The HE-400i has a peak at around 8khz, and when I was listening to a track with a cowbell or triangle it was very "hot" and would be fatiguing. Other tracks with different programme would be fine. And some people may not even be bothered.
I agree about planars, when I heard the HE-400i, my first experience of a planar, I thought "this is what I've been looking for".
The bass response can be incredible too, I think this may be part of the reason they sound like they do. The bass of a planar compared to a dynamic is like listening to a bookshelf speaker in a poor room, compared to a full range sealed bass speaker in treated room.
I agree about planars, when I heard the HE-400i, my first experience of a planar, I thought "this is what I've been looking for".
The bass response can be incredible too, I think this may be part of the reason they sound like they do. The bass of a planar compared to a dynamic is like listening to a bookshelf speaker in a poor room, compared to a full range sealed bass speaker in treated room.
badboygolf16v, it is slightly off topic but I have to say that bass of 50mm dynamic is crazy low freq. and punchy, I don't think if bookshelf comparison is correct.
I've found freq.responses for he400i and he560(innerfidelity), and I see just +3db bump on 400i vs 560. See attached 400i vs 560 difference plot. Actually, it is pretty easy to adjust 7pcs parametric EQs of TAS5558 IC to fit one headphone freq.responce to another one. I trying to write Matlab code for automatical biquads setup for such compensation 😉 Apparently, 400i to 560 compensation would not be too interesting because the difference is not as big as vs HD800S or LCD2.
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and the result is here 😉 Actually, it is pretty much manual adjustment with Matlab visualization. Blue - difference he400i vs hd800s, red - residual difference he400i vs hd800s after 7 pEQ compensation, green - smoothed residual difference he400i vs hd800s after 7 pEQ compensation.
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For sure I was over generalising with my comments on dynamics. It's the low distortion of planars in the bass that's perhaps even more impressive than the extension.
The PEQ of the TAS5558 is very useful to have available - this is a Swiss Army knife HPA 🙂 - perhaps Matlab is for the "power user" though...
The PEQ of the TAS5558 is very useful to have available - this is a Swiss Army knife HPA 🙂 - perhaps Matlab is for the "power user" though...
I think I can prepare specially for you a few options of such emulations i.e. he560-> few other headphones responses if you wish 😉 We can use 2 0603 size jumpers to set up the emulation in 4 variants, one of them is linear, another 3 are emulations.
Thanks for the offer. 🙂 The thought of response correction to flat is interesting.
There is a lot of potential here to offer EQs for headphones - Sonarworks have a software product that does just that: flat response for popular headphones.
Here's a hardware project equivalent: Kameleon | DIY-Audio-Heaven
The other possibility is to offer tone control kind of curves i.e. loudness, slope down, presence etc.
Lots of options.
There is a lot of potential here to offer EQs for headphones - Sonarworks have a software product that does just that: flat response for popular headphones.
Here's a hardware project equivalent: Kameleon | DIY-Audio-Heaven
The other possibility is to offer tone control kind of curves i.e. loudness, slope down, presence etc.
Lots of options.
badboygolf16v, I understand that but the PowerDAC already has DSP onboard, so it's an idea to use it more than just DAC. TAS5558 about $5 and if we not using its DSP, I guess we lose $3 ))
Sorry, maybe I didn't make myself clear. I completely agree! 🙂
I was just giving examples to show that it's a good thing to look at.
I was just giving examples to show that it's a good thing to look at.
That would be an excellent result. There are many HPAs being sold with higher output impedance than 1.6ohms.
The low output impedance of 1.6ohms means that True Digital One should be fine to try with my reference IEMs - Etymotic ER4SR. They have separate removable MMCX connectors so I will be able to get some cables that terminate in 3.5mm jacks.
The low output impedance of 1.6ohms means that True Digital One should be fine to try with my reference IEMs - Etymotic ER4SR. They have separate removable MMCX connectors so I will be able to get some cables that terminate in 3.5mm jacks.
I just got the interface PCB and soldered right away 😉
An externally hosted image should be here but it was not working when we last tested it.
The first sample is assembled and tested! No even single mistake, just soldered and turned on 😉 Due to solid polymer caps 1000uFx5pcs dramatically reduced the THD+N at 0dbfs level, for now, it is as low as .012%@1kHz. THD+N = .00* at -1.5db and lower, up to -20db where is noise dominate. Left channel S/N the same -94db, right one improved for 3db(-97db), no idea why, will not surprise if battery powered laptop's USB will probably improve S/N again.
THD vs Frequency(@1VRMS) isn't flat but "mirrored" unlike usual power amps with tons of feedback:
A full-scale output 0dbfs (all figures are at the real he400i headphone load):
An externally hosted image should be here but it was not working when we last tested it.
Frequency response 20-25000Hz +/-.2db but due to open-loop topology it's may have higher tolerance around 20kHz, depends on load impedance:
An externally hosted image should be here but it was not working when we last tested it.
badboygolf16v, I checked out the Kamelion link HE 400i | DIY-Audio-Heaven and found that his measurement very far from mine. He said "measurements are made with a good seal on a flatbed measurement rig", and I did the same measurement, however, my plot has no any 8kHz peak. Please see attached. the green plot is he400i(yellow is my old Sennh, I even don't remember the model #). BTW, that measurement method is too rough to consider it seriously, innerfidelity's plots mad with artificial ear-head and results more practical to me. Yesterday I tried to equalize the green plot into yellow one with 7 parametric EQs and Matlab, the result was sounding really awful on my 400i, and not similar to my old Sennh at all.
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Thanks for the amp measurements, looking good.
From what I've read, headphone measurement can be an interesting task due to physiological differences. Tyll who used to run Innerfidelity wrote about it on occasion, it's an art and a science, that requires a good understanding of the measurement setup in order to properly interpret the results. I have zero experience in the area, I'm just an interested hobbyist.
I wonder if Hifiman's famous "QC" has removed the peak on your set of HE400i? 🙂
For me the HE-560 I will be using have a frequency response that is OK for me, so I will probably be OK without EQ.
From what I've read, headphone measurement can be an interesting task due to physiological differences. Tyll who used to run Innerfidelity wrote about it on occasion, it's an art and a science, that requires a good understanding of the measurement setup in order to properly interpret the results. I have zero experience in the area, I'm just an interested hobbyist.
I wonder if Hifiman's famous "QC" has removed the peak on your set of HE400i? 🙂
For me the HE-560 I will be using have a frequency response that is OK for me, so I will probably be OK without EQ.
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