[SOLVED] DAC Marketing and IMD (Also, Amps are too powerful rant)

[Vamp898]

o, that is not your hearing threshold! Hearing tests do not measure dB SPL (sound pressure level) thresholds, they measure dB HL (hearing level), which is an entirely different weighted scale designed to measure hearing levels relative to normal hearing, not relative to the threshold of hearing! 0dB HL is equal to normal hearing (technically a range of -10dBHL to 15dBHL), not 0dB SPL which is beyond normal hearing for an adult. 25dB HL is usually the threshold for clinical hearing loss (clinically diagnosed deafness), although different standards/calibrations exist in different regions.

No wonder I’m confused, if you’re using unrelated dB scales all over the place!

G

The Graph i receive after the test says dbSPL, don't complain to me^^ i am just reading it.

Why do people use equipment with pathological impedance? Just go buy something that

Most Pro Custom IEM have about that impedance, but i do not have an issue. My setup works perfect for what i want.

@gregorio is trying to tell me that my perfect solution i have no issues with is wrong^^

 

[castleofargh]

I meant digitally-controlled analog volume control, which colloquially I think most would call a digital volume control

Yup, I do that too. Here I would probably think about the confusion and specify digital control of the volume instead of digital volume, but in my head, it's digital volume for the chip changing the analog signal with high precision(and more noise at high voltage). Great against channel imbalance at low voltage.

 

[Vamp898]

Yup, I do that too. Here I would probably think about the confusion and specify digital control of the volume instead of digital volume, but in my head, it's digital volume for the chip changing the analog signal with high precision(and more noise at high voltage). Great against channel imbalance at low voltage.

I was hoping it has that and just uses the design of an traditional analog one, but no. Not just does it have the channel imbalance at very low volume, it's also hard to precisely pinpoint the volume i want.

But as it is excellent otherwise, i just set the DAC to -30db, set the amp to an comfortable listening volume and so have enough buffer in both directions if I want an higher or lower volume.

But of course, an digital volume control would have been cooler, but probably more expensive too

 

[gregorio]

The Graph i receive after the test says dbSPL, don't complain to me^^ i am just reading it.

I don’t know what to tell you. Audiograms are given in dB HL according to internationally agreed standards (ISO) and as this fact is often taken for granted some audiograms might just write dB as opposed to the full dB HL. It’s possible that instead of dB HL an audiogram might, in some regions, state a level relative to a reference dB SPL (which is what dB HL is). Obviously dB SPL is quite different to dB HL. You might want to look-up “audiogram” on Wikipedia (as well as “minimum audibility curves”).

@gregorio is trying to tell me that my perfect solution i have no issues with is wrong^^

So your “perfect solution I have no issues with” is: “Not just does it have the channel imbalance at very low volume, it's also hard to precisely pinpoint the volume i want.”? And, the very poor dynamic range indicated by your own measurements (apparently due to improper gain staging/inappropriate amp) is also your “perfect solution”?

G

 

[2leftears]

I was hoping it has that and just uses the design of an traditional analog one, but no. Not just does it have the channel imbalance at very low volume, it's also hard to precisely pinpoint the volume i want.

Well, not all analog potentiometers are of the same quality.

For ease (and accuracy) of manufacture, many logarithmic audio volume control potentiometers are manufactured with two or more partially overlapping linear resistance track sections. In practice this approximates the ideal logarithmic characteristic close enough for audio purposes. This includes some well-known premium brands.

E.g. the "15A" characteristic used in many ALPS Blue Velvet potentiometers (often found in higher grade HiFi equipment ) clearly shows the two overlapping linear regions (datasheet here, graph below on page 304). It would appear ALPS use three linear sections rather than the more commonly employed two sections, which may explain their slightly premium status and use in the better HiFi audio components.

