DSP Xover project (part 2) - Page 91 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th April 2013, 10:25 AM   #901
diyAudio Member
 
Speedysteve7's Avatar
 
Join Date: Dec 2009
Location: Hants/Berkshire/Surrey
Quote:
Originally Posted by kazam View Post
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.
That OLED looks cool... Op amps - ah the fun we have in store for us.
  Reply With Quote
Old 13th April 2013, 10:32 AM   #902
diyAudio Member
 
Speedysteve7's Avatar
 
Join Date: Dec 2009
Location: Hants/Berkshire/Surrey
My case arrived from HK today.

I got them to pre-drill the holes for LEDs and push to make switches.
I have to cut out the LCD or Oled slot. I think a gold plated surround plate would look nice and bling and match my MF A3 CDP that I use as a transport...

All parts. Very nice construction and solid 8mm ali face plate...

Click the image to open in full size.

Pre-drilled and switches sitting in
Click the image to open in full size.

I have to drill the rear panel too. Gonna be working on this a bit this weekend.
  Reply With Quote
Old 13th April 2013, 10:34 AM   #903
chaparK is offline chaparK  Luxembourg
diyAudio Member
 
Join Date: Apr 2010
Location: Luxembourg
Quote:
Originally Posted by jcga View Post
Nice, the FIR/IIR mix will let me experiment FIR global phase correction !
Release expected beginning of May

Quote:
Originally Posted by SAC View Post
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
Alright, I'll make 24 dB of gain available. And also up to -24 dB of attenuation in front of the filtering blocks so that you don't clip.
It seems a bit dangerous for less experimented users, who could be tempted to cascade a lot of gain locally - but on the other hand I don't want to limit others.

Quote:
Originally Posted by kazam View Post
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.


Quote:
I ended up ordering this display:
OLED Display
That's interesting.
Note that there's no backlighting. So no connection and the backlight option in the menu is not applicable anymore.
There's also no contrast setting, you won't need that. Again, no connection and contrast menu option irrelevant.
Please let us know how it goes!

Quote:
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.
That's another interesting configuration. Looking forward to your feedback. So far we've tested Tenor and Amareno.

Quote:
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?
I looked at the datasheet and it should be fine. Mind you: LM833 is not bad at all. I'd actually suggest that you first get used to the sound of the board with the supplied opamps, and only later try to upgrade because the change is going to be a rather subtle one I think (Hope you'll let us know).

I had tested a few opamps. I'll find the list again and I'll post it here.

Quote:
Great to hear about the custom biquads since that's another requirement from my side.
Early May

Quote:
Originally Posted by palmito View Post
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.
No problem, changes are in the pipeline. Thanks for your interest.

Quote:
Originally Posted by Davey View Post
They're talking about EQ corrections not level adjustments.

The shelving filters are limited (currently) to +/-12db gain, but you can cascade (add) sections to achieve dipole corrections (or whatever else) of greater than 12db.
If Nick were to change the software to allow >12db settings for the filters it won't improve the situation with regard to gain structure.....but it will make it a bit more straightforward to program......at least with the "free routing" scheme.

Cheers,

Dave.
Thanks Dave. I'll make that change. To me, the idea of actually cascading biquads is also a bit pitiful because that's wasting DSP resources.

Quote:
Originally Posted by rubofdagreen View Post
I decided to do a little beautification project on the interior today. After wrestling the wires into neat packages the LCD was displaying weirdly. I checked the connections and gave them all a little love squeeze. All is back to normal. Nick, On the next board please make the numbers for the LCD linear. 1 thru 8 in a row and 9 thru 16 in the other. The LCD's I bought are all in a line and it's hard to assemble all those little connectors.
Love squeezes is all we need
Thanks for your feedback, and truth is that I had thought about it at some time.
The problem is that there's no standard for LCD pin out. Some display modules have the pins on 2 rows, just like Najda, and allow the use of a 1-to-1 cable. I think Shaun has such a display (Can you confirm Shaun?).

Quote:
Originally Posted by paalj View Post
Hi Nick,
Thanks for all your hard work!
I have a question.
Are the outputs directly connected to the cs3318 or is the signal passing any of the opamps after leaving the analog volume control?

best,
Paal
Hi Paal,

CS3318 is the last stage before the output connectors.

Best,

Nick
__________________
Najda DSP
  Reply With Quote
Old 13th April 2013, 10:40 AM   #904
chaparK is offline chaparK  Luxembourg
diyAudio Member
 
Join Date: Apr 2010
Location: Luxembourg
Quote:
Originally Posted by Speedysteve7 View Post
My case arrived from HK today.

I got them to pre-drill the holes for LEDs and push to make switches.
I have to cut out the LCD or Oled slot. I think a gold plated surround plate would look nice and bling and match my MF A3 CDP that I use as a transport...

All parts. Very nice construction and solid 8mm ali face plate...

Click the image to open in full size.

Pre-drilled and switches sitting in
Click the image to open in full size.

I have to drill the rear panel too. Gonna be working on this a bit this weekend.
That looks great Steve! Really looking forward to the end result.

The 2 extra analogue outs will come on the Expansion Port 0 side of the board. Please reserve 5 cm on that side in your chassis if you want to fit the expansion board at same height level than the main board.
__________________
Najda DSP
  Reply With Quote
Old 13th April 2013, 11:43 AM   #905
alugner is offline alugner  Sweden
diyAudio Member
 
Join Date: Oct 2010
Location: Ystad
About the +/-12db filter gain. Is such high differences in gain not better addressed by other drivers or power amplifiers? There must be a considerable risk of clipping on the power amplifiers if You need a >24db correction. I might have misunderstood the discussion.
  Reply With Quote
Old 13th April 2013, 12:21 PM   #906
Shaun is offline Shaun  South Africa
diyAudio Member
 
Shaun's Avatar
 
Join Date: Aug 2001
Location: Cape Town, South Africa
I can't wait to hear results of the OLED display. I recall reading on the Adafruit web site that they had to implement a software mod to make it compatible. It would be great to know that no such tweaks are required for this implementation.

