EDIT from a real computer:
Sorry if anyone tried to wade through this - I had to wait for my train for ~40 minutes and figured I'd wing it on the phone. Probably won't attempt that again.
I apologize to max if my original reply seemed too curt - was just trying to get through it, but scrolling a large reply was kind of challenging (especially with cold fingers).
I think you may have over judged my statement. I never said 1500mw was the nominal rating, i stated that, that power can be produced at it's Nominal OHM level being 70ohms.
No power is being produced or created, and nominal impedance is irrelevant here. 1500mw is the max input they can take. And that's probably a liberal number (as is sony's style) - it should be assumed a functional max. But you'll never see it in normal usage - way too hot given the sensitivity ratings. You also have to remember that Sony is *notorious* for goosing numbers on higher end products, just to set them apart from other products (like the SA5k claim to have a top-end of 110khz - seriously?). It's just a DNE value, it doesn't really speak to performance anywhere, and it certainly isn't a power requirement figure (that'd be the sensitivity value).
As you may very well know these power ratings are not measured through out an entire frequency ranged but at a standard 1khz test level.
No; only znom requires a freq ref as impedance is complex. It doesn't matter how you dump 1500mw into them - they will have a bad day. Again - this is just a max power input spec, it means nothing for sonics.
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I am of the understanding that most companies only list there peak power level oppose the the nominal power level which is almost always 25-75% of its max in some cases even less, but in terms of the SA5ks i doubt your paying a premium to only get less than 25% of its max power level.[/quote]
Truly impossible to infer - they don't provide enough data to make this statement with any confidence. But again this spec has nothing to do with sonics. If companies were more upfront with how they're creating specs, you could go down this path, and it would net you some legitimately useful information about the limits of the driver, but for all we know 1500mW is essentially a PMPO rating, and you can only reproduce it in a lab for a fraction of a second. Again, we're talking about 1.5W into a 50mm driver - that's pretty intense when the driver isn't designed to move very aggressively (generally headphone drivers don't have surrounds or suspensions like conventional cone drivers in loudspeakers - they're usually more rigidly designed because it's assumed that they won't be moving very much, and the stiffer and lighter you can make them, the better (for sonics - this applies to speaker drivers too, it's why materials like Kevlar are so popular (this was actually mentioned in this thread a few pages back, Anaxilus brought it up)).
1500mw is without a question the 100% load rating, and when it comes driving components or anything for that matter, it should never be done at 100% load, that's basic practice. So even if your amplifier is producing 1500mw or more it shouldn't be a problem if your utilizing it at 25-75% load.
Your thinking about power in linear and arbitrary terms. 75% vs 100% is inconsequential (you won't notice it) - its a logscale and generally speaking you will see a fraction of a mw with the SA5k due to their high sensitivity. The steps (if you want to talk perception) will be 10x at a time, so you'd go from 1 mW to 10 mW to 100 mW to 1000 mW and so on. 750 mW to 1000 mW or 75 mW to 100 mW isn't worth writing home about.
For power supply, and talking about the amplifier's output curve/distortion you're more or less on the money (but amplifier topology and power supply design certainly will change what that range can look like) - basically the bottom and top 5% are where you'll usually see the most (non-clipped) distortion. When you go over the top-end "limit" is where you get clipping, where the amplifier is literally "clipping" the waveform (hence the term) and producing nasty square wave. That can damage drivers.
The problem i see is that you can probably produce reasonable sounding power at 30-60ohms but creating its rated power at the 70ohm level is a much more challenging task.
From the amplifier's perspective, 60R to 70R is more or less inconsequential - Ohm's law will dictate that the voltage/current relationship will vary slightly, but it isn't that dramatic. When you double or halve impedance is where you start to see big changes. Most amplifiers have no problems with the 75R Znom on the SA5k, especially given how sensitive they are.
Same thing with that of the K701 and HD 650's is to create suitable power at its given ohm rating. Most problems with speaker set ups is that 50% output load is not equal to 50% power rating of the drivers, and it seems like with these high clarity SA5ks and other Sony's alike making this vary apparent in the form of brightness and impurity notification instead of clipping and distortion.
