How important is

[cmk 0]

amp > hp impedence matching?

 

OR

 

How does varying headphone impedence affect sound quality? Specifically which range of frequencies are affected more, treble/bass?

[red_ryder 0]

Great question. When I vary the impedance of the Spark HA-1A, it just changes the volume. Can't detect any change in bass or treble.

[Rameish 0]

red_ryder,

 

Really? What cans are you using? Hmm...to me the higer impedence sound fuller/lusher. So for some cans it may be a bit too much and a lower impedence is called for.

 

 

CMK,

 

Increasing the output impedence has a greater effect on some cans while on others the effect is subtle. There's no way of knowing prior to pluging it in as to which cans will alter their sonics dractically.

 

As you go higher you should also experience less top end and a bigger bottom end.

[red_ryder 0]

Rameish, I'm using DT931. Maybe it's just my ears not being sensitive enough to detect any significant change in the sound.

[cmk 0]

While the changes maybe subtle in some cases, I believe that they do make a difference if you can use more of the vol pot between the 10-2 o'clock range.

 

The reason I asked this question, was because I don't know whether there was a direct co-relation between the highs/lows and impedence.

 

Over the past couple of days, I have been experimenting with the 120ohm adaptor with the AT W100 and the Melos. The W100 being a low impedence design, I could only get the vol up to 9 o'clock at most, cos' it was pretty loud already. With the Beyer DT990, I had to go up to 11-12 o'clock to get the same SPLs. The impression I had was that the Beyers were more detailed than the W100, which was a bit perplexing, cos' I liked the W100s a lot.

 

With the 120ohm adaptor, I could now push the vol up to about 10-11 o'clock and the sound quality improved noticeably. The music was allowed to flow more smoothly and the details are back. More importantly, the reason why I liked the W100 seemed to come back again - its musicality. The only problem being that the 120ohm adaptor is an 1/8" plug, while the W100 and the Melos are both 1/4", so I've got 2 sets of adaptors - not an elegant solution.

 

I'll be doing some more listening to confirm my findings, and then make a final decision on my next move.

[lekguan 0]

With my DT931, 120ohm in place tames the treble, increases fullness, increases weight, and makes the cans more laidback(relative).

 

CMK: My guess would be that with the 120ohm in place, the volume seems lower because

1) The volume is really lower

PLUS some of 2) the cans are more laidback, thus making them seem softer.

As such, to reach what-you-feel is the same volume, you turn up more, as such it appears more detailed, but in fact its because the volume is louder. YMMV

[av98m 0]

You can get someone to diy you a 120ohm adapter cable with a 1/4inch plug.

[Charismatic 0]

I have the 120 ohm adaptor also, it lower the volume. I tried it with senn600 and turned up the volume and I hear no difference.

 

I tried it with sony dj700, turn up the volume, it sounds darker(more quiet) and the bass less bloated and I get more details. Overall sound wise, well, it still a dj headphone

[cmk 0]

As Rameish mentioned to me, it depends on the impedence of the can in question. If the can's impedence relative to the adaptor is 1:3 or more, then there will be an audible impact. So the 120ohm adaptor will work with cans around the 40ohm mark, ie low impedence cans.

 

lekguan, the level of detail due to the different position of the vol pot is a well documented one. Almost all vol pots sound their best in the 10-2 o'clock position. The vol pot is an attenuator - ie it cuts the output to the amplification stages. Depending on the quality of the pot, this is always detrimental to sound quality in varying degrees. So the less attenuation there is, generally the better.

 

Currently the plan is to have one of the outputs on the Melos loaded with a 150ohm resistor, and upgrade the parts and replace whatever needs to be replaced.

[Rameish 0]

Well, sonic changes do occur up to 3 times the impedence of the can in question. Anything more and all you should get is attenuation without further sonic changes.

 

As to why some people hear the differences while others don't, I really have no clue.

 

It would be stange indeed for the makers of Spark HA-1A to include this if it were redundent.

 

Actually the 931 is the one can that does exhibit quite a change when you increase the output impedence on my Corda. I will try it with the 931 when I have some spare time.

 

Cheers

Rameish

[hacknet 0]

technically, the higher the impedance of the cans the better the bass since DF goes up and current consumption drops. all in the favour of speedier punches.

[Firefox 0]

technically, the higher the impedance of the cans the better the bass since DF goes up and current consumption drops. all in the favour of speedier punches.

I doubt current consumption is a factor when it comes to headphones since most dedicated headphone amps can deliver sufficient current to the cans at nominal listening volumes. Perhaps this is more of an issue with speakers.

If anything, lower impedance cans seem to have better bass response than high impedance cans. Most of the former also sound faster.