I need a headphone recommendation

The problem is more likely with your headphone amp's output impedance rather than with the headphones specifically. A dedicated headphone amplifier might be the solution, although it might cost more than a new pair of headphones. They'll typically have a lower output impedance than the ones built into interfaces. First step is to look up the impedance of your preferred headphones and choose a headphone amplifier based on that.

It looks like the headphones I was using (Sony 7509) run at 24 Ohm. 
 
So, would I benefit from cans with higher Ohms?
 

Your Sony's should sound quite loud compared to 600 Ohm headphones. The Sony's are pretty good phones too, I think you're only going to get a slight performance upgrade using higher end phones.

Rimshot
ATH M-50's but you need some normally good power. I like them much better than the AKG 240's.

+1 Those bad boys are LOUD. I run mine through a HC 6 off my RME UFX Interface. Killer Diller for sure. And they are Sonarworks compatible. 

There aren't a whole lot of manufacturers who offer high-impedance, high-fidelity headphones. However, when you get up into the stratosphere of high-end cans, they're nearly all high-impedance.
 
Beyerdynamics' excellent DT880 (semi-open) is one of the few mid-priced hi-z models, and it's actually available in 3 impedances, including 600 ohms. (The company also makes a well-regarded headphone amplifier with switchable output impedance - for a couple grand!.)
 
Impedance matching is nearly as important for headphones as for speakers in general. You wouldn't hook up 4-ohm speakers to your 16-ohm P.A. amplifier and expect optimal performance. (You might even blow up the amp!) Like speakers, headphones are current-driven devices. The lower their impedance, the greater the current required of the amplifier. High-impedance headphones are more efficient, with more windings (smaller wire) in their voice coils so that it takes less current to generate the magnetic field. So yes, higher-impedance cans might be a better match for your interface's headphone amp.
 
The downside is that if you ever want to use those hi-z headphones with your portable music player or smartphone, they might not perform as well because portable devices operate at lower voltages.
 
 

Thanks Bit. 
 
These two statements seemed contradictory:
 
"The lower their impedance, the greater the current required of the amplifier."
 
and

 "The downside is that if you ever want to use those hi-z headphones with your portable music player or smartphone, they might not perform as well because portable devices operate at lower voltages."
 
What did I miss?
 

Thanks again bit! I'm wondering if waiting until I can afford a nice set like those DT880s is the way to go, rather than add another mid-line headphone to the group.
 
pwalpwal - now THAT would be awesome. :)

smallstonefan
Thanks Larry - I'm leaning to the ATH-M50x since it has a Sonarworks profile. The Akias look like a good deal but it doesn't have the Sonarworks support...

The Akai ARE low impedence...and can be used with devices Small...
and they won't require Sonarworks...they are pretty flat right out of the box.

I bought them to compliment my ATH-M50's...

I really like them...but they are not High Impedence, as bit said...

Now...Newegg has Beyerdynamic DT-770 Pro's for $110 right now...
http://www.newegg.com/Pro...F-00D2-00002-_-Product

cclarry

smallstonefan
Thanks Larry - I'm leaning to the ATH-M50x since it has a Sonarworks profile. The Akias look like a good deal but it doesn't have the Sonarworks support...

The Akai ARE low impedence...and can be used with devices Small...
and they won't require Sonarworks...they are pretty flat right out of the box.

I bought them to compliment my ATH-M50's...

I really like them...but they are not High Impedence, as bit said...

Now...Newegg has Beyerdynamic DT-770 Pro's for $110 right now...
http://www.newegg.com/Pro...F-00D2-00002-_-Product

The KRK's are suppose to be extremely flat also but I noticed a huge change in the sound and improvement in my final mixes...   ears... mine and others said it all to me.  

The MPC headphones must have been discontinued.  They  are no longer available at AMS or zzounds.  Good news is that I bought them when they were available, and I agree with cclarry that they were a quality steal at the sales' asking price.

OK, so the DT 990 Pro 250Ohm headphones came in today. Wow, they really hype the high end - HOWEVER, with Sonarworks they are golden!!! I could mix with these. Also, listening to some Pink Floyd using Sonarworks for correction is pretty damn cool - you can really hear the separation of each instrument, and the reverbs involved. Personally, I like these much better than the 770s...
 
I'm now good to go - thanks to all for the info.

James, how about posting the correction curve for the DT990's? I'm curious to see what frequencies are hyped, according to Sonarworks.
 
Here's what head-fi.org shows, a significant peak at ~8.5KHz. Actually, I'd describe it as a broad upper-midrange dip, but the graph uses the usual 1KHz reference.
 
 
BTW, all you have to do is browse a few headphone frequency response graphs to dispel the notion that any headphones are "flat".
 
 

Wow, indeed. That shows a nearly 12dB spike at 9.5 KHz. Yeh, if that's accurate then I'd definitely say it qualifies as "hyped".
 
The differences between the two measurements can be chalked up to variances between tested headphones and smoothing. Smoothing refers to the number of FFT bins, or width of frequency bands reported. A graph with no smoothing is almost useless because it shows too much detail, much of it irrelevant. At the other extreme, too much smoothing hides imperfections, a common practice among marketers to make their products look better than they really are.
 
Just one of the reasons frequency-response charts are to be taken with a sodium chloride crystal, and best used to reveal general observations rather than as the sole determiner of quality.

No, I do not believe in headphone/speaker break-in.
 
There is no technical reason why it would ever be necessary, at least not with any quality speakers. There are some reasonable theories that say a speaker becomes more pliant after being exercised, but the time needed for that is about 10 seconds. Quality speakers will get that at the factory. 
 
I do, however, strongly believe that we subjectively grow to like the sound of headphones or speakers the more we listen to them. That could be the origin of this persistent myth.
 
Here are a few relevant links, if you're interested in learning more about this.
 
Speaker burn-in:
http://www.audioholics.com/education/loudspeaker-basics/speaker-break-in-fact-or-fiction
http://www.vikash.info/audio/audax/
Headphone burn-in
http://www.innerfidelity.com/content/evidence-headphone-break
http://www.wired.com/gadgetlab/2013/11/tnhyui-earphone-burn-in/