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Old 11th April 2013, 08:32 PM   #881
SAC is offline SAC  United Kingdom
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Thanks Nick,

I fear the HDMI option is not workable. I2S is a signal it sounds like, whereas I thought it was describing just the hardware, and therefore the following link may be applicable here;
DAC-2 I2S Input - Frequently Asked Questions - WYRED 4 SOUND
"The DAC-2 I2S input is specifically for a balanced IS signal and will not work with standard HDMI outputs that you will find on electronics such as some TVs, Audio Video Receivers, DVD players, etc."

Nonetheless, I am still interested in this board. Was thinking two Minidsp 2X4 for my four-way active speakers, but the Najda seems better quality, a preamp thrown in, and ultimately costing similar money for a lot more.

However, would like to build the Nao Note II so was a bit disappointed the Najda did not tick all of John Krekovskys' boxes;
"However, the limitations on gain of 12dB for EQ sections makes it impossible to get the exact transfer function for the woofer.
Additionally, the PEQ Q values can only be set to 1 decimal point while 2 are required for accuracy.
Lastly, since the PEQ Q definition is different that the analog version (like miniDSP) it's a trial and error setup. For miniDSP I have software that generates the biquad coefficients based on the analog Q which is how I design."
NaO Note II RS
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Old 11th April 2013, 11:36 PM   #882
zoula is offline zoula  Canada
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Location: Montreal
Hi Nick,

I'm also on the verge to update my system and I will be also building the Note II RS. I would also like to go with your DSP board since it seems more powerful and it offer me more flexibility then the MiniDSP board for how I will be hooking my system (dac preamp multiple source etc...)

But I really need what JohnK needs to use your board. witch are
1. limitations on gain of 12dB for EQ sections
2. PEQ Q values can only be set to 1 decimal point while 2 are required for accuracy
3. possibility to generate your own Biquad filter which is how I intend to program my DSP....

I'm sure those request could be implemented easily. JohnK is a well respected loudspeaker designer and your board will sure be sold more if you can manage a fix for this....

Thank you
J-P
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Old 12th April 2013, 12:38 AM   #883
chaparK is offline chaparK  Luxembourg
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Quote:
Originally Posted by SAC View Post
Thanks Nick,
Nonetheless, I am still interested in this board. Was thinking two Minidsp 2X4 for my four-way active speakers, but the Najda seems better quality, a preamp thrown in, and ultimately costing similar money for a lot more.

However, would like to build the Nao Note II so was a bit disappointed the Najda did not tick all of John Krekovskys' boxes;
"However, the limitations on gain of 12dB for EQ sections makes it impossible to get the exact transfer function for the woofer.
Additionally, the PEQ Q values can only be set to 1 decimal point while 2 are required for accuracy.
Lastly, since the PEQ Q definition is different that the analog version (like miniDSP) it's a trial and error setup. For miniDSP I have software that generates the biquad coefficients based on the analog Q which is how I design."
NaO Note II RS
Quote:
Originally Posted by zoula View Post
Hi Nick,

I'm also on the verge to update my system and I will be also building the Note II RS. I would also like to go with your DSP board since it seems more powerful and it offer me more flexibility then the MiniDSP board for how I will be hooking my system (dac preamp multiple source etc...)

But I really need what JohnK needs to use your board. witch are
1. limitations on gain of 12dB for EQ sections
2. PEQ Q values can only be set to 1 decimal point while 2 are required for accuracy
3. possibility to generate your own Biquad filter which is how I intend to program my DSP....

I'm sure those request could be implemented easily. JohnK is a well respected loudspeaker designer and your board will sure be sold more if you can manage a fix for this....

Thank you
J-P
Alright, this is interesting feedback and I'm quite happy that there's a forum to discuss about these matters.

Regarding gain on EQ, I can actually set it to any number straight away. It's just a constant in the software and I've set it initially to 12 dB because it seemed safe for less experimented users. Just tell me how much gain you need and I'll make this available, no problem.

Regarding Q factor with 2 decimal points, no problem neither. I put it in the pipeline.

Finally, and I think this is your last point, custom biquads is already being looked at, that's part of the next release, coming soon (with FIR/IIR mix).

Thanks for reporting your concerns, that's how I can make Najda better.

Best,

Nick
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Old 12th April 2013, 01:48 AM   #884
SAC is offline SAC  United Kingdom
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Sounds good Nick, looking forward to the revisions. I do not know the eq settings so hopefully someone else can contribute or I'll ask JohnK.
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Old 12th April 2013, 07:21 AM   #885
jcga is offline jcga  France
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Quote:
Originally Posted by chaparK View Post
Finally, and I think this is your last point, custom biquads is already being looked at, that's part of the next release, coming soon (with FIR/IIR mix).
Nick
Nice, the FIR/IIR mix will let me experiment FIR global phase correction !

About the 12 dB max, in fact you have a 24 dB range already (+/- 12 dB) but I understand that in some rare case you need more than that.

Jean Claude
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Old 12th April 2013, 01:19 PM   #886
SAC is offline SAC  United Kingdom
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Quote:
Originally Posted by chaparK View Post
Just tell me how much gain you need and I'll make this available, no problem.
JohnK had this to say;
"that depends of the design of the woofer system. For example, depending on which woofer is used and what the cut off frequency is, in one of my dipole woofer systems I need A Q PEQ boost of anywhere between 11 and 22dB. "
NaO Note II RS
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Old 12th April 2013, 01:30 PM   #887
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Well,

I have all the parts on order now except the case but I will wait with that until I have everything tested out. It's fibreboard until then.

I ended up ordering this display:
OLED Display

I'm waiting for the WaveIO board from Lucian as well which I will integrate via the I2S input so that's another datapoint for the I2S once I get it configured.

I have looked at this page:
OP amps

I'm tempted to just order some NJM4562's and be done with it since they are measured to actually perform better than the LM833.

Nick, would that be a drop in replacement?

Great to hear about the custom biquads since that's another requirement from my side.
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Old 12th April 2013, 01:55 PM   #888
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Specifically this one: LM4562

Comments?
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Old 12th April 2013, 02:07 PM   #889
palmito is offline palmito  United States
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Default Nao Note builder too!

I too started following this thread because I'm building a Nao Note and thought this would be perfect for it. I will definitely purchase one if it can be used for the Nao. Thanks.
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Old 12th April 2013, 05:23 PM   #890
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This thread might be of interest:

Python Open Room Correction (PORC)
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