OK bassboy, John gave me a couple ideas, we're trying the small/easy/cheap version first. If memory serves, here's the current configuration;
One hole is closed
Other enlarged to fit 4" PVC, I think it's 17" long
Drivers clamshelled in/on top baffle
Drivers out of phase
Amp is bridged (900W)
Top lid off, then on, then off, now it's on.

You know 60, I saw your mug on the other post. It's scary how much we look alike.

Bob

[quote author=Bob in St. Louis  link=1145573673/195#202 date=1149623422]By the way 60, --"bass, the final frontier!"?

Do you really mean it?

Bob [/quote]

its a play on words with startreck (1st series) and my love of bass

"captins log......etc etc.........................."

60, I was trying to ---  :-* --- with the 'frontier' comment, you didn't fall for it.  :)

I've quoted that very same line directly from the "pretty picture page" of the housewrecker ad.

It's been shot down many times. much to my dismay.
Steve hasn't devulged [sp] how he got there from here.  :'(

You never answered my question about your HWK and the critters.
You got pics yet of the landscape ?

Bob

my only measureing tools are my ears, what critters?

research normally says 20hz.  But I feel (after reading some articles on ultra low high SPL sound, that we can hear below that.  It's just that our sensitivty to these sounds drop off at such a large rate, the sound level required for us to HEAR 15 hz is extremely high.  Normally we feel these sounds before we hear them.

An excellent example would be the large Barges that float down the Mississippi nearby.  When I am laying in bed at night I can hear them.  And while I listen I can count the peaks in the sound.  The frequency basically.  Now wether this is the beat effect or actually a wave I am hearing is still to be known...

Bob, I have to admit that I haven't done the calculations on any of the suggestions John and others have posted.  I have full faith that if John says the box is tuned at 19 hz, then it is.  If you chose the right length of port, it should perform as described.

But just if you want to be sure, plug the driver's specs into WINISD (it even allows isobaric loading as an option) and model the suggested box.  Then go to the next tabs and change the box size and port length to your box size and port length.  What you see in WINISD is what you should hear in your room, but with a bit of room enforcement on the low end, and even more for corner placement.

Keep fiddling with WINISD until the curve looks like what you want to hear, it's fun and free.

Try playing with flared ports too, it's good for you.

The bottom 2 chambers of Bob's box nets to about 155L (net of driver and port).  With the 13.5" long 4" port the tuning is just above 19hz, but with that corner placement he's getting an effective length of over 15".  With the isobarik loading, the drivers are acting the same as a single driver in a 310L box.  It's closer to an EBS type alignment but with a small box.  Even though he could lower the tuning, the port would turn into a problem because it would get so long.

So no Bob's box isn't flat to 19hz, but the few db sacrifice for the added shelf of extension is offset by some room gain.  In room, Bob should be pretty flat down into the upper teens even though his layout doesn't give him maximum room boost.


Bassboy,
I'm pretty sure that 95db on 1 watt at 20hz is a pipe dream (excuse the pun).  I think only a giant bass horn or multi-driver rig will do that.

The Tower of Power does 95 db.  My traditional design models at 93 in open space.  With Transflex loading, corner loading and room gain I am hoping for 95 db at 1 watt at least way down low.

I would be thrilled with that level, and I am hoping for that much volume but we'll see.

Bob, overlooking the DVC issue, the end results are not irrelevant.

The important thing when designing EBS ported is the box and port tuning.  As long as the box and port are tuned to work together, the driver is the only responsible for putting out whatever it can at the requested frequency.

The box will output whatever sound the driver presents it with at the box's tuning frequency.

The problem comes into play when you tune the box and port WAY out of the driver's range, which you haven't.  The cost in that case is sensitivity, because the driver is struggling to make sound way below it's resonance and we've all seen the FR graphs that show heavy rolloff around fs.

I strongly urge you to play with WINISD, you'll learn more there much more quickly than anyone can explain anything.  It's an excellent visual tool that you can experiment with.

Bob,

It would be nice to know once and for all which drivers you have.  Back on page one you gave us a link to these, which have 15mm of Xmax (that's almost a 6db difference at the bottom end):  http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-190

Let's get on the same page before proceeding.

Bob, WINISD cannot model the HWK or 6th order bandpass but it does very well with isobaric vented, which is what you have.

