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Posted By: AAAA AVR vs Seprerate- Measured - 09/23/15 11:01 PM
Is it possible amps sound different? Frequency response measurements say maybe.... Or do they?

To be fair, this is a garbage test, including subs not recalibrated between amps. The gain between the amps is slightly different, so the bass in the room slightly differs between tests. Could this be why people perceive a "fuller" sound between amps? Or is there enough variability above the crossover frequency (60hz plus rolloff in this case) to call differences audible. You decide. smile

The 2ch amp needs a 1.5db boost in the preout settings to match the AVR's internal amp gain I'm guessing, but we're in the ballpark anyway.

2ch amp- 1/12 octave pink noise averaged



Posted By: AAAA Re: AVR vs Sererate- Measured - 09/23/15 11:02 PM
AVR - 1/12 octave pink noise averaged

Posted By: craigsub Re: AVR vs Separate- Measured - 09/24/15 12:16 AM
Without more sweeps being run, and blind tests conducted between the two, it's pretty much impossible to make any substantive observations on the two graphs. The general shapes are comparable, and the smoothing applied plus other factors (air movement in the room, slight change in microphone position, etc ... ) are unknowns.

Researching and asking are good things, though. smile
Posted By: AAAA Re: AVR vs Separate- Measured - 09/24/15 09:21 AM
I thought the graphs would be the same. Slight variations can be seen between 1-4khz. There is more of a tilting into the valley trend with the AVR and a bump right before 2khz. May be nothing.

I dont test using sweeps most of the time, the reason is as you stated, variability. I run pink noise and set the FFT to average the spl per frequency over time. I give it 30 seconds or so, but usually the graph has fully stabilized by the 7-10 second mark.

I use 1/12 octave resolution (twice what we are thought to be able to hear) because 1/3 or even 1/6 resolution can hide narrow high Q problems. Not that we are very good at hearing those either. smile

As a curiosity, sighted, I preferred the sound at first of the AVR over the power amp..... Once I started to turn it up however, the Amp remained sounding composed while the AVR started to sound brassy. Its hard to describe, but guitars start to sound more twangy with the AVR at higher volumes. Audible distortion perhaps? I would have never noticed it without a comparison like this.

I could be imagining things. I should re-run the measurements at a higher db and see.

I used the track "Timshel" from Mumford and Sons album Sigh No More for testing.
Posted By: AAAA Re: AVR vs Seprerate- Measured - 11/22/15 04:50 PM
I've been watching/listening to a lot of content lately with my father in law. He is a little older than me and his listening volume preference is a little higher than mine. I would say my average level is somewhere around 60-65db avg while his is 70-75 db avg.

Anyway, I have started to notice brief moments when listening to concerts and the lotr: two towers with him that my AVR was sounding a little strained.

My room is pretty much treated now and I've lived with it long enough to be pretty keen on subtle changes. It is not hard to hear when channel levels are out of whack even a couple db now and it is pretty easy to hear differences in balance when the sub levels are adjusted by a single db in the AVR setup menu. shocked

As a bit of a test I hooked up my 2ch power amp. I'm still waiting to get it properly integrated into my system. Stupid proptrietary gear! mad I reset the trim levels for the preouts to match the spl of the other channels (75dba) and sat for a listen to some Daft Punk -RAM.

AMPS DO SOUND DIFFERENT. Or do they?

It sounded like a step backwards. I preferred the sound of my AVR I had just bypassed...... What?! I tried to think why as I clicked through tracks and it dawned on me. The towers were now producing bass at levels that were enough of a change to throw out the sub/speaker balance. I turned the sub trim down by 1db. Yes, 1db, and everything fell right back into place.

1db. Wtf. Audio is a strange game.

The amplifier is capable of much more current vs the AVR at any listening level and the entire power balance had shifted towards slightly more bass. Not a ton, but enough I could notice the fingering on guitars in "get lucky" was being masked by what I perceived as bass a little proud of the balance I had.

After the slight adjustment, the balance now sounds right again, and it is indistinguishable from the old setup to my ears.

1db.

I can now listen at any volume and the pitch of the track doesnt shift with loudness, as it did with the AVR. There is no more "brassyness" or hardness at loudish listening levels. I have a few tracks I crank and listen to to relax. I really like Enya's Caribbean Blue loud. So euphoric. I always thought the track had been mixed so the first couple loud tones in the song had a pronounced peakiness or attack to them. They aren't supposed to. My AVR was adding distortion once I poured the volume on. Not at agressive levels either.... Like 80db or so.

Food for thought if nothing else.
Posted By: AAAA Re: AVR vs Seprerate- Measured - 12/12/15 10:57 AM
For anyone interested, I'm trying to get a technical explanation of why the response of the 2 setups differed over at AVS.

