Crossover filtering

Writing software that inputs and/or outputs audio and performs DSP algorithms such as filters, new codecs or audio effects.
Post Reply
shawnrk
User
Posts: 3
Joined: Fri 2016-03-04 19:18

Crossover filtering

Post by shawnrk » Fri 2016-03-04 19:31

Hello,
I’m designing a consumer audio product that will have mono operation with a 2-way speaker design. I would like to implement crossover filtering in the digital domain within a VLSI chip such that the left channel is high-pass filtered (and fed to the tweeter) and the right channel is low-pass filtered (and fed to the woofer). Can this sort of real-time filtering be accomplished on the vs1000, or would I have to step up to a vs1063 or even the vs1005?

Thank you!

Best regards, Shawn

User avatar
Panu
VLSI Staff
Posts: 2354
Joined: Tue 2010-06-22 13:43

Re: Crossover filtering

Post by Panu » Sat 2016-03-05 7:12

We have a ready made board for that, the VS1005 Amp Board. It even contains the power amplifier for the speaker elements. You can experiment all sorts of crossover filters with that board, plus anything else the VS1005 and the VSOS can do. You can even use it to play MP3 files from a microSD card.

VS1000 can't be used for that purpose since it has no input. VS1053 could be used but we don't have the software. But for VS1005 everything is ready. You could start production immediately when you have the casing ready and the speaker elements chosen.

-Panu
Info: Line In and Line Out, VS1000 User interface, Overlay howto, Latest VSIDE, MCU Howto, Youtube
Panu-Kristian Poiksalo, VLSI Solution Oy

shawnrk
User
Posts: 3
Joined: Fri 2016-03-04 19:18

Re: Crossover filtering

Post by shawnrk » Sun 2016-03-06 5:48

Hello Panu,
Thank you for the prompt reply! My product does not require an input (it will play solely from the SD card). Given that, it sounds like the VS1000 is technically capable of crossover filtering. Additionally, since I'm only playing from the SD card, I suppose I can accomplish this by filtering the audio files on the PC (ie, mix to mono, then highpass left channel and lowpass right channel) before even loading them to the device over USB (I'm writing the PC sync software as well). But as a failsafe, I would feel a lot better if the DSP were doing the filtering rather than relying on the proper filtering of the music files.

I am undecided on which chip to use. There are definitely a couple of additional features that I could implement with the 1005 that would not be possible with the 1000 (owing to the RTC). I assume the 1005 will be a bit more future-proof since it is a newer chip and OS. So I may lean that way anyway. Has an EOL date been announced for the vs1000?

The 1005 amp board is very interesting - I may get one for development purposes. Is there a schematic available for this board? I'm particularly interested in what amp IC is being used.

Enjoy the rest of your weekend!

Thanks, Shawn

User avatar
Panu
VLSI Staff
Posts: 2354
Joined: Tue 2010-06-22 13:43

Re: Crossover filtering

Post by Panu » Sun 2016-03-06 19:11

Hi!

Hmm, although technically possible, implementing said functions (USB SD Card Player + crossover filtering) to the VS1000 might be a daunting task, mainly due to the limited (8KB) program memory available. Also, you will be limited to Ogg Vorbis file format.

My choice would be to make it for the VS1005 at first since that's relatively easy, basically just reconfiguring software which is already written. Then if it proves successful in the market, you can retarget it to for example VS1000 for cost-down.

VS1000 is in full production and selling very well. No EOL is planned. But it's best suited for long term projects with large sales quantities, because it takes a long time to develop new software for the VS1000.

-Panu
Info: Line In and Line Out, VS1000 User interface, Overlay howto, Latest VSIDE, MCU Howto, Youtube
Panu-Kristian Poiksalo, VLSI Solution Oy

shawnrk
User
Posts: 3
Joined: Fri 2016-03-04 19:18

Re: Crossover filtering

Post by shawnrk » Mon 2016-03-07 16:17

Hi Panu,
Ok that makes the decision for me - I will proceed with the VS1005. Also, can I get the documentation for the amp board before I order it (including hopefully a schematic)? I cannot find it on the website.

Thanks very much, Shawn

User avatar
Panu
VLSI Staff
Posts: 2354
Joined: Tue 2010-06-22 13:43

Re: Crossover filtering

Post by Panu » Tue 2016-03-08 18:39

Hi!

Seems the guys want to still write some more software for the board before releasing it. But we'll set up a web page shortly.

-Panu
Info: Line In and Line Out, VS1000 User interface, Overlay howto, Latest VSIDE, MCU Howto, Youtube
Panu-Kristian Poiksalo, VLSI Solution Oy

Post Reply

Who is online

Users browsing this forum: No registered users