Low Receive Volume

[njmsa]

We have many clients complaining that calls are too soft when they move from other platforms to 3CX. We are running the latest V16 version of 3CX on VM's in the cloud with Raspberry Pi4 SBC's onsite and Yealink handsets. We're having this issue across many clients. We have found a setting to increase the send volume on the Yealink handsets which works for the sending volume but so far not finding any solutions for the receive volume (the handset is already on maximum volume). Please help?

 

[njmsa]

• 3CX Version, Pro 16.0.9
• Server OS, Debian on VM and on Raspberry Pi (SBC)
• Is the 3CX Server Hosted and where? Hosted
• IP Phone Make/Model/Firmware: Yealink T27
• Provisioning Method: SBC
• Trunk Provider or Gateway Make/Model: Local VOIP Provider
• Has the Firewall Checker passed: Yes
• Are custom Phone Templates being used: No

 

[Alphabetic]

Who is the SIP Provider?

Is this every call?

What codec are you using?

Could you try g711?

 

[njmsa]

The SIP provider is a local provider here in South Africa. We have tried a different SIP provider as well and have not found any noticeable difference.

It's every call yes.

We are using the G729 codec. Unfortunately in South Africa we cannot use G711 or even PCMA/PCMU as all the VOIP providers here mainly use the G729 codec exclusively.

 

[Alphabetic]

And what happens when you simply turn the volume up using the vol key on the phone when using the handset?

 

[njmsa]

Yes we do that but even at the max volume for the handset, it's just still too soft. On the 3CX Apps on mobile it similarly soft (even at max volume). I was hoping there would be a way one could boost the volume on the 3CX PBX but there seems to be no such option.

 

[Alphabetic]

Ok sounds like SIP provider issue, you may need to reach out to them.

https://www.3cx.com/partners/voip-providers/

alternatively I would try one of the above supported providers.

 

[JohnS_3CX]

Yes we do that but even at the max volume for the handset, it's just still too soft. On the 3CX Apps on mobile it similarly soft (even at max volume). I was hoping there would be a way one could boost the volume on the 3CX PBX but there seems to be no such option.

That option does not exist unfortunately, but you haven't mentioned yet whether internal calls (extension to extension) also suffer from this.

The reason I ask is because in those cases, the phones normally send each other audio directly (bypassing the PBX entirely) so that would indicate that no matter what PBX you use, the volume is dependent on the phones.

On the other hand, if it's just external calls that suffer from this then you might have to speak to your provider and see if they offer any tweaks or volume boost from their end.

 

[njmsa]

Thanks, I will do more internal extension to extension testing to compare volume levels and also do some more testing with more VOIP providers.

So in conclusion in your experience, there is definitely no issue with low receive volume?

 

[JohnS_3CX]

So in conclusion in your experience, there is definitely no issue with low receive volume?

Yes, I have a T27 here which I tested and I can definitely say it does not have any volume issues at all.

I dialled *777 and spoke into the handset, and I can hear my voice echoed clearly at middle volume.

 

[njmsa]

What we are finding and I'll be testing this more thoroughly is that when a client moves from for instance a Yeastar PBX to a 3CX PBX then we definitely perceive a drop in maximum receive volume while everything else is equal (connection, network, handset, voip provider)

 

[JohnS_3CX]

Like I mentioned earlier, packets are normally untouched by 3CX so I cannot comment on any other systems.

G.729 is not the best in terms of quality, but in your specific case it appears you do not have any other options, so I can provide you with the following advice to ensure the packets remain untouched across most (if not all) conditions:


1. You said your provider uses G.729, so make sure that is at the top of the list in your trunk (you probably already did this step)

2. Edit each extension manually, and on the Provisioning tab set G.729 on the top priority, for both of the drop down options:

a) 3CX App
b) the deskphone

3. Go to the PBX Settings, click General, and you will see two codec priority lists. Set G.729 at the top for both

4. Reprovision all the deskphones and apps to receive the new codec order, verify that the change took place by looking at the app settings (windows or mobile) and in the deskphone UI.

Now you have the highest chances that the codec remains untouched. Transcoding can degrade the signal, but with the above settings transcoding should nearly never occur.

This means you get to keep the original quality and volume exactly the same as the original.

Hope this helps!