XSP-1 VS. NAD C658?

[geeqner]

As my search for a new Pre-Amp continues - one relatively new unit has intrigued me.

My current "front-runner" of choice is the Emotiva XSP-1

But some relatively recent reading has also led me to consider the NAD C658 Unit.

The C658 is a relatively new unit - it has probably been on the market for about 6 months, but the MAIN feature that makes it potentially attractive (DIRAC) had only recently been implemented / available.
(Plus, surprisingly, there has seemed to be a lack of "buzz" about it - maybe the buzz-mongers have been waiting to review it with DIRAC capability?...)

The only other thing that makes me a tad leery of the C658 is that it does ALL of the pre-amp / source selection functions in the DIGITAL domain. I TRY to not be an "Analog Snob" but unless the DSP and D-to-A and A-to-D is really "cutting edge", I worry that the sound quality will suffer and whether it will really be an "upgrade" from what I am using now (or not)? It SUPPOSEDLY shares a lot of the tech used within the Masters M10/M12 products, but to WHAT degree?. It would have been "cool" to see an "Analog Bypass" mode built into the C658.


I guess that in light of considering DIRAC - perhaps a second-hand XMC-1 or RMC as If I have heard correctly, one or both of these already support it?


[My NAD 7225PE Receiver that is presently serving "Pre-Amp" duty was a nice, solid little unit - but it is probably past it’s prime and I believe it to be the Weak Link in my current system (but I could be wrong)...]



But then again, in my less-than-optimal listening room (Living Room) the benefits of Dirac and fresh (NEW) electronics may outweigh any penalty incurred.

[Other Pre-Amp options currently being mulled-over include the PS Audio Stellar Gain Cell / DACT, or perhaps a gently-used 2-channel HIGH-End Pre if I can get a good deal on one.  If I go with the NAD, I could probably offset part of its cost by selling my Node 2i as this feature is "built-in" to the C658.]
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[mountain]

The AVS forum currently has 844 posts on this preamp, dac, streamer.  Activity has picked up since Dirac has been implemented on this unit.  Good shopping.

[KeithL]

Dirac Room Correction is a digital process.... so, if you want to use Dirac, then your audio signal MUST be converted into digital in order to do so.

Of course, with a unit like the XMC-1, if your input is analog, there is the option of not using Dirac, and so not doing any conversion.

So, as long as you're running Dirac, then there WILL be a conversion to digital - and the only question is of the audio quality with which the conversion is carried out.

(Since the architecture on the NAD is designed as "pure digital" it would require significant changes to offer an analog bypass.)

And, yes, the XMC-1 does sound really nice, both in pure analog, and in digital modes.

(I haven't heard the NAD unit, but I very much doubt that it sounds better than an XMC-1...)

At this moment the Dirac code for the RMC-1, which will be the new version, is still being finalized.

However, the XMC-1 uses the original version of Dirac Live for Emotiva, which is still currently available.

If you purchase a used XMC-1 from someone, you will technically not be able to transfer their free Dirac LE license to yourself, because the license is not transferable.

However, you will be able to purchase a license of your own for the full (original) version....

(And, if they were to give you their user name and password for the version they got with the XMC-1, it would work, and we wouldn't know... )

Aug 29, 2019 9:26:50 GMT -5 geeqner said:

As my search for a new Pre-Amp continues - one relatively new unit has intrigued me.

My current "front-runner" of choice is the Emotiva XSP-1

But some relatively recent reading has also led me to consider the NAD C658 Unit.

The C658 is a relatively new unit - it has probably been on the market for about 6 months, but the MAIN feature that makes it potentially attractive (DIRAC) had only recently been implemented / available.
(Plus, surprisingly, there has seemed to be a lack of "buzz" about it - maybe the buzz-mongers have been waiting to review it with DIRAC capability?...)

The only other thing that makes me a tad leery of the C658 is that it does ALL of the pre-amp / source selection functions in the DIGITAL domain. I TRY to not be an "Analog Snob" but unless the DSP and D-to-A and A-to-D is really "cutting edge", I worry that the sound quality will suffer and whether it will really be an "upgrade" from what I am using now (or not)? It SUPPOSEDLY shares a lot of the tech used within the Masters M10/M12 products, but to WHAT degree?. It would have been "cool" to see an "Analog Bypass" mode built into the C658.


I guess that in light of considering DIRAC - perhaps a second-hand XMC-1 or RMC as If I have heard correctly, one or both of these already support it?


[My NAD 7225PE Receiver that is presently serving "Pre-Amp" duty was a nice, solid little unit - but it is probably past it’s prime and I believe it to be the Weak Link in my current system (but I could be wrong)...]



But then again, in my less-than-optimal listening room (Living Room) the benefits of Dirac and fresh (NEW) electronics may outweigh any penalty incurred.

