Live vs. Reproduced?

[RogerD]

Frank,

that thread should be interesting. I agree the speaker should be invisible from anywhere in the room and off axis too. It is recording dependent to a point,but the majority of good recordings,that are well engineered should produce the effect. That's why I say if you are there,don't touch a damn thing.

 

[RogerD]

There was a whole thread some time back on this, "Invisible Speakers". My point is that the speakers should be invisible from anywhere in the room, not just around the prime listening position. This includes standing a couple of feet diagonally left of the left speaker, say. Most systems would fail to sustain the illusion at this point; my friend who's working hard on the analogue side of things has got it sounding very clean and musical on old recordings, nice soundstage in the middle but his speakers still are too obvious away from this spot.

Frank

Holy moly,just read about half of that thread, I think I will keep quiet about this. Frank you can carry the water just fine.

 

[silviajulieta]

Dear Steve Williams: Yes, I know it.

regards and enjoy the music,
raul.

 

[silviajulieta]

Dear Mike Lavigne: +++++ " reality is more that best performance " +++++

I agree, we have no " differences " here: finally!


Regards and enjoy the music,
Raul.

 

[silviajulieta]

Dear fas42: +++++ " I emphasise low disortion because " +++++

perhaps this is the main subject where I agree with you.

Some people on this thread and many on Agon know that when I test any audio item I tested at normal SPL: 83db-84db continuous with peaks at 90dbs and I tested at higher SPLs too: 94db-95db continuous with peaks at around 102dbs, all these at seat position. Sometimes I try it harder higher SPLs. Yes, the high SPL test is agood one to " prove " any audio system quality performance.

A system real test is with high SPLs where if the system is not up to the task we heard how the whole music presentation change for the worst, each music/sound performance audiophile characteristics ( inner detail, deep image, focus, dynamics, etc, etc. ) change and suffer a transformation only the best systems ( the lowest distortions is a must . ) mantain the overall " aplomb " under high SPL tests. But even those " best systems " IMHO can't mimic the live music event with out a big/great/crazy imagination.

Anyway, you already make your point: good luck.

regards and enjoy the music,
raul.

 

[fas42]

A system real test is with high SPLs where if the system is not up to the task we heard how the whole music presentation change for the worst, each music/sound performance audiophile characteristics ( inner detail, deep image, focus, dynamics, etc, etc. ) change and suffer a transformation only the best systems ( the lowest distortions is a must . ) mantain the overall " aplomb " under high SPL tests. But even those " best systems " IMHO can't mimic the live music event with out a big/great/crazy imagination.

Anyway, you already make your point: good luck.

Raul, how well would you say your system performs this test I mentioned before:

"There is a simple test I use, with your system working at a good "live" volume, can you walk up to the tweeter of one channel and not be able to hear it working; in other words, the speaker assembly is totally audibly invisible no matter how close you get to it?"

If I am not correct please correct me in the following: your monitor speakers are 95dB sensitive, the Levinsons are 100 watts class A, well within what the speakers can comfortably handle, therefore at 1 metre from one channel you should be able to listen to clean 115db peaks, at 2 metres clean 109dB peaks. In stereo listening at 3 metres that same 109dB peak should be comfortable listening. Would this be right?

Frank

 

[garylkoh]

"There is a simple test I use, with your system working at a good "live" volume, can you walk up to the tweeter of one channel and not be able to hear it working; in other words, the speaker assembly is totally audibly invisible no matter how close you get to it?"

Frank, sorry, but you keep making this point, and it's something that I absolutely don't get. When my system is playing, and it's playing right, if I disconnect the tweeter, I can ABSOLUTELY hear the difference..... and I cross over the tweeter higher than most. I don't get if you are talking about a 2-way system or a 3-way system or a 4-way system...... I've encountered 2-way systems where the tweeter crossed over at as low as 1kHz. Are you saying that you cannot hear the tweeter then either?

Speaker designers have an integration point in mind when they design the crossover between a tweeter and a midrange. For me, it's further. For others, it's nearer. That is why I say that my speakers are absolutely NOT near field monitors. I know that there are some speakers that you can hear the lobing between the drivers when you move your head - even at the listening position 10 ft away. But I gather that you are not talking about this.

Please enlighten me.

 

[RogerD]

Hello Gary,

I haven't done the Frank test yet don't know if I need to. I want to ask if what some experience as "invisible" speakers,what would need to be done on a engineering level to achieve this? I would imagine the the drivers would have to be phase coherent and time domain correct.

