[Yaozilla]

I just got the Sennheiser hd650 in the mail and tried them out and am kinda dissapointed. Im only using the stock soundcard on my computer for now until I get an amp but the sound quality isnt that great and the sound is too low compared to my grado sr 125. My grado sr125 sound very loud with the stock sound card on my computer and the volume on the hd650 is too soft.


I do plan on getting an amp but im wondering why the sr125 actually sound better without amp.


Sorry for being a newb. I just got into headphones 3 months ago

 

[paaj]

Grado's in general are much easier to amplify. The Sennheiser needs a lot more power than your soundcard can deliver. Not just to get the right volume, but also for example to tighten the bass.

They have a very different sound signature and better will always be subjective, but the SR125 comes much closer to it's potential than the HD650 will in this situation.

To get started, you could see if you have a receiver/stereo-amp around and then connect your pc to one of those. They often have more of the power necessary and are not so expensive to find second-hand.

 

[tygger]

In this hobby numbers and graphs are normally useless, but some basic headphone arithmetic is still helpful to some extent.
Look at the specs of your cans. The Grados have an impedance of 32 Ohm and sensitivity of 98 dB/mW. This means they require 1 mW of power to produce 98 dB of sound level. Senns are 300 Ohm and 103 dB/mW. To drive Grados to 103 dB they will require ln(103 - 98) ~= 3.16 mW of power.
In reality, what Sennheiser calls impedance is electrical resistance. Impedance of HD650 varies across the spectrum of sound frequencies in the range of 320 - 480 Ohm. Let's assume it to be 320 Ohm to make it 10x the impedance of Grados. To produce 103 dB (very loud sound), Grado need SQRT(3.16 mW x 32 Ohm) ~= 320 mV of voltage from the sound card. HD 650 would theoretically require almost twice as much - 570 mV. In reality, the sound card output voltage would need to be even higher.
Real world audio mathematics is much more complicated, this is just a needed minimum to avoid issues like yours.
Get an amp or get rid of HD650. These cans are not for use with onboard sound.

 

[TwoTrack]

Very interesting...