With the lowered ceiling above your PJjust throw another fan in parralel with the fan on the projector.  The place that fan in the ceilign tile.  Build a box with a cut out for you lens, so just the tip sticks out.

Fan sucks heat from projector into lowered ceiling.  Movie goers are totally isolated from sound of fans.  And Pj is better braced against vibrations.

Heres a pick: (minus the walls, so you can see)



Notice the awesome fan I drew up?

Anything I have to keep cool I keep it cooler.
I tend to replace anything with a fast moving loud fan with a larger slow moving one. preferably with twice the CFM.
Nasty habit left over from Being a PC modder and overclocker.
I also undervolt the oversized fan and then add or subtract resistors to find the temp I am comfortable with.
this applies to 12 v fans. you also have to watch for keeping the voltage higher than start up voltage.
if it don't spin at 7V you need another fan to use with a lower startup voltage, as an example.

I know you can build a circuit to solve this but I am too lazy.

Blowing air in and in bigger quanitities leads to more dust unless your filtering and then you have filters to check.

Bob,

Before the numbers, please tell me exactly what you did in the way of mods first.  After reading that you painted a deck, I'm not sure what to expect.

Sorry Bob, just couldn't resist.  I already knew decks were stain only (if anything other than just sealer).  Before I may have tried paint too.

It sounds like you did everything right.  What did the sub sound like?  My guess before hearing your result is that you wired in series instead of parallel (sorry I didn't mention that before) or maybe a receiver setting, amp problem, loose wire etc.

Wiring-  Series, parallel or separate?  Series means through one driver to the other then back to the amp.

Did Mr. Klop show up?

What were you playing during your test?  Test tones?

I have an SPL meter.  How many times have I used it?...Less than I have fingers.  How many times have I used it for a sub?...None

Did you put Nemo on and see if it felt like you were in the fish tank when Darla was tapping?  That's a really good test.  Do you have Harry Potter 2?  The willow whomping the car is also good because it has a good variation of frequency as it groans with a nice impact to really feel when it slams to the ground.  Also, the train scene about a minute earlier.  You should feel the near miss of a raging locomotive.

[quote author=John in CR  link=1145573673/105#110 date=1147703593] Series means through one driver to the other then back to the amp. [/quote]

...."back to" the amp?  The "back" is thowing me off..?
Positive and negative to the sub, then "Y" to each individual driver, like a fork in the road.

Nemo on DVD was borrowed, the kids only have it on VHS. I won't even install a VHS in the room, imagine what 480X480 looks like blown up that big....  :-X

haven't tried tones with the meter. The Potter movie you mentioned is on my 'needed' list.  :)

Bob

[quote author=John in CR  link=1145573673/105#113 date=1147711209]Bob,

First, shame on you for testing your sub on Mothers' Day.  You burned up any credits you had and need to do something extra special to get some back.
[/quote]

Fortunately we have a very stong marriage ( ie...she tolorates my toys)

[/quote]
Second, your tests don't really mean much at all except that they play up to 105db+ at the seating position and that you're playing low enough frequency info to send both the HWK and ported alignments into over excursion.  What it doesn't tell you is how low in frequency you were getting what output.  
[/quote]

Is there something a fellow could get to measure hz and db simultaneously, or would that be yet another toy in the hands of someone not needing more toys?

[/quote]
Those LFE's have a wide range of frequencies in them.  The cannon shots, for example, probably have a burst across the entire range below the XO point set on your receiver all the way down to about 10hz.  It doesn't surprize me at all that the output was close to equal.  What it doesn't show is a comparison at say 20hz or lower.  Could you hear/feel a significant difference or were you too busy with your new gadget?  Was it enough feel or do you need more, because 105db is pretty darn loud?
[/quote]

I believe it was you that said something about the level of sanity regarding your subs.  :) Am I correct  ;D  Yes, I was mainly concerned with the toy last night, but it seemed to be better. Over the next few days, I'll have some real play time to actually HEAR it.

