Izotope SRC

[elcorso]

I'll try to get my engineer friend onto this board to help clarify (he lives and breaths this stuff, including filter design), but in the meantime I can unhelpfully tell you that iZotope's max filter length adjustment varies the number of FIR filter coefficients.

 

While some (including Damien) have said that if you have the computing power, keeping the setting at the max of 2,000,000 is best. But my friend gave me a very technical (at least for me) explanation as to why this is not the case. And while my goldfish memory can not regurgitate his theory, I can tell you that it is easy to hear the adjustment, and that you are all most likely to find an ideal somewhere between 1,100,000 and 1,600,000. It is slightly interactive with where you like the Steepness. I found that the shallower the steepness, the lower I preferred the filter sample max length. For a DAC that likes a 7dB steepness, I ended up at 1,150,000. For a sigma-delta DAC that sounded best at 24dB, we ended up around 1,550,000.

 

Regarding Max filter length, what Damien copied in the A+ manual (from the iZotope manual) is:

 

Max filter length: Controls the the memory (and CPU usage) used by the resampling filter. Default value (500k) should be sufficient for most applications. Can be increased for getting vey high quality output for very high sample rates (e.g. DSD downsampling)

 

For example, I use it at maximum (2,000,000) with the Playback Designs DAC, If I up sample to the maximum, like 44.1 to 384. I like the SQ under this specific setting and situation, but have enough computer power and memory.

 

But it would be interesting to learn from your engineer friend explanations.

 

Roch

[Musicophile]

After re-reading this thread, I decided to spend some time today rather scientifically testing the effect of the various isotope SRC options in Audirvana Plus.

 

 

Following the good advice of other members of the forum, I chose a well-recorded piano title with which I was very familiar (the Zenph "re-performance" recording of "Rachmaninoff Plays Rachmaninoff"). I well-acquainted with the sound of a quality piano, having majored in music back in the antediluvian days so this was a good choice for me. I plan to re-visit these tests with other sources later on, including voice (I was a vocal performance major), string quartets, jazz piano trios, etc.

 

 

Starting with the "Pre-ringing" slider, I started at 0 / Min. Phase - after all, we don't *want* pre-ringing, do we? I observed the piano sounded a bit "dead" and muffled with this setting, so began by moving the slider all the way to the right (i.e., 1 / linear) - wow, I could really hear the pre-ringing! The piano sound got very congested, especially during complex passages - you could really hear all the ringing, but the piano *did* sound quite a bit more "live" (i.e., less muffled), so I decided to compromise (for now) on 0.5, which seemed to minimize the ringing I was hearing, while still preserving some of the treble energy I liked in the 1.0 setting.

 

 

Next, I moved to the "Cutoff freq" slider. Again, I started on the left at the lowest setting that made "sense" to me (i.e., 0.9 of Nyquist, or around 19.8kHz) - I can't see starting the rolloff much below that, though my hearing only tests up to about 17k these days In any case, I could hear a distinct lack of "sparkle" with the cutoff this low, so I moved it about as high as makes "sense" to me; i.e., about 1.10 - I know we need to filter out the ultrasonic frequencies to avoid foldback artifacts in the audible range, so can't run the cutoff frequency *too* high. I finally settled on 0.99 as my cutoff - again, a balance between the high frequency rolloff I was hearing at the lower setting vs. the artifacts I had begun to hear at the higher setting.

 

 

Finally, I worked with the steepness setting. I couldn't hear the differences as clearly here, but finally settled on 24dB - I reasoned I wanted a steeper curve, since I was starting the rolloff relatively high, at 0.99.

 

 

Finally, I listened to the new settings vs. turning off oversampling entirely. The new settings were clearly much better / clearer, with a very live but controlled sound vs. the virtually lifeless sound with no upampling. I wrote down the new settings so I could easily reproduce them later - definitely an opportunity for Damien to add SRC presets to the interface

 

 

Just to make sure I had everything set optimally, I verified my oversampling settings (I only oversample 44.1k and 48k recordings, with the reasoning that recordings originally recorded at a higher rate do not "need" oversampling), and finally glanced at the Audirvana front panel . . . and realized I had been working all along with a 24/88.2k recording, with no oversampling at all!

