Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
Hi Mark, Interesting! Thank you for the update! Some time ago I have prepared a branch that emulates the gain change during vinyl scratching: https://github.com/mixxxdj/mixxx/pull/602 I have used a frequency independent gain-by-speed curve picked from a Serato vinyl. https://bugs.launchpad.net/mixxx/+bug/1450665/+attachment/4388671/+files/speed-gain.ods Thinking about this again, I wonder if this does already include the RIAA curve. A double speed for a 1 kHz signal means approx. -2.5 dB in the RIAA curve (ratio 0.75) Actually the measured ratio is approx 1.4 which includes the RIAA negative gain plus a positive gain due to the increased speed. Maybe the non straight curve form of RIAA is negligible or selves- compensating due to the the mechanical effects in a speeding vinyl .. What do you think? Kind regards, Daniel Am 05.11.2016 um 20:50 schrieb Mark Hills: > The timecode decoder is almost totally self-calibrating; adding an RIAA > preamp will have almost no effect on the decoding. > > The only reason I can think to implement one in Mixxx is if you want to > use your software preamp to listen to regular vinyls (not timecode) > > Also keep in mind that when scratch etc. the Serato 1KHz sine wave then > appears at all sorts of frequencies. That would make it technically > incorrect to apply an RIAA equalisation, but in practice I don't see it > making any difference. > > A more interesting side note is: to emulate a more 'correct' vinyl sound > during scratching, the playback software should not just timestretch, but > apply an inverse RIAA curve to the audio file, followed by the necessary > timestretching, followed by the RIAA curve. I have not tested how > noticable this difference would be. > > (When you scratch on a regular vinyl and turntable it shifts lots of > frequences around but the equalisation curve is left in place) > -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
On 11/05/2016 02:50 PM, Mark Hills wrote: > The timecode decoder is almost totally self-calibrating; adding an RIAA > preamp will have almost no effect on the decoding. > > The only reason I can think to implement one in Mixxx is if you want to > use your software preamp to listen to regular vinyls (not timecode) Thanks for clarifying. > > A more interesting side note is: to emulate a more 'correct' vinyl sound > during scratching, the playback software should not just timestretch, but > apply an inverse RIAA curve to the audio file, followed by the necessary > timestretching, followed by the RIAA curve. I have not tested how > noticable this difference would be. > > (When you scratch on a regular vinyl and turntable it shifts lots of > frequences around but the equalisation curve is left in place) > Interesting idea. I think it's worth trying and comparing how it sounds. -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
Hi Be, the ground wire of some turn table can be also make a big difference to eliminate the 50 Hz power supply noise. I am not 100 % sure, but the circuit in front of the op-amps are most likely EMI protection circuits. They should not have a notable impact to the sound. Kind regards, Daniel Am 31.10.2016 um 21:18 schrieb Be: > > On 10/31/2016 01:07 PM, Sean M. Pappalardo - D.J. Pegasus wrote: >> >> On 10/31/2016 10:50 AM, Be wrote: >>> Well, if it works with the Maya44 USB as the link Daniel posted reports, >>> I don't know why it wouldn't work with a higher quality sound card. >> Oh then it likely will. (I didn't visit that link. Did it say absolute >> mode works?) >> >>> I suppose inverse RIAA EQ >>> could have that effect, but I'm doubtful. >> I believe it does, since it attenuates HF instead of just boosting the >> full range. > I looked up some block diagrams of phono preamps, and indeed some of > them have the RIAA EQ before the op amp, but others do not. According to > one source, it's best to split the high frequency attenuation and low > frequency boost into two stages and use two op amps: > http://www.learningelectronics.net/circuits/riaa-phono-preamplifier.html > That's not because of noise picked up along the cable, it's to minimize > high frequency noise from minute scratches on the record. > > While this may matter for maximum sound quality for passthrough mode or > digitally recording vinyl records, if the Maya44 USB works, it doesn't > seem necessary for timecode control. > > I opened up my Rane SL2 (which does not have a Linux driver) and it > looks like there is some processing before the op amp. I'm not sure > whether that is performing the RIAA EQ. Maybe someone more knowledgeable > about electrical engineering could provide some insight. Here's a photo > of it: https://s21.postimg.org/mkql7q2o7/sl2_input.jpg > On a side note, there's no true analog passthrough on that device. When > operating in stand alone mode with an AC adapter and no USB connection, > the signal still gets converted to digital and back again. This has been > confirmed by Rane (http://dj.rane.com/forums/viewthread/30/ ) > >>> Ah, okay. That doesn't mean that two microphone inputs couldn't work though. >> Of course but the other thing users would need to be aware of is if >> their TTs output line level, that can't be used with a mic-level input >> at all. (It is way too high and will massively distort.) > Sure, but they need to be aware of that anyway to understand whether to > use a phono preamp. > >> Starting to see why we just point out the best practice in the >> documentation? :) It causes the least confusion and is easiest to >> support. (Trying out alternatives is always welcome and goes without >> saying.) >> > Yes, documentation should make best practice clear but it shouldn't > leave out detail that confuses users trying to use unusual setups. > > -- > Developer Access Program for Intel Xeon Phi Processors > Access to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today. http://sdm.link/xeonphi > ___ > Get Mixxx, the #1 Free MP3 DJ Mixing software Today > http://mixxx.org > > > Mixxx-devel mailing list > Mixxx-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
