In Search Of Accurate Sound Reproduction: The Final Word!

[Ralf11]

Comb filtering = bad.

[semente]

29 minutes ago, AJ Soundfield said:

Nope, I'm quoting you saying that 

 

Lateral reflections spatially average/smoothen the stereo phantom central imaging combing. Lack of reflections worsens the audible combing.

The (ears) research is clear.

 

Do they smoothen combing or just mask it?

Reflected sound is delayed.

[AJ Soundfield]

9 minutes ago, semente said:

 

Do they smoothen combing or just mask it?

Both 

 

Quote

Reflected sound is delayed.

Correct, but that isn't always bad and often very good, especially with stereo.

Again, as long as no precedence breakdown.

[AJ Soundfield]

18 minutes ago, Ralf11 said:

Comb filtering = bad.

Well, maybe 

The ear is an analyzer of limited resolution, so what can look bad pressure sampled at a single point, may not sound bad to 2 ears with central spectrum summation.

[fas42]

8 hours ago, STC said:

Ok. This is my third attempt since my last two posts have gone missing. 

 

Yes, please do show your unique setup. I am curios to know how you could that with 2 speakers. We all can learn something new. 

 

Audio samples would be great even made from cheap microphone as it could reveal room coloration easily. 

 

Thanx. 

 

A busy day today, can't engage here - but I have a YouTube channel with some very poor quality captures of what that HT rig did, https://www.youtube.com/channel/UCzkx85ez3DVxRAnpkbQEA2w/videos

[STC]

26 minutes ago, fas42 said:

 

A busy day today, can't engage here - but I have a YouTube channel with some very poor quality captures of what that HT rig did, https://www.youtube.com/channel/UCzkx85ez3DVxRAnpkbQEA2w/videos

 

Thanx for the link. I noticed that you recorded the sound from less about one meter away measured perpendicular to the two speakers. Do you listen that close?

 

[fas42]

1 hour ago, STC said:

 

Thanx for the link. I noticed that you recorded the sound from less about one meter away measured perpendicular to the two speakers. Do you listen that close?

 

 

No, it was purely because the speakers were positioned in the room such that there was only so much area where I could put up the single microphone - this is in my "work room", mess everywhere, where it's convenient to fiddle with things.

 

Note that this is not the HT machine that AJ mentioned, the recordings of that are clearly noted as such, and with those the recordings were done halfway down the house, because the gain control of the recorder overloaded, badly, if done any closer.

[AJ Soundfield]

Thanks for posting those Frank. Hard to imagine a PSR or any other MCH system extant, remotely matching the concert hall realism heard in those stereo(?) Youtube conjurings of the Phillips HTIB and other(?) system

[semente]

11 hours ago, AJ Soundfield said:

Both 

 

Correct, but that isn't always bad and often very good, especially with stereo.

Again, as long as no precedence breakdown.

 

 

I don't know if you've listened to the Sonus Faber Stradivari.

These speakers have a very wide baffle and, as a consequence, the lateral dispersion starts to narrow above the presence region in a gradual but even manner, and listening to them in a large room (16m front wall) was a very enlightening experience in regards to stereo imaging:

 

Sonus Faber Stradivari, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90 degrees–5 degrees off-axis, reference response, differences in response 5 degrees–90 degrees off-axis (source)

 

 

This is, of course, a very unToole-like approach, who defends that there shouldn't be any roll-off off-axis before we're into overtones territory:

 

Revel Ultima Salon2, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis (source)

 

 

Then we have the BBC Research Department approach.

The group research was public funded and did extensive work in speaker development both in technical and psychoacoustics terms, and they made use of experienced sound engineers and orchestras from the Broadcasting company to perform live vs. reproduced comparisons (something that would be impossible today even for the wealthiest manufacturers).

They also showed a preference for wide-baffle speakers and defended that the off-axis response should relax in the presence region as can be seen in this BBC-inspired model:

 

Harbeth Super HL5+, lateral response family at 50", normalized to response on upper-tweeter axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis (source)

 

 

Earl Gueddes goes further and proposes that power response and axial response "should fall gradually" as you enter the mid ranges "while maintaining a flat directivity index" (source).

 

 

An then you have horn speakers, such as the Avantgarde Uno which sports constant midrange and treble and directivity:

 

Avantgarde Uno Nano, lateral response family at 50", normalized to response on optimal axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis (source)

 

 

According to Toole's research the large majority will not like the horns, and from what I read in forums he is right.

What I don't agree is that using side wall reinforcement is more accurate.

 

 

But you are a speaker designer so perhaps you already know all these things.

 

R

[semente]

11 hours ago, AJ Soundfield said:

Both 

 

Correct, but that isn't always bad and often very good, especially with stereo.

Again, as long as no precedence breakdown.

 

Bad is a matter of preference, unrelated to accuracy.

