Speaker and Headphone Choices for listening to Classical Music

[Mookalafalas]

I have a pair of Shure 840s, but am not that happy with their sound.  I would like to upgrade to the Sennheiser HD 598 (which I saw several people hear swear by), or, perhaps, the Sennheiser HD 650s. Has anybody compared the two?

[petrarch]

I like neutral but don't like cold, and therefore found that having a touch of warm tube sound in the chain goes a long way to satisfy my ears (and oh, the three-dimensionality it brings!).

[Mirror Image]

I have a pair of Shure 840s, but am not that happy with their sound.  I would like to upgrade to the Sennheiser HD 598 (which I saw several people hear swear by), or, perhaps, the Sennheiser HD 650s. Has anybody compared the two?

Haven't heard the HD 650s, but I would opt out for the 598s unless you really want to pay more money. I can't imagine much differences between these two headphones.

[mc ukrneal]

I have a pair of Shure 840s, but am not that happy with their sound.  I would like to upgrade to the Sennheiser HD 598 (which I saw several people hear swear by), or, perhaps, the Sennheiser HD 650s. Has anybody compared the two?

Do you use an amp? If not, the decision is easy - 598.

[DavidW]

I have a pair of Shure 840s, but am not that happy with their sound.  I would like to upgrade to the Sennheiser HD 598 (which I saw several people hear swear by), or, perhaps, the Sennheiser HD 650s. Has anybody compared the two?

The 650s sound better, they are warm and dark but very detailed.  They have an exceptionally deep sound stage too... but they are hard to drive.  The 598s have a slight bump in the upper mids, recessed treble and are also warm.  They are not as hard to drive as the 650s.  The 598s are not as detailed as the 650s, but the difference is subtle.  Most of what I hear between the two is tonal quality. 

The build quality on the 650s is far superior.  Series 6 cans and upwards use better materials, and are not as fragile as the series 5 cans which are prone to headband cracking.

[Brian]

Do you use an amp? If not, the decision is easy - 598.

Is there a significant difference between 598 with/without amp? I have headphones I'm satisfied with (ATH-M50s) but I don't know how significant the change in sound quality would be if I invested in amp+DAC.

[mn dave]

I have what are supposed to be decent headphones but if the cord rubs against clothing or whatever I can hear it scraping through the speakers. URGH!

[mc ukrneal]

Is there a significant difference between 598 with/without amp? I have headphones I'm satisfied with (ATH-M50s) but I don't know how significant the change in sound quality would be if I invested in amp+DAC.

In my opinion, no, but this is an area where people disagree. As DavidW already mentioned, the 650 is harder to drive, so you won't get the full impact without an amp. The 598, being easier to drive, shows much less of a difference, and I think most people would be quite happy with how it sounds without an amp. But having said that, most headphones benefit with the use of an amp.

Based on the specs I found for your ATH-M50, they look like they will be pretty good without an amp as well. You can try hearing the difference by plugging into your usual source and then comparing by plugging into a stereo system (yours or a that of a friend, or even taking it to an electronics store). If you don't hear any/much of a difference, you don't need one. The only advice I can give you is to try and hear for yourself (and then decide), because you will find opinions from all extremes.

[DavidW]

Is there a significant difference between 598 with/without amp? I have headphones I'm satisfied with (ATH-M50s) but I don't know how significant the change in sound quality would be if I invested in amp+DAC.

Both are low impedance headphones with relatively high sensitivity.  They don't need to be amped, and the sound wouldn't really change that much unless the amp is colored.

btw are the M50s neutral? I've been thinking about buying them.  But I read that they were more like loudness curve headphones (elevated bass and treble).

[DavidW]

fyi Brian if you can handle some math, I can give you a formula that you can use to calculate the necessary rms voltage to drive any pair of headphones.  Then you can solve for what your source provides and know if you need an amp or not.