I'd go through the motions but I don't post pics so it's meaningless for me to do it.

John, I don't know where we're at now in the hz department, but I think I'd take the 15hz/rumble filter idea over the +6db gain since I'd have to build two boxes twice the size of my existing one to get there.
I'll take bassboy and your suggestion first. Remove some wires, listen to the mains then slowly add wires/equipment and gentle tweek along the way.

After I do that, I think I'll play with room treatments.
This is cheap/easy, don't laugh if it's a dumbass idea.
Take all of the cushions from the sofa's / loveseat's from upstairs furniture and line my walls with the cushions.

I've got to think that the room is playing into this. Despite how much time/effort I put into the room (with acustics in mind) that it turned out good enough not to need SOME form of absortion/diffusion.

mattresses on the celing? man alive, i laugh at myself sometimes trying to move my hwk and other subs, im sure they weigh in excess of 100lbs and awkward as a dead elephant . but im sure i would collapse into a ball of hyseria trying to fix a mattrress to my celing, bet the wife would love it 2

60, "AFRS" in the other 'active' HWK thread just told me the HWK is 140 pounds. (10 stones BTW, just in case that's your form of measurement.  ;))

John,  mattress is a good idea. I've thought about that, but I'm too lazy to drag a "califorina king" mattress down a flight of stairs.  ::)
Might rob the kids crib mattress (but it's plastic coated)
Or my son's 'twin' mattress  ;D

Cieling tiles are USG 2X2 acoustic, (very heavy compared to the cheap/standard white one's) They've got a very agressive texture on them.

Bob

[quote author=John in CR  link=1145573673/210#224 date=1149718674]If you want to see what bass traps might do, haul a couple of mattresses down there too.  Are the recessed areas on the ceiling in front of the seating area reflective or do you have acoustic tiles up there too?

[/quote]

cmon it was a fair misinterpretation? first matresses get mentioned and then the celing?

60,

Are you sure you aren't from Mississippi?

Those of us from Louisiana thank God on a daily basis for giving us Mississippi.  That way someone else gets to be #50 in almost every category.

Hey 60 don't feel bad about being 50.
Canada is the state that Americans did not want.

Thats a joke. in case  put anyone in a crank.

Funny you should mention the mattresses ( not the ones on the ceiling) I have a heck of a time getting my wife to throw out old mattress. maybe I could convince her to recover them with nice fabric and store them were the stereo is. Then I could get the stupid things out of my office.
Its so quiet in there I can can't hear myself think and I have to, or I don't think.
could be the reason for the last 100 or so posts  :)

[quote author=Gex  link=1145573673/225#233 date=1149854950]Hey 60 don't feel bad about being 50.
Canada is the state that Americans did not want.
[/quote]
Really?
Because I always thought Canada was the state for Americans that aren't liked amongst other Americans  :D
Except for Alaska, that's an even further, more boring, exile.

Bob,

You're getting some bass trapping with those interior walls over the concrete walls, but they're probably all tuned the same.  Next time you can incorporate a panel bass trap design into the construction at essentially no cost.  I did that in my room and my entire room is a giant bass trap tuned to a very wide range of frequencies.  I don't need any additional bass treatments.  Your room probably isn't too bad at handling bass either.  A LF tone sweep will tell you a lot.

How much air volume do you think is enclosed with that back wall?

How difficult would it be to move that front cabinet/shelf unit away from the front wall?

60,

I thought you were changing your name to 40nUp.  You understand that one don't you?

[quote author=Bob in St. Louis  link=1145573673/240#240 date=1149873260]Are you looking for the volume behind drywall including the 4" insulation, or volume between back of insulation to the concrete? [/quote]

If it's less than 100cuft don't worry about it.  If it's more, then approximate total volume behind the drywall.

Quote:


I was hoping just a handful of screws holding the whole unit to the wall.  Move the light fixture on the right.  Move the cabinet unit out 18-24", and build a new wall with the airspace behind to house 1 or 2 IB manifolds.  Then just replace one of the panels with a grill to vent it into the listening area.  You sub would be out front where it belongs.  Extreme extension and output is easy.  No worries about integration with mains up to 80 or 100hz.  Your projector can move back and you get a bigger image ratio, and no big ugly sub to hide.

You got me thinking John.  