 

 

And now you know the rest of the story - it's very easy to fool yourself. I *very clearly* heard the changes I was expecting, though there was no change at all between any of the playback sessions

 

 

Just thought you all might like to have the opportunity for a little levity at my expense

Don't worry, you clearly weren't the only one. I've already seen many on this forum reporting differences on the Audirvana filter settings without upsampling even being active. The power of persuasion. It's a healthy lesson for all of us though not to take all of this fiddling too serious.

 

I personally stick to the standard upsampling settings, just because i'm lazy.

[Jud]

Regarding Max filter length, what Damien copied in the A+ manual (from the iZotope manual) is:

 

Max filter length: Controls the the memory (and CPU usage) used by the resampling filter. Default value (500k) should be sufficient for most applications. Can be increased for getting vey high quality output for very high sample rates (e.g. DSD downsampling)

 

For example, I use it at maximum (2,000,000) with the Playback Designs DAC, If I up sample to the maximum, like 44.1 to 384. I like the SQ under this specific setting and situation, but have enough computer power and memory.

 

But it would be interesting to learn from your engineer friend explanations.

 

Roch

 

Back near the beginning of this thread if I'm not mistaken Alexey Lukin (iZotope's developer) gave a sort of general rule of thumb that the default was fine if you were doing 2x/4x upsampling. I'm upsampling everything except DSD to 8x rates (352.8/384), and most of my music is RedBook rips, so I'm going to listen to higher values and see what that does.

[Jud]

To give context for my questions, here's what I've got for the various settings that I can recall at the moment. If there's other info needed, I'll try to recall or get it when I'm home.

 

Power of 2 Upsampling to 352.8/384 rates (the rates at which the DAC does D/A conversion, so no in-DAC oversampling)

Filter Max Length: 2,000,000 (max)

Cut-Off: 1.00 (default)

Anti-Aliasing: 200 (max)

Pre-Ringing: 0.98

 

I'm starting to work with steepness and would be happy for advice. (Default is 150.)

 

Have pre-ringing set to .98 because I want something at least close to linear phase. The dispersion characteristic of minimum phase makes things sound too muddled to me. So this means whatever ringing there is will be roughly equal before and after the original sound. I want to minimize ringing, so supposing that means steepness should be minimized. At 352.8/384 rates I probably have the luxury of making the filter very gentle. Briefly tried last night (at low volume, sleeping wife) steepness settings of 1, 2 and 3, and the world did not end. In fact I thought I heard improvement in instrumental attack and transients - going back to 150, it was like "Wait, who turned those drumsticks into limp noodles?" - though it's hard to be sure, as soft as the music was. I want to go back and do more listening tonight if I have time.

 

Are settings of 1, 2 or 3 really doing much? How about 0 - guessing that's no attenuation at all above Nyquist; is any attenuation needed with the 352.8/384 sample rates I'm using? What are the potential problems with such low settings, if any? How does the anti-aliasing setting play into all this? And finally, does anyone have the desire to make a couple of those neat graphs with the iZotope Rx demo showing, for example, the impulse response with these various settings? (I know that's being lazy; time for me to try making some of those graphs for myself when I get a chance to download and play with the demo.)

 

Thanks for any ideas/discussion/experience/impressions/wild speculation you may have.

[pl_svn]

Power of 2 Upsampling to 352.8/384 rates (the rates at which the DAC does D/A conversion, so no in-DAC oversampling)

 

Jud... does the Bifrost handle 352.8/384 input? :-0

(asking on behalf of the friend who now owns mine ;-)

[Jud]

Jud... does the Bifrost handle 352.8/384 input? :-0

(asking on behalf of the friend who now owns mine ;-)

 

Not currently, but they do seem to be releasing upgrades every so often, so perhaps at some not too distant future date.

 

Oh, and speaking of the Bifrost, this from the Bifrost FAQ on Schiit's web site:

 

How about DSD?

We will have DSD solutions for all of our DACs in the near future.

 

 

!!

