It's NOT a microphone issue. It's the small bit processing. I have been in Pro sound for most of my life. Their is NO WAY to get any quality at 8bit. This is unexceptionable to me! I rather listen to all the QRM and QRN in the world with analog. I am very surprise that their are not more people that feel this way. The bit rate has to be at lest 28bit to starting sounding acceptable. John ========================================
--- In [email protected], "Ted Wrobel" <twro...@...> wrote: > > There are likely two possible areas for improvement and one where > improvement is likely impossible. > > Some radios seem to have better transmit audio than others. Many people find > the IC-2200 very good while many people find the ID-880 very bad. > Possible the receive audio could also be improved by some additional audio > processing. > > Much of the "poor" quality in DStar can be attributed to the AMBE Vocoder. > This is a very complex algorythm that converts a high bit-rate voice data > stream into a very low bit-rate data stream. By its very nature this is a > lossy process. Removing bits must reduce the information content of the > data. AMBE attempts to maximize the bit-rate while maintaining 'acceptable' > audio quality. Some people may find the resulting sound unacceptable. Much > like the battles over vinyl vd CD vs MP3 and tubes vs solid state in the > music world, some ears are very sensitive to the aural content while others > are quite insensitive. > > In a search to find a better sound for my 880, I contacted Bob, AB5N, who > sells upgrades to a vatiety on ham microphones hoping he could provide a > solution. below is his response. I hope it helps explain the problem. > > 73, > Ted > > W1GRI > > Ted- > > We have a conundrum here. Most people buy the ID-880H to use it on D-Star. > > Otherwise they would just buy a less-expensive rig. > > D-Star is a extremely compressed digital voice mode. They don't want to > digitize any audio that isn't > directly responsible for intelligibility. That passband is 300-3000... the > old telephone response. > Any audio that is outside that range would just be "wasting bits" encoding > sound that does not > help you understand what is being said. So, the mic audio is tailored > narrowly to that passband > for D-Star in the radio. Problem is, on FM, it sounds light at the bottom. > If it was me, I would have had separate mic EQ circuits switched in for each > mode. > > Thus, if we change the mic response curve to un-do what the mic pre-amp EQ's > are doing, D-Star will go down the drain. Digital distortion is horrible. > I've tried this experiment with my ID-800. > I had to remove the new element and go stock again. > > As well, Icom engineers have always felt that their radios should have > "communications-grade audio". None of their FM radios sound as pleasing as > say a Yaesu FM mobile (totally analog radios). When you go to an Icom like a > IC-7000, it is like comparing a vinyl record with a MP3. > > So, for radios that use the 133 or 131 - which do not have D-Star, indeed my > mic element gives a very nice improvement. > > Uh oh... major storm here...tornado warnings.. I better unplug the router > and laptop. > > Hope that clears it up... I wish I could help! > > Bob-AB5N > > > > _____ > > From: [email protected] [mailto:[email protected]] > On Behalf Of n2gyn > Sent: Wednesday, September 01, 2010 14:27 > To: [email protected] > Subject: [DSTAR_DIGITAL] Re: Bit Rate? > > > > > Thank you all for you reply and comments. > Let me make myself clearer. > I would like to see the audio quality of D-Star be improved. To MY ears' > everyone sound like a robot. I thought this was due to the low bit rate. I > am NOT impressed with the digital voice mode. I want to hear a more natural > sounding voice. My telephone sounds better. > How could this be achieved if not by bit rate? > John > ==================================================== > > --- In [email protected] > <mailto:dstar_digital%40yahoogroups.com> , "Ted Wrobel" <twrobel@> wrote: > > > > Hi John, > > > > Not quite sure what you are thinking, but here is a brief overview of the > > DStar data stream. > > > > The input to / output from the data processing 'module' of the radio is a > > 9600 Baud stream - which equates to roughly 960 eight bit characters per > > second. > > > > The logic of the system digitizes the voice in and passes it to the AMBE > > Vocoder that compresses the data stream - a lot. > > > > It is the compresion by the Vocoder that is both the strength and weakness > > of DStar. The compression makes a low data rate (and thus low bandwidth) > > possible, but it also means that the re-constituted voice is an > > approximation of the voice input. Generally the reconstructed voice is > > pretty good, and given the bandwidth it is really quite remarkable. > > > > In any case, the baud rate of the system is fixed and cannot be modified > at > > any stage of the process without making the resulting stream > unrecognizable > > to other DStar systems. > > > > Note that the data rate over the internet can be much higher, but the > chain > > from repeater controller to / from the radio is fixed for DV comms at > 9600. > > > > > > 73 > > Ted > > W1GRI > > > > _____ > > > > From: [email protected] > <mailto:dstar_digital%40yahoogroups.com> > [mailto:[email protected] > <mailto:dstar_digital%40yahoogroups.com> ] > > On Behalf Of n2gyn > > Sent: Tuesday, August 31, 2010 16:54 > > To: [email protected] <mailto:dstar_digital%40yahoogroups.com> > > > Subject: [DSTAR_DIGITAL] Bit Rate? > > > > > > > > > > Most radios are sent to 8bit. Can all radio's bit rate be changed? > > I believe it is the LOW bit rate that lowers the quality of d-star's > audio. > > Is there a sub menu in the radio's. Also can the repeater's rate be change > > to a higher rate? > > John > > >
