bottom ports from the inside with a piece of wood.

Enlarge the other bottom port just so the PVC fits snugly from the outside (enlarge it to the top and center of the cab so you don't interfere with the bottom cap and try not to mess up your exterior finish work too much).  This is just a test for you at first, so let the port stick outside the box.  The tuning difference will be insignificant.

Try to smooth the interior and the exterior ends of the port as much as possible.  Don't worry too much because without flares on both ends, you'll probably get port noise due to turbulence no matter what you do even though that interior corner will act kind of like a flair.  Remember this is just a test, so ignore port noise.

Put the bottom cap on (leave the top cap off) and crank it up.

You now have a ported sub with a Vb (interior net volume) of right at 150L, with a port tuned to 19hz (actually a little lower due to port placement).  You should have a gradual slope from 50hz down to -3db at 19hz and a -10db at 14hz, which should be offset by room gain unless you have an open room configuration, so a net in room close to flat down into the teens.

The exposed basket of the driver on top will be hidden by the old top chamber.  That open chamber will have no effect on response at these subwoofer frequencies.  You will have traded some amp power for a smaller box and your max output is 6db less than possible with the same total power and 4 times the Vb.

Let me know if that does it for you and I'll help you finalize it when I get back from the beach Monday.  Gotta get back to burning CD's to bring with me to listen on Silver Iris OB-RLH's down at the beach.



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Bob
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Re: hz numbers on a 15" 2 driver
Reply #77 - 05/05/06 at 11:56:36
 
Thanks John... "Gotta get back to burning CD's to bring with me to listen on Silver Iris OB-RLH's down at the beach."

Don't work too hard.  :)

Goal #1 this weekend, build a deck. (WAF ya' know....)
#2 tweek sub. (my play time  :()

I'm sure I can find a reason to "need" to go to Home Depot to get one more nail for the deck. A couple pieces of MDF and a lenth of 4" PVC may happen to fall into my truck, 'How'd that happen?'  (just in case HWK needs steroids. Can ALLWAYS use MDF.)

Thanks again, John

Bob

p.s.  John said, "I already have plenty of subs to choose from and most have much more output than sane people would want.  I'm into this mode now where I want to outdo Dirt Dawg's Big Whistles and make my chair move with big LFE's."

This is a good thing!

Hey BTW John, how do you keep your projector bulb from exploding with the LFE's?
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« Last Edit: 05/05/06 at 12:02:55 by Bob »  
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #78 - 05/10/06 at 13:07:40
 
John, I bought "Master and Commander" based on Rap's recommendation a couple months ago. Very good movie. Was anxious to hear the LFE's.....My God man!   I had to keep turning down the amp, AND reciever to keep Mr. Klop at bay. I see the potential of the LFE, but frustrated that I can't "get there from here".

I think I've got myself another LFE referance movie....

One thing I'll say about the Daytons, they must've been made by Timex, 'cause they take a lickin' and keep on tickin'.

Bob
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gexter
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #79 - 05/11/06 at 01:07:39
 
Thats the movie we were seeing how much the big pair of SV subs could handle. we had to remove the wall lamps and stuff off the walls even before we turned the sunfire power subs loose.
felt like the carpet was rippling under our feet.
too bad it was my cousins system. Well maybe a good thing because my wife got pretty cranky during a couple cannon shots.
she was on the deck outside and I got a earful when we left.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #80 - 05/11/06 at 11:57:19
 
Hmmm Gex, I really hope it rains this weekend. Why you ask? Well you can't build a deck in the rain, BUT, you CAN tweek a sub!  
I'm looking forward to performing John's HWKenstien "adjustments" to the sub. I'm definetly missing something here in the LFE realm. In NO WAY am I rippling carpet much less 'wrecking the house'.

