Easiest way to volume match during a A/B comparison?

@money4me247
 
I may be able to shed some light on what I use. As castleofargh said, it can be a nightmare if you're using headphones with highly contrasting frequency responses, but it's not too bad if you're trying to compare headphones with roughly similar responses.
 
I use constant test tones - 300 Hz, 1 kHz and 3 kHz.  For most of my comparisons, I tend to use the 3 kHz one the most, as it's where the vocals are often most prominent, and my own listening tends to be striving to have vocals matched - then comparing other parts of frequency response in relation to vocals.
 
For an spl meter, I use an iPhone5S, and an spl app.  It's only supposedly accurate to 1dB, and I have no way of calibrating it, or checking it, but I have noticed that it is very consistent in in its measurements.  The main aim for me when doing this is simply to stop volume matching "by ear" as I know my own ears are not as accurate as the meter.  And for reviewing - I clearly state that my reviews are purely subjective, but using the volume matching is my attempt to at least be more accurate in interpreting my own subjective observances.
 
If I'm doing full sized headphones, and the cup sizes are similar, I'll take some foam, shape it to the cups, cut a slit for the 5S, and then position the whole set-up so the 5S is as close as I can get to being consistently placed relative to the driver (I measure against 1 driver each time).  This often involves aligning the S5 adjacent to a screw or mark on the yolk, so I can get consistency.  It's really important to have the mics the same distance from the drivers - so you have to play with this to get it as close as you can.
 
Then I run the app, take the measurements, but more importantly, take multiple instances.  As long as the measurements are showing consistency, I note the volume on the pot on my amp (or DAP - the X5's digital control can be very handy).  Next I compare using actual music with the measurements I've taken (IE adjusting the pot to what I've worked out is a volume match @ 3 kHz).  If they sound the same to me - I then repeat the tone test (measuring again) to make sure it's still consistent.
 
Once I'm fully satisfied - I then do my comparisons, and make my notes.
 
I full recognise that the system I use has a lot of room for inaccuracy - but it's as good as I can get it without spending hundreds of dollars.  I also have a similar setup for IEMs.
 
Hope that helps.  It was invaluable for me doing my DT880 and T1 comparison and is proving to be very helpful with the HD600 vs HD650 exercise I'm embarking on now.
 
Cheers
 
Paul

to set the volume I use the crappy mic on my lowfi "gaming" headphone into my laptop and run the RMAA calibration stuff(recording only) while playing a tone.
I'm not sure how precise it really is but it shows 0.1db values.

Does it really matter?
 
After all, the purpose of ABX testing is not to demonstrate one product is objectively 'better' than another. Not even to help decide which one might prefer.
 
It is to prove that the subject can reliably tell them apart by ear alone. It's not the same situation as testing something like cables, amplifiers or DAC implementations where people sometimes make outrageous claims they are unable to replicate in an unsighted test. Pretty much everyone agrees different  headphones (and speakers) sound different as a matter of course.
 
So, proved you have sufficient gain there is no issue with testers making volume adjustments or whatever. You test for preference. ABX does not really help detect FR abnormalities, noise, timing errors or distortion. You you have no real need to level match except to be able to say that with the same input the two items under test are distinguishable from one another. It's useless to method to prove absolute superiority.

@RonaldDumsfeld
 
I think maybe you're not understanding what the OP is asking.  He's not inquiring about setting up an ABX.  He's asking about volume matching two headphones, so he can then do a sighted but subjective review and comparison.  There is no need for ABX in this instance.

But why? What would it prove?
 
Provided he puts the same signal through both headphones he has the basis for a comparison. In fact he doesn't even need to do that.

He's not trying to "prove" anything.  He's trying to subjectively compare 2 different headphones, and trying to remove the variable of differing volumes creating the impression that the louder one is better.
 
The problem is in his title for this thread.  He's talking about an A/B test.  Not an ABX.

ronalddumsfeld said:

  But why? What would it prove?
 
Provided he puts the same signal through both headphones he has the basis for a comparison. In fact he doesn't even need to do that.

Click to expand...

 
And to answer the bit in red -  I did the same exercise comparing a T1 to a DT880.  Very similar frequency response, but very different impedance and sensitivity.  So to do a comparison (subjective), it's necessary to first remove volume mismatch before A/Bing them.

Originally Posted by Brooko /img/forum/go_quote.gif
 

ronalddumsfeld said:

  But why? What would it prove?
 
Provided he puts the same signal through both headphones he has the basis for a comparison. In fact he doesn't even need to do that.

Click to expand...

 
He's not trying to "prove" anything.  He's trying to subjectively compare 2 different headphones, and trying to remove the variable of differing volumes creating the impression that the louder one is better.
 
The problem is in his title for this thread.  He's talking about an A/B test.  Not an ABX.

Click to expand...

 
hahah you guys are absolutely right. I mistyped my thread title. I am not trying to do an ABx test actually. Just an A-B comparison. Not really trying to prove anything. Just want to see what kind of sonic differences I can notice while the volumes are matched.
 
Sorry for the confusion & thanks for the feedback!

money4me247 said:

  lol..... so basically no way to accurately compare headphones & remove volume bias?
 
*whole head-fi website made irrelevant* hahaha

Click to expand...

 
If the earphone is for personal use, just find a volume you prefer to use each at and decide which you prefer. It's not a test for posterity. If you don't have a clear preference, buy the cheaper one or the one you listened to at a lower volume. If you want to be more critical, purposely slightly reduce the volume of one and then the other in comparisons and see if it changes your opinion.