About to start 4 Tuba 24's double BP102 4Ohm!

[Grant Bunter]

35V across a series pair of 4 ohm bp102. 17V each.

Sorry Gregory, that isn't correct.

As per the plans...
With series wired drivers the voltage may be doubled. In the case of the 4 ohm BP102 one driver, or any number in parallel, will handle 25 volts, while a pair in series will take 50 volts.

I suppose that's because a series pair of 4 ohms in this case would lead to a cab impedance of 10 ohms...

[Gregory East]

BP102 done got a big old uprating lately? Even Bassmonster's plans said 35V (for an 8 ohm presumably )

[Grant Bunter]

Yep 35V for an 8ohm BP102 is correct as well.

[Bill Fitzmaurice]

35V across a series pair of 4 ohm bp102. 17V each.

Sorry Gregory, that isn't correct.

As per the plans...
With series wired drivers the voltage may be doubled. In the case of the 4 ohm BP102 one driver, or any number in parallel, will handle 25 volts, while a pair in series will take 50 volts.

I suppose that's because a series pair of 4 ohms in this case would lead to a cab impedance of 10 ohms...

The BP102 4 ohm really isn't. If it was it would have half the Le that the 8 ohm version does, and would take half the voltage that the 8 ohm does. But the 8 ohm Le is .83 mH, the 4 ohm Le is .68 mH, so the impedance of the 4 ohm is more like 3/5 that of the 8 ohm. Otherwise the voltage limit for the 4 ohm would be 17.5 volt.

[Grant Bunter]

Thanks Bill,
Still so much more to learn...

[Gregory East]

Yeah, thanks Bill. I was wondering about the free lunch. As usual, it's not there.

[djlivex]

Ok I just glued the last panel (bottom piece) I am about to put in the lower braces and panel 11 reflector, I was thinking do you think it's a good idea to put in the woofers before putting the left side panel? I will put plastic sheeting around the woofers so that no glue will touch it, instead of cutting another hole on the other side (left side)? Thanks I'll post pictures later today when I am done with the braces and reflector.

[88h88]

The question is could you get your hands around the other side fairly easily in the event of a driver dying for some reason? I'd rather go to the trouble of putting another access hatch on the other side than it be a 50/50 chance I could actually get the driver out and replace it.

[djlivex]

That's another chance for air leaks, when building the back chamber dual loaded I made use there is enough PL all around the flange mounting. Then cutting again, and the T-Nuts I drilled the holes in the 60 degree position not 90 degree from the side panel. So that the allen wrench and my hand have enough room to twist the bolt. I don't know seems alot of work for another access panel?