[reddog]

measurement results above were extremely similar to my own findings. will post my measurements soon in my initial beta unit review.

Looking forward to your review.

 

[DreamKing]

Thanks for this, it appears that going by Tyll's measurements, the HE-1000 is less efficient then what is generally thought. Is this more true than going by Hifiman's specs that lead to believe 1W is enough for 120dB SPL?
 
Quote:

Spoiler: measurements

  Looks like Tyll measured a HE1000 unit.
http://www.innerfidelity.com/images/HiFiMANHE1000PreProduction.pdf

I've added on the diffuse-field HRTF and Harman target curves on it.

 

Spoiler: Derived Amplifier/Power Requirements

I used the voltage measurement to reach 90 dB SPL from Innerfidelity to derive all of these.
P = (Vrms^2) / R to derive the power requirements
P = I * Vrms, P / Vrms = I to derive the current requirements


Power increase per 3 dB change in SPL:
For +3 dB SPL change
3 dB = 10 * log_10(P / P0)
P = P0 * 10^(3 dB / 10 dB)
P = P0 * 10^(3/10) = P0 * 1.99526

For -3 dB SPL change
-3 dB = 10 * log_10(P / P0)
P = P0 * 10^(-3 dB / 10 dB)
P = P0 * 10^(-3/10) = P0 * 0.50118



 

dB SPL	mW	W	Vrms	mA
69	0.019	0.000	0.026	0.752
72	0.038	0.000	0.036	1.063
75	0.077	0.000	0.051	1.501
78	0.153	0.000	0.072	2.120
81	0.305	0.000	0.102	2.995
84	0.609	0.001	0.144	4.231
87	1.214	0.001	0.203	5.976
90	2.423	0.002	0.287	8.441
93	4.834	0.005	0.405	11.923
96	9.645	0.010	0.573	16.842
99	19.244	0.019	0.809	23.790
102	38.396	0.038	1.143	33.605
105	76.610	0.077	1.614	47.468
108	152.857	0.153	2.280	67.051
111	304.989	0.305	3.220	94.712
114	608.534	0.609	4.549	133.784
117	1214.185	1.214	6.425	188.974
120	2422.618	2.423	9.076	266.933

Spoiler: Derived Amplifier/Power Requirements

 

 

[goldendarko]

I thought they weren't quite as efficient as specs would indicate. Seem to require a lot of juice for a phone rated at 90

 

[miceblue]

Thanks for this, it appears that going by Tyll's measurements, the HE-1000 is less efficient then what is generally thought. Is this more true than going by Hifiman's specs that lead to believe 1W is enough for 120dB SPL?

I never trust manufacturer's sensitivity specifications since it's usually a general target, which is never absolute. I don't think all X number of HE1000 units will have 90 dB SPL/mW sensitivity, unless they somehow have super precise and super accurate manufacturing methods with very little tolerance values. HIFIMAN is the only company that I know of who lists impedance numbers with a ± value, in this case 35 ± 5 Ω. My HE1000 unit happens to measure at 31 Ω with the 3.5 mm cable when using a simple digital multimeter.

If you look at any of Innerfidelity's measurements, I don't think you'll find a single headphone that meets the same numbers provided by the manufacturer. The closest one is probably the HD800 at 0.963 Vrms to reach 102 dB SPL at a 361 Ω impedance (compared to Sennheiser's specifications of 300 Ω, 102 dB/Vrms).

 

[DreamKing]

I see, I'll remember this. 1W to 2.4W is quite a difference from a general target...

 

[reddog]

I never trust manufacturer's sensitivity specifications since it's usually a general target, which is never absolute. I don't think all X number of HE1000 units will have 90 dB SPL/mW sensitivity, unless they somehow have super precise and super accurate manufacturing methods with very little tolerance values. HIFIMAN is the only company that I know of who lists impedance numbers with a ± value, in this case 35 ± 5 Ω. My HE1000 unit happens to measure at 31 Ω with the 3.5 mm cable when using a simple digital multimeter.

If you look at any of Innerfidelity's measurements, I don't think you'll find a single headphone that meets the same numbers provided by the manufacturer. The closest one is probably the HD800 at 0.963 Vrms to reach 102 dB SPL at a 361 Ω impedance (compared to Sennheiser's specifications of 300 Ω, 102 dB/Vrms).

Well said.

 

[reddog]

I thought they weren't quite as efficient as specs would indicate. Seem to require a lot of juice for a phone rated at 90

I am surprised my fiio e12 could drive the HE1K as well as it did.

 

[daltonlanny]

I wonder what is causing the "saw tooth" irregularities between about 200 hz to 2 khz?
These irregularities were also visible on another frequency response measurement on another site.

 

[miceblue]

I see, I'll remember this. 1W to 2.4W is quite a difference from a general target...