[Other Pre-Amp options currently being mulled-over include the PS Audio Stellar Gain Cell / DACT, or perhaps a gently-used 2-channel HIGH-End Pre if I can get a good deal on one.  If I go with the NAD, I could probably offset part of its cost by selling my Node 2i as this feature is "built-in" to the C658.]
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[creimes]

Seems as though guys are picking up the XMC-1 trade ins from Emotiva for $1450, great unit at that price, excellent analog performance and Dirac as you know, I'll go check out the NAD unit you are looking at, I'm curious of the price

Chad

[geeqner]

The NAC C658 is a dedicated 2-CHANNEL Unit (or 2.1 - it has Sub Output) and includes a built-in BlueSound Module for around $1600 new

They have a free "light" version of Dirac that handles 2-channel Audio Frequencies.
For an additional $100 license - you can get the "full version" that does a better job of handling the full audio spectrum / more complex scenarios.
THEIR version of Dirac is supposed to (soon) include management of the Sub down to sub-50Hz frequencies

As my 2-channel system does not double as HT (my speakers are in the N-S corners of the room, and the TV in there is at the S. End and would require E-W speakers) I am primarily interested in 2.1 channel operation.   Due to WAF issues - the Sub more-or-less HAS to live in the NW Corner of the room.  So my concern would be comparing how a Dirac-based solution would work in a less-than-optimal Living Room vs. the XSP-1 which is pure Analog, but also has some adjustable filters / cross-over management.

My understanding is that Dirac help to adjust for TIMING / phasing anomalies as well as the Frequency stuff that the XSP-1 could also do. But how much of a trade-off is the benefit of Dirac vs. the "Pure Analog" prowess and LOW noise floor of the XSP-1 if they were both utilized in my Living Room? (If I could arrange it, it would make for an interesting "shoot-out"...)

From a COST standpoint - ALL (3) of these possibilities [Emo XSP-1 / Used Emo XMC-1 / NAD C658] are within roughly the same budget range.

• BOTH of the Emotiva units mentioned here are within "spitting distance" price-wise
• The NAD unit lists for a bit more, but I could sell my BlueSound Node 2i to recover most of the difference, since that is built-into the C658

[creimes]

You could add a MiniDSP DDRC-24 and UMIK-1 to the XSP-1 but it would add $474 to the price tag which at that point the XMC-1 or NAD unit would make more sense, the only bonus of the MiniDSP unit is 4 presets of Dirac.

www.minidsp.com/products/dirac-series/ddrc-24

[KeithL]

I am personally a firm believer in the capabilities of digital technology.

Which is a nice way of saying that I am convinced that a digital device can sound as good as a purely analog one... however, in reality, many do not.

To my ears, the XMC-1 in pure analog mode (Reference Stereo), sounds as good as the XSP-1.... and pretty darn close in its digital mode if you disable all the processing.

The XSP-1 has Tone trims (tone controls with limited range) and bass management (which means that you get to choose the frequency at which you cross over between your main speakers and your sub or subs.)

The XMC-1 has multi-band parametric equalizers that can be used to manually adjust each channel, individually, with great precision, and in great detail (and so do the XMC-2 / RMC-1 / RMC-1L).

These are implemented digitally - which means that they deliver "theoretically perfect performance".

Purely analog parametric equalizers do exist, but they are incredibly complex and expensive, and so aren't found in home audio equipment.

(Also, because they are so complex, and involve so many parts and circuit paths, they virtually all introduce at least some coloration or distortion.)

To use a manual parametric equalizer, you basically play some test tones, make a bunch of measurements, and manually make the settings necessary to do what you want.

In general, you graph the results of your measurements, compare those to what you would like, and then figure out what you need to adjust to get what you want.

This involves making some decisions, deciding what response curve you really want, deciding which errors and differences to correct, then making the proper adjustments.

It also tends to be far more complex than it sounds from that brief description.

(There are up to 11 PEQ bands for each speaker in each of the two manual Speaker Presets... each of which has three parameters you can set.)

What Dirac basically does is to play some test tones, take a bunch of measurements, compare the result of those measurements to the "target curve" you've chosen, then calculate the corrections necessary.

These corrections are then output in the form of a set of filter parameters - which are then downloaded to the XMC-1 and used to configure its "Dirac Room Correction engine".

Dirac's calculations include the details necessary to correct the same flaws as a manual parametric equalizer (frequency response issues) plus time domain issues (like impulse response).

(The LE version has a preset target curve that defines "a room that sounds flat"..... the FULL version allows you to customize your own target curves.)

 

How valuable this is to you will depend on your speakers, your room, and the rest of your system.

If you had perfect speakers, and a perfect room, then both manual PEQ settings and Dirac Live would be totally unnecessary.

And, to be honest, if your system, or your room, were absolutely awful, then neither would help very much.

However, in many typical situations, proper room correction can make a huge difference....

And, in those situations, Dirac often does an impressive job of improving how everything sounds....

(And, even in many situations where you could make the same corrections manually, Dirac does a job that's equally good or better, much more quickly, and with a lot less work.)

