[racebit]

You have a wrong understanding of bit perfection. The term stands for the lack of resampling, but of course any form of digital signal processing is allowed and represents no signal degradation per se – quite the opposite, if you think of an over-all linearization of a system (primarily adapted to the sound transducers' nonlinearities). Every recording you listen to has been equalized once or twice. And the filters you are expecting from your Chord DAC are digital equalizers as well. Crossfeed and digital volume control represent DSP and therefore also violate your image of «bit perfection». The M Scaler destroys bit perfection, too. So please forget it and use the proposed equalizer! Like me.

Thank you for your reply. it will be great if you are right
My idea was that operations done inside DAC or Mscaler are done by Rob and he knows the best way to do it to minimize loosing the underlying information he is trying to reconstruct, whereas operations implemented by other people would not have the care to not destroy that information, as it is usually not used. Regarding operations done during recording (including the Dolby, frequently mentioned by Rob), I was assuming what is lost is lost, nothing can be done about it, and the idea was to avoid loosing any thing more.
But again, if you are right my problems are solved. Thanks for the help.
Can you please please tell me what EQ module are you using with foobar2000?

 

[JaZZ]

Thank you for your reply. it will be great if you are right
My idea was that operations done inside DAC or Mscaler are done by Rob and he knows the best way to do it to minimize loosing the underlying information he is trying to reconstruct, whereas operations implemented by other people would not have the care to not destroy that information, as it is usually not used. Regarding operations done before/during recording (including the Dolby, frequently mentioned by Rob), I was assuming what is lost is lost, nothing can be done about it, and the idea was to avoid loosing any thing more.
But again if you are right, my problems are solved. Thanks for the help.
Can you please please tell me what EQ module are you using with foobar2000?

There's a link in my post before my previous post.

We're not talking of Dolby and the like, which is entirely analogue (therefore extremely compomized), but digital signal manipulations, which are done on every single recording you have ever listened to (otherwise it would be bad luck, say if you have some direct-DSD recordings that are true direct-DSD). So you can't differentiate between good and bad DSP, you have to live with what you get, the same as with good and bad recordings generally. Fortunately it will be extremly hard (impossible?) to design an equalizer that degrades the signal by itself – they're all based on unambiguous mathematical functions.

Think about it: The signal from a microphone destroys «bit perfection» of an ADC in a recording studio, which would process just zeroes without an external signal causing these arbitrary modifications on the previously pure sample values.

 

[Ragnar-BY]

Well, we are consumers, so for us recorded and mastered track is a starting point. Otherwise we can discuss this for ages.

EQ may change phase and phase means time. WTA filters are all about correct time perception, so equalizer potentially could make things worse. In my opinion EQ should be used only when absolutely necessary, so I don`t use it for headphones at all.

Anyway, I hope Rob will share his thoughts about software equalization during playback.

 

[x RELIC x]

It's always a matter of compromise if the headphone really isn't tuned to one's liking and one feels they need to compensate extensively. One can add an analogue tone control like the Schiit Loki, add a warm amp, or one could use EQ. Personally I'd use EQ as it's less destructive in the digital domain (still technically destructive though).

I'm of the same mindset as Rob... as in, if you are trying to 'fix' the tonal balance of your headphones then it's time to get different headphones.

You do not need a lot of power for 300 ohm headphones. The HD800S will give 90dB SPL at 0.22v RMS; this means you will get 116 dB SPL from Hugo using HD800S; that is levels that will cause long term hearing loss, so yes it's plenty.

Unless the 'phones are crazily insensitive, I would not use an external amp - you will only lose transparency. Much of the supposed benefits of external amps is that it offers more distortion - and 2nd harmonic distortion thickens up the sound, making it sound phat with a bigger bass. Now if you prefer that then I won't argue - one's taste is personal. But it is not accurate.

I agree with Jazz - if you have 'phones that are too bright simply use some EQ. Better still is to purchase warmer headphones, such as the AQ nighthawks.

Rob

 

[JaZZ]

Well, we are consumers, so for us recorded and mastered track is a starting point. Otherwise we can discuss this for ages.

EQ may change phase and phase means time. WTA filters are all about correct time perception, so equalizer potentially could make things worse. In my opinion EQ should be used only when absolutely necessary, so I don`t use it for headphones at all.

