Are audio companies all involved in a huge conspiracy? - Page 54

Please explain how an amp "controls" a speaker.

A very simple look:

http://www.whatsbestforum.com/showthread.php?8103-Example-Amplifier-Responses-into-Speaker-Loads&p=139289#post139289

Some of us understand how speakers and amplifiers interact quite well. And still think the vast majority of amplifiers, operated well within their specifications, driving the majority of speakers, will in fact sound the same.

x
Edited by kraut - 3/5/13 at 7:01pm

You are welcomed to use your non-damaged ears to prove me wrong as you are so certain that mine are broken. The Krell and audiosource look like good candidates. If you can demonstrate your ability to correctly identify these amps using your ears, I will publicly admit my ignorance, my deafness, your ability, and throw in some cash for your effort. I am quite confident that your supposed ability is an auditory hallucination.
Oh man, the irony!
Ah, one of the favorite distractors of audiophools... list your gear! If it doesn't meet my approval, you aren't qualified to offer an opinion!

Let me ask... have you ever jumped out of a plane without a parachute? Do you need to list all of your attempts, at what altitudes, and at what flight speeds to be qualified to render an opinion on what would happen if someone else tried? Right. Your requirement is just as stupid. Asking me to list equipment that would be stupid to purchase before accepting that I have a valid opinion about the stupidity of paying for name and placebo is no different. Glad we have that out of the way.

To oblige, my first amps were a stack of rotel stereo amps many years ago. They fit into my budget, had the simple black box look I liked, good specs, and because this was when I was still stupid about such things, were well reviewed and supposedly had "good sound beyond their modest price." Good solid gear, still have several in storage. Maybe had i know better I could have found a cheaper acceptable alternative. Who knows. First speakers to go with them were all Maggie's and velodyne, the L/R consisting of modified actively biamped 2.7 qr's.

Currently the best speakers not in storage but in active use are the cheap earbuds I use with my phone and iPod. That's what a career move and rigorous but fortunately temporary training period will do for you.

In between were lots of amps and speakers, the speakers mostly of my design and build sold to customers, the best sounding some actively biamped dynamic driver dipoles using the original icepower modules (for a while I was an OEM customer of B&O).

The current speaker design for the theater being drafted in our future house plans calls for nearly $6k in raw driver cost per channel. To be honest, I'm not sure if I'll actually go through with that design because I think I can achiever close to that level of performance with only $2600 in raw cost per channel. Whatever I build, it will be powered with something capable but inexpensive... prosound amps if hidden and sound isolated, something like ATI, outlaw or emotiva if exposed.

I've heard plenty of uberexpensive amps but fortunately became educated before I was seriously tempted to waste money on any of them.

Now that I've obliged your ridiculous request, I await your demonstration of my deafness.
Edited by Bigus - 3/5/13 at 8:56pm

As am I.
A classic example is the Zipser test (Yamaha integrated vs Pass). It's in the letters section (near the end).

Back around 1984 when I was young and still drinking the audiophile kool-aid, I bought a Krell KSA-100 for $3000. It received rave reviews in HFN & RR, where they praised its ability to drive the 1 Ohm Apogee Scintilla. They did mention that their sample had a problem with buzzing relays, but that a replacement from Krell fixed that. Uh huh.

So I brought it home. Guess what? Buzzing relays. Got some new ones from Krell, and they buzzed too. I just collected the ones that buzzed the least and used them.

After about a year, the power switch, a breaker made by Airpax, went south. I got a new one of those from Krell too. It connected to the input AC power via lame push-on connectors, so no soldering required.

It made a great heater, but this was not so good in apartments on the California coast, as they typically have no air conditioning.

I finally got rid of the thing. I sure don't need a 100 lb. electric heater for the summer months in Texas, where it gets over 105 degrees F. I'm sure I could identify the presence of the KSA-100 blind in a quiet room with no music playing at all - just listen for the buzzing relays. But hey, the front panel is about a quarter of an inch thick, and that's what counts.
Edited by andyc56 - 3/7/13 at 7:28am

Up until the loudspeakers, it's indeed electrical signals we are reproducing. There's nothing else being sent in the cables, no magic entities. Any damage to the signal done, damages the sound. (That's why 'integrity' was used in the other post) All the 'magic' of turning the electrical signal into music happens in the loudspeaker, it only needs an undamaged signal and enough power to do it's job. It's also a huge job hanging on YOUR shoulders to mate speakers, room and the placement of them in it. There's enough degrees of freedom in that to complicate your hifi-life, you really don't need to worry about more components... you ought to be happy there is an engineering approach to use.

