Would an IB be an upgrade for me?

Discussion in 'Archived Threads 2001-2004' started by David Giles, Mar 21, 2002.

  1. David Giles

    David Giles Stunt Coordinator

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    Hey guys. I've got a dual SVS 16-46CS+ package in a relatively small room (roughly 16*10*9 - about 1500 cu ft). In this small room, they're very impressive, and easily reach reference. So you may wonder why I'm asking about IB's. I guess I'm just itching for a project. When I bought the SVS's, I strongly considered building my own sonotube, but finally decided to just buy the SVS's. At the time I really didn't know anything about IB's. Well, I've got an attic, or possibly a closet that I can mount the IB in, and I'm thinking maybe a couple of Tempests. Based on some of the testimonials, the IB seems to be the ultimate in sound quality, as well as output. If any of you have heard SVS's, do you think I'd hear any appreciable sound quality difference between the IB and the dual SVS's? Assuming I used the same Samson S1000 amp (500 w/channel) that I use to power the SVS's, do you think the IB would match (or possibly outgun?) the dual SVS's in sheer output, especially down to the SVS's tuning of 16 Hz?

    I'm very happy with the SVS's, but if the IB had an appreciable edge in quality, and at least matched the SVS's in output, then I'd consider it a worthy project. If the IB won out, I could EASILY sell the SVS's and still have money in my pocket after building the IB. If I ended up liking the SVS's better, I could probably sell the fully built IB for at least the cost of the drivers, and only lose a little on the materials.

    I've read through the "Cult" forum, and posted these thoughts/questions there as well. But that forum isn't too active, and there seems to be a ton of knowledge here.

    What do you guys think? ANY opinions or thoughts would be greatly appreciated.

    Thanks!

    David
     
  2. Andrew Pratt

    Andrew Pratt Producer

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    I'll be building mine in a couple of weeks and you're right from all that I've read IB subs can offer the best sounding bass there is.
     
  3. Dustin B

    Dustin B Producer

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    A pair of Tempest will easily out displace a pair of CS+ subs. So output wise there is definately the potential for more. Dual Tempests are just over 5L, and dual CS+ are around 3.6L (if my guesstimates from reports on what SVS drivers are similar to and the % claims of Ron+Tom).

    IBs are supposed to be the ultimate in bass quality when the correct driver is used (I don't know for sure, but I'll take ThomasW, Rich Kraus and Mike Knapps' word for it). And buy all accounts the Tempest is a perfect canidate. So it should sound significantly better as well (assuming good placment and some eqing).

    Power wise, the S1000 will be way way more than you need. A pair of Tempests in an IB config will be very efficient. Rich Kraus has has excellent results from 250W total for a pair of Tempests in an IB config.
     
  4. David Giles

    David Giles Stunt Coordinator

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    Andrew:

    Please let me know your impressions as soon as you get it finished. I wouldn't be able to start any sooner than that anyway.

    Dustin:

    Thanks for the info. It sounds like I'd be pleased with the IB. You didn't say anything about low-end extension though. Would you expect the dual Tempest IB to extend as low or lower than the SVS's?

    Thanks,

    David
     
  5. Dustin B

    Dustin B Producer

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    Given the Fs of the Tempest I would imagine an IB Tempest could take a 20-39 for extension. The dual 16-46CS+ might have a little more output around 16hz.

    But also remember that a IB is just a sealed sub with a really really big box. Sealed subs have a 2nd order (12dB/octave) roll off while a ported sub has, I think it's a 4th order (24dB/octave) roll off below tuning.

    So with some room gain and eqing a dual Tempest IB would easily be flat to well below what you can hear. In fact it could very well have usable output to below 10hz.
     
  6. David Giles

    David Giles Stunt Coordinator

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  7. Rick Guynn

    Rick Guynn Second Unit

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  8. David Giles

    David Giles Stunt Coordinator

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    Thanks Rick!

