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NEWS: Meridian Releases The Explorer Pocket-Sized USB DAC - Page 33

post #481 of 999

Thanks for the correction, that's very informative.     After lookup the usb audio class,  yes, "Error detection via CRC, but no retry or guarantee of delivery."    Why it is designed this way is because they assume "if a packet or frame was dropped every now and again, it is less likely to be noticed by the listener."

(http://www.beyondlogic.org/usbnutshell/usb4.shtml)

 

Which means the quality of USB cable is important:       lost / corrupted packets are just skipped, and they hope user's won't hear the difference.

 

 

 

Quote:
Originally Posted by Clemmaster View Post

 

Currently, for USB Audio (even class 2), it is not ;) It is a common misconception: USB Audio Class 1.0 & 2.0 deal with isochronous endpoints, which does not feature error correction.

 

The S/PDif features a low-level protocol that splits the audio into frames, sub-frames and time-slots.

 

USB audio does not feature re-transmission or error correction. Only the bulk transfert mode allows for error correction (mass storage devices). The Musiland convertors (Monitor 01 & 02) are the only USB devices I know that don't relie on the isochronous transfert mode (as found in all synchronous, adaptive & asynchronous converters). They rely on the bulk transfert mode and require specific drivers (not USB Class complient).

post #482 of 999
Quote:
Originally Posted by Clemmaster View Post

The Musiland convertors (Monitor 01 & 02) are the only USB devices I know that don't relie on the isochronous transfert mode (as found in all synchronous, adaptive & asynchronous converters).

 

Now that I think of it, audio interfaces like the M-Audio Fast Track might also feature a different endpoint (bulk?).

 

Anyway, there's no apparent need for error correction. Even adaptive endpoints can sound really good already (e.g. USB-32 or even the Tenor 7022L in my Fostex HP-A3).

post #483 of 999
Quote:
Originally Posted by netdog View Post

Can anyone answer this question about USB error correction authoritatively?  We're just getting different people saying different things.  I'd love to see a reliable reference.

This thread is worth reading: http://www.head-fi.org/t/565791/on-usb-cables-and-controller-transfer-modes-a-series-of-questions-to-replies-from-usb-org

The guy asked the admin of usb.org

 

In short: short is better, jitter is not caused by cable, errors (not received bits) are detected but not recovered, bit flips are highly unlikely, any cheap USB certified cable will do ... all assuming normal home/office environment and properly designed hardware (which I hope the Explorer is)

post #484 of 999
Quote:
Originally Posted by jkbkot View Post

Hi, I have tried the Explorer with Ubuntu 12.10. It seems to work out of the box but the volume was very low even though the volume control was set to 100%.

 

Meridian says you need ALSA >= 1.0.32

 

...

... just an update: the Meridian website now states that only Alsa 1.0.23 or greater is required: http://www.meridian-audio.com/en/collections/products/explorer-1000/4/specification/

 

So it seems like the Explorer is working with Ubuntu 12.10 (that is Alsa 1.0.25) already as it should. And it does work but I'd expect more of it, I hear only a slight improvement over the default soundcard in my ThinkPad (T420 and T530). But I suspect that's because I only have 44.1/16 source files and maybe because I might not exactly be into the "Shure sound signature", as they put it, of my new Shure SE315 (~30 hours burn in). There's too many unknowns as I'm new to all this. 

post #485 of 999

Can this thing power low impedance IEM's (such as the 8-ohm Sony XBA-4) without adverse effects?

post #486 of 999

Nice looking product

post #487 of 999
Quote:
Originally Posted by netdog View Post

 

 

PS: I think the HD-6xx or the HiFiMan 400s are about as expensive as I'd like to get, unless I am really getting a big boost for the mega money that I see CAN be spent on cans.

 

 

The HD 600 sounds like a good idea to me.  Haven't had a chance to hear it yet (but will soon), the 300+ Ohm impedance of them will pair much better with the 40 Ohm output impedance of the ME than the 50 Ohm impedance of the HE500.

post #488 of 999
Quote:
Originally Posted by Tyll Hertsens View Post

 

 

The HD 600 sounds like a good idea to me.  Haven't had a chance to hear it yet (but will soon), the 300+ Ohm impedance of them will pair much better with the 40 Ohm output impedance of the ME than the 50 Ohm impedance of the HE500.


