Bob,

Check my post above, in case you missed it.  If you want to think of ports like air brakes on a truck, then below tuning you have a busted air line.

[quote author=John in CR  link=1145573673/150#152 date=1148075627]Bob,

Check my post above, in case you missed it.  If you want to think of ports like air brakes on a truck, then below tuning you have a busted air line. [/quote]


this is an excellent analogy.  

Below a port's tuning in a normal ported box the Air behind the sub looses control over the sub's movements.   This is why You hear a klopping sound.  Below the port tuning, the ports no longer resist the Sub's motion so they flop around...

Nope, decreasing the diameter while keeping the same length raises the the tuning of the port.  Above that tuning everything is okay, but below you loose control.


If you really want to know why a port losses control below tuning I am sure someone can explain, but Its really not important the HOW or WHY.  Just know that it happens.

DAMMIT, just remembered, can't post at home.....  >:(

Talk to you all on Monday.

Bob

Bob,

Something to keep in mind is that a little tweaking is very easy and realistically starting from scratch is going to require one of 2 things, 4 times the box size (which will at most get you 6db more than optimizing what you have) OR two smaller boxes plus as much power as your drivers can handle and Linkwitz transform circuitry (which probably won't net much SPL gain).  You could spend over $300/driver and get some extreme excursion drivers, but again your 2 will about equal one of those, so you'd need 2 of them to add another 6-8db to your existing potential.

Getting into the low teens just isn't easy without numerous high excursion drivers, not when you're asking for 100db+ down there.  That's why I haven't built a super sub yet even though I have lots of drivers.

Well,.. had zero play time this weekend due to deck buliding, and the death of a good friends wife.  Too much death recently on this forum.

John, how about Dan Wiggins design you mentioned on page 3, reply #34. 110db @ 11hz to 40hz. I've got the amp, I think I've got the drivers (not sure if he's referring to DVC's or not?)

I've got the space,...I think for a 14cu'  box. That'd be less than 2'X2'X4' I believe. That seems small.

Now, I realize there's a gap from 40hz to my bottom of my current mains.
But I see an option...
"buck-up" and spend some money, Use Dan's plans for the content below 40hz, with new drivers, use HWK for the content from 40hz and up. Use existing 2 channel amp to feed both subs.
Would this be an acoustic mess? Crossover nightmare?

OR,... Build Dan's box, suffer with the hz gap until new main/surround can be built.

Whadya think big guy?

Bob

Ok, so I refered to post #66 on page 5. THAT is what I need to get lower hz, not nessesarily higher db.
Right?

I can accept the volume for the most part.  ???
But lower hz would be nice. I feel I'm not getting the most out of a movie if the soundtrack has material beyond what the equipment is capable of. The volume is the "cherry on top", as long as it has a decent punch. Your correct about teaching the youngsters bad audio habits. Not in the least, I'd hate to damage the frail little ears.
Bob

[quote author=John in CR  link=1145573673/165#165 date=1148333898]Bob,
I change my mind on a daily basis. [/quote]

Really I would not know what thats like. LOL.

Ok, John, I got some to spend some time in the cave. Preliminary "first" impression is the overall sound quality is improved (for HT use). bass is less boomy (in my room) more precise. Didn't go for SPL / drywall cracking bass. Happier with the 'kids listening level'.
However, when the kids arn't home and it's dad's turn with the controls, still lacking in the very low hz. I'm going to perform your tweeks when time allows.

Thanks again John.

Bob

As you go lower in frequency, Waves need to be much louder in order to sound equally as loud as normal thing we hear, human voices.  Meaning, a 20hz wave at 130db sounds as loud as a 4000hz wave 120 db.

Plus its really cool to have drywall cracking...

J, I have been working with drywall and painting all week with no end in sight and let me tell you, sir, there is nothing fun about cracked drywall.

