My apologies for not getting back to you sooner… Moving to the new place has turned out to be a huge task, but worth it, as this new home actually has a place to work, not to mention a much better selection of recorded music at the local library. I have also managed to round up most of the materials for construction of the horns.
While all this has been going on, I have been establishing a sonic reference in the new room by listening a lot to my existing system (which sounds much better on dedicated circuits, isolated ground, and connected directly to 220v. mains… was previously using a large power regenerator set for 110v/60Hz).
Good to see the success with the new Fundamentals Channel has you thinking… If you don’t have a 5-Channel version running by the time I get around to building mine, it would not be that much more work for me to make a second pair in parallel…
By the way, a big M E O W for your work with this new channel (I have some questions on the new horns, but will keep them for the appropriate thread).
In my case, because I will soon have more horns, I am now very much wishing I had started by building a pair of simple amps…
To answer your questions on choice of frequency ranges (sorry if this diverges from the 5-Channel thread)…
First of all, this project is in my case primarily about education. Myself not yet being an "Experienced Horn Guy", what I need more than anything is to establish a reference. Like most people, I have not yet had the occasion to hear a "properly done" horn system. Since there seem to be very few of these around, I have chosen to educate myself the hard way, and just build one myself.
Due to abilities that come with having a very sordid past, it is relatively easy for me to produce horns having a diameter up to 40 inches. In the interest of establishing a starting point, I am taking my best shot, based on what I am at this point able to understand in matching a driver to a horn, and also of course based on your experiences (thank you very much). I am fully aware that I may have to do some of the work more than once. I will of course make every attempt to insure getting the 45hz horns right the first time.
Looking at your notes in "Over 8,500 Words About My Playback", you spent "a few years" just finding a suitable upper bass driver, and god only knows how long you spent considering drivers for all the other frequencies.
There may be better drivers out there, but with my level of experience, I doubt my abilities to recognize them. So though it may resemble laziness on my part (remember, this is the same person that will be constructing a pair of 45Hz straight horns…), it is smarter from my point of view, to establish this starting point, and get on with the physical work, basing it on existing research ; i.e., if you don’t mind, on your research. It is best that I do this now, because later I may have already developed a "Horn Ego" sufficiently large to prevent such a shameless approach ! I sincerely hope you are not bothered by this… Please say so if you are.
My choice of drivers, as well as physical horn characteristics are therefore based either on what you have ended up with, or what I have been able to understand you would have preferred.
In the case of the Upper Bass Channel… Why 115Hz horn ?
Simple ; I was lucky enough to convince Fane to make a pair of the discontinued Studio 8Ms (16 Ohm). Again, this driver, and the characteristics of your Upper Bass horn seem like a good place to start.
I was originally not going to start by building a Fundamentals Channel… It turned out that In buying S2s, I ended up with 2 pairs that seem very well matched (I bought 4 drivers thinking I would make a selection, keeping the two best matched). So, I now have what I need to make this channel as well. I will base the Fundamentals horn on your observations, and will likely be starting off with a larger horn (yes, further obscuring the tweeters !), while trying to stick with first order X-overs.
The 45Hz horns with Vitavox AK151s are what I will be using in place of multi-driver line arrays. 45Hz may not be the final number… I have the space to go a bit lower if necessary.
For frequencies below what will be produced by the 45Hz horns, I am not immediately concerned (I have enough work for now), but am seriously considering a pair of McCauley 6174s, direct radiating, in large sealed enclosures. These drivers have Fs of 20Hz, a 94db sensitivity rating, high excursion, and a paper cone…Manufacturer recommends 6ft³ enclosure volume, so not huge. And… a big plus, I can get them in Europe. As previously stated, the DSET amps will not drive this channel (plan to use a pair of 100 watt hybrid monoblocks).
As always, thanks for your comments,