[GUIDE] Sonic Differences Between DT770-DT990 Models & More

[Chris J]

 
Quote:

I think we're saying somewhat the same thing, but making different assumptions or crossing our wires somewhere.
 
Assuming 96db @ 0.774 V (1V? something with a rms in there, whatever) is the same for all three impedance models, that gives us sensitivity @1mW:
32 ohm ... 81.05 db
250 ohm ... 89.98 db
600 ohm ... 93.78 db
 
Blah, way too tired to write anymore.
 

Hey there, back again.
Please understand, I'm not trying to start a war here, I'm just trying to think this thru........so here goes. This has been a very thought provoking discussion!
If you assume that sensitivity of all DT770/880/990 series is the same for all impedances then I agree with your numbers if sensitivity is 96 dB @ 1 Volt.
 
However:
I had assumed that efficiency is the same for all impedances of the DT770/880/990 series:  i.e. efficency is 96 dB SPL @ 1 mW.
Beyer is not too forthcoming with information, they state 96 dB and reference a CE spec:  EN 60 268-7.
I couldn't find anything on the web about this CE spec.
However Beyer does state that headphones with lower impedance ratings offer higher volumes than headphones with higher impedance ratings at the same level of input.
Beyer also states that high impedance headphones are designed for use with high output headphone amplifiers.
So this leads me to suspect that the 96 dB figure is in fact an efficiency figure.
In addition:  the specs for the T1 are: 102 dB at 1 mW which as you know is efficiency. So I guess the DT770/880/990 numbers are also efficiency.
In other words the same amount of power (i.e. the amount of work done) will give you the same SPL.
 
Take a look at this:
I crunched thru some figures and came up with:
32 ohms @ 1 mW = 179 mV, 5.6 mA
32 ohms @ 5 mW = 400 mV, 12.5 mA
32 ohms @ 10 mW = 565 mV, 17.6 mA
 
250 ohms @ 1 mW = 500 mV, 2 mA
250 ohms @ 5 mW = 1.12 V, 4.4 mA
250 ohms @ 10 mW = 1.58 V, 6.3 mA
 
600 ohms @ 1 mW = 775 mV, 1.29 mA
600 ohms @ 5 mW = 1.73 V, 2.89 mA
600 ohms @ 10 mW = 2.45 V, 4.0 mA
 
In other words, for an input of approx. 500 mV, the 32 ohm version will draw 10 mW and the 250 ohm version will draw approx. 1 mW.
The 32 ohm version would be approx. 10 dB louder than the 250 ohm version for the same voltage.
 
I plotted the voltage vs. power numbers on graph paper, plotting the independent variable, voltage on the X axis and the independent variable, Watts, on the Y axis.
Keep in mind that the output of a headphone amplifier is voltage and the power deleivered is a function of the output voltage and the headphone impedance.
When I plotted the numbers on log paper the the lines were parallel to each other.
In other words, for any given input voltage, a 32 ohm Beyer DT 880 will always be louder than a 250 or 600 ohm Beyer DT 880.
 

 

[Rawrbington]

i did some more testing,  and the 80 ohm does seem louder at the same position of the dial than the 32 ohm.
 
BUT, could this be due to different drivers between the premium and pro versions?
 
or the sound sig since the 80 ohm is bassier it may only appear louder?
 
or is it somehow involving the resistance, where maybe the amp pushes more voltage or something at a higher impedance?
im reaching here i know,  just wondering.  i do find it interesting.
 
however the difference is closer than i first thought.  they could be almost the same, however unless my ears are messed up its not possible that the 32 is louder.  they are either the same or as it sounds to me the 80 ohm is noticably louder at 9 oclock on the dial and even 11 oclock.
 
however the 600 ohm 990 is def not as loud as either at 9ish.  and then by 11 it gets a little screwy because my SS pioneer doesn't have the nuts for it

 

[tdockweiler]

Am I the only ones that find the Pro models more comfortable than those of the Premium models? I wonder why this is. It's as if the design of the Premium models just does not work with my head. It's as if when I wear them they press on and pull upwards on my ears. Strange huh? I bent the DT-770 600 a bit and now have a much better fit, but it's somewhat loose. The DT-770 Pro 80 is a perfect fit in ever way and the cups are not shallow. I could wear that thing all day.
 
Does anyone know if the DT-880 Pro has the very shallow cups like the 880 does? Is the foam area flat unlike the DT-880 Premium?
 
Since I'm loving this DT-770 600 so much I may try the DT-880 Pro with the hope they're more comfortable. DT-880 Premium was impossible for me to use for more than an hour. I think the comfort issues for me is mostly the design of the Premium versions. Something about the angle of the metal sides of the headband.
 
I'd also prefer a semi-open headphone. I have my doubts that the DT-880 Pro will have more forward mids than this pair, but we'll see.
 
Q701 and this DT-770 600 are not a good pair to buy at the same time. I can't figure out which one I like more! Q701 is definitely warmer, but the sound clarity of this DT-770 600 is pretty impressive. Sometimes I prefer the Q701 due to it still being a detail monster but a little more forgiving..but not by much.
 