[71 dB]

Sennheiser HD-598, which is my primary headphone at the moment has excellent imaging. The sound is more forward and less left/right. With proper crossfeeding the result is yummy! HD-650 is an older model, and has more of that left/right imaging to my understanding, but I haven't heard it. My older headphone was HD-580 (similar sound philosophy)

HD-598 is perhaps easy to drive, but it really needs low output impedance! Audio amps typically have far too high output impedance for this headphone. HD-598's impedance changes between about 60 and 275 ohms as a function of frequency. At 100 Hz is the impedance peak. Low output impedance (I'd say 10 ohms at most) is needed to keep the frequency response flat and damping factor high. The headphone output impedance of NAD 302 amplifier is 220 ohms. If we connect HD-598 to this amp, this happens:

L_min = 20*log10(60/(60+220)) = -13.4 dB
L_max = 20*log10(275/(275+220)) = -5.1 dB

Frequency response error due to high output impedance: L_max - L_min = -5.1 dB + 13.4 dB = 8.3 dB

This means a huge bass boost of about 8 dB around 100 Hz. Totally unacceptable! If the output impedance is 10 ohms, the math goes like this:

L_min = 20*log10(60/(60+10)) = -1.3 dB
L_max = 20*log10(275/(275+10)) = -0.3 dB

Frequency response error due to acceptable output impedance: L_max - L_min = -0.3 dB + 1.3 dB = 1 dB

Bass boost of this magnitude is acceptable if not ideal. If the output impedance is only 1 ohm, the frequency response error is only 0.1 dB. That's totally acceptable. Damping factor (headphone impedance/output impedance) should be at least 8. High damping factor means precise, distortion free sound. Low damping factor makes the sound distorted and lousy.

HD-650 isn't as sensitive to output impedance and since it's impedance is higher (300-470 ohms), high damping factor is easier to achieve.

[Mookalafalas]

Wow, thanks for all the excellent feedback.  It's a lot to think about.  BTW, when I use my CD player, I'll plug right into my receiver, and when I play off my hard drive, I'll use a headphone amp/Dac.

[DavidW]

Just wanted to point out that the iphone has a low output impedance (4.5 Ohms) as do many phones and mp3 players.  Headphone amps typically have less than 1 Ohm impedance. 

Not every amp and avr has a high output impedance.  Basically those that use resistors to step down the voltage from the speaker source will.  There are others that have dedicated circuitry for their headphone outs and output impedance is low.  I noticed that the former tend to have audible noise floors, and the latter tend not to.  So if the headphone jack sounds fine to you on your receiver, I wouldn't be concerned with the non-flat impedance curve.

[G. String]

Sennheiser HD-598, which is my primary headphone at the moment has excellent imaging. The sound is more forward and less left/right. With proper crossfeeding the result is yummy! HD-650 is an older model, and has more of that left/right imaging to my understanding, but I haven't heard it. My older headphone was HD-580 (similar sound philosophy)

HD-598 is perhaps easy to drive, but it really needs low output impedance! Audio amps typically have far too high output impedance for this headphone. HD-598's impedance changes between about 60 and 275 ohms as a function of frequency. At 100 Hz is the impedance peak. Low output impedance (I'd say 10 ohms at most) is needed to keep the frequency response flat and damping factor high. The headphone output impedance of NAD 302 amplifier is 220 ohms. If we connect HD-598 to this amp, this happens:

L_min = 20*log10(60/(60+220)) = -13.4 dB
L_max = 20*log10(275/(275+220)) = -5.1 dB

Frequency response error due to high output impedance: L_max - L_min = -5.1 dB + 13.4 dB = 8.3 dB

This means a huge bass boost of about 8 dB around 100 Hz. Totally unacceptable! If the output impedance is 10 ohms, the math goes like this:

L_min = 20*log10(60/(60+10)) = -1.3 dB
L_max = 20*log10(275/(275+10)) = -0.3 dB

Frequency response error due to acceptable output impedance: L_max - L_min = -0.3 dB + 1.3 dB = 1 dB

Bass boost of this magnitude is acceptable if not ideal. If the output impedance is only 1 ohm, the frequency response error is only 0.1 dB. That's totally acceptable. Damping factor (headphone impedance/output impedance) should be at least 8. High damping factor means precise, distortion free sound. Low damping factor makes the sound distorted and lousy.

HD-650 isn't as sensitive to output impedance and since it's impedance is higher (300-470 ohms), high damping factor is easier to achieve.

This post is amazing. Thank you.

So what happens if I use 598 with 32 ohm iPod and my laptop, which has output impedance of 32 ohms, too? Should I use something in between?

[DavidW]

So what happens if I use 598 with 32 ohm iPod and my laptop, which has output impedance of 32 ohms, too? Should I use something in between?

20*log(60/(60+32)) = -3.7 dB for Lmin, 20*log(275/(275+32)) = -.96 dB and the difference is 3 dB so it's a little bit off from bass to treble but nothing like 71 dB's example.  You could just use eq, but that bass boost is not a big deal and you might even like it.

