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hz numbers on a 15" 2 driver (Read 13313 times)
Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #150 - 05/19/06 at 22:48:52
 
Not a bad idea 60.
I'll tweek some more based on John's advise. I have faith the man can help. He seems to be focused on bassboy and my projects fairly intently. He's got MUCH more experiance and knowledge than I. He's also got a home theater, so he might just have the edge on LFE's for soundtracks vs. music.
I don't mind tweeking, but like J_Rock said, it gets old after awhile. Especially when I thought I knew something about audio/video, and as it turns out, I know just slightly more than nothing. Tweeking is free. Being of "average income", I can't justify the purchace of the "just buy the high-dollar piece and be done with it" philosophy.  :(


Bob
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #151 - 05/19/06 at 22:53:47
 
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.
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #152 - 05/19/06 at 22:55:02
 
Without a doubt the HWK will go that low.  Bob would just need different drivers that sweep more air.  and to lengthen ports.  The reason the HWK is a club bass cab is the tuning of the chambers, the top chamber and the bottom chamber are tuned signifiacantly higher than one would tune to get the really deep bass LFE channels contain.

(I would say the exact tunings, but then someone could easily copy the HWK design.  So Lets just say its too high for Bob's Subs to go low.)

As far as having two subs~
I think subs should be used for the really low frequencies.  From 10 to 80Hz max.  Thats 3 octaves.  Not a lot to ask of a main to go down to 80Hz.  And 3 octaves isn't alot to ask of a subwoofer.  SO as long as the subwoofer design gives clean extension deep and distortion free up top, there should be no need for two subs.

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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #153 - 05/19/06 at 22:57:12
 
[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...

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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #154 - 05/19/06 at 23:05:31
 
[quote author=J_Rock  link=1145573673/150#154 date=1148075832]

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...

[/quote]


By that reasoning, wouldn't DEcreasing diameter of top port help regain cone control?

John, That's a lot to chew on. Didn't understand totally after reading the first time.  Signing off here at work, will re-read again in the am.

Bob  (THANKS ALL)
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« Last Edit: 05/19/06 at 23:07:41 by Bob »  
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #155 - 05/19/06 at 23:07:31
 
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.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #156 - 05/19/06 at 23:09:24
 
Knowing HOW or WHY would "help one master the outcome".

Remember, knowledge is power.   Grin

Bob
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« Last Edit: 05/19/06 at 23:09:48 by Bob »  
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #157 - 05/19/06 at 23:12:32
 
DAMMIT, just remembered, can't post at home.....  >:(

Talk to you all on Monday.

Bob
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #158 - 05/19/06 at 23:16:45
 
Well alright then.  The way I understand it:

A Ported box is extremely alike to a sealed enclosure.  Only difference is there is a hole in a ported box that is deep enough to support a standing wave.  The frequency at which this wave will stand is based on the length and diameter of the port.  Above the frequency of this port, the box acts just like a sealed enclosure.  As you get closer and closer to the tuning frequency, the port begins to resonate.  The resonace results in a boost in output near the tuning frequency of the port.  

Below the tuning of the port, things go haywire.  They do this because below the frequency, the waves are too long to form a standing wave, and so they pass in and out of the port without any restriction.  Since the hole in the box no longer resists the air flow, the air cannot control the subs movement from the lack of pressure behind the cone.  So the sub becomes "unloaded" and is esentially acting as if it were in free air.  

At low power this has very little effect on the sub, but at higher power, the sub quickly begins to move back and forth farther than it is intended to do so.  Eventually leading to the sub reaching it's mechanical limit of excursion.  In other words, the voicecoil starts slamming into something.

Hows that?
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #159 - 05/19/06 at 23:29:11
 
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.
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Adrian D.
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #160 - 05/20/06 at 17:37:05
 
i remember HBbass got pretty good results with the 10" version of the hwk, and steve's subs.
check the second page of the HWK support forum.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #161 - 05/22/06 at 11:54:52
 
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
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #162 - 05/22/06 at 19:27:28
 
Bob,

Sorry to hear about the problems.  It really sucks when others die.  On the bright side, when it's our turn hopefully it won't.