[quote author=Bob in St. Louis  link=1145573673/165#171 date=1149026657]60, I'm not looking for the entire 2 hour movie being 130db. I do like my hearing just the way it is, and am not looking to start checking on the availability of audiophile grade hearing aids. My goal is for the LFE, and "superLFE" (to coin a phrase) to be just that 'little extra'. It may be slighlty unrealistic to have that spl with the hz I'm looking for (in real life). BUT, the theater going experience is'nt real life, in my book. The examples John and I have given as the "benchmarks" are: first person view inside an aquarium with a small child banging on the outside in Finding Nemo. The opening scene of Star Wars III when the fighters are flying amonst the big ships. And finally the cannon fights between the two 1820's era ships in Master and Commander (which, if memory serves, was YOUR recommendation in the other thread. Good movie too, thanks 60.) All of those examples are situations that most people in real life have never / will never be in. So there is no reference point. What does a mile long, 1,000,000 ton spaceship sound like, in real life, when it explodes?.... Well, nothing really if you want to be REALISTIC about it, since sound doesn't travel in space. But when I watch it on the big screen, I not only want to hear it, loud mind you, I want to feel it too.
We all know what the gental voice of a female vocalist sounds like when reproduced perfectly, or the pluck of a guitar string, and the whack of a kick drum. Even the slamming of a BMW door. I don't want to screw that up, BUT my main focus on this room is home theater first. (I know, I know, I'm on the wrong forum,... whatever. You guys have more audio intellegence than any other forum I've seen regarding home theater. AND nobody here is "better" than anybody else, one of my pet peeves.) So when I watch "TV", I have to turn the sub amp down just a hair, no big deal. But be warned,... if you come to my house to watch an action flick,.... by God, action is what your going to get!

Thanks,
Bob  ;) [/quote]

seems like a lot of work just to capture the few super-lfe moments you reference, there are very few movies i will watch twice, master and commander isnt 1 of them.but i accept we all have our own particular madness, and now i know where yours is bob.i however have 2500 watts on my sub in my car

60, have you ever been at a friend's house, or anywhere, really, and listened to a tune that you KNOW has low notes that your system can reproduce that theirs can't?

It's frustrating and when it happens to me I just ask them to please turn it off, silence is better.

The fact is that MOST people are missing the whole bottom third of their recorded material and they don't even know.  Most people wouldn't care if they did know.

WE CARE A LOT.  Once you realize you have been missing it you would rather throw out your recorded arts collection than live without it.  Try it, you'll see.

looking forward to pirates of the carribean 2

Spent some quality time just listening to the system from various souces this weekend, and am thinking the factory setup in my Chevy truck sounds better/sounds more accurate than my HT set up.  >:(
And this was at 30 miles per hour with both windows down.
I'm totally at a loss.

I realise my drivers arn't great quality (despite the MSRP) but I was happy for quite awile. Have I gotten used to them? (probably)   Am I board with them? (I think so)   Is my desire to build some of the good lookin' design YOU guys come up with making me "think" they're worse than they really are? (I'm very sure)    Have my tastes been refined by YOU GUYS? (guaranteed)    Have I "worn them out"? (doubt it)

Frustration with lack of knowledge and lack of funds is setting in. DIY is my only alternative. Unfortunatly being ignorant is a severe handicap.  :(

I havn't spent any money on another hobby I've got, thinking it may all go the way of Ebay soon. Problem is, it's also my sons hobby too.  ???  That one's more frustrating than this one. Shouldn't be that way.

ohhh what to do,  what to do.....

Bob

Bob,

Just get a flat screen LCD and DVD player for your truck, or forget the LCD and bring the projector and screen outside to do the drive-in thing.  You and the wifey probably aren't old enough to have been on a date to the drive-in.....Steam those windows up.

You have enough woofer for a good sub or pair of subs, but it sounds like you aren't happy with your mains and surrounds.  I hope you didn't have the mains going and set on "large" for your sub tests, because you could have blown something.  

If all equipment is ok, maybe you've just messed with the setup enough that things are out of whack.  Go through the receiver setup routine again.  Then listen to some music, stereo only, no sub.  If it sounds okay, proceed with the other channels.  Dial the sub in last.

With the sub, you may have to play around with the distance setting and XO point to blend it properly.  Keep in mind that the physical distance is only the starting point.  You've got group delay with bandpass alignments and ported alignments.  eg I'm using a ported sub temporarily while I decide on my long-term solution.  It's crossed in very low, since my mains go very low, and really only the port output comes into play.  Despite the 15ft physical distance, I found the best setting for the subwoofer distance is 30ft in order to blend seamlessly with my mains.

It's like any hobby that can be frustrating at times.  Don't lose hope, it can only get better, and it's a lot less frustrating than golf can be.