[pl_svn]

Not currently, but they do seem to be releasing upgrades every so often, so perhaps at some not too distant future date.

 

... the only issue being, with Schiit, what they actually call "in the near future" :-p :-p :-p

(their "in the near future" refence DAC was supposed to be available... *last* spring/summer? :-/ )

[Jud]

... the only issue being, with Schiit, what they actually call "in the near future" :-p :-p :-p

(their "in the near future" refence DAC was supposed to be available... *last* spring/summer? :-/ )

 

Yes, though the uber analog upgrade board seemed to come out of nowhere, and the USB board upgrade became available within 6-8 weeks of when I first heard of it if I recall correctly. I think they're tending to get better at this as they gain experience, as you might expect from a small start-up.

[elcorso]

To give context for my questions, here's what I've got for the various settings that I can recall at the moment. If there's other info needed, I'll try to recall or get it when I'm home.

 

Power of 2 Upsampling to 352.8/384 rates (the rates at which the DAC does D/A conversion, so no in-DAC oversampling)

Filter Max Length: 2,000,000 (max)

Cut-Off: 1.00 (default)

Anti-Aliasing: 200 (max)

Pre-Ringing: 0.98

 

I'm starting to work with steepness and would be happy for advice. (Default is 150.)

 

Have pre-ringing set to .98 because I want something at least close to linear phase. The dispersion characteristic of minimum phase makes things sound too muddled to me. So this means whatever ringing there is will be roughly equal before and after the original sound. I want to minimize ringing, so supposing that means steepness should be minimized. At 352.8/384 rates I probably have the luxury of making the filter very gentle. Briefly tried last night (at low volume, sleeping wife) steepness settings of 1, 2 and 3, and the world did not end. In fact I thought I heard improvement in instrumental attack and transients - going back to 150, it was like "Wait, who turned those drumsticks into limp noodles?" - though it's hard to be sure, as soft as the music was. I want to go back and do more listening tonight if I have time.

 

Are settings of 1, 2 or 3 really doing much? How about 0 - guessing that's no attenuation at all above Nyquist; is any attenuation needed with the 352.8/384 sample rates I'm using? What are the potential problems with such low settings, if any? How does the anti-aliasing setting play into all this? And finally, does anyone have the desire to make a couple of those neat graphs with the iZotope Rx demo showing, for example, the impulse response with these various settings? (I know that's being lazy; time for me to try making some of those graphs for myself when I get a chance to download and play with the demo.)

 

Thanks for any ideas/discussion/experience/impressions/wild speculation you may have.

 

My settings (catch of the week):

 

Always at maximum up sampling

 

Up sampling DAC

 

Steepness: 7

Filter max length: 2,000,000

Cutoff: 1.0

Anti-aliasing: 200

Pre-ringing: 0.7 to 1.0 (recording dependent)

 

NOS DAC

 

Steepness: 7

Filter max length: 2,000,000

Cutoff: 1.0

Anti-aliasing: 200

Pre-ringing: 0.00 to 0.35 (recording dependent)

 

Roch

[Superdad]

I'm starting to work with steepness and would be happy for advice. (Default is 150.)

 

Have pre-ringing set to .98 because I want something at least close to linear phase. The dispersion characteristic of minimum phase makes things sound too muddled to me. So this means whatever ringing there is will be roughly equal before and after the original sound. I want to minimize ringing, so supposing that means steepness should be minimized. At 352.8/384 rates I probably have the luxury of making the filter very gentle. Briefly tried last night (at low volume, sleeping wife) steepness settings of 1, 2 and 3, and the world did not end. In fact I thought I heard improvement in instrumental attack and transients - going back to 150, it was like "Wait, who turned those drumsticks into limp noodles?" - though it's hard to be sure, as soft as the music was. I want to go back and do more listening tonight if I have time.

 

Are settings of 1, 2 or 3 really doing much? How about 0 - guessing that's no attenuation at all above Nyquist; is any attenuation needed with the 352.8/384 sample rates I'm using? What are the potential problems with such low settings, if any? How does the anti-aliasing setting play into all this? And finally, does anyone have the desire to make a couple of those neat graphs with the iZotope Rx demo showing, for example, the impulse response with these various settings? (I know that's being lazy; time for me to try making some of those graphs for myself when I get a chance to download and play with the demo.)