Bob
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gexter
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Re: hz numbers on a 15" 2 driver
Reply #81 - 05/11/06 at 13:08:36
 
LOL
Bob I am very interested in Johns mods as much as you, and rain is good news for both of us.
If you were closer I would  help ya so you could get to your sub. I like building decks Smiley No really!
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #82 - 05/11/06 at 13:22:37
 
I'm not that far away from you, well,... compared to John that is.  ::)

I like building decks too, just not when I'd rather be in my cave.  :'(

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #83 - 05/11/06 at 19:09:12
 
Try the simple one first.  It may be enough.  You can't beat that size, but port noise is my concern as an ultimate solution.  Plus, you can squeeze in doing the new bottom port while she goes to the store.  Then after dark (can't build pretty decks in the dark), you can swap the driver over to the top and be testing Master&Commander that night.  The HWKenstein won't work with your current mains anyway and the single isobarik BR may be enough for now.  That way you'll have a better idea of what you ultimately want (more extension, more max output, etc).  Plus you can start tracking down your room rattles and get wifey used to the concept of high impact LFE's.

Oh, I almost forgot.  Stop banging that back plate on your drivers.  You have some good drivers and you don't want to mess them up.
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« Last Edit: 05/11/06 at 19:15:00 by JohnF »  
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #84 - 05/11/06 at 19:57:50
 
Hi John, Port noise seems easily remedied by "creative flaring", I would think?

Forecast for St. Louis is RAIN 'TIL MONDAY,... WOO HOO.

As far as what I ultimately want,.... subsonic, no driver self destruction, good quality sound (doesn't have to be perfect. Remember it's not an audiophile listening room)

The mains John, are on "the cut list". They'll be going soon. I'd like to chat about those someday, as far as DIY options go. Just not in great detail at this point. --- Baby steps. Smiley

Wifey is getting "used to" overall volume capabilities of the overall system, but hasn't (obviously) had much in the way of LFE potential.  :-*

I get this panicy chill in my spine when I hear that noise. Scrambling for the correct remote in a pile of 6 in the dark to turn down the volume is getting old. (LFE is done and gone by the time the I.F. hits the eye anyway  >:()

I'm sure I'll be in the cave this weekend, a cuttin'. Shouldn't have a problem getting mods finished. I still can't post at home  ::) so I'll be getting back with results on Monday.

Hey, by the way, Just for grins / in the name of science.... Those Radio Shack SPL meters are pretty cheap arn't they ($35?)  Would it be worth the time/$ to get an A/B difference as far as max (unbottomed) output goes? What do you think?

Bob
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gexter
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Re: hz numbers on a 15" 2 driver
Reply #85 - 05/11/06 at 20:45:52
 
Get one. well worth the money.
I have to sneak a replacement into the house for my old one.
great for balancing HT I use it at first then by ears
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #86 - 05/11/06 at 20:48:07
 
Nothing like that is cheap down here.  Once I finally found an SPL meter, it was over $150.  While you are at Radio Shack, put up a programmable remote.  Once you get it going then you have just 1 that controls everything.  It's worth every penny and time spent setting it up.  Generally you just need on/off for the PJ, on/off + volume for the receiver, on/off + guide + chan(+/-) + prev chan for DirecTV and cable boxes.  I tried to put all functions of everything in mine, but ran out of memory, however, doing so gives you backup in case you lose a remote.  I still don't understand how some things on some units can't be done without a remote.  eg I can't even turn on my video enhancer unit, which centralizes all of my video sources, without a remote control.  That's just absurd, but I have backup now and remotes all go in one secure box if I need them.

Re port noise, big 2" radius flares help tremendously, but eg with the HWKenstein that's a lot of air to push through a longish 4" port and you may get a high enough velocity in the port that turbulence is inevitable.  With HT, a little port noise doesn't matter because there's plenty of other noise happening along with those LFE's that you don't hear it.  Plus you have your PJ noise to overcome already.  You'd have to be an organ music buff for it to be bothersome.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #87 - 05/11/06 at 22:51:39
 
PJ noise is VERY tolerable. Almost not even there!  :)

You may have missed an earlier question I had John, Do you do anything special to isolate the PJ from the LFE?
I'm already getting a slight amount of "jitter" on the screen from the HWK during 'Darla and the cannons'. (worried about bulb failure)

Why is the meter so expensive there, is it the cost of the equipment, or shipping? If it's the cost of the item, let me know if I can ship you something?

A buddy has a Sony 'Commander' he lent me. It won't control the Sanyo PJ for some reason. I got frustrated and put it down a month ago or so. I'll pick it back up one of these days.

