Is it possible to adjust the recording level in 3CX VM?

Discussion in '3CX Phone System - General' started by Halea, May 4, 2008.

Thread Status:
Not open for further replies.
  1. Halea

    Halea New Member

    Joined:
    Jan 5, 2008
    Messages:
    151
    Likes Received:
    0
    Greetings All:
    Lately, I've been relying quite a bit on VM message forwarding through email attachment. The system works fine although there are some delays in getting the VM kick in etc., but what I need to address first is the audio recording level issue; it's relatively low, in a noisy environment it's hard to understand the content of the audio message. I tried to playback the wav file on several computers, they all required that I turned the volume to the maximum, yet the volume wasn't sufficiently loud.
    I thought that there may be a difference whether the call came infrom a VOIP phone or over FXS; VOIP is only slightly better, so I guess the issue is in the conversion of the compressed incoming stream int a wave file. I may be mistaken, frankly I didn't think about all the steps.
    I hope one of you has tackled this issue.
    Thanks for any feedback.
    Halea
     
  2. nb

    nb Support Team
    Staff Member 3CX Support

    Joined:
    Jun 7, 2007
    Messages:
    2,127
    Likes Received:
    152
    Hi

    If you get 1 wav file left from the same phone or person in the same scenario and with the same properties and you play it on several computers, the result is always going to be the same. If the audio file is recorded badly, it will play badly. Changing machine is not going to make the quality better.

    What I am trying to say is that Voice mail recording is dependant on the hardware (phone) you are using to leave the message - or to record your voice, on the Phone's Microphone, the format and frequency plus the codec it uses.
    The best settings to save an audio file are the following: 8khz 16bit Mono PCM format (u or a)

    What phones are you using at the moment? Cisco, Aastra, Polycom, and Snom have really good mikes. You can mumble a voicemail or record a call - the quality is crystal clear. Plantronics are also very good mikes. Grandstream are also OK but at times you need to use a louder tone. However they are still understandable.

    Can you upload a sample voicemail wav file?
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  3. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    Hi Nicky:

    sure, here is the WAV file that I had uploaded before http://www.3cx.com/forums/voice-mail-wav-files-very-quiet-4539.html

    The problem is NOT the internal Gateway extension phone. These are VM messages that are left from external PSTN lines. In order to play those WAV files, you need to crank up the volume SO much, that the next windows system sound blows the speakers off your desk.

    If there was a "per provider" setting where we could define a "boost" volume for WAV files, then we could normalize the recording volume for calls from different sources so that it has the same volume as other windows sounds.

    Best Regards,
    Andy
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  4. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    Andy,

    Could you please ask your VoIP provider or PSTN gateway manufacturer "how to resolve this issue" and publish comments here?

    Thanks :)

    P.S. Your file was heard perfectly without any "next windows system sound blows the speakers off your desk" :)
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  5. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    Okay, I did that. They local phone company cannot boost the volume of calls - because their responsible ends once they hand-off the call to our equipment. They suggest that we increase the recording volume if playback is too quiet.

    I hope that helps.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  6. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    (I have edit my post. There is a "P.S.")

    Question:
    What kind of "boost" should be implemented to avoid your next post like:
    "Playing of your wav file "blows the speakers off my desk""

    Thanks

    P.S. :) our responcibility also ends at the time when wav file is delivered by e-mail. We are recommending to increase volume of playback :)
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  7. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    Hi,

    sorry for being a pest about that. I'm simply trying to satisfy repeated user complaints - and apparently, I'm not the only 3CX admin who is faced with that.

    I'm enclosing 3 sound sample that hopefully will illustrate this better.

    If you adjust your amplifier so that it plans the "Connect" or "OptMnu" files as a nice "background" sound (like one would set up their Windows sounds - audible, but not so lound that they become an annoyance), then the "voicemail" file will be VERY hard to hear.

    On the other hand, if you turn up the volume of the speaker to play the voicemail file, where it's not SO quiet that you don't have to worry about missing a word here or there, and forget to turn it back down again after listening to it, then the next time the other two sound files play they are definitely way too loud.

    I intentionally chose one of your OWN 3CX sounds to illustrate the disrepancy in volume.

