System architecture

[fbirch]

Not sure if this is the correct sub forum, but I intend to build a 2-channel system for music only, no HT, and would like the advice of folks here on the overall architecture. The basic elements I think I’ll need are:

Sources:
Streamer running Tidal and FLAC library of ripped CDs – looking at the Eversolo A6 Gen 2
Multi-format disc player – currently have a SONY UBP-X800M2
Turntable – currently have an old Technics unit that I use infrequently
High quality amplifier - TBD
Speakers – looking at the Revel F226Be floorstander
Subwoofer – 1 or a stereo pair, currently have one JL Audio D108, which is an 8-inch active unit, open to adding a 2nd one

To cross over the sub and floorstanders, I’ll either an external DSP, a preamp that has a built-in sub crossover function, or possibly both.

My questions are:

Is it acoustically transparent to put a DSP in between a preamp output and the amp input? See first figure

Is it better to do the crossover function all in the digital domain before ever converting to analog? See 2nd figure
Is it possible to use an all-in-one Streamer/DSP/EQ/crossover that accepts other inputs, thus eliminating a dedicated preamp altogether? See 3rd figure

 

[alex-z]

Yes, a good quality DSP unit is acoustically transparent.

Yes, doing the speaker/subwoofer crossover in the digital domain is ideal. Analogue subwoofer integration has far less control over time alignment and room correction.

Some streamers like Wiim Ultra do have a phono stage. However the analogue to digital converter is a bit mediocre. Only your turntable should be routed via the pre-amp, your streamer and disc player should be hooked up digitally.

WiiM Ultra Streamer Preamp Review

This is a review and detailed measurements of the WiiM Ultra network streamer, DAC, phono stage and preamplifier. It was sent to me by the company and costs US $329. Physical attribute are modern and attractive enough. Alas, I can't say the same thing about the graphical interface. Icons seem...

www.audiosciencereview.com

I would strongly advise against the EverSolo A6 Gen 2. $1300 for a device with only 2 analogue outputs is absurd, you don't have a proper way to integrate the subs. A miniDSP Flex Balanced + WiiM Pro Plus gives you more functionality for $800 total.

Minidsp Flex Review (Audio DSP)

This is a review and detailed measurement of the Minidsp Flex audio signal processor. It was sent to me by the company and costs US $475 for unbalanced and $550 for balanced that I tested. Flex borrows the interface from SHD and puts it in a compact package. Seeing how I really liked that...

www.audiosciencereview.com

WiiM Pro Plus Streamer Review

This is a review and detailed measurements of the WiiM Pro Plus streamer, DAC and preamplifier with Bluetooth support. It was sent to me by the company and costs US $219. While the case is plastic, it still "looks the part" as the Brits would say relative to other more famous brands of...

www.audiosciencereview.com

Even adding a brand new phono pre-amp + ADC unit is still only $1100 total.

2 subs is substantially better than 1, with the caveat that you should run them as a mono signal. With a normal 80Hz crossover you do not significantly impact stereo imaging with stereo subs. However the benefits to room mode management are substantial, resulting in a smoother bass response.


I would also recommend larger subwoofers. The D108 is a good quality unit, but the factory tuning sacrifices dynamic range for bass extension. An 8" driver in a sealed cabinet can only do so much even with 500 watts. There are units like the SVS SB-1000 Pro or Rythmik L12 with significantly more output.

 

[Keith_W]

Is it acoustically transparent to put a DSP in between a preamp output and the amp input? See first figure

The danger is that you will clip the ADC on the DSP unit if you have a preamp upstream. You do not need a preamp, you can do the volume control with your DSP unit. And yes, good ADC's are transparent to below audible limits.

Is it better to do the crossover function all in the digital domain before ever converting to analog? See 2nd figure
Is it possible to use an all-in-one Streamer/DSP/EQ/crossover that accepts other inputs, thus eliminating a dedicated preamp altogether? See 3rd figure

The answer to both questions is "yes", but I would not do it in the way you have drawn your diagrams. Problems with your diagrams:

Diagram 1: preamp is not needed.
Diagram 2: "Your streamer w/ EQ, XO, and DAC" is connected to the powered subwoofer without a volume control, while your other two sources go through the preamp. Doing this will mean that there is no volume control on the subwoofer. Or, if you configure your streamer to do volume control, it means there is no subwoofer for the CD transport and turntable.
Diagram 3: "Streamer with ADC, XO, DSP and DAC" - no such device exists as far as I am aware of.

