Better Tone?

Yes, hours of practice. Many, many hours.

 

This ^^^^^ first and foremost .....

But to more directly answer your queston, assuming you are new to bow work, try to use different types of pressure on the strings. You'll likely find a "sweet spot" that works for you, your bow and your bass.

But, this is really the answer:

 

Technique and equipment are important.

Make sure your bow hair is clean, not sticking together, not too much rosin.

You will also have to find the perfect bow position between the bridge and FB for any given note, the correct pressure, speed and angle of hair.

Should keep you occupied for the next couple of decades

 

What you're describing sounds as if the tip of the bow is lower than your hand. Practice in front of a mirror and draw the bow at a 90 degree angle to the strings.

 

funnily enough that's the most reassuring thing i've heard for a while ...

 

So, you've got several variables to play with:

Bow weight (as in, how much of your arm weight you let fall through the bow... not exactly pressure)
Bow speed
Position lengthways (this should move closer to the bridge as the note moves higher up the string, the sound gets brighter closer to the bridge so you can use this to help match your lower strings to the upper strings in high positions)
Tip angle (which should be roughly 90° but you can let it vary a little)
Roll angle of the bow (are you playing with the hair square on, or on one edge?)

All of these vary with time during a stroke.

Scratchiness is usually due to scraping the start of the note; you need to practice getting a clean start, as if you don't make a scratch then it won't develop over time unless you are waaaay too close to the bridge.

There are two extremes of clean tone:

One, you play near the end of the fingerboard with a fast and relatively light bow. This makes a big, round boomy tone that nevertheless isn't all that loud; and, because it uses a lot of bow, you can't really play super-long tones this way. Good for Viennese orchestra music... classic waltz stroke.

Secondly, you play much closer to the bridge (40mm or so from it, between two and three finger widths away), with a far heavier bow and slow stroke. This gives you much more power, but also a hard clear tone (and it's harder to avoid the scratch). This is the so-called 'Gary Karr' method, which is good for solo work and the 20th century orchestra repertoire. I rather head in this direction as an orchestral default, at least for louder dynamics, but this is also a matter for fitting in with the style of the orchestra's playing.

Of course, you use each (and all the variations in between) as appropriate musically, but it's good to know where the ends of the scale are.

And yes, it does take a while to learn all this... but if you do it systematically, it need not be a decade (couple of years, though...). You will always need to think through what stroke to use when, especially in solo music.