why is ther such a difference in the motor strenght=bl between the d1 and d2 version of the bl subs

Yes, there would be a BL difference between the two subs... even if they were using the same ID top plate (universal option). But... dont get hung up on Bl as there is quite a bit more to things than that and really only makes any sense at all when referenced to DCR.

You can wire a D2 coil in series and have a much higher Bl than if you wired it in parallel. Does this mean series is better, more efficient, and somehow manages to gain motor strength? Nope. Same old thing... This is how many companies like to rate things... with their coils in series for a higher BL number, then with the coils in parallel for a lower DCR to reference efficiency from at 2.83 V.

Ahhh... marketing

Yes, there would be a BL difference between the two subs... even if they were using the same ID top plate (universal option). But... dont get hung up on Bl as there is quite a bit more to things than that and really only makes any sense at all when referenced to DCR.

You can wire a D2 coil in series and have a much higher Bl than if you wired it in parallel. Does this mean series is better, more efficient, and somehow manages to gain motor strength? Nope. Same old thing... This is how many companies like to rate things... with their coils in series for a higher BL number, then with the coils in parallel for a lower DCR to reference efficiency from at 2.83 V.

Ahhh... marketing

I wanted to ask the same question!

Always thought motor strength = BL(2)/RE...

Then again, I've had quite a bit to drink tonight...so disregard anything I say...

JimJ... yes it is. But not as many people know that formula and use it to compare specs and drivers with. Most people simply look at the Bl number and use that as a guidline... in which case, the larger number for wiring things in series does look better. I do measure all subs in series as you have less margin for error in measuring DCR with the sginficant digits that the VOM has. If you are accurate to .1 Ohms, measuring a D1 coil in parallel yields .4 (in reality about .35) so you are off by about 14%... measuring 1.5 in series is spot on.

I had assumed fosgaholic was talking about the Bl number only... as I have had this question a few different times about why such a performance hit on the Bl in going with the D1 vs D2 (in the case of the Bl its 12.8 vs 19)

Thanks,

Scott

could i possibly get that translated into english.

english? ok .

Don't worry about it, its not that important...match the coils to the amplifier that you are going to use and listen to it

thats what im doing. getting the d1. was hoping to learn somthing about my rather expensive hobbie

could i possibly get that translated into english.

BL product is affected by the resistance of the voice coil.

For example, lets say you had two coils, same everything except one is 4 ohms, the other is 1 ohm. Technically the wire would be a little different, but lets ignore this for now...

If they were put into the same motor, and the BL was 20 for the 4 ohm coil, it would be 10 for the 1 ohm coil.... make sense?

BL^2/RE in this case = 100 N^2/W which is a constant for that driver no matter what the coil config is... there are always small differences here and there, but for the most part you can think of the number as a constant. BL^2/Re tells you which driver has the stronger motor + vc combo so to speak.

BTL > BL > Q > SSD

for example...