Steps to reproduce:

1. Open NVDA
2. Press NVDA+ctrl+s and select Microsoft speech API 5 as synth driver
3. Use the synth settings ring to enable the voice speed boost, enable it
4. Use the synth settings ring to change the voice
5. Check whether speed boost is still on

Actual behavior:

The voice speed changes to its original value before enabling speed boost, but the speed boost is still on.
You need to turn speed boost off and on to regain the higher voice speed everytiime when changing the voice.
This does not occur with One Core voices.

Expected behavior:

Changing the voice of the synth should respect the voice boost setting.

NVDA logs, crash dumps and other attachments:

n/a

System configuration

NVDA installed/portable/running from source:

Installed

NVDA version:

alpha-35291,e2d464f5 (2025.1.0.35291)

Windows version:

Windows 11 24 H2

Name and version of other software in use when reproducing the issue:

n/a

Other information about your system:

n/a

Other questions

Does the issue still occur after restarting your computer?

yes

Have you tried any other versions of NVDA? If so, please report their behaviors.

n/a

If NVDA add-ons are disabled, is your problem still occurring?

yes

Does the issue still occur after you run the COM Registration Fixing Tool in NVDA's tools menu?

yes