Use only one coil?!?! Why?

[bes51659]

I am considering to buy a DLS Iridium 10 inch for a 22l sealed enclosure.

For some reason they recommend that I only use one of the 4 ohm coils for that setup. Why not use both? I can see that Q values change for 2 coils. Howcome?

[LBaudio]

lower Fs....read their sound cook book - I think it is mentioned here - http://www.dls.se/econtent/files/449...ook_eng_08.pdf

look also here
http://www.dls.se/econtent/89

[bes51659]

Thanks for the links. I have googled around on other places too. I think I am confused at a higher level now...

One thing I could not understand was how qms (q mechanical) could be affected by how the coils were connected. Qms on DLS iridium 10i with one coil is 2.84, and with both coils 3.44. Why is Qms different?

BL (flux * wire length in cap) on the DLS iridium 10i is higher with one coil than with both. 15.1 instead of 14.6 with coils in parallell. Why is BL not the same, given that the coils are in parallell. More or less like the area of the wires suddently dubbled.

Now, what I think I've learned is that Qts (total) changes because Qes (electrical) changes. Qes is given by Re/BL².Single coil 0.01403 and dual coil 0.00844. Now, I guess that I have lost a constant somewhere, that matches DLS numbers of 0.87 as single and 0.54 in dual config. But why is Re not 1.6 ohm in parallell when the coils are 3.2 ohms?

But the fact that Qts goes down makes the speaker more suitable for the ported box that has a higher Q by itself. Single coil, higher Q, fits better in a sealed box. Am I correct?

I think I will email DLS the q's in black :-)