Dan said "more than 110db in-room".  It's essentially what you have now (with the top cap on) output-wise, but with deeper extension.  It's also exactly what I was talking about with HWKenstein by just adding the extension to your existing cab as previously outlined.  If you make the extension removeable, then you can have your cake and eat it too.
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #163 - 05/22/06 at 21:39:49
 
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
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« Last Edit: 05/22/06 at 22:16:32 by Bob »  
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #164 - 05/22/06 at 22:38:18
 
Bob,

That's the one and I think I had a post shortly after that talking about how to make it reversible.  Note that you will need to change the top port too to something close to Dan's recommendation.  The volume in that chamber net of the 3L for the driver and 4L or so for the port is a almost the size he recommended.

I think first though, try what you have with the top cap on.  Do your max test and SQ.  Experiment with lower tuning (longer ports) on each (4" in the case of the top one).  That higher tuning will get you higher max SPL than the big one and might just blend OK with your current speakers.  Even try a 10" longer bottom port for 15hz tuning, which may be low enough, although I think you'd be getting into high port noise territory with that long of a port.  

To check what 15hz tuning is like, you can also use your current bottom port length and mount the drivers in place of the top cap.  You wouldn't have the same excursion control (and max potential) that the 6th order BP (ported top and bottom) has, but it would definitely blend with your mains.  Easy conversion and easy change later to HWKenstein makes trying with the pretty box you already have make a lot of sense to me.  

If you want to go for the gusto, don't let me hold you back.  I've all but decided to give HWKenstein a go myself.  I just can't see building the 900L version of the Tower of Power that I've been discussing with Bassboy.  I might as well go sealed and use all my woofers if I'm going that big.  I change my mind on a daily basis.
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Gexter
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Re: hz numbers on a 15" 2 driver
Reply #165 - 05/23/06 at 04:59:35
 
[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.
Grin Undecided Undecided Undecided Undecided
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Bob
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #166 - 05/24/06 at 15:22:07
 
Ok, John, thanks. hurdle #1 is just getting back in the room.

Havn't spent much time in there recently. Well, except for American Idol with the wife.  :)

I'm not smart enough to change my mind. It spends enough time time trying to reinvent the wheel.  ;) I believe it was DD that discussed the uncontrolled dribble that his brain continues to spew forth. Kinda like that.

Bob
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Bob in St. Louis
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #167 - 05/30/06 at 15:45:47
 
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
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #168 - 05/30/06 at 21:34:28
 
[quote author=Bob in St. Louis  link=1145573673/165#168 date=1149000347] Didn't go for SPL / drywall cracking bass. [/quote]

why dyu want drywall cracking volume when your watching a movie?  i find the impact of correct tonality enough, a bmw door being shut or a body hitting the sidewalk from 3 floors accurately reproduced is more than satisfying.....2 mi? bmw door being shut @ 130 db would likely give me a heart attack....litterally.why the need for such excessive volume?
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #169 - 05/30/06 at 22:50:41
 
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...
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Bob in St. Louis
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #170 - 05/30/06 at 23:04:17
 
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  ;)
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bassboy
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #171 - 05/30/06 at 23:04:48
 
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.
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« Last Edit: 05/30/06 at 23:07:06 by bassboy »  
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J_Rock
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #172 - 05/30/06 at 23:15:44
 
LOL. Maybe not if you plan on repairing it...


I would leave it and people would ask, "Whys your ceiling cracked?"  

Then I would be happy to reply "My Subwoofer is loud.  And I made it"
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60ndown
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #173 - 05/31/06 at 00:25:42
 
[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 Wink
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #174 - 05/31/06 at 01:40:24
 
60,

Maybe you should change your nic to 30andUp.

