[dgbiker1]

I felt the exact same way when I first heard mine. Disappointing bass and painful ~8kHz range (this includes sibilance). My first recommendation to you is to download pink or white noise files and run your K701 with them almost 24hrs a day, giving them an hour rest every once in a while. You'll see them change dramatically pretty quickly.

If you're listening to them straight out of an MP3 or CD player or laptop... don't

These things NEED a good amp. Even my CMOY amp that dramatically improved the Grados couldn't drive these phones properly. My experience with the K701/tube amp was very positive, the tubes help smooth them out a bit.

Finally, these things are notorious for needing long burn-in time. You can expedite the process by running them constantly, but they really sound much better over time. I ran them with pink noise overnight the first day I had them and the bass was much better the next day. About 100 hours in they're no longer sibilant, but still a bit peaky around 8kHz though that characteristic is balancing out. My test record for these phones is Within Temptation's The Heart of Everything. The singer's voice and much of the music seems to be in that 8kHz range, I literally could not listen to the record at any volume when I first got the K701, it was absolutely painful. The combination of burn-in and a better amp has allowed me to listen to the record at the higher end of comfortable listening levels. Until you reach that point, I recommend sticking with acoustic music

 

[mugtastic]

i'm running this same combo with plenty of burn in by now - sounds great!

i wouldn't want to use the k701s without a proper amp.

(btw - no one need apologize for an ipod w/porta-pros - awesome combo!)

 

[One Fan To Another]

Thanks for the encouraging replies. I will keep these running with pink noise for at least 100 hours before passing real judgment.

I do have a little CMOY amp but I'll look into other amps (I'm using an audio interface as the main out). I have enough audio equipment that it wouldn't hurt to add a proper headphone amp at this point.

Just curious: With all this talk about needing good amps to get good sound out of high end headphones are there any high end headphones that sound good without an amp? I mean if a pair of Porta-Pros can get satisfying sound out of an MP3 - for $60 - then what's the deal with the bigger stuff? I guess in comparison; do the Sennheiser HD650s need a good amp to sound good?

EDIT: Oh, and on a side note: How come professional reviews of these headphones are so overly positive if they are using them straight out of the box? With a well burned in pair aside I'd give these cans a pretty low score if I was rating them based soley on the straight out of box 'without tube amp' sound.

 

[dgbiker1]

Quote:

Originally Posted by One Fan To Another /img/forum/go_quote.gif Thanks for the encouraging replies. I will keep these running with pink noise for at least 100 hours before passing real judgment. I do have a little CMOY amp but I'll look into other amps (I'm using an audio interface as the main out). I have enough audio equipment that it wouldn't hurt to add a proper headphone amp at this point. Just curious: With all this talk about needing good amps to get good sound out of high end headphones are there any high end headphones that sound good without an amp? I mean if a pair of Porta-Pros can get satisfying sound out of an MP3 - for $60 - then what's the deal with the bigger stuff? I guess in comparison; do the Sennheiser HD650s need a good amp to sound good? EDIT: Oh, and on a side note: How come professional reviews of these headphones are so overly positive if they are using them straight out of the box? With a well burned in pair aside I'd give these cans a pretty low score if I was rating them based soley on the straight out of box 'without tube amp' sound.

I'll go in reverse order. The "professional" reviews I've read did burn them in. Stereophile for example specifically mentioned how mediocre they sounded when he first heard them at a show, but was blown away by a properly burned-in pair. Other don't mention it, but they might have review units that get passed around or just don't mention the burn-in.

Sennheisers will also need a good amp because of very high impedance ratings. Grados do pretty well without an amp thanks to 32 ohm impedance. Other than a volume increase, the detail on SR225s didn't change much between the ipod headphone jack and headphone out>cmoy, going through the ipod line-out made a much bigger SQ difference.

I would guess the reason higher end headphones are more amp dependent is that they get stiffer driver assemblies to keep the sound better controlled (higher natural frequency, more controlled damping ratio, more pistonic diaphragm motion reduces unwanted harmonics) as opposed to relatively loose, floppy diaphragms that are easy to vibrate but not well controlled or damped. Stiffer diaphragms need more force to displace, therefore the magnet coils need more current to provide adequate force, meaning the amp needs more juice. My driver design education only goes back about 2 months since I started my ME-525 Acoustics course, so I will probably be missing something, but I could ask the professor on Friday

 

[pataburd]

Quote:

Originally Posted by dgbiker1 /img/forum/go_quote.gif I'll go in reverse order. The "professional" reviews I've read did burn them in. Stereophile for example specifically mentioned how mediocre they sounded when he first heard them at a show, but was blown away by a properly burned-in pair. Other don't mention it, but they might have review units that get passed around or just don't mention the burn-in. Sennheisers will also need a good amp because of very high impedance ratings. Grados do pretty well without an amp thanks to 32 ohm impedance. Other than a volume increase, the detail on SR225s didn't change much between the ipod headphone jack and headphone out>cmoy, going through the ipod line-out made a much bigger SQ difference. I would guess the reason higher end headphones are more amp dependent is that they get stiffer driver assemblies to keep the sound better controlled (higher natural frequency, more controlled damping ratio, more pistonic diaphragm motion reduces unwanted harmonics) as opposed to relatively loose, floppy diaphragms that are easy to vibrate but not well controlled or damped. Stiffer diaphragms need more force to displace, therefore the magnet coils need more current to provide adequate force, meaning the amp needs more juice. My driver design education only goes back about 2 months since I started my ME-525 Acoustics course, so I will probably be missing something, but I could ask the professor on Friday

After 300+ hours, the K701 sounded like a completely different set of headphones to my ears compared to their first 20-50, or even 100-200, hours. With only the stock cable, I began to prefer the K701 to my prior reference, the RAL re-cabled Ultrasone Proline 750--a really enjoyable set of cans in their own right (and #2 on my list of alltime favorites).

Beyond SR-225 on the Grado line (i.e. SR-325i, MS-2i) the positive effects of a good, dedicated headphone amp become quite evident, IMHO. Moving from a JVC mini-component headphone out to the EVS-modded Oppo 970HD/Bada PH-12 combination made the SR-225 sound better; but the 325i sounded much, much, much better.

BTW, I have had very good success pairing the K701 w/the Darkvoice 336i all-tube (1x 6AS7G & 1x 6SN7) amp, and even better success w/the Bada PH-12 hybrid (3x 6SN7 & 2x Toshiba 2SK1529 mosFET) amp.

With the Revelation Audio Labs (Paradise Cryo-Silver Reference) re-cable, nothing I've tried so far among the AKG's popular peers has come close to the performance of the RAL/K701.

 

[soundfreq]

thanks for the review. was thinking of getting a new headphone, maybe the k701 is it

 

[Rednamalas1]

Quote:

Originally Posted by soundfreq /img/forum/go_quote.gif thanks for the review. was thinking of getting a new headphone, maybe the k701 is it

It'll be a totally different experience from your HD650s and D5000s

 

[soundfreq]

Quote:

Originally Posted by Rednamalas1 /img/forum/go_quote.gif It'll be a totally different experience from your HD650s and D5000s

yup, that was what i was thinking. the upgrade bug just got me again

 

[greggf]

time to try the K701 - again -