Headphones at home

2007-02-20 14:43:29

I am looking for a set of mid quality headphones for use with a EMU 1820 internal sound card.

I did some searching and have a short list:
Sennheiser HD555
Grado SR125
Grado SR225 (maybe)

These headphones would be Primarily used for critical listening to audio files (rock, soft rock, jazz & folk) and secondly for gaming or maybe in place of home surround sound system (but this has less focus for buying).

I understand that the Grado's have a mid-range preference in their delivery and that MAY be of benefit to me with my type of music, but my question here is more on the specifications and technical side.

Which of these (or other suggestions in the same quality range) would suit the EMU 1820 better? or is there any real diff?

I could use a thumb-nail lesson in the theory of matching impedance of headphone/speakers to the out put device, and any other 'matching of specs'.

Here are some of the EMU 1820 specs:
Headphone Amplifier
         Type: linear power amplifier
         D/A converter: CS4392
         Gain Range: 85dB
         Maximum Output Power: 50mW
         Output impedance: 22ohms
         Frequency Response (20Hz-20kHz): +0.0/-0.35dB
         Dynamic Range (A-weighted): 112dB
         Signal-to-Noise Ratio (A-weighted): 112dB
         THD+N (1kHz, max gain)
                        - 33ohm load: -70dB (0.032%)
                        - 600ohm load: -85dB (0.006%)
         Stereo Crosstalk (1kHz at -1dBFS, 600ohm load): < -100dB

Thank you for your time.

Headphones at home

Reply #1 – 2007-02-20 18:05:44

I only know a little bit about impedences, so someone else may correct me on this, but I'll tell you what I'm certain of:

First, either set of headphone will work with that amplifier.  You only have to be worried when headphones have a lower impedence than the amplifier's rated impedence.

Second, the Sennheiser's have a much higher impedence than the Grados.  This will generally translate into lower volume for the same setting (the reality is that sensitivity also plays a role in volume production, so higher impedence isn't the only rule to follow). 

Looking at the numbers, I think that this particular amplifier has enough juice to either headphone plenty loud enough for you.

Headphones at home

Reply #2 – 2007-02-20 18:27:37

One issue could be loudness. I have the 1820m and when I use it with my headphones (which are less sensitive than anything else on the market) I have the volume only slightly above zero. If they were more sensitive adjusting volume via the analog control would be problematic. And there would also be the risk of channel imbalance near zero. Not an issue for me but that's just because I have very inefficient headphones.

The output impedence does look quite high. Probably it would not work especially well with low impedance headphones. You would get a changed frequency response.

Headphones at home

Reply #3 – 2007-02-21 16:00:59

Thanks guys, that was the sort of stuff I was after.