Minidsp sampling frequency.

oon_the_kid · 15th February 2011, 05:54 PM

Hi,

I am interested in purchasing a minidsp plus miniamp set up. I would like to know one thing first. It seems the sampling frequency of the minidsp is 48KHz. So what happens when I input in a spdif from a cd player. Does it convert the 16 bit 44.1KHz signal to a 28 bit/48KHz signal first before it starts messing around with the signal?

Oon

oon_the_kid · 15th February 2011, 11:57 PM

Hi,

A few more questions.

1) If I use the USB streamer board for a minidsp+amp, I don't need the minidigi board anymore right? It can receive input from USB and SPDIF, correct?

2) Most of my material will be from a CD player. Can the Minidsp run at the native frequency or at a higher sampling rate 96KHz. From a hifi perspective that is less inaccuracy to the signal.

3) The Miniamp has a PWM out for subwoofer. Do you have an application circuit on how to utilise the PWM switching signal out? External transistors perhaps?

Thank you.

Oon

minidsp · 16th February 2011, 09:14 AM

Oon,

In answer to your questions,
- the miniDIGI indeed will convert any digital input signal it receives (up to 192kHz) to 48kHz thanks to the Asynchronous Sample Rate Converter (ASRC) that is provided on the input. No need to worry about bits. :-)
- Note that the miniStreamer isn't meant to really integrate to the miniDSP + miniDIGI. While a ministreamer + miniAMP will work easily, a ministreamer to MiniDSP configuration isn't as plug&play and not recommended without a miniDIGI (taking care of the ASRC).
- The miniDSP only runs at 48kHz I'm afraid.
- We don't have any app note on how to use the PWM output. You would need an output power stage to get that PWM output to power anything. Not some resistors.. We actually never got that request to implement the PWM out... we could look into it later on next week.

Hoping this info helps,

DevTeam

oon_the_kid · 16th February 2011, 10:26 AM

thanks for the prompt reply. I have some slight concerns on the resampling. If the resampling is done at a much higher frequency, I would be more comfortable. I suppose the system has some form of interpolation when it is resampling to guess the values in between the dots. Bypassing the dsp is also disturbing, since I have no way of implementing volume control.

Having an external board with the suitable transistors, similar to that from a tripath ta 3020 would be nice too. Then I can easily use it in biamping arrangement with the stereo pwm subwoofer out for bass.

Oon

Oon

Having a

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lduarte1973 · 7th April 2011, 05:11 PM

will mini dsp ever have a 192khz sampling rate ? i was thinking of using it as a digital crossover with my cambridge audio 740c cd player , spdif is 192khz.

minidsp · 11th April 2011, 10:52 AM

Quote:

Originally Posted by lduarte1973

will mini dsp ever have a 192khz sampling rate ? i was thinking of using it as a digital crossover with my cambridge audio 740c cd player , spdif is 192khz.

We could indeed get it to operate to 192kHz with a new plug-in on the miniDSP 2x8. Whether it will happen or not is a bit early to say...

Only the 2x8 platform currently has enough power to process data @ 192kHz though. And if we ever decide to do it, we would only be left with a 2x4 configuration (1/2 of the current 96kHz)... Anyway, we just released this platform, so gotta give it some time. :-)

lduarte1973 · 11th April 2011, 05:51 PM

i cant use it as a 3 or 4 way crossover then ?

oon_the_kid · 12th April 2011, 01:54 PM

Hi,

I purchased the minidigi/minidsp/miniamp combo recently. I am quite happy with the sound so far.

however, I feel if 96KHz can be implemented at a sacrfice of some funtionality via a plug in, you should create such a plug in. I have the 2.1 plug in and I feel some of the functionality is overkill, peq before and after crossover... for example. One is sufficient.

by not putting it in , you are alienating a lot of hifi buff. It would be the same reason. Would you buy 48KHz dac? You would buy an nos sampling dac (44.1 KHz) because it is the original data. You buy a 96KHz dac because it is upsampled. But if you buy a 48KHz dac, you would have lost original data due to resampling but it is not a significant higher sample rate.

Oon

lduarte1973 · 12th April 2011, 02:51 PM

Hi , that´s my problem , my Cambridge audio 740c upsamples to 24/384khz , i wouldn´t mind going down to 192 but not to 44.1

oon_the_kid · 12th April 2011, 03:38 PM

Hi Iduarte,

Just not to add any confusion, The earlier message was meant for minidsp. Like you, I am not happy with the 48KHz sample rate. I feel the data is getting corrupted. Unfortunately the minidsp 2 X 8 is US$300...