 

Thanks for any ideas/discussion/experience/impressions/wild speculation you may have. [/color]

 

Hi Jud: While I am all for you trying the extremes of the settings to hear the effect, for Steepness those are really far extremes you are playing with! 0 is essentially no filter at all--but then what happens to everything with the upsampling? But 150 is VERY steep (not sure why it is the default), and that somewhat explains why you have been preferring pre-ring up at .98. Please try experimenting with Steepness in the range from 7 to 24, maybe give .65--.8 pre-ring a shot once you have flattened the slope. I'll be surprised if you end up liking a steepness below 6, and I really think you will find nirvana in the 7-24 range I suggest.

 

After spending time with new steepness and pre-ring settings, you can also gain back some air by moving cut-off a tiny bit above 1.0, but not higher than 1.04 (which is what I settled on).

 

And once again, I encourage you to lower the filter max length--down to about 1,500,000 and see if you like that. Leave the somewhat misnomered "anti-aliasing" at 200; it is just the final attenuation floor of whatever slope you set--might as well be infinity.

 

Although I am sure you are enjoying the smooth sound by interpolating up to 352/384 into your DAC, you may have a MUCH easier time discerning the ideal for some of the settings by temporarily going to just 2X with Redbook material. Of course you will then be listening to a combination of iZotope and your DAC's DF, and thus might find slightly different ideals when you go full s/w at 352/384. Still, I think the process of familiarizing yourself with the sonic effects will be easier at 2X and will make it easier to hear each parameter's type of change when you move back to the higher rate--where some of the settings may have a more subtle effect. Though perhaps they will have MORE of an effect since you will no longer be interacting with the DAC's hardware DF. While it is hard for me to know for sure since I run an NOS 1704K DAC (176/192 USB max ability at the moment), my experience a couple weeks back with a really good sigma-delta DAC has informed much of my advice post today.

 

Anyway, keep experimenting. I know you (like many of us) enjoy having a scientific explanation of things as a guide, but each DAC is different, there are really only 4 settings, they have only mild interaction, and your ears are going to quickly guide you to what is best for you. When you get there you will KNOW it, and then you will rave about it!

When is your spouse going to go out for the evening so you can crank it up and do some proper testing/listening?! My family hates it when I play snippets of the same 6 tracks over and over during tuning sessions. But I have a soundproof room so they can't hear it!

Cheers,

ALEX

[Jud]

Hi Jud: While I am all for you trying the extremes of the settings to hear the effect, for Steepness those are really far extremes you are playing with! 0 is essentially no filter at all--but then what happens to everything with the upsampling? But 150 is VERY steep (not sure why it is the default), and that somewhat explains why you have been preferring pre-ring up at .98. Please try experimenting with Steepness in the range from 7 to 24, maybe give .65--.8 pre-ring a shot once you have flattened the slope. I'll be surprised if you end up liking a steepness below 6, and I really think you will find nirvana in the 7-24 range I suggest.

 

After spending time with new steepness and pre-ring settings, you can also gain back some air by moving cut-off a tiny bit above 1.0, but not higher than 1.04 (which is what I settled on).

 

And once again, I encourage you to lower the filter max length--down to about 1,500,000 and see if you like that. Leave the somewhat misnomered "anti-aliasing" at 200; it is just the final attenuation floor of whatever slope you set--might as well be infinity.

 

Hey, SuperD. OK, so prepare to be shocked.