Can't get over how I really have no complaints about the DT-770 600's sound at all. Usually when I do it has to do more with the music and how it's recorded. Best $117 I ever spent on a headphone for sure!
 
BTW I wonder if the DT-770 600's guts would fit inside the DT-770 Pro 80? Probably would be too much of a pain to do.
 
 

 

[Chris J]

 
Quote:

i did some more testing,  and the 80 ohm does seem louder at the same position of the dial than the 32 ohm.
 
BUT, could this be due to different drivers between the premium and pro versions?
 
or the sound sig since the 80 ohm is bassier it may only appear louder?
 
or is it somehow involving the resistance, where maybe the amp pushes more voltage or something at a higher impedance?
im reaching here i know,  just wondering.  i do find it interesting.
 
however the difference is closer than i first thought.  they could be almost the same, however unless my ears are messed up its not possible that the 32 is louder.  they are either the same or as it sounds to me the 80 ohm is noticably louder at 9 oclock on the dial and even 11 oclock.
 
however the 600 ohm 990 is def not as loud as either at 9ish.  and then by 11 it gets a little screwy because my SS pioneer doesn't have the nuts for it

My guess is probably the output impedance of the SS Pioneer is too high to drive the 32 ohm cans properly. I wouldn' t be surprised if the headphone jack had an output impedance of 70-100 ohms which would make the 80 ohm cans sound louder and make the amp appear to push more voltage into the higher impedance cans.
I guess the different drivers and the bassy 80 ohm cans probably make the 80s sound louder too.
 
As for the 600 ohm cans, makes sense that they are the quietest at 9 o'clock and at 11 o'clock the amp just runs out of enough voltage and you start to hear clipping?

 

[Rawrbington]

Quote:

Am I the only ones that find the Pro models more comfortable than those of the Premium models? I wonder why this is. It's as if the design of the Premium models just does not work with my head. It's as if when I wear them they press on and pull upwards on my ears. Strange huh? I bent the DT-770 600 a bit and now have a much better fit, but it's somewhat loose. The DT-770 Pro 80 is a perfect fit in ever way and the cups are not shallow. I could wear that thing all day.
 

i think the cups are the same aren't they?
i mean the space between the foam driver cover is only dependant on the pad and the pads are the same.  but of course they could very a little bit for every individual pad.  you know what im saying?  or am i off here? 
 
i like the premiums fit better.  just because they are a hair lighter and have a touch less clamp.
 
 
@Chris J the 600's just seem to get out of balance at midhigh volumes.  the bass doesn't keep up and the highs flood in, plus they get loose all round and lose a bit of clarity i think.  maybe a little clipping too.  i just don't usually listen to them loud because of it.  But my Woo WA 3 gets here monday!!!
 
 
anybody have any idea as to what the output impedance is on the wa3?  i know its power band is about 300 ohms.
 

 

[tdockweiler]

Quote:

i think the cups are the same aren't they?
i mean the space between the foam driver cover is only dependant on the pad and the pads are the same.  but of course they could very a little bit for every individual pad.  you know what im saying?  or am i off here? 
 
i like the premiums fit better.  just because they are a hair lighter and have a touch less clamp.
 
 

I think the cups are the same, but maybe the Pro DT-880 isn't as shallow. I doubt it though.
The Pro version seems to just go better with my head due to the way the headband and sides are. I don't know why or how they're any different. It's just strange..It just looks like the premium versions have sides that seem to be at more of an angle. I need to check into this. Maybe that's why the Pro verisons fit better. Maybe I have a head shaped like the Jecklin Float guy?

 
I must be the only person in the world who can't use the Premium versions comfortably.
 
BTW I think the KRKs vs some of the Beyer Dynamic headphones would make for a nice comparison. I might do that if I get the DT-880 Pro. Listening to my KNS-6400 now and it's not like a huge step down in sound from the DT-770 600. Soundstage is actually  just as good.

 

[Armaegis]

Quote:

Hey there, back again.
Please understand, I'm not trying to start a war here, I'm just trying to think this thru........so here goes. This has been a very thought provoking discussion!
If you assume that sensitivity of all DT770/880/990 series is the same for all impedances then I agree with your numbers if sensitivity is 96 dB @ 1 Volt.
 

No offence taken. You were right; I must have been smoking some of the good stuff that day; not sure how I got my wires crossed that badly. I was sort of combining two aspects incorrectly in my head (though the fundamentals individually were correct), and even doing the math I had the axes wrong (as a math teacher I'm kinda embarrased I even goofed that). I plotted them as well and got the same results as you.
 
I've gone back and edited out my post with the graph so it doesn't confuse people. You quoted me afterwards, so I'd ask you please delete that too.
 
Just to note though, I'm not too sure where/how you're going about using efficiency and sensitivity separately. Per my understanding, sensitivity refers to the db produced at a given reference point (typically 1mw or sometimes 1V), and it all scales logarithmically from there. Efficiency shouldn't really come up in this context.
 

