Maybe a zobel network is not needed because the baffle width is only 12.5 inches. (Still absorbing as much information as possible, really a noob at this right now)
If this is the case, then we should only need a simple resistor and inductor for the BSC.
Rparallel = Re x (10^db/20 -1)
Rparallel = 5.7 x (10^3/20 -1)
Rparallel = 5.7 x (10^0.15 -1)
Rparallel = 5.7 x 0.413
Rparallel = 5.7 x 0.413
Rparallel = 2.3541
Rparallel = 2.5 Ohms (Parts-Express)
f3 = 4560/Wb
f3 = 4560/12.5"
f3 = 364.8 Hz
Lbsc = Rparallel/(2 * Pi * f3)
Lbsc = 2.3541/(2 * Pi * 364.8)
Lbsc = 2.3541/2292.106
Lbsc = 1.0 mH
Lbsc = 1.0 mH (Parts-Express)
If this is the case, then we should only need a simple resistor and inductor for the BSC.
Rparallel = Re x (10^db/20 -1)
Rparallel = 5.7 x (10^3/20 -1)
Rparallel = 5.7 x (10^0.15 -1)
Rparallel = 5.7 x 0.413
Rparallel = 5.7 x 0.413
Rparallel = 2.3541
Rparallel = 2.5 Ohms (Parts-Express)
f3 = 4560/Wb
f3 = 4560/12.5"
f3 = 364.8 Hz
Lbsc = Rparallel/(2 * Pi * f3)
Lbsc = 2.3541/(2 * Pi * 364.8)
Lbsc = 2.3541/2292.106
Lbsc = 1.0 mH
Lbsc = 1.0 mH (Parts-Express)
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The fewer the components the better. Less cost.
So the BSC you designed, Ron, is a 3db attenuation? That's probably all that's needed with the front port.
So the BSC you designed, Ron, is a 3db attenuation? That's probably all that's needed with the front port.
Correct, 3 dB attenuation. That is just a starting point. I am going to get a few resistors to try since this is my first BSC.
FYI
Rparallel @1dB 0.696
Rparallel @2dB 1.476
Rparallel @3dB 2.351
Rparallel @4dB 3.334
Rparallel @5dB 4.436
Rparallel @6dB 5.673
Lbsc @1dB 0.3
Lbsc @2dB 0.6
Lbsc @3dB 1.0
Lbsc @4dB 1.5
Lbsc @5dB 1.9
Lbsc @6dB 2.5
Rparallel @1dB 0.696
Rparallel @2dB 1.476
Rparallel @3dB 2.351
Rparallel @4dB 3.334
Rparallel @5dB 4.436
Rparallel @6dB 5.673
Lbsc @1dB 0.3
Lbsc @2dB 0.6
Lbsc @3dB 1.0
Lbsc @4dB 1.5
Lbsc @5dB 1.9
Lbsc @6dB 2.5
Or make the BSC easily adjustable so it can be tuned/adjusted for different environments and preferences. Use some sort of jumper or rotary selector to choose different resistor values for different attenuation
Or save your amplifier power and eq it out. Or do the bsc at line level before amp and use much smaller/cheaper inductors and non power resistors. Bsc's burn off power and add phase altering stuff to an otherwise pure full range driver and amp.
My integrated amp does have a 5 band eq, one of which is about 500 hz, which would be convenient for this application. I do like the idea of having the zobel be at line level before the amp, though I listen to mostly vinyl using the amps built in preamp. I don't know how effective feeding a phono signal through a BSC would be.
Interesting, line level would be very nice considering I want to power these with a SET amplifier. You may have just saved me a hundred bucks!
Thanks!
I wonder if the Tang Band W8-1772 would work in this enclosure as well. Maybe Bjorn could run a sim for that. It would be nice to have an enclosure where the driver could be swapped in/out.
Thoughts on this?
Thoughts on this?
Well this enclosure, being quarter wave resonant, would maintain that tune of 35 hz regardless of driver parameters. So if the driver handles "extreme tuning" as I believe Bjorn called it, than it should work. Some drivers require dampening from the enclosure, something that this enclosure design with its large volume and high density stuffing offers little of.
The MLTL generally likes moderate to high Qts parameter drivers, I think the 1772 is a low Qts high Bl driver designed more for BLH's. Easy enough to simulate and see though.
If you were to try the Tang Band W8-1808 it might work. It is very similar to the 1772 but with a higher Qts (along with some other parameters being different). I don't know if the TB drivers are really worth 4 times the price of the Betsy K though. For me, anyway, this is a build where I am trying to get the most out of a limited budget.
Yeah I agree, all in for this build with the Betsy-K I am looking at $215 and change. Really can't beat that, same price as one TB driver.
The W8-1772 works very well in a MLTL cabinet 40" tall and 75L net. The 1808 requires a 48" tall cabinet ant 100L net. I have avoided the 1808 because of the large cabinet it requires. Most users here choose to run the 1808 OB.
Bob
Bob
Yea, I need something with a high sensitivity. I will be using a SET amp so the BetsyK or TB W81772 are my choices right now.
You don't want HD to do most of the cutting. I have yet to find a HD store where the blade on the panel saw wasn't dull. The nice veneer will be a mess. One might be better off spending a bit more and getting the 2x4 purebond sheets shipped to them. More veneer types available as well.