I usually use 105 dB SPL as a high target for me. These calculated values are sustained/average/RMS values, so using 120 dB SPL is a highly unrealistic target unless you want to go deaf.

Why 105 dB SPL as a high target for me? I usually listen to music at about 70-80 dB SPL (average) from what I heard at a local meet with a calibrated audio system. That's nowhere near 105 dB SPL, right? Tack on +25 dB to that to take into account any peaks that occur throughout the music as headroom and you get to 105 dB SPL peaks. That's being generous for me though since pretty much all of my music has a dynamic range of 9-20-ish dB and 25 is a just an over-estimate.

I am surprised my fiio e12 could drive the HE1K as well as it did.

The E12 can output a maximum of 5.3 Vrms and 170 mA. That should be plenty for the HE1000.

 

[rgs9200m]

Did Tyll briefly review or comment about the HE1000 beyond the brief remarks I see on Innerfidelity? If so, could anyone point to it? Thanks.

 

[money4me247]

I wonder what is causing the "saw tooth" irregularities between about 200 hz to 2 khz?
These irregularities were also visible on another frequency response measurement on another site.

I personally have no idea either and experienced the same phenomenon with my initial measurement tests as well. Nearly drove myself crazy trouble-shooting and adjusting my measurement set-up as I did not hear any spikey bumpy changes during my personal frequency response sweeps. I am still not sure what to make of it, but at least I finally figured out that it wasn't me doing something stupid causing it. will post my beta measurements when I get home. not sure if production versions will be different though.

 

[money4me247]

  Did Tyll briefly review or comment about the HE1000 beyond the brief remarks I see on Innerfidelity? If so, could anyone point to it? Thanks.

@rgs9200m, here you go. his brief comments
 
Quote:

HiFiMAN HE-1000 Pre-Production - First I have to say I do enjoy the sound of these headphones—they're fairly neutral, without any harshness, and very inoffensive. But they're also strangely soft in their attack. Not sure where that shows up on the measurements, but I will point out the strangely bumpy frequency response between 200Hz and 2kHz—quite unusual. Also, the somewhat high distortion at 100dBspl, and corresponding (though small and difficult to see) bumps in the impedance response. I'll investigate further when I do the review—and it's worth noting these are one of the pre-production units that are going around right now.  
source: Tyll at http://www.innerfidelity.com/content/innerfidelity-june-2015-update

 
link to full graph: http://www.innerfidelity.com/images/HiFiMANHE1000PreProduction.pdf

 

[DreamKing]

I usually use 105 dB SPL as a high target for me. These calculated values are sustained/average/RMS values, so using 120 dB SPL is a highly unrealistic target.

Why 105 dB SPL as a high target for me? I usually listen to music at about 70-80 dB SPL (average) from what I heard at a local meet with a calibrated audio system. That's nowhere near 105 dB SPL, right? Tack on +25 dB to that to take into account any peaks that occur throughout the music as headroom and you get to 105 dB SPL peaks. That's being generous for me though since pretty much all of my music has a dynamic range of 9-20-ish dB and 25 is a just an over-estimate with some head-room.

 
I'd rather take 120 dB SPL as a target because like you said, these measurements aren't consistent and vary depending on unit. 
 
 Also, I like hefty headroom and having volume control somewhere around the middle rather than on either extreme. So I'd personally prefer an amp that can drive any load at high levels rather than "just enough" for one headphone I happen to be interested in. Sometimes I just listen louder than average volumes based on mood. I have quite a few recordings at more or less 30 dB DR too that don't hit those peaks consistently enough to damage hearing, when I compensate for the generally lower volume playing.

 

[miceblue]

I'd rather take 120 dB SPL as a target because like you said, these measurements aren't consistent and vary depending on unit. 

 Also, I like hefty headroom and having volume control somewhere around the middle rather than on either extreme. So I'd personally prefer an amp that can drive any load at high levels rather than "just enough" for one headphone I happen to be interested in. Sometimes I just listen louder than average volumes based on mood. I have quite a few recordings at more or less 30 dB DR too that don't hit those peaks consistently enough to damage hearing, when I compensate for the generally lower volume playing.

Fair enough, and that's why I said for me, 105 dB SPL is my target. I rarely listen to classical music.

 

[ruthieandjohn]

@miceblue  Thanks for posting the first (well not counting Tyll's original post) frequency response of the HE1000.
 
You clearly have thought about headroom and average listening levels,  Thanks so much for your thoughts.  Sounds like you suggest a 25 dB headroom above whatever listening level you really use, which in your case is around 87 dB... right?  That starts to poke at this mysterious argument that says that even though a tiny FiiO amp can get the say 112 dB out of the HE1000, it is still the wrong amp because some other amp can get 25 dB more.
 
Again, thanks!