[versus rider]

So a complete change of direction, out go the horns/OB bass and ribbons and in is mark levinsons red rose two way stand mounts. Now I set an average spl of 80db and then ran test tones and have 80db at 50hz, bravo red rose, as they claim 50hz in room response from a 100hz to 20Khz speaker and what a fantastic speaker it is. So I have a much simpler set up with just one amp, 300B, source and speakers. But I don't want too simple so thinking two subs but only up to 50hz. What subs will go low, ie 10hz and only need to go to 50hz. Alternatively I would prefer to diy them, any thoughts appreciated

[jk@home]

Infinite baffles will go that low, but you have to commit to a permanent installation. I have a couple of ceiling mounted IB manifolds (total 4-15" drivers) in my listening room, which I now need to match with a pair of KEF LS50 two ways. Waiting for the KEFs to break in before I do any serious measuring and adjusting. They did great with the Magnepan MMGs that the KEFs replaced.

See the Cult of the Infinitely Baffled forum for more info.

[JohnR]

Getting an accurate measurement at 10 Hz is probably harder than making subs that "go to" 10 Hz

The real question is how much output do you need at 10 Hz?

[versus rider]

Not much john, a 10' x 10' room with red rose rosebud II stand mounts easily driven to 80 db by a 300B just ticking over. Infinite baffle is possible but I would need to insulate the loft  area due to the cold winter.  Any plans of those IB's?

[Letitroll98]

Getting an accurate measurement at 10 Hz is probably harder than making subs that "go to" 10 Hz

The real question is how much output do you need at 10 Hz?

I agree, I have corrections for my RadioShack meter down to 20 Hz, but can't imagine what musical program material besides record warps are reproduced down at 10 Hz.  Thunder?  I guess there's some special effects stuff to reproduce there.  And in a 10'x10' room, I'd think it pretty hard to get 10 Hz with any volume.  But a noble goal regardless, I'd be interested in seeing any solutions for that.

At the other end, I can't see a problem with either and active or passive cutoff at 50 Hz.  That was the frequency I used with both my Maggies and PSBs, it was pretty easy to integrate either speakers at that point, albeit with a either a 10" driver or two 7" drivers, both flat to only an in room measured 27 Hz.   

[jk@home]

Any plans of those IB's?

Go here:

http://ibsubwoofers.proboards.com/

Thomas W  has done a great job covering all the basics. Register as a member (it's free) and then you can access the "My Projects" section, to see individual examples. On page 4 is "johnvb's IB project", the above install.

[JLM]

A 10' x 10' room?  Expect crazy amounts of standing waves.  Don't know how much of a room acoustics solution is possible. I'd contact one of the known experts.

If intrigued with I.B. Check out the Cult of the Infinitely Baffled website.

[brj]

I agree, I have corrections for my RadioShack meter down to 20 Hz, but can't imagine what musical program material besides record warps are reproduced down at 10 Hz.  Thunder?  I guess there's some special effects stuff to reproduce there.

Wiki:

The lowest note that a pipe organ can sound (with a true pipe) is C-1 (or CCCCC), which is 8 Hz, not visible on this chart. However, if acoustic combination (a note and its fifth) counts, the lowest note is C-2 (CCCCCC), which is 4 Hz.

Of course, not all organs play that low...

Interesting link on previously mentioned IB website:

http://ibsubwoofer.blogspot.com/2010/02/reproducing-biggest-organ-pipes.html

[versus rider]

Funnily enough I joined that forum before seeing your link. Will spend some time there gleaning information.
So let's get sensible 20hz seems more workable. Infinite baffle appeals more than an in room sub but means cutting a hole in the ceiling. I have a choice of amps but guess I would need to combine left and right to make a mono sub otherwise if I have left and right drivers facing each other out of phase passages would cancel each other out. Much to consider with this.

[JLM]

I.B. Are powerful, can vibrate ceiling (or floor) construction. Can be ceiling, floor, or wall mounted. But slamming doors (that can blow the cones out), insulation breeches (if installed on the outside envelope in non-mild climates), and noise complaints must be considered.

[JohnR]

Here's another link that may be of interest - http://www.hometheatershack.com/forums/ib-infinite-baffle-subwoofer-build-projects/54452-official-ib-infinite-baffle-faq.html - I've only skimmed it but it seems to put everything in one place.

I agree, I have corrections for my RadioShack meter down to 20 Hz, but can't imagine what musical program material besides record warps are reproduced down at 10 Hz.  Thunder?  I guess there's some special effects stuff to reproduce there.  And in a 10'x10' room, I'd think it pretty hard to get 10 Hz with any volume.

Hi Dan, one reason for wanting a response to 10 Hz is not to reproduce thunder or organ pipes the length of a football field, it's to improve the transient response of the system (IMO ) A "perfect transient" has response to DC; so the lower you go, the closer you will get to that. However there are lots of other things in the way as well, I'm just talking theory and generalities... I don't think flat to 10 Hz is necessary (or desirable) but a good sealed sub system with some EQ and room gain (a small room will help actually) can get you further than you would think. To illustrate here's a graph I took a little while ago with a pair of 12" sealed subs (anechoic f3= 30Hz), red is no EQ, blue is with EQ:



At 10 Hz everything is displacement-limited, hence the question about output.

I can't install an IB but one of the things I think important to note from the link above is that you basically need to have a sub or subs already, in order to figure out the best location for the manifold openings. Or you could of course just wing it

[versus rider]

The point of IB is it won't take up valuable floor space that I have just reclaimed by selling my horn system, huge 15" bass boxes and 200hz front horns filled the end of the room either side of a large rack for three amps, cdp, turntable, cassette deck and DVD. The problem I see is having to buy different drivers with rubber surrounds for IB.

[JohnR]

The rubber surround is for the cold?

[jk@home]

The point of IB is it won't take up valuable floor space that I have just reclaimed by selling my horn system, huge 15" bass boxes and 200hz front horns filled the end of the room either side of a large rack for three amps, cdp, turntable, cassette deck and DVD. The problem I see is having to buy different drivers with rubber surrounds for IB.

Bingo, that was the main reason I went with IB. My system is for music only, and the ceiling has shown very little vibration. Heck I have a ceiling fan in between the two manifolds, and have never noticed any extra vibration from it.

If you go with a single manifold with two drivers, one stereo amp will be fine. You don't wire them out of phase from each other. Most folks use inexpensive high wattage pro amps.

Most IB drivers are based on car drivers. If it can survive in a car, it should be fine for your attic or craw space. I'm using AE IB15 drivers which are now discontinued, but John J. now these available:

http://www.aespeakers.com/drivers.php?driver_id=37

For more driver ideas, look at the "Loudspeakers" section of the COIB.

http://ibsubwoofers.proboards.com/board/16/loudspeakers

[jk@home]

Here's another link that may be of interest - http://www.hometheatershack.com/forums/ib-infinite-baffle-subwoofer-build-projects/54452-official-ib-infinite-baffle-faq.html - I've only skimmed it but it seems to put everything in one place.

Agree, they did a nice job there.