Why play it?  It's on the recording for a reason, to be played.  Even most cinemas can't reproduce it properly.  We can get there relatively cheaply and it's fun to try.  I don't think anyone wants to boost what's on the track, just play it back exactly.  Explosions are loud, often uncomfortably loud for me in the audible region, but the subsonic stuff isn't.

I can see a lot more reason to have a sub that does 110+db at 10hz, than a car that will do 200mph.  I'd love to have both, so I'll start with the sub, since it's performance will get more use and it's more economical.
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #175 - 05/31/06 at 01:55:10
 
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.
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« Last Edit: 05/31/06 at 01:56:42 by bassboy »  
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Bob in St. Louis
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #176 - 05/31/06 at 12:23:33
 
60, The goal is to hear 100% of the artist intension. (ok, maybe slightly exagerated in the LFE's) I will watch quite a few movies more than once. Kinda like listening to the same CD/album multiple times. Granted your more "captured" when watching a movie versus having background music. It's much harder to see a movie traveling down the highway than listening to your tunes in a car.
You and I might possibly be cut from the same cloth, we both want quality, just slightly different situations.
Given 30 minutes alone (like when the rest of the family goes to the grocery store) I'll watch the first bit of Saving Private Ryan, battle sequence ect...
Just like the strictly audio guys here will sit and listen to a couple tracks of an album/CD, and not nessesarily the entire disc. I'm perfectly happy seeing "bits" of movies (at volume of course  ;D). Sure, given enough time I'd rather see the whole thing, and make a event out of it. It's my drug, my escape from reality for awhile. I'm sure everybody understands that.

Bassboy, I completely understand what your saying about asking others to turn it down. Nothing worse than listening to someone elses tunes at high volumes when it sounds like crap (and they're grinning because they think it's cool  ::))

J_Rock, I've though about having SLIGHT drywall damage thinking it's cool and telling others, "yea that's because of the sub I built", and not fixing it. But I'd rather not have any cracks if the truth be told.

Bob
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60ndown
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #177 - 05/31/06 at 12:56:53
 
looking forward to pirates of the carribean 2 Grin
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« Last Edit: 05/31/06 at 12:57:05 by 60ndown »  
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Bob in St. Louis
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #178 - 05/31/06 at 12:59:15
 
YES!
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Bob in St. Louis
Ex Member



Re: hz numbers on a 15" 2 driver
Reply #179 - 06/05/06 at 13:23:00
 
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

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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #180 - 06/05/06 at 13:46:29
 
Bob, hang in there.  I've been interested in the subject for 20 years.  It's only the last 2 that have brought internet and SERIOUS learning.  If you asked me to build a box 3 years ago, it would have been manufacturer's spec ported because that's the only thing I knew.  At this point, I can't imagine ever building a ported box again (unless it's EBS).

All these ideas you are getting are going to start making a lot of sense and become second nature.

Sometimes it's ok to put a project on the back burner for awhile and try something else, but don't give up on it.

Remember that when tuning a box below resonance costs efficiency.  It's all a trade off - if it's tuned high it's loud but bottoms out with low notes.  If it's tuned low it's quieter but handles low material much better.

What exactly is wrong with your SQ?  Does it actually sound bad or just not loud enough?  Are the Xmech (excursion) problems gone?  Does it sound ok at lower volumes, and if so, how much power are you trying to cram in there?