    What I'm envisioning, is some sort of +/- dB setting that can be set on a per provider basis. (My observation is, that different VOIP providers and the PSTN (or maybe the gateway?) seem to have pretty consistent volume levels.)

    The fact that this issue seems to be raised by different forum members from time to time, should tell us that this issue cannot be dismissed easily.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  8. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    Sorry for being a pest :)
    Modified version of situation:
    "They local phone company cannot lower the volume of calls - because their responsible ends once they hand-off the call to our equipment. They suggest that we decrease the recording volume if playback is too loud."

    This "suggestion" may come from the same telco. (please check my "sarcastic" comment in previous post)
    I am asking for suggestions how to handle it...

    Thanks
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  9. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    >> our responcibility also ends at the time when wav file is delivered by e-mail. We are recommending to increase volume of playback <<

    I'm glad you agree with me: Your responsibility ends after the wav file is sent off by your SMTP client.

    Since the WAV file is already too quiet at the time when you are composing the MIME stream (before sending it), it is therefore in your realm of responsibility. I'm glad we got that established.

    (If the files would loose volume AFTER your SMTP transfer sent them and by the time they arrive in my inbox, then I would not be asking you to look into it)

    >> "They local phone company cannot lower the volume of calls - because their responsible ends once they hand-off the call to our equipment. They suggest that we decrease the recording volume if playback is too loud." <<

    If you are concerned about that scenario, then feel free to cover that as well. I suggested a +/- db setting. This this would already accomodate that situation.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  10. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    I don't agree :) . I'm ( partially ;) ) agreeing with telco: It is up to your system to provide acceptable level of playback volume. Content is delivered as is. Do you have any objections? (Question: can you prove your sentence regarding "buggy" implementation of recording"?)

    Thanks :)
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  11. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    Hm - let's see. Neither I can't "prove" the "buggy" implementation of Cody's Pony Express. Yet, someone felt that it was a sensible improvement to invent the telegraph...

    Just because there something "works as intended by the programmer", doesn't mean the intended solution can't be improved once actual users work with the result. (It may be a matter of cultural difference - when we create solutions for our users, it doesn't matter if WE think it's perfect. It's the sign-off by the end user that counts.)

    If your users are telling you that the current implementation of the emailed voice mails has certain shortcomings, then I would think it's worthwhile to search for a solution. Otherwise, why would you work on version 6 - just to fix bugs, or to add improvements?

    Since your system creates the WAV file it appears to be a logical point in time where the WAV settings could be manipulated.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  12. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    Ok.
    You don't have objections to telco which provides low volume (sure, you got recommendations :) ). You have objections to the implementation of wav recording http://www.3cx.com/forums/voice-mail-wav-files-very-quiet-4539.html#p23801 implemented by 3CX PBX. (recomendations are in previous posts, but we are not the telco, sorry :) )

    I'm just asking you: Where is a problem and why (important note: HOW) it should be resolved by 3CX PBX?

    Thanks
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  13. Halea

    Halea New Member

    Joined:
    Jan 5, 2008
    Messages:
    151
    Likes Received:
    0
    Guys:
    I took one of my wave files and put it through an audio editing software. The content averaged -15VU recording level. I got the measurement in Volume Units so that it is easier to understand - If you ever played with preamplifiers, or amplifiers, you know what -15VU means. That's low, very low.
    Now, let's try to analyze the chain of events here: The audio stream in my system is all G711A compressed. I don't use any other codecs. And the G711A stream seems to be properly encoded since the volume through the handset is just fine with a mid-level audio setting on the phone set. But, when that audio stream gets recorded, it gets converted to a wave file, and simultaneously it becomes pretty weak.
    So, what that tells me? Either during decompression of the G711A stream or during the encodeing of the wave stream we are losing significant intensity. Both actions are performed on the computer where the 3CX software is installed and under the 3CX software control.
    Now, how is the audio format conversion being done? Well, I can only guess; I didin't write the code, but the plausible explanation is that 3CX is calling some third party library (or their own) functions to decompress the G711A stream and some direct-show functions from the Windows OS subsystem to encode it in the wave format. In the process it is supplying these functions with parameters to determine the audio level.
    The question is where these settings are coming from? Can we change them by fiddling ini files, registery settings and the like or are they hard coded in the software?
    Is there a software AGC (automatic gain control) logic somewhere if so, where are the parameters hiding?
    If my reasoning is incorrect I will appreciate some meaningful feedback from the developers as for why it is incorrect and how this thing works.
    Thanks.
    Halea
     