Here is one potential solution:

All sources go through the interface, and sent to the PC for processing. The PC does the volume control and the DSP. It sends the output back out to the interface, which is connected to the amplifier and subwoofer. Examples of interfaces: RME Babyface Pro, RME Fireface UCX II, Motu Ultralite Mk. 5, Focusrite 4i4, Merging Anubis. This DSP setup has by far the most CPU power, which means you can use linear-phase FIR filter DSP with a huge number of taps.

And here is another:

"DSP Box" can be a MiniDSP, Danville Nexus, or some kind of contraption that you construct yourself if you have the skills.

 

[boxerfan88]

Is it better to do the crossover function all in the digital domain before ever converting to analog?

Personally i think so. I implemented exactly this in my recent HiFi upgrade, and I’m extremely pleased with the outcome.

In my setup, a Pc with foobar 64bit does all digital processing (digital capture/playback, resampling, room correction, subwoofer crossover, volume control).

Pc outputs 3channels to Topping DM7 DAC.

DAC to speakers/subwoofer.

Clean and simple. No multiple DA-AD-DA-AD-DA conversions, just one DA conversion and that’s it.

Mine is just one model out of many out there. It really depends on your use case.

 

[fbirch]

Yes, a good quality DSP unit is acoustically transparent.

Yes, doing the speaker/subwoofer crossover in the digital domain is ideal. Analogue subwoofer integration has far less control over time alignment and room correction.

Some streamers like Wiim Ultra do have a phono stage. However the analogue to digital converter is a bit mediocre. Only your turntable should be routed via the pre-amp, your streamer and disc player should be hooked up digitally.

WiiM Ultra Streamer Preamp Review

This is a review and detailed measurements of the WiiM Ultra network streamer, DAC, phono stage and preamplifier. It was sent to me by the company and costs US $329. Physical attribute are modern and attractive enough. Alas, I can't say the same thing about the graphical interface. Icons seem...

www.audiosciencereview.com

I would strongly advise against the EverSolo A6 Gen 2. $1300 for a device with only 2 analogue outputs is absurd, you don't have a proper way to integrate the subs. A miniDSP Flex Balanced + WiiM Pro Plus gives you more functionality for $800 total.

Minidsp Flex Review (Audio DSP)

This is a review and detailed measurement of the Minidsp Flex audio signal processor. It was sent to me by the company and costs US $475 for unbalanced and $550 for balanced that I tested. Flex borrows the interface from SHD and puts it in a compact package. Seeing how I really liked that...

www.audiosciencereview.com

WiiM Pro Plus Streamer Review

This is a review and detailed measurements of the WiiM Pro Plus streamer, DAC and preamplifier with Bluetooth support. It was sent to me by the company and costs US $219. While the case is plastic, it still "looks the part" as the Brits would say relative to other more famous brands of...

www.audiosciencereview.com

Even adding a brand new phono pre-amp + ADC unit is still only $1100 total.

2 subs is substantially better than 1, with the caveat that you should run them as a mono signal. With a normal 80Hz crossover you do not significantly impact stereo imaging with stereo subs. However the benefits to room mode management are substantial, resulting in a smoother bass response.


I would also recommend larger subwoofers. The D108 is a good quality unit, but the factory tuning sacrifices dynamic range for bass extension. An 8" driver in a sealed cabinet can only do so much even with 500 watts. There are units like the SVS SB-1000 Pro or Rythmik L12 with significantly more output.

Thanks for the feedback with the links. I looked at the link for the Wiim Ultra, and it seems to have everything I'd need to serve as an all-inclusive EQ, XO and preamp. I'm really intrigued by it as a possible solution for my setup. I have a few questions that you may perhaps be able to answer.

When you say the DAC is just so-so, I presume you mean for the phono input, since that's the only item where I'd need to input an analog signal to it. If so, I could route the turntable directly to a separate preamp as you suggest, or just live with slightly suboptimal turntable sound, since I use it very infrequently.

If routing turntable to a separate preamp and using the Wiim Ultra for EQ and XO functions, that means I'd have neither for turntable listening, correct?