[/quote]
If you like the tuning with the top on, that will give you the ability to go louder, because the top chamber is helping to control excursion better than the free air of the open top.
[/quote]

Would making the top port a smaller diameter create more air restriction, giving the ability to go louder?

[/quote]
Lower tuning (longer port) will enable you to apply more power (go louder and lower) before going into overexcursion on the lowest material.
[/quote]

Install a 90 degree fitting on the PVC to add additional pipe?

[/quote]
If after trying all of that you are positive that you want more output,
[/quote]

Absolutely

[/quote]
OR make your room so it can be closed,
[/quote]

Very hard to do with the archway. Light switch just out of view on right side of arch. And there would be three doorways in very close proximity of each other, all swinging towards each other.

[/quote]
If you are sure you need more, I'd try HWK size first with only one driver, in place of the top cap, and tuned even lower with say a 17" port.
[/quote]

I'd like to go down this path.


...Gee, I hope all this quoting works.

Bob

Google  "ttg test tone generator free" and download Timo Esser's tone generator that is free for a month.  If your puter isn't connected to your system, just make some tone files and sweeps and burn them on a disk.  Then you play a frequency from the generator and measure it with the SPL meter.

Be absolutely sure your other speakers are set to small or are off for running that kind of test or you'll blow them for sure.

Keep the port outside the box, so you can easily try different lengths first.  Don't put it inside until you get to the tuning you want.

You might be able to get away with a matched pair at the front of the room in the corners with the right color scheme.  I think that will load your room better, but that's probably just a few dbs at most.

Before building something new, check the SQ and max limits with the top cap on.  Also with the top off and lower tuning.

Yes I think a smaller diameter port and/or longer port will help control excursion to a lower frequency, but too low tuning could cancel some output from the big chambered end because they are at a different phase.

Just for grins, next time you have a sheet of ply or mdf, before you cut on it, place it over the opening leading out of the room and have someone hold it in place while you play some loud LFE's to see how much more room gain is possible.  That way you know whether or not it's worth trying to figure out if it's worth any trouble trying to make that work.

I'd say measure and listen to what you have first.  Going for extreme output is kinda fun, but realistically it will never be used, because your volume would be up way too loud for the rest of the audio spectrum.  Plus, if you do use it, you'd have to start worrying about cracks in sheetrock joints and other damage to your house.  Also, Dad's setting the example now, you may not enjoy the 7yro's taste in music in a few years and he/she will want to blast their's too.

Keep in mind that HWK size is about 100L too small for true EBS tuning.  It looks like Bassboy and I are going to try some new that we've been discussing over in the HT section.  If my 10hz version works, using a 15" driver, then that might be your answer once you want to cut some wood.  Tom Danely, a renown sub designer, is getting 120+db at 20hz with a pretty compact model with a 12" driver.  Mine will be 8ft x 1.5ft x 3 or 4ft and it looks like you have room for that behind your seating area.  http://news.ecoustics.com/bbs/messages/10381/169045.html

[quote author=John in CR  link=1145573673/105#116 date=1147718782]
Keep the port outside the box, so you can easily try different lengths first.  Don't put it inside until you get to the tuning you want. [/quote]

So, let me get this right.  The total port lenth isn't the issue, it's how much of it is inside the enclosure? Does it affect tuning at ALL, or just not enough to worry about for tuning purposes only?

Bob

I have been whatching this thread for some time.  I believe for home theatre you need to stop and step back.

Now realize the HWK is not going to work.

Now start over from scratch.  Working around the space, drivers and amps you have, design a new enclosure.  For hometheatre and double duty as music, the only option IMO is a low tuned ported enclosure (PR if needed).  

No offense, these ideas are great, but I think you have a much better idea of what you want, and can easily get it without haveing to modify a box.

And guessing at volumes and ports is fun for a few hours, but after awhile grows tiring, I suggest a program to model something.  Even if it is just to get a starting point...