P.S. I will be a gentle soul to your response, If I am misinformed please enlighten me also.

Roger

 

[Phelonious Ponk]

I think I've read most of what Frank has written about this invisible speaker effect, and I'm still completely at a loss as to what he means. Typically, when we talk of invisible speakers, we're talking about speakers that image so well, create such a palpable phantom center, center left, center right, right, left, beyond left, etc., etc., that when you're sitting in front of them the disappear; you have the instruments laid out in a plane in front of you and the position of the speakers themselves cannot be heard.

But that can't be what Frank is talking about, because he tests his speakers' invisibility by walking right up to one and putting his ear up to the tweeter, which he can't "hear," whatever that means.

Then I thought, maybe Frank is talking about coherency, the ability of a speaker to blend at the listening position, so the listener cannot hear the physical and frequency separation of the individual drivers in the system.

But this can't be what Frank is talking about because, again, he's putting his ear right up to the tweeter, and doesn't "hear" the tweeter. In fact, at that point the tweeter is all Frank is hearing; he has essentially created a monophonic tweeter headphone. There is nothing to be heard but the tweeter.

I contemplated a couple of other possibilities within a normal to moderately sophisticated understanding of audio reproduction, only to come up against similar dead ends. Regrettably, I haven't a clue what Frank's invisible tweeter is.

Tim

 

[garylkoh]

Hi Roger,

I seriously cannot figure out how the Frank test would work. He's probably a better loudspeaker/ system designer than I am if he can do that because I can't.

When you get closer to the speaker than a distance at which the tweeter and midrange coheres, you can absolutely hear the difference between the tweeter and the midrange. It's the laws of physics - the tweeter and midrange have separate centers, and the wavelengths have a finite length. At the crossover frequency, if the center of the tweeter and the center of the midrange are not coincident you can hear and measure the separation even if they are absolutely perfect in phase coherence.

If he had said woofer and midrange, I can believe that with some speakers, when the midrange goes low enough and distance between the midrange and woofer is less than 1/4 wavelength, it is possible.

Getting to the second part of your question, besides phase coherence and time domain, I believe that you have to have the power dissipation correct. I'm not prepared to say more about how I go about achieving this. Sorry about that. I know that some will call BS on me (I'm not implying you).

You can achieve what I call the "sonic shadow" test. Sit and listen to the speakers, and have someone walk across the room between you and the speakers. If you do not hear a "shadow" go across the room (especially when he is standing between you and the speakers), you have achieved "invisible" speakers.

I demo'ed this to Amir when he came to visit. I think he might have heard it. Every audiophile I've demo'ed this to have been visibly surprised. Non-audiophiles, on the other hand, are NOT surprised, because when you are at a live performance, when someone walks between you and the performer, you see her, but do not hear her.

 

[RogerD]

Gary,

Thanks so much. I understand completely.

 

[silviajulieta]

Raul, how well would you say your system performs this test I mentioned before:

"There is a simple test I use, with your system working at a good "live" volume, can you walk up to the tweeter of one channel and not be able to hear it working; in other words, the speaker assembly is totally audibly invisible no matter how close you get to it?"

If I am not correct please correct me in the following: your monitor speakers are 95dB sensitive, the Levinsons are 100 watts class A, well within what the speakers can comfortably handle, therefore at 1 metre from one channel you should be able to listen to clean 115db peaks, at 2 metres clean 109dB peaks. In stereo listening at 3 metres that same 109dB peak should be comfortable listening. Would this be right?

Frank

Dear fas42: Even the amps headrrom improves a little ( well not the design headroom. ) because those monoblocks run from 80hz and up and are working usually with a speaker impedance on the 2.5-3.0 ohms and this means that those ML amps are not 100watts units but around 400 watts.

I measured 100dbs ( SPL ) continuos at 3 meters ( 110db on peaks. ) with comfortable listening but only briefly.

I could do your test but before I do it I need that you give me the name of the LP/CD under test and which tracks and with which SPL ( continuos and peaks. ) at which precise distances. The other " problem " is that I'm not sure that I want to take that risk with my ears that are the ones that give me the opportunity to enjoy music.
I know that with low level distortions ( as in my system ) we can tolerate more SPL but I don't know how much with out permanent damage.

Anyway, please give me the information about and we will see.

regards and enjoy the music,
Raul.

 

[mep]

But that can't be what Frank is talking about, because he tests his speakers' invisibility by walking right up to one and putting his ear up to the tweeter, which he can't "hear," whatever that means.

