Close in jitter?

[Blumlein 88]

This is how audiophilia works...

People espouse science and objectivity, and acknowledge the existence of the 'placebo effect'. But in parallel they clearly believe that if audiophiles love vinyl, 'there must be something in it'. And so a science-based forum still finds itself discussing vinyl year after year...

If people really believed in science, vinyl would not warrant any more attention than 78s.

I agree.

It has been a bit over 20 years ago that I stopped buying vinyl or vinyl gear or RTR because it was clear CD is simply higher fidelity. In time I even divested myself of those older formats in order to simplify things, and spend money on improving the rest of my playback chain. Vinyl has been obsolete for some time. Like 8 track tape and cassette tape. Like black and white television and standard definition TV. One can be a collector or otherwise keep the format alive if one wishes. As a topic of conversation in audiophile publications or forums in regards to the current SOTA of music reproduction it should warrant no attention beyond a curiosity of what once was.

 

[Jakob1863]

This is how audiophilia works...

People espouse science and objectivity, and acknowledge the existence of the 'placebo effect'. But in parallel they clearly believe that if audiophiles love vinyl, 'there must be something in it'. And so a science-based forum still finds itself discussing vinyl year after year...

If people really believed in science, vinyl would not warrant any more attention than 78s.

The assertion in the last sentence is interesting but is that really backed up by actual data?

First of all, according to several surveys i´ve seen in the last 2 - 3 years, the number of vinylbuyers is still growing, but a proportion of 8-9% of these don´t have a turntable and a whopping fraction of ~26% (afair) does not use their turntables. No further details were given, so i don´t know if there is considerable fluctuation for these groups.

Beside those, there seems to be a proportion that prefers vinyl music reproduction - while others don´t but play vinyl nevertheless - and in contrary to your assertion above, these might _believe_ in science but might think that science didn´t examined the most relevant questions in this regard.
As said before, our hearing sense represents a nonlinear system overall and is confronted with a reproduction which is a highly distorted version of reality. Given these circumstances it is imo a valid hypothesis that a somewhat naive mechanistic evaluation approach (if anything is technically better and audible, it has to be considered as "better") might lead in the wrong direction. (means for fractions of the population)

 

[Phelonious Ponk]

There is something to vinyl. Most audiophiles are old men listening to old analog recordings that have been badly transferred to the digital medium. Vinyl's limitations often make these recordings sound"better." Of course, so does the bog-standard Ford audio system in my car. I'm not talking about compression. I have pretty highly compressed recordings that sound good. I'm talking about a lack of suppression of treble that analog took care of naturally. Nothing that a bit if eq, applied in mastering, couldn't solve.

MHO. No science to back it up. Just my ageing ears, which seem to have less tolerance for it these days. Seriously, I'm about to find a decent Bluetooth speaker for all my old classics from the 70s. I grow weary of the futile quest for fidelity in a world where we seem to care more about it than the industry producing our content.

In the meantime, I've recently acquired a '43 Gibson LG2 that looks like it spent its 74 years tied to the back of a hobo, lovingly pieced back together, brought back to impeccable fidelity. They just don't make 'me like they used to.

Tim

 

[DonH56]

The imaginary component of the complex numbers show the phase which we don't care about. What is shown is just the "real" component which represents the amplitude of the basis function. We don't need to maintain the phase because we don't need to invert back to time domain.

Hmmm... While admitting I have not followed too closely lately (work and Life issues), I rarely use just real or imaginary data alone unless looking for a reactive component. The magnitude reported in an FFT is normally the RSS of real and imaginary data. The magnitude of a complex number is not accurately given by just the real (or imaginary) component; the magnitude is affected by each. I must have missed something crucial...

