In order to get this thread back on track, has anyone used both miniDSP and the Hypex offering? Is it a worthy upgrade given I'm single ended until I build some UcD modules later on?
I also noticed a comment earlier in the thread about the analogue input seemingly being better quality than the digital in. Anyone done a similar comparison and come to similar conclusions? What's the technical reason for this if so?
Thanks.
I also noticed a comment earlier in the thread about the analogue input seemingly being better quality than the digital in. Anyone done a similar comparison and come to similar conclusions? What's the technical reason for this if so?
Thanks.
It has been about implementing DLCP so nothing is off track. I replaced the first generation miniDSP 2+2 with a DLCP. I think the DLCP was superior. Now, miniDSP has since released a number of products that I suspect is superior to their first attempt. They now have a number of different offerings so maybe you want to specify which of them you want compared.
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That's what I'm leaning towards, but I'm planning a mock-up of the parts before ordering the front panel so will be able to check for audibility. But I have built a MiniDSP system (separate from the power amp box), and it's crammed full of circuit boards (a gutted SB2, power supplies built from Velleman kits, USB-to-Toslink device, MiniDSP, MiniDSP control board, MiniDC etc), and it sounds wonderful.
Thinking more about my original question: Assuming the USB connection from the DLCP input board to the DLCP processor board is just a straight through connection, then my question really simplifies to whether that external USB socket can have a USB hub plugged into it in order that more than one computer can connect to the devices that it presents:
- RPi/audio source to the audio device
- external PC to the control device.
I don't know enough about how USB works - can *any* USB port be multiplied by attaching a hub, or does it have to be some sort of 'USB host' that permits a hub to be connected? I'm guessing that a single downstream device (e.g. the audio device) can't be shared this way, but can the two separate downstream devices be accessed separately via a hub?
Only if they have separate physical USB connectors. USB has no facilities for multiplexing or "logical" addresses for endpoints - the connection is always assumed to be point-to point (with hubs "forking off" the connections - but it is still point-to-point between end device and hub. So a host can share multiple output devices as long as each is on it's own connector (on host or hub), but one output device can not be shared by multiple hosts.
Thank you. Ok, so that appears to rule out my idea to use the RPi as a USB audio source (connected to the DLCP audio device) while still leaving the DLCP external USB socket as a way to access the DLCP filter settings and update firmware etc.
Is there a way around that?
I guess my fallback option, assuming I decide to keep the RPi integrated within the enclosure, would be to route the USB output from the RPi to a socket on the back of the enclosure and then have a short USB link cable from there to the DLCP USB input. That way I could remove the link to connect a PC whenever I want to update the filter settings or firmware.
That's an interesting idea. There are 4 lines in the USB (data+, data-, VCC, GND), so I think a little board with 4 relays could do the trick, or 3 if GND is common. I wonder if I could use the VCC on the DLCP external USB socket to trigger the relay, so that connecting an external PC makes the relays switch over.
Oops - GND won't be common since it's the reference for VCC, and when this is provided by the external PC it won't necessarily have the same GND as the DLCP chassis. So 4 relays then. But I do think VCC and GND from the external PC can be used to switch the relays over. I'll have to buy a board and have a play.
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USB input as in audio input or for configuring and fiddling with the filters? If audio input then my recommendation is don't, the USB input on the DLCP is sub par (only supports 16 bit depth) so you are better off using optical, spdif or aes/ebu as input.
Have you ever come across any commercial recordings using a range of more than 16 bits?
Both/either - RPi internally as audio source, PC externally for configuration. I'm favouring USB because it's the only input that can be provided by the RPi without having to add a HAT, and because I'd like to keep the other inputs free for other external devices. In fact, if the relay option works then it might allow me to have the RPi connected internally but also connect another USB *source* externally (i.e. not just a configuration PC).
16-bit isn't a problem for my music collection, and likely never will be. But I'd be interested in what the DLCP's USB chip would do when presented with a 24-bit source. Would it simply ignore the lowest 8 bits, or would it be unable to do anything with it? I ask because I seem to remember that all Squeezebox hardware outputs 24-bit streams, where the lowest 8 bits are padded with zeroes when the source is 16-bit. Is that also the case with Squeezelite running on the RPi I wonder. Obviously, it won't matter if the DLCP's USB chip ignores those 8 bits of zeroes, but if the 24-bit stream won't play at all then I'd be in trouble.
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Thanks - yes, I just found this option:
-a <b>:<p>:<f>:<m> Specify ALSA params to open output device
b = buffer time in ms or size in bytes,
p = period count or size in bytes,
f = sample format (16|24|24_3|32),
m = use mmap (0|1)
Hi-Res Downloads - Buy studio-quality classical music | Presto Classical
This is common these days. Tidal is full of it.
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This is common these days. Tidal is full of it.
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Great - how did that make you feel
Like I was doing something entirely pointless...
Only if the signal is repetitive and distinct enough.
So let me give you a different angle: How loud is the loudest part of music you listen to? Let's assume you have really efficient speakers, huge amps, and don't care about your hearing, and can play up to 110 dBSPL. Do you think you also can hear something that is quieter than 15 dBSPL? Do you think it was that quiet in the recording studio?