Master Thread: Are Measurements Everything or Nothing?

[j_j]

Calories?! It’s only 5!

JUST ONE WAFER THIN MINT?

 

[nugget]

Calories?! It’s only 5!

120 calories is a lot.

 

[MattHooper]

Erin just put up I think one of his best ever videos, though as of yet it’s only in his Patreon section I believe. Therefore, I won’t spill too many beans.

But essentially he used the - admittedly, he says Clickbait title - “ synergy is real”

His video is about how amplifiers can sound different, depending on the amplifier and speaker load. It was occasioned by his both measuring and doing blind tests of a recent Prima Luna two amplifier versus a Macintosh 275 amp, and he was very surprised at both the obviously Audible difference as well as the measured difference, which he shows in the graphs. He then goes on to explain the interactions of output impedance in amplifiers with regard to loudspeakers, using various loudspeaker loads to show the variations and frequency response if you’re using an amplifier with high output impudence like the Prima Luna, and he shows some great graphs with tons of different loudspeakers and how their impedance loads would interact.

I mentioning this for anybody who would be interested to check out. Link to his post about it:

Post from Erin's Audio Corner

Amps sound different. There. I said it. (link to video on patreon below) https://www.patreon.com/posts/amplifier-and-135183029?utm_medium=clipboard_copy&utm_...

youtube.com

I hope he makes the video public because it’s so well done and informative.

 

[goryu]

His video is about how amplifiers can sound different, depending on the amplifier and speaker load.

I would have thought that rather obvious when combining amplifiers with load dependent frequency response and speakers with widely varying impedance with frequency.

 

[voodooless]

Both of these amp have a poor damping factor. Of course they influence the frequency response.

Nothing but clickbait nonsense.

 

[MattHooper]

I would have thought that rather obvious when combining amplifiers with load dependent frequency response and speakers with widely varying impedance with frequency.

You’d think, but there are other ASR members who seem to put even tube amplifier sonic differences in the mostly imaginary bin. (when I have brought up my tube amps sounding different from solid state I’ve seen two camps of replies here - one camp saying “ well obviously” and the other camp saying “believing your tube amp sounds different from the solid state amps is more likely due to sighted bias.”

Both of these amp have a poor damping factor. Of course they influence the frequency response.

Erin says the McIntosh amp “ behaves quite well in terms of output impedance” (which is one reason why he did the comparison between the McIntosh and the prima Luna amp, showing how much the prima Luna amp with it’s much higher output, impedance deviated from the McIntosh) .

Nothing but clickbait nonsense.

Maybe it’s worth looking at the video before writing it off?

As I said, I think it’s a very well done and extremely informative about the how amplifiers, both solid state and tube, can interact with different speaker loads. It might not educate you, but I wouldn’t brush off the fact it’s likely to educate plenty of other people.

As to the synergy thing… that actually does fall out of what Erin explains. It is quite possible to have “ synergy” in terms of how amplifier (for instance in amplifier with high impedance output) interacts with a given speaker. As Erin takes pains to point out though, that doesn’t mean he’s recommending you go out and start using amplifiers as tone controls, given how hit and miss and unpredictable that search would be.

 

[voodooless]

Erin says the McIntosh amp “ behaves quite well in terms of output impedance” (which is one reason why he did the comparison between the McIntosh and the prima Luna amp, showing how much the prima Luna amp with it’s much higher output, impedance deviated from the McIntosh) .

The 275 has a damping factor of 14. That is still poor.

Anyway, why prove your point with two tube amps? That’s just silly. They are just used to manufacture an issue that properly functioning amps reduce to the inaudible.

 

[MattHooper]

The 275 has a damping factor of 14. That is still poor.

FWIW, Erin said the McIntosh’s impedance is .10ohms “ with only a slight deviation above 10kHz” (but that he needed to doublecheck that to make sure).

I don’t know enough to understand how that interacts with your claim.

Anyway, why prove your point with two tube amps?

Because one of them in particular provided an excellent example of how an amplifier impedance can interact audibly with speaker impedance. Why would he prove his point a solid state amplifier that doesn’t do so when he had a real world amplifier on hand that was a perfect example of the principal he was trying to explain???

He included solid state amplification examples as well showing how they can keep a steady impedance against which to show the deviations of the tube amplifiers.

That makes sense if you’re trying to make the point about how amplifier impedance matters.

They are just used to manufacture an issue that properly functioning amps reduce to the inaudible.

Sure, you wouldn’t use a tube amplifier I’m presuming, but plenty of them are made and sold, and they also have a reputation for sounding different from solid state, so Erin’s video is a helpful explanation for how it is certain amplifiers can change the sound coming from your speakers.

I don’t understand your beef. Erin is doing excellent audio education. Not sure why it needs to be greeted so dismissively . But I guess I can’t convince you out of it.

 

[voodooless]

Erin is doing excellent audio education. Not sure why it needs to be greeted so dismissively . But I guess I can’t convince you out of it.

With that kind of a clickbait title, you’ll get my clickbait response… it’s as simple as that. I’m sure his data is correct, and his conclusions are somewhat nuanced. But frankly, there is nothing new here, and it will just strengthen some people’s beliefs that all amps sound different.

 

[mike70]

i think Erin and @MattHooper intention is very valuable ... the relationship between amplifiers and speakers is ruled by science, it's not magic.
A decent engineered amplifier (modern or vintage) will be transparent to the speaker load, but some of them aren't ... even costing thousands.