    It looks like Rich didn't boost the
     
  9. David Giles

    David Giles Stunt Coordinator

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    I've been talking back and forth with ThomasW (the IB expert over at the "Cult"), and he's been VERY helpful. I thought I'd ask you guys some of the questions also to get multiple perspectives. Some of these would only apply to those of you who have heard an IB, but others are probably general enough that any of you sub experts could answer.
    If I do this thing, I'll probably mount the IB in the attic (since I think the closet is too small). One concern I have is the amount of sound you get in the rest of the house. My house is a 70 year old solid built 2,000 sq ft brick house. Right now when I listen to movies (pretty darn loud), the low stuff can be heard a little bit on the other side of the house in the master bedroom, but it's not too bothersome. For anybody who's had any experience with an IB, just how bad is the bass throughout the rest of the house? Would the amount of bass heard in other rooms be significantly worse than with my dual SVS's? Convincing my wife to let me cut a hole in the ceiling will put enough strain on our relationship, but if when it's all done she can't hear herself think in other parts of the house, I'll really be in trouble [​IMG]
    The IB would be in the ceiling above the main speakers, and assuming there isn't any structural problem, I would center it between them. That should be acceptable - soundwise, right?
    Also, my attic is your typical old wooden frame attic with blown-in insulation. I would consider it a worse environment than the typical car (much dustier, but probably no worse on heat). Do you think the drivers could withstand years of dust buildup?
    Is there ANY chance of fire from the IB? My house would probably go up like kindling, especially if a fire started in the attic and got established before I realized it.
    Thanks in advance!
    David
     
  10. kevin_u

    kevin_u Agent

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    David,

    By a mile my 4-Tempest IB is the best bass I've heard. The bass is effortless, has excellent pitch definition and goes way low. Now that I got that out of the way, on to your questions.

    Yes, the IB shakes our 1700 sq ft ranch house. So you might get in trouble with the wife, but at least she won't have to look at those big tube things.

    Before mounting the manifold, I took Thomas W's advice and took measurements from various locations to determine the best spot using my existing sub. Centered between the mains worked best in my room.

    The room that serves as my box is my dusty woodshop. Time will tell if the dust is a problem, I seriously doubt it will be a problem.

    As far as fire issue, don't know. Well even if I did know, I wouldn't answer without consulting my lawyer. Just kidding around. Anything is possible, your amp could pass DC and start the voice coils on fire.

    And yes, Thomas is the man for IB info. A friend of mine, John, owns a AV shop, he is been working on a horn project with the help of PASS Labs. I've told John about my IB, which in turn he's talked to the guys at PASS Labs about IB's. I recently visited John, he had a e-mail he wanted to show me, it was a e-mail containing Thomas's Twelve Dancing Shiva's IB project someone from PASS Labs had sent him. Pretty cool!

    Kevin
     
  11. Rich Kraus

    Rich Kraus Stunt Coordinator

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    hi guys, well you know how i feel about my IB's performance (wouldnt trade it [​IMG] ) so i wont go to far there.
    i played with boosting it at 20 hz, but ended up not using that filter. the AVA250 im using still has its 18hz filter intact, so i just let it roll off there. depending on what "correction chart" you believe for the trusty RS db meter im between -2 db and +6 db @ 18hz.
    as far as home shaking is concerned, in my case its not too bad. actually its sort of fun finding the things that resonate in odd places (my garage door, and the vent in the back bathroom are good examples here.) remember though that since the HT/living room is an addition, ive got concrete block on three of four walls. even when its PLENTY loud inside, the rumble outside is pretty tame. also, dont think house shaking is strictly an IB thing. ive been over at Mikes when the water heater was on boil and things were shaking pretty nice in the garage.
    dust? what dust? i got up in the attic after about a year had passed since the install, and the backs of the cones were pretty much clean. im guessing that the constant vibration must keep dust buildup to a minimum.
    my big concern was that some rodent would chew something up, as we get them from time to time. problem solved by keeping a block of tasty rat kill stuff near the IB. ive found it chewed, and the IB has not been.
    as for power, id use a bigger amp if my install desires didnt dictate a plate amp. now i dont want bigger enough to upgrade as theres not enough benifit to justify it. im just noting that a nice stout amp wouldnt be a bad thing for the extra headrom. (i get clipping before bottoming, but i never listen this loud so it dosnt matter)
    anyway IB=good
     
  12. Dustin B

    Dustin B Producer

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    Wasn't too long ago you had just decided to build that thing Kevin. When we gonna see some pics?
     
  13. David Giles

    David Giles Stunt Coordinator

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    Kevin

    Thanks for the comments. I do have a few questions for you. Roughly how large (cubic feet) is the room your IB serves? Is it a closed off room or does it have openings into other rooms? How much wattage are you using with your 4-Tempest IB?

