Poor Sound Quality

[Mike-2408]

When I am on call I can hear the GSM call receiver very clear, however I am always getting complaints from the GSM call receivers that my voice is bad

I used the android App and WebClient to do the test calls, quality of the sound is bad, I sound like my voice is blocked and my wordings are not clear to the other person.

 

[SteveITS]

See https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/ please.

Is this on internal calls also? *777? How do you have the codecs set up for your apps and SIP trunk?

 

[Mike-2408]

• 3CX Version: 18.0 Update 3 (Build 461)
• Server OS: Debian
• Is the 3CX Server Hosted and where: On-premises
• Has the Firewall Checker passed: YES but only one dint pass (detecting SIP ALG... failed)

Internal/extension calls are perfectly fine, codecs and SIP trunk? I have attached

I am not sure what I have done wrong

 

[HRMNY]

What network firewall are you using? Most have an option to turn off SIP ALG in the settings.

 

[ChrisC_3CX]

That fact that the SIP ALG says failed doesn't mean you've got SIP ALG enabled nor is it necessarily a bad thing either. It means the test did not complete so we really don't know. Since this shouldn't affect audio quality though, I don't think you should dwell on this for now.

If this only happens for external calls, I'd also recommend checking the codecs set on the SIP Trunk in "SIP Trunks >> Edit >> Options >> Codec Priority". Try moving PCMU(G.711 U-law) to the top of the list if it's not already and make another test, see if that helps at all.

 

[Mike-2408]

What network firewall are you using? Most have an option to turn off SIP ALG in the settings.

It is disabled

 

[Mike-2408]

That fact that the SIP ALG says failed doesn't mean you've got SIP ALG enabled nor is it necessarily a bad thing either. It means the test did not complete so we really don't know. Since this shouldn't affect audio quality though, I don't think you should dwell on this for now.

If this only happens for external calls, I'd also recommend checking the codecs set on the SIP Trunk in "SIP Trunks >> Edit >> Options >> Codec Priority". Try moving PCMU(G.711 U-law) to the top of the list if it's not already and make another test, see if that helps at all.

This is what I have now

 

[Mike-2408]

What are my possibilities? I am out of opinions.

Receiver sounds crystal clear, but 3cx sound to the the Receiver is horrible

 

[leejor]

Have you confirmed, in the Activity Log, that the same Codec is used, from the set and the trunk? That 3CX is not doing any trans-coding?

When you say GSM calls, I'm assuming you mean some mobile phones? Does this mean all mobile phones, or just some handsets, or some mobile providers? There is always the possibility of a trunking issue between your SIP provider and a particular mobile provider.

 

[ChrisC_3CX]

Since you seem to have PCMU set across the PBX as the priority what I recommend you do as quick tests is:

• With one of your mobile devices, using your SIM carrier, place an inbound call to 3CX and answer it using the 3CX Webclient. Check audio quality, and then compare it with the same call but outbound, make a call from the 3CX Webclient to the mobile number you called in before. Do you notice a difference? Which of the two has better audio?

• If the second call (outbound) has better audio than the first then it might mean that that your SIP Provider offers a different audio codec as the priority. It is usually the initiator's codec preference that gets honored so that's why I recommend placing an inbound and outbound and comparing the two. Theoretically, the Outbound call should use PCMU and the inbound whatever the SIP Provider offered, provided the SIP Trunk on your PBX supports it.

• If you can't tell if they have a difference I recommend you at least try to determine if there is a difference in audio quality for the audio going through your PBX and the audio after it went through your SIP Provider so that you can narrow it down. A very simple way to kind of do this is to perform an inbound/outbound call to your Mobile and record the call. Compare the audio you actually heard during the call to the audio you hear in the recording of your 3CX PBX. Remember, you should be checking the audio leaving your PBX (sent from the webclient) so make sure that during the make it clear which is which. It might be best to have someone else use the 3CX Webclient so that you can focus only on the audio reaching the mobile(external number).

Hope this helps!

