Technic

Rear speakers should be connected in series as they are 2ohms each. Although there is not that much power going to the rear speakers it is better to play safe with the amps impedance load.

Try:

- 60Hz/12dB low pass sub
- 175Hz/12db for woofers/components split (Front 2-way)
- rear and center settings are ok, although it could be possible that a 100Hz center will make the voices sound muffled. You could try 150Hz/24db for the center.

Do the calibration at -45db with the amp gains nominal, i.e., the 2V point in your amps gains. Once calibration is done, set MS-8 volume to -6dB and the gains back to minimum. Most probably your OEM woofer midbass level will be low compared with your sub however that's the only amp gain that you should increase until you can balance the its level with the rest of the music. Everything else should be clear and tight (components and sub), they should not sound floppy.

I had the same issue with my underseat midbass, and the only way that I can get it tight is by a slight increase of the gain on those channels. Used to be worst but I got my MS-8 replaced and somehow the new one is much better in getting the midbass levels correct after calibration.

tuffluck

sorry to thread hi-jack, but what does the ms-8 do exactly and how do you hook it up? i have read multiple threads but just don't understand fully what it does to a stock system.

stupiddude

e-manansala, thanks!! Gary should be in touch with me soon.

Tuffluck, MS-8 is basically:

• a device that sums high-level multi-outputs of a head unit, and outputs processed, stereo or multi-channel low level audio.
• a car frequency response auto-fixer, that performs initial calibration using the supplied headphone-like mics, and applies a compensating EQ curve towards the response.
• audio processor (by applying time-delay management) so that the passengers in up to 4 seating positions can perceive the same good audio response and correct timing, as well as Logic 7 surround processing.
• 20w @ 4ohm or 30w @ 2ohm x 8 channel simple amp.

Technic, interesting crossover settings you suggested. I'll try tonight. Also, although I have read a little about measuring amp gains, I do not know the exact steps on measuring it on mine.

• Are you talking about measuring the output of my Logic 7 amp as 2V? Any media I should play during measurement? I read somewhere that I need to use CD with sine wave recorded @ 0dB reference, etc, etc.
• Which ones are 2 ohms, the ones in rear deck (because they are mids and tweeters in parallel), or the ones on rear doors, or all of them?
• While we're at this, do you or anybody know the impedance of those BSW speakers (both mid and tweeter), and the OEM mid-bass subs? I can't find any info on these.

Technic

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All your BSW speakers are 2 ohms, as they are direct OEM replacements. The Logic7 OEM woofers are 4 ohms.

stupiddude

Technic, I owe you one. Followed your suggestions exactly on the -45dB and 2V gain for calibration, and the bass response returned to normal! I also applied the crossover points you suggested, and it seems to sound better than before.

However! I still hear a slight hint of "torn speaker cone" sound when a particular very narrow range of bass freq (kick drum, bass instruments) is triggered, even at normal volume. I know something somewhere is being overdriven when this happens.

I also hear clipping-like sound (the lower frequency of bass instrument does not increase, only the higher freq thumps get louder) when the HU volume exceeds a certain point, even though the sound is not that loud to my ears. I'm pretty certain I did not reach anywhere close to my sub and its amp's max levels when it happened. The "dhhh" sound of kick drum becomes "thhh".

I'm still trying to confirm whether the above is an isolated problem on the high-level input only, or also on the AUX input. I'm also changing the amps from the huge JBL GTOs to much smaller JL Audio XD series (Class D amps) so that the whole thing can fit on a single MDF board covering the back of rear seat.