Re: [Flexradio] The inherent muddiness of typical amateur transceiver
audio without EQ Any thoughts? Edwin MarzanAB2VW According to hams on both sides of the issue, bandwidth is both the problem and the cure, but you can't argue with the modern science of sound, based on almost 80 years of solid research since those outdated telephone studies were created: By extending telephone bandwidth to 7 kHz and beyond, it is clear that one can markedly reduce fatigue, improve concentration, and increase intelligibility. It is also clear that this improvement is even more significant in real-world room situations, where the sound is often degraded by reverberation, projector or air conditioner noise, accented speech, and other acoustic problems that are encountered in business telephony. Additionally, extending telephone bandwidth below 300 Hz brings a significant increase in presence and realism. In his 1938 paper discussing the bandwidth of the telephone system, ATT's Inglis noted that, 'Frequency limitation is essentially an economic one, subject to change as conditions change.' Here in the twenty-first century, economics and conditions have changed as Inglis predicted, and modern telephony is now in a position to deliver on the promises of wider bandwidth and clearer speech. http://www.polycom.com/common/documents/whitepapers/effect_of_bandwidth_on_speech_intelligibility_1.pdf That said, everyone knows wider bandwidths should not be employed on very crowded amateur bands, nonetheless, the key to intelligibility and fidelity is b a n d w i d t h. About 8 KHz is super and 6 KHz is very good. When transmitting through a 3 KHz filter, some kind of EQ is necessary to relieve muddiness, unless the microphone element attenuates the low end dramatically, beginning at about 150 Hz and as long as it has a corresponding rise of about 6 dB at about 2 KHz. Bob Heil knows this and his mic's are designed accordingly. The EQ built into the PowerSDR software does a great job. If the next hardware edition of Flex-SDR has a preamp and 48v phantom power, I'm there. _ Instantly invite friends from Facebook and other social networks to join you on Windows Live™ Messenger. https://www.invite2messenger.net/im/?source=TXT_EML_WLH_InviteFriends ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] The inherent muddiness of typical amateur transceiver
I apologize in advance for getting sucked into this hot topic. I think there is merit to both side of the argument, but I think the future must be developing digital modes that will allow digital voice with a natural sounding frequency response. In other words we need to cram 6Khz of audio (or more) within a 3Khz (or less) worth of RF spectrum. This is experimentation - development - that we need. I've never heard my grandmother say it was an experiment when she turned the treble and bass knobs on her car's stereo. -Scott, WU2X On 6/3/08, Brian C [EMAIL PROTECTED] wrote: That said, everyone knows wider bandwidths should not be employed on very crowded amateur bands, nonetheless, the key to intelligibility and fidelity is b a n d w i d t h. ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] The inherent muddiness of typical amateur transceiver
Not that it matters, but the 92/93 mentioned below really should be 02/03. My, how time flies! - Jeff Jeff Anderson wrote: Interestingly, one of the primary reasons why the Polycom white paper (see previous postings) was written was that it was to be a sales tool to help explain to customers why they should purchase Polycom's VTX-1000 speakerphone (which was introduced sometime in the 92/93 time-frame, but I've forgotten exactly when). This is a speakerphone which, using encoding, compresses 7 KHz of audio into the existing 3 KHz spectrum of an analog phone line. - Jeff, k6jca P.S. 7 KHz audio sounds significantly more natural when compared to standard POTS (Plain Old Telephone System) bandwidth audio. Scott McClements wrote: I apologize in advance for getting sucked into this hot topic. I think there is merit to both side of the argument, but I think the future must be developing digital modes that will allow digital voice with a natural sounding frequency response. In other words we need to cram 6Khz of audio (or more) within a 3Khz (or less) worth of RF spectrum. This is experimentation - development - that we need. I've never heard my grandmother say it was an experiment when she turned the treble and bass knobs on her car's stereo. -Scott, WU2X On 6/3/08, Brian C [EMAIL PROTECTED] wrote: That said, everyone knows wider bandwidths should not be employed on very crowded amateur bands, nonetheless, the key to intelligibility and fidelity is b a n d w i d t h. ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] The inherent muddiness of typical amateur transceiver
Interestingly, one of the primary reasons why the Polycom white paper (see previous postings) was written was that it was to be a sales tool to help explain to customers why they should purchase Polycom's VTX-1000 speakerphone (which was introduced sometime in the 92/93 time-frame, but I've forgotten exactly when). This is a speakerphone which, using encoding, compresses 7 KHz of audio into the existing 3 KHz spectrum of an analog phone line. - Jeff, k6jca P.S. 7 KHz audio sounds significantly more natural when compared to standard POTS (Plain Old Telephone System) bandwidth audio. Scott McClements wrote: I apologize in advance for getting sucked into this hot topic. I think there is merit to both side of the argument, but I think the future must be developing digital modes that will allow digital voice with a natural sounding frequency response. In other words we need to cram 6Khz of audio (or more) within a 3Khz (or less) worth of RF spectrum. This is experimentation - development - that we need. I've never heard my grandmother say it was an experiment when she turned the treble and bass knobs on her car's stereo. -Scott, WU2X On 6/3/08, Brian C [EMAIL PROTECTED] wrote: That said, everyone knows wider bandwidths should not be employed on very crowded amateur bands, nonetheless, the key to intelligibility and fidelity is b a n d w i d t h. ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] The inherent muddiness of typical amateur transceiver audio without EQ