Quote:
Originally Posted by chaparK View Post
The problem is that there's no standard for LCD pin out. Some display modules have the pins on 2 rows, just like Najda, and allow the use of a 1-to-1 cable. I think Shaun has such a display (Can you confirm Shaun?).
Right. I posted about it here: DSP Xover project (part 2).

That pin configuration does appear to be a standard of sorts; there are many (older?) displays that use that layout. It seems that most modern displays have serial interfaces. When I was searching for a brighter display, I looked for plasma (FLV) displays. They were quite rare and expensive. There were more 20x2 character displays than 16x2 types. I did come across one particular OLED display that seemed to be made as a plug-in replacement for the type I used, but none were immediately available at the time. OLED displays having the equivalent display area are typically smaller in overall size, so those may have been a special build.

I think if builders' search for suitable displays do uncover a current trend towards a common pin layout, it would be wise to report that here. We may be able to find a connectivity solution that benefits us all.
__________________
Shaun Onverwacht
|||||||||| DON'T PANIC ||||||||||
  Reply With Quote
Old 13th April 2013, 12:22 PM   #907
jcga is offline jcga  France
diyAudio Member
 
Join Date: Jun 2004
Location: Paris
Quote:
Originally Posted by paalj View Post
Hi,
I have not had any good sucess with room correction. I guess my knowledge is the limit
Paal
I don't want to start a polemical thread here but I still don't understand how you can correctly make Room correction above let's say to simplify 100 Hz or so... without changing massively the direct/reverberant ratio.

But I use a sharp IIR notch to remove the first main room mode successfully (27,8 Hz).

Quote:
Originally Posted by paalj View Post
Anyway, Acourate should be exellent for making filters when Nick now introduces a FIR option.
Paal
Not sure I understand here, Najda already let you use FIR but of course with a reduced number of taps. This reduced number is the main reason why I suggested to Nick to introduce a mix FIR/IIR environment as you can use computer efficient IIR to bring a system close to an overall minimum phase device and apply global pre-phase correction with FIR.

Nick,
The upcoming software/firmware release with mix FIR/IIR and advanced biquad programming is a very good news !

Jean Claude
  Reply With Quote
Old 13th April 2013, 01:11 PM   #908
paalj is offline paalj  Norway
diyAudio Member
 
Join Date: Nov 2005
Location: Norway
Quote:
Originally Posted by jcga View Post
I don't want to start a polemical thread here but I still don't understand how you can correctly make Room correction above let's say to simplify 100 Hz or so... without changing massively the direct/reverberant ratio.

But I use a sharp IIR notch to remove the first main room mode successfully (27,8 Hz).



Not sure I understand here, Najda already let you use FIR but of course with a reduced number of taps. This reduced number is the main reason why I suggested to Nick to introduce a mix FIR/IIR environment as you can use computer efficient IIR to bring a system close to an overall minimum phase device and apply global pre-phase correction with FIR.

Nick,
The upcoming software/firmware release with mix FIR/IIR and advanced biquad programming is a very good news !

Jean Claude
You are probably right regarding room correction.

Regarding FIR, sorry I meant the combined FIR/IIR. Yes I know FIR is already available.

best,
Paal
  Reply With Quote
Old 13th April 2013, 02:34 PM   #909
Davey is offline Davey  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Bremerton, WA.
Quote:
Originally Posted by Julf View Post
Indeed. The lack of balanced output is the main reason I haven't gone for the Najda yet.
You could create one pretty easily.
Measure (or have Nick supply) the output resistance for the unbalanced connectors and an appropriate resistor could be wired from ground to the (-) output on an XLR (or other) balanced connector.
If the capacitance of the load and interconnect cables are within reason that should work well.

The lack of a balanced interface on the Najda board is actually a good thing since it simplifies the architecture and reduces cost.

Cheers,

Dave.
  Reply With Quote
Old 13th April 2013, 02:52 PM   #910
Julf is offline Julf  Europe
diyAudio Member
 
Join Date: Oct 2011
Location: Amsterdam, The Netherlands
Quote:
Originally Posted by Davey View Post
You could create one pretty easily.
Measure (or have Nick supply) the output resistance for the unbalanced connectors and an appropriate resistor could be wired from ground to the (-) output on an XLR (or other) balanced connector.
If it was that easy, I am sure Nick would have added that extra resistor as an option

Quote:
If the capacitance of the load and interconnect cables are within reason that should work well.
I guess it is especially when those conditions don't apply that a proper differential output driver would be beneficial.

Quote:
The lack of a balanced interface on the Najda board is actually a good thing since it simplifies the architecture and reduces cost.
Sure, but there are a lot of other things that could be done if simplicity and low cost were the main drivers.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
DSP Xover project chaparK Digital Line Level 141 3rd July 2011 10:16 AM
Help Please for simple active Xover project dcathro Analog Line Level 4 9th September 2010 05:47 AM
Violet DSP Evolution - an Open Baffle Project cuibono Multi-Way 211 18th May 2010 02:26 AM
Software digital DSP ... Xover/filters/EQ ?? JinMTVT Digital Source 2 8th October 2004 06:02 AM
DSP card & proper xover for heathkit 859A speaker cabinet x. onasis Multi-Way 6 22nd April 2003 07:39 PM


New To Site? Need Help?

All times are GMT. The time now is 07:21 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2