You're right Brett
The first generation of 18LW1400 had an Fs of 25Hz, they are now 31Hz as you pointed out.
I have some 15LW1401 lying around that model very well in a Tapped Horn. The model shows performance similar to the Danley TH115, but it goes a bit lower, and in a slightly larger box. This is a project for a rainy day.
Just for fun have a look at this driver in a 2.8M horn 400-3000cm^2. 40-240Hz BW I like it how there are no large out of band peaks. This should be an easy box to use.
Cheers
William Cowan
The first generation of 18LW1400 had an Fs of 25Hz, they are now 31Hz as you pointed out.
I have some 15LW1401 lying around that model very well in a Tapped Horn. The model shows performance similar to the Danley TH115, but it goes a bit lower, and in a slightly larger box. This is a project for a rainy day.
Just for fun have a look at this driver in a 2.8M horn 400-3000cm^2. 40-240Hz BW I like it how there are no large out of band peaks. This should be an easy box to use.
Cheers
William Cowan
I can't find any information on the Peerless 830564. Has this model been superseded or obsolete?
Also, any thoughts on any Eminence drivers?
Kappalite 3015LF
0.39 Qts
42Hz Fs
9.5mm Xmax
Kilomax Pro 15A
0.39 Qts
41Hz Fs
8mm Xmax
Kilomax Pro 18A
0.56 Qts
33Hz Fs
10mm Xmax
4015LF
0.50 Qts
42Hz Fs
9mm Xmax
4018LF
0.35 Qts (a bit low)
32Hz Fs
8mm Xmax
Also, any thoughts on any Eminence drivers?
Kappalite 3015LF
0.39 Qts
42Hz Fs
9.5mm Xmax
Kilomax Pro 15A
0.39 Qts
41Hz Fs
8mm Xmax
Kilomax Pro 18A
0.56 Qts
33Hz Fs
10mm Xmax
4015LF
0.50 Qts
42Hz Fs
9mm Xmax
4018LF
0.35 Qts (a bit low)
32Hz Fs
8mm Xmax
G'day Martin
The Peerless 830564 is an XLS 12" driver designed for Automotive subwoofer applications. It has dual 4R voicecoils Fs=48.8 Qms=8.06, Qes=0.66 Vas=20.4, Re=1.2 with coils in Parallel, Bl=9.3 Sd=466 Le=0.9mH
It doesn't seem much good for any domestic application, except for in a Tapped Horn, where it appears almost Ideal.
I'm not sure why but it doesn't seem very widely available.
Solen sell the 830877 (Fs=35Hz) which would probably be worth doing a model for. You might be able to ask them if they can get the 830564 in for you.
Cheers
William Cowan
The Peerless 830564 is an XLS 12" driver designed for Automotive subwoofer applications. It has dual 4R voicecoils Fs=48.8 Qms=8.06, Qes=0.66 Vas=20.4, Re=1.2 with coils in Parallel, Bl=9.3 Sd=466 Le=0.9mH
It doesn't seem much good for any domestic application, except for in a Tapped Horn, where it appears almost Ideal.
I'm not sure why but it doesn't seem very widely available.
Solen sell the 830877 (Fs=35Hz) which would probably be worth doing a model for. You might be able to ask them if they can get the 830564 in for you.
Cheers
William Cowan
G'day again
The 830877 actually appears to work very well in a 4-5M long tapped horn. Have a look at 5M long 150-1500cm^2. 300 liters internal volume 25Hz at 130dB when firing from a corner.
Almost double the size of my little 30Hz horn, but it goes nearly 10Hz lower.
I've got too many boxes I want to try!
Cheers
William Cowan
The 830877 actually appears to work very well in a 4-5M long tapped horn. Have a look at 5M long 150-1500cm^2. 300 liters internal volume 25Hz at 130dB when firing from a corner.
Almost double the size of my little 30Hz horn, but it goes nearly 10Hz lower.
I've got too many boxes I want to try!
Cheers
William Cowan
Now that I've had a chance to play with hornresp, I'll answer some of my own questions 
Doesn't look good. I suspect BL is too low. Even in a 4+m horn, not much below 40Hz.