If I route my disc player digital output into the Wiim Ultra, then I could use the Wiim Ultra's EQ and XO functions for streamed music + onboard/USB FLAC library + disc player music, correct?

Is the XO function of the Wiim Ultra fully user adjustable (cross over frequency, etc.)?

How good is the EQ?

Does the EQ function apply to the Wimm Ultra's analog AND digital outputs, or only the former? The preamp I'm looking at can accept both analog and digital inputs.

Thanks again for pointing out the Wiim Ultra as a possible solution for my needs. It seems almost too good to be true from a pricing standpoint. I like the ability to buy such a component at a low price, because this is the part of a modern system where technology is making the most rapid advances, and thus you are more likely to want to swap it out for something new after a couple years.

 

[fbirch]

The danger is that you will clip the ADC on the DSP unit if you have a preamp upstream. You do not need a preamp, you can do the volume control with your DSP unit. And yes, good ADC's are transparent to below audible limits.



The answer to both questions is "yes", but I would not do it in the way you have drawn your diagrams. Problems with your diagrams:

Diagram 1: preamp is not needed.
Diagram 2: "Your streamer w/ EQ, XO, and DAC" is connected to the powered subwoofer without a volume control, while your other two sources go through the preamp. Doing this will mean that there is no volume control on the subwoofer. Or, if you configure your streamer to do volume control, it means there is no subwoofer for the CD transport and turntable.
Diagram 3: "Streamer with ADC, XO, DSP and DAC" - no such device exists as far as I am aware of.

Here is one potential solution:

View attachment 433648
All sources go through the interface, and sent to the PC for processing. The PC does the volume control and the DSP. It sends the output back out to the interface, which is connected to the amplifier and subwoofer. Examples of interfaces: RME Babyface Pro, RME Fireface UCX II, Motu Ultralite Mk. 5, Focusrite 4i4, Merging Anubis. This DSP setup has by far the most CPU power, which means you can use linear-phase FIR filter DSP with a huge number of taps.

And here is another:

View attachment 433652

"DSP Box" can be a MiniDSP, Danville Nexus, or some kind of contraption that you construct yourself if you have the skills.

Thanks, and I can see that you are correct about the flaws in my diagrams.

The combo preamp/amp that I'm looking at has a preamp section with two full range RCA outputs, one of which is normally jumpered straight into the amp section input; the 2nd preamp out available for a powered sub with its own LP filter, I presume. What would be the downside to simply putting a passive HP filter between the preamp and power amp, and passive LP filter between the 2nd output and a powered sub? Set aside the matter of EQ for now (the preamp has an analog EQ, which I realize would only be good for very gross room correction).

The reality is that I listen to my music at 65-70 dB about 10 feet from the speakers. At that volume level, I doubt I'd be driving a Revel 226Be into LF distortion, even if I sent it a full range input with no crossover. But if there's a painless way to get XO functionality, I'd like to have it.

 

[fbirch]

Personally i think so. I implemented exactly this in my recent HiFi upgrade, and I’m extremely pleased with the outcome.

In my setup, a Pc with foobar 64bit does all digital processing (digital capture/playback, resampling, room correction, subwoofer crossover, volume control).

Pc outputs 3channels to Topping DM7 DAC.

DAC to speakers/subwoofer.

Clean and simple. No multiple DA-AD-DA-AD-DA conversions, just one DA conversion and that’s it.

Mine is just one model out of many out there. It really depends on your use case.

Thanks for feedback on your firsthand experience.

 

[alex-z]

Thanks for the feedback with the links. I looked at the link for the Wiim Ultra, and it seems to have everything I'd need to serve as an all-inclusive EQ, XO and preamp. I'm really intrigued by it as a possible solution for my setup. I have a few questions that you may perhaps be able to answer.

When you say the DAC is just so-so, I presume you mean for the phono input, since that's the only item where I'd need to input an analog signal to it. If so, I could route the turntable directly to a separate preamp as you suggest, or just live with slightly suboptimal turntable sound, since I use it very infrequently.

If routing turntable to a separate preamp and using the Wiim Ultra for EQ and XO functions, that means I'd have neither for turntable listening, correct?

If I route my disc player digital output into the Wiim Ultra, then I could use the Wiim Ultra's EQ and XO functions for streamed music + onboard/USB FLAC library + disc player music, correct?

