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HD6XX bass

KaiserSoze

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Not proof, just the most likely explanation given the data, see below.

HD600:
View attachment 75910

HD650:
View attachment 75911

HD58X:
View attachment 75912

HD598:
View attachment 75913

etc. etc.

The major commonality between all these is the raised upper-bass / lower midrange (seen clearly in the upper red curves), and far more Sennheiser headphones have this feature than don't. The psychoacoustics of lower frequencies better masking higher ones is consistent with this feature causing a slightly veiled sound. What the veil is not likely due to is a lack of treble, as several of Sennheiser's headphones do not lack treble, yet some say still sound slightly 'veiled', such as the HD600 above.

Okay, whatever. I was only saying that several years back the most common criticism of the Sennheiser headphones was the Sennheiser "veil" and now it is the lack of bass. I don't have any disagreement with the frequency response curves. However the totality of your reasoned argument hinges crucially on the idea that a certain kind of frequency response will produce the effect that goes by the name "veiled sound". Were I to want to say something like what you are saying, I would have to say something along the lines of "Many Sennheiser headphones share a characteristic in their frequency response, which has a particular sonic signature and which is presumptively the sonic signature that many people report hearing and refer to as the 'Sennheiser veil'. Although, there is no way to know with complete certainty whether everyone listening to Sennheiser headphones has heard the exact same thing and is referring to exactly the same thing when they speak of the 'Sennheiser veil'."
 

Kouioui

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85dB is perfectly safe for several hours daily. Unless you listen at at that level all day long there's not really much to worry about.
That why I said significant periods of time. No audio engineers I know will track or mix 40hrs a week at 85dB. There are some people who wear earbuds every day, all day listening at high levels. I can tell by conversing with them with the buds out their hearing threshold has dropped from the volume of their voice and having to speak up for them to understand me.
 
OP
T

TankTop

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Here's exactly how the 330 ohm output impedance of the NAD 705 will change the frequency response of your HD6XX (calculated using Reference Audio Analyzer's extremely useful tool here):

View attachment 75882
So, around a 1.5dB increase in mid/upper bass over your iPhone XS (which I'm presuming you're using with the Apple dongle which has negligible output impedance), if you volume match at around 1kHz. (Or conversely a 1.5dB decrease in mids/treble, depending on how your brain will perceive the change.) This may actually be less of a difference than using your Marantz SR5014, as AVRs are notorious for having ridiculously high output impedances on their headphone outs (my Denon's is a whopping 500 ohms!). One other thing such a high output impedance will do is reduce the electrical damping, which anecdotally may result in the bass sounding less controlled (although I'm not aware of any hard evidence this is effect is audible).

Wow, the NAD (iPhone dongle to RCA) is significantly better than the iPhone or Marantz. I actually completely defeated the bass and left treble flat (noticed after that loudness was on) and the headphones sounded much better, very warm and only lost a little control of bass with depth charges on Greyhound.
If I decide to refresh the NAD could the 330OHM resister be replaced with something more appropriate or is it more complicated than than?
 

maverickronin

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That why I said significant periods of time. No audio engineers I know will track or mix 40hrs a week at 85dB. There are some people who wear earbuds every day, all day listening at high levels. I can tell by conversing with them with the buds out their hearing threshold has dropped from the volume of their voice and having to speak up for them to understand me.

So, in other words, 85dB is a perfectly reasonable volume for a few hours per day of recreational listening. Consequently, distortion performance at that level is also a reasonable concern.
 

Kouioui

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@maverickronin that's correct but I don't believe distortion with EQ at 85dB is much of an issue with the 650/6XX, properly driven by the amps most audiophiles pair with them. Higher volumes I agree there's an issue. I'm going by someone with pro experience measuring transducers :

Don't forget how insensitive we are to THD at low frequencies.For a 40 Hz tone you can very often go to 3-5 % THD before you notice any change, let alone the sound getting worse.
 

maverickronin

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@maverickronin that's correct but I don't believe distortion with EQ at 85dB is much of an issue with the 650/6XX, properly driven by the amps most audiophiles pair with them. Higher volumes I agree there's an issue.