Anyway, I hope Rob will share his thoughts about software equalization during playback.

In fact every uneven frequency response comes with a correspondingly uneven phase response. So equalizing is able to correct both amplitude and phase response at once (search for «filter theory») – of course just within the limits of the achievable accuracy. That's often misunderstood. Provided that you don't make the (over-all) curve worse, rather better (smoother, flatter), equalizing is better than not equalizing in both aspects. Of course I'm talking of the digital domain, which shouldn't add any harmonic distortion.

Also, you may apply equalizing with all its «phase distortion» without hesitation and without knowing it – if you use Chord's crossfeed.

The wish for a headphone with a flat amplitude response is a pipe dream. So if you want to make your listening experience more enjoyable and realistic, careful and deliberate equalizing is the way to go. Just for those who dare, though.

 

[Deftone]

I'm of the same mindset as Rob... as in, if you are trying to 'fix' the tonal balance of your headphones then it's time to get different headphones.

+1000

 

[Ragnar-BY]

The wish for a headphone with a flat amplitude response is a pipe dream. So if you want to make your listening experience more enjoyable and realistic, careful and deliberate equalizing is the way to go. Just for those who dare, though.

I can`t say I wish for headphones with "flat response". Human hearing is not flat.

I would not say EQ is bad. I think it is absolutely necessary when you are building car audio system. It is useful for room correction, when you are listening to speakers. It might be useful for multi-way speakers with active filtering. I think EQ could be used to improve sound in those cases. I just don`t like it with headphones.

 

[seedubchris]

@Rob Watts The filters on TT2 are implemented in SW or HW?
The FIL3 is (too) subtle as stated in TT2 manual. To make it stronger would it be enough to change a factor in the firmware?
I would love to be able to elevate bass, including and specially sub-bass, to compensate for bass light headphones.
That is the only thing holding me from ordering immediately a TT2.

The tt2 is the cure for bass light headphones . If they need more bass than the tt2 can provide than maybe better set of phones is in order

 

[JaZZ]

I can`t say I wish for headphones with "flat response". Human hearing is not flat.

I would not say EQ is bad. I think it is absolutely necessary when you are building car audio system. It is useful for room correction, when you are listening to speakers. It might be useful for multi-way speakers with active filtering. I think EQ could be used to improve sound in those cases. I just don`t like it with headphones.

Well, to each his own... concept.

However, this sentence of yours...

Human hearing is not flat.

...makes no sense.

However you call it, there's a tonal balance from a sound transducer that satisfies the human ears with natural sonic colors and realistic instrument timbres – no matter if speakers or headphones. And for someone with critical ears no existing headphone sounds neutral without equalizing. That's not to say it sounds absolutely neutral with it, but we are certainly much closer. With speakers it's relatively easy: A flat sound-pressure response at the listening place is meant to lead to a neutral tonal balance. With headphones it's more complex, as you have to apply a compensation curve taking the head-related transfer function for headphone listening into account. That doesn't mean there's no way of getting a flat perceived tonal balance from headphones, quite the opposite. Otherwise I wouldn't bother to carefully equalize my headphones and store the curves in presets.

Moreover, since you seem to care for a flat phase response: You only get that with a flat amplitude response. It also means that a perfect reproduction of transients is dependent on a flat transfer function.

...if you are trying to 'fix' the tonal balance of your headphones then it's time to get different headphones.

Again the pipe dream that there's such a headphone... Some food for thoughts by means of Inner Fidelity's collected headphone measuring graphs. Point me to a flat curve, from 20 Hz to 20 kHz! (Granted, part of the difficulty is that the compensation curve applied here leaves a lot to be desired. But I think apart from that it's still not hard to get my point.)

The tt2 is the cure for bass light headphones. If they need more bass than the tt2 can provide than maybe better set of phones is in order

It's not so much a lack of bass, rather a limited low-frequency extension that calls for equalizing. Some planars may satisfy in this respect, but the whole rest will benefit from a corresponding equalization. It would be a pity to disqualify e.g. the HD 800 just because of this well-known weakness that's in fact easy to fix.

See also the link to the Inner Fidelity graphs above!

