volume control w/ remote (which POT?)

I'm planning to build arduino based Volume controller. I have TiVo hooked up to 30" monitor via HDMI. Out from monitor comes out audio cable and into powered speaker. I want to able to control volume via TiVo IR remote. I have lots of experience with IR receiver hooked to arduino, but never worked with digital POTs.
Could someone recommend me a good IC for this and should I get 10K or 100K pot?

I'd go with 10K. A 10K load is "about right" for a line-level signal. 100K would also probably work.

It would be nice to know what impedances we are working with, but we can guess... The monitor should work with loads of 10K or more (maybe even down to 1k or less), and the active/powered speaker should be 10K or more (maybe as much as 100K). (You may actually have the spec for the speakers.)

If the pot value is too low, you'll "load" the source (TV monitor output), which could lower the signal level and cause distortion. If the value is too high, it will interact with the load (speakers), causing non-linear operation (i.e. 50% on the pot won't be 50% signal level). Also, a change in impedance (such as adding another speaker) will affect the signal more with a higher value pot.

Note that regular audio pots are not linear (they are approximately logarithmic), so any non-linearity caused by the pot-value being too high shouldn't be a problem. You normally want a smaller change for the quiet-half of the pot, and a larger change for the higher-half. (I believe you normally get about 10% signal at the mid-point.) The digital pot is going to be linear, so you need to compensate for that in your software. In the case of a remote (up/down control), you probably want to do that with timing, so that the pot-setting changes more slowly at low volumes, and faster at high volumes.

I can't recommend a specific part. There at least 3 types of digital control... There is parallel, serial, and up/down. You'll have to decide what's best (or easiest) for you. The up/down type seems a bit more fool-proof, since it takes more than one digital glitch to suddenly-accidentally jump-up to full-volume.

If you add a buffer amplifier (op-amp) after the pot then you can use any value 10K or more, and it will be immune to load variations. (But, I'd probably keep it simple if it was me.)

Thank you so much! I'm getting SPI based pot. I guess I'll have to manage logarithmic fade in the code...

I'll choose PT2258