I don't really disagree with that, but...

The post I originally replied to implied that distortion at 85dB was irrelevant because it wasn't safe to listen that loud in the first place, not because it was still inaudible.
 

Kouioui

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Consequently, distortion performance at that level is also a reasonable concern.
How else was I supposed to interpret this? The graph I shared shows the THD lower than the 3-5% threshold. This thread implied the bass performance was distorted on all 6 series Senns but the data shows otherwise unless you exceed safe listening levels.
 

solderdude

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(EDIT: I did the above scratch calculation before I saw the post from bobbooo, showing the change predicted by RAA. In trying to reconcile the difference, I will note that the 330 Ohm resistor is not the full output impedance of the amplifier, and all I considered was the 330 Ohm resistor. Also, my calculation of 1.17 as the voltage gain at 90 Hz, which corresponds to +.7 dB, is for voltage. To calculate the corresponding gain in acoustic power, the square of 1.17 is about 1.4, or 1.4 to 1.5 dB. However the RAA graph indicates about +3 dB, so there is a discrepancy, possibly explained by my not having considered the full output impedance of the amplifier.)


The 330 Ohm is the exact output resistance of the amplifier (+/- a few percent tolerance of the resistor + a few mOhm of the speaker amp output)
When I do my calculations based on impedance plots provided by Tyll, as well as my own measurements with 120 Ohm out the (mid)bass boost is 2.2dB. Upper treble will increase by approx. 1dB as well.
 

cistercian

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I have the HD600 and just accept that the bass rolls off. I really love them but since they are
open I can't use them for monitoring while transmitting (feedback!). I ordered a set of the HD280 pro
and the HD300 Pro. I did not intend these for music, just comms work. The 300 has been panned galore
for being a bass head set of cans. They go low very well. I have found the midrange much better than I had hoped
for and the highs are nice too. I used them to listen to some music from the RME and I was delighted with them!
They have a short cord and at 200 bucks are pricey...but I like them much more than the 79 dollar HD280 Pro.

I heard so much bad stuff about them...but also a couple of good reviews of them. If you don't mind closed phones
they sound pretty nice to me if you want to go low. They sound a bit Harmon curve like to me. I like them!
I used closed phones for decades before I got my HD600...so I am used to them.

The HD300 Pro goes very low with excellent control. They really sound nice to me. YMMV and I am 58.
They are going to be superior for radio work...and for music where I want the bass to deliver!

The RME makes the HD600 sound better...but bass roll off is there in spades. Sub bass is not the 6xx series claim to
fame. The epic detail and relatively flat response curve is the real strong point of the series and the 600 remains my favorite.

Good luck OP whatever you decide to do!
 

Bob-23

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If I decide to refresh the NAD could the 330OHM resister be replaced with something more appropriate or is it more complicated than than?
You could reduce output impedance to 30 Ohms by putting a 33 Ohms (metal-film, 5W) resistor between each channel and ground - output voltage will drop drastically as an effect, but it still can be sufficient. (Can be done e.g. in a box between headphone out and headphones.)
 

solderdude

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If I decide to refresh the NAD could the 330OHM resister be replaced with something more appropriate or is it more complicated than than?

When you plan to open it up you could get some inspiration from here and lower the output resistance even further. I figure you can mount the 2 extra needed resistors on that same resistor PCB as well.

R1 (on the linked page) is currently the 330 Ohm/2W = R157 and R158
R2 can be mounted instead instead of the 2 capacitors C133 and C134.
 

bobbooo

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Wow, the NAD (iPhone dongle to RCA) is significantly better than the iPhone or Marantz. I actually completely defeated the bass and left treble flat (noticed after that loudness was on) and the headphones sounded much better, very warm and only lost a little control of bass with depth charges on Greyhound.
If I decide to refresh the NAD could the 330OHM resister be replaced with something more appropriate or is it more complicated than than?

