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hz numbers on a 15" 2 driver (Read 22721 times)
Bob
Ex Member



hz numbers on a 15" 2 driver
04/20/06 at 22:54:33
 
I've had the housewrecker for about 3 months now, getting a good feel for it (meaning; doesn't seem as impressive as it used to.) For HT use it just doesn't seem enough, and turning the knob up just creates the horrible 'klopping' sound from drivers hitting mechanical limit. Currently using 900 watts bridged to two Dayton series II 15" drivers, magnets mounted in center chamber. Seems like these are 'accepted' drivers for this use. Has anybody got any hz or db numbers on a set up such as this? Has anyone found a different mounting arrangement achive better results for 2 drivers? I'd rather spent time/effort on my surrounds, as opposed to putting two more drivers in the enclosure, but is that what it's going to take? As a few of you know by the pictures, they won't be easy to take the existing drivers out, or rearrange. So 'playing' with it just to put them back would be aggravating. Adding won't be a problem, just $$$ not spent on surround drivers.

Any assistance is greatly appreciated.

Thanks guys,  Bob

BTW, Have moved it around the room many times (lower back hurts) I made a base that it sits on (big hole facing down) much like the sono tube arrangements with 5" of air space between it and floor.  The twin holes are firing perpendicular, behind and right of the seating position. (pics can be seen on "amp to make Daytons happy" thread page 12, reply #171.)
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« Last Edit: 04/20/06 at 23:01:07 by Bob »  
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gexter
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #1 - 04/21/06 at 13:12:02
 
I can't take the time to go back over stuff and see where your at or look at the pics right now.

But...
Changing the driver arrragement for a sure change is a complete unknown. from reading I think it depends on the characteristics of the driver to the enclosure.

I do think that your best choice is changing one of the ports. smaller and longer on the top maybe? It can't change too much because of the driver. Thats only a guess and I have not done it.

My best guess is there is not enough damping and the driver looses control. a short Xmax and good damping characteristics on the driver may go a long way.
a port change may do it, but it will change the freq.
I have thought about additional baffles in the box but never tried it.

Really Man I am just guessing from an experimenters frame of mind. No science there!
It would be the last Decware design that I would build another of at the moment..
I just finished my second DB12 and it works better than my last and restored more faith in the DB design. I still have to wait until my wife is out of the house before I give it a good HT run.

for the small footprint and for HT I would consider a TL .
That is on my wish list to build for awhile now.


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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #2 - 04/21/06 at 14:42:40
 
series II have only 8mm xmax and can handle 'only' 300w. so my guess is that, with 450w to each of them they're bottoming out.
try to remove one of the lids and play some really low notes (like 10-15hz) to see if the noise you are hearing is really the drivers bottoming out or you have some leaks.
are you sure you wired them right ?
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #3 - 04/21/06 at 15:11:29
 
Sorry Adrian, I assumed the world centered around me, and that everyone had read the entire thread "amp to make Daytons happy".  ::)  :'(

My apologies, I didn't give complete information.

The Daytons I've got are the series II. They've got an xmas of 15.1, and rms watts of 350, 600 max.

They're here... http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-190

As far as wiring goes, they ARE out of phase since they're back to back. You know... something I just thought about, I can't remember how I wired the 2 coils on each driver. Don't you just run the wire to one set of terminals, then jump over the magnet to the other set. I'll have to pull the access cover off and check that. I may be second guessing myself.  :-/
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paulc
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #4 - 04/21/06 at 15:31:29
 
Damn Bob, it sure sounds like a wiring problem to me.

I have built three HW's and each one has been way more than my house can stand.  I use the 250watt plate amp for HT and bass traps in all corners of the room.
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paulc
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #5 - 04/21/06 at 15:34:29
 
On second thought, if your carpentry skills are anything like mine.............

The top port must be exactly centered!  All seams sealed tight with liquid nails or similar.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #6 - 04/21/06 at 15:42:50
 
paulc, I want to tell my boss I've got to go home for an emergency to check my wiring.  

As far as woodworking skills, at the risk of sounding arrogent, I would say better than average. (better than spelling) 9 ounces of Gorilla glue was used in the construction. I would say it could be used as a submarine if it werent for the 3 big holes in it.  ;D

I'm really worring about the wiring to the individual voice coils. I know the drivers ARE out of phase though.

