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Pros / Cons of the IMBE / md380-emu / ThumbDV for DMR to analog audio quality

David Ranch
 


Hello Everyone,

I've successfully setup DV-Switch on a Raspberry Pi to serve as a full time DMR Talkgroup to Analog repeater bridge.  It seems to work well but I have questions about the audio quality. 

The system is currently using the IMBE software emulation but the audio isn't great.  I've been trying to find qualitative comparisons of the IMBE emulator vs the md380 emulator vs a real AMBE chip solution like NW Digital's ThumbDV product out on the Internet but I'm not finding anything.  Is anyone aware of any URLs out there that tries to break this down a bit?  I know audio quality can be subjective so something that has audio clips of original test audio and resulting IMBE, md380-emu, and ThumbDV would be great.

--David
KI6ZHD

Steve N4IRS
 

David,
It's pretty simple really:
DV3000 Best audio for AMBE and D-Star. No P25
MD380-emu Good audio for AMBE. No D-Star or P25
OP25 (built into AB) OK audio for AMBE. Lousy audio for D-Star. Good audio of P25

Hope this helps,
73, Steve N4IRS


On 8/24/19 11:42 AM, David Ranch wrote:

Hello Everyone,

I've successfully setup DV-Switch on a Raspberry Pi to serve as a full time DMR Talkgroup to Analog repeater bridge.  It seems to work well but I have questions about the audio quality. 

The system is currently using the IMBE software emulation but the audio isn't great.  I've been trying to find qualitative comparisons of the IMBE emulator vs the md380 emulator vs a real AMBE chip solution like NW Digital's ThumbDV product out on the Internet but I'm not finding anything.  Is anyone aware of any URLs out there that tries to break this down a bit?  I know audio quality can be subjective so something that has audio clips of original test audio and resulting IMBE, md380-emu, and ThumbDV would be great.

--David
KI6ZHD

David Ranch
 


Hello Steve,

Thanks for the detail.  I assume that there will be no real difference between the NW Digital ThumbDV (USB based) and the DV3000 (Rpi HAT)?  While not important, I assume if P25 isn't supported, that also means YSF-WIDE won't work with these HW solutions either?  What about YSF-Narrow?

--David



On 08/24/2019 08:47 AM, Steve N4IRS wrote:
David,
It's pretty simple really:
DV3000 Best audio for AMBE and D-Star. No P25
MD380-emu Good audio for AMBE. No D-Star or P25
OP25 (built into AB) OK audio for AMBE. Lousy audio for D-Star. Good audio of P25

Hope this helps,
73, Steve N4IRS


On 8/24/19 11:42 AM, David Ranch wrote:

Hello Everyone,

I've successfully setup DV-Switch on a Raspberry Pi to serve as a full time DMR Talkgroup to Analog repeater bridge.  It seems to work well but I have questions about the audio quality. 

The system is currently using the IMBE software emulation but the audio isn't great.  I've been trying to find qualitative comparisons of the IMBE emulator vs the md380 emulator vs a real AMBE chip solution like NW Digital's ThumbDV product out on the Internet but I'm not finding anything.  Is anyone aware of any URLs out there that tries to break this down a bit?  I know audio quality can be subjective so something that has audio clips of original test audio and resulting IMBE, md380-emu, and ThumbDV would be great.

--David
KI6ZHD

Steve N4IRS
 

The DV3000 refers to any of the NWD hardware vocoders. (same chip)
DMR, NXDN and YSFn are all AMBE
P25 and YSFw are IMBE

On 8/24/19 1:21 PM, David Ranch wrote:

Hello Steve,

Thanks for the detail.  I assume that there will be no real difference between the NW Digital ThumbDV (USB based) and the DV3000 (Rpi HAT)?  While not important, I assume if P25 isn't supported, that also means YSF-WIDE won't work with these HW solutions either?  What about YSF-Narrow?

--David



On 08/24/2019 08:47 AM, Steve N4IRS wrote:
David,
It's pretty simple really:
DV3000 Best audio for AMBE and D-Star. No P25
MD380-emu Good audio for AMBE. No D-Star or P25
OP25 (built into AB) OK audio for AMBE. Lousy audio for D-Star. Good audio of P25

Hope this helps,
73, Steve N4IRS
NXD
On 8/24/19 11:42 AM, David Ranch wrote:

Hello Everyone,

I've successfully setup DV-Switch on a Raspberry Pi to serve as a full time DMR Talkgroup to Analog repeater bridge.  It seems to work well but I have questions about the audio quality. 

The system is currently using the IMBE software emulation but the audio isn't great.  I've been trying to find qualitative comparisons of the IMBE emulator vs the md380 emulator vs a real AMBE chip solution like NW Digital's ThumbDV product out on the Internet but I'm not finding anything.  Is anyone aware of any URLs out there that tries to break this down a bit?  I know audio quality can be subjective so something that has audio clips of original test audio and resulting IMBE, md380-emu, and ThumbDV would be great.

--David
KI6ZHD