It is hard to get used to the idea of 1 or 3 LF channels supporting a "stereo" hi-fi.  But the way it winds up working is that the "wrong number" of channels, or sources in the "wrong spots" can make things sound worse, because of cancellation and/or augmentation.  So who knows what the "right number" would be in your big, framed house at this point?  Maybe 1 channel would work better than 2; or maybe 3 would work better than 2.  Just as interesting to me will be the new requirements for mid-upper bass, to go with your new ceiling horns, and watching how you will get the whole low end integrated in the large space (without EQ?).

BTW, congratulations and mazel tov for safe and tidy insertion of the big ceiling horns!  I see now it was not so high as I had thought; but still too far to drop something like that!

And did you say, "240' of speaker cable"!?!

Best regards,
Paul S

jessie.dazzle wrote:

For a lot of reasons, I'd vote for an alternate placement. You've got that basement, so why not use it as a rear chamber? You might be able to use the volume "as is", without building a proper rear chamber. In this case, assuming stereo configuration, do you think it would be necessary to separate the basement into two volumes so the drivers do not communicate with each other via the basement?

Yes, there are many reasons why I'd vote for an alternate placement for LF section/s as well. Still the location I describe has some very important benefits at this moment: 1) It will not stress the suspended floor in my listening room 2) I need to do nothing to make it work as I do have the enclosures and amplification.

jessie.dazzle wrote:

With regard to power; In my case, in a room that appears larger than your current space, 100 watts for each driver (2 x M1.1) seems to be more than enough; driver sensitivity is nothing special; 94db. I'd expect the amps could run 4 of these drivers with no problem; it would be easy enough to connect the pair to a single amp and find out. I can do it if you want.

I do not know anything about your LF section. What do you use and where does it crossed?

jessie.dazzle wrote:

I only know of one; if we can believe the specs, the McCauley 6174 has Fs at 20Hz.

oxric wrote:

I appears to me that hoping that the first aesthetically pleasing location for your LF driver will actually work in practice is an extreme form of wishful thinking on your part, but I may be wrong and the laws of probability may well be working in your favour. On the other hand, a driver that will probably meet with contempt by many but nonetheless looks on paper quite promising is the Maelstrom-21, with a Fs of around 16.3Hz, if that can be believed. At a price of under $600 apiece, it gives you the option of creating a Geddes based array or a 2-3 driver set-up for very little expense and frees more time and energy analysing and optimising their placement in your room. You can follow the link below. http://www.diycable.com/main/pdf/M21.pdf A speaker designer that I know in the UK has also pointed me to the Volt Radial RV4504 from a reputable manufacturer which seems to be beautifully designed/built and with plenty of thought given to addressing the heat issues, see below, albeit with a Fs of 33Hz. But the designer might be willing to do something fairly custom for you if you want to push the boat out here.  http://www.voltloudspeakers.co.uk/About_Us/about_us.html

Rakesh, thanks, I never heard those drivers I will look into them. My wishful thinking was not only wishful thinking but also a desire to use an existing solution for modeling or ay least temporary use of what I already have. I kind of sick for now building the things and I want this stage to pass. I need a little break from construction phase. The life is going away and I keep building the things… I am too tired from this. My playback in disabled mode for moths and for some time did not have quality time at my home with Sound. I kind of am missing it…. I kind of knew that it will come when I bought the new house but I think I am at final stage. I am planning to make the playback to work with midbass horn and place my woofers in the place behind the middle poll. I might even use the digital EQ to drive it.

I would like to live with it for a while, to get good sound, to setup my analog, to setup electricity, setup speaker positioning… I will research the subject of killer drivers and strategies with LF channels but I think that my existing LF sections will be good to prototype of what I might get. I never had 42Hz horn and I do not know how the 30Hz LF channel need to work in context of horn. I do feel that will need a direct radiator under the bottom but I at this point I do not know specifics….

jessie.dazzle wrote:

I have 2 ULF "boxes"; each has an 18" McCauley 6174. The enclosures are sealed and each measures 14 cubic feet. They are made from 70mm thick concrete blocks. Power is from a pair of M1.1 amps (100 Watts each).

Presumably that the McCauley drivers are fine I think would be the very ultimate ULF channel. The 100 Watts of M1.1 is a bit tricky as Vladimir very conservatively grade them as 100W. Generally in what I seen Lamms are able to pump more than this. I did not measure where they clip but it felt as they are more powerful than some other amps rated at 100W

jessie.dazzle wrote:

However, I recently bought a house in the US and will at some point be moving (its complicated). The house has a basement which might be exploited as a rear chamber. For this reason I am debating weather or not to move the ULF boxes, as they are extremely heavy. This is what's behind the questions in my previous post.

