I never used that Philips remote, but you slide your Roku remote that does control the Streambar audio into the Philips remote, doesn't the side keys press the keys on the Roku remote in affect controlling the volume of the Streambar?
I know of no universal remote preset with CEC Roku commands the Roku Soundbar and Streambars remotes have mapped to the power and volume keys on their remotes. UEI made universal remotes under such brands as One-for-all, Inteset, Onn, and Insignia will give access to those commands after you map 5-digit codes for each command. UEI remotes give you access to advanced codes or EFC's, these are 5-digit codes for individual functions. UEI remotes have had these since the 1980's. I would return the Philips and get the Insignia 8-1 universal remote from Best buy its on sale at half price for $19.99:
Insignia™ 8-Device Backlit Universal Remote Black NS-RMT8D21 - Best Buy
The Roku setup code is 3061, to map the missing audio commands using these codes: Vol Up- 00134, Vol Down-00136, Mute- 00140, and Tv Power-00147:
1. Roku device key:
2. press and hold SETUP for two blinks
3. enter 9 9 4
4. Tap SETUP for one blink
5. enter 5-digit code from above
6. pick a key
Do the same for other commands, entering a different code in step five, and picking a different key in step six.
Saying all that, if you have the Streambar connected to the ARC input of your TV, and have CEC turned on, and refesh the CEC devices in your tv settings. Then you don't need the Roku Streambar audio commands at all, just your tv code and its volume will control your Streambar volume.
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