Did everyone lie about all pass filters?

[ruffrecords]

Abbey, would you care to comment on the corresponding effects in headphones?

Cheers

Ian

 

[abbey road d enfer]

Abbey, would you care to comment on the corresponding effects in headphones?

First, I hate headphones for listening, I'm utterly incapable of mixing with headphones. I use them exclusively for foldback in recording, and sometimes for identifying noises or other signal impairments.
Now, I think that the dominant effect of panning with headphones is the virtual source displacement, which, for me, completely obliterates any other effect.
I must admit I never dig much into HRTF decoders that may (or may not) overcome this issue.
I would add that the answer for the loudspeaker case is essentially a matter of physics (that are easily verified by measurements), when it's a matter of psychoacoustics in the case of headphones.

 

[user 37518]

Sound pressure is not a vector, it's an algebraic value.

I think you actually mean a scalar, not algebraic value.

 

[abbey road d enfer]

I think you actually mean a scalar, not algebraic value.

Quite right, Profesor . Happens more and more often, I miss the right word, write something that I think is similar. If it comes back to me I edit the post...or do nothing...

 

[user 37518]

Quite right. Happens more and more often, I miss the right word, write something that I think is similar. If it comes back to me I edit the post...or do nothing...

Happens to me as well....

 

[ccaudle]

Happens to me as well....

I'm just glad you guys are so fluent. I would just give up if I had to switch between English, Spanish, and French, German,... to read forum posts.

 

[Gold]

The conservation of SPL will be verified in the median plane only, and there will be zones with much less SPL, due to cancellation.
Validity of the concept depends on how the pressures from separate sources are correlated, or how accurately two sources combine and result in doubling.
Measurements have been conducted in many studios and auditoria that show that the correlation is very good in most studios, with an average of about 5.5dB, which clearly shows that the constant-power PP is inadequate.
Correlation is not so good in many venues, with a an average of about 4.5dB instead of 6. It's predictble, since the speakers are usually much more separated. That's the reason why many live desk manufacturers opted for PP with -4.5 dB in the center position.

For the less technically inclined, the accuracy of the pan pot center position depends on the accuracy of the acoustic summing of the left and right speaker(s) in space.

 

[abbey road d enfer]

For the less technically inclined, the accuracy of the pan pot center position depends on the accuracy of the acoustic summing of the left and right speaker(s) in space.

Thanks for the translation!

 

[user 37518]

I'm just glad you guys are so fluent. I would just give up if I had to switch between English, Spanish, and French, German,... to read forum posts.

One gets used to it, 95% of all the literature I've had to read during my education as an engineer is in English, it is the lingua franca of today, back in the day, Esperanto was supposed to be the an attempt to create a common language for the world, it quickly became useless as English essentially fulfilled what Esperanto intended to do, but some people think it will be supplanted by Chinese in the future.

 

[FIX]

Thanks sdimond for the reference!! Now I understand why they're called "Dome filters" ... my mystery of the day solved!

We rack our brains trying to figure out why they were called a dome filter, only to realize it was someone's name...

 

[FIX]

My goal was to make a panner that made no difference with the position if summed to mono. I never went for a filter because in real life, a mono receiver (FM stereo off) would simply sum L+R (from the source), and in as music distribution system, it would sum L+R, so I opted for the same. My mono switch sums L+R direct from left and right.

Since no one ever made a real pan pot (audio taper pots are overlays of resist, 2, 3 or 4 times depending on the quality, and then slugged to ground), I went for the linear pot grounded in the center, and then buffered it back up to unity. Works like a champ.

 

[abbey road d enfer]

In the 90's, I designed a spectrum-steering pan-pot, which consisted in boosting HF content on one side whilst substracting the same amount from the opposite side. 100% mono compatible.
I submitted it to Soundcraft, who took the time to evaluate it, but, although the cost was modest, concluded that it would not constitute a competitive advantage. I found out it requires some education to understand the benefits; when people see that the signal does not fully disappear on one side, they think it's broken.

 

[ruffrecords]

First, I hate headphones for listening, I'm utterly incapable of mixing with headphones. I use them exclusively for foldback in recording, and sometimes for identifying noises or other signal impairments.
Now, I think that the dominant effect of panning with headphones is the virtual source displacement, which, for me, completely obliterates any other effect.
I must admit I never dig much into HRTF decoders that may (or may not) overcome this issue.
I would add that the answer for the loudspeaker case is essentially a matter of physics (that are easily verified by measurements), when it's a matter of psychoacoustics in the case of headphones.

I am interested because a lot of music these days is listened to on headphones of one sort or another.

Cheers

Ian

 

[ruffrecords]

One gets used to it, 95% of all the literature I've had to read during my education as an engineer is in English, it is the lingua franca of today, back in the day, Esperanto was supposed to be the an attempt to create a common language for the world, it quickly became useless as English essentially fulfilled what Esperanto intended to do, but some people think it will be supplanted by Chinese in the future.

