DSP Xover project (part 2)

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#2,341
Relay timer feature

chaparK said:
Najda's remote trigger is well suited for driving external relays. Please check the interface chip datasheet: FOD852S.
Click to expand...

Hi Nick,

Thanks for your clarification on the remote trigger.

I see there is an option to delay the action for the remote trigger so Najda can power up safely before speakers are connected.

I hope to use this function for amplifier control, and was wondering if you would consider implementing a delayed turn off for Najda. So when you switch to stand by, the remote trigger switch is opened immediately (to shut the amps down) but Najda delays turning off until amps are safely shut down. Although I don't get pops or nasty noises when switching to standby I hope to implement off board DACs that may have more of an issue when shutting down, so think this could be a nice safety feature and follows best practice for turning amps on last and off first.

So sequence could go something like:

1. Najda turns on (from stand by) > adjustable relay timer ON > remote trigger switch closes (to turn on amps or engage speakers).

2. Najda switch to standby > remote trigger switch opens (to turn amps or speakers off ) > adjustable relay timer OFF> Najda goes to standby.

The remote trigger could then be used more effectively for either speaker disconnection or amplifier control.

If you or others think there's merit in this, I hope you will consider for implementation in a future firmware version. It's no deal breaker but would be a nice to have.

Many thanks.
 
#2,342
mikebond said:
First result is very impressive! After separate measuring each driver necessary delay was added and also I made some correction for tweeter with Paragraphic Gain EQ in rePhase. The sound is amazing even with not the best amps for high-mids and highs. This FR was measured with the mic placed on the listening point
Click to expand...

Looks pretty good Mike! Glad you like how it sounds :cheers:

mikebond said:
Hi Nick!
Some time ago you promised about possibility to use IIR and FIR in the same setting. Is it still in development?
What about possibility to have more coefficients per channel, if the limit of 3580 coefficient for each DSP core not reached? For example, if I need only 3 channels with FIR filters, can I have 1193 coefficients per channel?
Click to expand...

The mix IIR/FIR is still in the pipeline, along with more features.

Currently, memory allocation for each channel is static - this is what's limiting the number of taps per channel. I could modify that, but that would take some time as it's not a trivial change.

Bud Barnez said:
Hi Nick,

Thanks for your clarification on the remote trigger.

I see there is an option to delay the action for the remote trigger so Najda can power up safely before speakers are connected.

I hope to use this function for amplifier control, and was wondering if you would consider implementing a delayed turn off for Najda. So when you switch to stand by, the remote trigger switch is opened immediately (to shut the amps down) but Najda delays turning off until amps are safely shut down. Although I don't get pops or nasty noises when switching to standby I hope to implement off board DACs that may have more of an issue when shutting down, so think this could be a nice safety feature and follows best practice for turning amps on last and off first.

So sequence could go something like:

1. Najda turns on (from stand by) > adjustable relay timer ON > remote trigger switch closes (to turn on amps or engage speakers).

2. Najda switch to standby > remote trigger switch opens (to turn amps or speakers off ) > adjustable relay timer OFF> Najda goes to standby.

The remote trigger could then be used more effectively for either speaker disconnection or amplifier control.

If you or others think there's merit in this, I hope you will consider for implementation in a future firmware version. It's no deal breaker but would be a nice to have.

Many thanks.
Click to expand...

Yes a 'OFF-delay' could be added to the relay command, not a big issue.
 
#2,343
chaparK said:
Looks pretty good Mike! Glad you like how it sounds :cheers:



The mix IIR/FIR is still in the pipeline, along with more features.

Currently, memory allocation for each channel is static - this is what's limiting the number of taps per channel. I could modify that, but that would take some time as it's not a trivial change.



Yes a 'OFF-delay' could be added to the relay command, not a big issue.
Click to expand...

Isn't the other limitation the number of taps that can be processed per sample interval ?
 
#2,344
Any advise on fitting an Amanero I2S card to my Nadja please. What outputs do i need to connect? The only advise to date i have got is not to connect the DSP ON. Do i need an isolator chip, what advantages/disadvantages does it bring.
BTW- I have a dedicated spare 3.3V low noise supply (1A) which i was going to feed it with.
 
#2,346
vinylnvalves said:
Any advise on fitting an Amanero I2S card to my Nadja please. What outputs do i need to connect? The only advise to date i have got is not to connect the DSP ON. Do i need an isolator chip, what advantages/disadvantages does it bring.
BTW- I have a dedicated spare 3.3V low noise supply (1A) which i was going to feed it with.
Click to expand...

