That’d be another step in the right direction.
A bigger, better, and much less realistic one (for most people), is to have neither party know what devices are under test at all. It is not sufficient to simply be unaware of which you are hearing at any given time. And the possibility must exist that your A/B comparison is of the same unit in both A and B cases (i.e. no switch occurred). Without specialist equipment, that usually means having multiple of each unit under test.
I already know what devices are under test, so I can not help that.
But I can hide the devices from my mate. I could put a blanked over the audio setup and just let him have the switcher.
Yeah I know. Thank you for the tips.
For me, this post is about making amp comparisons more fairly and it’s for audiophiles, who may not have all those specialized equipments at hand.
At first, I wasn’t aware, that precise volume matching can be done so easily, as long as the output impedance of the amps do not audibly affect the frequency response of the headphone.
You just need a multimeter and an online tone generator.
I will update this post with an easy tutorial on volume matching for everyone, because volume matching is a must for having fairer comparisons.
Sound likes a fun experiment. Unfortunately a picture and your statement doesn’t really prove anything to me.
Could you explain what you did, how you did it, the background of these 3 people, what music you were playing, what was the volume at which you matched at, etc etc?
1.045 Vrms into the Focal Clear Pro at 3 kHz would yield a listening level of >116 dB/SPL. That’s permanent hearing damage in seconds territory … and not very useful for detecting any kind of difference … ever again.
Did you measure levels with the load (headphones) connected?
No, I wasnt using my headphones for volume matching haha That would be destorying my precious focal clear. I used this cable here and plugged it into the amplifier. And then I just used the other end of the cable to measure the volts. I am going to create a volume matching guide in the next days anyways. Its super easy. [quote=“nhatlam96, post:43, topic:9650”]
I will update this post with an easy tutorial on volume matching for everyone
[/quote]
Unless the amplifiers have the same output impedance, that won’t result in levels matched from the headphone. And it’ll still be north of 115 dB/SPL.
Something is not right there …
I dont understand where the problem is.
amp output impedance: SP200: 1.3ohm and V200: 0.06ohm.
1.3 ohm is already incredibly low.
About those 115 db/spl, I just had my windows audio on 50%
EDIT: ohhh I get it now. Yeah during the volume matching I had it on 100%. After that I set it back to 50%, that is my standard value
Oh, that’s not the only problem.
It’s too long winded to explain if you don’t already have the basic electronic theory down, but the easiest way to fix it is to do the level matching with the headphones as part of the circuit.
A bigger issue for listening is using 50% digital attenuation via the Windows built-in mixer. You’ve got amps in the chain … so you should have that at 100% and use a lower setting on the amplifier (may not be possible if you have an SP200 with the linear pot, but that’s a problem with the amplifier).
Hm, yeah I dont know. But anyways, switching between the amps was like not switching at all. volume stayed the same, tonality, sound, everything.
Well that’s as may be, but it’s not a properly level matched comparison if you didn’t have the headphones in-circuit when you did a meter-based matching (would be fine if the amps had the same OI, but they don’t).
So I would suggest not writing up any guides on level-matching until you know how to do it properly. Not trying to be spiky, but also don’t have the inclination to write it all up and explain it step by step when the information is already available elsewhere.
Hm, I will still do it. I think its good enough. It worked wonderfully for me. No differences in everything
I’ll make this my last comment on this …
I fail to see the point in writing up a guide on the wrong way to do something. There are more than enough “objective” types doing just that, and propagating bad information, as it is.
Bizarre …
wrong way? its not wrong. both amps clearly had the same volume. switching between them was indistinguishable
“I’m ok with doing things wrong in the name of convenience.” ~ No respectable scientist, ever.
I’m going to agree with Torq, not to take sides in the matter, but because I believe there are clearly steps that should be taken to achieve accurate results. Steps that I don’t believe you’re doing. Torq is right. If you put a different load on a circuit, behavior and values of the system will change. It’s literally that simple.
I will just write my guide, and then have you guys check it again.
Its also very simple, that switching between the amps was indistinguishable.
edit: sorry for the wording. was kinda upset. I swear, we all 3 guys did not hear a difference
I believe that you believe that. I also believe that I can’t refute it, because I wasn’t one of those three guys. So all I’m left to go on are your methods.
It’s not personal.
Volume match SP200 and V200:
That’s it. I basically matched the output voltage of the amplifiers. I did not have to worry about the output impedance here, because of the following reasons:
SP200: 1.3 Ohm.
V200: 0.06 Ohm.
Both values do not audibly impact the headphone, because those values are very low.
The ohm impedance values have to be a lot higher to have an audible impact.
Here you can see the Focal Clear (which is the headphone used in this test) driven by 120 Ohm source.
Another example with Focal Utopia.
HD599 and HD800 with different ohm impedances.
As you can see, something like 10ohm is needed to maybe have 1dB impact.
That’s why 1.3 ohm is humanly audibly indistinguishable to 0.06 ohm.
Both amps sounded exactly the same on this method, I dont know what to do anything else besides this point.
