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Old 22nd August 2012, 02:22 PM   #1
WDYSUN is offline WDYSUN  Italy
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Default minDSP 4x10Hd questions

Dear Members,

My eyes stopped on the minDSP 4x10Hd (in a case). I am considering the option to get a miniDSP device in the chain form my new project. However I have several doubts. With this first message I'll try to ask basic things then if responses are positive to me I'll keep asking something more.

I went to a lot of post and I figured out that most problems are with gain-chain (I read the diyaudio article)... as I suspected. Forgive some of my ignorance, and please forgive me if I've overlooked some information already posted. I am not an electronic engineer... please help me understading.

My chain ideal chain is as follows:

Analog playing: Phono → Phono Preamp with volume control → miniDSP analog input → amps and speakers

OR

Digital Playing: PC → usb soundcard SPDIF output → miniDSP digital input → amps and speakers

The amps are solid state (simple designs) with 1V input sensitivity and 33KOhm input impedance, rated at 120W/4Ohms, about 120dB of SNR

The speakers is a 3 ways design with about 95dB 1W/1m

Question 1: Does the miniDSP device allows to switch between analog/digital inputs? This is important because I usually listen 50% vinyls and 50% digital sources.

Question 2: how the miniDSP handles digital operations? Are them integer or floating point?

Question 3: how the miniDSP handles volume control? Did I understood well that a rotary knob can be added to control the output master volume digitally?

Question 4: which kind of ADC and DAC chip are used? Are them integrated into the DSP chip or rather are stand alone chips, if yes which?

Question 5: what about clock? I understood that the chip will resample to 24bit/96KHz, before DSP operatins. Is this clocked to a local quartz or what?


Sorry for the number of questions. I hope somebody ccan explain.

Best Wsihes
Pierre
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Old 22nd August 2012, 03:16 PM   #2
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1 - yes by remote control or connected to pc/laptop , you can have the analog in and digital in always on if you like
3- the 4x10 in a box has already rotary knob that works with remote control too.

the others sorry but i dont know
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Last edited by lduarte1973; 22nd August 2012 at 03:18 PM.
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Old 23rd August 2012, 07:16 AM   #3
WDYSUN is offline WDYSUN  Italy
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Quote:
Originally Posted by lduarte1973 View Post
3- the 4x10 in a box has already rotary knob that works with remote control too.

OK thank you. However I wonder how the volume is handled.

Pierre
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Old 23rd August 2012, 07:41 AM   #4
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Some more answers:

2: DSP is ADAU1445 Sigma DSP from Analog devices. As far as I know it is working internally with 28bit (math is done with 56bit double precision) integer, which is quite common for such DSPs. Precision is sufficient not to introduce errors within the normal operation (e.g. good gain settings, filters as used in the miniDSP plugin software). Have a look to the datasheet for more information.

3. rotary knob and infrared remote control can be used to set the master output volume. The attenuation is done digitally in the DSP or DAC (not absolutely sure where is it done, but should be quite equal wrt quality). I've done some measurements and within a range of -60dB and 0dB THD and S/N does not suffer significantly. If you need more attenuation you should rethink your gain settings (e.g. resistive attenuation after miniDSP) ;-)

4. ADC/DAC is Cirrus Logic CS42528, which is quite good. Have a look to the datasheet for more information.

5: correct. ADC and DSP are running with 24bit/96kHz internaly. If the digital input signal has another sample rate, it will be resampled using the BB SRC4382 asynchronous sample rate converter, which works quite transparent. There is a local master clock onboard.

In gerneral the overall sound quality of the miniDSP 4x10 is really good, especially with view on the given price. There have been several comparisons with other (also much more expensive) DSP systems and the results are very good. I am very happy with my miniDSP2x8

regards, Daniel
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Old 23rd August 2012, 07:48 AM   #5
WDYSUN is offline WDYSUN  Italy
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Hi Daniel,

thanks a lot.

Quote:
Originally Posted by curryman View Post
... rotary knob and infrared remote control can be used to set the master output volume. The attenuation is done digitally in the DSP or DAC (not absolutely sure where is it done, but should be quite equal wrt quality). I've done some measurements and within a range of -60dB and 0dB THD and S/N does not suffer significantly. If you need more attenuation you should rethink your gain settings (e.g. resistive attenuation after miniDSP) ;-)

do you have the balanced or unbalanced version? Which kind of chain do you have? Do you feed it at digital input? What kind of amps/speakers do you have?

Best
Pierre
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Old 23rd August 2012, 07:54 AM   #6
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Pierre if you want to see what i have check my tread :

My setup with minidsp
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Old 23rd August 2012, 10:30 AM   #7
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4x10 has both, balanced and unbalanced outputs

I am using the unbalanced outputs.
Current setup: all sources (CD, DVD, TV) are digital (will add an analog source with DIY MM pre soon), amplifiers are Naim Audio NAP160 + SymAsym and speakers are DIY 2 way (Audax AM170Z2 with B&G Neo3) + Subwoofer (Visaton TIW250 + plate amp).

Best regards, Daniel
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Old 23rd August 2012, 12:59 PM   #8
WDYSUN is offline WDYSUN  Italy
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Quote:
Originally Posted by curryman View Post
4x10 has both, balanced and unbalanced outputs

I am using the unbalanced outputs.
Current setup: all sources (CD, DVD, TV) are digital (will add an analog source with DIY MM pre soon), amplifiers are Naim Audio NAP160 + SymAsym and speakers are DIY 2 way (Audax AM170Z2 with B&G Neo3) + Subwoofer (Visaton TIW250 + plate amp).

Best regards, Daniel
what kind of SPL max you get inroom?

Pierre
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Old 23rd August 2012, 01:52 PM   #9
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3% or 10% THD? ... Didn't measure, so I don't know It is not the perfect setup to blow your ears with heavy metal, however subjectively for me it's OK

I listen to music mostly in the evening when the kids are sleeping and thus I don't need high SPL
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Old 29th October 2012, 08:19 AM   #10
Omholt is offline Omholt  Norway
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Does anyone know if the miniDC isolator can be used with miniDSP 4x10 Hd?
miniDC Isolator | miniDSP
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