On 10/31/2016 01:07 PM, Sean M. Pappalardo - D.J. Pegasus wrote: > > > On 10/31/2016 10:50 AM, Be wrote: >> Well, if it works with the Maya44 USB as the link Daniel posted reports, >> I don't know why it wouldn't work with a higher quality sound card. > > Oh then it likely will. (I didn't visit that link. Did it say absolute > mode works?) > >> I suppose inverse RIAA EQ >> could have that effect, but I'm doubtful. > > I believe it does, since it attenuates HF instead of just boosting the > full range. I looked up some block diagrams of phono preamps, and indeed some of them have the RIAA EQ before the op amp, but others do not. According to one source, it's best to split the high frequency attenuation and low frequency boost into two stages and use two op amps: http://www.learningelectronics.net/circuits/riaa-phono-preamplifier.html That's not because of noise picked up along the cable, it's to minimize high frequency noise from minute scratches on the record. While this may matter for maximum sound quality for passthrough mode or digitally recording vinyl records, if the Maya44 USB works, it doesn't seem necessary for timecode control. I opened up my Rane SL2 (which does not have a Linux driver) and it looks like there is some processing before the op amp. I'm not sure whether that is performing the RIAA EQ. Maybe someone more knowledgeable about electrical engineering could provide some insight. Here's a photo of it: https://s21.postimg.org/mkql7q2o7/sl2_input.jpg On a side note, there's no true analog passthrough on that device. When operating in stand alone mode with an AC adapter and no USB connection, the signal still gets converted to digital and back again. This has been confirmed by Rane (http://dj.rane.com/forums/viewthread/30/ ) >> Ah, okay. That doesn't mean that two microphone inputs couldn't work though. > > Of course but the other thing users would need to be aware of is if > their TTs output line level, that can't be used with a mic-level input > at all. (It is way too high and will massively distort.) Sure, but they need to be aware of that anyway to understand whether to use a phono preamp. > Starting to see why we just point out the best practice in the > documentation? :) It causes the least confusion and is easiest to > support. (Trying out alternatives is always welcome and goes without > saying.) > Yes, documentation should make best practice clear but it shouldn't leave out detail that confuses users trying to use unusual setups. -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
On 10/31/2016 10:50 AM, Be wrote: > Well, if it works with the Maya44 USB as the link Daniel posted reports, > I don't know why it wouldn't work with a higher quality sound card. Oh then it likely will. (I didn't visit that link. Did it say absolute mode works?) > I suppose inverse RIAA EQ > could have that effect, but I'm doubtful. I believe it does, since it attenuates HF instead of just boosting the full range. > Ah, okay. That doesn't mean that two microphone inputs couldn't work though. Of course but the other thing users would need to be aware of is if their TTs output line level, that can't be used with a mic-level input at all. (It is way too high and will massively distort.) Starting to see why we just point out the best practice in the documentation? :) It causes the least confusion and is easiest to support. (Trying out alternatives is always welcome and goes without saying.) Sincerely, Sean M. Pappalardo "D.J. Pegasus" Mixxx Developer - Controller Specialist smime.p7s Description: S/MIME Cryptographic Signature -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
On 10/31/2016 11:28 AM, Sean M. Pappalardo - D.J. Pegasus wrote: > > On 10/31/2016 09:04 AM, Be wrote: >> Thanks for clarifying. I understand turning up the gain on an >> onboard sound card wouldn't work great, but that's not my intended >> use case. If this is where the recommendation to use a phono preamp >> comes from, it should be clarified in the documentation. > > Essentially, since most Mixxx users don't have high-end hardware and/or > want to test out VC before buying additional gear. But we've never > tested or heard reports of others trying it on higher-end gear, so we > don't really know how well it would work in practice. At best, results > will vary depending on the specific sound card and environment. (We > write the documentation to help the average user get good results with > minimal fuss, so usually only talk about best practices.) Well, if it works with the Maya44 USB as the link Daniel posted reports, I don't know why it wouldn't work with a higher quality sound card. I guess I'll have to test to confirm and clarify the manual and wiki accordingly. >> indicate these can provide 118 dB gain (trim range -96 to +22 dBu) >> with -102 dB THD+N. I believe that would be way more than adequate >> for boosting phono level to line. Of course it wouldn't provide >> inverse RIAA equalization, hence the