Hi all,
 
I have various headphones and Sonarworks and they have all served me well. However, last night I started playing around with some ambient stuff and found that sound design of subtle evolving pads in a mix of other things can't easily be done on my Adams and my headphones are "too weak".
 
I need a good pair of closed or semi-closed that have some real volume to them. I am using my UAD Apollo interface's headphone amp.
 
I also want a pair compatible with Sonarworks.
 
what to do?

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.

Thanks Bit. The Apollo manual says:
 
Maximum Output Power is 80 milliwatts into 600 Ohms 
 
Now, I'm off to try and find out if that is good or bad...

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

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

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.

Rbh
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.

Thanks, that's good to know! These were expensive headphones back when I bought them, and I love them. I wish there was a Sonarworks profile for them...

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. 

I think you want "clarity" rather then "loud"...

These bad boys are flat and really clear...50mm drivers and won't break the bank...

http://www.zzounds.com/item--AKAMPCHDPHNS
 
they're built like a tank...and originally cost $499....and currently
sell for $199 just about everywhere, but are $69.99 
at zzounds and AMS....

Check out the reviews on them....

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.