I started nooding with the TB driver and got something promising, and then found sabbelbacke's post back on page 27. My model looks very similar to his but scaled way up to a ~25Hz horn. It has a very small x-section and mouth and I *think* I can fold it down into ~150 L or so. ~95dB/W, and hits xmax at ~30Hz with 25V.
So, the next question is how to deal with the large spikes out of the passband? Notch filters? Brickwall FIR filters? (I guess I'm assuming they are real rather than modelling artifacts)
dwk123 said:
Doesn't look good. I suspect BL is too low. Even in a 4+m horn, not much below 40Hz.
I started nooding with the TB driver and got something promising, and then found sabbelbacke's post back on page 27. My model looks very similar to his but scaled way up to a ~25Hz horn. It has a very small x-section and mouth and I *think* I can fold it down into ~150 L or so. ~95dB/W, and hits xmax at ~30Hz with 25V.
So, the next question is how to deal with the large spikes out of the passband? Notch filters? Brickwall FIR filters? (I guess I'm assuming they are real rather than modelling artifacts)
Attachments
Volvotreter said:
Yes, I'm concerned that the specific size I've modeled is too small. However, the Fitzmaurice Tubas that use this driver also have very small throats, so there is evidence the driver can handle it. Certainly, given it's appallling efficiency, it's required to get any decent output from this driver.
I'll have to pull up my Tuba plans and see how tight a throat Bill uses.
judtoff said:
I couldn't really get a 35Hz version to work with the TB, but if you start with sabbelbacke's version from a couple pages back you should be ok.
My ~25 hz versions look to be foldable into a package 6'x18"x9" or so, which IMHO is pretty small for the performance. I haven't really had a chance to sit down and draw things accurately though, so I'm not 100% sure it's going to work.
www.billfitzmaurice.com
look at the autotuba and table tuba
G'day judtoff
That is an elegant folding scheme. In practice there is actually little need to angle the internal baffles, just step the areas to approximate the desired expansion.
5:1 is too much for any driver I've seen or know of. Even the beefy Lab12 driver would fall apart above 3:1.
Bills horns are well executed compromised front loaded bass horns, but for the volume and mouth size, a well designed Tapped Horn will always work better (flatter, lower, louder). A Tapped horn is uncanny in it's ability to work really well with a very small mouth and total volume.
Cheers
William Cowan
That is an elegant folding scheme. In practice there is actually little need to angle the internal baffles, just step the areas to approximate the desired expansion.
5:1 is too much for any driver I've seen or know of. Even the beefy Lab12 driver would fall apart above 3:1.
Bills horns are well executed compromised front loaded bass horns, but for the volume and mouth size, a well designed Tapped Horn will always work better (flatter, lower, louder). A Tapped horn is uncanny in it's ability to work really well with a very small mouth and total volume.
Cheers
William Cowan
Checking my plans for the Table Tuba, it looks like it runs right around 3:1. I'll play around with my model and see how I can rebalance things.
judtoff - William is spot on. For a given size, a tapped horn will outperform a Tuba if we're only worried about use as a sub. The 'problem' with Bills Tubas is that they're wider band devices, and the sub frequencies are at the lower-efficiency end of their passband. For example, the Table Tuba holds ~95dB efficiency down to 30 Hz, but needs 9 cu ft. My models show a tapped horn holding 95dB down to 25Hz in about half that size.
BTW - your folding scheme is similar to what I'm looking at, although I have one more fold and some changes since I need the mouth halfway down the cabinet. Your diagram should work fine as long as the dimensions are right.
judtoff - William is spot on. For a given size, a tapped horn will outperform a Tuba if we're only worried about use as a sub. The 'problem' with Bills Tubas is that they're wider band devices, and the sub frequencies are at the lower-efficiency end of their passband. For example, the Table Tuba holds ~95dB efficiency down to 30 Hz, but needs 9 cu ft. My models show a tapped horn holding 95dB down to 25Hz in about half that size.
BTW - your folding scheme is similar to what I'm looking at, although I have one more fold and some changes since I need the mouth halfway down the cabinet. Your diagram should work fine as long as the dimensions are right.