 

[Vamp898]

I don’t know what to tell you. Audiograms are given in dB HL according to internationally agreed standards (ISO) and as this fact is often taken for granted some audiograms might just write dB as opposed to the full dB HL. It’s possible that instead of dB HL an audiogram might, in some regions, state a level relative to a reference dB SPL (which is what dB HL is). Obviously dB SPL is quite different to dB HL. You might want to look-up “audiogram” on Wikipedia (as well as “minimum audibility curves”).

I have an App to see all the values and compare them to each other to see how the hearing changed. This App says dbSPL, but the PDF says just db (does not specify if SPL or HL).

But i can change the Settings of the App from SPL to HL and the values do not change. So what was 0 dbSPL before is now 0 dbHL (there is no conversion going on).

As far as i understood, according to the ISO Standard 6.5 dbSPL equal 0 dbHL at 1kHz. According to Wikipedia, the Threshold of a young and healthy human hearing is 0db SPL at 1kHz, 1 atmosphere and 25 °C and between 2~5kHz it can go down to -9dbSPL

As i have -5db~0db at 1kHz,, i assume that it is not SPL as that would be pretty much impossible and the App that i have to review/compare the curves just doesn't know if its SPL or HL and uses SPL as default.

I did actually never care if its SPL or HL, there is a target curve and i need to be above and then im done. But i changed it to HL now as its obviously not SPL. Thanks for the clearification.

So your “perfect solution I have no issues with” is: “Not just does it have the channel imbalance at very low volume, it's also hard to precisely pinpoint the volume i want.”? And, the very poor dynamic range indicated by your own measurements (apparently due to improper gain staging/inappropriate amp) is also your “perfect solution”?

That is not my solution, whoever told you that is lying.

My solution is using the DAC for volume control and use an Volume on the Amp where both, in combination, perform excellent.

On the Amp i use
For my IEM its ~33%
For my HD 300 Pro its ~50% (that i almost never use...)
For my R70xa its 100% (these need quite some power)

All on Low Gain, of course

On the DAC i use
When listening to an concert, i am around -25 to -5db (Depends a lot on the loudness of the recording, of course)
When watching shows, i am usually around -60db to -25db (Depending on the Show, my mood, whatever)
When listening to BGM during work i am between -80db and -60db (Unless its a catchy song, then there are exceptions that go up to -15db)

Except for the R70xa, these values might change oh so slightly as i am not able to hit 33% perfectly (50% is pretty easy though as one can imagine^^)

So when i switch the Headphone/IEM, i adjust the Volume on the Amp once and then use the DAC for volume control

 

[gregorio]

I have an App to see all the values and compare them to each other to see how the hearing changed.

Huh? When you said “hearing test” I thought you meant an actual hearing test, an audiometric hearing test performed by an audiometrist, not just the output of some app! How would the app even know what SPL your IEMs are outputting at the various frequencies? And, you state the app compares values to determine how your hearing has changed, so the output it’s giving you is a delta between values, NOT a threshold!

As far as i understood, according to the ISO Standard 6.5 dbSPL equal 0 dbHL at 1kHz. According to Wikipedia, the Threshold of a young and healthy human hearing is 0db SPL at 1kHz, 1 atmosphere and 25 °C and between 2~5kHz it can go down to -9dbSPL

There are various standards, there’s also a standard where 16.5dBSPL = 0dBHL at 1kHz. Plus, it’s a curve, so the SPL changes throughout the tested spectrum. Lastly, -8dBSPL was the lowest actually recorded (if I recall correctly), which was achieved by a young child with exceptional hearing, in a top class anechoic chamber in response to a signal in the critical band. As you don’t comply with any of those conditions …

As i have -5db~0db at 1kHz,, i assume that it is not SPL as that would be pretty much impossible …

Exactly, that is what I’ve been trying to tell you! According to your description above, that figure would be the amount by which your hearing has changed, not your absolute SPL hearing threshold! And in addition, I hope you’re not using IEMs for your test.

That is not my solution, whoever told you that is lying.

That was direct quotes from your own posts (as implied by the quotation marks), so you’re effectively stating that you’re lying!