I understand that much, I am suggesting that he DOES start over.  

Of course after testing the HWKenstien.

LOVING the discussion guys, keep going..  ;D

Weekends are best for letting the HWK "stretch it's legs" so to speek. So I havn't done much listening at high db's during this past week. I do believe it sounds better John. However, I am looking to go lower in the hz, and higher in the db's.  

Tell me if this correct..."Adjusting the port lenth will only change hz range, and not affect db's or prevent driver bottoming out".

If this is true then I would be interested in exploring other modifications. ie, trying iso loading drivers mounted ON the top cap, increasing Vb, or...?... letting more sawdust fly?

Tell me what this would do,...
- Lay original HWK on it's side, facing dual port holes up
- Build carbon copy HWK enclosure facing dual port holes down
- Lay it on it's side, on top of other HWK (the, now "quad holes", mating with each other
- iso mount drivers in the top cap of, say... bottom HWK
- install the adjustable port(s) in 'what would have been' the top cap of upper HWK (now the end of the upper HWK)

Anybody for some ascii?.....
                                                         
                                                         
     -----------------------------------
     I                                               I
     I                                          -----    /__ ADJ. PORT
     I                                          -----    \
     I                                               I
     --    ------------------------------I
     I                                            __/
     I                                           [        /___ ISO DRIVERS
     I                                           [__     \
     I                                               \
     -----------------------------------I

Bob

turning the knob up just creates the horrible 'klopping' sound from drivers hitting mechanical limit.



ah, the above quote is from bobs first post and seems to be where it all started.seems to me like you need heavier duty drivers. 900 wrms @ 25hz is gonna punish most mediocre drivers.

[quote author=Bob  link=1145573673/0#3 date=1145628689]Sorry Adrian, I assumed the world centered around me, and that everyone had read the entire thread "amp to make Daytons happy".  ::)  :'(



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

[/quote]

450 still pushes them beyond theyre ability.especially when you really want all that output below 50hz!

Hi Bob,

Lower tuning by lengthening the port will give you excursion control down to a lower frequency, so playing the same content as your last test, you should be able to turn it louder before running into excursion problems.

The tuning frequency of your box is determined only by the net volume of enclosed and the diameter and length of your port.  Increasing the volume, lengthening the port, or decreasing port diameter lowers tuning.  Content below the tuning frequency quickly causes excursion problems, because the alignment can handle very little power below tuning.  Typically a "rumble filter" a high pass filter is used to protect your driver from content below tuning.

The T/S parameters of your driver determine what size box is needed for optimum performance tuned to a specific frequency.  Isobarik loading cuts the Vas in half and the driver only needs to see half the box size for the same performance at a given port tuning.  With iso loading you don't need any more box than you already have.  In fact, the way you have the drivers mounted now gives you an effective volume equal to almost 340L for a single driver and moving the drivers up to the top cap wouldn't help.

At this point I'd suggest trying 2 things:  

First, see if you can live with the SQ and tuning of your current box with the top cap back on.  That alignment will give you more excursion control down low, but it will also limit integration with your mains.  As you saw last weekend, it will allow higher output with the content you were playing in your test.

If that setup won't work for you, then try tuning the existing setup to a lower frequency with some longer ports.

You can use the LFE's you used before for your testing to give you an idea of performance, however, you don't know low that content goes.  I'd mix some more LFE's in for that kind of testing.  Let's say you're tuned to 15hz and the LFE's have 10hz content, you won't be able to turn it very loud and see how your sub performs from 15hz and up.  If you tune to 10hz, then you'll give up a lot of max performance compared to 15hz tuning.  That's where the tone generator comes into play, because it will enable to properly test performance and extension.  Then once you determine the desired tuning frequency, you know what rumble filter you need to protect your drivers which will enable you to crank it as loud as you want without the banging noise no matter what LFE's you send to it.