Tyll please correct me if I'm wrong - don't orthos have less problems with impedance curves?

post #489 of 999

TAS are at it again - after proclaiming first the Dragonfly, then the ME as their budget king in this particular niche, they would seem to have adopted a new standard bearer:

 

http://www.theabsolutesound.com/articles/hrt-microstreamer-pocket-rocket/

 

I know - Neil Gader - but if they keep this up I could well have whiplash by July  ;)

post #490 of 999

Umm...do any Head-fi'ers know if either the Meridian or any of its competitors like the Audioquest Dragonfly that work on Windows Vista?

post #491 of 999
With service pack 1, I think the Explorer will run just fine under Windows 7, I.e. Vista.

It's okay with XP and Windows 8 too.
post #492 of 999
Quote:
Originally Posted by DTrewwye View Post


Tyll please correct me if I'm wrong - don't orthos have less problems with impedance curves?

 

They have less problem because they have (almost) purely resistive impedance, which means the impedance of the planars does not (or barely) vary with frequency. Hence, their frequency response is consistent regardless of the output impedance of the amp driving them.

So, the 500s won't have the funky frequency response of the dynamic or (worse) BA iems (with their complex crossover network) when paired with high output impedance amps.

 

That being said, the planars are still subject to electrical damping. The 1/8 rule still applies and the HE-500 might not have the tightest bass or smoothest treble with the ME.

post #493 of 999

Not sure if I quite understand the issue of the high output impedance of this device but am I right in thinking that what it is means such low impedance or efficient full size cans like the Samson SR850 would not match well with this device?

post #494 of 999
Quote:
Originally Posted by Suopermanni View Post

Not sure if I quite understand the issue of the high output impedance of this device but am I right in thinking that what it is means such low impedance or efficient full size cans like the Samson SR850 would not match well with this device?

 

The low impedance of your can is the problem. The efficiency is not relevant to the ME's output impedance potential problem (the efficiency is more related to the ME's power output, but it's not an issue here).

 

If the Samson SR850 have a (relatively) flat impedance response across the audible range, then the high output impedance won't change the "intended" (original) frequency response of the cans.

If their impedance response varies a lot with frequency (as occurs on Balanced-Armature IEMs, which have cross-over network with complex impedance, that by nature, varies with frequency), then the intended frequency response will be modified (in general, for the worst, but not always).

 

The amp's output impedance also determine electrical damping. Simply put, the higher the damping factor, the quicker the driver "reacts" (= the more the amp has control over the driver). If the damping factor is too low, the driver will be "loose" and bloom will occur (e.g. in the bass).

The damping factor is defined as DF = Zcan / Zamp. As rule of thumb, DF should be >8. Which means, if the amp has an output impedance of 50R, the can should have an impedance of (at least) 400R.


Edited by Clemmaster - 3/5/13 at 7:27am
post #495 of 999
Quote:
Originally Posted by Clemmaster View Post

 

The low impedance of your can is the problem. The efficiency is not relevant to the ME's output impedance potential problem (the efficiency is more related to the ME's power output, but it's not an issue here).

 

If the Samson SR850 have a (relatively) flat impedance response across the audible range, then the high output impedance won't change the "intended" (original) frequency response of the cans.

If their impedance response varies a lot with frequency (as occurs on Balanced-Armature IEMs, which have cross-over network with complex impedance, that by nature, varies with frequency), then the intended frequency response will be modified (in general, for the worst, but not always).

 

The amp's output impedance also determine electrical damping. Simply put, the higher the damping factor, the quicker the driver "reacts" (= the more the amp has control over the driver). If the damping factor is too low, the driver will be "loose" and bloom will occur (e.g. in the bass).

The damping factor is defined as DF = Zcan / Zamp. As rule of thumb, DF should be >8. Which means, if the amp has an output impedance of 50R, the can should have an impedance of (at least) 400R.

 

 

So what cans would fare well with the Explorer as I already have it?


Edited by netdog - 3/5/13 at 7:48am
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