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Discussion Starter · #1 ·
After doing REW sweeps of before the port and after, I realized I was tuned much lower than I thought. Thinking 990 cubic feet realizing 1003 cubic feet (closet door closed, opened it's more like 1040 cubic feet and 4Hz tuning) and from 9Hz to 5Hz, I can't have a title that I can't correct. I have never heard of anyone tuning to 5Hz before, or venting a 1000 plus cubic foot room. So I will leave the build log, post some final pics and REW snapshots in here, and of course now I will do some 5Hz and 6Hz sine waves and distortion plots.... as WinISD shows a VERY narrow SPL increase at tuning, so my 7Hz and 8Hz were out of the port passband giant peak.

Thank you Thomas for pointing it out!

[quote author=admin board=projects thread=1720 post=23531 time=1306460680][quote author=kryptonitewhite board=projects thread=1720 post=23527 time=1306442715]Final tuning appears to be 6.5Hz[/quote]

Unless the laws of physics have changed the tuning is between 9Hz-10Hz. And even that's doubtful because a Radio Shack SPL meter is not accurate test device.[/quote]

Actually, Thomas, if the laws of physics have NOT changed, I am tuned to 5.26Hz. And upon further inspection of the before/after ported plots, it looks like that is correct, more like 5-6Hz, kind sir.

room is 9'5" x 12'5" x 8'7" for 1003 cubic feet
port is 21.5 x 8.5 22"long



Thanks


 

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Discussion Starter · #2 ·
BTW, the reason I started with an 8Hz-9Hz guestimate and made it clear we would see, was I initially plotted with the manifold stopping at the subs and simply cutting the door panels out for ports which would have been 2 x 18.25"x8.25" ports 1.5" thick door, .75" MDF, about 2.25" port length. I decided to run the manifold sides all the way down for more strength to support all that weight and to keep the rear wave from simply canceling out the front wave with no port blockage. That left me with the option of putting 2 divider ports for the two insode port walls, making for 2 x 8.25"x18.25" ports 22" long for about a 7Hz-8Hz tune.

I decided on the final option, 1 giant port, 5Hz tune.
 

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Discussion Starter · #3 ·
THATS MORE LIKE IT! I did a 5.5Hz tone and the whole house wobbles, ceiling wobbles, fan, the paper in the port actually moves. 7Hz is way too high with this narrow of a peak. 95dB at 8%THD and 104dB @ 31% THD



 

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Discussion Starter · #5 ·
A few things that Ive been thinking, 1st is IB localization: be careful. Mine are centered right behind me so its not an issue, but if I had these to one side, it would drive me insane. I can clearly hear the mid/highs directionality. As for ULF, it comes at you from everywhere especially up from under you...no worries there.

People complaining about ports. Group delay. Coloration. Artifacts. I have aquired the opposite misconception. I hate the sound that does not come from the port. As soon as I cut that hole, it came alive. Musically more than anything. When I plugged the towers, it was bad. Not as noticeable because I should have braced the snot out of them.

Group delay? If thats the best you got...ok you can have it. That Bethoven track with cannon shots? Tom Danleys Fireworks? Let me tell you something about a kick in the chest yet that deep low soft fluffy gooey shock wave thats 4 times stronger in my room than in person....at the same time. Hard kick/punch/bang/POW! Mixed with that 7Hz onslought of viscous air. You don't hear the little cubes play the "bang" from 80Hz on up with the subs playing that 20Hz on up, then a split second later the ULF from the port hits you. The lightening in WOTWs does not show a flash then one mississippi two mississippi three mississipppp.... shock wave, like in real life. It's THERE.


So whatever on the ports sound bad gig.

The new enclosure shows 500ms!! Towers showed 103ms! Gimme a BREAK!

 

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Discussion Starter · #6 ·
So I've been silently waiting for feedback on the EQ, now I will just ask. Looks like it goes down to 20Hz, so can I EQ Down everything, efectively boosting sub20Hz material? WinISD shows a huge spike in excursion at 15Hz, so hopefully EQing down at 20Hz, 25Hz, ETC will bring down 15Hz but not 10Hz as much, and not 5Hz at all, therefor acting like a boost at 5Hz?


 

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Yes, Equalizing is equalizing!
Boosting in one area or cutting in another is basically the same thing, if done properly.

It sounds like you are pleased that you ripped out the old towers and went IB then ported.
You should be pleased as it looks like you put a lot of effort into it.
Happy listening,
Bill.
 