If you wanna see me get beat up soon here you go! grin

http://www.avsforum.com/forum/91-audio-t...nt-mention.html
Posted By: chesseroo Re: AVR vs Seprerate- Measured - 12/12/15 03:43 PM
Originally Posted By Serenity_Now

1db. Wtf. Audio is a strange game.

And in no small way, because the "mind plays tricks..."

As Craig inferred, this is always fun to do for the sake of fun, but realistically, one requires a very controlled setup to determine the most valid results.
It has long been published in science literature that human audio memory is very short. Without an instantaneous switching method the observations anyone makes (and believes are real) are subject to bias. It doesn't matter if a person had a 20 year musician in the room, or their wife who never heard the setup the first time, etc. etc.

All that being said, and taking Craig's comments re: room atmosphere alone into account, the two graphs produced are EXTREMELY similar (overlay the two and you will see how little difference exists; anything at delta 1dB for a minor frequency range would not likely be audible). If repeated and averages over multiple trials, i would doubt there would be any statistically significant differences in those curves and for the most part, that was already demonstrated for most of that spectrum reproduction.

The suggestion that the AVR is being strained in its power output is certainly plausible depending on the playback SPL and speakers being driven. I have found our AVR to have a change in sound as SPL increases much earlier than i ever expected, though the point at which i "perceive" that to be happening is still pretty loud (>85 dB at 11 feet).
Posted By: chesseroo Re: AVR vs Seprerate- Measured - 12/12/15 04:02 PM
BTW, that's a nice looking amp!

Posted By: chesseroo Re: AVR vs Seprerate- Measured - 12/12/15 04:10 PM
Originally Posted By Serenity_Now

If you wanna see me get beat up soon here you go! grin

I haven't ventured over there in years b/c of the idiots that exist in droves, but surprisingly you've got a few decent responses so far that hearing damage at high (and clipped) SPL, as well as noting importance of DBT (double blind tests). I didn't think anyone over there supported such a logical notion.

I think i'll stop looking at the thread while it still remains civil.
Posted By: MMM Re: AVR vs Seprerate- Measured - 12/12/15 07:28 PM
I am in the midst of changing out my equipment.

As this thread is about separate components, I figure that I would chime in about my experience. I personally found that my Pioneer AV receiver doesn't produce as pleasing a sound as my older Yamaha amp. I think that has something to do with the Yamaha has an older A/B design amp with a sizably large transformer. Where the Pioneer has moved to a more efficient Class D amp bit it just doesn't have what it takes to power a 4ohm speaker.

I have an Anthem that is a large Toroidal Transformer with it's Class A/B amp and produces a warm sound that is very enjoyable. Rated at 200w @ 8ohm, I am told it is stable down to 2ohm.

I have pulled the Anthem from my rack and started using the AudioSource One/A amp. This is an 80w @ 8ohm and is supposed to be stable down to 2ohms as well. I have a pair and use them to drive my LFR1100 speakers, but find the sound is not as pleasing as what I got from my Anthem amp. it just doesn't feel as warm and at volume feels a bit more lacking. I don't know if it's the design of the amp or the 120w less power in the unit. There would also be less current capacity inside the amp.

All un-scientific view based on sighted tests. It's not that I have some opinion one way or another that something should sound better so it does. I don't know.
Posted By: AAAA Re: AVR vs Seprerate- Measured - 12/12/15 07:44 PM
Someone at AVS came up with an idea of how the differences in the low frequency response was being created. They were preout signal related. When I boosted the preout levels of the 2 mains to match the other channels I was also unintentionally boosting the output to the subs below the sub crossover frequency. With stereo content this resulted in an increase of about 2db below 100hz, and was audible but subtle.

Here are the new graphs. They are virtually identical once the subs are out of the equation by removing it in the AVR settings.

R\L channels powered by AVR. 1/12 octave averaged pink noise. 5db divisions. Towers ran full range, no sub.



R\L channels powered by Seperate amplifier. 1/12 octave averaged pink noise. 5db divisions. Towers ran full range, no sub.



Matt, I still think it is genuinely possible for amps to make a difference in sound quality. I think it has more to do with the ability to play without distortion or tonal shift as spl increases. As for frequency response, both these amplifiers measure the same so far as the graphs show at a pink noise output of 75db.
Posted By: chesseroo Re: AVR vs Seprerate- Measured - 12/13/15 06:25 AM
Originally Posted By oakvillematt
All un-scientific view based on sighted tests. It's not that I have some opinion one way or another that something should sound better so it does. I don't know.

And as a scientist i can appreciate that some people don't seek a proven truth when it comes to this hobby.
Sometimes the magic is in looking at a new piece of gear and thinking you are creating something cool and amazing sounding.