Oon

15th February 2011, 05:54 PM	#1
oon_the_kid diyAudio Member Join Date: May 2008	Minidsp sampling frequency. Hi, I am interested in purchasing a minidsp plus miniamp set up. I would like to know one thing first. It seems the sampling frequency of the minidsp is 48KHz. So what happens when I input in a spdif from a cd player. Does it convert the 16 bit 44.1KHz signal to a 28 bit/48KHz signal first before it starts messing around with the signal? Oon

16th February 2011, 09:14 AM	#3
minidsp diyAudio Member Join Date: Dec 2009	Oon, In answer to your questions, - the miniDIGI indeed will convert any digital input signal it receives (up to 192kHz) to 48kHz thanks to the Asynchronous Sample Rate Converter (ASRC) that is provided on the input. No need to worry about bits. :-) - Note that the miniStreamer isn't meant to really integrate to the miniDSP + miniDIGI. While a ministreamer + miniAMP will work easily, a ministreamer to MiniDSP configuration isn't as plug&play and not recommended without a miniDIGI (taking care of the ASRC). - The miniDSP only runs at 48kHz I'm afraid. - We don't have any app note on how to use the PWM output. You would need an output power stage to get that PWM output to power anything. Not some resistors.. We actually never got that request to implement the PWM out... we could look into it later on next week. Hoping this info helps, DevTeam __________________ www.minidsp.com - Low cost & modular audio DSP kits for DIYers - Follow our tweets @ minidsp

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15th February 2011, 11:57 PM	#2
oon_the_kid diyAudio Member Join Date: May 2008	Hi, A few more questions. 1) If I use the USB streamer board for a minidsp+amp, I don't need the minidigi board anymore right? It can receive input from USB and SPDIF, correct? 2) Most of my material will be from a CD player. Can the Minidsp run at the native frequency or at a higher sampling rate 96KHz. From a hifi perspective that is less inaccuracy to the signal. 3) The Miniamp has a PWM out for subwoofer. Do you have an application circuit on how to utilise the PWM switching signal out? External transistors perhaps? Thank you. Oon

16th February 2011, 10:26 AM	#4
oon_the_kid diyAudio Member Join Date: May 2008	thanks for the prompt reply. I have some slight concerns on the resampling. If the resampling is done at a much higher frequency, I would be more comfortable. I suppose the system has some form of interpolation when it is resampling to guess the values in between the dots. Bypassing the dsp is also disturbing, since I have no way of implementing volume control. Having an external board with the suitable transistors, similar to that from a tripath ta 3020 would be nice too. Then I can easily use it in biamping arrangement with the stereo pwm subwoofer out for bass. Oon Oon Having a Sent from my Milestone using Tapatalk

7th April 2011, 05:11 PM	#5
lduarte1973 diyAudio Member Join Date: Feb 2009 Location: Lisbon	will mini dsp ever have a 192khz sampling rate ? i was thinking of using it as a digital crossover with my cambridge audio 740c cd player , spdif is 192khz.

11th April 2011, 05:51 PM	#7
lduarte1973 diyAudio Member Join Date: Feb 2009 Location: Lisbon	i cant use it as a 3 or 4 way crossover then ?

12th April 2011, 01:54 PM	#8
oon_the_kid diyAudio Member Join Date: May 2008	Hi, I purchased the minidigi/minidsp/miniamp combo recently. I am quite happy with the sound so far. however, I feel if 96KHz can be implemented at a sacrfice of some funtionality via a plug in, you should create such a plug in. I have the 2.1 plug in and I feel some of the functionality is overkill, peq before and after crossover... for example. One is sufficient. by not putting it in , you are alienating a lot of hifi buff. It would be the same reason. Would you buy 48KHz dac? You would buy an nos sampling dac (44.1 KHz) because it is the original data. You buy a 96KHz dac because it is upsampled. But if you buy a 48KHz dac, you would have lost original data due to resampling but it is not a significant higher sample rate. Oon

12th April 2011, 02:51 PM	#9
lduarte1973 diyAudio Member Join Date: Feb 2009 Location: Lisbon	Hi , that´s my problem , my Cambridge audio 740c upsamples to 24/384khz , i wouldn´t mind going down to 192 but not to 44.1

12th April 2011, 03:38 PM	#10
oon_the_kid diyAudio Member Join Date: May 2008	Hi Iduarte, Just not to add any confusion, The earlier message was meant for minidsp. Like you, I am not happy with the 48KHz sample rate. I feel the data is getting corrupted. Unfortunately the minidsp 2 X 8 is US$300... Oon