If your rockin' the house with 250watts, somethings wrong with mine. - and it IS built to spec.

Bob
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DirtDawg
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #7 - 04/21/06 at 16:52:52
 
[quote author=Bob  link=1145573673/0#6 date=1145630570]...........
I'm really worring about the wiring to the individual voice coils. I know the drivers ARE out of phase though.

If your rockin' the house with 250watts, somethings wrong with mine. - and it IS built to spec.

Bob [/quote]

Bob,

I'm trying to work my way back over the other thread for something we all missed and I'm a little confused which driver you have. Series II and Dual Voice Coil are distinctly different and I hope you got the DVC which has double the Xmax.

Also, the total impedance that the amp sees needs to be within spec or it can clip very easily and that can sound like a "KLOP" inside a big box, but so can bottoming your drivers.

Are you still using the shakers? I remember they had a problem, but what's the latest?

Verify the wiring and the impedance.

One other question ... why did you turn the box upside down?
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« Last Edit: 04/21/06 at 16:55:08 by DirtDawg »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #8 - 04/21/06 at 17:58:58
 
I'M SORRY GUYS. I've got the series II's.  Adrian, you read correctly. Sorry, my head was in my butt.
Here's what I got...

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-130&CFID=4954...

DD, using the shakers occationally. I mounted them in the bottom of the seat cushion. Just under a sensitive bodily area. They need to be moved to the back I think. When they are turned up, it vibrates parts of my innards that don't need to be vibrated.

Pics of the shakers mounted are here...

http://community.webshots.com/photo/549522535/2690067230085868784FhZCXU

Bob
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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #9 - 04/21/06 at 18:08:14
 
bob, i actually read the topic before i posted. YOU said you got the series II. you must wire them in paralel and one out of phase. check that before trying anyting else.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #10 - 04/21/06 at 18:15:29
 
Yes, Adrian, you are correct. I've second guessed myself so much, I could'nt even remember what I bought. The are out of phase. Inside the box I "Y"ed the wires, (soldered them with heat shrink) then ran + to +, - to - to one driver, and + to -, and - to + to the other driver. That's ok isn't it?

Bob
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #11 - 04/21/06 at 22:28:47
 
wiring is correct for four ohms with one out of phase.

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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #12 - 04/21/06 at 22:43:16
 
What do you have for wiring, are the 2 subs on one channel of the legion amp?

If so, You might want to look into a sperate amp for your shakers.

Legion gives these specs.
225 x 2 at 8ohm
900 x 1 at 4ohm (mono)

I would parallel your subs and bridge them to your amp, works out to 450 watts a sub.  a sub on each channel gives you 225watts a sub, both subs on one channel gives you 200 a sub.

Not sure if those are RMS or just watts.

In any case, 450 a sub will make them much louder, plus you will be able to re-wire them to make sure the wiring is correct. (I assume it is already anyways.)

Abotu the knocking, that amp is defineatly not overpowering your subs, it may be clipping.

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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #13 - 04/21/06 at 23:11:33
 
J rock, You first thought is correct. They are parallel, bridged, mono. Tha amp has a green led for each channel, they start illuminating when things start getting loud. obviously they illuminate together. It has a red clipping light for each channel, and yes I have seen the "danger" lights which also illuminate together. I've heard the klopping with no clipping lights, and have seen the lights with some 'bad noise' but no klopping. I did line upper, and lower chambers with 1/2" automotive carpet pad. Really mad no audible difference.

DD, to answer your question, I flipped it upside, it just sounds better with the 2 ports on top.  color me silly.

Bob
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #14 - 04/22/06 at 00:18:45
 
perhaps the amp is not cliping, but the source is.  

How do you have the system wired?

If the amp is indeed fed by a source unit (i.e. reciever):
1. Turn the sub amp all the way down.
2. Place music in source and turn it up till you hear audible distortion, turn it down a bit. (Remember this volume as max volume)
3. With music still cranked, turn sub up until it sounds good, or you hear distortion.

Now your gain is dialed in for max output without distortion.
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #15 - 04/22/06 at 03:52:27
 
Bob bob bob bob bob,

I don't know why people keep trying the Daytons in the HWK.
Few have success.

The HWK is more of a club cab than an HT cab.  This is because of the port tuning.  Just plug the top and bottom chambers into a 6th order bandpass cab to see what I mean.  The center chamber has the magical quality of smoothing an otherwise double peaked response, but it doesn't change the tuning of the vented chambers.

