Newbie Amp Impedence Question - SI BM MKIV / XDI 1100.1

[Jdunk54nl]

I am guessing with the dsp.3 putting out 6v leaving the gain all the way down might not be enough if you are really concerned.
I would just leave the gain all the way down on the amp and turn the output down on the dsp.3. Set it for the proper voltage for whatever power you want (30 volts for the recommenced 450w for the MKiv). Problem solved.

Be careful with the BM's. You will not be able to hear them starting to struggle until its too late and they bottom out and potentially ruin it.

Also from the old stereo integrity site

https://web.archive.org/web/20160308.../#tab-features

Does the BMmkIV need 450 watts to perform?
Absolutely not! The new BMmkIV is a very efficient subwoofer thanks in part to its XBL^2 enabled motor and it does not need every bit of its power handling limit in order to perform well. In its recommended enclosure volume of 0.5^3 sealed, the BMmkIV’s ideal power range is 200 to 350 watts.

[Queef]

Jdunk54nl ,

That should make it w3rk ! Nice !

8 ohm will work if you read through Jdunk54nl's post attachment . Box size determines power handling ?

T/S parameters show measured Re - 6 ohm , wired in series , so slightly more power output than @ 8 ohms from amp !

[moo]

Thanks for the advice everyone!

I did a little more research and found how to calculate the ideal VAC out of the amp. The ideal power range listed on the SI website (cached) for the MKIV is 200-350 W for a .5 ft^3 enclosure.

So if I want to be really careful I can look for sqrt(350 x 2) = ~26 VAC out of the 1100.1 before I connect the sub.


Also I found a great post by Andy on the Audiofrog Facebook page about setting gains in an active system. Had to reread it 20 times to make sure I understood everything, but it made me much more confident to push it to the limit.... (limiiiiiiittttt!)



Sources:
Sonic Electronix Youtube
Audiofrog FB - Setting Gains with a DSP


Edit: aaaannndd I just noticed my posts per page count is way too low. Didn't even see the last two posts.

Also I realized I put DSP.3 instead of DSP.2 that I have. Phew. These silly mistakes are why I worry about blowing shit up haha...

[moo]

T/S parameters show measured Re - 6 ohm , wired in series , so slightly more power output than @ 8 ohms from amp !

Is this to say the impedance of the MKIV when wiring the DVC in series is 6 ohms? Not 8?

I don't quite understand all the math behind T/S params. So apologies if I'm dead wrong lol.

EDIT Measured resistance. Got it.

Follow up. Does it make more sense to use the 6 ohm Re or assume 8 ohm impedance in the formula above?

[mauian]

Thanks for the advice everyone!

I did a little more research and found how to calculate the ideal VAC out of the amp. The ideal power range listed on the SI website (cached) for the MKIV is 200-350 W for a .5 ft^3 enclosure.

So if I want to be really careful I can look for sqrt(350 x 2) = ~26 VAC out of the 1100.1 before I connect the sub.


Also I found a great post by Andy on the Audiofrog Facebook page about setting gains in an active system. Had to reread it 20 times to make sure I understood everything, but it made me much more confident to push it to the limit.... (limiiiiiiittttt!)



Sources:
Sonic Electronix Youtube
Audiofrog FB - Setting Gains with a DSP


Edit: aaaannndd I just noticed my posts per page count is way too low. Didn't even see the last two posts.

Also I realized I put DSP.3 instead of DSP.2 that I have. Phew. These silly mistakes are why I worry about blowing shit up haha...

Yup. I did this calculation for the ideal VAC for my JL 10TW3 which takes 400 watts but my amp puts out 760. I set it up like you did with the formula for 760 and it’s working/sounding great.


Sent from my iPhone using Tapatalk

[Queef]

Be careful with the BM's. You will not be able to hear them starting to struggle until its too late and they bottom out and potentially ruin it.

Start out "safe" , learn sub , then work towards optimization !

[Holmz]

Start out "safe" , learn sub , then work towards optimization !

I am assuming that is not whee the term "sub optimal" comes from?