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All studio and professional grade monitors in general have analog inputs (TRS/XLR/RCA etc...). High end monitors have the shortest internal cable run to reduce loss of quality yet this is only a tiny fraction of the total cable run from the DAC. Why don't monitors have digital input all the way up to the internal amplifier. Digital-analogue conversion could take place a few centimetres from the driver. Why couldn't Powered monitors have optical input? Optical cables are not more expensive than good quality analog cables and there is no reason DAC's couldn't output SPDIF?

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  • Why not go all the way and use RF links - bluetooth is cheap, so is wi-fi - get rid of the signal cable completely. – Andy aka Sep 28 '13 at 17:37
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    Wireless is completely different and is not the next step in signal transmission. It has too many drawbacks. I am not talking about transmission medium but rather digital over analog transmission. – DominicM Sep 29 '13 at 18:47
  • My day job designing radios (some of the time) biases me to point out that "cable", carrying analogue or digital will be surpassed by radio in powered speakers. They have the "juice" at the receiving end (1), the size to accomodate complex antennas (2) and the sort of price to "hide" the cost of a decent RF module (3). Apart from analogue, digital bitstreams (whether optical or over copper) are likely to reinvent themselves and bring obsolescense. The same could happen to radios but they have one less component in the system, namely the cable. Cable tends to match the technology. – Andy aka Sep 29 '13 at 20:09
  • Some of what you said went over my head but the way I see it RF is only a convenience of cable free set-up - not something important for studio use. Then there's interference concerns for both audio signal and other equipment. Overcrowding would also be a huge issue when you can have 8 monitors for 7.1 set-up and then there's microphones etc... As far as RF surpassing cable, I don't see how that could be true, cable is generally far more reliable and less prone to interference. Optical cable is immune to interference altogether. – DominicM Sep 29 '13 at 23:44
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    Some of them do! These JBL speakers, for example. I could only speculate as to why this isn't more common. – Warrior Bob Sep 30 '13 at 18:06
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I think the answer is that they're looking to have the cleanest signal path.

The introduction of a DAC is just one more link in the chain, and when the chain is only as strong as the weakest link, the fewer links, the better.

Also, high-end DACs are an industry unto themselves. High-end monitor companies focus on the mechanical properties of the speaker, the clean signal path, etc. To include a DAC is to relinquish part of the signal path to another company.

  • I haven't considered the quality of DAC'. You could have replaceable DAC modules in the monitor though, that would be sweet. – DominicM Sep 29 '13 at 18:42
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    The answer is correct - since DACs cost money and there's little market for this (although there are models with digital inputs). However, this has nothing to do with the 'cleanest path'. Digital transmission over cables is as clean as it can get - any centimetre of an analogue cable will degrade the sound, not so for digital ones. Digital speaker connections will also prevent ground loops. So I don't think 'cleanest' is the right term. – Izhaki Sep 30 '13 at 18:33
  • @Izhaki, Perhaps you are correct. In that case, it would just boil down to the high-end DACs being modular, and outputting the analog signal to do with as you please. – JoshP Sep 30 '13 at 18:55
  • Yeah - modularity is often a good thing. Although this raises an interesting question - does the quality of high-end ADCs is being degraded by analogue cables to an extent that justifies (quality wise) DAC inside an active speaker? It may well be the case! – Izhaki Sep 30 '13 at 19:02
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    Jitter is actually caused by an erratic clock. Although most people associate it with the distortion (clicks) cause by unresolved clocks, which I believe is what you are talking about. And yes - both jitter and unresolved clocks will degrade the quality of the digital audio, but this is not an issue of transmission - the cables themselves (the optical ones at least) virtually give out what comes in (within physical limitation that are practically never exceeded in normal setups). – Izhaki Oct 1 '13 at 16:34
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Mostly because of preference. Most people prefer to be able to choose an amp they like with monitors they like. Keeping the parts separate also makes maintenance easier. There may also be concerns about the power of the amp interfering with the speaker some or vice versa, though I'm not sure if this would really make a significant difference.

The long and short of it though is that powered cable runs don't really matter all that much. You can't pick up much noise after amplification because the signal floor overpowers most ambient occurrences. The short runs of cables inside I think is more a marketing gimmick rather than something that actually matters.

So simply, it doesn't matter that much if it is internal or not, as long as it is a short analog run to the amp and decent enough quality speaker wire is used. It's more convenient and more maintainable to have the amp and speakers separate, so that's what is done.

  • I was mainly thinking of powered monitors. Main advantage would be the price since analog cables and other components are more expensive and prone to signal alteration than digital ones. – DominicM Sep 29 '13 at 18:45
  • @DominicM - I don't know many people that use powered monitors in their studio. If I was going to use a powered monitor, I'd personally want to send it digital signal as there would be no real advantage as long as it had a decent quality DAC. – AJ Henderson Sep 29 '13 at 18:46
  • Well, I am no pro that's for sure but any studio monitors I come across all seem to be powered. Mackie, KRK, Genelec all carry powered monitors in their studio range. Don't know if it's better just seems like the norm to me. – DominicM Sep 29 '13 at 18:50
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    This is the correct answer. Even the most high-end monitors will still influence the sound much stronger through their mechanical characteristics than any properly designed analogue electrical connection does, and the same goes for DACs. So it really can't matter significantly quality-wise whether you drive the monitors with digital or analogue signals. – leftaroundabout Oct 1 '13 at 15:59
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    @leftaroundabout True, but let's not forget that by removing analog components historically meant more affordable higher end equipment. Also just because one part of the system is more important doesn't mean that other less impactful parts should be ignored. – DominicM Oct 1 '13 at 20:27
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It's mainly because of latency. If you're recording in a studio, you'll definitely have a microphone (would be kind of hard without it). XLR microphones have several advantages over USB mics, including: 1. You can use (heaven forbid) firewire; 2. You can bypass the internal preamps (dynamic microphones usually don't even have any, but condensers have a little bit to bring it to a mic level); 3. You can use mixers, effects boards, etc. with them; etc. Most people will use XLR microphones, which are, guess what? Analog! The DAC only occurs from the PC end.

Digital-to-Analog conversion takes time, but Analog-to-Digital conversion takes significantly longer. That's because ADC requires sampling, as well as bit-matching. 16-bit bit depth = hexadecimal-to-binary, and is the smallest. Increasing the bit depth increases ADC time, while increasing sample rate does the same.

So, to answer your question, it's for zero-latency monitoring.

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