JBL MS-8 Crossover Settings? - Looking for Recommendations

I have a similar setup in terms of speakers and sizing.. I had a lot of issues using certain crossover points and speaker setups, so I'll tell you what worked..


May be different for you, but I had a huge issue with a 3.5inch center channel with the ms8.. If I tried to cross over at 300hz 24db/octave, it would completely destroy my midbass. It EQ'ed every speaker in the car to sound like a 3.5, despite them being crossed over much lower. Not sure why it tries to level match so much below the crossover point, but I just know I tried probably 50 times before I "solved it"..

I'd suggest crossing the 3.5 over at 500hz, that seemed to fix my midbass issues, 500hz 24db slope and the midbass isnt' massively cut by the auto EQ.

For the rest of your xover points, I'd do other mids around 100hz. If your using the passives that came with the speakers, there is a "different" setting you can try, that worked best for me.

Tell the system during setup there is NO sub in the car. Then choose 2 way for your fronts. The sub will be the bottom half of your 2 way. So pick a hpf appropriate for your subwoofer, probably 20-25hz. Then it'll ask for your lpf, which will be 100hz.

The advantage to his is 2 fold. One it will time align the sub, second, it will sometimes give a more accurate calibration.

I know whenever I choose subwoofer, no matter how gains are set my bass is boomy. Having it setup where it EQ's the sub like a front speaker, it does a GREAT job.

Anyways, feel free to start by trying more standard numbers.. 300hz for you 3.5, 80-100hz for the fronts, and tell the ms8 you have a sub.. If it works fine for you that way, go with it..

Oh lastly, i would level match the rest of your speakers to your center before it calibrates. Seems the closer you start to a "good" tune, the better the ms8 can do. -35 will likely be a good volume to level match everything when doing sweeps.

T3mpest said:

Oh lastly, i would level match the rest of your speakers to your center before it calibrates. Seems the closer you start to a "good" tune, the better the ms8 can do. -35 will likely be a good volume to level match everything when doing sweeps.

Click to expand...

Thanks T3mpest for your detailed response, that is a lot of good information... and to billw.

What would the best way to level match my amplifiers with the MS-8 be? Would this be lowering the gains on the speaker amplifiers to get in the dB range of the center channel? Should I measure the output of the MS-8 Center High Level with a DMM? Just curious how this would be done.

As far as setting the gains properly on my two Kicker amplifiers, correct me if I made any mistakes here:

So for the Kicker SX700.4 its total output (RMS) is: 82 Watts x 4 Channels @ 4-Ohms. However this amplifier has basically two separate amps inside of it. So it is really two 82 Watts x 2 Channels @ 4-Ohms as there are two separate gain controls.

So if math serves me right: 82 Watts RMS x4 Channels=328 x 4-Ohms = 1312 ... Divide 1312 in half to account for the two separate internal amps = 656. Then take the square root of 656 which = 25.612 Volts AC..... So I should be looking for this 25.612 Volts AC using a DMM with no speakers connected with a 100Hz Uncompressed Sine wave playing on repeat on the cars CD Player while playing at 75% of max volume?

Similar for my Kicker SX650.1 Class D Sub Amp:
RMS: 650x1 @ 2-Ohms... 650x2=1300.... Square root of 1300 = 36.055 Volts AC. Do this with a 60Hz Uncompressed Sine Wave measured with the DMM?

Did I make any mistakes?

The JBL MS-8 is 18 Watts RMS x 8 Channels @ 4-Ohms.... 18x8=144... 144x4=576.... SQ Root of 576 = 24 Volts AC

Should I try to get my Kicker SX700.4 Speaker amp to the same 24 Volts AC that the JBL MS-8 should be putting out? Or should I keep the kicker amp at its calculated 25.6 Volts AC? I know the numbers are pretty darn close.

Thanks again for anyone who wants to chime in on this...