 

Power of 2 Upsampling to 352.8/384

Filter Max Length: 2,000,000 (max)

Cut-Off: 1.02

Anti-Aliasing: 200 (max)

Pre-Ringing: 0.98

Steepness: 3 (and I think my preference might be for something between 2 and 3 if that were possible)

 

Although I am sure you are enjoying the smooth sound by interpolating up to 352/384 into your DAC, you may have a MUCH easier time discerning the ideal for some of the settings by temporarily going to just 2X with Redbook material. Of course you will then be listening to a combination of iZotope and your DAC's DF, and thus might find slightly different ideals when you go full s/w at 352/384. Still, I think the process of familiarizing yourself with the sonic effects will be easier at 2X and will make it easier to hear each parameter's type of change when you move back to the higher rate--where some of the settings may have a more subtle effect. Though perhaps they will have MORE of an effect since you will no longer be interacting with the DAC's hardware DF. While it is hard for me to know for sure since I run an NOS 1704K DAC (176/192 USB max ability at the moment), my experience a couple weeks back with a really good sigma-delta DAC has informed much of my advice post today.

 

I wouldn't say the 8x upsampling makes the sound "smooth." What it does is twofold: (1) Most important, it bypasses internal oversampling so the oversampling filters are left up to me. I haven't heard the oversampling filter in my DAC chip yet, and don't intend to start any time soon. (2) It pushes the sample rates high enough above audible range that I can really minimize steepness and thus ringing. The other alternative to minimize (pre-)ringing with iZotope is to move the pre-ringing slider lower. I find I don't like that, because it makes the filter dispersive (differences in time through the filter depending on frequency). It may come from my Vandersteens, or my filter preferences and the Vandersteens may both come from the same natural inclination: I love phase accuracy, especially phase consistency over frequency. Or to put it another way, I like really good accurate timing and imaging in a system.

 

In fact lowering steepness removes ringing that would otherwise mask transients in percussion, or nuances in guitar playing like plucking or strumming the strings a little harder, or harder and softer in a certain rhythm. This heightens microdynamics and drama, and contributes to an overall sense of good, tight timing. It might seem that this could diminish the opportunity to get a feeling of lushness from recordings, but to me it allows the system to bring out what is truly intended to sound lush. If everything is lush and echo-y, nothing stands out. (There are some very nice effects along these lines in The Shins' song 40 Mark Strasse from the Port of Morrow album. The lead vocal is very plain in front of you on the verses, then all of a sudden on the chorus it's got depth and is spread right across the top of the wall and ceiling.)

 

Of the two alternatives you mentioned above, for me with this DAC it's easy to discern differences in settings with the 8x rates, because as you guessed, I'm just hearing the iZotope settings unmixed with the DAC's oversampling filter.

 

Our differences re steepness and filter max length could well be effects of the max input for one DAC being at 4x rates vs. 8x rates into the other.

 

Anyway, keep experimenting. I know you (like many of us) enjoy having a scientific explanation of things as a guide, but each DAC is different, there are really only 4 settings, they have only mild interaction, and your ears are going to quickly guide you to what is best for you. When you get there you will KNOW it, and then you will rave about it!

When is your spouse going to go out for the evening so you can crank it up and do some proper testing/listening?! My family hates it when I play snippets of the same 6 tracks over and over during tuning sessions. But I have a soundproof room so they can't hear it!

Cheers,

ALEX

 

It just keeps impressing me how much the filters are the sound of a DAC, or if you like, the filters are the design of the sound and the physical parts are the execution. So an NOS DAC combined with software gives the user the opportunity to exercise a great deal of choice over his or her own sound.

[alcarp]

Hi Alex... Thank you very much for your post. I had been struggling for a long while with Izotope settings but the sound I was getting was too much on the bright side. Thanks to your post I now have them at: pre-ringing: 0.7; Cut-off: 1.02; Steepness: 24 and Filter max length: 1,550,000. A big improvement on my system - no longer sounds bright, much better balance of bass & treble and greatly improved SQ overall.

 

I have a NAD M51 DAC and am using powers of 2 up sampling.

[Superdad]

I wouldn't say the 8x upsampling makes the sound "smooth."

 

Calling it "smooth" was just lazy shorthand on my part Jud. I do understand the actual effect--and you summarized it well below:

 

What it does is twofold: (1) Most important, it bypasses internal oversampling so the oversampling filters are left up to me. I haven't heard the oversampling filter in my DAC chip yet, and don't intend to start any time soon. (2) It pushes the sample rates high enough above audible range that I can really minimize steepness and thus ringing. The other alternative to minimize (pre-)ringing with iZotope is to move the pre-ringing slider lower. I find I don't like that, because it makes the filter dispersive (differences in time through the filter depending on frequency). It may come from my Vandersteens, or my filter preferences and the Vandersteens may both come from the same natural inclination: I love phase accuracy, especially phase consistency over frequency. Or to put it another way, I like really good accurate timing and imaging in a system.