Bob
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« Last Edit: 05/11/06 at 22:52:18 by Bob »  
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #88 - 05/12/06 at 00:04:19
 
Bob,

My homemade PJ mount is connected to one of support columns of a concrete wall, so only earthquakes can make it wiggle.  I don't think the LFE's will directly impact the bulb, but I agree that if what they are mounted to vibrates a lot it can't be good for the bulb at operating temperature.  Test it using a slow tone sweep with the PJ off first just to be sure you aren't stimulating a resonance in whatever supports the PJ.  You need to do that anyway to tie down room rattles.

Re the SPL meter, I needed it that week, plus my M/C doesn't work online, so the timing and cost didn't justify having someone buy it stateside and ship it to me.  Hard to find stuff can have silly prices, but our full time maid/nanny is only $200/mo and my skilled builder/helper is extremely happy with $20/day, so I don't complain, especially with shorts and tshirt weather year round and no A/C or heat needed.  Where I live it's lows of 60-70 at night and highs of maybe 80, year-round.  The sun can be brutal, but in the shade is always pleasant with a breeze.  I die down at sea level at the beach though.

I just use the top end Radio Shack remote, the one you can just point another remote at and copy the controls you want.  Quick and simple.
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« Last Edit: 05/12/06 at 00:06:42 by JohnF »  
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morpheous85
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Re: hz numbers on a 15" 2 driver
Reply #89 - 05/12/06 at 16:37:11
 
[quote author=Bob  link=1145573673/75#88 date=1147384299]PJ noise is VERY tolerable. Almost not even there!  :)
[/quote]

Ok, what is PJ noise?

Jason
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #90 - 05/12/06 at 16:43:16
 
Video morpheous,
Front screen projector (PJ). Cooling fan internal in the unit can be loud in some units. Projectors are usually located above and behind the seating position.

This is my rig. Notice the PJ tangling from the ceiling...

http://community.webshots.com/myphotos?action=showPhoto&albumID=549522535&photoI...

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #91 - 05/12/06 at 18:03:03
 
Bob,

Shorten that mounting pipe for the projector, which will reduce the wiggles tremendously, or do you have a beam between the PJ and screen like I do which requires a low mount?  If nothing is in the way then getting it up high will have other benefits;  less shooting in the eyes, less heads blocking the image when someone gets up, brighter image because more light reflects down to the viewing area, brighter image because less light reflecting to the ceiling, less chance of someone bumping into the PJ, and best of all, a better picture because you'd use less keystone correction, which distorts the image somewhat.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #92 - 05/12/06 at 18:35:42
 
Yea, I've got "the beam" in the way.  >:(

Actually keystone is almost dead-on. It puts the lens VERY close to the vertical AND horizontal 1/2 way point of the screen.  ;D

Current location is as far BACK from the screen as I can get. Any closer to the screen, and the PJ will be directly over seating position. (don't want to smack it when I have one of those late-night over the head arm stretches, ya know.)

Here is a picture of the room with the "beam" (lower ceiling).... the "coffered" ceiling is drywall and is flanked by acustical tiles above and behind the seating position (shown in pic), and the same square footage of tiles is also in front of the screen. THAT area is several inches higher than the tiles you see in this pic. The reason was to get the screen higher off the ground. The reason for the lowered section of drywall, where the recessed lighting is, is the beams that hold up the house are inside the "coffer". (don't know how to spell that)

http://community.webshots.com/myphotos?action=showPhoto&albumID=549522535&photoI...

If you look in the far upper left corner of the picture, you can barely see the first ceiling tile. Notice it's higher than the tiles in the 'back' of the room.

Bob
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« Last Edit: 05/12/06 at 18:38:11 by Bob »  
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morpheous85
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Re: hz numbers on a 15" 2 driver
Reply #93 - 05/12/06 at 18:35:50
 
Ahh...it now makes sense. Thanks.

What about movie theater style where it's in a seperate room, shining through plexiglass or glass? Or, just build a plexiglass box around it (with ventilation of course).

Jason
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #94 - 05/12/06 at 19:16:48
 
morpheous, In another room would be a great idea, shining through glass. (logistics might be a bit of a challange, what to do in the other room to hide AND ventilate the rear of the PJ). Minimal video loss beaming through the glass, but probably acceptable.

