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TOPIC: Re: OpenDRC

OpenDRC 7 years 9 months ago #4294

  • KAMIKAZE
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Q:
This product can filter FIR only with stereo signal? So, can you give examples how I can use it? Well, I want stereo 4-way FIR filtered system... I can create it with 2x8. How OpenDRC can help me with FIR?

Whatever, FIR is a very good. Looking forward for new products.
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Re: OpenDRC 7 years 9 months ago #4296

  • curryman
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You can not perform FIR filtering with 2x8 (I think you wanted to write that, didn't you ;) ). Thus linear phase EQ is not possible with existing 2x8 hardware. OpenDRC could be used to "preprocess" the data before going into 2x8 in order to realize linear phase filtering.

Though I'd also really love to see a 6 or 8 channel OpenDRC ;) Looking forward to further exciting products from miniDSP!
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Re: OpenDRC 7 years 9 months ago #4299

  • KAMIKAZE
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For sure :) 2x8 FIR, any other perhaps not that most DIY wants.
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Re: OpenDRC 7 years 9 months ago #4305

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@ Kamikaze,

4way FIR filtering wouldn't be possible with an OpenDRC-DI platform since it's only a stereo. 4 way stereo = 4 times the amount of power required to make it happen and a different plug-in.

Maybe in the future. It's only the beginning of a new wave, so patience new things will come.. :-)

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Re: OpenDRC 7 years 9 months ago #4311

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Very interesting product.

I really like the possibilities of this product, and have some questions regarding the ADSP platform you are using.

Will this product be available without cabinet, knobs and connectors (like the miniDSP) – just the pure PCB with an expansion port (like the miniDSP)?? Maybe even at a reduced price?

Does the OpenDRC use the ADSP21369 ASRC and SP-DIF transceivers and will there be an expansion port with access to more transceivers and ASRC´s (opening a possibility for a 2-way system)?

You use an ASRC allowing a wide range of input streams (20 to 216khz). As I understand the internal processing sample rate is also selectable (you specify filter lengths for 48 and 96khz). How low sample rate can the ASRC deliver to the ADSP??

The reason for these questions is that I have at 2 way system in mind working at two different sample rates (fs) (fs here is the internal sample rate from the ASRC to the DSP). One sample rate (fs = 48 or 96khz) working on the high frequency content and one sample rate (fs around 12khz) used for the low frequency content. This will allow for at filterlength of 16.000 running at fs=12khz (frequency resolution of 0,75hz) and a filterlength of 2.100 running af fs=48khz (frequency resolution of 22).

This idea would require your platform to use two ASRC and two SPDIF transceivers, but would give a great frequency resolution in the lower frequencies, whereas your 6.144 tap filter at fs=48khz would not have enough frequency resolution (8hz) to be used for room correction in the very low frequency range (in my opinion).

Kind regards
Hans, Denmark
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Re: OpenDRC 7 years 9 months ago #4312

  • KAMIKAZE
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4 way stereo = 4 times the amount of power required to make it happen and a different plug-in.
You can create our own FPGA based DSP signal chain, so it is no will be a standard DSP processor. Thats do holmacoustics.com/ and they have FIR's for 3-way system already.
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Re: OpenDRC 7 years 9 months ago #4317

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@Jakster:
I had the same idea and would really appreciate this (see my previous post), however the currently announced OpenDRC is purely Stereo (2ch in, 2ch out).

The DSP used for this platform has 8 sample rate converters build in, that should enable the functionality you asked for ;-)

Whenever DevTeam said something like "Maybe in the future,.. Beginning of a new wave..." it was worth waiting ;-)
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Re: OpenDRC 7 years 9 months ago #4320

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DevTeam,

What software are you intending people to use to calculate the FIR filters?

Also, what is the latency of the system?

:)
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Re: OpenDRC 7 years 9 months ago #4327

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@ Jakster,

Thanks for your interest. It's quite early on in the product release and a lot more information will be released after CES tradeshow. With this said, here is a bit more info:

- A kit version will eventually be released.
- ASRC is up and downsampling so it's as per datasheet 20-216k. :-)
- Fs will be 48kHz for default configuration. In the future, we'll release some 96k configuration. No release time but with this said a DSP core always operate at ONE sampling frequency. (i.e. code compiled to run at one sampling frequency). That's why we have the SRC at input, to accept any sample rate. Your idea of running the DSP at 2 frequency is so called decimation and isn't happening on this platform by default. Maybe in the future or maybe a smarter way to perform efficiency without decimation.