question. > > The analog noise (coming in on the cables before the ADC) you'll get > from that much linear gain (~46dB) could still interfere with the HF > time code position signal. Noise picked up along the cable would be just as much of a problem for a Traktor Scratch A6/A10 as it would be for a MOTU Ultralite AVB, unless sound cards with phono preamps have some sort of processing before the ADC that minimizes the effect of the noise. I suppose inverse RIAA EQ could have that effect, but I'm doubtful. I'm also doubtful they EQ the signal before it goes through the op amp. >> The Mixxx manual explicitly states that microphone inputs won't work >> for timecode. Was this also in reference to onboard sound cards? If >> so, this should be clarified. > > No, it's because the time code signal is stereo while microphone inputs > are mono. Ah, okay. That doesn't mean that two microphone inputs couldn't work though. -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
On 10/31/2016 09:04 AM, Be wrote: > Thanks for clarifying. I understand turning up the gain on an > onboard sound card wouldn't work great, but that's not my intended > use case. If this is where the recommendation to use a phono preamp > comes from, it should be clarified in the documentation. Essentially, since most Mixxx users don't have high-end hardware and/or want to test out VC before buying additional gear. But we've never tested or heard reports of others trying it on higher-end gear, so we don't really know how well it would work in practice. At best, results will vary depending on the specific sound card and environment. (We write the documentation to help the average user get good results with minimal fuss, so usually only talk about best practices.) > indicate these can provide 118 dB gain (trim range -96 to +22 dBu) > with -102 dB THD+N. I believe that would be way more than adequate > for boosting phono level to line. Of course it wouldn't provide > inverse RIAA equalization, hence the question. The analog noise (coming in on the cables before the ADC) you'll get from that much linear gain (~46dB) could still interfere with the HF time code position signal. > The Mixxx manual explicitly states that microphone inputs won't work > for timecode. Was this also in reference to onboard sound cards? If > so, this should be clarified. No, it's because the time code signal is stereo while microphone inputs are mono. Sincerely, Sean M. Pappalardo "D.J. Pegasus" Mixxx Developer - Controller Specialist smime.p7s Description: S/MIME Cryptographic Signature -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
> Have you ever tried it out with a "normal" preamp? > > Gernot Of course, if I had the hardware in front of me, I'd just try it. I'm asking because I'm researching what hardware to get. On 10/31/2016 10:26 AM, Sean M. Pappalardo - D.J. Pegasus wrote: > > > On 10/31/2016 05:11 AM, Daniel Schürmann wrote: >> Mixxx already offers a digital 44 dB gain, that should be able to boots >> the phone level to line level. > > I have tried doing exactly what Be suggests. It can work in a pinch, but > it's not as reliable. Read on to find out why. > >> the Serato timecode is just a 1 kHz sine >> wave > > Not quite. The absolute position is present in a higher-frequency component. > > Simply increasing the gain that much also amplifies the (analog) noise > significantly, of which there is much inside a computer (low-quality and > integrated sound cards make it worse.) Then the "bit crushing" from so > much digital gain introduces quantization noise. Not to mention that the > longer the unbalanced phono-level signal from the stylus travels in the > physical wires between the turntable and the ADC in the sound card, the > greater the chance it has to pick up external noise. (This may be one > reason why the phono cables on the original SL-1200 and MK2 were > hard-wired: to discourage using longer ones.) > All of these noise sources can interfere with the high-frequency part of > the time code signal, causing VC to lose absolute position often (and > even relative position if any spurious noise is around the frequency of > the "carrier" wave of the control signal in use.) Thanks for clarifying. I understand turning up the gain on an onboard sound card wouldn't work great, but that's not my intended use case. If this is where the recommendation to use a phono preamp comes from, it should be clarified in the documentation. I'm looking to get a high quality MOTU Ultralite AVB and turntables and hooking up the turntables to the line inputs on the Ultralite AVB. The specifications (http://motu.com/products/avb/ultralite-avb/specs.html ) indicate these can provide 118 dB gain (trim range -96 to +22 dBu) with -102 dB THD+N. I believe that would be way more than adequate for boosting phono level to line. Of course it wouldn't provide inverse RIAA equalization, hence the question. The Mixxx manual explicitly states that microphone inputs won't work for timecode. Was this also in reference to onboard sound cards? If so, this should be clarified. > > And of course pass-through would sound horrible. > Yes, of course. I for one wouldn't really care about adding a software inverse RIAA EQ to Mixxx for this purpose because my entire music collection is digital. If I wanted to play music from a vinyl record, I'd want to record it before DJing to include it in the rest of my collection (and record it as early as possible to avoid including the degradation of vinyl that occurs with each playback). I haven't seen any requests for this feature, but if someone wants to put in the work to implement it, go for it. > The inverse RIAA EQ gives an advantage here since it boosts frequencies > above 1kHz far less than it does those below. Actually, the inverse RIAA EQ attenuates above 1 kHz and amplifies below 1 kHz. https://en.wikipedia.org/wiki/RIAA_equalization > > So it might be interesting to try gaining up the signal non-linearly > (following the inverse RIAA EQ) in software and see how it performs. But > quantization noise would still be present (though you can try shaped > dithering, increasing CPU load) so using a phono preamp is still the > best practice which is why we recommend it. > > Sincerely, > Sean M. Pappalardo > "D.J. Pegasus" > Mixxx Developer - Controller Specialist -- Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