[quote author=John in CR  link=1145573673/180#182 date=1149516884] bring the projector and screen outside to do the drive-in thing. [/quote]

LOL, I like that John. I've thought about that believe it or not. It would be great for parties.

The surrounds have been set to small since the indroduction of the sub.

I've started over on the receiver set-up so many times, I can't count. I'm convinced any more improvement made in the audio department won't be coming from the receiver. It's got to be drivers (crappy) or room treatments. I've thought about making some panels to play with. The DIY of the panels is as easy as it can be, however the more time I spend looking at room treatment stuff, the more I find just how accurate of a science it is. I don't want to just 'put something together' and see what happens. Done that way too much already, as I mentioned in the last post.  ::)

So,... Should I stop on the HWK modding? Concentrate on drivers, treatments, or rob a bank and buy toys from "Steve D's toy room"?

I'd like to do one thing right the first time you know?

Bob (not on any anti-depressents either  :-X)

Don't worry about the whining, it's a frustrating game in the beginning.

Take it into perspective.  You read about this box that could make carpets levitate.  You thought, man, that's what I need.  You built it and found out that it truly does kick some butt but you find you are unhappy with the very low end.  This happens to everyone, I'm no exception, I just had a different box and it happened to me a long time ago.  Believe me, no one does ANYTHING right the first time.

So now you have a problem and people are firing solutions at you from all angles, people are disagreeing with the proposed solutions and you are getting confused and a bit ill at the thought of it all.

Taking the leap and building your own box was your first success, even if it was not the perfect box for your HT.  Listening to EVERYONE and sorting through the confusion and taking John's advice to heart is your second major success.  The guy clearly knows what he is doing.

So now you have a different situation but it's still not perfect.  You don't know why it isn't perfect, but realize this.  John provided the answer to the problem before you even told us what exactly was wrong.  Let me say again, the guy clearly knows what he is talking about.

The problem here is that the issues you are describing are generally not sub problems.  Punch, detail and accuracy of the overall system is defined by the mains, the sub and surrounds are just filler.  Please don't confuse this statement as meaning that the mains are the only thing that matters.

At this point, I would advise, as John has done already, that a good bit of tweaking is in order, and I'm not talking about construction.

First of all, strip the system down to the bare essentials.  Amp and mains only, leave everything else off.  Make sure the mains sound good before you continue.  Then add the surrounds and make sure they are doing their job.  Only at the end should you fire up the sub, taking into account that it may not be in the BEST spot.  You may have taken some time positioning it in the past but it is a different sub now and it's time to make sure.  If your listening spot is in a room null, the only cure is to move either sub or yourself or both.  As you move yourself or the sub, or both, towards the walls, the bass gets heavier.  Even moreso with the corners.

Understand that there is nothing wrong with your drivers, they may be inexpensive but they are performers.  Understand that it is pointless trying to recreate the car audio sound in the house.  You use different sources in car and home, and these different materials contain different frequencies.  Many may disagree, but I find it incredibly easy to make a car sound good but incredibly difficult to duplicate that sound in a room.  Especially a difficult room.  But you should know it can be done well.

Nobody said this was an easy game, especially when you are just beginning and making everything yourself.  But there is no guarantee that ready made equipment will sound any better in your room.  Everything needs tweaking, whether it involves speaker placement, level adjustments, listening position, room treatments, etc.  It doesn't ever end until you are happy with it all.  Which, by the way will never happen, you will always want more.

At this point you would be doing yourself a favor to make sure your mains are up the the job by themselves.  Do the car/room A/B test only with mains and see if the indoor clarity, punch and detail can keep up with the car.  If they can't, there is a problem with either the speakers, the placement of the speakers, or the room itself.  Go on from there, adding components back into the chain.  Once you have it sounding the best you can, download some mp3 sine sweeps to hear EXACTLY what your FR graph looks like.  You may have some big holes or overlaps at crossover points, sine sweep is the easiest way to find out and equalize without owning real measurement equipment.

At this point, the clomping sound of Xmech overextension is gone, consider this a victory.  But at the same time, remember that your system is just that - a system of many parts, each of which has their own job.  The whole job will never be done well if the separate parts do not work in unison.

Above all, remember that the "big dogs" usually have a system that is tuned to very specific frequencies for very specific purposes.  They choose the material you hear because not everything sounds good in their system.  They leave you with the impression that their system is perfect but you will never hear it's inadequacies, they won't let you.