FYI, this is a new product, so many features to be developed over time. :-)

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Re: OpenDRC 7 years 9 months ago #4328

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@FindBuddha,

Further information is about to be released about our software partners. We're put that info live by middle of today or end of the week end if all goes well.

If you already have your own FIR filter software platform, you can load filter (copy paste or .bin IEEE754 format) like the advanced plug-ins. Hence the "open" DSP concept. :-)

As for latency, it depends on your FIR filter length. (calculation available online). Our internal latency without the FIR is about 3-4ms.

DevTeam
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Last Edit: 7 years 9 months ago by devteam.
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Re: OpenDRC 7 years 9 months ago #4341

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@Curryman
Thanks

@Devteam
Thank you for replying. A few comments (I write in blue - sorry for not quoting properly)


Thanks for your interest. It's quite early on in the product release and a lot more information will be released after CES tradeshow. With this said, here is a bit more info:

- A kit version will eventually be released.
- ASRC is up and downsampling so it's as per datasheet 20-216k. :-)

I know – the question was regarding the lowest possible sampling frequency between ASRC and DSP (fs) – not the “external sampling frequency”.

- Fs will be 48kHz for default configuration. In the future, we'll release some 96k configuration. No release time but with this said a DSP core always operate at ONE sampling frequency. (i.e. code compiled to run at one sampling frequency). That's why we have the SRC at input, to accept any sample rate. Your idea of running the DSP at 2 frequency is so called decimation and isn't happening on this platform by default. Maybe in the future or maybe a smarter way to perform efficiency without decimation.

I´m not sure I follow (maybe it´s language barrier - i´m danish). The core frequency of the ADSP is 333Mhz producing 2.4 Gflops. Those 2.4 Gflops can be used at any audio sample frequency (fs) or several sampling frequencies (fs1, fs2 fs3…). It requires separate filters and interrupt routines for each fs – but is possible. I did a project 9 years ago on a TMS320C6711 running a multirate 3 way system (granted we did the downsampling and upsampling in code and not in hardware, but still). Do you mean, that the code you have written does not support multiple sample rates??

Running multirate audio correction using hardware resampling requires access to more receivers and ASRC´s and I don´t know if your PCB layout supports the use of more than one receiver and ASRC?

That said, I really look forward to seeing where you´re going to go with this platform.

/Hans








FYI, this is a new product, so many features to be developed over time. :-)

DevTeam[/quote]
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Re: OpenDRC 7 years 9 months ago #4345

  • curryman
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As you already mentioned in an earlier post, the DSP used on this platform already has build in ASRC (8ch!). Even if an additional external ASCR is used for the input, the ASRCs build into the DSP could be used to run multirate audio correction and the last sentence from miniDSP lets me hope that this will be realized in the future ;)
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Re: OpenDRC 7 years 9 months ago #4367

  • KAMIKAZE
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Also Pioneer already have RS-P99 www.pioneer.eu/eur/products/25/29/182/RS-P99/specs.html

- 4-way, L/R independent
- FIR Filter
- Electronic DAC volume
- S/N ratio 115dB

And all this it a car. By the way, Analog Devices have released new chips, I think it really can help to build 4-way FIR system much easy.
Also RS-P99 use 3 ADSP-21065L and they can fit too even now.

This can be hi-end minidsp board, as many DIY requested.
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Re: OpenDRC 7 years 9 months ago #4368

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@ kamikaze

Good find - I never thought to look for DSP processing power in a car audio solution.

However - have you seen the pricetag on RS-P99?? The Danish price is above 2500 euro which is quite costly.

Secondly which new chips from analog are you referring to?

The ADSP-21065L is a lot slower than OpenDRC´s ADSP-21369 (0,2GFlops vs. 2,4 GFlops) - looks slighty cheaper though.
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Re: OpenDRC 7 years 9 months ago #4369

  • KAMIKAZE
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Price, yes. They are brand. Also old model RS-P90 can be found for above $1-$1.3k.
Check here www.analog.com/en/processors-dsp/sharc/products/index.html
www.analog.com/en/processors-dsp/sharc/p...e/resources/fca.html
I don't know what exactly chip suitable to FIR, however AD have such enough performance chips.
Pioneer did 4-way FIR processing on them old versions.

Chip used in P99 was published in 2003year :D (if we see on DATA SHEET publishing date)
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