Combining a digital dsp with analog crossovers are not always a good idea

[Tangband]

At faktiskt.io, a swedish hifi forum they have tested the new minidsp in a very expensive system . The result didnt come out well soundwise.

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In my opinion , trying to combine a dsp with analog crossovers are not always a good idea . Everything you put in between a source and a speaker makes the sound slightly worse . It may be passive crossovers, cables , AD converters , digital gain structure and more .

Im surprised that the reviewers at faktiskt.io dont draw the conclusion or think about the reason why it might sound worse putting a dsp in a signal chain with passive loudspeakers .

My experience - Im not suprised at all. No gear , analog or digital are fully transparent to the ear . One of the worst offender is passive crossovers in loudspeakers .

To gain real benefits with a dsp, one should instead go fully active with the minidsp - with all the crossovers in the digital domain and no passive coils, resistors or capacitors in the signal path. The source ( for example a computer with a DDC) would then go directly to the digital input of the Minidsp SHD. No A/D:s involved. No external DAC outside the minidsp is needed.

This way one can gain real sound improvements .

As I said in the beginning - buying a dsp to correct an analog loudspeaker is often a waste of money or time . The first step for real improvements would instead be converting the passive crossover in the passive loudspeaker to be fully active in the digital domain , keeping the signal digital as long as one possible can, and doing the crossover in the digital domain without converting it first to analog.

Whats your experience ?

 

[antcollinet]

My experience is using the MiniDSP flex in 2.0 with passive speakers has made a huge improvement.

Could it be better if I converted the speakers to active crossovers? Maybe - but I don't feel the need.

 

[Tangband]

My experience is using the MiniDSP flex in 2.0 with passive speakers has made a huge improvement.

Could it be better if I converted the speakers to active crossovers? Maybe - but I don't feel the need.

You havent tried it, so I understand.

 

[voodooless]

But this is not about active being better, it’s about enhancing a passing speaker with DSP.

I don’t see why this could not be beneficial. Just for room correction alone it should be worth it. For correcting certain speaker errors it should also work well.

For this one story showing they did not like it, I can probably find multiple that say the opposite. @tonycollinet already did. What does this prove? Absolutely nothing…

 

[antcollinet]

You havent tried it, so I understand.

Sort of counters your "waste of time and money" statement though. As does the experience of many here who have used DSP with "analogue" speakers.

 

[Tangband]

But this is not about active being better, it’s about enhancing a passing speaker with DSP.

I don’t see why this could not be beneficial. Just for room correction alone it should be worth it. For correcting certain speaker errors it should also work well.

For this one story showing they did not like it, I can probably find multiple that say the opposite. @tonycollinet already did. What does this prove? Absolutely nothing…

True - it wasnt a blind test, but very experienced listener ( 3 ) did the listening. They speculate that the internal SRC in minidsp would not be good enough. I can believe in some of that, at the same time theres much bigger faults with passive crossovers, even good active analog crossovers have much bigger issues than a dsp crossover.

 

[Cars-N-Cans]

DSP is simply a tool in this context. Its not something you put in to make things "sound better", its something you employ to correct certain aspects of rooms and speakers that would otherwise be impossible to fix.

 

[Tangband]

DSP is simply a tool in this context. Its not something you put in to make things "sound better", its something you employ to correct certain aspects of rooms and speakers that would otherwise be impossible to fix.

True, but at the same time a dsp has SRC, A/D:s and D/A:s . Do you really think every dsp crossover is transparent in bypass mode ( the signal goes thru the dsp ) ?
Many people on this forum reports that the cheapest minidsp is not good enough .

 

[Cars-N-Cans]

True, but at the same time a dsp has SRC, A/D:s and D/A:s . Do you really think every dsp crossover is transparent in bypass mode ( the signal goes thru the dsp ) ?
Many people on this forum reports that the cheapest minidsp is not good enough .

Hence why having proper specs backed by comprehensive measurements is so important given all the moving parts that are in a typical audio setup.

 

[Tangband]

Sort of counters your "waste of time and money" statement though. As does the experience of many here who have used DSP with "analogue" speakers.

In my opinion - The analog crossovers often hides the soundquality gains that can be had . One can ofcourse be happy with that .

 

[voodooless]

True - it wasnt a blind test, but very experienced listener ( 3 ) did the listening.

We know that self proclaimed experienced listener audiophiles in actuality do not listen very well compared to professional trained listeners. And who did the setup? Was it done properly? Can we verify that it objectively should have done a better job?

They speculate that the internal SRC in minidsp would not be good enough.

Nonsense.

 

[Tangband]

We know that self proclaimed experienced listener audiophiles in actuality do not listen very well compared to professional trained listeners. And who did the setup? Was it done properly? Can we verify that it objectively should have done a better job?

Nonsense.

You might be right in this case, or not.

 

[voodooless]

You might be right in this case, or not.

It’s a 200+ page topic spanning more than a decade. One would think they would have tested the hypothesis of the non-transparent ASRC by now..

 

[kongwee]

Minidsp don't specify the propagation bandwith. Class A, AB, D can easily achieve 600khz. It is not that you can hear 600khz. You can start stop a drive at 600khz.

Make a mistake it should be 600kHz than 600Mhz

 

[ZolaIII]

DSP helps a lot as long as you respect physical limitations of analog transmitters (driver's) used and how it's pasive crossover implemented.
It won't cure really bad space problems nor it can compensate for bad implemented crossover (analog or digital), at best it can help partially and in a ±3 dB limit.
Problem is that designer's usually exaggerate putting crossover to high for particular driver trying to get more from it than it can really do so the mids get recessed and edgy. There are two approaches in correcting it either cut it's low end with high pass filter (and re directing it to sub of course) or lowering the bass response (low self) level to match mids deficiency both resulting in relaxin it and improving it's response. Real cure is of course proper engineering (putting a low pass before driver starts to ring [more or less influenced and by cabinet design], and using a good old three way design). Unfortunately trend is other way around; cutting cost, pushing limits and staying on two or (God forbid) 2.5 way design's.
Digital domain simply gives you more space (to play around) and saves time in design process, once done properly it doesn't matter if it's active or pasive. What modern DSP done on FP calculations does great is making talks about SINAD and impact of the processing on signal quality obsolete but only in the digital domain of course.

 

[Frgirard]

True - it wasnt a blind test, but very experienced listener ( 3 ) did the listening. They speculate that the internal SRC in minidsp would not be good enough. I can believe in some of that, at the same time theres much bigger faults with passive crossovers, even good active analog crossovers have much bigger issues than a dsp crossover.

should you laugh?

 

[antcollinet]

It is not that you can hear 600mhz

No shit

 

[voodooless]

No shit

On the contrary, it’s a lot of shit

 

[antcollinet]

On the contrary, it’s a lot of shit

I'd sort of assumed the facepalm was redundant

 

[voodooless]

Minidsp don't specify the propagation bandwith.

That’s because “propagation bandwidth” is not a thing. It doesn’t exist