 

[Mike-2408]

Since you seem to have PCMU set across the PBX as the priority what I recommend you do as quick tests is:

• With one of your mobile devices, using your SIM carrier, place an inbound call to 3CX and answer it using the 3CX Webclient. Check audio quality, and then compare it with the same call but outbound, make a call from the 3CX Webclient to the mobile number you called in before. Do you notice a difference? Which of the two has better audio?

• If the second call (outbound) has better audio than the first then it might mean that that your SIP Provider offers a different audio codec as the priority. It is usually the initiator's codec preference that gets honored so that's why I recommend placing an inbound and outbound and comparing the two. Theoretically, the Outbound call should use PCMU and the inbound whatever the SIP Provider offered, provided the SIP Trunk on your PBX supports it.

• If you can't tell if they have a difference I recommend you at least try to determine if there is a difference in audio quality for the audio going through your PBX and the audio after it went through your SIP Provider so that you can narrow it down. A very simple way to kind of do this is to perform an inbound/outbound call to your Mobile and record the call. Compare the audio you actually heard during the call to the audio you hear in the recording of your 3CX PBX. Remember, you should be checking the audio leaving your PBX (sent from the webclient) so make sure that during the make it clear which is which. It might be best to have someone else use the 3CX Webclient so that you can focus only on the audio reaching the mobile(external number).

Hope this helps!

My SIP Provider offers a different audio codec and it is set as similar to the 3CX

I dont know if i should do this test or since i have these records set in the SIP provider so the problem somewhere else ?


my internet speed is 500 Mbs for downloads and 100Mbs for uploads, i cant tell what is the problem as i hear the person who is using the mobile crystal clear but they dont hear me properly, i am in most of my test using the android 3cx App sometimes the webclient results are same

 

[ChrisC_3CX]

i cant tell what is the problem as i hear the person who is using the mobile crystal clear but they dont hear me properly, i am in most of my test using the android 3cx App sometimes the webclient results are same

Since codecs are probably the same, I recommend you test the last point. Before doing so however, I recommend at least checking the bad audio for your self. Have you not tested an external call on your PBX to confirm the reported issue? If not I might suggest doing so and then proceeding to compare the audio with that of a recording that took place on the PBX. If the difference is apparent then at least you'll be able to eliminate the PBX from the equation.

 

[Mike-2408]

Since codecs are probably the same, I recommend you test the last point. Before doing so however, I recommend at least checking the bad audio for your self. Have you not tested an external call on your PBX to confirm the reported issue? If not I might suggest doing so and then proceeding to compare the audio with that of a recording that took place on the PBX. If the difference is apparent then at least you'll be able to eliminate the PBX from the equation.

Yes, I am doing the tests myself, If the calls 3cx to 3cx i.e extension 102 calling extension 205 audio is perfect

it's only when calling from 3cx to a mobile number with SIP provider (SIM card) i.e extension 205 calling an outbound mobile number.

The person using the mobile will not hear properly voice will kind of not clear kind of annoying.

This is happening in both cases outbound calls and inbound calls same scenario.

One more thing to add not all calls quality is the same, it varies, some are okay and some are bad very rare cases calls they get clear

 

[ChrisC_3CX]

Yes, I am doing the tests myself, If the calls 3cx to 3cx i.e extension 102 calling extension 205 audio is perfect

it's only when calling from 3cx to a mobile number with SIP provider (SIM card) i.e extension 205 calling an outbound mobile number.

The person using the mobile will not hear properly voice will kind of not clear kind of annoying.

I have you heard the recording for the same call too? Is there a difference in quality? If yes, you might actually want to consider reaching out to the SIP Provider because it sounds like the audio is degrading after it leaves your PBX.

If you want to go a little deeper before contacting the SIP Provide you can actually analyze the audio leaving your PBX up to your network's firewall. You would have to somehow capture that traffic (maybe your firewall ahs this feature) and then check the RTP streams of the call as described in our Troubleshooting guide(Slide 11-12).