Keep at it, it's a lifelong struggle but you have to admit, it's fun.
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #181 - 06/05/06 at 15:14:44
 
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.
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #182 - 06/05/06 at 15:17:23
 
[quote author=bassboy  link=1145573673/180#181 date=1149511589]What exactly is wrong with your SQ?  Does it actually sound bad or just not loud enough?  Are the Xmech (excursion) problems gone?  Does it sound ok at lower volumes, and if so, how much power are you trying to cram in there? [/quote]

Well bassboy, I'm may not be enough of an 'audiophile' to accurately describe the SQ. But it seems to lack the accuracy, the punch, the.... DETAIL.  It's not as "crystal" as my truck is. I've sat in the garage with the engine off, windows up (best case senario) listening to a few choice tracks, then took the CD to the HT room for an A/B comparison. The truck (factory system) is clean, clear, accurate, precise, a "pin drop" type of thing, know what I mean? The HT room seems less of all. Hard for me to describe. It may be a room treatment issue?? It's kinda 'muddy', not 'skilled' enough to determine if it's crappy drivers, or room treatments. I've though about playing with absorbers, but I've played with too many things (and spent money) that havn't worked out.
Am I bitching?

ok, continuing to answer your questions. It's not an excursion issue anymore, I've learned to turn the sub amp down when  certian material is playing. (Still want to do John's mods to the HWK)
Actually, I've learned to turn everything down. I was trying to make my system "run with the big dogs" when it apparently wasn't made to.  ::) So instead of analizing db's and super low hz, I'm more on SQ.

I've got three 'modes' I use the room. #1 When everyone's sleeping in the am I'll play games at volumes almost too low to analize. #2 Movie time with the family, no obscene volume here either, sometimes hard to analize SQ with the kids in the room. #3 Bob's time when everyone is gone, guess what happens to the volume/amp gain then. It almost sounds better watching a movie at too high of volume than it does at 'resonable' levels. I'm usually "going for the gold" then, Like I'm spl drag racing. Ok, I've learned my lesson. I've quit doing that (don't want to blow something up) So now I'm listening at levels (music and movies) that, may be on the high side by some folks standard, they arn't "stupid high". But it seems I'm loosing material at these levels.

hmmph.

Bob
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #183 - 06/05/06 at 15:49:18
 
[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)
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« Last Edit: 06/05/06 at 15:56:12 by Bob »  
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #184 - 06/05/06 at 17:58:59
 
So now bassboy is spewing forth more news, adding to the doubt already planted in my head.  ??? Over in the 'Help me HT' thread about amps dropping off below 30hz. Dude your killing me Cry I know just enough to doubt everthing I own.)
Dammit, life in my own little world was sooo happy when I didn't know shit!

Ignorance IS bliss.

All you guys are great.  ;D  Thanks for the words of encouragement, and all the help. It's greatly appreshiated [sp].

Hang with me, I'll stop whining.  :)
Bob
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #185 - 06/05/06 at 18:51:15
 
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.
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DirtDawg
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Re: hz numbers on a 15" 2 driver
Reply #186 - 06/05/06 at 19:05:25
 
[quote author=Bob in St. Louis  link=1145573673/180#185 date=1149526739]..... sooo happy when I didn't know shit!

Ignorance IS bliss.

[/quote]
Ignorance is a blister.

Cure:
Loads of surface area, low tuned EBS with enormous port, too much power. Bi-amp to second cab if you need bass, in addition to sub bass.
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« Last Edit: 06/05/06 at 19:10:59 by DirtDawg »  
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #187 - 06/05/06 at 19:15:44
 
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.
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #188 - 06/05/06 at 22:54:33
 
Guys Thank You. I've managed to have a pretty bad day at work (after all of my spewing) and you have brightened it. Having some focus and a goal is mui importante' (that's for you John) but having a few intellegent individuals guiding you is invalueable. Priceless.

bassboy, John - I'll listen to just 2 front mains to get an idea of SQ to ensure I have'nt misadjusted something. However, if memory serves these are 88db drivers. I have enough knowledge to know that these are turds about to be polished.

If you think, based on that number alone, I've got a shot at a successful "main mod" than I'll proceed. If need be, I'll find all of the specs. No, they don't have T/S numbers, just the basics.
If we go with the mods of my existing drivers, it sounds like my steps are these:

#1 isolate (disconnect) ALL drivers but one main, run sweeps at three feet from cone (mains are an MT arangement). I can't measure wattage, so I'll "pick a numeric referance point" on the display of the H/K receiver. Should I use stepped sweeps and record db's at given hz intervals? If so, what range and what interval to give an intellegent test?