 

[Rob Watts]

@Rob Watts The filters on TT2 are implemented in SW or HW?
The FIL3 is (too) subtle as stated in TT2 manual. To make it stronger would it be enough to change a factor in the firmware?
I would love to be able to elevate bass, including and specially sub-bass, to compensate for bass light headphones.
That is the only thing holding me from ordering immediately a TT2.

It's implemented within the FPGA, and by filter I am really talking about tweaking the interpolation filters; it's not meant as a EQ type filter, which is what you are after

You have a wrong understanding of bit perfection. The term stands for the lack of resampling, but of course any form of digital signal processing is allowed and represents no signal degradation per se – quite the opposite, if you think of an over-all linearization of a system (primarily adapted to the sound transducers' nonlinearities). Every recording you listen to has been equalized once or twice. And the filters you are expecting from your Chord DAC are digital equalizers as well. Crossfeed and digital volume control represent DSP and therefore also violate your image of «bit perfection». The M Scaler destroys bit perfection, too. So please forget it and use the proposed equalizer! Like me.

Yes I too intensely object to the term bit perfect, and the use of that term as some kind of holy grail. Actually, bit perfect NOS DACs are NOT bit perfect as sampling theory holds that the samples are of zero width, and in between samples is a virtual zero; this is true bit perfect; a NOS DAC then distorts this by replacing the zero width samples with a sample and hold filter, which has gross distortions, and huge timing errors with transients.

I much prefer the concept of signal perfect, that is exactly faithful to the original continuous analogue signal in the ADC, which the M scaler is to at least 16 bit precision. This also implies a digital domain accuracy of no amplitude changes with signal (small signal accuracy I am thinking of here), and no phase shifts with amplitude from -301dB to 0dB. Get that right and you have an audibly transparent digital path.

Well, we are consumers, so for us recorded and mastered track is a starting point. Otherwise we can discuss this for ages.

EQ may change phase and phase means time. WTA filters are all about correct time perception, so equalizer potentially could make things worse. In my opinion EQ should be used only when absolutely necessary, so I don`t use it for headphones at all.

Anyway, I hope Rob will share his thoughts about software equalization during playback.

The WTA filters are not about phase shifts per se; all symmetric FIR filters are phase linear, that is they have a constant delay irrespective of frequency. It's about the timing of transients, where a transient will be a little early or a little late, depending upon the past and future music signal, and the sampling time. Conventional interpolation filters have transients that are constantly moving back and forth in time, but the M scaler ensures that the timing of transients is independent of sampling and the signal - at least to a 16 bit accuracy.

JaZZ is correct in his post that EQ can correct for frequency and phase shifts at the same time - a perfectly flat frequency response overall implies a linear phase (it's not guaranteed, you could EQ with FIR then the phase won't get corrected for example). I do worry about IIR DSP for EQ, as I have designed these before - and getting to be signal perfect (see above) ain't no easy matter, as IIR filters are recursive, with small errors building up over time, due to internal truncation. We need to guarantee 301 dB signal amplitude linearity plus no change with phase with signal amplitude - so a -301 dB signal must have the same filter characteristics as 0dB, and that is not easy to do - and it's an issue nobody worries about, as it's simply assumed that the math precision is good enough. Even the simple act of changing the volume, and re-quantising to 24 bits with triangular dither is certainly not audibly transparent.

EQ can for sure have value; but it's often used to compensate for a distorting headphone (a bright one due to HF distortion is tamed by adding lower mid or bass), but in this sense it won't work. You just got to get a better headphone.

 

[seedubchris]

Well, to each his own... concept.

However, this sentence of yours...

...makes no sense.

However you call it, there's a tonal balance from a sound transducer that satisfies the human ears with natural sonic colors and realistic instrument timbres – no matter if speakers or headphones. And for someone with critical ears no existing headphone sounds neutral without equalizing. That's not to say it sounds absolutely neutral with it, but we are certainly much closer. With speakers it's relatively easy: A flat sound-pressure response at the listening place is meant to lead to a neutral tonal balance. With headphones it's more complex, as you have to apply a compensation curve taking the head-related transfer function for headphone listening into account. That doesn't mean there's no way of getting a flat perceived tonal balance from headphones, quite the opposite. Otherwise I wouldn't bother to carefully equalize my headphones and store the curves in presets.