That one?

"There has been a lot of hot chatter on the E-mail circuit over the past couple of months about the Steve Maki and Steve Zipser challenge in Miami. I thought you would appreciate a complete recount of the events. Zipser, a high-end salon owner, had issued a challenge that he would pay the airplane fare of any interested party who wanted to see him prove he could hear the differences between amplifiers.

On Sunday afternoon, August 25th, Maki and I arrived at Zipser's house, which is also Sunshine Stereo. Maki brought his own control unit, a Yamaha AX-700 100-watt integrated amplifier for the challenge. In a straight 10-trial hardwired comparison, Zipser was only able to identify correctly 3 times out of 10 whether the Yamaha unit or his pair of Pass Laboratories Aleph 1.2 monoblock 200-watt amplifiers was powering his Duntech Marquis speakers. A Pass Labs preamplifier, Zip's personal wiring, and a full Audio Alchemy CD playback system completed the playback chain. No device except the Yamaha integrated amplifier was ever placed in the system. Maki inserted one or the other amplifier into the system and covered them with a thin black cloth to hide identities. Zipser used his own playback material and had as long as he wanted to decide which unit was driving the speakers.

I had matched the playback levels of the amplifiers to within 0.1 dB at 1 kHz, using the Y amaha balance and volume controls. Playback levels were adjusted with the system preamplifier by Zipser. I also determined that the two devices had frequency response differences of 0.4 dB at 16 kHz, but both were perfectly flat from 20 Hz to 8 kHz. In addition to me, Zipser, and Maki, one of Zip's friends, his wife, and another person unknown to me were sometimes in the room during the test, but no one was disruptive and conditions were perfectly quiet.

As far as I was concerned, the test was over. However, Zipser complained that he had stayed out late the night before and this reduced his sensitivity. At dinner, purchased by Zipser, we offered to give him another chance on Monday morning before our flight back North. On Monday at 9 a.m., I installed an ABX comparator in the system, complete with baling-wire lead to the Yamaha. Zipser improved his score to 5 out of 10. However, my switchpad did develop a hangup problem, meaning that occasionally one had to verify the amplifier in the circuit with a visual confirmation of an LED. Zipser has claimed he scored better prior to the problem, but in fact he only scored 4 out of 6 before any difficulties occurred.

His wife also conducted a 16-trial ABX comparison, using a 30-second phrase of a particular CD for all the trials. In this sequence I sat next to her at the main listening position and performed all the amplifier switching functions according to her verbal commands. She scored 9 out of 16 correct. Later another of Zip's friends scored 4 out of 10 correct. All listening was done with single listeners.

In sum, no matter what you may have heard elsewhere, audio store owner Steve Zipser was unable to tell reliably, based on sound alone, when his $14,000 pair of class A monoblock amplifiers was replaced by a ten-year old Japanese integrated amplifier—in his personal reference system, in his own listening room, using program material selected personally by him as being especially revealing of differences. He failed the test under hardwired no-switching conditions, as well as with a high-resolution fast-comparison switching mode. As I have said before, when the answers aren't shared in advance, "Amps Is Amps" even for the Goldenest of Ears.
Tom Nousaine Cary, IL"

Did you mean 'can' or 'can't'?

I know. I already own that book.

Wow. A Wiki page on the history of the word 'High fidelity'.

Then why did you ask???

me; measurements won't tell the whole story.

arnyk; Please name what specific part of the story they don't tell.

me; Okay, I like upmixing 2ch into 5.1. What measurement would I take with REW that shows the difference in what I hear between the two?

Strange question. We generally don't try to measure what people hear because that would require brain probes or scans.

Furthermore, the usual task is to compare two different facilities for doing the same basic thing.

Usually this kind of operation is evaluated with electrical measurements. REW is usually thought of as acoustics measurement software, and it s not clear that it is ideal for this purpose.