Ed, Most microphone need some help, on the lower end. You can use the internal EQ, the 3 band is usually sufficient, but if you use the 10 band, you might try pulling down the 125 and 250 range, usually right around 160 is where most of the muddy sound comes from. Also try brining up the low cutoff of the the transmit filter, bring it up to 100 or even 120 to see if that helps. You might also try some of the default transmit profiles in the WEB 1.10.4 version, maybe the PR781 transmit profiles would help. 73, Dudley WA5QPZ Edwin Marzan wrote: Greetings all, A couple of days ago I used my Heil PR20 to record a voice over for a video I was working on. When I played back the recording I was shocked to hear how clear and natural my voice sounded with the PR20. There was no EQ or processing applied to the audio, just the mike plugged straight into my Edirol FA66 sound card and played back into a decent pair of computer speakers. The same mike when used with my SDR-1000 does not give anywhere near the same results. Without heavy equalization using PowerSDR I have been described as sounding like pillows were placed over the mike. I was thinking that perhaps this wasn't a good selection for my SDR-1000. After hearing my recording for the voice over I'm thinking differently. Isn't it the job of the microphone to reproduce the sound as close as possible to the source as it did during the recording? I figured as a baseline my SDR1000 should sound clear without muddiness before equalization is applied. The EQ in my view should be used as an enhancement to the audio or in certain cases to make up for the deficiencies of a poorly designed microphone. So, my mike appears to be more than adequate for audio applications, why does it require massive EQ to sound decent as a transmitter audio source? Does it have anything to do with transmitter bandwith, etc? I'm thinking of purchasing the W2IHY boxes but if I was only able to get the audio to sound as good as the mike reproduces it (without EQ) I would be a happy camper. Still love the radio, though! Any thoughts?Edwin MarzanAB2VW _ E-mail for the greater good. Join the i’m Initiative from Microsoft. http://im.live.com/Messenger/IM/Join/Default.aspx?source=EML_WL_ GreaterGood ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/ -- 73, Dudley WA5QPZ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] The inherent muddiness of typical amateur transceiver
On 6/3/08, Brian C [EMAIL PROTECTED] wrote: That said, everyone knows wider bandwidths should not be employed on very crowded amateur bands, nonetheless, the key to intelligibility and fidelity is b a n d w i d t h. Hi all, Actually, IARU recommends max. bandwidth of 2700 Hz on ham bands below 28 MHz. If you obey the rules and don't want to drown the information content of your transmission into the mud, you better equalize your signal in a smart way. I apologize for referring again to these two old and good articles that every phone (SSB) operator should read and understand: http://kotisivu.dnainternet.net/ahti/sdr-1000/filtclip.pdf http://kotisivu.dnainternet.net/ahti/sdr-1000/speechproc.pdf Of course those articles discuss analog signal processing, but the same ideas apply to the DSP radios as well - actually much better. Study the TX equalizer and compressor setup possibilities of PowerSDR of Flex and K3 of Elecraft. It is really a pity that the both manufacturers have not given any recommended (default) SSB equalizer settings along the principles discussed in the given articles. Ahti OH2RZ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
[Flexradio] The inherent muddiness of typical amateur transceiver audio without EQ
Greetings all, A couple of days ago I used my Heil PR20 to record a voice over for a video I was working on. When I played back the recording I was shocked to hear how clear and natural my voice sounded with the PR20. There was no EQ or processing applied to the audio, just the mike plugged straight into my Edirol FA66 sound card and played back into a decent pair of computer speakers. The same mike when used with my SDR-1000 does not give anywhere near the same results. Without heavy equalization using PowerSDR I have been described as sounding like pillows were placed over the mike. I was thinking that perhaps this wasn't a good selection for my SDR-1000. After hearing my recording for the voice over I'm thinking differently. Isn't it the job of the microphone to reproduce the sound as close as possible to the source as it did during the recording? I figured as a baseline my SDR1000 should sound clear without muddiness before equalization is applied. The EQ in my view should be used as an enhancement to the audio or in certain cases to make up for the deficiencies of a poorly designed microphone. So, my mike appears to be more than adequate for audio applications, why does it require massive EQ to sound decent as a transmitter audio source? Does it have anything to do with transmitter bandwith, etc? I'm thinking of purchasing the W2IHY boxes but if I was only able to get the audio to sound as good as the mike reproduces it (without EQ) I would be a happy camper. Still love the radio, though! Any thoughts?Edwin MarzanAB2VW _ E-mail for the greater good. Join the i’m Initiative from Microsoft. http://im.live.com/Messenger/IM/Join/Default.aspx?source=EML_WL_ GreaterGood ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