[STC]

25 minutes ago, semente said:

What I don't agree is that using side wall reinforcement is more accurate.

 

Last couple of years I make recordings of my progress for reference to know exactly what I do is correct and not just placebo. Trust me the rear half wall enforcement ( provided correct and even across the frequencies) can provide you the best listening experience even with low entry system. I have sample to prove for AB.

 

Here is the video of my playback captured with a binaural recordings from my listening chair. When you listen to the sound with the headphones you should feel the ambiance enveloping you. Although, the cheap $75 dollar mic didn't capture all the low level ambiance, still you should hear the difference. Of course, the quality is limited due to cheap ambiance speakers but this sound is more realistic and better representative of actual sound.

 

At 58 seconds, only the sound of my rear half (wall enforcement is heard). As you can hear they are quiet high and yet it integrate with the main sound perfectly. Of course, Wall enforcement helps large ensemble and may not be suitable for studio recordings. 

 

https://youtu.be/PYNXNZr9a7A

 

 

 

[semente]

12 minutes ago, STC said:

 

Last couple of years I make recordings of my progress for reference to know exactly what I do is correct and not just placebo. Trust me the rear half wall enforcement ( provided correct and even across the frequencies) can provide you the best listening experience even with low entry system. I have sample to prove for AB.

 

Here is the video of my playback captured with a binaural recordings from my listening chair. When you listen to the sound with the headphones you should feel the ambiance enveloping you. Although, the cheap $75 dollar mic didn't capture all the low level ambiance, still you should hear the difference. Of course, the quality is limited due to cheap ambiance speakers but this sound is more realistic and better representative of actual sound.

 

At 58 seconds, only the sound of my rear half (wall enforcement is heard). As you can hear they are quiet high and yet it integrate with the main sound perfectly. Of course, Wall enforcement helps large ensemble and may not be suitable for studio recordings. 

 

https://youtu.be/PYNXNZr9a7A

 

 

 

 

Your system is not 2 channel stereo and you seem to be using dipole speakers so that information is not very relevant to this discussion.

 

What do you mean by "rear half wall enforcement"?

Which frequencies are you reinforcing?

How does that affect tonal balance?

I don't much care about spatial realism (soundstage, immersive or not), a reasonably credible imaging effect is just fine.

 

And I find those 2Lno recordings nonsensical...the mics/listener surrounded by instruments?

 

 

[STC]

19 minutes ago, semente said:

Your system is not 2 channel stereo and you seem to be using dipole speakers so that information is not very relevant to this discussion.

 

It is. I will add 4.) or 5.1 later.

 

Wall enforcement is basically enhancement of a frequencies with the help of the wall or convoluted speakers that act like wall. Naturally, It is impossible to to get good sound with more than 0.6second reverberation in a typical room. And here you are listening reverberation upto 2.2 seconds.

 

Is this discussion only meant for 2 speakers only or two channel stereo? (edit) Are you confusing direct sound from multi direction with ambiance from multi direction. The 2L stereo recordings are not multi channels. In that you will feel the instruments (direct sound) surrounding you . 

 

How do you determine a reasonable credible image? 

[semente]

11 minutes ago, STC said:

 

It is. I will add 4.) or 5.1 later.

 

Wall enforcement is basically enhancement of a frequencies with the help of the wall or convoluted speakers that act like wall. Naturally, It is impossible to to get good sound with more than 0.6second reverberation in a typical room. And here you are listening reverberation upto 2.2 seconds.

 

Is this discussion only meant for 2 speakers only or two channel stereo?

 

No, of course not, we can discuss other setups, just not mix them for sake of clarity.

 

Most speakers go omni below ~300Hz so there is bound to be reinforcement and floor-bounce and Allison cancellation effects at those frequencies; but as far as I know there is very little spatial information in this range.

What is your opinion regarding horns?

[STC]

On 6/9/2017 at 4:47 PM, semente said:

I've found this interesting opinion piece on the question of Live vs. Reproduced and one's ability to assess accuracy through listening.

 

 I am still here. How to reproduce accurate sound? Are two speakers enough? If they are, then I am soryy to miss the point. I ,generally, do not like horns. 

[semente]

6 minutes ago, STC said:

 I am still here. How to reproduce accurate sound? Are two speakers enough? If they are, then I am soryy to miss the point. I ,generally, do not like horns. 

 

I was hoping you'd be a bit more specific in your comment regarding (what you dislike about) horns.

 

As for your question, I would say that you need a single speaker, no more and no less, to accurately reproduce one channel; two channels, two speakers, etc.

[AJ Soundfield]

1 hour ago, semente said:

But you are a speaker designer so perhaps you already know all these things.

Yes and I've heard all the designs you've listed, Several local audiophile club members have/had Strads. There are three Trio and one Uno owners in the club, one is a AG dealer. Ditto for Salon2 and Harbeth (also have dealer in club). None of them, including my own, are "accurate", because that exists only in the minds of audiophiles/studiophiles.

