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Topic: Paid gig.. (hi/lo pass filters for audio) (fine tuning quality help) (Read 1 time) previous topic - next topic

xl97

Title says it all..

I have an existing, working board already.  

(its more or less a hybrid, all-in-one, Arduino and Waveshield in one small SMT board)

The board works as intended.. however I plan to get some of these assembled by a 3rd party (so I dont have to assemble by hand and re-flow in a toaster oven any more) to get some large batches made, and I want to improve on the quality of the audio output.

Here is some background where I tried to learn/play with LTSpice to adjust the hi/lo pass filters.
http://forum.arduino.cc/index.php?topic=373870.0

LTSpice just made things more confusing for me.. and in the end not much better than what I started out with.

So I am looking for some help/guidance to make my current hi/lo pass filters BETTER to improve quality than what I am getting now.  (It needs to be able to play a range of audio from hi's to low's without hiss/pop..etc)  ** I have some sample .wav files if needed for testing)

The board can/will not be changed.. it is what it is.  (So suggestions/solutions of change this to that that requires a new PCB or large change isnt going to be entertained)..

The pcb/schematic that pertains to the project in posted above in the other thread...

Its basically:

Low-Pass Filter:
R8 =  
C18 =
Voltage Divider:
R5 =
R6 =
High-Pass Filter:
C21 =

these values that I am looking for BETTER QUALITY/performance than I am currently getting.

If you look at the other thread.. you will see (read) that I have a DEMO board set up.. with little female headers come from the pads.  This is so I can 'plug-in' different combinations of values and test the results.

This is what I will do for your suggested answer/values as well.. if it works out and sounds great.. you get the loot!

I know its on the small side of projects, but I do believe in paying for the help regardless (for time and effort at least)..  **(IF THE SUGGESTIONS MAKE THINGS SOUND BETTER)

I'm posting in the paying gigs because:

1.)  I am bit turned off by LTSPice, and using it as a tool for helping me achieve my goal here
2.) I want to send out to get a batch of these made by some 3rd party Chinese assembly shop, so dont want to have to 'fix' anything after the fact.  :)
3.) Paying so its someone else responsibility for the hi/lo stuff!   haha

Let me know if you are interested.  (PM or post here with questions/interst)


thanks!
-xl






patduino

Hi XI97,

Sorry, just not an audio SME.  Looks interesting though.


Pat.
There are 10 types of people in the world, those who understand binary, and those that don't.

xl97

No worries! :)

I was just wondering if something I said turned people off to replying?  If it reads ok to you, I'll take your word for it! :)

(thanks for the replying regardless)

Nishant_Sood

Quote
The board works as intended.. however I plan to get some of these assembled by a 3rd party (so I dont have to assemble by hand and re-flow in a toaster oven any more) to get some large batches made, and I want to improve on the quality of the audio output.
If you anytime need to get help with manufacturing and assembling then I can do it, if you already have someone then its fine!
"Real Men can Accomplish  Anything"

- skype : nishants5  
ਫ਼ਤੇਹ ਕਰੁਂ!
www.winacro.com

xl97

Thanks!

I have not yet gotten to that step.  I still am doing small batches at a time by myself.

ie:

I cut a solder paste stencil on my vinyl cutter  (works great highly recommended)
manually place my components
bake/re-flow in my toaster oven.

but I rarely do more than say 5 at time or so.


That being said it is worth hearing what your set-up/requirements are! :)

Do you have a minimal board count?
Prices? (based on?)

its a small, single sided board assembly needed only, (dont know the part count off hand maybe around 40 or so parts give or take a few, mostly 0603 caps/resistors, ATmega328 SMD..etc)  (other side only contains a micro SD card socket, which I will solder by hand once I get my boards back)

I have been thinking about giving these guy a try:

http://blog.pcb.ng/now-with-less-volume/

but they only do 6 boards (meh)

I have been calculating at some other places recommended here or found through google.. and things didnt seem 'too' bad.. but I have never outsourced this before.

heres a pic of the board:  (next to an adafruit wave shield)

http://dmstudios.net/misc/scab_assembly/all-in-one_2.jpg

Let me know!

thanks!


* (I need to reply to a PM, as I just got back from vacation, and hopefully I can get the hi/lo pass filter stuff straightened out and be ready for this next step!)



Nishant_Sood

Quote
That being said it is worth hearing what your set-up/requirements are! :)

Do you have a minimal board count?
Prices? (based on?)

its a small, single sided board assembly needed only, (dont know the part count off hand maybe around 40 or so parts give or take a few, mostly 0603 caps/resistors, ATmega328 SMD..etc)  (other side only contains a micro SD card socket, which I will solder by hand once I get my boards back)

I have been thinking about giving these guy a try:

http://blog.pcb.ng/now-with-less-volume/

but they only do 6 boards (meh)
With me you can have all the flexibility you want, from 2 boards assembly to 2million!, My setup starts from a very simple single or double sided PCB with 6 to 8mils of track space to around 3 to 5 mils of track space and via to via spacing and surface finishHAL(snpb), Lead Free HAL, ENIG , Immersion Tin with 100% e-test included in the pricing. so cost depends on how hard your tech is to manufacture but yours seems easy(just telling that we can do the harder parts too!)

You can go down to 0402 or even 0201 parts with me without much added costs at all and can have soldering of ics like QFN BGA package also done successfully.
"Real Men can Accomplish  Anything"

- skype : nishants5  
ਫ਼ਤੇਹ ਕਰੁਂ!
www.winacro.com

xl97

Thanks.. I'll probably tap you to for some assembly, (once I get this hi-lo pass filter stuff sorted out!!!)

Its a bit beyond me all this audio stuff still  (in practice at least)..... hence the post.

Where are you located?  What are shipping costs?

allanhurst

Adjusting filters by altering comonents isn't very hard - but I need specs of the filter requirements and the hardware you're using

regards

Allan

xl97

Here is a thread where I was trying to use LTSpice to learn more about the hi-lo filter stuff..

It turned into more questions about how to use LTSpice, more than getting help with my filters!  lol

I was basically frustrated and gave up trying to get the right combination.

But this thread has more info and schematics..etc..etc

https://forum.arduino.cc/index.php?topic=373870.0


if there is any missing info.. ask.

I have a set-up I can get going to test values again if needed.


thanks

allanhurst

I can't find the schematic - could you re-post it?

regards

Allan

xl97

it was in first post, 3rd pic.

schematic of the DAC/AMP/filter stuff:

http://dmstudios.net/misc/amp_filter_values/amp_values1.jpg


lots of good background info there as well..  to see what has been used before..etc

to be clear.. it works.   But it can sound better.  There is where the project requirements com into play.  I have it working.. and it sounds OK..  but can sound better.   I dont want to GUESS at the values.  (need someone with more experience)

thanks.





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