G

 

[Vamp898]

Huh? When you said “hearing test” I thought you meant an actual hearing test, an audiometric hearing test performed by an audiometrist, not just the output of some app!

Please stop reading between the lines, only read what i said and nothing more. You're doing this in every thread in this forum and did this tons of times in the past and it makes every conversation insanely cumbersome and hard to follow.

I said, i was watching the result of the hearing test in an app. Watching the result in an app != doing the test in an app.

I can watch my blood test results in an app, that does not mean i am doing blood tests with an app. I get an PDF with the result and a data file i can import into an app to show differences over time.

There are various standards, there’s also a standard where 16.5dBSPL = 0dBHL at 1kHz.

There are not various standards, there are exactly two. There is an old, outdated one from decades ago using 16.5dbSPL that no one uses anymore and a current one that everyone uses with 6.5 dbSPL

That was direct quotes from your own posts (as implied by the quotation marks), so you’re effectively stating that you’re lying!

This quote was given in a completely different context, and i already told you several times in tons of posts to stop quoting people out of context

 

[gregorio]

I said, i was watching the result of the hearing test in an app. Watching the result in an app != doing the test in an app.

Huh, you never once mentioned an app. This is what you stated:
“I am 35 now and according to the last hearing test i took which is roughly 1.5 Months ago, my hearing threshold is, depending on frequency (of course) between -5db and 5db.
As long my hearing did not heavily degrade in those 1.5 Months, i should be able to hear BGM at around 10~20db (for which i need -80~-70db on the DAC).”
And then in answer to my response “The Graph i receive after the test says dbSPL, don't complain to me^^ i am just reading it.”.

Then you stated you’re using an App to compare the results and “This App says dbSPL”, so what you’re looking at is an App, it’s the app giving you dBSPL not the audiogram?!

There are not various standards, there are exactly two. There is an old, outdated one from decades ago using 16.5dbSPL that no one uses anymore and a current one that everyone uses with 6.5 dbSPL

There are two ANSI standards, I don’t know what others there maybe. Even if the test you took were referenced to 6.5dB SPL (which certainly is not necessarily the case!) then 0dBHL = 6.5dBSPL (at 1kHz), so 0dBHL obviously cannot be 0dB SPL. You got your scales mixed up as I stated to start with and which you’ve been trying to argue against ever since!!

This quote was given in a completely different context, and i already told you several times in tons of posts to stop quoting people out of context

The context of the quotes was not clear, hence why I stated I didn’t understand what you were talking about, nevertheless they were YOUR quotes and implicitly indicated you had a least tried those uses!

G

 

[redrol]

To back up the topics talked about in this thread, I recently did a review of the Topping L70 in terms of IEM amplification only.

 

[bigshot]

You should review the IEM as to how it works with the amp. There’s nothing wrong with the amp. The IEM is wonky.

 

[Davesrose]

You should review the IEM as to how it works with the amp. There’s nothing wrong with the amp. The IEM is wonky.

Well if the topic is just heaphone amp stage: I can understand how there can be issues with IEMs and amps marketed as audiophile. So with my office setup, I like having a Benchmark DAC 1-they're now really cheap used....and there are jumper/switch settings for the level out volume as preamp for amp. Then you've got a lot of amps that try to advertise how great they are balanced. I've invariably found that means higher amplification. Where with an IEM, you'd probably be better served (and get less distortion) by having lower volume output with the DAC output stage and the unbalanced headphone stage.

 

[redrol]

You should review the IEM as to how it works with the amp. There’s nothing wrong with the amp. The IEM is wonky.

Since I didn't even talk about a certain IEM, I assume you not only didn't watch the review, you assumed I was crapping on it.

 

[bigshot]

You missed my point. You’re reviewing an am in terms of how it works with IEMs. I am saying if you’re going to do that, you should review IEMs not amps, because the IEM is the thing causing the differences in sound, not the amp. The amp should be reviewed in terms of the correct impedance transducer, whatever that is.

No, I didn’t watch it.

 

[redrol]

Whats a correct impedance transducer then smarty pants?