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Post by John on Nov 24, 2014 18:24:49 GMT
I had a few experiences recently that had made me think whilst USB Asynch can give you great results it eventually prevents the sound envelope from being pushed even further. I remember Stan years ago saying he was not keen on Asych as he thought from a designers point of view it was flawed and I heard a system at the weekend which is the best digital front end system I ever heard the noise floor was drastically dropped compared to the high end Transport we were comparing it with, but was using CAT 6 to send music too I was blown away but what I was hearing, even on the limit speakers I could tell I was hearing something special the sound was just so musical no matter what we threw at it.
I now now once money frees up where I will push my digital front end.
I hasten to add I still USB done right with give you very good results.
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Post by Eduardo Wobblechops on Nov 24, 2014 19:24:48 GMT
What was the front end John?
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Post by John on Nov 24, 2014 19:48:42 GMT
It was a special built PC (not for sale) going through a external soundcard
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Post by Stratmangler on Nov 24, 2014 22:11:44 GMT
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Post by Stratmangler on Nov 24, 2014 22:15:01 GMT
but was using CAT 6 to send music too I was blown away but what I was hearing, even on the limit speakers I could tell I was hearing something special the sound was just so musical no matter what we threw at it. Sounds like it uses an i2s connection en.wikipedia.org/wiki/I%C2%B2S |
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Post by Deleted on Nov 25, 2014 15:07:48 GMT
Hi SM
I2s is absolutely the medium to use for digital audio data over short distances (under 6") in fact pretty much every CD player of note uses this method to transmit PCM
Over longer distances you would need a more robust transmit carrier, a couple of manufacturers use I2s over HDMI with a lot of redundant connections.
Sending audio data via I/P over Ethernet is (imho) a far more accurate method of data transfer with inherently low latencies and the ability to transmit over greater distances with much lower losses as well as up to 1Gps.
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Post by MartinT on Nov 25, 2014 17:10:30 GMT
Agreed - audio over Ethernet sounds a lot better than audio over USB. Generally, and especially in the case of low CPU power devices like the Raspberry Pi and Logitech Touch, USB takes too much central processing.
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Post by Deleted on Nov 25, 2014 18:20:56 GMT
USB also generates too much reciprocal mother board electrical interference which is counterproductive for quality audio (imho).
Taking things a step further having a separate LAN pathway specifically for the audio data derived from a dedicated bespoke source takes this to another level of data isolation away from the inherently 'dirty' electrical environment of a PC.
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Post by John on Nov 25, 2014 18:28:48 GMT
The more you can lessen interference on the motherboard the better
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Post by Deleted on Nov 25, 2014 18:39:08 GMT
The more you can lessen interference on the motherboard the better It certainly helps John, though quality PC audio is a multi pronged look at all the aspects of how the audio data signal is generated, passed through the PC and transmitted from it. It is a game of patience and understanding plus thinking outside the box a little. Those further reworkings have proved thus more positive as well. |
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Post by yomanze on May 28, 2015 0:18:21 GMT
I don't think PC audio is too complicated, and anyone can get a USB to SPDIF front end that'll beat CD transports. It did take some time though IMHO, the HagUSB was great at the time for USB to SPDIF, but not near a good CD transport. IMHO the simple criteria are:
1. Optimised software that does proper OS management like JRiver, which saves a lot of config tweaky time;
2. Galvanically isolated USB power supply i.e. the USB is not powered by the host;
3. Invest most in a decent USB to SPDIF converter, which should be asynchronous as they sound better than adaptive.
4. Done enough ABX tests to quantify why I prefer lossless files, and they are critical in a HiFi, not so in a car system or kitchen radio!
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Post by Pinch on May 28, 2015 7:44:40 GMT
Agreed - audio over Ethernet sounds a lot better than audio over USB. Generally, and especially in the case of low CPU power devices like the Raspberry Pi and Logitech Touch, USB takes too much central processing. Interestingly, I found that - once I'd overcome the stuttering problems with a little overclocking - I had noticeably better results over USB than with the Digi+, though still not quite as good as my PC (but pretty close). That's not to suggest that USB is not without its limitations, but as John said, it's certainly capable of giving satisfactory results. It's difficult to say anything more general than that though - the USB interfaces I've used have varied quite a lot in performance. |
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Post by Deleted on May 28, 2015 8:30:10 GMT
Pinch have you experimented between USB 2 and high speed USB 3 interfaces at all?
They is some mileage to grained there to.
Have been working away on some new playback software and routing methods and new sample frequency, yesterday after six months of what at times seemed a pointless exercise in futility finally slotted into place.
Have achieved a rock steady audio network delivery latency of 23usec and the results are very pleasing.
Now just have to integrate the playback software with an intuitive GUI.
In comparison with the replay you spent time with on your last visit John, that now seems mechanical, contrived and noisy!
An exciting journey has now started
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Post by MartinT on May 28, 2015 8:38:43 GMT
Tony, unfortunately the Raspberry Pi 2 does not have a USB3 port.
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Post by Pinch on May 28, 2015 8:44:41 GMT
No I don't think I've used a USB 3 interface - I did most of my experimenting a few years ago, and USB 1/2 seemed to be the standard then. This is the interface I use currently, with the PurePower battery module for the clocks and then a separate PSU for the processor. Congrats on the breakthrough! |
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Post by Deleted on May 28, 2015 9:06:56 GMT
Hi Guys
No USB2 imho is superior for sound, the high speed USB3 is far nosier I feel.
In fact by turning off the USB 3 internals and using the legacy USB even in a stock PC the difference is clearly audible.
Isolating the 5Vdc supply, improving the clocking structure and giving independent clean power for the processors is a very logical step and will result in a much lower noise floor, improved detail retrieval, much less digital edge and a greater sense of fluidity to the sound.
I also found spending time on digital grounding also paid dividends to. Have you fitted upgraded regulators to the clock circuit Pinch
I have inadvertently thrown up a unexpected surprise, I can now hear the volume control working in pre amplifier and that is supposed to have a s/n of -144dB lol
Going to try the C600 later see how low this noise floor really is!
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Post by John on May 28, 2015 9:26:41 GMT
Be good to have a listen to the server sometime Tony
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Post by Pinch on May 28, 2015 10:02:59 GMT
Have you fitted upgraded regulators to the clock circuit Pinch Heh, no - way beyond my limited field of expertise; I did fit rubber feet to casing, but that's about my limit  |
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Post by Deleted on May 29, 2015 12:20:50 GMT
Have you fitted upgraded regulators to the clock circuit Pinch Heh, no - way beyond my limited field of expertise; I did fit rubber feet to casing, but that's about my limit If you you wish to go this route I am happy to install theses for you no problem. |
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