Is the XO function of the Wiim Ultra fully user adjustable (cross over frequency, etc.)?

How good is the EQ?

Does the EQ function apply to the Wimm Ultra's analog AND digital outputs, or only the former? The preamp I'm looking at can accept both analog and digital inputs.

Thanks again for pointing out the Wiim Ultra as a possible solution for my needs. It seems almost too good to be true from a pricing standpoint. I like the ability to buy such a component at a low price, because this is the part of a modern system where technology is making the most rapid advances, and thus you are more likely to want to swap it out for something new after a couple years.

The DAC is great. The ADC and phono pre-amp stages are a bit mediocre. Not audibly bad, just something you might want to upgrade if your turntable usage was more frequent. Fosi X5 is excellent for only $110.

Fosi Audio Box X5 Phono Preamp Review

This is a review and detailed measurements of the Fosi Audio Box X5 stereo Phono stage. It was sent to me by the company and costs US $109.99. Company manages to bring a touch of class in a category that is universally utilitarian with those rounded corners and orange power button. Flexibility...

www.audiosciencereview.com

You would route the turntable into the phono pre-amp, and the pre-amp into the Wiim Ultra. You still retain EQ and subwoofer crossover in such a setup.

Yes, any digital input to a Wiim streamer gives you full functionality.

The crossover point can be set anywhere from 30 to 250Hz. There is 0/180 degree phase, delay control (1ms increment), and level adjust. The only thing you cannot change to my knowledge is the filter slope, that stays at 24dB per octave.

The EQ capability is a 7/10 in my opinion. You have parametric EQ control, including low-shelf and high-shelf if needed. It lacks mixed phase filters, so something like Dirac Live would have a higher performance ceiling. There is also only a single subwoofer output, so blending different subs, or doing per-sub time alignment is not possible.

The signal processing applies to analogue and digital outputs simultaneously. You can disable the signal processing but the outputs are mirrored.

Any pre-amp with a digital input is also a DAC, and therefore a waste of money in this sort of setup. The Wiim Ultra is an excellent DAC, and there is no reason for the pre-amp to be placed afterwards in the signal chain, because the Wiim Ultra will handle volume control for you.

Just to clarify, a turntable aka phono pre-amp serves a relatively simple purpose, boosting the voltage into a usable range for the rest of your signal chain. This also helps with noise rejection, the phono pre-amp should be as close to the turntable as possible with a short cable. The old school approach of having a "global" pre-amp for all sources is no longer needed, DSP can provide volume control while allowing your amplifier(s) to run at a fixed gain.

 

[fbirch]

The DAC is great. The ADC and phono pre-amp stages are a bit mediocre. Not audibly bad, just something you might want to upgrade if your turntable usage was more frequent. Fosi X5 is excellent for only $110.

Fosi Audio Box X5 Phono Preamp Review

This is a review and detailed measurements of the Fosi Audio Box X5 stereo Phono stage. It was sent to me by the company and costs US $109.99. Company manages to bring a touch of class in a category that is universally utilitarian with those rounded corners and orange power button. Flexibility...

www.audiosciencereview.com

You would route the turntable into the phono pre-amp, and the pre-amp into the Wiim Ultra. You still retain EQ and subwoofer crossover in such a setup.

Yes, any digital input to a Wiim streamer gives you full functionality.

The crossover point can be set anywhere from 30 to 250Hz. There is 0/180 degree phase, delay control (1ms increment), and level adjust. The only thing you cannot change to my knowledge is the filter slope, that stays at 24dB per octave.

The EQ capability is a 7/10 in my opinion. You have parametric EQ control, including low-shelf and high-shelf if needed. It lacks mixed phase filters, so something like Dirac Live would have a higher performance ceiling. There is also only a single subwoofer output, so blending different subs, or doing per-sub time alignment is not possible.

The signal processing applies to analogue and digital outputs simultaneously. You can disable the signal processing but the outputs are mirrored.

Any pre-amp with a digital input is also a DAC, and therefore a waste of money in this sort of setup. The Wiim Ultra is an excellent DAC, and there is no reason for the pre-amp to be placed afterwards in the signal chain, because the Wiim Ultra will handle volume control for you.