That banging noise is definitely the drivers hitting the back plate.  This is happening because your sending material below tuning, resulting in loss of cone control.  Since you have 8mm of Xmax and a mechanical limit of only 9.2mm , you get bang bang bang with low frequency content.

The first thing to try is a different tuning.  Take the top driver out and play just the bottom one.  This will greatly lower the tuning of the top chamber.  Maybe it will sound ok to you for HT.  If that works better, then just mount the 2nd driver clamshelled to the bottom one.  If that still doesn't cut it, try taking off the bottom cap and listen to it laying on it's side.  That's not too far from the recommended vented cab for the driver.
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HT-EXT
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #16 - 04/26/06 at 17:24:31
 
No offense to anyone but I have Series II in both my HWK15s and have been a fan of Daytons ever since. I am not sure what to tell you BOB. It sounds like everthing is hooked up right and with IIs, plus 450w+, I don't think you should have any problem going low or loud. One HWK with two Daytons(hooked up the same as you) with about 300w will hit between 115db to 120db(3ft away) and rolls off hard around 28Hz to 25Hz depending on the material being played. Understand this is my set up and almost every set up is different. I also use the Ultrabass Pro EX1200(Behringer) if I need that extra punch or low,low bass. Besides sometimes when the whiskey is flowing my system doesn't sound loud enough for me either. Just keep on "BOOMING"  and you will figure out what you like the best.   HT-EXT
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« Last Edit: 04/28/06 at 17:27:33 by Joe_Eaton »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #17 - 04/26/06 at 20:41:59
 
Yea, my intention last week was to drag the big S.O.B. back into the workshop to increase the WAF visually, and increase my "acceptance factor" audibly.

Well, I got it into the workshop had it painted on the exterior, and lined inside and threw my back out flipping the damn thing back upright. So I put it back in it's home, fired it up, and drank some feel better juice for my lower back. Still haven't recovered.  >:(  Didn't notice ant difference lining top and bottom chambers with padding either. BUT, the wife says it looks prettier now.  >:( THAT was a kick in the balls.  :-X Cry All that work, no audible difference, bad back, and IT LOOKS PRETTY. ARRGG.


Liken' the looks of that Behringer HT-EXT

Bob
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Jet-Lee
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #18 - 04/27/06 at 12:59:32
 
Dumb question, but what does 'WAF' stand for?! It's been driving me nuts trying to figure out.

All I've found is Women in the Air Force, What A Fag, and somethin' else......None of which make sense in the context in which it's used on these forums.
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« Last Edit: 04/27/06 at 13:01:43 by Jet-Lee »  
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DirtDawg
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #19 - 04/27/06 at 13:22:53
 
WAF? Also SAF and SOAF, but there are others. It's a perfect question from a newlywed. You will soon come to appreciate the subtleties of WAF issues.

F=Factor
A=Acceptance
W-Wife
S=Spouse or Significant
O=Other

There are other ways to describe the same complication, but that's the idea.
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« Last Edit: 04/27/06 at 13:32:58 by DirtDawg »  
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Wreckinthehouse
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #20 - 04/27/06 at 22:37:39
 
I'm not sure what the Dayton's or other speakers cost, but when I spoke to Steve, he told me that the HW's were designed for Black Widows. Why fight it? Just buck up! Grin
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #21 - 04/27/06 at 22:50:17
 
Well Wreckinthehouse, here's what Steve wrote in the Housewrecker section....

"Using musical instrument woofers (ex. PEAVEY BLACK WIDOW) you get tight full accurate bass from 200 down to 40 HZ. Using subwoofers you get big warm full bass that can on command create Subsonic pressures lower than 20 cycles".

The reason I picked the Daytons is two fold.. #1, Steve said a SUBwoofer driver goes 20hz lower than the Black Widow, and #2, general consenses was the Dayton was a good choice (being a Sub-driver). But the big factor for me was the word 'subsonic'.

See what I mean?...  ;)

Bob

p.s. By the way, the Daytons were $90 each. I never checked on the Black Widow.
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« Last Edit: 04/27/06 at 22:52:31 by Bob »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #22 - 04/27/06 at 22:54:36
 
Checked Parts Express, $175 each if this is them...

