StevenA:

Let me begin by saying that I am not an expert in digital signal processing, D/A-converters etc.

The XP-series synthesizers have 16-bit samples, as do all current PCM-synths. It is however important to remember that much of the signal-processing is done at higher resolution. I would not be surprised if the filters, envelope generators, LFOs etc work with higher resolution to reduce errors in the calculations.

We do know that the effects-processor has 20-bit both in and out, and actually delivers a 20-bit audio-signal. The internal processing in the effects-processor is most likely done at 24-bit, again to reduce the errors.

I usually compare this to modifying a picture digitally in Photoshop. You can take a low-resolution image and "map" it in to a higher resolution. Now, the picture itself does not get better from this, but if you start using Photoshop-tools such as smudge in the picture, the higher resolution becomes apparent, and the result is much better than it would be otherwise.

This technique can easily be translated into the audio-world. If you take "low-resolution" sinal, map it into higher resolution, and then process it, the output signal WILL have higher effective resolution.

My conclusion is that the XPs use their 18- or 20-bit converters to their full extent, and that this enhances the quality of the sound. The new XVs all have 24-bit converters. Why would Roland add 4-6 more bits to be unused??!?

As i said, I am not a professional in these fields, but I think this description should be fairly correct..

Stig

[This message has been edited by stigf (edited 03-28-2001).]