 

With a steepness of just 2-3 you are almost running filterless, so the amount of ringing (pre or post) should be very minimal at that slope, making the pre-ring setting far less critical (not that you won't have an exact preference, I just mean that each fractional change of the pre-ring slider has much greater impact the steeper the slope).

 

Being able to run 352/384 into your DAC is a huge advantage as the folded-down artifacts never make it into the audible range. So with your settings and that those high rates, it is as if you are listening to a NOS/filterless DAC--except that you are upsampling and using a very gentle filter. Nice.

 

 

In fact lowering steepness removes ringing that would otherwise mask transients in percussion, or nuances in guitar playing like plucking or strumming the strings a little harder, or harder and softer in a certain rhythm. This heightens microdynamics and drama, and contributes to an overall sense of good, tight timing. It might seem that this could diminish the opportunity to get a feeling of lushness from recordings, but to me it allows the system to bring out what is truly intended to sound lush. If everything is lush and echo-y, nothing stands out. (There are some very nice effects along these lines in The Shins' song 40 Mark Strasse from the Port of Morrow album. The lead vocal is very plain in front of you on the verses, then all of a sudden on the chorus it's got depth and is spread right across the top of the wall and ceiling.)

 

Good, tangible description. And I like that Shins album too!

 

Of the two alternatives you mentioned above, for me with this DAC it's easy to discern differences in settings with the 8x rates, because as you guessed, I'm just hearing the iZotope settings unmixed with the DAC's oversampling filter.

 

Our differences re steepness and filter max length could well be effects of the max input for one DAC being at 4x rates vs. 8x rates into the other.

 

Yes and yes--I am sure you are right. I'm just happy that you tried the other settings this week. Can't go back to that default 50 steepness now, eh? And as long as you played with the filter length and got a feel for what it brings.

 

I just need to caution others here that at Steepness of 2-3, Jud is using almost no filter. So unless your DAC sounds good with that little slope (you really would need to be running high sample rates for that to be likely), you will still want to experiment with the filter length and pre-ring settings that make the music most "real" for you.

 

 

It just keeps impressing me how much the filters are the sound of a DAC, or if you like, the filters are the design of the sound and the physical parts are the execution. So an NOS DAC combined with software gives the user the opportunity to exercise a great deal of choice over his or her own sound.

 

Well yes, except that the physical parts and design are of course still essential: Output stage, power supplies, clocking, input isolation. Get any of those wrong and the best DAC chip and filter will not bring the joy.

 

Have a great weekend!

AJC

[Superdad]

Hi Alex... Thank you very much for your post. I had been struggling for a long while with Izotope settings but the sound I was getting was too much on the bright side. Thanks to your post I now have them at: pre-ringing: 0.7; Cut-off: 1.02; Steepness: 24 and Filter max length: 1,550,000. A big improvement on my system - no longer sounds bright, much better balance of bass & treble and greatly improved SQ overall.

 

I have a NAD M51 DAC and am using powers of 2 up sampling.

 

Very glad my guideposts enabled you to find the balance that you most enjoy. After you have lived with those settings for a while, maybe try +/- small steps on the pre-ring and steepness. For pre-ring I suggest 5 hundredths to start (e.g. 0.65, 0.7, 0.75), and for steepness you can bracket a bit as you listen/repeat (e.g. 21/24, 23/24, 24/27, 24/25, etc.). But if you don't feel like you have a handle on the effect of a given parameter, then swing very wide at first to remind you of the quality that changes.

 

Many of the small changes (which ultimately affect the overall presentation and feeling) are most easily heard in initial transient attacks: percussion, piano (hardest to get "real" but you will KNOW it when you do), plucked/picked guitar, naturally recorded acoustic vocalists in harmony--oh, and I can't forget--good blatty brass horns. As much as I enjoy big, complex performances (in many genres!), I do not find those at all useful for tuning filter parameters (but they of course benefit greatly once you are done).