I am bit skeptical for use basement as a rear chamber in my case. My floor is suspended and I do not want any bone vibration take palace when ULF is working. This is why I am trying to put my ULF in another room that does not share the same suspended floor as my listening room. I have Sunfire cub sub that is horrible sonically but able to pump very high pressure, placing it in deferent locations is it very easy to model what and how will vibrate. This is what I will be experimenting when my midbass project will be over. The only viable use of basemen, at least in my case would be if I make woofer sitting in some kind of sealed pipe that goes from basemen floor to basemen ceiling and exhaust into the listening room, but decoupled from the listening room’s floor. I am contemplating it but cutting two 20 holes in listening room floor would require me to be absolutely confident that it is what I want. At this time I do not have this confidence as I am still do not have a clear visualization of what kind ULF sound I would like to make. I do know very precise what I would NOT to have in lowest octave but it is not enough for me.

jessie.dazzle wrote:

I've never seen the cones go beyond maybe 3/16" total excursion …

That is very good. I do not like the drivers that excurt too much. What kind outer suspension it has, is it rubber? The web site does not say anything about it. Anyhow, the amount of pressure McCauley does is not a key factor. I think the key factor would be the degree to which the driver is able to decimate the LF pitches.

jessie.dazzle wrote:

I once looked into this driver and ended up speaking with someone who was involved with their modification... According to what I was told, converting the Aura driver into a Leviathan involved loading on weight to increase the moving mass... I don't like this approach.

Actually it was not increase the moving mass but using much softer suspension (what I was told). If the subject were only about mass then we can do it today with any of the Auras. At that time North Creek had access to made-to-order inner suspension (spider) that was much softer. This combining with the fact that it was the only one 18” woofer with underhang motor and the fact that it has cloth outer suspension in my view made the driver very exclusive.  I have 4 of my Auras but they I think stock versions. I need to measure them to see what they are. But I still will try my arrays of the 10” scan-speaks first. Anyhow, this ULF chals will be a very interesting thing to experiment during the long NE winter….

The Cat

jessie.dazzle wrote:

Romy wrote: "...I think the key factor would be the degree to which the driver is able to decimate the LF pitches..." Pitch: The property of sound that varies with variation in the frequency of vibration.... I decided to look it up and double check my understanding of the word.

jessie.dazzle wrote:

To Southeast Michigan (a suburb north of Detroit); you know, a crisis is a terrible thing to waste!

Romy the Cat wrote:

Even though quantivly and structurally bass is correct but it is not what I am looking.

The bass presentce is fine. I have enough bass and I was very fast found the right balance between ULF and midbass. The B2 amp has enough gain and power to handle that ULF- I run B2 with 7db attenuation. The quality of this bass is still not what I would like it to be. Comparing very fine differences between upper knew of ULF and lower knee of midbass I do feel that midbass is more articulate and coherent. In fact I am not sure if I like the result of “distributed bass”. The second bass module is located at different distance then the first one and I feel it mads the ULF quality. I might do so measurements and to see the arrival phase but with line-level passive crossover I do not think I will be able to do anything with it. The alternative would be to drive ULF location #2 from line level direct but the ULF location #1 from a digital devise with precise phase dialing. This would imply a different amplification and will be too much all together.

Generally the popular idea that at LF the time arrival becomes non-critical look absolutely ridicules as far as my experiments show. In fact the wrong arrivals of my ULF are the thing that bothers ma a lot in my current setup.

Anyhow, I am planning to close the book on the ULF channels this weekend. The pane is to measure and to calibrate bass with ULF firing from two locations.  If it does not work then get rid of the location #2 and keep the location #1. Then adding a speaker level coil to the bass modules in the location #1 I will be trying to align the bass arrival to the rest of the sound. This might be an interesting solution as I would not mind if bass filter will be a bit sharper but the experiment with SMS crossover show that a full third order is too sharp and the arrival time become too far behind. I might try the trick with a fraction order crossover that was so successful with midbass. The problem that extra coil’s DCR driving the ULF is usually not very good idea. I was able to avoid punishment with it in midbass channel but I do not know if it will work in ULF. I need to hear how it will turn out….