    I know it’s difficult to quantify the amount of sound or “shaking” going on in the rest of the house, but I’m just trying to decide if I’ll have a war on my hands with this thing (and that’s assuming I win the ‘cut a hole in the ceiling’ war). I’m sure you all know the SVS’s, by reputation at least, and they shake the house pretty well themselves. But I can safely play them at any level I can stand while my wife is in the master bedroom on the other side of the house, without causing major marital stress. It’s not that she can’t hear them playing in there. But she’s not really that sound sensitive, and doesn’t mind hearing them a little. On the other hand, if with an IB, she couldn’t talk on the phone in the master bedroom, without having to yell, then that would be a problem. And if she couldn’t read because the book in her hands was vibrating uncontrollably, then that also might be a problem. Rich says his isn’t too bad, but that his room is somewhat isolated from the rest of the house structure. Do you have any further comments on this (like how bad is the shaking in YOUR house, compared to your previous sub)?

    Oh and like Dustin mentioned, I'd love to see some pics!

    Rich:

    Thanks for your comments too. If I do this thing, I’ll be using the Samson 500-watt-per-channel amp I currently use for the SVS’s, so that should be plenty stout enough.

    I like the rat-bait idea. I hadn’t thought about that, but it could be a potential problem in the attic, so I’d definitely go with that.

    As far as dust, I thought I might build a really simple little “roof” over the IB just to cut down on the amount of dust settling down onto it. It’d still be open on all sides to the attic, with just a piece of plywood up over the IB held up by 1*4’s? Does anybody think that would be necessary (or useful) at all?

    To everybody in general:

    I like the idea of testing my IB location by moving my current subs to that spot first. But my IB will be installed in a 10 ft. ceiling (hopefully centered between the mains). Does “vertical position” have much of an effect on response? In other words, if my current sub sounds good in a particular position on the floor, will the IB have the same response mounted in the ceiling directly above that spot?

    David
     
  14. David Giles

    David Giles Stunt Coordinator

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    In another interesting thread, Bob Ahlberg was discussing IB-like installations in cars. Here’s his text:

     
  15. kevin_u

    kevin_u Agent

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    David,

    Our HT is in the basement, somewhat isolated. The HT is 15x8x22, the "box" room is roughly the same size. The house starts vibrating at about 85db when playing a source with low fz's. I typically listen to music at about 80db, which is not a problem. Watching a movie like U571 at reference level will excite the entire house.

    I 1st used a 200 watt Adcom GFA555, more than enough power. I'm now using a NHT SA-3 sub amp, 250 watts. I changed to my NHT because I wasn't happy using the 80hz x-over in my processor, I wanted something lower. The NHT has a adjustable x-over which I have set at 55hz. I have the woofers wired so that the amp is looking at a 4ohm load.

    My previous sub was a Wilson WHOW II. I bought a used driver (JBL 2241H) and the mating Wilson x-over when I worked at a AV shop. Built a cabinet for it. It was a nice sub, very fast and detailed, but didn't go much below 22hz. This is my 1st experience with a sub that will play down to 10hz. The WHOW played insanely loud, but didn't excite the house like the IB.

    Another way to test for the best location is to place your current sub at your listening position, then climb up on a ladder and take measurements at various places.

    Points 1 & 3.

    I wouldn't be concerned with either. The IB is such an efficient system, even at high levels the drivers are not moving much. If I remeber correctly, Thomas is using a 150 watt pro amp on his 12 Shiva's. Maybe in a ported box you could get a few more db's, I'm more then willing to give up a few db's for the quality of bass. I might take some heat for this, but it kills me when I read about guys hitting 120db or more from their subs. What do those guys have for mains? They have to be distorting like mad at those levels.

    Dustin,

    I promise, pictures will be soon. I'm building my brother-n-law a IB, when he picks it up I'll snap some shots of my IB with his camera.

    Kevin
     
  16. Jack Gilvey

    Jack Gilvey Producer

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  17. kevin_u

    kevin_u Agent

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    Jack,

    Good explanation.

    At a reasonably loud level my drivers don't seem to be moving excessively. The advantage of using 4 drivers?

    Kevin
     
  18. Jack Gilvey

    Jack Gilvey Producer

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