My machine has a rough sound as I sew. The stitches are ok. just rougher sounding than it used to be

Sounds like skipped stitch. First thing: install a brand new needle.

Basic Maintenance Tension Skipped Stitches

Don Ignore Your Sewing Machine Skipping Stitches Simple Solutions


What to Do If Your Sewing Machine Is Skipping Stitches

check thread and make sure thread has been in its threading slot in your bobbin case

1. If you're capable remove the top, bottom and front panels.
2. Take an old rag and clean every part you can. Now, use a qtip to clean other difficult areas.
3. Rotate the hand wheel towards you and check for all moving metal parts that make contact with other metal areas. Oil these areas with sewing machine oil.
4. The front of the machine is where the needle bar and pressure foot bar is. Clean these areas and oil them.
5. Remove all of the parts where the bobbin sits. Clean them. There is the location where they sit on the machine called the race. Clean it and put one drop of oil on it. Put everything back together.
6. Adjust the bobbin.
Look at the figures and information to help you.

Did you replace the needle? Look at the hole in the plate and see if the sides are rough. If they are you may be able to cure them with your finger nail file. There is a hook under the plate that rotates or at least goes half way around. Remove this and check for marks that are rough, especially around the sharp end. If you find them you might be able to save it with some sand paper. Make sure you blow this area out and put a drop of sewing machine oil on the race (where the hook came from). Do all of these. If there is still a problem the needle arm may have gotten bent. Do all of these and you may save it yourself. Do one other thing. If your hook is too rough you can order a new one through the internet for about $ 25. You will only need the brand of sewing machine and model. Hope it works.

An "E8" message appears on the panel.
Description: You tried to select a different stitch while the twin needle sewing setting was selected (the key is lit).


Select an appropriate stitch, or use the single needle sewing.
Note Each time a key pressed or an incorrect operation is performed, a beep is sounded.

• For a correct operationOne beep is sounded.
• If an incorrect operation is performedTwo or four beeps are sounded.
• If the machine locks up, for example, because the thread is tangledThe sewing machine continues to beep for four seconds.
  The machine automatically stops.
  Be sure to check for the cause of the error, and correct it before continuing to sew

it sounds like the machine needs to be serviced.

I would definitely suggest taking the machine to a sewing machine shop to be check

Rewind a bobbin, sounds like it is wound unevenly, remember don't speed when you are winding.

SIX Layers !!!!
You really need a size 16 needle that won't bend and miss the hook by the sound of it....can you sew on less challenging thicknesses OK ??
If not, the timing may need adjusting...here is a link to assist:
HERE

Sounds as though you may have a burr or rough spot on the hook where the bobbin inserts. Run your finger along the edge of the hook to see if there are any rough spots.I'm sure you're going to find at least one from the time you broke the needle.Once you locate it, remove it with an emery stick or small sharpening stone. Polish it so that it is smooth. Should work okay.
sewman7