Again, nothing is "creating power" - I'm not sure where you're going with the speaker setup point, but with the SA5k the brightness is just part of their sonic signature. It's just how they are. Clipping and distortion happen when the amplifier or the headphones (or both) are over driven. Look at Tyll's data for example - when he increased their output level to 100 dB (which is a 10x increase in power over the 90 dB level), distortion goes up pretty heavily (especially in the bass). You could also clip the input block of the amplifier, which will give you clipping through the cans, but it isn't the fault of the cans or the amplifier - it's the source.
But you stated undercutting power may be a wrong way of looking at it, it could simply be they are bright and thats all there is to it. I have my doubts because the ex-1000's i have, seem to be have a similar problem.
Apples and oranges.
I can see how the k701 can be pickier simply because it has a much smaller window of power requirement with a similar ohm rating (62 ohms).
No. That isn't how it works - again its just a max input value. The 701 just can't handle as much input power. It isn't a "power requirement" value. Also, it isn't "ohm rating" (this is one of my longstanding pet peeves - there is no such thing as an "ohm rating"); it's impedance (or complex resistance in an AC system, if you aren't big on the whole brevity thing).
It creates its nominal power level at almost a third of what the SA5ks do.On the contrary it is probably much easier to over power the k701's as well?
Not quite - the 701s need something like 10 to 100 times the input power for the same level output. Yes if the specs are accurate they will blow sooner.
Speaking on in terms of the Senn's, these have a much higher impedance so creating power in its nominal range can be a trick as well for reasons you know of. Same for any other high impedance driver.
Yes and no - they need relatively more voltage (Ohm's Law) but their real "challenge" is how reactive they are, which explains a lot of the "hard to drive" complaints. The SA5k don't have that problem. Basically what it means is as you vary Zsource, you will change the FR on the HD 650; the SA5k are much more stable though, and the FR variations will be very minor.
So with the Fiio E9 is it not the case your undercutting power?
No - the E9 can put around 1100mw into them. It sounds perfectly fine - it just has a higher noise floor and they tend to have noisy pots. Its a fine driver for them when you aren't adjusting the volume and if the slight hiss isn't a bother. Same chip-amp that a lot of higher end amps use (same chip-amp that the VHP-2 uses actually, the VHP-2 just has a better pot and lower noise floor, and is better put together). They sound just like an SA5000 on the E9, and they sound just like an SA5000 direct from speaker taps, or through a few hundred ohms of resistors, or from the VHP-2, and so on. The E9 is just not a good match for very sensitive headphones.
I have the same problem with my Sony EX-1000 which sounds to be similar to the sa5000 in driver design(not in layout as they are completely different design
Apples and oranges.
When i undercut power using a less powerful source(phone,media player, computer output), yes it will play loud, but it has a very piercing and distorted high frequency response,with little to no mids/bass, oppose to when driven on my Nuforce HDP or Schiit Asgaurd they sound almost perfect in the 35-75% load, but still has a hint of distortion around 75-100% power load, this piercing distortion in the higher frequency range seems similar to that of the problem i have when using the less powerful source outputs at 75-100% load, which sounds like and undercutting of power, oppose to peak power distortion/clipping, as i do not hear much clipping around the mids and lows but rather only in the high HZ level which is not indicative to over loading.
What is likely happening here is that your IEMs are reactive (most are), and are changing with variations in Zsource. This is leading to FR variations. The volume references you're providing are basically immaterial because there is no standardization.
The SA5000 are very stable though, and won't change as much. If there were clipping, you'd hear in the bass lines first (as bass demands more power), not in the treble.
In all practices it is said you should make your peak performance at 25-75% load(and an even smaller window if you are looking for extreme efficiency) not at 75-100%, which in some cases when you undercut power you have to use your components at 75-100% to get a suitable listening level. In this zone you are most likely in the clipping and distortion level, but with some drivers and speaker designs clipping and distortion may not be so noticeable, or annoying enough to care. Unlike with these extremely detailed Sony's it is stated by many that you can hear the slightest impurities be it undercutting or over powering or crappy source input. This holds true for the Ex-1000 's as well, meaning Sony has designed something much more intelligent than users make out to be, and most likely the high frequency sensitivity issue could be a cause of under powering? yes i can understand the principle of it being "bright no matter what" but in some cases most people can take that as being piercing if you have sensitive ears, and a lot of people do(which isn't a bad thing).