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=294-303

Bob
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Wreckinthehouse
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #23 - 04/27/06 at 23:35:09
 
The Black widows are about 150.00 each, and if you blow one you just unbolt it and change the basket. I, like you have tried other woofers but i always put the Peaveys back in. Subsonic?, Id have to hear a major difference to replace my woofers, but the jobs that i play at, it buckles the walls. It's pretty embarassing when the pictures in the halls start hitting the floor, but hey thats what it,s all about
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #24 - 04/28/06 at 12:44:19
 
Wreckin', how many drivers do you have installed, and how are they positioned?

Bob
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HT-EXT
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #25 - 04/28/06 at 15:44:19
 
What up BOB? Have you ever consider laying the HWK on its side. I have one HWK15 standing up and one laying on its side with the top port firing at a concert wall. The one laying down seems to play lower and louder but that could be because of the wall. The Series II are almost "dead on" with the specs provided by Steve that is why I pick the Daytons. Have you every consider building the WO36 for HT? I "eyeballed" your pics and with a WO36 in front and the HWK behind would be a balistic or SUBsonic combo. Of course I might be throwing more trouble at you with another subwoofer in the room.     HT-EXT
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #26 - 04/28/06 at 16:21:16
 
rewire the drivers so they get more power for a little bit.

I am betting they just don't have th eumph they want.
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #27 - 04/28/06 at 18:25:46
 
Bob,

Isn't this for your HT ?  The HWK is not an HT subwoofer.  It is a great club cab though.  It simply doesn't do low enough to be good for HT.  As stated above, it was designed to roll off below 40hz.  It doesn't really matter what driver you put in them, that doesn't change the tuning.  You can try increasing the top chamber by installing your drivers only on the bottom baffle.  Save your back and just take the top driver out and give it a listen.  I don't like mine like that, but who knows.  It will definitely give you more bottom end extension.
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Wreckinthehouse
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #28 - 04/28/06 at 21:04:29
 
I have the magnets in the center chamber. Like John in CR stated, if you remove the upper woofer, you will get much lower sound but less control at high volume. The HW will also be much more efficient. Almost forgot your question, I have two woofers per HW.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #29 - 04/28/06 at 22:09:31
 
HT-EXT, The first location for the sub was laying on it's side, directly between the front surrounds with the 2 bottom ports facing towards me (first), straight up, then away from me. (now it's behind and right on me).
Yes I have checked out the WO (would be great to be able to find sub plans for existing Daytons) but havn't gone any further, wanted to 'improve' the HWK for my use, -- see response to John below..

J-Rock, Rewire? not sure how I could change existing circuit?? They are already bridged and parallel, 900 watts (amp knob is not even 1/4 of the way up and get the 'klopping' Cry )

John, John, John, John,  :D  Yes it is for HT(mainly),  music and gaming are a tie for 40% of intended use. I did my best to pretent you didn't say that the first time you said it. Have'nt been able to forget, it keeps haunting me. Now you've said it twice, I can't hide any more. Ok, I'll give the HWK another tweek or two before I start the 'subwoofer plan search' again. (That's how I found Decware in the first place) I'll remove the top driver and see how that does. But while I have you 'on the phone' what would be your idea of a good - to - very good HT sub? PLANS, not prebuilt. Now remember I'd like to use the Daytons again if possible, I mentioned in another thread I spent $2,200 for decking material (It's her turn to spend money since HT is "done enough" {her words Roll Eyes}, I get to be the one to build) So money IS an issue at this point.

Wreckinthehouse, (2) per sub, hmmm.

Bob

Hey John, your a HT guy, have you ever heard of an adaptor for component video to DVI-I, or one from S-video to component, or S-video to DVI-I?
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #30 - 04/28/06 at 22:29:42
 
the klopping is coming from your source then, especially at 1/4 volume

turn the bas down on your source and crank the sub amp's gain up.

Those subs will not bottom out and klop at that wattage, the amp I doubt could ever bottom them out.

The klopping therefore has to be a loose board, or your source clipping.  I assume your construction is plenty strong, so clipping will do it.