On 10/31/2016 05:11 AM, Daniel Schürmann wrote: > Mixxx already offers a digital 44 dB gain, that should be able to boots > the phone level to line level. I have tried doing exactly what Be suggests. It can work in a pinch, but it's not as reliable. Read on to find out why. > the Serato timecode is just a 1 kHz sine > wave Not quite. The absolute position is present in a higher-frequency component. Simply increasing the gain that much also amplifies the (analog) noise significantly, of which there is much inside a computer (low-quality and integrated sound cards make it worse.) Then the "bit crushing" from so much digital gain introduces quantization noise. Not to mention that the longer the unbalanced phono-level signal from the stylus travels in the physical wires between the turntable and the ADC in the sound card, the greater the chance it has to pick up external noise. (This may be one reason why the phono cables on the original SL-1200 and MK2 were hard-wired: to discourage using longer ones.) All of these noise sources can interfere with the high-frequency part of the time code signal, causing VC to lose absolute position often (and even relative position if any spurious noise is around the frequency of the "carrier" wave of the control signal in use.) And of course pass-through would sound horrible. The inverse RIAA EQ gives an advantage here since it boosts frequencies above 1kHz far less than it does those below. So it might be interesting to try gaining up the signal non-linearly (following the inverse RIAA EQ) in software and see how it performs. But quantization noise would still be present (though you can try shaped dithering, increasing CPU load) so using a phono preamp is still the best practice which is why we recommend it. Sincerely, Sean M. Pappalardo "D.J. Pegasus" Mixxx Developer - Controller Specialist smime.p7s Description: S/MIME Cryptographic Signature -- The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
Hi, According to this post a solution without the RIAA eq should work "equal well": https://sourceforge.net/p/xwax/mailman/xwax-devel/thread/5150c184.40...@oscille.ca/ There is only the remaining issue that path-though will sound bad. Mixxx already offers a digital 44 dB gain, that should be able to boots the phone level to line level. So we may consider to add an RIAA eq to Mixxx. Unfortunately, we loose bit resolution by such a high digital gain you will use only 9 bit of your 16 bit ADC. (bit-cruscher effect) Do we have requests for it? Kind regards, Daniel 2016-10-31 9:29 GMT+01:00 Gernot Tutner : > Have you ever tried it out with a "normal" preamp? > > Gernot > > > -- > The Command Line: Reinvented for Modern Developers > Did the resurgence of CLI tooling catch you by surprise? > Reconnect with the command line and become more productive. > Learn the new .NET and ASP.NET CLI. Get your free copy! > http://sdm.link/telerik > ___ > Get Mixxx, the #1 Free MP3 DJ Mixing software Today > http://mixxx.org > > > Mixxx-devel mailing list > Mixxx-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mixxx-devel > -- The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] RIAA equalization, timecode, and preamps
Have you ever tried it out with a "normal" preamp? Gernot -- The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
[Mixxx-devel] RIAA equalization, timecode, and preamps
Mixxx documentation has long recommended using a phono preamplifier before analog-to-digital conversion for timecode vinyl control. I am questioning whether a phono preamp that undoes the RIAA equalization of vinyl records is really necessary or if any preamp that provides sufficient gain will work for timecode. Please correct me if I am misunderstanding anything here. RIAA equalization is applied to music vinyl in the process of cutting the vinyl. The equalization does not change how a DJ's manipulation of the playback of a record affects the audio signal coming out of the turntable. It is this manipulation of the playback of timecode that Mixxx interprets. Furthermore, the Serato timecode is just a 1 kHz sine wave, which happens to be where the RIAA EQ curve is flat. Even if it weren't for that coincidence, EQing a pure sine wave wouldn't matter because EQ adjusts the relative amounts of different frequencies in a signal. So, for the purposes of timecode control, RIAA EQ seems irrelevant and a turntable playing timecode could be hooked up to any sound card input that has plenty of gain. Of course, if a music vinyl was recorded through a sound card input without RIAA EQ, that EQ would have to be applied digitally after recording to make it sound good (which Audacity can do easily). -- The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