Building a plexy box around it wouldn't be a good idea. The amount of holes drilled in it to get the needed airflow,... you'd end up hearing it anyway. Some guys have built "hush boxes" around the PJ. Simply a box with sound insulating lining, and an auxillary fan. But then the fan needs to be quieted also. Kind of an endless chain/dominoe effect if you ask me. PJ manufacturers are good about stating db output from fan noise, so you can be selective about the unit you buy. If it's going in another room, you have many more options on projectors to chose from since db's don't matter, see.

Now we're speaking my language. (feeling more confident talking about video than audio)  :D

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #95 - 05/12/06 at 19:43:53
 
Shooting through a piece of glass will eat 6% of the light output and Bob is already giving up a lot more than that with the see-thru screen (I see your speakers now on the screen only pic).

Bob,
You can probably pick up some stability by bracing those supports up above the ceiling tile and maybe a glass right triangle brace on each of the 2 front supports.  It all looks kind of wiggley.  Paint the supports all the same color at your walls for the PJ floating in the air look (at least the pair in the front).

BTW, work was done early last night, so we watched Finding Nemo with the kids.  We did the Darla scene a few times and just running  a single 100L ported 12" Shiva that is tuned to 24hz, we were getting quite a nice effect and that's probably -12db or more in the teens where the tapping really hits.  It was enough to get a little eyeball jiggling, but not the strange chest compression like in a car.  

I really think the iso loaded Dayton 15's in the box you already have and the single port making it a low tuned BR should hold you over until you're ready to get radical.  Plus the finish work is already done.  A tube for a port, bolts to clamshell the drivers, a small piece of wood to block the 2nd port, and something to seal is all you need.  Worry about HWKenstein later.
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« Last Edit: 05/12/06 at 19:45:47 by JohnF »  
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #96 - 05/12/06 at 21:09:43
 
John, The 3 speaker hole silouettes you see are no longer. Of the original 7.1 set-up, you obviously see the 2 front main surround. The system is now 5.1. The side surrounds are now the fronts. I had very little channel seperation with the fronts 9' apart, sitting about 17' feet back. Speakers behind cloth, well.... you guys don't need any more explanation there. Now the fronts are 12' apart, and 5' in front of the seating "plane". MAN, talk about stereo/surround seperation. 100% better.
The center is now sitting on top of a stand 1/2" below the bottom of the screen. Originally I wanted a 'clean' look, hiding 3 speakers would be idea,  but didn't stay that way for long.

I like the glass triangle idea John. Also may use extensive rubber for the feet of the PJ.

Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #97 - 05/12/06 at 22:28:26
 
The center could go behind the screen.  Just turn the volume up for it to match.  You can also mount the PJ upside down, which can shorten the mount length by 4" and make it that much more stable.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #98 - 05/12/06 at 22:52:50
 
As far as the center behind the screen goes, if it's not 'right' then I'd rather not do it. Without spending a bunch on "acustically transparent" screen material, I've not found a way to get enough 'regular' material in the cut out to adequitly [sp] hide the fact there's a hole there without severely muffling the drivers. I've played with center channel volume but in the end it just sounds like a pillow over a speaker, just louder. For the throw distance and screen size I've got, I really need a screen material with about a 1.5 increase in gain.

Don't think flipping the PJ upside down will give anymore vertical hieght. The lens is placed directly in the center (top to bottom).

Well, gotta go, 6:00pm Friday night. Leaving work. Chat with ya' Monday.  ;)

Bob

p.s. weather may be clearing for the weekend.  :( Angry Sad Angry
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #99 - 05/12/06 at 23:35:32
 
[quote author=Bob  link=1145573673/90#99 date=1147470770]Don't think flipping the PJ upside down will give anymore vertical hieght. The lens is placed directly in the center (top to bottom). [/quote]

You did need the weekend.  You mount the PJ to the bottom of that platform and shorten the supports for same overall height of lense, but shorter supports will be more stable.

BTW,  It's good to get away from the speakers behind the screen.

With a new screen, if you can lower the top of it, then you can raise the projector.

I want to see smileys on Monday.  Do that conversion on your HWK this weekend.
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