The box's intended use will nto fource it to handle less power or klop.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #31 - 04/28/06 at 23:00:45
 
You know J,   John had some good points about using the proper equipment for it's intended purpose, which I havn't. But you may have a good point there about maxing it out on such a low setting. I've played with receiver bass vs. amp setting, but will play with that again. Both before and after removing top driver. Two good 'points of reference' when it klops the worst, #1 Finding Nemo, when little girl is banging on aquarium, and #2 Star Wars III opening sequence with two fighters flying between larger ships. That opening sequence has two good lenthy LFE points that the HWK HATES! Basically any changes I make to the system, those are my reference points I check back with. Don't like "mid movie surprises" when I'm lost in another world, everything is great, and the F---ER starts bangin' again!  >:( Angry I can feel my blood boil.

Still open to suggestions on different DIY enclosure. Anybody wanna buy a HWK? Actually, I may step up and give it away if a replacement is found. (60ndown, your my hero) NO SHIPPING INCLUDED, I'm not that much of a man. $$$$$$$$

Bob

p.s. This happened on the same settings with 2 different Legion amps
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« Last Edit: 04/28/06 at 23:01:34 by Bob »  
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #32 - 04/28/06 at 23:26:26
 
Well, if it only klops at the very low frequencies, then it may be driver related.  I read it that it klops whenever tyou crank it, music movies etc..
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John in CR
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #33 - 04/29/06 at 00:57:58
 
Bob,

It's not the amp.  It's not the drivers.  It's the alignment, which on the low end is tuned somewhere in the mid 30's.

Your problem will come into play with virtually any vented design, whether it's BR, horn, or in the case of the HWK, bandpass.  That is your driver will go into over-excursion with very little power when you play frequencies below tuning.  In finding Nemo, you get a very strong signal down in the low teens and you're going to damage your drivers trying to play that with a normal HWK.

In all likelihood you have enough horsepower to get what you want with those 2 15" drivers.  With my pair of Tempests, which are comparable to your Daytons, Dan Wiggins of Adire Audio recommended to me a 6th order bandpass box (that's what a HWK is btw), but with much larger dimensions.  The dimensions were 56.6L for the top chamber and 340L for the bottom chamber.  Each was vented with a 4" diameter, 17" long vent with big flares at both ends.  200W gets you to 110db in room from 11-40hz.  Be careful not to fall out of your chair when Darla taps on that fish tank!  If interested, check out post#5 here for what would be a HWK on steriods:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=59473&highligh...

A much smaller alternative is going with small sealed boxes and using a Linkwitz transform to flatten the response from the lowest level you want to play.  You need the maximum amp power that your drivers can handle.  Then you say eg "I want extension to 10hz".  With your amp and driver max'd out at 10hz you do the Linkwitz transform above that which essentially whacks off the extra output potential as frequency increases, to net you a flat response.  It's kind of like building a car that is geared for mountain climbing, then driving it down the highway just in case there's a mountain to climb (Darla tapping on the glass).  There's no way this method will get you to 110db at 11hz, but with dual 15's it will probably get you to satisfying levels.

For either method, you could incorporate your existing HWK into the design, so that wood doesn't go to waste.

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« Last Edit: 04/29/06 at 01:00:25 by JohnF »  
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Mr Content
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #34 - 04/29/06 at 12:57:43
 
Bob Have a look at this site. You could get 10hz in a small cube, but you will need to get new drivers, and the amp to go with it.

Mr C

http://www.rythmikaudio.com/index.htm
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #35 - 05/01/06 at 12:47:48
 
John, I spent a few hours playing with WinISD alpha (not pro) on the numbers given by Dan Wiggins. The final result was a bizarre graph like I've never seen before. The line looks like the financial earnings of a company VERY QUICKLY going it the toilet. I'm not sure how you guys get those cool looking WinISD charts to display here? But the line starts on the left at -11.5db @ 10hz, and quickly drops to -30db @ 60hz. Could this be correct? Box numbers obviously taken from Dan, the driver numbers inserted from PartsExpress.

Intriquing the small box you mentioned, when you say small sealed boxes, and still use the HWK, are you talking about getting out the circular saw and cutting the top and bottom chambers away from the center, and sealing the holes?

Mr. C, I like your idea, but not an option financially at this point. Wood is cheap, I'll build a few boxes if I need to, but can't be buying drivers and amps right now.

