[Nidhal]

Hello good folk,
I just got my Sennheiser HD 579 today, I own a Creative Soundblaster Z internal soundcard, the output impedance of that bad boy is I think around 20 Ohms, headphones impedance is 50 Ohms, this does not comply with the 1/8th rule, so what can I do? how do I calculate exactly how much dB I have to strip off the bass?
PS: My motherboard's sound is dead, can't use that to compare.

 

[ProtegeManiac]

I just got my Sennheiser HD 579 today, I own a Creative Soundblaster Z internal soundcard, the output impedance of that bad boy is I think around 20 Ohms, headphones impedance is 50 Ohms, this does not comply with the 1/8th rule, so what can I do? how do I calculate exactly how much dB I have to strip off the bass?

Unless you can measure that or you have all complete specs on the amp circuit and the headphones, no way to know. Best you can do is just experiment. Cut bass until it's even or tight with other frequencies.

Note though that "tight" isn't exactly easy to get given that lower damping factor tends to mean it's naturally not as tight, even if the effect is the opposite, ie, in some cases high output impedance can result in making the bass weaker (but still kind of loose and lacks definition).

 

[Nidhal]

Unless you can measure that or you have all complete specs on the amp circuit and the headphones, no way to know. Best you can do is just experiment. Cut bass until it's even or tight with other frequencies.

Note though that "tight" isn't exactly easy to get given that lower damping factor tends to mean it's naturally not as tight, even if the effect is the opposite, ie, in some cases high output impedance can result in making the bass weaker (but still kind of loose and lacks definition).

Thanks, but I don't know what "tight" means exactly, the bass from what I've tested so far for the last couple hours is there, definitely there, maybe, just maybe a little bit bloated, but I'm not sure how to tweak it to be flat for every song, I might decrease 120Hz band by like 4dB and it will sound great on one song, but not so much on another...
If someone knows some equation for this it will be great, if not, thanks for the help anyways I might have to start EQ'ing.

 

[NA Blur]

Are you saying you hear to much bass?

The 1/8 the rule is more of a design concern especially if you don't hear distortion in the bass.

I wouldn't worry about it.

The average impedence is 77 at the fundamental resonance of the driver where it often matters most. That gives you a slightly higher damping factor.

If you're hearing crazy bass from these you either have too much EQ going on or the music you are listening to has way too much bass in it. The 579 should not sound super bassy.

 

[Me x3]

-1.5dB peak centered at 110Hz (flat below 40Hz and flat over 250Hz)

 

[castleofargh]

I have to agree with @ProtegeManiac. without the ability to measure your gear, just making assumptions doesn't really ensure to improve anything.
of course you can go with the assumption the your output is dead flat at 20ohm at all frequencies(but is it?), and that your output behaves the same no matter the load(also not a given) then look for an impedance curve of the headphone(hope your pair has the same), and predict the variations in FR compared to some other output impedance value.
it's actually not that hard once you're confident in your data. but getting reliable data is the issue.
based on https://reference-audio-analyzer.pro/en/report/hp/sennheiser-hd-579.php you can expect something between 1.5 and almost 2dB boost centered around 100hz area depending on the impedance you aim at as reference value. so you could try attenuating like @Me x3 suggests but keep in mind that it's an approximation for only one aspect of the response. based on my own preferences, I would probably not mind that little boost too much but instead I would try to boost around 40 or 50hz by a few db, and try to get the 150-1000hz region to be closer to flat or maybe even slightly recessed(but really just a little because I like how it sounds most of the time on headphones).

overall I'd advise to go with your guts if you EQ. the headphone under perfect conditions isn't flat, your own head needs whatever it needs that a dummy head won't predict for you, and then you have your own taste. I'm all for an objective approach, but if it's going to be an incomplete approximation, you're probably better off not hanging too much on the idea that it's objectively better that way. try a few stuff and keep what you like, that's usually my choice for EQ.

 

[ProtegeManiac]

Thanks, but I don't know what "tight" means exactly

It means what should sound like a solid and tight "THUD!THUD!THUD!THUD!THUD!THUD!THUD!THUD!THUD!THUD!THUD!THUD!" on the bass drum sounds more like a "thWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUthWUUUUUUddd."

A series of plucks on the double bass that should like tight "dwuu, dwuu, dwuudwuuudwuuududwwuuudwwuudwwuumm" sounds more like "DWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUUDWUUUUMMMM."

Basically it's like when describing a body. Tight is like Scottie Pippen or David Robinson's muscle definition with atheletic capabilities. Loose and flabby bass is like loose and flabby "Im all about tha bass, 'bout tha bass, no treble" or why loud bass music comes with similar lyrics, like "bubble butt, bubble bubble bubble butt" and somebody's rear vibrating like Jell-O.

the bass from what I've tested so far for the last couple hours is there, definitely there, maybe, just maybe a little bit bloated, but I'm not sure how to tweak it to be flat for every song, I might decrease 120Hz band by like 4dB and it will sound great on one song, but not so much on another...
If someone knows some equation for this it will be great, if not, thanks for the help anyways I might have to start EQ'ing.

There's no clear equation on that. Absolute best you can do is set up measurements and try to EQ to flatten everything. Problem with that is:

1. EQ isn't exactly going to get you adjustments that will be a negative image of whatever irregularities are there

2. The cost of using a ballistic dummy head with ear canals, the mic, and all other equipment would only be worth it if you're going to use it the Inner Fidelity does it. Otherwise you might as well just buy a different headphone, if not also an amp.

Second best option: generate some sine waves using the same logarithmic scale used by headphone response graphs (ie 10s until 100hz, 100s until 1000hz), and then compare every frequency sine wave to how loud 1000hz is and EQ from there.

Note again that having them as even as possible is no guarantee since what is even to human hearing might not necessarily be absolutely equal since the brain tends to have a bias for midrange (the eardrums are otherwise fine) the same way the brain ignores the fact that your nose is in your FOV, on top of which, the damping factor is still low, which is why when the opposite effect happens the bass gets weaker but it's still loose.

 

[Nidhal]

Thank you everyone for the tips.
Well, it looks like the songs I was playing were a little on the bassy side, tried with other headphones and even earphones, the bass went absolute berserk on cheaper headphones.
I dropped -1.5dB like @Me x3 suggested (I wasn't using any EQ before), even though it's hardly noticeable, I can still feel good about it knowing it's closer to flat than not.
@ProtegeManiac Haha, nice explanation! yeah gotcha, tight and quick bass is what you want, with some sub bass as well.
This looks like it's more complicated than I thought, I'll just stop nit picking and enjoy my new pair of headphones.

 

[Nidhal]

Um, how do I mark this thread as SOLVED?
I'm new here

 

[ProtegeManiac]

Um, how do I mark this thread as SOLVED?
I'm new here

Edit the first post, then edit the title to indicate "SOLVED."