OK I'll confer, nothing below E. For some ( dumb) reason they decided it's a Fender 4 string P bass. I also use a lot of low D notes and this rules it out. Glad it was a freebie.  

Okay Chevy (hope you own a nice OLD one), first I am astonished that you use notes below E1. I think ample guitar just used the standard bass tuning, i.e. the lowest string is E1. I know that some people tune their guitars in unusal ways, but I had never heard that of basses. Even 6 string basses have usually the lowest string tuned to E1. But beware, I do not want to offend you in any kind, it is just my experience and I do not have a lot of know-how there!
 
One thing that is possible with ample basses (and guitars) is that you can tune them other than to 440Hz (in the Settings panel). So I checked that, but unfortunately the maximum down is only 430Hz. If there had been the possibility to tune down a full half tone (you mentioned it above), then you could have done this in combination with transposing the MIDI one half tone up.
To me it seems the only solution using ample bass for your needs, is to transpose the bass line a half tone up and then consolidate it to audio that is shifted one half tone down with Melodyne. But of course that would be an odd method!
 
Another thing I forgot to say concerning shifting the MIDI 50ms ahead: In Sonar I had always to calculate with the tempo (bpm) how many ticks correspond to 50ms (ticks = 50 * tempo * 960 / 60000 (using 960 ticks per quarter note)). Perhaps you or anybody else knows a better way?

marled
 Even 6 string basses have usually the lowest string tuned to E1. But beware, I do not want to offend you in any kind, it is just my experience and I do not have a lot of know-how there!

5 strings usually add a low B string. 6 string usually add a High C
 

Kamikaze

marled
 Even 6 string basses have usually the lowest string tuned to E1. But beware, I do not want to offend you in any kind, it is just my experience and I do not have a lot of know-how there!

5 strings usually add a low B string. 6 string usually add a High C
 

+1
 
This is true unless its a Fender VI (or Baritone guitar).

OK here's the deal- The P bass Lite only goes to E -  the paid full version goes to low B just like a 5 string. So if you like the VST you need to anti up and buy the full version. 
I have a lot of songs that use low D so I'll have to think about this. I think I'll just watch for a deal. 
 
I play a Godin 5 String Bass and playing live it's pretty rare I'll use below low D.  Without a sub system or a refrigerator sized amp those low notes don't cut through. So I find the low D is as far as I need to go. 
I often am tempted to try a heavy gauge set on my Hondo Bass and drop tune it. 
But 5 string is nice for certain keys like Bb which this one person I accompany sometimes uses a lot. 

chuckebaby

Kamikaze

marled
 Even 6 string basses have usually the lowest string tuned to E1. But beware, I do not want to offend you in any kind, it is just my experience and I do not have a lot of know-how there!

5 strings usually add a low B string. 6 string usually add a High C
 

+1
 
This is true unless its a Fender VI (or Baritone guitar).

Thank you guys! You have taught me something more!
I have read also a bit on the internet and it seems it is also quite common to use other tunings (down to D1) on 4 string basses like Johnny V says. Sorry, it seems I have disgraced myself! But in all the bands I played guitar the bassist was always using only a 4 string bass with standard tuning and so have I later on using the Aria SB II.

I've been trying Ample Bass P Lite II on a song with the low E tuned to D without any problems. Just needed to click and turn the tuning key to tune it down. I have a P and a Jazz bass but am looking to make things easier if I can get some nice sounds.

marled

chuckebaby

Kamikaze

marled
 Even 6 string basses have usually the lowest string tuned to E1. But beware, I do not want to offend you in any kind, it is just my experience and I do not have a lot of know-how there!

5 strings usually add a low B string. 6 string usually add a High C
 

+1
 
This is true unless its a Fender VI (or Baritone guitar).

Thank you guys! You have taught me something more!
I have read also a bit on the internet and it seems it is also quite common to use other tunings (down to D1) on 4 string basses like Johnny V says. Sorry, it seems I have disgraced myself! But in all the bands I played guitar the bassist was always using only a 4 string bass with standard tuning and so have I later on using the Aria pro II.

I totally understand where your coming from man.
I play a 4 string for 90% of the stuff I do but I do own 2 different 5 string basses and a Fender squire VI (which is a Bi%$* to keep in tune if you dare use the tremolo system). But the only reason I know this is because bass is my second instrument next to guitar (well voice being my main instrument). but for the majority of people out there a 4 string will complete any task.
 
Ive found similar issues using Bass sims (trying to tune down).
I find the IK Modo has a similar problem when going below Eb. instead they force you to use a 5 string VST-I.
Not really a big fan of the IK modo.
 

Oh so you actually put the VST out of tune. I'm not sure I like that idea as that changes the sound of the samples. 

I used to do what most of you guys are doing, using my old Ibanez Roadstar II I bought new in 83, and a newish Ibanez 5 string, but mainly doubling up with the midi and audio tracks. But both my bass's are relatively dirty sounds compared to say a J or particularly a P bass, so recently I bought a new PJ active special after many enquiries. I just havn't looked back. Everything I've tracked recently is so clean and full. No more pulling out nasty frequencies. No more editing of the waveform to clean up volume levels. But in particular, no more looking to add to, or change, the sound, because whatever I want, I can pretty much dial up on the bass. The beauty of this model is you can switch off the electronics and operate in passive mode only. The only thing I've done is drop a track an octave using Melodyne, dirty it up a bit, and mix it with the original track for extra growl and subs.
 
But to answer the op's question. I did something similar last week to what you want using Neutron 2's transient shaper. I was blown away by how good and simple it was. Worked brilliantly.
 
cheers
 
Dave.