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I inverted my graphic eq based on Headroom frequency response graphs. . . does that work or am I... - Page 2

post #16 of 39
Thread Starter 
Quote:
Originally Posted by TMRaven View Post



It's neither, actually.  If I remember correctly, the iPod's output impedance is actually lower than most of the common SS amps people like to run (ie E7/E9) and all 3 of the iPod, iMac and Little Dot have more than enough power to feed the Denons.  When you say they need more power to sound their best, that implies I need to turn them up louder to sound their best, which just isn't true at all.

On to a different note.  EQing by ear isn't good either.  Our hearing has its own loudness curve, and EQing to the point that everything sounds the same in volume just means you'll have hugely exaggerated low end and really high end.  In theory, compensating for computer measurements is the better approach.  

The output impedance of the iPod is still too high (denons tolerate at most 3ohms, 3rd Gen iPod touch is 7ohms) and is not nearly powerful enough. Sounding loud and sounding good are two different things. The denons can be "loud " no problem, but its likely you'll run into the v -shaped response curve everyone talks about, or bloated bass. More power equates to better control over the driver, not necessarily more volume.
Edited by scannon18 - 2/21/12 at 4:50pm
post #17 of 39
Quote:
Originally Posted by scannon18 View Post

The output impedance of the iPod is still too high (denons tolerate at most 3ohms, 3rd Gen iPod touch is 7ohms) and is not nearly powerful enough. Sounding loud and sounding good are two different things. The denons can be "loud " no problem, but its likely you'll run into the v -shaped response curve everyone talks about, or bloated bass. More power equates to better control over the driver, not necessarily more volume.


Denons have a fairly flat impedance curve, the only effect output impedance will have is on electrical damping and I don't know if the effect of such a small output impedance would be noticeable that way. I doubt to the amount implied.

 

More power equates to more volume. It's math. Volume is in dB, power is in Watts, sensitivity is given in dB/mW (or in some cases dB/V, but P = V^2 / R so it all adds up anyway). If it's not used for peaks, that excess power is not being used. There's nothing about "control" here. That would fall under output impedance and damping. If your headphones aren't controlled at volumes the amp can handle, I would look to something faulty or poorly designed/matched, not "underpowered".

 

Myths like these have no place in Sound Science unless you have proof they're true.


Edited by Head Injury - 2/21/12 at 4:57pm
post #18 of 39
Thread Starter 
Well I don't have any graphs, but can you explain why my iPod can run the denons to ear splitting levels but they sound "better " (I.e. more clarity and balance) from my e9 at lower volumes? And this is full knowing the o.I. of the e9 is too high for the denons

Or is this just a "myth" to you, a cognitive bias perhaps? Hard for me to say that empirical evidence is a myth though I don't have any graphs to back it up. You think I work for a head amp company? What motivation do I have for spreading "myths" in your precious little subforum?
post #19 of 39
Quote:
Originally Posted by scannon18 View Post

Well I don't have any graphs, but can you explain why my iPod can run the denons to ear splitting levels but they sound "better " (I.e. more clarity and balance) from my e9 at lower volumes? And this is full knowing the o.I. of the e9 is too high for the denons
Or is this just a "myth" to you, a cognitive bias perhaps? Hard for me to say that empirical evidence is a myth though I don't have any graphs to back it up. You think I work for a head amp company? What motivation do I have for spreading "myths" in your precious little subforum?


Have you compared them blind?

 

People don't spread myths out of malice or motivation. They spread myths because they believe in them.

 

The E9 has exceptionally low IMD, maybe your iPod doesn't.


Edited by Head Injury - 2/21/12 at 5:34pm
post #20 of 39

Why even talk about the output impedance of the iPod being too high when it's a lower output impedance than the E9?  It makes no sense.

 

You might like the E7/E9 because it's being driven off a different dac, different coloration or other things that it might provide compared to the iPod.  I don't like it when people say something doesn't have enough power isn't driving a headphone properly.  Technically speaking my Little Dot shouldn't be able to run the Denons better than the iPod, but I think it sounds better off the Little Dot as well (HRT Music Streamer II DAC)  The iPod has more than enough power to drive the Denons properly.  