Just to clarify, a turntable aka phono pre-amp serves a relatively simple purpose, boosting the voltage into a usable range for the rest of your signal chain. This also helps with noise rejection, the phono pre-amp should be as close to the turntable as possible with a short cable. The old school approach of having a "global" pre-amp for all sources is no longer needed, DSP can provide volume control while allowing your amplifier(s) to run at a fixed gain.

Extremely helpful! Thank you so much.

 

[digitalfrost]

Regarding Slide 3, this is more or less what I have, it exists, and it's called a PC.

I run DSP in the PC, I use it for to play back digital sources and I have the turntable connected to the PC as well. I do the least amount of AD/DA conversion possible.

If you want this as an appliance for your living room, it might not exist. Depending on your technical ability and willingness to build something yourself, a simple Windows machine that you could remote control could be a solution, but something like Volumino might also do the trick.

I run at the moment 3 different audio interfaces to do it all. 1 for the turntable, 1 for the speakers (with dedicated DACs for sub and sats) and 1 for the headphones. All are DSP corrected to achieve what I want. Oh and I have a 4th interface for the microphone, for gaming and stuff.

 

[DVDdoug]

Is it acoustically transparent to put a DSP in between a preamp output and the amp input?

No... It can be but the whole point of DSP is to change sound. (Or it can be used as a crossover.)

Turntable – currently have an old Technics unit that I use infrequently

My 40-year old dire3ct-drive Techincs still works perfectly! But to be fair, I haven't "played records" in decades. I only use it to occasionally digitize a record that's not available digitally. All of my records have been replaced or digitized so I'm sure if I'll ever use it again.

 

[fbirch]

Regarding Slide 3, this is more or less what I have, it exists, and it's called a PC.

I run DSP in the PC, I use it for to play back digital sources and I have the turntable connected to the PC as well. I do the least amount of AD/DA conversion possible.

If you want this as an appliance for your living room, it might not exist. Depending on your technical ability and willingness to build something yourself, a simple Windows machine that you could remote control could be a solution, but something like Volumino might also do the trick.

I run at the moment 3 different audio interfaces to do it all. 1 for the turntable, 1 for the speakers (with dedicated DACs for sub and sats) and 1 for the headphones. All are DSP corrected to achieve what I want. Oh and I have a 4th interface for the microphone, for gaming and stuff.

Thanks for the reply. Based on the online info I've found on the WiiM Ultra, it appears to be the living room "appliance" in slide 3. I realize a PC could be configured to perform more elaborate implementations of EQ, but what I see in the WiiM spec sheet, the ASR review of it, and other online reviews looks good, adequate to meet my needs for the near-term future. I really think that low-cost, multi-function front ends like this will have great appeal based on utility, compactness, ease of use and replaceability. As this technology progresses, they're cheap enough to replace every few years. Invest in a decent amp and good speakers and take advantage of the commoditized nature of this type of front end.

I ordered one and will play with it on my current receiver-based system before deciding whether to lock in the architecture of slide 3 and add the other pieces around it.

 

[fbirch]

No... It can be but the whole point of DSP is to change sound. (Or it can be used as a crossover.)


My 40-year old dire3ct-drive Techincs still works perfectly! But to be fair, I haven't "played records" in decades. I only use it to occasionally digitize a record that's not available digitally. All of my records have been replaced or digitized so I'm sure if I'll ever use it again.

Interesting. I've never digitized material off vinyl before. I suppose you'd get the same warm, "vinyl" sound in the digitized copy.

 

[dualazmak]

My latest system setup of PC-DSP-based multichannel multi-SP-driver multi-amplifier fully active audio rig (#931 on my project thread) would be of your interest and reference.

You may find various setup diagrams and photos of many of our ASR friends on my hosting thread "Let's share diagrams (and photos) of our total physical audio system and the whole signal path, with a few words and/or links".

 

[dualazmak]

Even if you would like to continue using passive main SP, I still recommend/encourage you to do all of XO and EQ, i.e. XO(crossover) / EQ / Group-Delay / Relative-Gain / Phase(Polarity)-Inversion (or not), etc., in upstream digital domain within PC or Mac; you can do it easily in up to 192 kHz 24 bit operation to feed the DSP-ed digital signals into your DAC unit, as I shared here showing the below signal path diagram;