Bob
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Mr Content
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Re: hz numbers on a 15" 2 driver
Reply #36 - 05/01/06 at 12:59:53
 
Bob sell what you have got to finance it. Grin

Mr C
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #37 - 05/01/06 at 13:11:54
 
Another good idea C.  I'll find out how much it wieghs, then call FedEx for shipping price to Australia, what was you address again??  :-*

BTW, it's painted gray now, to match my walls, but it can change colors very easily, just tell me what color you want.  :D

Seriously, I can't believe anybody would pay much for it, especially since my salespitch hasn't been very positive.

Bob
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DirtDawg
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Re: hz numbers on a 15" 2 driver
Reply #38 - 05/01/06 at 13:14:34
 
Bob,

You are right. If you use a super low 6th order alignment, you will lose efficiency. The reason it works is many drivers have power handling capacity that makes the efficiency less of an issue. You should actually see 2 humps in the response with a 6th order enclosure. One around the 10Hz range and another around 28Hz, if I can remember  correctly, using Dan Wiggins' design. The isobaric chamber should smooth out some of the unevenness of the alignment. BUT, like John pointed out, it will support your drivers at a much lower frequency with Dan's dimensions.

You might also try the driver placement that John mentioned for your current box with the drivers in the smallest chamber, and close off one of the two ports in that chamber.
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #39 - 05/01/06 at 13:41:27
 
Ok, just to make sure I've got this correct....

Step #1 Remove both drivers.
Step #2 Install both drivers clamshelled on lower baffle. (One magnet in lower chamber, one in center chamber)
Step #3 Seal one of the two bottom ports, leave large top port alone.

Is this correct?

Bob
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trashfire
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Re: hz numbers on a 15" 2 driver
Reply #40 - 05/01/06 at 22:58:48
 
Bob,
I can totally understand your frustration with the HWK and it crapping out at ultra mega low frequencies.  I had the same issue and it bugged the crap out of me.  

I'm in no way affiliated with, financially interested in or otherwise have anything to gain by recommending this but take at look at www.billfitzmaurice.com specifically the TableTuba.  I know you said you didn't want to buy new drivers but the driver for that enclosure is $40 shipped.  

I replaced my HWK with dual 15"s and 1500W with a tabletuba loaded with a cheap 8 and 150W and it blows it away.  The efficiency of a folded horn is incredible.  The proof for me was Master & Commander.  The HWK just flat out could not keep up with the cannon fights but the tabletuba rumbles ALL the way down.  It's quick thanks to the small driver but still unbelievable low and loud.

You can build it with 2 sheets of 1/2" MDF or ply so the wood costs are really low.  It's a bit intimidating to build because of all the angles but once you get into it, it's not that bad.  I built mine in a weekend.  Exterior dimensions are about 30x30x16.  

Not having built a WO or WO32 yet, I cannot do an apples to apples comparison but I can compare the TT against the HWK and the TT takes it hands down.  Add the fact that the TT is an 8" against two 15"s & 10x the power just adds to the margin of victory.

Hope it helps,
Chris
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #41 - 05/01/06 at 23:57:27
 
Bob,

It sounds like the sim you ran was correct.  In the thread where Dan made the recommendation I was soliciting advice to best handle 25hz and down using 2 15" Tempests.  He said that cab should get 110db in room from 11hz to 40hz with 200 watts, so 10db of room gain down at 11hz sounds about right and output would fall off rapidly above 40hz.

Now that you know how to work WinISD, see what is possible with your existing box.  In modelling, leave the top chamber alone and move the other driver up there and don't forget to factor in the 3L or so volume decrease.  That may be low enough tuning for your higher tuned chamber.  Then play around with port lengths for the other chamber (including the center chamber in the volume).  You may have enough volume there to get down close to 20hz without too much port velocity.  Forget about the teens, because that really does take 300L+.  I'm not sure what kind of space you have, but you might even be able to get away with just adding on to your current HWK cab and getting output down to where you want for HT.


Chris,
While I've heard that Bill's designs were pretty good, those are all for music and as far as HT and bottom end extension goes, I could build a 2ft3 box for a single shiva that would laugh at what any small box horn could do for HT.
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« Last Edit: 05/02/06 at 00:01:05 by JohnF »  
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trashfire
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Re: hz numbers on a 15" 2 driver
Reply #42 - 05/02/06 at 04:09:58
 
The tabletuba was designed as a home subwoofer for theater and musical applications.  It has a 13 ft path which gives it a very low fc which lends itself well to theater applications.  I can personally attest to it's excellent performance in HT.