#2 My next step is to take an enclosures apart, and find out what I've got driver wise. I'll post pics in the builders forum. Damn, I really need a digital camera.  ::) Gotta wait to 'burn a roll of film', then develop.  :'(

bassboy, that reply you just posted should be a 'sticky' at the beginning of the General Audio forum.  ;D That was excellent.

Bob
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #189 - 06/06/06 at 00:34:07
 
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 Grin so what if you miss the occasional 18 hz rumble? you get EVERYTHING ELSE perfect.
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #190 - 06/06/06 at 02:09:36
 
Actually, the reason I recommended sine sweeps is because you don't need any measurements but your ears.  Start at 20 kz and it's a continuous signal down to 20 hz.  It should be equal volume all the way down, no peaks or dips.  If you use the computer to play the mp3 sweep, you can roughly estimate where you are on the FR line by the moving bar in the media player.  That's about all sine sweeps are good for, as they certainly will not tell you if the speaker is musical, even if the FR is flat.  If you want to go to the trouble of measuring specific frequencies with a meter, go ahead, but I trust my ears to tell me what's going on.  They don't have to measured one at a time either.  Sit in your listening position and play the sweep played by both mains.  If the signal is the same volume top to bottom, that's all you need.

Then it's time to measure musicality, which is entirely your preference.  This can only be done with your favorite tunes.  Come back at us with impressions - good, bad, coherent, muddy, etc.  Compare it to the truck, if you want, just about all of us know what a GM truck sounds like.

Never mind the main's driver specs, they don't make any difference.  The box is already built, all you have to do is make sure it pleases you.  Low sensitivity drivers are not bad, just a bit quieter.

And finally, 60, no one is disputing the fact that the HWK is a great design.  But Bob wants a home theatre sub.  So do I.  The HWK has a place, and will stomp the competition if it's used for what it was meant for.  But it is not an extremely low tuned HT sub, that's just the way it is.  Bob probably would have been further ahead to build EBS ported or huge bandpass or maybe even an Imp SO in the first place, but he didn't know.  We all agree with the fact that the HWK is a great design, ok?  But we strongly disagree with the idea that reproducing the lowest notes on our recordings (mainly movies) is not worth it.
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John in CR
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Re: hz numbers on a 15" 2 driver
Reply #191 - 06/06/06 at 03:13:07
 
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.
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #192 - 06/06/06 at 13:19:49
 
60, In the eyes of many, sure it's butchered. It doesn't sound good your correct. The reason it's modified is that in MY room, with MY situation, with MY equipment, it didn't sound good in the first place so I had nothing to loose. I'm not enough of a 'professional' to make any concrete statements, BUT it sounds like the famous "one note wonder" everyone talks about. It has been pushed and shoved, flipped, leaned, tilted, and twisted in so many configurations in the room trying to find proper placement it's not funny anymore. I actually thought about installing casters on the damn thing to ease in moving it.

As far as my truck being resonably flat across the board, it may be. But the board ends at several hundred hz too. It doesn't have to work too hard.

I've put 18hz@130db on hold. Not sure it's obtainable on a budget. How about 18hz@105db? Resonable enough for a workin' class man? I think I'd be happy with that.

As far as missing the 18hz rumble and everything else being perfect, well.... I don't think I've got much below, hmmm 30, 40hz?