The bottom line is that you really don't need to let any sawdust fly, because HWKenstein won't integrate with your system.  After trying the stuff above, and you're still feeling adventuresome, then you could try just a single driver (not iso) mounted in place of the top cap using your current port.  That will give you a slightly underdamped alignment close to an EBS alignment.  It won't give you any more output or driver protection below tuning, although it would lower tuning by a couple of Hz compared to what you have now.  It will just tell you what to expect with 2 of the same boxes.  Just test it and add 6db.

You already have butt shakers, so realistically you don't need super low tuning for your sub, you just need a rumble filter.

Even more good advise John, That'll keep me busy for awhile.  ;D

Hey 60, a 10.6 lb magnet, OMG! 3 inches Xmas, OMG!!! that's cool, but they arn't very forthcoming with prices are they?
Yes, to answer your question, I am serious about the room. Usually as serious as my budget allows  ::)
2X4's and drywall are cheap, so you can do cool things with design that increase the cool factor and help acustically (hopefully)
As far as the butt shakers go, they stopped working last night!?  ???
I've heard may referances to rumble filters, mostly seeing plate amps with the filter built in, but I'll do some research on an 'add-on' filter. Sounds like an interesting idea.

....and now for a completely different idea.
You may have see the pic of the rear wall. The drywall is about 9" from the concrete foundation wall, due to the upstairs 4" sewer pipe running across the wall. I didn't want "the ugly box" that a lot of basements have that incase HVAC and plumbing. Soooo, I brought the wall out. The point to all this is, ... IB. Is it feasible? Is it feasible with my drivers?

I've seen the radical set-ups on the infenitly baffled site. Neat ideas

Bob

[quote author=Adrian D.  link=1145573673/120#133 date=1148056136]the lower the bass goes the more power the sub is getting. gains untouched. [/quote]

Well Adrian, That seems pretty obvious now that I see it in writing. I'm fairly dissapointed, and embarassed in myself for not realizing that. Several hundred watts at 100hz is much easier than at 25hz. Thanks for the reality check. That's why you received that A- !

Bob

[quote author=Bob  link=1145573673/120#134 date=1148058139]

Well Adrian, That seems pretty obvious now that I see it in writing. I'm fairly dissapointed, and embarassed in myself for not realizing that. Several hundred watts at 100hz is much easier than at 25hz. Thanks for the reality check. That's why you received that A- !

Bob [/quote]
rotfl, i've topped my previous scores on all exams this year. i couldn't believe it.
hmm, i never applied anything i learnt in school, except maths

60, Good bass from a couple of used 15"ers outside is different from <20hz in a movie soundtrack though, don't ya think?  I'll never say the HWK doesn't crank. Ever. It'll knock your socks off with a good source for music, no doubt about it. Steve has a helluva design there.

It just won't go low enough, loud enough on movie soundtracks for psycho's like me.

The IB thing was a passing thought/daydream. Not something I had my heart set on.

I do know the difference between a Ferrari and a Yugo, but I've seen too many 'hotrodders' that can build a rod that would keep the Ferrari looking nervously in the mirrors for a fraction the price. (That's where I want to be, I'm just having a hard time getting there.)  :)

Bob

bob...and john,
forgive me for flogging a dead horse but, if bobs drivers are bottoming out, doesnt that mean they have reached the end of their capability, and to get 'more' you either need more drivers or a 'better' driver? bob have you tried just a straight sealed box? apparently the roll of down low is 'best' in a sealed enclosure, also the subs might be able to handle more power? just a thought. personally i would have thought a pair of daytons and 900 watts would be more than adequate for watching a movie? cant imagine what your trying to achieve tyranosaurus rex @ realistic levels would require a 30 ton creature jumping up and down outside your door.i wont comment further, john is way more qualified to asist you than i am. but i do believe some of the 'hype' those beastly subs sure do pack some punch.

Bob's drivers are fine.  The HWK is not a LFE sub.