Remember our friend Tapeworm, not happy with his HWK, stumbled across a big horn and it was perfect for him, certainly way louder, but we both know it isn't going to play well below 40 hz.  Sub 20 hz is a totally different ballgame  and is not nearly as easy.

So now, taken into perspective, you have chosen to try to recreate the HARDEST portion of the frequency spectrum, starting with very little knowledge and success, but you are slowly gaining both.  Give it time.

Bob,

I think you should hold off on the sub and decide on mains.  Then you'll know what range you need out of your sub.  So for now, leave the sub with the top off, making it a fairly compact, vented isobarik tuned to about 19hz.  You should be able to integrate it pretty well with your current mains and 105db without a rumble filter on Master and Commander isn't too shabby at all.  By the time you are ready to finalize your sub, some of us should have already tested these exotic TL type alignments we've been discussing.

The first place to start, as Bassboy mentioned, is your stereo mains.  Put your SPL meter to use and measure what you have.  Start a thread in speaker builders and include close-up picks of the drivers in the speakers you already have.  If you're lucky, the drivers are good quality, but are just implemented poorly.  That way you aren't starting from scratch.

so you butcherd your beautifully designed hwk and now it doesnt sound good............imagine ??? your vehicle is balanced because someone wasnt trying to make it play 18 hz at full volume, thay made it play reasonably flat across the board. perhaps its time to restore your hwk to its 'designers' spek and start to enjoy again? seriously bob, for now, forget chaseing 18hz@130db and get used to flat response and all the joy that brings....even to movies so what if you miss the occasional 18 hz rumble? you get EVERYTHING ELSE perfect.

Also, Bob never did report on the sub's SQ as it currently is.  All we heard was that it bottomed out at 105db playing cannon fire including very low frequencies.

Your chevy truck sounds better than your HT?
I have a suburban with cavernous rear quarters and really nice 6X9's I alse have some modded speakers in the dash with a center channel.
One pro high power deck and thats it. I was listening to organ ( church type) music on my trip this weekend.
It amazes me still. MY mobile version of the MG944. All I ever adjust is the imaging.
It is so well balanced overall that I will not mess with it. Its been the same for about 5 years.
this truck required the least work out of any vehicle I have ever had.

I can relate

The sensitivity rating by itself simply means the speaker is a bit less loud at any given power level.  That's all it means and you cannot make any guesses as to good or bad sound based on this spec alone.

Here's another bit to think about.  Any audiophile will tell you that the proper sub level is barely on at all.

Start by listening to the mains.  Slowly turn up the sub gain until you barely hear it making any sound.  Then turn it down a notch and that's your sub level.

I would not consider myself an audiophile and those levels are a bit too low for me, but try it and you might notice that the muddy sound your are describing is just way too much bass.

By the way, if your box is aligned exactly the way John told you, it should start getting strong around 40 hz  (on a downward sine sweep) and be satisfying down to at least 20 hz.  Are you sure it's exactly the way John told you?

60, I don't disagree with a single thing you said this time.  But you are neglecting a few points that we have made.

Not every sub is ideal for every purpose.  For example, the low tuned subs we are planning would absolutely suck where the HWK excells.  Even more to the point, your HWK measures completely different in the garden than it does in the corner of a small room.  Don't tell me it doesn't, unless you live in some other dimension.

The proposed other solutions (EBS ported and huge bandpass) are also tried and true options, they just weren't offered as plans by Steve.  The only product in the Decware lineup that is going to do what Bob wants is the imperial SO, that's just the way it is.

And furthering your alalogy of airplanes, a stealth bomber is not going to help you much if your need is really for a passenger jet.  (Notice I equated the HWK with a stealth bomber just to make you happy.)

By the way, I would encourage you to measure again.  Unless you have an Imperial SO, I doubt very much anything you have built is hitting 20 hz flat.  They just simply were not designed to do that.  What you just described in your HWK assessment is an F3 at 23 hz.  We are talking about F3's below 15, which may not seem to be an incredible difference until you look at the exponential nature of the FR line.  To be fair, I have only tried a WO and Imperial, both with inadequate drivers, but common sense tells you that you need bigger boxes and lower fs drivers to do 20 hz flat.  The only reason the Imperial SO is flat at 20 hz (as it is theoretically too small as well) is that Steve is ingenius in his designs, no one is disputing that at all.