So, you will play a roulette game with your speakers until you find the "magic sauce" or you will use a good amp and then add some EQ if you want?
Thousands vs EQ via software / integrated in today preamps.

I mean, a very good discussion ... not a source of discrepancy.
Repeating "amplifiers sounds the same" is more like a mantra than science ... that stuff have some knowledge to understand, not a religious belief.

 

[rdenney]

If the output impedance of the McIntosh amp is 0.1 Ohms (I'm just repeating what Matt claimed above and taking it at face value), and the speakers are 8 Ohms, the damping factor is 8 / 0.1 = 80. Which is not "poor". If the impedance of the speakers is 2 Ohms, the damping factor will be 20, which might still be okay. But the traditional McIntosh amps were not designed for near-short speakers even if they can survive them. Back in those days, 16-Ohm speakers were not at all rare, and some of those vintage tube amps that attract so much interest aren't as robust as the typical McIntosh.

(Of course, those aren't the differences people claim that get roundly challenged at ASR--the dispute here isn't about tube amps of ancient design intended for 16-Ohm speakers being asked to drive speakers with 2-Ohm dips, but rather modern amps with slivers of output impedance--my Hypex NC502MP has an output impedance of 0.0015 Ohms except in the top octave--that exhibit damping factors one or two orders of magnitude higher than that McIntosh.)

Rick "suspecting most people who hear differences should be careful about coupling modern low-impedance speakers with vintage high-output-impedance amps" Denney

 

[MattHooper]

So, you will play a roulette game with your speakers until you find the "magic sauce" or you will use a good amp and then add some EQ if you want?
Thousands vs EQ via software / integrated in today preamps.

That’s just taking the fun out of

Personally, it didn’t take me long, playing the roulette game to win. The first combination I ever used was a CJ MV55 tube amp with Quad 63s and I found the sound to be glorious. The next tube amp I bought - more powerful when I moved to new speakers - I’ve kept ever since for about 25 years now.
It’s sounded great with every loudspeaker I’ve owned.

 

[atmasphere]

Both of these amp have a poor damping factor. Of course they influence the frequency response.

Nothing but clickbait nonsense.

FWIW Dept: Mac and EV lead the charge during the 1950s for using Voltage drive rules in loudspeakers, the idea being using an amp that behaves as a Voltage source driving the speaker (the goal being better 'plug and play' with less adjustments needed). Its no surprise the Mac 275 is perfectly capable of this behavior as its output impedance is actually pretty low due to sufficient feedback. I suspect the Prima Luna is not.

Also FWIW no speaker made needs a damping factor over 20... (this coming from the head engineer at EV).

 

[levimax]

If you want to see what your speakers would sound like with a tube amp you can add resistance between the amp and speakers to simulate higher output impedance. You can use 1 ohm for a standard "push pull Ultra linear design" or 5 ohms for a low feedback 300B SET or match the resistance to the amp you are interested in. I have tried it and it "works" in that you can easily measure the difference in FR at the speakers. Tube amp fans hate this idea because it deflates their ideas about "tube magic" and "tube sound" but since FR is the thing we are most sensitive to, output impedance and FR changes are going to be more audible than other alleged "tube magic" like 2nd order distortion or soft clipping.

 

[goryu]

As is usually the case, there are different kinds of audio enthusiasts: those who couldn't care less about optimizing the engineered performance of their audio system (i.e., use equipment with state of the art measured performance, take care to match components based on performance parameters to optimize synergy, etc., then listen- the "intelligent design" approach) and instead just select and match components based solely on their subjective impressions with little or no regard to the actual performance of the equipment, alone or as part of a system- the "sounds great to me" approach. Some tend to overthink it through their enjoyment of the intellectual exercise that is engineering, others prefer "ignorance is bliss"...

 

[Petrushka]

I’m afraid I’m the worst. I just buy the best things I can afford that test well, install them where they fit in the room, and learn to live with it.

 

[levimax]

I’m afraid I’m the worst. I just buy the best things I can afford that test well, install them where they fit in the room, and learn to live with it.

Human's ability to "hear through the room" is sometimes overlooked with the easy availability of measurements and graphs and DSP. A good measuring speaker with transparent electronics (easy unless you go out of your way to find something broken) is going to sound good in most rooms. That doesn't mean that the measured sound isn't negatively affected by the room or that it couldn't be improved with placement, treatment, or DSP but rather our brains do a lot of work filtering out room effects. Whenever I am frustrated with my in room measurements I take a look at the measurement with "psychoacoustic smoothing" or "ERB smoothing" and feel better and then go enjoy listening.

 

[MattHooper]

Whenever I am frustrated with my in room measurements I take a look at the measurement with "psychoacoustic smoothing" or "ERB smoothing" and feel better and then go enjoy listening.

I’m never frustrated with my in room measurements because I don’t take any ;-)

(with the exception of when I briefly had dual subwoofers and DSP).

As much as golden ears may go down their tweaking rabbit holes, it seems one can be dragged down a certain neurotic rabbit hole when it comes to measuring their system, constantly trying to even things out for more perfection.

(not that I’m putting you in that camp… and in any case, whatever turns somebody’s crank is of course fine)

 

[Purité Audio]

I would advise everyone to acoustically measure their system, ‘golden ears’ not required.
Keith

 

[MattHooper]

I would advise everyone to acoustically measure their system, ‘golden ears’ not required.
Keith

As I said: that can be another version of a rabbit hole
;-)

Vast numbers of audiophiles are happy with their systems without going to the length of measuring their systems.