The damping factor is another thing, but that is really an audio myth.  Speakers are well damped by design.  You don't really need the ratio of impedances to be greater than or equal to 8... but it wouldn't hurt either.

[Brian]

btw are the M50s neutral? I've been thinking about buying them.  But I read that they were more like loudness curve headphones (elevated bass and treble).

I'm afraid I don't have experience with a wide enough range of headphones to answer this properly; they were my first good pair. Bass presence is certainly stronger than what people seem to say about most other pairs.

[71 dB]

Just wanted to point out that the iphone has a low output impedance (4.5 Ohms) as do many phones and mp3 players.  Headphone amps typically have less than 1 Ohm impedance.

Well, 1-2 Ω or even less but cheapers models are around 5 Ω as far as I know. My old iPod Shuffle 512MB has about 2 Ω output impedance (I measured it).

Not every amp and avr has a high output impedance.  Basically those that use resistors to step down the voltage from the speaker source will.  There are others that have dedicated circuitry for their headphone outs and output impedance is low.  I noticed that the former tend to have audible noise floors, and the latter tend not to.  So if the headphone jack sounds fine to you on your receiver, I wouldn't be concerned with the non-flat impedance curve.

The irony is that the more powerful amp the more stepping down is needed, so low power amps have "better" headphone outputs. 

There is an easy solution to be done with high output impedance and noise floor. Make an extension cable (buy connectors and few meters of cable) for the headphones (that's a good idea anyway for mobility). Add two 10 Ω resistors inside the cable jack so that the resistors connect left and right signal to ground. Now the headphone "sees" 10 Ω output impedance instead of the higher output impedance (say 220 Ω) of the amplifier. Also, there is a significant drop of signal level, so the noise floor drops too, hopefully completely under hearing threshold. One has to turn the volume up, but that's no problem.

This is a "few bucks trick" and it works. You just need to be able to use soldering iron to solder those resistors and connector jacks to the cable.

Now, if you add a 3,9 mH coil with DC resistant of about 8-10 Ω between left and right channels, you have got an extremely simple crossfeeder that works! Even adding proper delays to the crossfed signals. So, two resistors and one coil with convenient DC resistance soldered into an extension cable

a) lowers output impedance increasing damping factor and making frequency response more flat
b) attenuates  noise floor, making it easily inaudible.
c) crossfeeds the sound all right (but better crossfeeders exist)

If that's not cool and cost effective, I don't know what is! 

This post is amazing. Thank you.

So what happens if I use 598 with 32 ohm iPod and my laptop, which has output impedance of 32 ohms, too? Should I use something in between?

Thank you!

Are you sure about 32 Ω? Well, there's a bass boost of almost 3 dB if you do that. That's audible. Also, the damping factor is rather low (60/32 is about  2).

iPod: I believe your iPod has an impedance much lower than 32 Ω. Anyway, maybe you should use a "portable headphone" with it? Like Sennheiser PX 200 II. Sennheiser HD-598 is an indoor headphone with very little isolation.

laptop: why not buying an USB DAC headphone amplifier? Fiio E7 for example?

[71 dB]

The damping factor is another thing, but that is really an audio myth.  Speakers are well damped by design.  You don't really need the ratio of impedances to be greater than or equal to 8... but it wouldn't hurt either.

Myth and myth. It depends on how damped the headphones are mechanically. If mechanical damping is low, the damping must be done on the electrical side. My understanding is that large over ear headphones like HD-598 have low machanical damping and high electrical damping is needed. In my experience damping factor matters. The sound is clearly more controlled when the output impedance is very low compared to high impedances.

small In ear/portable headphones probably have more mechanical damping, so electrical damping factor doesn't matter so much. Sensitivity of the headphones tell about mechanical damping. High sensitivity => low mechanical damping.

[G. String]

Are you sure about 32 Ω? Well, there's a bass boost of almost 3 dB if you do that. That's audible. Also, the damping factor is rather low (60/32 is about  2).

iPod: I believe your iPod has an impedance much lower than 32 Ω.

Yes. Almost all iPods are 32
http://support.apple.com/kb/SP572.
How should I get rid of that bass boost?

[71 dB]

Yes. Almost all iPods are 32
http://support.apple.com/kb/SP572.
How should I get rid of that bass boost?

Apple means headphones are 32Ω, not output impedance.

So, I believe the impedance of your iPod is much lower, 2-5 Ω. That means the bass boost is very small and doesn't matter.