I am building an active analogue crossover for a 2-way infinite-baffle speaker. I have measurements and I'd like to prototype and test some possible active crossovers in the digital domain.
Available hardware is a Motu M2 and microphone, several MacBooks running OsX and Ubuntu, a vinyl front end, amplification including a pair of power amplifiers.
I presume a second DAC and software could enable this? Or some DSP crossover.
Objective is to test candidate analogue filters, so their absolute sound quality is less of an issue than the ease of modifying parameters.
Does this make sense?
Can you suggest suitable tools / software / components?
TIA!
Available hardware is a Motu M2 and microphone, several MacBooks running OsX and Ubuntu, a vinyl front end, amplification including a pair of power amplifiers.
I presume a second DAC and software could enable this? Or some DSP crossover.
Objective is to test candidate analogue filters, so their absolute sound quality is less of an issue than the ease of modifying parameters.
Does this make sense?
Can you suggest suitable tools / software / components?
TIA!
I've only got one stereo out, so I need at least 2 more DAC channels.
Rew and VituixCAD are useful for design but can implement digital filters in EQ Apo?
By prototyping filters, I mean to take an analogue feed, digitise it, run it through digital versions of analogue filters, DACs, and output 4 analogue channels to my speakers.
Rew and VituixCAD are useful for design but can implement digital filters in EQ Apo?
By prototyping filters, I mean to take an analogue feed, digitise it, run it through digital versions of analogue filters, DACs, and output 4 analogue channels to my speakers.
Yes, software DSP is handy if you have the outputs.
While VC does emulate different brands, I don't think it matters as long as you have a target curve for each range. You can realise it on your own working with the filter software. Then evaluate and approve a set of curves.
I'd presume you'd have already used simulation.. I mean that's a separate thing to this necessary for the speaker itself.
While VC does emulate different brands, I don't think it matters as long as you have a target curve for each range. You can realise it on your own working with the filter software. Then evaluate and approve a set of curves.
Yes, I need a software DSP in which to build and use the filters I've designed (using VituixCAD, REW etc) with either a 4-channel DAC or a second 2-channel DAC (is the Topping D10s still the go-to choice?) for the output.
If the DSP can output to separate devices that helps.
Any suggestions for a software DSP?
Setting output gain on the Motu is a pita as they are controlled by a knob and the only way to keep it constant is to tape it down. So I'd be open to a better DAC. Thoughts?
If the DSP can output to separate devices that helps.
Any suggestions for a software DSP?
Setting output gain on the Motu is a pita as they are controlled by a knob and the only way to keep it constant is to tape it down. So I'd be open to a better DAC. Thoughts?
It sounds like you have your answers and don't need more hardware but I still want to send a shout-out to miniDSP for the excellent, easy to use and easy to understand user interfaces.
Got a few answers thanks👍
@fb CamillaDSP looks interesting. I'll have a play with it. Command line is fine with me. Any limitations or usage issues I should be aware of?
@AllenB Had a quick look at T5's program which covers the basics with Butterworth filters up to 4th order, Linkwitz-Riley 12dB and 24dB plus a couple of other things.
@eriksquires I looked into miniDSP - the miniDSP 2x4 for active 2-way could be quick to get up and running. What's it like going from analogue filter parameters to miniDSP and back again? It seems you select a frequency, order and type? Does this cover all the bases?
@fb CamillaDSP looks interesting. I'll have a play with it. Command line is fine with me. Any limitations or usage issues I should be aware of?
@AllenB Had a quick look at T5's program which covers the basics with Butterworth filters up to 4th order, Linkwitz-Riley 12dB and 24dB plus a couple of other things.
@eriksquires I looked into miniDSP - the miniDSP 2x4 for active 2-way could be quick to get up and running. What's it like going from analogue filter parameters to miniDSP and back again? It seems you select a frequency, order and type? Does this cover all the bases?
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My experience is with Hypex Filter Designer and miniDSP, but not exactly the same application. With Hypex I used a 3 channel plate amp for a center speaker. With miniDSP I mostly use it for the subwoofer LP filter and EQ. I just found that turning things on or off, and knowing what the DSP was doing was a lot more clear with miniDSP than Hypex. Hypex to me still feels like an alpha release product. It's not "buggy" but just very uncomfortable. Grabbing a hold of a specific filter was much easier with miniDSP for instance.
It's been a while since I used miniDSP, but in addition to basic filters you can also enter the numbers straight from OmniMic or VirtuixCAD or REW for any parametric filters, shelving or LP/HP filters. Especially handy if you let software attempt to optimize a number of filters for you.
Ok so it sounds like miniDSP should enable me to map any analogue filter in digital.
Any thoughts on CamillaDSP?
Any thoughts on CamillaDSP?
If you are looking to implement filters you plan on converting to analog, line level then yes, the miniDSP will work, generally. Theprobles will happen when you realize how versatile and easy it is to do things with DSP like LR4 with digital delay. 🤣
Most any DSP will do that.
Camilla is currently the most supported project of it's type here, and is usually at the top of the PC Based subforum. You could wet your toes over on that thread.
I've read around the miniDSP site and elsewhere; whilst everything else looks good, it seems the miniDSP 2x4 HD may have quite a high noise level which would affect its HF output, compared to the better DACs. And an HF droop.
CamillaDSP also looks good. As I can't mix and match 2-channel DACs as there will be different signal delays due to asynchronous transmission, I'm looking for suggestions for 4-channel DACs?
CamillaDSP also looks good. As I can't mix and match 2-channel DACs as there will be different signal delays due to asynchronous transmission, I'm looking for suggestions for 4-channel DACs?
The miniDSP 2x4 HD has a signal to noise ratio of better that 12dB if properly set up.
@deercreekaudio Or 120dB 😅
Thanks for the graph, that looks absolutely fine for my purposes.
Properly setup = good quality shielded RCA cables and a low-noise 12V power supply - battery? Or mains?
Thanks for the graph, that looks absolutely fine for my purposes.
Properly setup = good quality shielded RCA cables and a low-noise 12V power supply - battery? Or mains?
The power supply provided by miniDSP allows the full performance of the 2x4HD. Plus, the 2x4HDs have very good internal voltage regulation.
I use Sigma Studio and an AD evaluation kit for the development of analog active crossovers.
One has to be aware that IIR filters do not exactly represent their analog counterparts due to the warping of the frequency axis. Because this is mostly noticeable at the upper end of the spectrum it can be partly mitigated by the use of high sampling rates.
Regards
Charles
One has to be aware that IIR filters do not exactly represent their analog counterparts due to the warping of the frequency axis. Because this is mostly noticeable at the upper end of the spectrum it can be partly mitigated by the use of high sampling rates.
Regards
Charles