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I agree with you on the nit picking that goes on, Mr Andrew. Normal sounds contain a lot of distortion, reflections and what ever else may be present. I don't it's possible to stop it all.

I would like to hear that deep, mellow boom you describe. That's my kind of bass.

Good job on your project.
 

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Discussion Starter · #11 ·
Its incredible, Ive never experienced it with speakers before. Its just like the real thing. Did Virtual Thunderstorm at low volume this am to relax before getting up, even when it's not shaking you out of your bed it still moves you differently at different tones... the low crackle and rumble vs the high crack.
 

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Discussion Starter · #15 ·
author=chrisbee board=projects thread=1734 post=23547 time=1306529569]The criticism that are using a distinctly inadequate "test microphone" has already been flagged. REW's cal file for the Shack SPL meter runs out of steam an octave or more above your target frequencies. The correction factor as you sink below 10Hz is huge! It might reasonably be suggested that you are testing with a micrometer dangling from the end of a piece of string. (US: length of cord?)

The guys who calibrate microphones for a living might also argue that your tests have no validity. Do you have any friends (left) who might lend you a professionally calibrated microphone and preamp just long enough to confirm your results? ;)

As I gained a few more harsh critics recently such as yourself, I have gained a lot more fans. I am not saying Ricci, notnyt, or Bosso are fans by any means, but their posts alone make the coments of no longer having any friends roll off my back (unless maybe you meant my bass irritating neighbors? In which case I apologize)

At any rate youre not telling me anything I don't know. I know the mic rolls off. I know the results arent solid. You seem to not get that while you sit there and look over everything with a fine tooth comb, I dont care that much about specifics. It is all general to me.

This I know for fact: When I measured the towers then measured IB then measured current ported then measured windows sealed up then ceiling braced, I am NOT claiming the numbers themselves are accurate. I know for a fact that I gained below 10Hz going IB, then I gained below 10Hz by porting it, then I gained below 10Hz by boarding up the windows, then I gained below 10Hz by bracing the ceiling... how much exactly? IDK, but the invalid sub 10Hz testing is an indicator.

fine tooth comb away, knock yourself out!
 

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Discussion Starter · #17 ·
Ha! Your response to haters is very well done.

If you enjoy it and you're having fun, that's all that matters.
I'll tell ya what, Jason, haters are hard core... they have shaped my personality over the years. Yes, I am admiting that the forums have helped shape me as a person.

Thanks for the props! :)
 

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Discussion Starter · #18 ·
TBH I think I lost a touch of ULF on the fireworks, which correlates with the useless irrelevant REW sweeps that say I gained 7dB at 6.5Hz but lost 5dB at 8Hz.

ceiling partially braced cannon shots not fireworks Beethoven Wellingtons Victory Op 91

 

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Discussion Starter · #19 ·
After laughing with martiandancer316's analogies, I started a new Netflix movie... and BZZZ! Brandy looks at me, says "HONEY!" "There's a freight train coming! Wait for it..."

So the other day 1 screw and a bead of caulk didnt work, dropped 5 more screws.



I don't understand what you've built here. Could you provide a brief summary of what you've done?
Is the baffle a swinging door that you open to access another room on a daily basis or is this an unused room?

You've spent so much time and money on this project. I can appreciate you're going all the way on a wild & crazy idea.
Do you think you'll eventually come back to the "norm" and build a more typical home theater system?
hey CZ, I had the twin towers before. They were too "loud" from 10Hz-18Hz as they cause a rucous throughout the house but there was no actual sound to mask it. As well, I felt the 5Hz-9Hz material though it was at a much lower level, and I loved it even more than the 10Hz-18Hz material. Bosso and notnyt went on and on about how I was feeling the harmonics as it was below tuning so i said fine I'll tune to 5Hz instead and gladly accept a 10-15dB loss from 10Hz-18Hz in exchange for a better responce to 5Hz. As well, the towers had a huge loss in SPL due to flex, buzzed and rattled, and Brandy and Austin moved in. I never used the spare room before, but since they moved in we use it throughout the day. We had to climb up the bleechers, open it, and jump down...climb back up. Aceess to the front door and the HT room was tough.

