Low E string 7th fret on notes sound muddy.

[RBX4]

Why?? Help, it's a squire 77 jazz--

[Rockin Mike]

Lots of possible causes. Any of these apply?

Using 2 or more mismatched speaker cabinets.
Does the problem go away on a different rig, or with headphones?

Habit of resting your thumb on the E so it accumulates more gunk.
Does the problem go away for a while with new strings?

Some necks have dead spots especially if the truss has been adjusted a lot.
Is it really a tone difference or a low-volume note you're hearing?

Are you fretting the string right up next to the 7th fret or somewhere behind it?
Right up next to the fret can sound brighter.

Inexpensive basses can be hit-or-miss with quality control.
Does the problem go away when you play a different Squier 77 Jazz?

If you're comparing the sound of E-string-7th fret B with A-string-2nd fret B, the difference in string length and diameter will lend the former a duller, muddier tone by comparison.
Do you hear a similar effect comparing A-string-7th fret E with D-string-2nd fret E?

[RBX4]

I tried almost all if the above, and it sounds like a cheap bass problem n dead spots, we'll see when I take it in to a repairman