 

[DonH56]

There is something to vinyl. Most audiophiles are old men listening to old analog recordings that have been badly transferred to the digital medium. <elided>

I have long espoused the theory that the main reason vinyl sounds better, other the usual technical details like channel coupling, is that so many CDs have been remade so poorly. I put my vinyl rig away long ago and have no real desire to set it up again (even if I had space), but before and since have done many, many vinyl-to-CD comparisons. Sighted and long switching times, yes, but the differences are glaringly obvious. Most of the "pop" CDs I own sound very different than the LP versions and not in a good way. The CDs I have that exhibit good fidelity (to me) make clear just how good the medium can be. Too many CDs sound like they were transferred using a high-speed dubber, compressed and EQ'd hot, then dumped on the masses. I believe many CD mixes/remasters would sound just as bad if cut to new LPs.

IMO! - Don

 

[SoundAndMotion]

The imaginary component of the complex numbers show the phase which we don't care about. What is shown is just the "real" component which represents the amplitude of the basis function. We don't need to maintain the phase because we don't need to invert back to time domain.

Hmmm... While admitting I have not followed too closely lately (work and Life issues), I rarely use just real or imaginary data alone unless looking for a reactive component. The magnitude reported in an FFT is normally the RSS of real and imaginary data. The magnitude of a complex number is not accurately given by just the real (or imaginary) component; the magnitude is affected by each. I must have missed something crucial...

No, I don't think you missed anything.
Magnitude = sqrt(re(FFT)^2 + im(FFT)^2) = sqrt(FFT * conj(FFT))
Phase = arctan(im(FFT)/re(FFT))

 

[RayDunzl]

All this arguing over jitter got me all jittery.

12kHz tone at 48kHz sample rate

Top: In-room via speakers and captured via UMIK-1
Bottom: Preamp to PC on-board ADC via 25 foot cheap cable

I wonder if it is the speakers or the amplifier or the UMIK-1 adding the noise...

The noise on the in-room measurement starts to rise out of the noise floor at about -40dB signal.

 

[RayDunzl]

I wonder if it is the speakers or the amplifier or the UMIK-1 adding the noise...

Hmm...

Maybe speakers...

The above was with Krell/MartinLogan

Here is the JBL LSR 308

 

[Jakob1863]

DonH56 and SoundAndMotion are correct.
Imagine the complex plane and you´ll see........

 

[RayDunzl]

Based on the Technical exposition above...

While I purportedly have a rather jitter-resistant DAC, it would seem to me that the power amplifier/speaker combo contributes far more "trouble" here than can be seen coming from all the jitter-contributing stuff in my audio chain:

PC ->REW Generator -> Optical Out at PC -> 25 foot Optical Cable -> Optical/Coax Switch -> Behringer DEQ2496 -> MiniDSP OpenDRC-DI with FIR filter active -> Benchmark DAC2 HGC -> Krell KTC preamp -> [Krell FPB 350 mcx -> Martin Logan reQuest] or -> [JBL LSR 308 with internal power amps and some sort of ADC to feed them].

 

[RayDunzl]

Is there a proper J-Test audio file available for download somewhere? I'd like to run one here and measure, I don't think I can make one (easily).

 

[amirm]

Ah, you are both right guys. I could say it is a sign of getting old but sometimes you just post something stupid. My high-school math teacher would have flunked me for that.

And Don, you need to get meaner with me when I am wrong. You are so gentle in your approach.

 

[Thomas savage]

Ah, you are both right guys. I could say it is a sign of getting old but sometimes you just post something stupid. My high-school math teacher would have flunked me for that.

And Don, you need to get meaner with me when I am wrong. You are so gentle in your approach.

Just can't shake the Microsoft out of you can we....

 

[amirm]

Just can't shake the Microsoft out of you can we....

Yeh I thought about putting out a service pack out to fix my error.

 

[Fitzcaraldo215]

All this arguing over jitter got me all jittery.

12kHz tone at 48kHz sample rate

Top: In-room
Bottom: Preamp to PC on-board ADC via 25 foot cheap cable

View attachment 6936

I wonder if it is the speakers or the amplifier or the UMIK-1 adding the noise...