Clipping always sounds like trash and can destroy drivers depending on how bad it is (clipping is bad news) - but I doubt anyone will run an amp into clipping with the SA5k. You might overload the amp's input block but that is different. The SA5k have been consistently measured as bright by various independent sources - they're just voiced that way and aren't for everyone. Clipping does not make a headphone sound brighter.
This doesn't really make much sense. Generally larger drivers are made for more excursion, now this may not hold true for Headphone drivers, sense the driver is so close to the ear a high excursion can be heard as distortion or can cause damage to the ears(certainly if the headphone design is that of a closed back setup). But if were speaking about raw drivers in general then i cant agree. For Example; Subwoofers,midbass drivers, even SOME tweeters(long range), follow the principle of a high excursion rate. Subwoofers design go for large drivers/high excursion, and a balance between SQL and SPL generally is to have the Xmax relative to the size of the driver at a given power demand. Stiffness in most cases adds to the reliability of the excursion and helps the control, stiff drivers are meant to control power so that you do not easily damage the coil, this is a very common practice in driver dynamics. But most notable is the fact the stiff suspension is made for longevity, as with prolonged use the suspension will start to become looser and within age you will hit a point where the driver is at its optimal performance, correct? The whole reason behind brake-in periods.In reality it could not even be a problem of the drivers but maybe be of the source sound, many songs, and sounds we listen to do not even venture in to the subsonic bass we associate with subwoofers but are simply low midbass around 60-250hz(30hz maybe). And these Sony's are fairly good at clarifying what it is you are listening to at least the ones i have heard(the Qualia 010 and sa5000's are what im looking for). The problem for me is not the bass but the control of the "brightness". which i can only associate with undercutting.
More excursion means more distortion - but it usually means more output too, and modern speaker designers are trying to cheat hoffman. It never works, but don't tell them that.
Basically the ideal driver doesn't spend a lot of time moving in and out, but to get loud (and to hit low) you need displacement, and big speakers aren't sexy. So they roll the dice. Some designs work out fairly well (but end up insensitive or with limited extension), others not as much. The idea behind large drivers in a headphone is lower excursion, lower distortion, and a larger wave-front reaching the ear. Same reason planar designs are "good."
The ideal sub or bass driver is large and doesn't move in and out much - means faster recovery, lower distortion. Most headphones get this down pretty well because they don't have to get very loud (relatively speaking). The SA5k are among such headphones.
Getting back into the SA5k's though, as shown on page 2 of this thread, someone showed a picture of the Driver and a key feature is the rather deep concave of the cone Surround, as well as the material which should yield much more impact and excursion, more than enough to produce ample midrange/midbass over the rather powerful highs. Both the sa3000 and ex-1000 lack midbass when under powered yet yield a high level of highs regardless of the source. I can only assume the sa5000 follow in this practice.
They still fart if you eq it too aggressively (any headphones will - they just get to a point where you're asking the system to deliver something it can't). The enclosure has a lot to do with the voicing but so does the driver itself. In other words, if you had an accurate model of the SA5k drivers, you could probably make them bassier in a different enclosure, but there will still be an excursion limit or otherwise a wall where they just won't give you any more bass (especially *clean* bass). Sure, under-driving at low levels will result in less bass (perceptually), but overall we're just talking about a headphone that will never be a bass banger. That's just how they are - and there is nothing at all wrong with that.
Overall they need a clean amplifier more than a powerful amplifier, and if Sony's specs are to be believed, they can take a relatively large amount of input power as either a peak or instant burst. Which means they should be pretty robust and survive accidental volume boosts or relatively aggressive (but still within reason) equalization. This means you can absolutely address whatever concerns you want (within reason), and still have a good sounding headphone. As always, it's best to cut as opposed to boosting, as it does not risk clipping from the preamp/EQ into the amplifier, or asking too much of the driver. And generally you can accomplish the same results.
And again, no hard feelings intended, and I do hope you don't feel that I'm meaning to "Argue" with you.