I seriously cannot figure out how the Frank test would work. He's probably a better loudspeaker/ system designer than I am if he can do that because I can't.

There are only two plausible explanations for Frank's *invisible* tweeter. Either the tweeter is broken which I stated before; or, Frank's high frequency hearing is shot due to all the loud listening he does and he truly can't hear his tweeter. Take your pick, it's one or the other.

 

[fas42]

I seriously cannot figure out how the Frank test would work. He's probably a better loudspeaker/ system designer than I am if he can do that because I can't.
...
You can achieve what I call the "sonic shadow" test. Sit and listen to the speakers, and have someone walk across the room between you and the speakers. If you do not hear a "shadow" go across the room (especially when he is standing between you and the speakers), you have achieved "invisible" speakers.

I demo'ed this to Amir when he came to visit. I think he might have heard it. Every audiophile I've demo'ed this to have been visibly surprised. Non-audiophiles, on the other hand, are NOT surprised, because when you are at a live performance, when someone walks between you and the performer, you see her, but do not hear her.

Gary, thanks for your input. I am very impressed with what Roger has done, it sounds as if he has "got" it, or if not, it is so close that only a small extra effort would take it all the way. The key thing he said, in another post today, was "But the big surprise was the next day after about 12 hours. while listening everything in the electrical chain must have re-equalised because the sound morphed into a spectacular reproducton of what was recorded. About as close to in house 'live" music as I have ever experienced". This is exactly what occurs when enough is done to reduce the noise floor as Roger and others call it, and what I term minimising low level distortion.

There are many attributes of this "better" sound, and one of them is the invisible speaker thing. As Roger says, he almost feels that he doesn't have to try it, because he knows it will work, or close enough to it.

So why does it work? I have tried to describe my take on this several times, using the terms psychacoustic, ear/brain compression , and now I can also use sonic shadow. Remember, I am not saying that the tweeter is not working, it is just that the wall of sound, for want of a better term, is so convincing to the mind, as processed through the ear/brain mechanism, that it can't or is not interested in tuning in to the tweeter as being the true source of the sound. Another way of describing it: if my system is not firing then I can walk up to a speaker, and it sounds just like a normal speaker. It's obvious where the sound is coming from, if I close my eyes I can easily point to where the driver is, if I put my head down it's dead obvious that the very high frequency sounds are coming from a different point than the rest. But, when it is on song that ability to discern where the sound comes from disappears: there is just a blanket of realistic sound which does not vary whichever way I move my head, up, down, left, right, back and forth.

Tim has experienced this with his near field listening on a mono source, moving his head to the left and right. What I am describing is in essence exactly the same thing, just taken to another level of "palpability", shall we say.

Frank

 

[fas42]

I measured 100dbs ( SPL ) continuos at 3 meters ( 110db on peaks. ) with comfortable listening but only briefly.

I could do your test but before I do it I need that you give me the name of the LP/CD under test and which tracks and with which SPL ( continuos and peaks. ) at which precise distances. The other " problem " is that I'm not sure that I want to take that risk with my ears that are the ones that give me the opportunity to enjoy music.
I know that with low level distortions ( as in my system ) we can tolerate more SPL but I don't know how much with out permanent damage.

I'm pleased that I managed to get a pretty good score on estimating your system's capability ! My little HT setup, at 1 metre I estimate would only be capable of 105dB peak, you have at least another 10dB, possibly 15dB above that. Tim, I have tracked down some figures, and you should be capable of 116dB peak at 1 meter, well above me. So both of you gentlemen should easily be able to outgun me on raw horsepower needed ...

A test recording? When the system is humming it will work for any recording, but an easy, obvious starter would be a nicely played violin solo, one that has good, sweet tone. You should be able to go up the tweeter as stated and not lose any of that tone: if it starts to become harsh and edgy the closer you get to the tweeter then the invisibility thing won't work, there's still too much distortion in the system. If you don't lose the tone on that recording try a more "difficult" violin recording, and so on ...

As regards ear damage, as you say, low distortion minimises problems. For me, I start to get ringing in the ear which is the body's way of telling you to back off, which I immediately do. You only have to do the test momentarily, a few seconds will give an answer either way.

Frank

 

[DonH50]

I'm not sure that I want to take that risk with my ears that are the ones that give me the opportunity to enjoy music.
I know that with low level distortions ( as in my system ) we can tolerate more SPL but I don't know how much with out permanent damage.