Assemble a 4-6 track playlist that covers these areas. Ideally these will be tracks where the first few notes have elements you intend to focus on. If you have to wade 2+ minutes into the track, then by the time you stop, make the adjustment, and find you way back to that segment, your ear may get a little lost.

 

Well, the above is just my humble method. Everyone finds what works for them and that's great.

Regards,

AJC

[Jud]

Being able to run 352/384 into your DAC is a huge advantage as the folded-down artifacts never make it into the audible range. So with your settings and that those high rates, it is as if you are listening to a NOS/filterless DAC--except that you are upsampling and using a very gentle filter. Nice.

 

I just need to caution others here that at Steepness of 2-3, Jud is using almost no filter. So unless your DAC sounds good with that little slope (you really would need to be running high sample rates for that to be likely), you will still want to experiment with the filter length and pre-ring settings that make the music most "real" for you.

 

Very much enjoy your comments. I'd like to add that unless you have an NOS DAC, or can effectively turn your DAC into one by oversampling to the rates it uses for D/A conversion (usually 352.8/384, but ESS DACs in particular sometimes use much higher rates), then I think whatever settings you use will be layered on top of your DAC's internal filters, substantially altering the resulting sound. (Please someone who knows, tell me if my impression here is incorrect.) If that's true, no matter how gentle you make your filter, ringing will be added by the internal DAC filter.

 

Good, tangible description. And I like that Shins album too!

 

 

I wanted to list some of the great music I listened to while checking out various settings, but didn't because my previous comment was already way long. But as long as you mentioned liking the Shins album, here are a few more recordings I used to evaluate:

 

Beatles Love, "While My Guitar Gently Weeps," "Strawberry Fields Forever," "Here Comes the Sun" - For folks of the generation that grew up with the Beatles, their songs are, to put it with maximal triteness, the soundtrack of our younger lives. They have an emotional resonance that few if any other songs can approach. To hear those voices with the clarity managed by George Martin and son in hi-res (24/96) can bring me to tears. With so much riding on the sound in emotional terms, it becomes really easy to tell if your system is getting things right.

 

Rosanne Cash The List, "Motherless Children" and "500 Miles" - Her dad Johnny gave her a list of what he thought were the 100 greates American songs, and she chose a dozen for this album. Great voice, lovingly presented by her producer husband. In this kind of music, bass is a plucked string instrument. If you can't hear that, ringing is muffling your transients. On the other hand, you should be able to hear the bass notes sufficiently in the mix, too (i.e., things shouldn't be wound down so tight you only hear transients and not the notes themselves).

 

Crosby, Stills and Nash Daylight Again, "You Are Alive" - Really thought this was a throwaway track when I heard it before; got the 24/192 download from HDTracks almost purely for "Southern Cross." Heard it near the end of the session when I had the settings pretty well dialed in, and it was just stunning, sounding like a whole different song. Those high harmonies are given a big soundstage to show them off. If you don't hear that, things are wound down too tight; if the locations of the individual voices start to blur into each other, it's a sign of dispersion, and your pre-ringing slider should go a bit higher.

 

Dvorak New World Symphony, "Scherzo" - Was available as a free 24/176.4 download from dCS. Great sonics, and you get to hear a lot of tympani, which is distinctive enough you will likely know if it doesn't sound right.

 

Avison Ensemble Four Seasons, "Summer" (first part, allegro con molto) - 24/192 Linn download. Very helpful in adjusting steepness and cut-off frequency. A hair too little of the former and the violins begin to sound weak, not assertive enough in the sections where they're all playing together; a hair too high on the latter and the strings sound way too harsh.

 

There were more, but I think that's enough for now.

 

Have a great weekend!

AJC

 

Many thanks, you too.

[Viola]

Hey Superdad...

 

Since the NadM51 accepts up to 192k but it upsamples everything to 844khz, should I go filterless? I am upsampling 2x to 88khz with izotope.

[Superdad]

Hey Superdad...

