Weird..Where's the bass ??

[SEAWOLF97]

My preamp runs 2 amps...the mains are all thats on the big amp, second amp has the MK powered sub and whatever the speaker of the day is.

Last week I put the L88 Novas on the 2nd amp. THE WHOLE SYSTEM HAS BEEN BASS SHY EVER SINCE.

The mains have had little bass , even turning up the sub didnt help.

Today I put the Yammy NS-690/2's back in place of the JBL's and all the bass returned to the system , including mains.

I pay very close attention to polarity.

What happened ?

[Fred Sanford]

My preamp runs 2 amps...the mains are all thats on the big amp, second amp has the MK powered sub and whatever the speaker of the day is.

Last week I put the L88 Novas on the 2nd amp. THE WHOLE SYSTEM HAS BEEN BASS SHY EVER SINCE.

The mains have had little bass , even turning up the sub didnt help.

Today I put the Yammy NS-690/2's back in place of the JBL's and all the bass returned to the system , including mains.

I pay very close attention to polarity.

What happened ?

Polarity would have been my first thought- are the JBLs naturally in phase with the M&K? Does the sub have a phase switch, or have you tried reversing the JBLs?

je

[SEAWOLF97]

Polarity would have been my first thought- are the JBLs naturally in phase with the M&K? Does the sub have a phase switch, or have you tried reversing the JBLs?

je

sub does have a phase switch and I have tried that, but it didnt help. thing is that it throws off the bass on the mains too.

[Fred Sanford]

sub does have a phase switch and I have tried that, but it didnt help. thing is that it throws off the bass on the mains too.

OK, what are your mains, then? The Ohms? Have you tried normal and reverse phase on the JBLs when running alongside your mains (no sub)? Do the JBLs have decent bass on their own, with no sub & no second set of speakers?

You describe the M&K as being on the 2nd amp, do you mean you're running speaker level into the M&K, and then a crossed-over speaker level out of the M&K to the second speakers?

What's the motivation for the second set of speakers, anyway? That situation sort of sets you up for this problem, at all different frequencies.

je

[SEAWOLF97]

OK, what are your mains, then? The Ohms? Have you tried normal and reverse phase on the JBLs when running alongside your mains (no sub)? Do the JBLs have decent bass on their own, with no sub & no second set of speakers?

You describe the M&K as being on the 2nd amp, do you mean you're running speaker level into the M&K, and then a crossed-over speaker level out of the M&K to the second speakers?

What's the motivation for the second set of speakers, anyway? That situation sort of sets you up for this problem, at all different frequencies.

je

there is a multi 6 pair switchbox on the 2nd amp - 1 lead set to MK (terminates there) and 1 to JBL or Yammys..yes the JBLs are OK when running solo. 2nd pair is just for rear fill, I run pretty low in the early AM and have to turn the Ohm's up louder than I'd like in order to fill the room.

But with no other changes , except swapping the Yams for JBLs , all the system bass returns, including the mains.

[sourceoneaudio]

Seawolf,
Have you double checked phasing with a AA battery, also have you tried a sound quality test with out the switch box in play?