Moreover, since you seem to care for a flat phase response: You only get that with a flat amplitude response. It also means that a perfect reproduction of transients is dependent on a flat transfer function.



Again the pipe dream that there's such a headphone... Some food for thoughts by means of Inner Fidelity's collected headphone measuring graphs. Point me to a flat curve, from 20 Hz to 20 kHz! (Granted, part of the difficulty is that the compensation curve applied here leaves a lot to be desired. But I think apart from that it's still not hard to get my point.)



It's not so much a lack of bass, rather a limited low-frequency extension that calls for equalizing. Some planars may satisfy in this respect, but the whole rest will benefit from a corresponding equalization. It would be a pity to disqualify e.g. the HD 800 just because of this well-known weakness that's in fact easy to fix.

See also the link to the Inner Fidelity graphs above!

I hope you can eq out the deficiency’s of the 800’s but in my experience every eq boost or cut comes with unintended and often times unacceptable reactions . Ad bass and the treble suffers and visa versa. I would say i rarely find a good result when I have to reach for an eq to fix things. I find this true for reference home stereos , iems, headphones, car stereos, and record productions. The only two fields that are exceptions in my experience are live mixing (particularly monitor mixing due to feedback control and mastering where some sculpting may be nessisary. In these cases analog passive inductor style eq are the least destructive (or at least the most phase accurate) if eq works for you by all means tweak away but the best most resolving systems I have heard never have eq as a component .its not that I or others here are racist against the eq or those that fraternize with them, it’s just that for many the easy low hanging fruit of digital eq has been shown to not be the panacea that so many hope and wish it could be for correcting their systems.

 

[musickid]

For the average layman we follow the purple light signal path on roon which indicates "bit perfect" delivery. Any added DSP changes the purple light signal to a partial blue one indicating the loss of bit perfect transmission!! beware.

 

[JaZZ]

I hope you can eq out the deficiency’s of the 800’s but in my experience every eq boost or cut comes with unintended and often times unacceptable reactions . Ad bass and the treble suffers and visa versa. I would say i rarely find a good result when I have to reach for an eq to fix things. I find this true for reference home stereos , iems, headphones, car stereos, and record productions. The only two fields that are exceptions in my experience are live mixing (particularly monitor mixing due to feedback control and mastering where some sculpting may be nessisary. In these cases analog passive inductor style eq are the least destructive (or at least the most phase accurate) if eq works for you by all means tweak away but the best most resolving systems I have heard never have eq as a component .its not that I or others here are racist against the eq or those that fraternize with them, it’s just that for many the easy low hanging fruit of digital eq has been shown to not be the panacea that so many hope and wish it could be for correcting their systems.

I wouldn't want to replace a digital EQ with an analogue EQ! Better avoid additional electronics components in the signal path, as they inevitably degrade the signal. Also, the same EQ curve leads to the very same phase distortion. Why would you expect something else? Moreover, phase distortion is absoutely desired (see above!).

Of course you can do many things wrong with equalizing. So it's definitely just for people with some patience for delving into it and learning it. Moreover you should never be satisfied with the result of your first quick attempt. It will take some time to get it right – weeks or months in my case. And every cable change or earpad replacement or M Scaler addition (!) may put you almost to square one again. You could call it a «hobby», maybe should consider it one, otherwise you would probably lose patience and interest. All I can say is that you will be rewarded once you got the knack. A really neutral tonal balance is unsubstitutable. And as theory predicts, it comes with a massively improved impulse response.

[Edit:] It wasn't my intention to scare others off from equalizing, so I'll add that a mere extension of the low-frequency response isn't rocket science. And for those who want to go further but don't feel like sacrificing the necessary time there's still Sonarworks.

 

[JTbbb]

Hello, anyone running Roon through their tt2? Any problems? My research seems to show that Hugo 2 is supported, but not tt2 at the moment?

 

[musickid]

They don't list every device made by every manufacturer. For eg my imac connected to my mscaler both are not listed. Nothing to worry about. All chord products should be pictorially represented in time. And accompanying audio preset tweaks.