Test signals are applied to each input in rotation and then together and the response to each of these 3 sets of stimuli on each of the 5 channels is measured. Since it is not unusual to use dynamics modification hardware as part of the processing from 2 to many channels, the measurements would have to be repeated over a range of levels. For each test level and channel configuration one would perform frequency response and dynamic range (nonlinear distortion and noise) evaluations.

There are a number of standards for doing this kind of processing, and a key piece of information is which of them is supposedly being adhered to. The most likely would probably be Dolby Pro Logic. The "Pro Logic" is where the dynamics modifications come in.

Interesting question. The usual fault is that the speaker in some sense controls (or causes faulty operation of) the amplifier at higher power levels.

In historical audiophile parlance, speaker control usually refers to damping factor which in turn is a code phase for amplifier source impedance.

An amplifier that has good control over the speaker maintains a low source impedance over the range of operational parameters or combinations of power levels and frequencies that are actually used.

Amplifier source impedance was and remains a big issue for tubed amplifiers, particularly SETs.

I see no properly-labelled references or quotes, so all we have is a paraphrase of a paraphrase of a paraphrase....

Supposing that fidelity refers to any differences a person could hear between a live performance and the reproduction, you're leaving out lots of stuff. Microphones, acoustics of the listening room, geometry of the ear, .... It's obviously not true that changes to the signal other than amplitude changes will "damage the sound". Many changes will not be audible at all. And it's easy to imagine that some changes might improve fidelity -- e.g., equalization to compensate for peculiarities of the speakers or the listening room.

The ears would be the same no matter if it's at home or somewhere else.

There's lots of music that does not have a live performance or that has been touched by a microphone. You cannot put compensations for such on them, it will just be wrong every time.

There is no known live performance state for recordings. They have all been changed in different ways before ending up on the recording. That's the work of art, not the live performance that was one part of creating it. You're just fooling yourself if you strive for that. You can only do it if you pick ONE recording after finding out exactly how it was produced. So if you listen to more than one piece of music, you need one system/room for each.

There is no common flaw to compensate for that applies to all, or even a majority, recordings.

Who cares if it's audible or not when discussing theory? It still damages the sound even if it doesn't damage what you hear.

Also, doing adjustments in electronics for individual setups is uninteresting - it won't scale to other people's setups and when you design an amp, you don't do just one for GregLee's room/speaker combo.
Besides... you might change speakers or move... how good will that coloration be then?

I think this is quite an important point, and one I've been making for awhile. The "golden ears" debate as to whether high price tube and moving coil equipment can be differentiated from accurate lower cost SS (likely) or very high priced SS vs lower priced quality stuff (not so likely) is not the essence of the issue. The question is rather, if the tube sound for example, is preferred, can it be duplicated by adjustments to lower cost quality SS? If it can, then the path forward is clear: create the sound you like with reasonably priced equipment.

Although I'm not immune from typos, in this case I did mean what was written. But wasn't that clear from the context in the preceding paragraph?

Did you simply not believe the answer I gave, or was it not explained to your satisfaction? I'm not sure what your point is.

That's what I'm wondering too.

There is more to hi fi reproduction of sound than amp design, right? You've probably heard of receivers with calibration systems that go to some pains to accomplish what you proclaim to be uninteresting. That's what I began by complaining about: your attempt to substitute a concern about amp design, having to do merely with reproduction of electrical signals, for hi fi reproduction of sound. It's not about electrical signals, though I'm sure they're fascinating in their way.

It's been out there all this time, for you to study.

Keep this in mind: http://www.avsforum.com/t/1425262/are-audio-companies-all-involved-in-a-huge-conspiracy/1530#post_23038613

Never stated as much, you've been reading my posts badly if that's what you've gotten out of them.
. Quite the contrary, I've been saying that the prime concern is mating speakers and room.

Digital compensations in receivers is a ("bad") way to alleviate the problem. The better solution is to put the right speakers in your room, adjust the rooms acoustics to the speakers or most likely a combination of both.

It's all in here : http://tom-morrow-land.com/tests/ampchall/index.htm

It's all in there but you misinterpreted them. Not all amps sound same because some amps are designed to not have "flat" response. When setting up for ABX, the levels need to be matched otherwise the listeners will be subjected to different SPL and end up thinking that it's due to different sound quality even though it's just a difference in voltage of signal.

I understand the level matching part. But EQ'ing the response to be identical? Who would operate their amplifiers in a real world condition like that?