The HWK design ports at higher frequencies for the CLUB bass its meant to be used for.  Below these frequencies the enclosure does little to curve the driver's movements.  Hence the bottoming out.

Those DD audio subs will nto work for HT, a FS of 32Hz makes them unusable for sub-bass frequencies.

The Rlp subs might work, but again I do not believe in their SQ.

So John is absolutely right in sticking with your series 2 woofers.  They have a low Fs and a decent power handling.  Not that Power is that much these days.  Linear throw is what will determine the viability of any woofer for sub bass frequencies, 2 15s with 12 mm xmax or 24 mm of travel will move plenty of air.

With that said, John is again right in his thinking.  I just differ slightly in that I believe you need to get out of the moding HWK scene and start over.  There are many different options to explore:

~Low Tuned Horns - Although Huge they are my favorite type of Bass
~Transmission Lines - The main objective of these enclosures are as "Bass Enhancing devices."
~Low Tuned Large Boxes (Notice "boxeS"  Stereo subs for better room node excitiation.)


I think Bob really needs to step away from the ISO config though.  HT is all about air movement, ISO halves his capability when compared to 2 seperate 15s.  The only gain being a smaller enclosure and decrease in even order distortion due to suspension non linearities (Which I suspect these daytons have few to begin with).

Responses range from narrow bandwidth to wide bandwidth with typical responses down to 13 HZ on all three models. Box can be built for 8's,10's, 12's, 15's or 18 inch woofers.  Note: The design is for a 15, however the the box can be scaled down (and so the performance) to smaller drivers but you will have to specifically tune anything below the original 15" design.
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.  


thats a quote from decwares hwk page. i believe the hwk IS able to produce very serious low bass.how much lower than 13 hz do we want to go?

60, If I understand correctly, drivers (cone travel distance) can be controlled by how much air is allowed in and out of the enclosure.

Playing with airflow restriction is a form of "brakes"/"shocks" for the drivers, changing the max cone travel.

So if this is true, to continue the automotive analogy, it would be like antilock brakes, or traction control. The system allows life to happen "as it will", until it see's something it doesn't like, then it interveens [sp] and reigns it back in just before bad things happen (tires lock up, tires spin, driver/cone bottoms out)

.....or, this could be complete bullshit. Please correct me if I'm wrong.  

Bob

I don't have any means of measuring hz, but this thing is not getting NEAR that low. I've played sweeps a few months ago from 150hz, down to, ummm..... 20?.. 25???
Sweep, or more like 'steps' when one hz at a time. They trailed off badly, almost got QUIET below,.... umm, 40hz? Just about the time things started getting GOOOOODDD.


Bob

(I believe my ears)

I need to run the sweeps again, just for 'grins'.

60,

I appreciate your enthusiasm, but the HWK is not at HT sub.  In the good sounding aligment making use of the big iso chamber, the upper chamber (lowest tuned one) of the 15" version of the normal HWK is tuned to about 45hz.  If you put the driver(s) in the bottom baffle only (unbalanced sounding IME), the top is only tuned to about 35hz.  The alignment definitely allows for extension below port tuning, but none of the driver arrangements are going to give any kind of significant performance in the teens no matter what driver you put in them.  The HWK is for music.

With Bob's current configuration, the big chamber is tuned to about 19hz, and with the magnet in the top chamber and the cap on, it is tuned to about 47hz.  Bob, now that I've put the calculator to it, you should test the SQ and limits like this, call it the HWK-HT.  If you want to try 15hz tuning, you need to add another 10" to that 13.5" port OR you could leave the vent the same and mount the drivers as the top cap (14-16hz tuning).

Bob, if you can make the 6th order bandpass (ports top and bottom) work for you SQ and extension wise, that's probably your best easy thing to do, since the top chamber helps control excursion below tuning better than the ported alignment (driver open to the room).  

Put the top cap back on and try to integrate it with your mains and play some of those LFE tracks.  You may have gotten lucky and be done for now, at least until you build some new mains.