maybe an interesting project. I got 15" drivers which were a special design for a horn loaded contstructions with very strong magnet system, a large Voice Coil and more than 1/2 inch linear excursion each direction.

 

I did the woodcutting while a friend did the calculations and measurements for my project. After 6 prototypes the fineal result.

Useable up to 200Hz, extreme hard kickbass and also very tight and deep. -6db point at 42Hz.

I prefer the crossover at 160-180Hz. 190Hz is a lambda/4 resonance which should be EQed -3db. Otherwise the system doesn`t need any equalizing.

 

X3 is the name because of 3000W amping power used for one cabinet. With 35Hz lowcut the driver is kept within its linear excursion. The sensitivity is measured with 2V, because 2 drivers parallel so with 1W.

 

Max. SPL calculated around 140db. Even 4000W are possible, but my amps are not capable of this and the benefit is the rise the lowcut to 40Hz... so I prefer deep bass ;)

 

 

 

 

 

And nearly forgotten through the hornloading it becomes more flatten in stacks of 4. Stack of 4 has a sensitivity of 107db flat to 45Hz. -6db at 38Hz.

 

Keep smiling,

Andi.

 

Bevor I`ve tested 18Sound 15LW1401. Very good speakers but not as good as the new ones. Now I get 1db more sensitivity, 1db more power handling and below 50Hz 3-4db more max. SPL becuase of excursion. I`d like to say it sounds like a few db, but it`s a difference as day and night.

sorry for loads of questions!

 

I was going to ask the same question.

 

As I remember the original design with that driver on a front loaded horn was flat from 45-200Hz and had an efficiency of 107db with 1x15". But it was a 500 Liter design. This has less than 250 Liter!

 

So for comparison on same volume:

One Horn (500l): 140db max. SPL                    (with 1500W amping)

2 x X3 hybrid (500l): 146db max. SPL               (with 6000W amping)

 

But with given amping of 6000W, you can supply 4 Horns => 150db! but 4 times bigger for transportation. For this I`m talking about max. Output/Truckspace size. And with this efficiency of the hybrid you can do a funeral for a lot of normal frontloaded horns. There are not too many designs delivering more around 100db sensivity at 50Hz in single mode operation. And most of them are limited in low frequency output due to excurision...

 

 

@MarjanM, maybe you should compare more exactly or measure real subs by yourself. On datasheets you easily can find 102db for 2x15" but not in real world.

 

Compared to this size it`s very good. You must include that this are high excursion drivers with a lot of move mass. Beeing capable of 6db more LF output than a conventional driver.

 

When using another driver you need a new enclosure. The LW1401 was close in construction, but not exactly the same. But it was the best driver I could find before! For a few drivers feel free to contact, I bought a lot to get em cheap. For all who planning more of them I can give you an TSP Set you have to achieve.

I can see nothing to be meant 6th order in this construction

The rear of the driver fires into a chamber connected to the outside world by a hornlike port. The front of the driver has air inside the cone possible acting as chamber. Asides, the front of the driver fires into a very short horn/waveguide. This 6th order alignment can be seen in the measurements aswell, introducing a 10 dB drop orso beyond a certain point.

So basically you have a box that have no exact plans, with the unknown driver and some graphs. Great, that will help us a lot.

He mentioned the box is 75 x 75 x 42 cm (my rough guess would be 80 x 80 x 45 cm). The former means an external volume of 236 liter, meaning an internal volume of about 190 liter, spread amongst 2 drivers, so 95 liter each. If the picture is to scale, it means the non-expanding port is about 34 cm long, with an area of ~275 cm^2 per driver, then expanding over another 30 cm towards ~1400 cm^2. Meaning 850 cm^2 right in front of the driver. The last 5-8 cm is non expanding.

 

Hornresp input parameters (for 75 x 75 x 42) would look like the following:

S1; 275, S2;275, L12; 0,01, S3; 275, L23; 34, S4; 850, L34; 15, S5; 1400, L45; 22, Vtc; 50000, Atc; say Sd (not important if resonances are masked). Sim'ed as tapped horn off course and remembering to put the entire graph 5-10 Hz to the left.

Can you explain to me how having a big excursion figures helps in increasing the output for 6db?

Theoretically doubling the excursion will bring you an increase of 6 dB. I.e. power compression set aside.

If you take any 99db driver and put two of them in a big enough box and tune it correctly you can have 102db with ease. And it can go a lot lower than 50Hz

A 15", 99dB/W/m driver will do so at 100-200 Hz. At 50 Hz it will most likely drop to 95 dB/W/m.

 

Can you explain the theory behind your box? How low do the port is tuning the box? Is it bandpass or just a reflex box? To me it is a simple clam shelf double 15 box with a big port.

To me it's a tapped band pass horn. I'd say the HR-sim says it all.

 

Best regards Johan

What model/brand is it?

 

http://img163.imageshack.us/i/tappedbph.jpg/">

 

If this is so far from the truth, could you elaborate your though pattern into arguments?

 

 

Best regards Johan

 

A BP 6th order with good group delay is very useless for PA system because of very low output.

 

Maybe we are talking here about a 6th order system, but not with double helmholtz resonator. And I think because of this the design has its impressive impuls reproduction.

 

It has only one helmholtz (back volume compliance with hornpath and front volume mass) resonator and this one is very good damped.

 

 

 

 

Best regards Johan

500l was for comparison with the horn.

 

You should not guess too much like this: (2 resonate chambers sharing the same port)

So you`re telling when using 2 bass reflex cabs parallel they get 6th order. Will you still agree with your comment? And if you`re talking about the front this is not a volume with compilance. Just some added mass which adds to the horn port which becomes virtually longer.

 

I`ll try to get impedance plots.

 

For details on this project you can send a PM. I`ll try to give the answers required.