> 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