Talk to you Monday. (here in the 'upper 50') Don't know what time it is there.  :P

Bob

John, I think two things have helped my rig.
#1 Your advise on the sub. The tweeks have helped. I've played with some of those car audio bass cd's (you know, the woofer torture discs). This sub could be used for a room fan. The air coming from the lower port is amazing (scary actually). WITH NO KLOPPING.  :D

#2 My maturity level. I've turned down the overall receiver/surround volume, and turned the sub amp up, quite a bit actually. I suppose I was so interested in the HT "escape" that I thought the entire experience had to be loud. Like a good song you crank up. (However, a 2 hour long cranked up movie leads to fatigue.) But was still looking for the 'punch' from the sub. Well, at that volume, the sub was already at 90%. Not much headroom left. So, turned the receiver down, sub amp up. Gives it the nice little suprise when the movie requires it. Didn't really change placement so to speak, but twisting it on it's axis so the waves have to take a different path has helped somewhat.

I guess I'm an official member now of the housewrecker club. One of my favorite cocktail 'hurricane' glasses I got from Bubba Gump's Shrimp Company in Chicago broke.  ::) I truly had mixed emotions about that one. Pissed that I broke it, but had an uncontrolable grin as I walked past my wife to get the vacuum cleaner...... Thinking to myself as I cleaned the broken glass, "Yea, I got me a badassed sub, I can break shit now."

I'm beginning to realize some of my unhappiness with the system is due to me. I've always had a problem with wanting to make something that works perfectly fine, better. We all know my setup would not be considered audiophile grade. I hear you guys talk about your systems knowing mines nowhere close. Man, I can't imagine how some of your systems sound (charlieboy's, Mr. C's ect..ect..). Granted they're listening rooms, not HT, but there is no law that says you can't have both. I guess knowing that there is something out there that's sooo much better acoustically than what I'm hearing from mine is what my biggest problem is. I'll never be happy.  :(
I'm not at all embarrassed about my system, I'd show it proud to any of you guys. Knowing all the while your probably thinking, "this sounds like hell. I can't wait to get back to MY room". But proud none the less.
I could stop on the room right now, never tweek another thing and be pretty happy with it. I'd continue to have friends/relatives over and show it off. BUT, I know myself, and will continue to tweek/complain/modify/spend money/bitch untill I'm blue in the face.

So John, as far as your comment about being ready to upgrade,.... I'm always ready (just not ready to move walls yet  ;)) ... you just keep those radical ideas coming. I'll build 'em...
Can't wait for you and bassboy to design that W.M.D. your planning.    I'd build it, as long as the drivers is'nt super high dollar.

Bob

EDIT- just proofread after posting, apparently the website censored me when I wrote "c0cktail", it replaced it with thingytail!? ... WTF? a totally innocent word censored by a website.  >:( (had to use a zero instead of an 'o' to get it to work that time.) Apparently "it" doesn't have a problem with me using other 4 letter words though.  ::)

for such a "popular" product, that clock has very little to back it up.... there's not even a white paper on it, I am not certain a passive device such as this could actually improve the sound in a room.  I would have a much easier time believing it if there was more to digest on the site than some reviews of questionable objectivity, along with the alway suspect comments from "customers"

The pebbles on the other hand, I can see those working, I always weigh my speakers down with something, helps the definition a little.  At the ame time, a sort of " phase plug" in corner helps to break up refractions in these problem areas.

Magic rings, stage expanders, isolation platforms, this may show my ignorance, but the site is either a snake-oil cart, or a shop out of AD&D...

and all of it at bargain basement prices!!!! I cant wait to give them my account number HAH

almost always skeptical
JJ

Bob,

I thought you were in St Louis.  I ran accross a Missouri audiophile group on Audio Circle and it was filled with nothing but "believers".  Since when did Missouri go through the gross transformation away from being The Show Me State.  If it sounds too good to be true, guess what, it is too good to be true.  

You want a jar of colorful rocks, fine buy a jar of colorful rocks.  You want to buy a digital travel alarm clock, buy one.  You want to separate you rig from vibration with weight and springs, fine, learn the math and do it right with the appropriate mass and springs, just don't go out and pay $25/ea for 25cent springs.  In any other business, vendors like that end up in jail for fraud, yet audio welcomes them with open arms.