 

Since the NadM51 accepts up to 192k but it upsamples everything to 844khz, should I go filterless? I am upsampling 2x to 88khz with izotope.

 

Well, why not let A+/iZotope do "Power of 2" upsampling so you run at least 172.4/192 into your DAC? Then you have more control with the s/w settings and you make it easier for your DAC to get it up to its "native" rate (why is it 844 anyway?; not an even multiple of anything--unless I am being dense today).

 

But you can't actually go filterless. It's the balance between how much the s/w does and how much the h/w does. And for a 2x to 88.2, you will let nasties in with a slope below about 6.

 

Have fun and good luck!

[Superdad]

I wanted to list some of the great music I listened to while checking out various settings, but didn't because my previous comment was already way long. But as long as you mentioned liking the Shins album, here are a few more recordings I used to evaluate:

 

Thanks for the short list and comments. Good choices.

I have a feeling that if we ever got together we'd have a field day exploring each other's collections. Might be a ton of overlap, but the fun would be in discovering all the great stuff we didn't know about!

Ciao,

AJC

[alcarp]

Well, why not let A+/iZotope do "Power of 2" upsampling so you run at least 172.4/192 into your DAC? Then you have more control with the s/w settings and you make it easier for your DAC to get it up to its "native" rate (why is it 844 anyway?; not an even multiple of anything--unless I am being dense today).

 

But you can't actually go filterless. It's the balance between how much the s/w does and how much the h/w does. And for a 2x to 88.2, you will let nasties in with a slope below about 6.

 

Have fun and good luck!

 

Re the 844 kHz upsampling in the NAD M51 DAC, I don't profess to understand this but here's a quote from Hi-Fi World that may explain:

 

"An innovation NAD bring to the party is the way this DAC re-samples all material into a pulse-width-modulation signal at a sample rate of 844kHz, controlled by a clock running at 108MHz. The theory behind this is that it eliminates the jitter arising from the conversion stage, and digital ringing is eliminated."

[Superdad]

Re the 844 kHz upsampling in the NAD M51 DAC, I don't profess to understand this but here's a quote from Hi-Fi World that may explain:

 

"An innovation NAD bring to the party is the way this DAC re-samples all material into a pulse-width-modulation signal at a sample rate of 844kHz, controlled by a clock running at 108MHz. The theory behind this is that it eliminates the jitter arising from the conversion stage, and digital ringing is eliminated."

 

Well that may be a different beast then, and you may have trouble improving on it with the s/w. How does it sound with just A+, with upsampling turned off?

And does the M51's USB input support integer mode?

[Viola]

The NadM51 supports USB Integer Mode and all the features A+ provides! Since this beast basically upsamples PCM to PWM( maybe

DSD?), I was trying to figure it out what is the best S/W(software) settings would improve from non upsampling with A+ .

 

If anything below 6 steepness does introduce nasties to the audio, the the AYRE settings that Alex(izotope) describe in the begging of this thread is not a good one!

 

I will keep experimenting!

 

Thanks!

[Superdad]

Viola: If you don't upsample in A+, then the iZotope engine is not engaged and the filter settings have zero effect!

[Viola]

I know:-)

[Viola]

I will keep trying most of your advice regarding the past Nadm51 comment! I am only trying the overx2 only 88.2/96k up!

 

I'll keep you guys posted!

[elcorso]

The NadM51 supports USB Integer Mode and all the features A+ provides! Since this beast basically upsamples PCM to PWM( maybe

DSD?), I was trying to figure it out what is the best S/W(software) settings would improve from non upsampling with A+ .

 

If anything below 6 steepness does introduce nasties to the audio, the the AYRE settings that Alex(izotope) describe in the begging of this thread is not a good one!

 

I will keep experimenting!

 

Thanks!

 

As I said before iZotope settings are DAC dependent, it could very difficult that some other DAC settings would match yours for the SQ you like. Then the final user SQ is final user dependent also.

 

I found some DACs sound better (to my ears) with no up sampling, I guess it's because the internal DAC up sampling could be better to your ears/brain system. Or not up sampling at all from NOS DACs.

 

Roch