DSP Xover project (part 2)

The damage occurs as a discontinuity in the time domain. This isn't going to show up as noise or distortion (in your measurements) but is noticeable in listening.

There is no discontinuity in the time domain or anything that you can hear. If anything the artifacts are at least 120 dB down or more depending on the SRC which is way below the resolution of 16 bit audio. If you can hear that over quantisation errors in 16 bit recordings then you are most likely imagining it ;)
 
for you information:

OpenDRC Series | miniDSP
http://www.minidsp.com/images/documents/Product Brief-MiniDSP.pdf
Behringer: ULTRA-DRIVE PRO DCX2496
http://www.quickfiltertech.com/html/content_page.php?content_id=65&
http://www.quickfiltertech.com/html/content_page.php?content_id=86&

my interest:
Stereo 3/4/5 way Crossover
44-96 khz sampling rate
I2S several inputs/outputs
types of filters (LP/BP/HP) for each input and output
Adjustable Delays for all inputs and outputs
crossover (6-48 db/octave or higher) + FIR (xxxxx taps mono or stereo)
possibility of linking multiple dsp cards?
winxp compatible?
Graphic & Parametric equalizers ,selectable for all inputs and outputs
 
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my interest:
Stereo 3/4/5 way Crossover
44-96 khz sampling rate
I2S several inputs/outputs
types of filters (LP/BP/HP) for each input and output
Adjustable Delays for all inputs and outputs
crossover (6-48 db/octave or higher) + FIR (xxxxx taps mono or stereo)
possibility of linking multiple dsp cards?
winxp compatible?
Graphic & Parametric equalizers ,selectable for all inputs and outputs

Hi Enantra,

I'll make all the above available except graphic eq.
When it comes to linking boards, what do you have in mind?

Best

Nick
 
In what way does the spdif coaxial digital out's differ from the I2S connection ?

The board has 10 digital outs (5 stereo pairs).
8 of them carry the same signal as the analogue outs. The remaining output can convey an extra pair of signals for who needs 10 outputs.

Additionally, the board has 2 I2S ports. They can be used as inputs or as outputs.

I'm not sure I've fully understood your question. Please let me know if you need more information.
 
To connect more then one dac to the I2S was not without problems as discussed earlier (clocking, cabling etc).
I'm looking at the possibility to connect three external dac's, volumecontrol and tubebased buffers.
I really like the dac I'm using rigth now and it would just take a different position with this solution.
The question, are the two different connection alternatives basically the same or ????

Bye the way, usb reciver ordered :)

An externally hosted image should be here but it was not working when we last tested it.


Have you had the time to consider the u fl connectors ?
 
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To connect more then one dac to the I2S was not without problems as discussed earlier (clocking, cabling etc).
I'm looking at the possibility to connect three external dac's, volumecontrol and tubebased buffers.
I really like the dac I'm using rigth now and it would just take a different position with this solution.
The question, are the two different connection alternatives basically the same or ????

Bye the way, usb reciver ordered :)

http://luckit.biz/new/wp-content/uploads/2012/07/waveIO2.png

Have you had the time to consider the u fl connectors ?

I need to know more about your dacs. Basically, if they take SPDIF inputs, then go for the SPDIF outs on the dsp board. If they take I2S inputs, then you have to use the I2S outs on the board.

There shouldn't be any problem to connect the USB receiver, and you could use 1 I2S port for the USB receiver, and the second I2S port for your 3 dacs.

I don't have any statement regarding u fl so far (I'm full-time into programming right now).
 
Ok, I'm reading up on spdif versus I2S elsewhere so lets drop that for now :)

Basically, SPDIF is plug and play meanwhile I2S is not.

SPDIF (Sony Philips Digital Interface) is a single signal that carries audio data and some metadata, with the clock embedded in the signal using biphase mark coding. This coding strategy allows extracting the clock and the data separately from the stream.

On the other hand, I2S (Inter IC Sound) is a protocol for conveying audio data between chips. I don't think it was ever intended for use by the final user, but only for electronic engineers designing the board. It consists mostly in 3 signals: the data, the bit clock that's useful for sampling the latter data stream, and the Left/Right clock useful for deciding if the bits being sampled belong to the left of the right channel.

On the SPDIF side, all the communication aspects have been normalized: the signal amplitude, the line impedance, and there's theoretically enough metadata in order to properly decode the data stream.

On the other hand for I2S, it's all up to the designer. Voltage levels are not normalized (it can be 3.3V, 5V or whatever, TTL or CMOS). Then the receiver must know how the bits are aligned in the stream, how many clocks per frame (referred to fs clock) etc. This makes that if you plan to transfer audio with I2S, you must know exactly what the transmitter is able to spit out, then setup the receiver accordingly (and sometimes insert logic level translation between the receiver and the transmitter).

Nice to hear that the programming is coming along, are you expecting us to
participate in some way ? Maybe ideas for neat functions ? For instance, I
could go for a variable slope function for the shelving filters instead of the
usual fixed 6 or 12db's. From 3 to 12db maybe.

Yes there's a lot of stuff going on lately. Mostly programming, but I'm also on the way to finish hardware debugging. Now regarding suggestions for more features, I must say I already have a huge list of processing routines that I need to implement and I'm not going to add anything on it before the first release in October - otherwise it's going to push back the initial release. After the first release I'll be more than happy to take good note of every one's needs.
 
Will there be any pre-presentation of hard and software before the actual release ?

I'll do my best to make information available as the various components (hardware, firmwares and software) are getting close enough to their final form for the release.

This week I've set up the digital input and the sample rate converter. It's all going smoothly and the project is on track.

One more feature I haven't mentioned so far: There's also onboard an isolated command for external relays intended for turning on and off your amps.
 
Lets say I'm going for the digital solution, analog + digital + I2s input / spdif out.
Is there still need for the +/-12v supply then ?

Ok. The 5V supply is only used to power digital sections. Some chips use this 5VD as supplied, others require 3.3V and/or 1.2V. The latter are derived from 5VD with onboard regulators.

There's a separate 5VA (analogue). It's derived from the +12V supply. That's why you must always provide +/-12V.

If you plan to use an analogue volume chip, CS3318 needs +/- 8 to 9V and CS3308 needs +/- 5V. These 2 supplies are again derived from +/-12V with onboard regulators.

About the 5v supply. How much current will be sufficient ?
1A is safe. Power lines are also available on the expansion ports so you can draw current here for your devices attached.
 
Hi gents!

I have now approximate pricing information for the DSP board including software. To be confirmed!

- between USD 260 and USD 290 for the board without analogue volume.
- between USD 280 and USD 330 for the board with analogue volume (CS3318).

Shipping comes on top in all cases. For UE buyers, add 15% VAT.

I'll order a production run soon so that I can start delivering in October if there's no major shortage of chips.

I need to have a feel of what proportion of boards should get the analogue volume chip mounted on it, so I'd like to ask you whether you would prefer a board with the CS3318, or without that chip in order to save about USD 40. (If there's no analogue volume chip, the DACs are in charge of the volume control in digital domain - so there's still volume control, no worries).

This is not an order request or whatever, it's just for me to have a feel of how many CS3318 I should buy. So unless you don't need a DSP board at all, don't be shy to give your input. It's a kind of poll - I'm not going to contact anyone who's taking part.

My initial guess is fifty-fifty.