So we cut the towers down, salvaged as much wood as we could, boarded up the HT room windows and SR windows, built a manifold, played, ported it, played, sealed windows better, played, braced the ceiling, playing.... :)

WOTWs has twice as much content now, 5Hz-9Hz material that was never present is now there. The 10Hz-18Hz probably did drop significantly, but since its all just as loud now or louder, i am guessing the 5Hz-9Hz more than makes up for it. There was a sceen at the beginning, semi trailors drive by, that used to make me wobble during the Aztek box with 2 walmart HTIAB plate amps that i lost with the towers. it's back. Hard to detect, but it is there. There was another sceen like that in HULK, I will test that later.

I really hope just 1 or 2 more people who have done extensive testing and commentary on their IBs is willing to seal things up and cut a pluggable repairable hole. I would bet an EP4000 they wouldnt go back.
 

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Discussion Starter · #20 ·
author=chrisbee board=projects thread=1734 post=23551 time=1306565228]Whoah there. :)

You told Thomas, in no uncertain terms, that you were tuned to two decimal places. So I questioned your measurement techniques. Fair enough? Apparently not.

Why publish your build here if you don't want the feedback you demanded of us? Does it all have to be back slapping praise?

I rather applaud your efforts to obtain serious welly in the sub 10hz department. I do appreciate your attempts to quantify your remarkable results.

You'll have to forgive me if I probe your methods and construction. I would do the same to anybody who turned up on the IB Cult forum and stomped all over the place in oversized boots. This is the IB specialist forum. Not the VLLT forum.

I would question everything about the project if I was doing it myself. Then I would test it to death and keep fixing the problems. I would tell everybody honestly about all my countless mistakes on my blog. And, hope that others were interested enough to tell me where I was going badly wrong. I'm not remotely an expert. I'm just a bumbling old fart who tries to learn from my mistakes made over half a century.

Mistakes and constructive criticism are the vital ingredients of any project. If it was all too easy everybody would think it wasn't worth doing. Or they would make all the same mistakes and get the same problems which you had forgotten to mention. Particularly if they tried to do it on the cheap.

Fortunately I don't have to seal up my own enclosure and make a port. You have done it for us. Interesting, but it needs much more work before we all cut more holes in our homes. If everybody on the planet tried for ULF we would need to go into space to get away from it!

I really think ULF is the province of those wealthy enough, or lucky enough, to have a large detached, rural home. One well away from any neighbours. To subject others to ULF for one's own amusement is a step too far. Our homes are not built for such stresses and nor are our those of our neighbours. I note you had to brace your own ceiling. Do you demand the same of your neighbour's home so you can play?

If somebody has a large concrete cellar with a concrete ceiling then it might be fun to experiment. In a normal home in a suburb it is not fair on those who do not share your enthusiasm. They get the vibrations but not the fun of watching films or listening to music.

This can be a serious form of torture because the neighbour is usually powerless to stop you. They fear revenge attacks from the mad moo with the subwoofer. This usually leads to chronic stress and eventually to depression. Noise pollution and noise nuisance are the major reasons people move home.

I'd have people who let their dogs bark all day taken right out of the genetic pool. No appeal. Anybody subjecting others to large doses of ULF deserve their everything coming to them. But, if your neighbours are selfish slobs and make a racket day and night then give it your best shot. You have nothing to lose except your own sanity. :-/


I really like that post :)

OK, so what things do you have on your mind to fix, tweak, test, modify? I'm listening :)

1st things 1st, How do i find out what is being passed next door? It's an apartment with atb least 4 units and no one has aid a thing except the one guy after he was over and I showed him the set up. I dont suppose theres much I can do other than keep it down. One thing I have noticed from long ago, though, was that it seems to only be the mid/high bass thats heard outside. I know usually the lower the frequency/longer the wavelength, the more it travels through and carries... but when I only had 2 18's, 1 per tower, it was all but dead outside. You could hear the windows rattle... of course, they are an enclosure wall and the room an enclosure..bandpass like you said... but you couldnt really hear the music outside. That was when I was flat to 20Hz then I had a HUGE spike from 10Hz-20Hz. Then I doubled up on drivers and my FR changed completely, I was flat to 30Hz then dropped off to 10Hz then sank like the Fitzgerald. That was when it got loud outside. Them when I went IB... true IB... it really got loud inside and out... from 30Hz up. It still seems now, even VLLT... I like that BTW and I am glad to have it instead of SLLT... that only the 30Hz on up is loud outside. The cannon shots, Im not so sure... its pretty loud outside but IDK if it was just the kick or if it was the ULF too.[/quote]
 
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