Headroom MicroAmps: Driving Sennheiser 650, Denon 5000
Jan 24, 2010 at 4:16 AM Thread Starter Post #1 of 15

MoData

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Hi !
I've got both the headphones mentioned above, as well as the Headroom MicroAmp.

Here's what I notice:
I can drive the denons to paifully loud levels, almost without realizing it, but the sound quality remains awesome.

The Sennheise'rs start sounding awful even before they get too loud.
They sound good to about 9-10 Clock on the High setting. Anything louder, and I don't seem to like it too much anymore.

I understand that the Denons 5000 have an impedence of 30 ohms, and the 650s an impedence of 300 ohms.

Is it the headphones, or is the micro-amp running out of juice to power the headphone?
 
Jan 24, 2010 at 4:32 AM Post #2 of 15
Or maybe that's just the 650's Dark Viel everyone keeps talking about. :)
 
Jan 24, 2010 at 4:04 PM Post #3 of 15
I don't know what version/year your Micro Amp is but my 2006 with Desktop Module powers my HD 650 very nicely. My HD 650 has the double foam removal mod and it is not veiled but has the obvious warm sound signature...which I love.
 
Jan 24, 2010 at 5:00 PM Post #4 of 15
I know what you are talking about. it is the HD650,and not the amp.
the HD650 have farward mids (and also low treble) and they are pretty neutral headphone overall. in high volume levels their mids become too forward and this is why you probably don't like the sound of them. I also don't like them i fairly high volume levels.
i just want to mention that I appreciate them despite these accusations
normal_smile .gif



the denons are a different story since they have rather backward mids (more in the background,coming from a far) and attenuated bass, two factors that makes it more easy (and also very enjoyable) to listen in higher volume. truly an amazing headphones IMO.

I use both the denon and the HD650 with my ultra micro stack and the sound is always spectacular. the headroom amps are very powerful and dynamic.
 
Jan 25, 2010 at 6:49 AM Post #5 of 15
On the other hand, my ears hurt after hearing the denons. Probably because i hear them too loud. :)
 
Jan 25, 2010 at 2:58 PM Post #6 of 15
When you listen to audio above approx. 90dB, the "acoustic reflex" begins to kick in.

In brief, at high sound levels, the small muscles of your middle ear pull the bones that transport vibration away from the ear drum and oval window of the inner ear. The effect of the muscle contractions is to reduce the apparent sound level by as much as 20dB. But it also introduces noise and distortion of the sound due to the tensed muscles, so at some point in raising sound level the quality of audio perceived will be reduced.

I'm not sure you're playing your music too loud, and not sure this is what you're hearing, but it's likely. Listening at levels that have the acoustic reflex turned on all the time increases "listening stress" and can hasten the onset of tinitus.

Please be careful.
 
Jan 27, 2010 at 9:50 PM Post #8 of 15
9-10 o-clock on high?!? My Senns rarely get above 9-10 o-clock on MEDIUM before my ears start to complain and I get fuzzy hearing after.
eek.gif
They are very clear at lower/medium volumes on the Micro.
 
Jan 28, 2010 at 8:33 AM Post #9 of 15
Well, I guess it also depends on the strength of the source signal, no?
I feel that plugging it into the computer makes it go much clearer.
 
Jan 28, 2010 at 10:26 AM Post #10 of 15
Quote:

Originally Posted by moogoob /img/forum/go_quote.gif
9-10 o-clock on high?!? My Senns rarely get above 9-10 o-clock on MEDIUM before my ears start to complain and I get fuzzy hearing after.
eek.gif
They are very clear at lower/medium volumes on the Micro.



X2
 
Jan 28, 2010 at 4:49 PM Post #11 of 15
Quote:

Originally Posted by MoData /img/forum/go_quote.gif
Well, I guess it also depends on the strength of the source signal, no?
I feel that plugging it into the computer makes it go much clearer.



Hmm. You might have a point. I run from an Ultra Micro DAC plugged into my mac via optical - volume from the computer is therefore always full (optical disables the system's volume control) and the UM Dac is known to have a fairly robust (read: loud) line stage, so I might need less gain than you for this reason.

Hard to tell without a direct comparison, though.

EDIT: What source are you using? PC soundcard? If so, do you have ASIO installed?
 
Apr 11, 2010 at 6:19 AM Post #12 of 15
Finally got around to getting the MicroDac too. At this point, the sounds a lot better and I listen to it at a max of 9 0Clock.
Don't have the denon's anymore but thinking of acquiring them again.
 
Apr 11, 2010 at 7:11 PM Post #13 of 15
I don't get the obsession with using higher gain than necessary.

The volume pot is at its best either in the 12 o'clock region, or at completely open (100%). You should use the gain switch accordingly.

With a powerful source like the Micro DAC, there is absolutely no reason to use high gain with 650's.
 
Apr 15, 2010 at 2:55 PM Post #14 of 15
Not questioning your statement, just curious as to why you think high-gain is a bad idea.
Does it really matter?
 
Apr 15, 2010 at 5:33 PM Post #15 of 15
Quote:

Originally Posted by MoData /img/forum/go_quote.gif
Not questioning your statement, just curious as to why you think high-gain is a bad idea.
Does it really matter?



For exactly the reason I stated...

Volume potentiometers have optimal areas in their range where the balance between the channels is at its best. The point of the gain switch is to be able to optimise the gain setting to allow the use of the volume pot in its optimal range for normal listening levels. I.e., when it's set around 12 o'clock.
 

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