= Hifiman HE500 & HE400 Jergpad Mod v2.5 =
Feb 7, 2014 at 2:46 PM Post #1,561 of 1,710
Yes. If you look at the measurements on the first page, you'll see that the vent adds a significant bass boost at 50Hz but the bass rolls of quickly afterward (AKA no more sub bass extension). Some will say that the vent provides for a much airier sound though.


I'm a little new to the audiophile scene... could you describe what I might hear differently with the back vent mod and without? I'm not sure what "sub-bass extension" is...
 
Feb 7, 2014 at 3:07 PM Post #1,563 of 1,710
I'm a little new to the audiophile scene... could you describe what I might hear differently with the back vent mod and without? I'm not sure what "sub-bass extension" is...

 
Sure, no problem. The HE-400's have a very linear frequency response (aside from the upper midrange) with stock pads. What this means is that the response (volume) is consistent with each frequency/pitch. When reading the graph, look at the green line. The volume is on the y-axis and the frequency is on the x-axis. "Sub bass extension" is a driver's ability to have a fairly flat response all the way into the sub bass region (really really low bass notes). If you look at the HE-400 graph with vents, you'll see that there is a bump at 50Hz and a steeper "roll-off" at lower frequencies. This means that 50Hz will be louder, more prominent, while the frequencies below 50 measure "quieter".
 
The perceived sound is a little subjective. The lack of sub bass extension in 'vent-mode' may not be easily audible. First, hardly any music (aside from electronic) has anything under 50Hz. Second, the vent also affects the audible distortion (the lines on the graph below the green line) which can induce a perceived amount of sub bass that isn't actually there.
 
From my own personal experience, the vent causes two major changes: more rumbly bass (50Hz) and more hollow. The vent provides for a more v-shaped response (bass and treble are prominent on the frequency response, as if it were a "V") which makes the midrange sound hollow and recessed. In the end, I opted to not use the vent mod.
 
Feb 7, 2014 at 3:10 PM Post #1,565 of 1,710
Based on reading these, I'd probably do the vent part on the HE-400 if I had it. That extra sub bass really isnt much to other than electronic / dubstep / trap type of music...
 
Feb 7, 2014 at 3:12 PM Post #1,566 of 1,710
   
Sure, no problem. The HE-400's have a very linear frequency response (aside from the upper midrange) with stock pads. What this means is that the response (volume) is consistent with each frequency/pitch. When reading the graph, look at the green line. The volume is on the y-axis and the frequency is on the x-axis. "Sub bass extension" is a driver's ability to have a fairly flat response all the way into the sub bass region (really really low bass notes). If you look at the HE-400 graph with vents, you'll see that there is a bump at 50Hz and a steeper "roll-off" at lower frequencies. This means that 50Hz will be louder, more prominent, while the frequencies below 50 measure "quieter".
 
The perceived sound is a little subjective. The lack of sub bass extension in 'vent-mode' may not be easily audible. First, hardly any music (aside from electronic) has anything under 50Hz. Second, the vent also affects the audible distortion (the lines on the graph below the green line) which can induce a perceived amount of sub bass that isn't actually there.
 
From my own personal experience, the vent causes two major changes: more rumbly bass (50Hz) and more hollow. The vent provides for a more v-shaped response (bass and treble are prominent on the frequency response, as if it were a "V") which makes the midrange sound hollow and recessed. In the end, I opted to not use the vent mod.


Thanks for the great explanation. I'm actually thinking now that I don't want to the vent mod - I'm trying to get rid of sibilance and don't want to boost the treble with the more V-shaped response. I also don't want to detract from the mid-range.
 
Feb 7, 2014 at 3:19 PM Post #1,568 of 1,710
 
  Also, I am wondering if this mod makes the HE-400 superior to the Fidelio X1

 


I'm pretty sure the stock HE-400 is already superior to the X1. If I have time I can do a side by side comparison of the two since I just received the X1 and modded my HE-400 pads.


I would be very interested in a comparison. I think a lot of other people would be as well. From what I've read the Fidelio has been pitched as great jack-of-all-trades type headphones, so I'm interested in seeing how it compares to a modded HE-400.
 
Feb 7, 2014 at 3:19 PM Post #1,569 of 1,710
  From my own personal experience, the vent causes two major changes: more rumbly bass (50Hz) and more hollow. The vent provides for a more v-shaped response (bass and treble are prominent on the frequency response, as if it were a "V") which makes the midrange sound hollow and recessed. In the end, I opted to not use the vent mod.

 
I know you're responding to a question about the back vent mod on the HE-400s, but can you speak to the effects on the HE-500s?  Appreciate it.
 