If the small box horn (which does extend even lower than the $2k velodyne 12 I originally compared the HWK to) doesn't float your boat, build a bigger one.  The Tuba36 loaded with a 12" or 15" driver would absolutely spank a shiva in any enclosure.  The verticle baffle 15" version extends to like 15hz at 95db 1w/1m. Even if it falls flat on it's face and rolls off at 18db below that, you're still getting ludicrous output to bowel loosening frequencies without sacrificing the higher bass above 40 and 50hz.

There's a reason people use these things to entertain thousands of people at a time.  You're not going to find a Shiva up on stage at the next concert you go to.  I'd really like to see a 2 cube box with a single 12 extend below the mid-teens with an effectively flat response on 150W.  AND still do it for under $100 total build cost (excl amp but incl driver).  I just don't see it happening.

If nothing else, it's worth a try to learn.  I was looking at getting some stroker 15's or 18's for my theater when I found the folded horn design.  I've become enamored with the horn theory and learned quite a bit about what all those TS numbers mean and how horns work.  That's what this is really all about.  It's also a blast to see the look on people's faces when 1 tiny teeny little worthless 8 shakes their ass from 15 feet away.  Check it out, read the forums and decide for yourself.  

I personally will never go back to direct radiators for my sub needs.  That's my opinion and we know opinions are like @$$holes, everyone has one and they usually stink.  I'm not trying to put down steve & prop up bill or vice versa.  I just think in my situation which sounds similar to Bobs, I found a better mouse trap and built it.

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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #43 - 05/02/06 at 07:03:50
 
Well Trashfire that's big talk.  Why don't you send your little over compromised horn a 15hz sine wave and 50-100 watts for a while before you go around bragging about how great an HT sub it is.  I'm sure it does fine above 25hz, but subsonic it's going to be excursion limited rather quickly.

I'm sure that Bob would rather do it right this time instead of just building another stepping stone in route to getting the performance he wants.  He's already got drivers that can get him where he wants.  He has an amp that will do it.  He even has a good portion of the box already built if he plans things well with a very simple build to finish it up, but of course my opinion stinks.
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Mr Content
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Re: hz numbers on a 15" 2 driver
Reply #44 - 05/02/06 at 08:35:42
 
[quote author=Bob  link=1145573673/30#38 date=1146485514]Another good idea C.  I'll find out how much it wieghs, then call FedEx for shipping price to Australia, what was you address again??  :-*

BTW, it's painted gray now, to match my walls, but it can change colors very easily, just tell me what color you want.  :D

Seriously, I can't believe anybody would pay much for it, especially since my salespitch hasn't been very positive.

Bob [/quote]

Hmmmm..... I think I might have enough MDF, HDF, PLY. Solid Timber here already Bob, but thank for thinking of me, I appriceat it. Cheesy  ;D

Mr C
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Bob
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Re: hz numbers on a 15" 2 driver
Reply #45 - 05/02/06 at 12:38:01
 
John, you made me laugh, "I know how to USE WinIsd"  :-/. No, I can't USE it, at this point in my life, I can input numbers and look at the pretty line I've created. Just for fun I can play with the signal generator and attempt to blow my poor little PC speakers. But as far as using it intellegently, no. I've clicked on things that look like something I want to do, but it tells me this version can't perform that task. I've checked for updates but apparently this is the newest version. I need to check into WinISD pro I think. But it may do nothing more than provide me with more buttons to click that do something I don't recognize.  ::)

Slow learning curve with all going on in life. Beginning to think I'd rather be a lazy mooch and build from plans. (I've learned over the years I rather be the creator, than the designer) I feel like I need to have a night course at a local college to learn what all this stuff really 'means'.

As far how much room I've got to play with, Plenty. The area between the seating and back wall is about 11' wide X 6' deep. +++++ And for those of you that think I need a couple of Imperials, the rooms not that big. I've thought about it.+++++

trashfire and John, I'm enjoying the frendly discusion, please continue. I like to learn from other people. Do you guys think the difference of opinion may be the difference in reference points? Example; The pilot of an old B-29 bomber may think his is the cats meow, it does everything he could ever need or want. But, since he's never piloted a B-52, which is sooo much more capable, he's got no refence point, no idea that such a better piece of equipment exists.