The noise on the in-room measurement starts to rise out of the noise floor at about -40dB signal.

Is there a proper J-Test audio file available for download somewhere? I'd like to run one here and measure, I don't think I can make one (easily).

Ray - I think your measurements are interesting, but, correct me if I am wrong, they are not related to jitter measurements. Those are done with two simultaneous tones, I believe, sort of like IM distortion measurements.

But, it is an interesting question of what is causing those almost symmetrical side bands inroom. It looks a bit like a jitter spectrum, but I doubt that it is.

 

[The Smokester]

This is how audiophilia works...

People espouse science and objectivity, and acknowledge the existence of the 'placebo effect'. But in parallel they clearly believe that if audiophiles love vinyl, 'there must be something in it'. And so a science-based forum still finds itself discussing vinyl year after year...

If people really believed in science, vinyl would not warrant any more attention than 78s.

Tell me: How do you learn?

 

[RayDunzl]

Ray - I think your measurements are interesting, but, correct me if I am wrong, they are not related to jitter measurements.

I see a lack of jitter effects in the preamp output, but something nasty intrudes on the speaker output in the case of both sets of speakers.

Wouldn't (at least severe) jitter problems show up in a steady tone - as in at the preamp output? It takes the same path as what goes on to the speakers. That's my baseline. No jitter detectable with my crude measurement devices.

Since none is noted, the speaker output should be just as clean, but, of course, it isn't, for whatever reasons.

Amir has been arguing elsewhere that measurements should be taken at the DAC output, and that clock measurements are nice, but not what we listen to.

So, here, I don't listen to DAC output, but can crudely measure it, but I do listen to speaker output, so I look there to compare.

My point being that what comes out of the speakers is already distorted enough already to make too much concern about jitter (at least here) seem moot.

So, I'll stop being all jittery, and continue to quietly observe the rest of the thread.

Carry on!

 

[RayDunzl]

But, it is an interesting question of what is causing those almost symmetrical side bands inroom.

I hadn't thought about that too hard, but, yeah...

For the MartinLogans the path after the preamp is all analog, for the JBL, I suppose there's a re-digitization before the Class-D amps.

Maybe it's an artifact of the microphone and its ADC. It doesn't show up on the preamp output, so it isn't a problem at the PC or at REW.

We need somebody else to output a 12kHz tone and show their 90dB speaker output capture not using a USB mic.

JBL
(reddish) vs MartinLogan (bluish)

 

[Fitzcaraldo215]

I see a lack of jitter effects in the preamp output, but something nasty intrudes on the speaker output in the case of both sets of speakers.

Wouldn't (at least severe) jitter problems show up in a steady tone - as in at the preamp output? It takes the same path as what goes on to the speakers. That's my baseline. No jitter detectable with my crude measurement devices.

Since none is noted, the speaker output should be just as clean, but, of course, it isn't, for whatever reasons.

Amir has been arguing elsewhere that measurements should be taken at the DAC output, and that clock measurements are nice, but not what we listen to.

So, here, I don't listen to DAC output, but can crudely measure it, but I do listen to speaker output, so I look there to compare.

My point being that what comes out of the speakers is already distorted enough already to make too much concern about jitter (at least here) seem moot.

So, I'll stop being all jittery, and continue to quietly observe the rest of the thread.

Carry on!

Yup, unless you are using some piece of Schiit or similar for your DAC, I think the consensus here is jitter does not matter bigly with competent DACs, especially not compared to what comes out of the speakers into the room.

Nontheless, even if not jitter, it would be interesting to know the cause of the symmetrical side bands in your measurements. I know the inroom traces are with a mike picking up the amplified signal out of the speakers. But, I am not clear on the other measurement. Is that the signal coming from the DAC before going through preamp,amp and speakers?

 

[Blumlein 88]

Is there a proper J-Test audio file available for download somewhere? I'd like to run one here and measure, I don't think I can make one (easily).

I can send you copies when I get back home later Ray.