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SMSL SU-9 Balanced DAC Review

Veri

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Can someone address this Reddit post on this subject.. is this guy right? I’m not an EE and honestly don’t know. This person claims anything besides brick wall is wrong wrong wrong.
He conveniently forgets minimum phase filters are used in minimum latency applications like for stage or other real time effect usage. Never heard anyone complain... I don't see the issue, attenuation strength and filtering out ultrasonics is more important than perfect phase (which most people won't hear either way but for the most 'golden' ears).
 

Dougey_Jones

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I’ve read studies from multiple sources regarding the psychological “benefit” of ultrasonics and their affect on the perceived enjoyment of music. Obviously artificial ringing won’t be enjoyable, but is there a filter that will limit ringing but still allow information say from 20-30khz to make it through?
 

BDWoody

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I’ve read studies from multiple sources regarding the psychological “benefit” of ultrasonics and their affect on the perceived enjoyment of music.

Got a link for any of those studies?

Hard to imagine the mechanism for a benefit from what we are physically unable to perceive.
 

Dougey_Jones

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Got a link for any of those studies?

Hard to imagine the mechanism for a benefit from what we are physically unable to perceive.

Thats kind of a weird way of thinking about it, just because you can’t “see” certain light spectrums doesn’t mean they don’t affect you by burning your skin or causing cancer lol. Just because we can’t “hear” a 10hz tone at high volume doesn’t mean it won’t vibrate your whole body and your walls..

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0095464

https://www.frontiersin.org/articles/10.3389/fpsyg.2017.00093/full

https://www.researchgate.net/public...uency_Sounds_Affect_Brain_Activity_Hypersonic
 

bennetng

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Can someone address this Reddit post on this subject.. is this guy right? I’m not an EE and honestly don’t know. This person claims anything besides brick wall is wrong wrong wrong.
Basically except the newer Sabres offer this "Brickwall" filter, the older Sabres and other chip makers including AKM, Cirrus Logic and TI don't have a single filter works like the "Brickwall" one, they all go through fs/2 to a certain extent. However going through fs/2 or not is not the only parameter to judge a filter, stopband attenuation strengh, passband ripple, latency, intersample over are also other valid concerns.
https://www.audiosciencereview.com/...u-m4-audio-interface-review.15757/post-533042
https://www.audiosciencereview.com/...le-peak-greater-than-6-dbfs.14095/post-447422
https://www.audiosciencereview.com/...e-10t-welcome-to-add-others.16332/post-533137
No, "Brickwall" vs "Linear phase fast" is neither "right" or "wrong", it is just a matter of trade off. For example, you get full attenuation at fs/2, but 20dB poorer attenuation depth and stronger passband ripples. If you ask me "is it audible?", I can also ask if some minor imaging up to 0.55fs is audible or not.
 

Dougey_Jones

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I don’t really understand what most of that means unfortunately
 

gvl

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Does ESS brickwall maintains phase for all frequencies? Given its group delay matches other linear phase filters, it would seem it's a linear phase as well?
 

Dougey_Jones

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Dougey_Jones

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So where does that leave us?
 

gvl

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So where does that leave us?

In terms of which is the best filter? Brickwall or Fast Linear are closest to the best theoretical filter as they don't change the phase and provide good suppression of ultrasonic content. Pre-ringing is not really an issue, so there is little reason to use miminum phase or slow filters in this application, or the hybrid one for that matter. And slow filters will allow some utrasonics through which while inaudible themselves can cause in artifacts in the audible range.
 

tortoise

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Hi everyone! This is my first post ever. Love this forum, though I often don't understand the technical terms.

I just ordered the SU-9 and it should be here in a few days. I've had a couple Schiit DACs and neither of them had a volume control. So I never really worried about that.

With the SU-9, should I just leave it on fixed volume or should I have it on variable then be able to change the volume? I'm assuming that it goes to 99 if it's fixed.

I will pair it with the the Monolith THX 887 that I just got today and I already love it (using it with the Modi 3 at the moment, but will run everything balanced once I get the SU-9). Ideally, I'd like to keep it simple and change the volume on the amp, but would that hurt overall performance if the volume on the SU-9 is always the same?

I apologize if it's a stupid question but I tried googling this and I never quite got a clear answer.
 

Dougey_Jones

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Not a stupid question.

If it’s the same as my SU-8 v2, then “fixed” is just “Max” volume, which is actually 38.. I run mine balanced into a Classe CAP-151 integrated with great results. Volume control and balance is controlled by the integrated.
 

bennetng

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In terms of which is the best filter? Brickwall or Fast Linear are closest to the best theoretical filter as they don't change the phase and provide good suppression of ultrasonic content. Pre-ringing is not really an issue, so there is little reason to use miminum phase or slow filters in this application, or the hybrid one for that matter. And slow filters will allow some utrasonics through which while inaudible themselves can cause in artifacts in the audible range.
Also the use of the word "apodized". It is just "windowing" in a generic sense. Consider the use of unapodized filter of a certain length (127):
dirchlet.png


Now add a window to apodize it:
hamming.png


Another window:
BlackmanNuttall.png


Without windowing, a very long filter is required to achieve comparable passband ripple and stopband attenuation, similar to what Chord does, impractical and inconvenient.
2047.png

index.php
 

Dougey_Jones

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Sometimes this place is too technical for me
 

Dougey_Jones

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Keep reading, researching and pushing your own technical knowledge forward. For every hour I spend here. I spend two trying to figure it out!
I'm still in the very flat part of the learning curve.

Oh I know, I just meant that I’m still trying to wrap my head around the specific trade offs between “Fast Linear” and “Brickwall” where modern Sabre chips are concerned.

We need a detailed decision tree to make this easier!
 

gvl

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I’m still trying to wrap my head around the specific trade offs between “Fast Linear” and “Brickwall” where modern Sabre chips are concerned.

Think of it as a different EQ that kills the side effects of DA conversion in a region you can't hear. And don't over think it, either is fine for your purposes, and the rest of the filters too for that matter. Thankfully there's no NOS mode.
 
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