When I was at secondary school back in the 60s I was encouraged to learn German because all the best electronic books were written in German. How times change.

Cheers

Ian

 

[abbey road d enfer]

I am interested because a lot of music these days is listened to on headphones of one sort or another.

Cheers

Ian

I know, but who can swear the reason is it's because it sounds better?

 

[user 37518]

When I was at secondary school back in the 60s I was encouraged to learn German because all the best electronic books were written in German. How times change.

Cheers

Ian

Before the 40s up to the early 80s. most engineering books used at the universities here in Mexico were translated to Spanish, some of them came from the US/Europe some were from the USSR, I have a few of those books translated from Russian to Spanish, and its amazing how the Russians have a completely different vision of the same topics, I am not saying better, but different.

All my education is based on the Western/US model, but its interesting to read those Soviet books, sometimes they use completely different names for the same thing, for instance, there is no such thing as the Nyquist/Shannon theorem, but the Kotelnikov theorem, there is no Cauer or Elliptic filter, but the Zolotarev filter, and so on... Also, the way they approach circuit analysis and mathematics is completely different.

After the fall of the Soviet Union, many ex-Soviets came here to Mexico, public universities are still full of them. So, there is a heavy Russian/Ukranian or USSR in general bias, not as much as back in the 90s but it still prevails. They are also very nationalists, I remember one of them, around 4 years ago during a Keysight presentation, one of the sales engineers asked an ex-soviet professor "Do you speak english" and he said "Yes, but I prefer Russian" haha If there are two brands of software, one of the from the US, the other from Europe, they will use the European one, just because they still don't like the Americans....

 

[user 37518]

In the 90's, I designed a spectrum-steering pan-pot, which consisted in boosting HF content on one side whilst substracting the same amount from the opposite side. 100% mono compatible.
I submitted it to Soundcraft, who took the time to evaluate it, but, although the cost was modest, concluded that it would not constitute a competitive advantage. I found out it requires some education to understand the benefits; when people see that the signal does not fully disappear on one side, they think it's broken.

That sounds like a good invention! But yes, there probably would've been a lot of user complaints about broken pan pots, its basically like changing the QWERTY keyboard to something different

 

[MicMaven]

I know, but who can swear the reason is it's because it sounds better?

It is not better. People use headphones for a myriad of practical and circumstantial reasons, not always because they sound better. There is a big market for them (not news.) For example, I use headphones on my amateur radio station because they provide 23 dB passive noise attenuation, blocking noise from cooling fans, barking dogs, marauding grand children, and my wife asking me to mow the lawn. Headphones allow consumers to listen privately, blocking ambient sound, and to listen at higher volumes than neighbors in high density living arrangements tolerate, etc. I believe it is a mistake to mix audio solely for consumption via speakers, when so many use headphones so often.

I concede, of course, if headphones sound better than speakers, it is the fault of the speakers! This is just MY uneducated take ... your mileage may vary. JR

 

[abbey road d enfer]

It is not better. People use headphones for a myriad of practical and circumstantial reasons, not always because they sound better. There is a big market for them (not news.) For example, I use headphones on my amateur radio station because they provide 23 dB passive noise attenuation, blocking noise from cooling fans, barking dogs, marauding grand children, and my wife asking me to mow the lawn. Headphones allow consumers to listen privately, blocking ambient sound, and to listen at higher volumes than neighbors in high density living arrangements tolerate, etc.

As you may have guessed, I'm not denying all these reasons, but they're a clear demonstration that the ultimate reason for using them is not sound quality, it's practicality. Same reason why I use cans for musician foldback in recording, because speakers are imptactical
. I know that many people have spent many hours for providing the best listening experience with headphones, but I just can't live with the discrepancy between audible and visual cues (I know there are some systems that use gyroscopes to generate steering) and the everlasting "center-in_head" effect.
I remember when the first i-phones came out, and people around me were marvelling at the sound quality of their headphone output.
Impressive, yes, but accurate, no...

I believe it is a mistake to mix audio solely for consumption via speakers, when so many use headphones so often.

It's an interesting comment. ATM, AFAIK, most mixes are intended for speaker listening, and the task of transcoding format for headphones is assigned to the final user, who has to provide a HRTF coder.
I don't know how pleased record companies would be if they add to provide, in addition to the CD mix and the more and more frequently required vinyl mix, headphone-specific versions thereof...

 

[Newmarket]

Doesn't seem very practical to second guess headphone vs speaker usage in terms of the mix delivered to the user imo.
eg I use TIDAL streaming service. I might be listening via mobile phone on earbuds. Then plug that into the car aux input when driving. Then take it home and plug it through my system and listen on monitors and/or 'studio headphones'.