Hi,
My Amanero is Connected like attachment. Also remember to Connect pin 13 and if you have shilded cable, you should also use pin 22,24 and 26 on Najda.

Best,
Paal
 

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#2,347
Well, I think my Nadja is pretty much complete now. I may add a balanced analog input but otherwise it's working quite well and putting out a respectable noise.

The only thing I really, really want from my Nadja is access to another 2ch of I2S output! Please Nick, if there's some way for me to get more I2S output can you let me know? I don't mind if it involves a little surface-mount soldering (although prefer not 🙂 )

Here's a pic - I believe there's at least 30m of cable in that box so the fact that it looks kinda tidy is an achievement in itself.
 

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#2,348
Just a quick note to say that based on recommendations (some from here) I ordered a WaveIO USB->IS2 for my computer based music serving.

Once installed it sounds very good indeed!

Great service/support and also special thanks to JLOP for his excellent pin to pin description of how to wire the two up.

All that remains is to add some more LEDs to show the less common sample rates and pretty up the installation.
 
#2,349
Had unpleasant issues with WaveIO. I had to disconnect it from may setup after a few weeks.

It was a high frequent noise while placing the WaveIO to close to Najda, it was gone when i placed WaveIO 2cm away from Najda. The second issue was a different but also high frequent noise in the loudspeakers when Wave IO was connected to USB. Solved by unplugging the WaveIO. Waveio was powered by a separate PSU, the isolator 5v from Najda board... Now i´m using the optical SPDIF attached to a MacMini.

apoo
 
#2,350
apoo said:
Had unpleasant issues with WaveIO. I had to disconnect it from may setup after a few weeks.

It was a high frequent noise while placing the WaveIO to close to Najda, it was gone when i placed WaveIO 2cm away from Najda. The second issue was a different but also high frequent noise in the loudspeakers when Wave IO was connected to USB. Solved by unplugging the WaveIO. Waveio was powered by a separate PSU, the isolator 5v from Najda board... Now i´m using the optical SPDIF attached to a MacMini.

apoo
Click to expand...
I also had noise problems when I initially attached a WaveIO board to the I2S on the Najda board.

This was solved by doing three things, first I used an external power source (5 volt battery), secondly I created a powerless USB cable (I.e. Only D+,D- and screen). These two steps removed most of the noise, I still some very low level noise but since my speakers have a 104db sensitivity it was still audible.

Lastly I changed from the non-isolated I2S connectors to the isolated powering from the Najda I2S pins.

The WaveIO is a few mm from the Najda and there is absolutely no noise.

I previously used an exau2i board and this produced no noise either when located next to the Najda.

Can I suggest you persevere with the WaveIO, it is good.
 
#2,353
The exau2i only has isolated outputs and it was quiet, the WaveIO on the isolated was fine. I seem to recall someone mentioning that it was recommended to not use the earths if using the non-isolated outputs, I will try to find the post.

A lot of noise is ground related and system dependant.
 
#2,354
Had unpleasant issues with WaveIO. I had to disconnect it from may setup after a few weeks.
Click to expand...

I've juste installed my WaveIO card and after few hours of listening differents songs/tracks : 16 bits/44.1 khz, 24 bits/96 khz and even 24 bits/192 khz. Evrything is working fine 🙂 I'm not experiencing any type of clics or noise.

WaveIO card is powered by USB and connected to the Najda via the isolated I2S output. The card will be powered by the Najda PSU in the future.
 
#2,358
Alright, I assume your preset rate is 96 kHz.

Then the signal path is CD SPDIF (44.1 kHz) -> ASRC -> DSP (96 kHz) -> SPDIF OUT (96 kHz).

You need to check your documentation and see if your DAC supports 96 kHz FS. If not, then create a 48 kHz setup for this use.
 
#2,360
Thanks Nick! That fixed it🙂 Old dac!

Next question is can I disable the analogue outputs in a way that they are always default muted / not active?

I don't want to accidentally flick to my 48KHz Headphone setting when the main amps are on and send passthrough to my drivers...
I can't add X/O's as it cuts the signal to the headphones or am I missing a pure SPDIF unchanged output somewhere?


chaparK said:
Alright, I assume your preset rate is 96 kHz.

Then the signal path is CD SPDIF (44.1 kHz) -> ASRC -> DSP (96 kHz) -> SPDIF OUT (96 kHz).

You need to check your documentation and see if your DAC supports 96 kHz FS. If not, then create a 48 kHz setup for this use.
Click to expand...
 
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