 

This is all besides the point, though.  My initial statement was that the Denons had bass that decayed a bit slowly.  Even better damping factor won't magically cure that.  They are a closed headphone, their bass tends to linger.  They also have a noticeable ringing in the 8khz range that leads to excess sibilance and harshness.

post #21 of 39
Thread Starter 

SO let me ask this:

 

Assuming two seperate amps, both solid state and of the same output impedance and both being fed from the same dac, but otherwise different in terms of construction, parts, etc:  Assuming they both get the Denons "loud enough" they will both provide the same performance in terms of clairy, balance, extension, etc?  There will be no audible difference attributable to the amps?  What about their differences in voltage and current output?  Does that not matter at all?

 

 

Is the power aspect of headphones really that simple?  Because if it is I'm beginning to understand some of the local gripes about amp discussion in other forums of Head-Fi

 

 

 


Edited by scannon18 - 2/21/12 at 8:19pm
post #22 of 39
Quote:
Originally Posted by scannon18 View Post

SO let me ask this:

 

Assuming two seperate amps, both solid state and of the same output impedance and both being fed from the same dac, but otherwise different in terms of construction, parts, etc:  Assuming they both get the Denons "loud enough" they will both provide the same performance in terms of clairy, balance, extension, etc?  There will be no audible difference attributable to the amps?  What about their differences in voltage and current output?  Does that not matter at all?

 

Is the power aspect of headphones really that simple?  Because if it is I'm beginning to understand some of the local gripes about amp discussion in other forums of Head-Fi


Current and voltage is power. P = I * V. Also, P = V^2 / R, so how much voltage and current is needed for a given amount of power depends on the headphone's impedance. The Denons have low impedance, so they need current. Current is what solid state amps typically specialize in.

 

Extension and balance is frequency response, and a good solid state amp will roll off by about an imperceptible 0.25 dB or so by 20 Hz and 20 kHz. Nothing to do with power.

 

Clarity is probably related to THD and IMD. Most good amps will be inaudible here as well, but not always. This sometimes has something to do with power, because some amps will start to increase in THD past a certain "sweet spot" on the volume knob, say around half. Before that sweet spot, noise dominates. Good amps, however, won't reach an audible level of THD until they approach clipping, and noise is low enough that volume shouldn't matter. So ultimately it comes down to the individual amp if power matters here, but if it does it's not going to be helped by huge amounts of head room.

 

When volume-matched, there is no reason I can see that two amps with inaudible distortion, other stuff like channel balance and phase, low output impedance, flat frequency responses, and enough power to reach all peaks should sound different.

post #23 of 39

I have been observing this thread for a while and I feel that from the beginning, your eq process(of eqing based on response graphs) is somewhat wrong. You should measure the response with a measuring mic yourself first. Anyways the argument about the E9 and Ipod is rather lame. For one thing, both are of different impedance and WILL react differently to troublesome loads. The FR and THD distribution you get from the E9 WILL not be the same as the one you find from your Ipod. If you had a mic of sorts, it can be easily proven.

post #24 of 39
Thread Starter 
Quote:
Originally Posted by firev1 View Post

I have been observing this thread for a while and I feel that from the beginning, your eq process(of eqing based on response graphs) is somewhat wrong. You should measure the response with a measuring mic yourself first. Anyways the argument about the E9 and Ipod is rather lame. For one thing, both are of different impedance and WILL react differently to troublesome loads. The FR and THD distribution you get from the E9 WILL not be the same as the one you find from your Ipod. If you had a mic of sorts, it can be easily proven.

 

 

The eq process had to be an extact invert of the headroom graph.  That was the point.  I was trying to see if a balanced sound was achievable by inverting a qualified fr graph.  It isn't.  

 

The argument between the E9 and the iPod arose out of a misunderstanding of how power is applied from amps to headphones.  I had imagined the iPod as not being capable of properly driving my denons because they did not have the necessary power.  Apparently this is actually due to other factors besides power. 

 

Anyway this thread has evolved into a more constructive discussion on the nature of ss amps.  In that vein, I have a few more questions:

 Exactly how many factors are involved in the way a headphone amp will sound with a given pair of headphones?  Can all of these be accurately measured?  People talk about amps as though there is some magic to them, are amps really incredibly simple and straightforward?

 

Could a person theoretically buy an O2 amp, which measures near perfect across the board, and expect no increase in sound quality in an ss amp that costs hundreds, or thousands, of dollars more?