Mr. C, glad to here your doing ok in the lumber department. Just say the word and it could be yours! Well, maybe not just yet, we'll see how it turns out the next time it comes back through the doors of the "Bob the Builder" workshop when John gets finished with me.  ;)

Bob
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trashfire
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Re: hz numbers on a 15" 2 driver
Reply #46 - 05/02/06 at 14:42:07
 
How do you know I haven't sent it a sine wave sweep?  I wouldn't be lauding it's worth unless i've put it through it's paces.  The driver has an xmax of 16mm so there's plenty of excursion.  My front window resonates at 42Hz, the side ones at 35, the large painting in the hallway (more likely the wall itself) around 25, the dog gets mad around 18, etc etc.  If you want or need more, you can put an Eminence 10 (HL10) in it, throw 300 watts at it and probably do damage to your hearing, your relationships with your neighbors and your criminal record.

If you want a 1 note wonder, build a giant 6th order BP. It's going to sound like crap but it'll be loud.  Have fun trying to blend it with your 3 other tuned wonders and then your mains to get the full audio spectrum.   A Bandpass is just that.  It's a "lets focus our attention at a couple frequences and play the hell out of them and ignore the rest".  What good really is the movie going experience if a girl banging on the aquarium massages your back while the explosion of a bus allows you to hear the phone ringing in the next room?  You need to be able to play way down low for today's LFE tracks but still blend it well with the frequencies in the 40 to 80/90/120 range (basically however far down your mains will play).

I'm building a Tuba36 right now.  I should be done in a couple weeks and I'll have a comparison to that as well.  I'm fairly confident I'll find it blows everything including the TT away.  That the TT can handily defeat the HWK, I can only imagine the orders of magnitude that a Tuba36 would outperform a HWK and do it across a MUCH wider range.

You may be right Bob on the reference point issue.  I've spent a good number of hours and days reading up on enclosures and theories behind them.  I'm in no way claiming to be an expert and anywhere near the knowledge or experience of most of this board and certainly Steve & Bill but I know what I like.  The theory behind horns just makes sense.  A horn (as it's been explained to me) is basically an acoustic leverage device.  A small driver exciting alot of air at one end will excite a large amount of air at the other end of the horn thanks to an exponentially expanding throat.  That's why you don't need a huge driver and kilowatts of power for huge sound.  The imperial cabinet is a type of horn and you see how much everybody here loves the bloody things.  I just don't have the room or I'd probably build one or two.

What I've found in practice supports my opinion that horns rule, a good sealed box will work if you can't have a horn, vented if you're desparate and bandpass if you're only concerned about SPL drag racing.  
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Adrian D.
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Re: hz numbers on a 15" 2 driver
Reply #47 - 05/02/06 at 14:57:14
 
i say both john and chris should build the best they can and send it to bob for a comparison.  :D
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« Last Edit: 05/02/06 at 15:03:11 by adi_ro »  
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #48 - 05/02/06 at 15:41:33
 
Every few months someone brings up the tuba designs and I can't remember why I didn't like them so I check the site again and remember very quickly.

Even on the largest tuba, lf rolloff starts around 40 hz and is down 10 db or more by 20 and still dropping hard, measured for corner response.  You would have to stack at least one more, and probably 3 more, to get close to flat down to 20.

There are much smaller, albeit less sensitive ways to do this.

I've read reports of the WO going flat to 27.

If you want a traditional horn flat down to 15 the mouth is going to be roughly the size of the cross sectional area of your listening room.
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #49 - 05/02/06 at 16:00:09
 
Once again Trashfire, if your little overcompromised horn sub is so good, why are you building a different one to replace it?  I'm not knocking your TT.  It looks like a real performer for its size.  

I'm just trying to help Bob do something with what he already has.  An hour or so, and a sheet of plywood and he can find out if it's a fit for him.  He wouldn't even need to change anything that he already has.  The wiring, drivers, etc can all stay in place.  Just take off the bottom cap, add 4 rectangular pieces of plywood to extend the bottom chamber and cover the existing ports, add some shelf braces and a port, and the old bottom cap now becomes an end insert instead of a cap.  

Now that I'm thinking how easy this would be, I may have to dust off my old HWK12 and do a HWKenstein conversion on it.  I already have the drivers, wood, and flared ports required.  Plus it would satisfy my curiosity regarding the effect of Steve's twist on 6th order bandpass (the large isobaric air cushion), using similar dimensions recommended by Dan Wiggins for an over the top low tuned sub.
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