Feb 7, 2014 at 4:11 PM Post #1,570 of 1,710
 
Thanks for the great explanation. I'm actually thinking now that I don't want to the vent mod - I'm trying to get rid of sibilance and don't want to boost the treble with the more V-shaped response. I also don't want to detract from the mid-range.

 
The vent mod does not increase treble, the bass just becomes more pronounced (treble is already pronounced). The hole dampening from the jerg pad is essential to smooth out the treble.
   
I know you're responding to a question about the back vent mod on the HE-400s, but can you speak to the effects on the HE-500s?  Appreciate it.

 
I did a fair amount of listening with the stock velours but most of my listening with the full blown, vent modded jergs. The issues with big bass and hollowness are not shared on the HE-500. I wish I would have done some listening without the vents on the HE-500 but the complete jerg pad was clearly a step up from the velours.
 
 
 
One thing I've mentioned in the past is that the size of the vent will certainly change the sound on the HE-400. My first pair of jerg pads (self made) had a very small vent compared to the pads made by modulor. The bass quantity was noticeably less on my pair, but still pronounced over stock. This also made my pads less hollow sounding. If you want to experiment, make your own vents and change the sizes. Without a vent, you can count on linearity and sub bass extension. With a large vent, you can say hello to bass and goodbye to pianos. I'm sure there is a great 'sweet spot' for everyone.
 
Feb 10, 2014 at 7:51 PM Post #1,571 of 1,710
Really enjoying this mod, thanks for your work Jerg. and thanks to Modulor for constructing them for me.
 
Feb 10, 2014 at 7:53 PM Post #1,572 of 1,710
   
The vent mod does not increase treble, the bass just becomes more pronounced (treble is already pronounced). The hole dampening from the jerg pad is essential to smooth out the treble.
 
I did a fair amount of listening with the stock velours but most of my listening with the full blown, vent modded jergs. The issues with big bass and hollowness are not shared on the HE-500. I wish I would have done some listening without the vents on the HE-500 but the complete jerg pad was clearly a step up from the velours.
 
 
 
One thing I've mentioned in the past is that the size of the vent will certainly change the sound on the HE-400. My first pair of jerg pads (self made) had a very small vent compared to the pads made by modulor. The bass quantity was noticeably less on my pair, but still pronounced over stock. This also made my pads less hollow sounding. If you want to experiment, make your own vents and change the sizes. Without a vent, you can count on linearity and sub bass extension. With a large vent, you can say hello to bass and goodbye to pianos. I'm sure there is a great 'sweet spot' for everyone.


I did notice something about that.
 
when I used velours, immediately the bass felt like it made less of an impact, but honestly I think it might have to do with the fact that the pleathers squish and your ears might be closer to the driver (or something like that).
 
Regardless, I did notice an increase in bass with the backvent mod and it's back nearly to the quantity i had with stock pleathers.
 
Feb 11, 2014 at 3:41 PM Post #1,573 of 1,710
   
The vent mod does not increase treble, the bass just becomes more pronounced (treble is already pronounced). The hole dampening from the jerg pad is essential to smooth out the treble.
 
I did a fair amount of listening with the stock velours but most of my listening with the full blown, vent modded jergs. The issues with big bass and hollowness are not shared on the HE-500. I wish I would have done some listening without the vents on the HE-500 but the complete jerg pad was clearly a step up from the velours.
 
 
 
One thing I've mentioned in the past is that the size of the vent will certainly change the sound on the HE-400. My first pair of jerg pads (self made) had a very small vent compared to the pads made by modulor. The bass quantity was noticeably less on my pair, but still pronounced over stock. This also made my pads less hollow sounding. If you want to experiment, make your own vents and change the sizes. Without a vent, you can count on linearity and sub bass extension. With a large vent, you can say hello to bass and goodbye to pianos. I'm sure there is a great 'sweet spot' for everyone.

 
So I listen to a lot of classical and I was wondering if the back vent mod would be recommended for classical listening or would I be better off without it.
 
Feb 11, 2014 at 3:43 PM Post #1,574 of 1,710
   
So I listen to a lot of classical and I was wondering if the back vent mod would be recommended for classical listening or would I be better off without it.


Yes. Classical needs better center imaging and imaging in general--the back vent mod helps with that. Sub bass is less needed with classical, so yes IMO do it
 
Feb 11, 2014 at 3:49 PM Post #1,575 of 1,710
   
So I listen to a lot of classical and I was wondering if the back vent mod would be recommended for classical listening or would I be better off without it.

With the HE-400? Absolutely not. I can see no advantage of having the vent on the HE-400 unless you want thumping bass (EDM or rap). I do however recommend it on the HE-500.
 
EDIT: I think I need to further clarify the fact that the vent mod does not have the same effect on the HE-400 and the HE-500.
 

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