I personally like to shop for different amps even though i am generally in the camp of "all properly designed amps sound the same". I just like the aesthetics of the some of the pricier options.
I hate black.
It is just some cool ass gear to look at while listening to good music.
Posted By: chesseroo Re: AVR vs Seprerate- Measured - 12/13/15 06:34 AM
Originally Posted By Serenity_Now
I still think it is genuinely possible for amps to make a difference in sound quality. I think it has more to do with the ability to play without distortion or tonal shift as spl increases. As for frequency response, both these amplifiers measure the same so far as the graphs show at a pink noise output of 75db.

There would have to be a technical difference for amps to sound difference such as SPL out of the range of the amp specs (e.g. distortion) or a specific reason why some limitation was applied to an amp that may change the sound (e.g. some kind of filter or super thin internal wiring, etc.).
Otherwise within specs, all amps should be designed to produce the most accurate sound which is to say in a frequency sweep the amp produces nothing but a ruler flat line.
This is most common in virtually any measurement i've seen from competent SS amp builders.

I have a friend who for the longest time was a stereophile. Collects vintage gear for decades now and knows his electronics specs! Was always a stalwart believer in amps sounding different until his guru electronics friend built an instantaneous switcher and they did some playing around with different amps in A/B testing.
Now admittedly if there are differences between amps, they are so small that they are virtually unnoticeable. SPL still needs to be applied which their switcher does not do, and as such, by eliminating that last piece of the variables, the nonconvertible may have been converted simply by doing a more controlled test.

Is the magic gone?
Maybe a little.
But they still like the bling and being able to crank up a 500W /ch amp to its max!
There's always still fun to be had.
Posted By: AAAA Re: AVR vs Seprerate- Measured - 12/13/15 11:21 AM
Chess, the more I learn about all this stuff, by reading and measuring and pondering, the more I have to say I agree with you.

I'm starting to view SS amps less as audio gear, and more as lab gear. The differences originally measured and heard were due to my user error. Dang preout settings!
Posted By: BobKay Re: AVR vs Seprerate- Measured - 12/14/15 04:38 PM
Originally Posted By chesseroo

Is the magic gone?


Spoken exactly like a scientist, an evil scientist.

You dastardly demon!

Never!

My first record player was a small, vinyl-covered pressboard box. It played only 78's. As children's recordings, they were made in bright (bilious) yellow, They had an LP-sized hole in the center.

When I wanted to play and sing along with the theme from "The Jetsons," I turned a knob that started the table turning with my selection positioned on it. I gently placed the 17 oz. plastic "tone arm" down on the lead-in slips. I'd watch and wait for the needle (which was no more than the nail-end of a pencil compass) to be drawn into the first groove. Then the magic started.

As the nail became ever-more sophisticated, then so did The Jetsons. Now the nail was a "stylus," tipped with really expensive shit. The Jetsons became The Beatles and the process never stopped, like most things in the modern world.

How a nail on a piece of plastic with grooves (OK, one groove) cut (OK, pressed) into it, could play drums and pianos and trumpets and strings and people singing through a speaker(s), was stupefying.

Still the best magic trick I've ever seen (with eyes wide shut)!

The Jetsons B-side? The B-side was a rockin' little diddy sung by the Judy character's voice over artist. It was called "Oop, Eek, Orc, Ah-Ah, Than Means You're the End." When I say "little diddy" I mean it. That title was the entire chorus. Bite me, Katy Perry.

And now the magic is even more real and louder and bigger; much, much louder, and much, much bigger.

If the magic goes with me, and only me, then so be it.

Come to think about it, this Forum is entirely for seeing images, writing and reading ABOUT hearing. Move along, folks, there's nothing to hear, here.

Do not look at that man behind the curtain! Stop looking! When you close your eyes, it IS magic. Where else does size matter so much only with your eyes closed? If that's not magic...


(Oh, that collection of about 100 78's with original sleeves? Umm, when we had graduated to lp's, we used them for Frisbee toss/brick wall games. The ones that didn't "make it" were gathered up, then we'd move the throw-line about 6 feet (2m) closer each time. As it turns out, it's a rather quick process.)
Posted By: fredk Re: AVR vs Seprerate- Measured - 12/15/15 03:09 PM
Originally Posted By chesseroo
Is the magic gone?

Nah. Maybe science has let the magic smoke out of that black box known as an amplifier, but pot legalization has doubled down and injected the smoke directly into the listener. grin

Of course the real magic still resides where it always has. With the composer.
Posted By: SBrown Re: AVR vs Seprerate- Measured - 12/15/15 11:24 PM

[/quote]


Is the magic gone?

[/quote]

Nope!

https://www.facebook.com/AxiomAudio/phot...3177446/?type=3
Posted By: AAAA Re: AVR vs Seprerate- Measured - 12/16/15 01:13 AM
You bet there is more fun to be had! where's my calculator! grin

Hopefully this nerdy stuff I do spares you guys from doing it yourselves. It is fun though.
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