Aug 29, 2019 11:02:42 GMT -5 geeqner said:

The NAC C658 is a dedicated 2-CHANNEL Unit (or 2.1 - it has Sub Output) and includes a built-in BlueSound Module for around $1600 new

They have a free "light" version of Dirac that handles 2-channel Audio Frequencies.
For an additional $100 license - you can get the "full version" that does a better job of handling the full audio spectrum / more complex scenarios.
THEIR version of Dirac is supposed to (soon) include management of the Sub down to sub-50Hz frequencies

As my 2-channel system does not double as HT (my speakers are in the N-S corners of the room, and the TV in there is at the S. End and would require E-W speakers) I am primarily interested in 2.1 channel operation.   Due to WAF issues - the Sub more-or-less HAS to live in the NW Corner of the room.  So my concern would be comparing how a Dirac-based solution would work in a less-than-optimal Living Room vs. the XSP-1 which is pure Analog, but also has some adjustable filters / cross-over management.

My understanding is that Dirac help to adjust for TIMING / phasing anomalies as well as the Frequency stuff that the XSP-1 could also do. But how much of a trade-off is the benefit of Dirac vs. the "Pure Analog" prowess and LOW noise floor of the XSP-1 if they were both utilized in my Living Room? (If I could arrange it, it would make for an interesting "shoot-out"...)

[geeqner]

Thanks for the crash-course education on that, Keith:

I DO know how Parametric Equalizers typically work. I also know that most "audiophiles" traditionally eschew the idea of using equalizers. OTOH, many "Pro" Audio installations often use 2 or more equalizers - one that is usually used to compensate for acoustics of the venue and LEFT THAT WAY / "locked-down", with one or more SEPARATE units that are used to tailor the material being presented / compensate for variables in the Source material. (My personal tastes fall somewhere in the middle - If anything is going to be used to compensate for acoustics, etc, - it had BETTER offer far more benefit than the potential distortion that it could introduce, and modern DSP, if "done right" definitely holds the promise of pulling this magic trick off...)

As I have been limiting my choices to 2-Channel, and really do not have the space / proper room for Home Theater - the thought of using a piece geared towards HT never really entered my mind and I had not done any buyer's-research in that area.

If I were to attempt to re-locate my speakers to asymmetrically flank the TV and re-configure the TV speakers to act as a center channel (or add a 1-channel amp / "blade" to my XPS-2 and a Center Speaker), I MIGHT be able to pull-off BOTH a good 2.1 channel Stereo system and a serviceable 3.1 HT setup. I might have to give more thought to a re-furbed XMC-1...

[KeithL]

I personally just run 2.1 in my living room as well... and I've experimented with a discrete center channel.

I find that the value of having a center channel is going to depend largely on both your room and your seating arrangements.

I find that two speakers work just fine because I have a more or less symmetrical room and tend to sit more or less in the center.

And, when you're sitting directly between the speakers, the phantom center image works perfectly well for me.

(I hear very little difference if I add a physical center speaker.)

Where you see the benefit of a center channel is if you don't always sit in the center - or if you tend to have guests seated at various spots around the room.

If you only have two speakers, and you move closer to one or the other, dialog and other sounds that should be centered will tend to "pull" towards the closer speaker.

This will tend to exaggerate the fact that you are sitting off-center.

Whereas, if you have a separate center channel speaker, those sounds originate from it, and so tend to be pulled towards the center (where they belong).

So, in that situation, a real center speaker delivers a more concise sound stage.

I would say that most modern DSPs are capable of delivering close to "theoretically perfect" performance when implementing functions like filters.

The biggest question is how much quality you sacrifice at the points where the audio signal is first converted from analog to digital - and then converted from digital back to analog.

Aug 29, 2019 12:24:07 GMT -5 geeqner said:

Thanks for the crash-course education on that, Keith:

I DO know how Parametric Equalizers typically work. I also know that most "audiophiles" traditionally eschew the idea of using equalizers. OTOH, many "Pro" Audio installations often use 2 or more equalizers - one that is usually used to compensate for acoustics of the venue and LEFT THAT WAY / "locked-down", with one or more SEPARATE units that are used to tailor the material being presented / compensate for variables in the Source material. (My personal tastes fall somewhere in the middle - If anything is going to be used to compensate for acoustics, etc, - it had BETTER offer far more benefit than the potential distortion that it could introduce, and modern DSP, if "done right" definitely holds the promise of pulling this magic trick off...)

As I have been limiting my choices to 2-Channel, and really do not have the space / proper room for Home Theater - the thought of using a piece geared towards HT never really entered my mind and I had not done any buyer's-research in that area.

If I were to attempt to re-locate my speakers to asymmetrically flank the TV and re-configure the TV speakers to act as a center channel (or add a 1-channel amp / "blade" to my XPS-2 and a Center Speaker), I MIGHT be able to pull-off BOTH a good 2.1 channel Stereo system and a serviceable 3.1 HT setup. I might have to give more thought to a re-furbed XMC-1...

[geeqner]

Yeah -

My LR works great as a Semi-Formal LR until you start adding "tech" into it.

We refuse to make the TV the "Focal Point" of the room - that is the role of the Fireplace.  So:
Instead of putting the TV over the FP (add-in no access for wiring)



At present, Stereo Speakers are at NW & SW Corners of room with Sub between W. End of Loveseat and wall
(Maybe Dirac IS "the answer"...   )