  14. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    >> I'm just asking you: Where is a problem and why (important note: HOW) it should be resolved by 3CX PBX <<

    Sorry, if I didn't address these two questions before:

    a) the problem is that the WAV files that are emailed are much quiter than other media files played on the same workstations of our staff (and apparently other 3CX customers).

    b) it could be resolved by allowing customers the ability to change the recording level for WAV files that 3CX creates before emailing them.

    Thanks for asking.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  15. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    Andy,

    I hope we will find a proper solution for this "problem".

    Thanks a lot for your time and interesting discussion.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  16. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    Things are little bit simpler.
    There are no AGC, no DirectShow filters, no hardcoding, no any registry setting and so on. Audio content already has "PCM, 8kHz, 16bit, mono" format.

    Let's draw an analogy with common recorders:
    1. Source of signal (volume adjustable)
    2. Receiver of signal (recording level is adjustable)
    3. recording device
    First 2 entities adjust parameters of signal which come to entity 3.

    call comes from "analogue" line
    1. telco
    2. PSTN
    3. 3CX PBX

    call comes from VoIP provider
    1. foreign source
    2. VoIP provider
    3. 3CX PBX

    Regards
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  17. Halea

    Halea New Member

    Joined:
    Jan 5, 2008
    Messages:
    151
    Likes Received:
    0
    I still don't undrstand who's converting the audio stream from the compressed format used to communicate to the wave format ("PCM, 8kHz, 16bit, mono"). I think you are programming at high level and all the steps that i mentioned are being done in the lower layers of the process, but that doesn't mean that there aren't parameters to adjust the volume. The wave stream is not prepared and send to the 3CX computer by another device. It's taking place on the computer where 3cx is installed. Even if that conversion is a single line instruction to the opearting system, it's still done under 3cx's control. How high-level or low level your process runs might matter in the sense that those parameters may be burried somewhere, maybe set by the system by default, but they exist.
    Another simple question, why is it sampled at 8KHz with 16 bits per sample in mono? Someone decided that right? It has been entered as a parameter to a function right?
    See my point?
    Halea
     
  18. SY

    SY Well-Known Member
    3CX Support

    Joined:
    Jan 26, 2007
    Messages:
    1,825
    Likes Received:
    2
    Answer is simple:
    You can dig sligtly more (not only on high level ;) ) and find that all (almost all to be honest) codecs work exact with "PCM, 8kHz, 16bit, mono".
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  19. Halea

    Halea New Member

    Joined:
    Jan 5, 2008
    Messages:
    151
    Likes Received:
    0
    Stepan,
    You didn't answer my question about who does the format conversion. My question about the wave stream's format was just to illustrate my point that somehow, someone, somewhere defines which parameters to use.
    Two more questions to you:
    1- Are you a software engineer?
    2- Are you a native speaker of the english language?
    Halea
     
  20. Andy Schmidt

    Andy Schmidt New Member

    Joined:
    Apr 3, 2008
    Messages:
    118
    Likes Received:
    0
    I my country, that technology works different:

    1. Source of signal (Emits sound/pressure waves. Volume MAYBE "adjustable", but I can't make the birds in the trees sing louder!?)
    2. Receiver of signal (Converts sound waves into electrical signal, e.g.: Microphone - usually NOT adjustable)
    3. Recording device (Transcribes electrical signal onto store media, converting it to magnetic field, light signal, etc. Has "recording volume" control!)

    The only item that has a recording volume control (or has an "automatic" level control that boosts recording level for quiet input!) is the THIRD entity, which is what 3CX is missing.

    :idea: Now I understand why you are having such a hard time relating to this request. It appears in your country, the birds have little "dials" to make them sing louder. The tiny microphones have built in amplifiers and slider controls that boost electrical output - and that's why they build your recording devices without any adjustments or automatic recording levels.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
Thread Status:
Not open for further replies.