You are wise to protect your ears.

I disagree with your second statement. In my experience, low-distortion systems are MORE dangerous because they allow us to play louder than we would if it got all distorted and forced us to cut the volume. The sound level that causes damage varies with frequency, but the total power into your ears does the damage, distorted or not.

 

[fas42]

You are wise to protect your ears.

I disagree with your second statement. In my experience, low-distortion systems are MORE dangerous because they allow us to play louder than we would if it got all distorted and forced us to cut the volume. The sound level that causes damage varies with frequency, but the total power into your ears does the damage, distorted or not.

Well timed, Don! As I just mentioned, ringing in the ears is an excellent tell tale, which I always react quickly to. An idiot at the end of the high school celebrations fired a starter pistol right next to my right ear, it took months to recover, and to this day it is always the first to play up. My hearing is still good enough though to pick up an 18kHz tone happening, when I warm up the DAC, so I haven't done too much more damage!

If musical intensity is bad for our ears, then how do the players in an orchestra survive?

Frank

 

[JackD201]

"Plus 2 at 2"

It's a cliche about this difference in preference between musicians and audiophiles. Plus 2 at 2 is Plus 2dB at 2kHz for musicians and down 2dB for audiophiles.

I'd love to see a study if there is any truth to this. I'd say it fits but "Plus 2 at 2" appears to hold just as true between two musicians or between 2 audiophiles, anecdotally.

I'd think orchestra players are in no way as much danger as rock musicians. There aren't very many pieces that play at full tilt for sustained periods of time.

 

[DonH50]

"If musical intensity is bad for our ears, then how do the players in an orchestra survive?"

Ask the poor bassoons who sit in front of me, especially when they resorted to ear plugs last concert when the conductor wanted the ending at full blast (nothing like high concert C's, D's, and E's at FFFF from a trumpet a meter behind you!) I also play in wind and big bands, and have spent plenty of time in rock bands (more as sound man than musician, however). At a community musical, they made a little space in front of me as the sustained high notes (high Gs to double Ds, fun stuff!) were too loud for the players in front of me. I did try a little softer, but when the score says "fff" and the conductor wants more so I carry over the band, what the heck!?!

Seriously, there have been all sorts of studies showing musicians' (and audiophiles, and construction workers, tarmac workers, etc.) hearing damage over time -- Google it, or check out AES and AMA journal articles. I think the tie to volume and hearing loss is well-established. And yes, it's far worse in pop/rock bands, as the sustained levels are higher, there tend to be more HF overtones from distortion (intentional or not), and compressed dynamics make the average higher than in an orchestra.

At 51, and after years of ear abuse, my hearing cuts off between 10 and 12 kHz (down from 22 kHz in college) and I have slight but permanent tinnitus. It's no joke. Do what you want, I learned my lesson the hard way, and too late.

Jack, the "plus 2 at 2" statement is news to me. I will note that our hearing peaks around 3 kHz, not coincidentally (IMO) about where a baby's cry peaks...

 

[Phelonious Ponk]

I put my head down it's dead obvious that the very high frequency sounds are coming from a different point than the rest. But, when it is on song that ability to discern where the sound comes from disappears: there is just a blanket of realistic sound which does not vary whichever way I move my head, up, down, left, right, back and forth.

So when you say the tweeter disappears you're saying is that you can't discern between the woofer and the tweeter when your head is right in front of the speaker? And that this blanket of the speaker's full range output moves with you when you move your head? When you move your head to the left the audio follows, you don't have the sensation of the music moving to the right? This is good, or at least if makes more sense. Not sure it has anything at all to do with soldering mains cables to outlets, but it makes more sense. Well, half of it makes sense...

Tim has experienced this with his near field listening on a mono source, moving his head to the left and right. What I am describing is in essence exactly the same thing, just taken to another level of "palpability", shall we say.

Actually, this works in stereo as well. This is just good imaging, a phantom center so solid that it seems to move left and right on a track, staying directly in front of my head as I slide back and forth in front of the speakers. The effect is not exclusive to near field listening. I have duplicated it with good speakers set to image best at my standing height, where I could move back and forth between them from 10 - 12 feet away. If you have good enough imaging - a result of very clean electronics, speakers with excellent dispersion and off axis response, and a listening distance far enough back for the drivers in the speakers to blend properly - this should work in any room with good reflection control.

None of this is going to happen, however, when your ear is only inches from the tweeter. I have no idea what could do that, and that's what I thought I had heard you say in the past.

Tim