 

Quote

What I don't agree is that using side wall reinforcement is more accurate.

To what?

[AJ Soundfield]

1 hour ago, semente said:

 

Bad is a matter of preference

Sure, which is why almost no one prefers the far worse combing created by killing lateral reflections with sidewall absorption...ears only, the opposite of what studio fashions/treatment believers advocate. Again, the research is very clear here. Without the spatial averaging (similar to what happens with multi-subs smoothing effect), the stereophonic comb filtering is worse. That's a physical fact. Ears prefer less combing.

Audio/Studiophile eyes OTOH....

 

Quote

unrelated to accuracy.

To what?

[semente]

4 minutes ago, AJ Soundfield said:

Yes and I've heard all the designs you've listed, Several local audiophile club members have/had Strads. There are three Trio and one Uno owners in the club, one is a AG dealer. Ditto for Salon2 and Harbeth (also have dealer in club). None of them, including my own, are "accurate", because that exists only in the minds of audiophiles/studiophiles.

 

To what?

 

This is how I see it: if you play a signal through a speaker in an anechoic chamber this will define the speaker's accuracy.

When you move the speaker into a room, the degree in which the room affects the transduced signal depends on the way sound (through directivity) interacts with the room before it reaches the listener.

 

You may have heard about an experiment that Gradient Labs performed many years ago in which they compared the accuracy of several speakers by inserting a speaker into one channel.

The speaker would reproduce the signal/music in an anechoic chamber and this sound was then fed live into the corresponding speaker of the 2 channel setup placed in a listening room.

[mansr]

3 minutes ago, semente said:

You may have heard about an experiment that Gradient Labs performed many years ago in which they compared the accuracy of several speakers by inserting a speaker into one channel.

The speaker would reproduce the signal/music in an anechoic chamber and this sound was then fed live into the corresponding speaker of the 2 channel setup placed in a listening room.

What was the outcome?

[STC]

51 minutes ago, semente said:

I was hoping you'd be a bit more specific in your comment regarding (what you dislike about) horns

 

Besides childhood hatred for anything to do with horns ( something to do with goats), I find they can be shouty with vocals. But they also do sound great with sax. 

 

Just an opinion with limited exposure with horn speakers, although I get plenty of exposure with pro sound horn speakers. 

 

I think it it safe to say, I have no opinion since never owned one nor spend enough time with them to form an opinion. 

[AJ Soundfield]

11 minutes ago, semente said:

 

This is how I see it: if you play a signal through a speaker in an anechoic chamber this will define the speaker's accuracy.

When you move the speaker into a room, the degree in which the room affects the transduced signal depends on the way sound (through directivity) interacts with the room before it reaches the listener.

So an "accurate" listening room is an anechoic chamber.

While my microphones would agree, my ears do not.

Quote

 

You may have heard about an experiment that Gradient Labs performed many years ago in which they compared the accuracy of several speakers by inserting a speaker into one channel.

The speaker would reproduce the signal/music in an anechoic chamber and this sound was then fed live into the corresponding speaker of the 2 channel setup placed in a listening room.

 

Yes, I'm an AES member and acutely aware of Salmis work, including his Absolute Listening Test.

It does not conflict with the current research, unless misunderstood. I'm linking articles too.

Reflections per se are not perceptually "bad", unless spectrally disambiguated from their onsets ("direct" response).

Once again, the research is clear. Unfortunately, a lot of folklore persists, but 'tis the way of this world.

 

[semente]

1 hour ago, mansr said:

What was the outcome?

 

I don't know which speakers were tested but as far as I remember the only one that was not identified as being in the chain was the BnW 801F.

[semente]

1 hour ago, AJ Soundfield said:

So an "accurate" listening room is an anechoic chamber.

While my microphones would agree, my ears do not.

Yes, I'm an AES member and acutely aware of Salmis work, including his Absolute Listening Test.

It does not conflict with the current research, unless misunderstood. I'm linking articles too.

Reflections per se are not perceptually "bad", unless spectrally disambiguated from their onsets ("direct" response).

Once again, the research is clear. Unfortunately, a lot of folklore persists, but 'tis the way of this world.

 

 

I am not contesting that they are not ' perceptually "bad" '; in fact research shows that is what most people seem to prefer. I prefer a "dryer" sounding room, or less room contribution if you prefer but that is just a matter of taste.

 

I have browsed your website when you started contributing to CA, it would be interesting to have a look at the measurements of your larger speakers.

 

R 

[AJ Soundfield]

2 hours ago, mansr said:

What was the outcome?

 

That the terrible off axis and modal excitation of most loudspeakers, were the main source of perceived signal chain "coloration" in real rooms.

 

 

I've got the paper buried somewhere, snap shot above gives idea of age. "record" being vinyl