 

Because I was going to invest in an amp but now it seems like it would be more worthwhile to upgrade my dac.

 

 


Edited by scannon18 - 2/22/12 at 3:49pm
post #25 of 39
Quote:
Originally Posted by scannon18 View Post

Well I don't have any graphs, but can you explain why my iPod can run the denons to ear splitting levels but they sound "better " (I.e. more clarity and balance) from my e9 at lower volumes? And this is full knowing the o.I. of the e9 is too high for the denons

 

When making this type of comparison, make sure that:

- levels are matched correctly (i.e. measured, and not just "about the same volume" by ear)

- it is done blindly

- the lower powered device (iPod) does not clip

If the difference is still there, there can be many reasons why the iPod is audibly worse. The only way to know is to analyze its output (playing a set of test signals) while driving the headphones at the same level that was found to sound bad.

 

post #26 of 39
Quote:
Originally Posted by scannon18 View Post

 

 

The eq process had to be an extact invert of the headroom graph.  That was the point.  I was trying to see if a balanced sound was achievable by inverting a qualified fr graph.  It isn't.  

 

The argument between the E9 and the iPod arose out of a misunderstanding of how power is applied from amps to headphones.  I had imagined the iPod as not being capable of properly driving my denons because they did not have the necessary power.  Apparently this is actually due to other factors besides power. 

 

Anyway this thread has evolved into a more constructive discussion on the nature of ss amps.  In that vein, I have a few more questions:

 Exactly how many factors are involved in the way a headphone amp will sound with a given pair of headphones?  Can all of these be accurately measured?  People talk about amps as though there is some magic to them, are amps really incredibly simple and straightforward?

 

There are many, search up amp measurements on innerfidelity to get a good idea. Many manufacturers do not list their specs and even some of those that do list, are measured with no real load(essentially making the measurements useless). All this can be accurately measured and predict(not absolute) headphone sound only if said amp is perfectly linear with different loads(affected by output impedance). 

 

Could a person theoretically buy an O2 amp, which measures near perfect across the board, and expect no increase in sound quality in an ss amp that costs hundreds, or thousands, of dollars more?

It is reasonable to expect something like that, but who knows, there are genuinely good amps out there. Hundreds more surely, I have pitted the O2 against other portables with somewhat higher prices and ruling out mobile tube amps, the other SS ones don't really outmatch the O2. 

 

Because I was going to invest in an amp but now it seems like it would be more worthwhile to upgrade my dac.

 

 

 

post #27 of 39
Thread Starter 

SO, about voltage v. current, I know some headphones like high current and some headphones like high voltage.  Does "power output" (such as the 15mw from my sansa clip) account for both of these? 

post #28 of 39
Quote:
Originally Posted by scannon18 View Post

SO, about voltage v. current, I know some headphones like high current and some headphones like high voltage.  Does "power output" (such as the 15mw from my sansa clip) account for both of these? 


The actual power output depends on the impedance of the headphones, and some other factors, that is why it is commonly assumed that high impedance is harder to drive (since voltage is often the limiting factor). For the same power, high impedance needs more voltage (as P = V^2/R), while low impedance needs more current (because P = I^2*R). However, for the same loudness, different amount of power may be required depending on the sensitivity. That is why a HE-6 needs more voltage (and much more current) than a T70, despite the significantly lower impedance.

 

post #29 of 39
Thread Starter 

Ok, so R is resistance and I is impedance?

 

And does providing high voltage mean a higher output impedance?  Because as I understand it tube amps are very high voltage and have high output impedances

post #30 of 39
Quote:
Originally Posted by scannon18 View Post

Ok, so R is resistance and I is impedance?

 

No, I is current, Z is impedance. The difference between impedance and resistance is that the first is basically a complex number, and accounts for the possibility of there being a phase shift between the voltage and current, while resistance is less generalized and purely real (no phase shift). For a simple "ideal" resistor, impedance and resistance are the same. The imaginary component of impedance is called reactance (X), and it is positive for an inductor, and negative for a capacitor.

 

Quote:

Originally Posted by scannon18 View Post
And does providing high voltage mean a higher output impedance?  Because as I understand it tube amps are very high voltage and have high output impedances


No, it is possible to have high voltage with low output impedance. For example, this is true of any decent solid state speaker amplifier.

 


Edited by stv014 - 2/23/12 at 8:37am
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