You CAN'T tell me you have never been unsatisfied with your equipment. You've never tweeked? EVER? If you just buy and install it, then your either easily impressed or have enough money to get what 'fits the bill' the first time.
BTW, I noticed your signature a few posts back, not to be vain, but was that for me? ???
Thanks for the multiple boots to the testicles 60. Smiley How's that landscape project coming along? You didn't have any critters build nests in the ports of the HWK being outside did you? hehe

bassboy, I've got the sweeps, no problem there. Either need to 'burn' a CD, or run some wires from the PC, to the system to hear them. As far as the "quieter" comment about low sensitivity drivers, you mean there is no quality difference (in sound) between a 88db and a 95db driver? (tube rigs aside of course, since I'm SS)
You hit the nail on the head in your last paragraph about using the HWK for it's intended purpose.

I listened to several tracks last night with no sub. All four "smooth" jazz instrumentals that were clean, simple, clear tunes, no finger smoken' guitar rifs. Volume was a '5' on a scale to 10. (And I don't mean 5 on the volume knob) Nice and easy just loud enough to hear all the nuances. With no sub, it sounded fairly clean and concise. The soundstage is excellent (no thanks to the drivers, I give all the credit to the receiver for that) I was pointing out to the wife the subtle aspects of the tunes that she never heard before (getting her interested in SQ, trying to raise the WAF. It's working I think  ;D)

Let me back up a bit. I established early on in my tenure hear that my CD/DVD source is an XBox 360. (I'm sure most of you just leaned back in your chair, eyes rolling to the ceiling)
The songs we heard last night were either 'burnt' cd's of jazz, or songs that were originally from a 'factory' cd, stored to the hard drive of the 360. I've found no difference in SQ from a 'factory' cd playing on the unit, compared to the same song stored on the hard drive.
Now it seems to me that all of the clues add up to a bass problem. The kids were sleeping last night when the wife and I were listening, so I had no chance to let the system 'stretch it's legs' with the sub out of the mix. But it seems that the lower content is mudding things up. Now I see a few posibilities; crossover problem, sub itself (not being a good match with my room) room treatments, or finally, something in my rack doesn't like the LFE's?

hmmmm  ???

Bob
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Gex
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Re: hz numbers on a 15" 2 driver
Reply #193 - 06/06/06 at 15:15:08
 
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
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #194 - 06/06/06 at 15:21:58
 
And it's a factory system. 5 years old with 90k on the odometer.  ::)
Sitting in the sun, cold. Worst case senario for a driver. Imagine you were at 5`F on a cold winter morning and some A-hole cranks your knob to 7, expecting your best when your frozen.  >:(
And some how manages to sound great. (granted not audiophile, but great for an O.E. set-up anyway)

Bob
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #195 - 06/06/06 at 16:39:09
 
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.
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Bob in St. Louis
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Re: hz numbers on a 15" 2 driver
Reply #196 - 06/06/06 at 16:48:51
 
Thanks bassboy, and here I thought I'd make it through the day without learning anything!  :)

Bob
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #197 - 06/06/06 at 17:54:08
 
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?
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« Last Edit: 06/06/06 at 17:55:28 by bassboy »  
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60ndown
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Re: hz numbers on a 15" 2 driver
Reply #198 - 06/06/06 at 19:35:50
 
the thing is for me fellas, that of everyone that posts here i believe steve deckert is the most knowledgable. he has been designing and building for a long time (and not part time), i have built several of his designs (not modded) and they all did exactly what he said they would , basically flat to 20 hz and excellent sq, i have a test disk and there is very little, if any drop off until about 23hz? in my hwk, i have had it in many different positions (includeing the garden Smiley) and all it does is produce 'gobs' of great bass. i know from your posts that you all understand audio better than me, so i cant argue any specific points, but lets say this, if i had to build an aeroplane and actuallyfly in it), i wouldnt try to modd one, i would build a tried and trusted desighn that had carried many people many miles many times, and returned them to ground safely. which i believe is exactly what steve offers in his plans Wink ....except obviously his subs dont fly, but apparently they can 'levitate' rugs!
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« Last Edit: 06/06/06 at 19:36:26 by 60ndown »  
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bassboy
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Re: hz numbers on a 15" 2 driver
Reply #199 - 06/06/06 at 19:57:50
 
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.
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