If you don't want to go to the terrible of opening up the NAD, you could just get something like the iFi Ear Buddy, which Amir reviewed here. This should reduce the output impedance of any source to around 3 ohms (so you could also use it with your Marantz AVR).
 
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solderdude

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Alas this is not an option.

The ear buddy is 18 Ohm load.
Combined with the 330 Ohm series resistor + its attenuation this will give way too much attenuation (-40dB).
At full power there would be 0.27V avalaible on the output of the ear buddy.
This is 3x less than a regular phone puts out.

The only viable way is using the link in post #112 if you want an output resistance lower than 30 Ohm (post #111)
 

bobbooo

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Alas this is not an option.

The ear buddy is 18 Ohm load.
Combined with the 330 Ohm series resistor + its attenuation this will give way too much attenuation (-40dB).
At full power there would be 0.27V avalaible on the output of the ear buddy.
This is 3x less than a regular phone puts out.

The only viable way is using the link in post #112 if you want an output resistance lower than 30 Ohm (post #111)

Ah ok, it worked fine on my AVR.
 

solderdude

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But that one probably has a much lower output resistance ( <<330 Ohm)
 

bobbooo

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But that one probably has a much lower output resistance ( <<330 Ohm)

Nope, it's much higher, at 500 ohms. Innerfidelity rated the HD650 (i.e. same as OP's HD6XX) as needing just 0.2Vrms to reach 90dB by the way.
 

solderdude

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Ear buddy output is 3.3 Ohm, series resistance = 515 Ohm.
Attenuation is -44 dB (0.006x Uin).
So... assuming your AVR can reach 35V full power = 0.22V output voltage with the amp on max.
That is 5x lower than a phone !!!
The HD6XX = 91dB peak so about 78dB average SPL can be reached with the AVR at clipping level (max volume).
When you would apply Harman EQ the average SPL would be 68dB average.

There are lots of people claiming the HD650 is loud enough on a phone though, this is only about half as loud (-14dB opposite a phone output)
 
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bobbooo

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Ear buddy output is 3.3 Ohm, series resistance = 515 Ohm.
Attenuation is -44 dB (0.006x Uin).
So... assuming your AVR can reach 35V full power = 0.22V output voltage with the amp on max.
That is 5x lower than a phone !!!
The HD6XX = 91dB peak so about 78dB average SPL can be reached with the AVR at clipping level (max volume).
When you would apply Harman EQ the average SPL would be 68dB average.

There are lots of people claiming the HD650 is loud enough on a phone though, this is only about half as loud (-14dB opposite a phone output)

I was testing it with my HifiMAN HE4XX. They must be a lot less demanding than the HD650/6XX (can't find measured specs for the HE4XX). I also don't listen at deafeningly loud volumes.
 

solderdude

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HE4XX is 2 dB/V more efficient so 80dB average is the max. loudness (93dB peak SPL)

The fun part is you could easily use the HE4XX directly from the AVR it could play 20dB louder. The HE4XX doesn't care about higher output resistances. It would be kind of 'current' driven.
Of course when the AVR is very noisy it could be a reason to use an attenuator.

Deafeningly loud would be around 100dB average.
 

bobbooo

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HE4XX is 2 dB/V more efficient so 80dB average is the max. loudness (93dB peak SPL)

The fun part is you could easily use the HE4XX directly from the AVR it could play 20dB louder. The HE4XX doesn't care about higher output resistances. It would be kind of 'current' driven.
Of course when the AVR is very noisy it could be a reason to use an attenuator.

Deafeningly loud would be around 100dB average.

Well either I have very sensitive hearing or that difference in sensitivity between the HE4XX and HD650 isn't correct, because at max volume with the Ear Buddy it's painfully loud. Where did you find measured specs for the HE4XX?

Oh and I only tested them with the Ear Buddy out of curiosity, as obviously they have flat impedance so output impedance doesn't really matter. I usually use them straight into the AVR. The Ear Buddy is for my closed-back Focal Spirit Classics (to reduce noise) and my IEMs (the latter having wild impedance swings so it's definitely required).
 
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