 
Quote:

My guess is probably the output impedance of the SS Pioneer is too high to drive the 32 ohm cans properly. I wouldn' t be surprised if the headphone jack had an output impedance of 70-100 ohms which would make the 80 ohm cans sound louder and make the amp appear to push more voltage into the higher impedance cans.
I guess the different drivers and the bassy 80 ohm cans probably make the 80s sound louder too.
 
As for the 600 ohm cans, makes sense that they are the quietest at 9 o'clock and at 11 o'clock the amp just runs out of enough voltage and you start to hear clipping?

I was thinking it might be an output impedance thing too. There could also be a power interaction, as power transfer maximizes when the impedances match... although that shouldn't really have much bearing here.
 
It could also be simply due to a difference in frequency response of the various cans (which once again can also vary each with the output impedance of the amp). Particularly in the bass, stronger/weaker response can drastically affect the perception of volume. It's difficult to quantify sound purely by ear due to how perception changes over the range as well as volume. We'd need an SPL meter to measure.
 

 

[tdockweiler]

I've been reading up on this thing about there being two versions of the DT-770 600. One that's bass heavy and another that's bass light.
 
The pair I have isn't quite bass light, not really even close. I am perfectly happy with the amount of bass on it. It does seem to lack some sub-bass a bit. Even compared to my Q701! The mids do seem fuller sounding than the old DT-880 32 ohm I had, but I'll need to compare them again. The treble is perfectly smooth. Overall, this is still the most balanced headphone I've ever heard. Very similar to my K501 in this area.
 
Seems the DT-770 600 is under-appreciated around here and that's too bad.
 
BTW I have the version with the bass ports! I got it from Amazon. It came in a box with 250 ohm printed on it, but with a big label that said it was 600 ohm. The plug also has this on it.
 
My guess is that Beyer screwed up on some pairs or maybe included the wrong pads. Maybe the bass heavy versions are just defects.
 
Are DT-770 Pro 80 pads and DT-770 600 even different? The pads I have are soft and not like the hard pads that MLE got.
 
This graph looks pretty accurate:
 

 
Weird to think the Q701 has more low bass than this pair. Not that I care.
Probably one of my favorite headphones so far. Just so hard to get used to a headphone that's so unforgiving.
 
I like it so much I'm going to buy the DT-880 Pro just to compare it. I hope the cups are not too shallow.

 

[Armaegis]

I'll bet it you look at a waterfall plot the Beyer will have way more energy in the low end compared to the AKG.

 

[Rawrbington]

i think the pads are the same.  at least mine seem to be.
i've also heard that some 770 premiums are bass light.  but my 32 ohms are not bass light.  i dunno, may have to do with amping or something.
heres the 600 and 32 graph: im actually surprised theres that much difference
the 600's look more like what i'd think the 990s look like, and with more mids than my 32's.  i keep watching amazon for another pair to pop up cheap
 

 
i really wish someone would graph hte Pro 80s.  but i've never found one

 

[stv014]

Quote:

i think the pads are the same.  at least mine seem to be.
i've also heard that some 770 premiums are bass light.  but my 32 ohms are not bass light.  i dunno, may have to do with amping or something.
heres the 600 and 32 graph: im actually surprised theres that much difference
the 600's look more like what i'd think the 990s look like, and with more mids than my 32's.  i keep watching amazon for another pair to pop up cheap
 
i really wish someone would graph hte Pro 80s.  but i've never found one

These graphs are not that reliable, I would not put too much faith into them. When I have the opportunity to see graphs of the same headphone at multiple sites, they are often completely different.
 
Here are some graphs for the DT770 Pro (80 and 250 Ohms), but again, take them with a grain of salt:
http://doctorhead.ru/catalogue/?i=1243&p=1&pr=50&order=4&inum=2
http://doctorhead.ru/catalogue/?i=113&p=1&pr=50&order=4&inum=2
These probably underestimate the amount of bass quite a bit. However, the sound pressure levels measured are close to the specs, and seem to suggest that the 96 dB sensitivity is for 1 mW, rather than 1 Vrms.
For comparison, this page also has measurements of the 250 Ohms version:
http://www.geocities.jp/ryumatsuba/dt770pro.html
 

 

[Chris J]

Quote:

These graphs are not that reliable, I would not put too much faith into them. When I have the opportunity to see graphs of the same headphone at multiple sites, they are often completely different.
 
Here are some graphs for the DT770 Pro (80 and 250 Ohms), but again, take them with a grain of salt:
http://doctorhead.ru/catalogue/?i=1243&p=1&pr=50&order=4&inum=2
http://doctorhead.ru/catalogue/?i=113&p=1&pr=50&order=4&inum=2
These probably underestimate the amount of bass quite a bit. However, the sound pressure levels measured are close to the specs, and seem to suggest that the 96 dB sensitivity is for 1 mW, rather than 1 Vrms.
For comparison, this page also has measurements of the 250 Ohms version:
http://www.geocities.jp/ryumatsuba/dt770pro.html
 

Anyone know how to read Russian? Or the Chinese languages?
Surprising how flat the freq. response is, everyone hears lots of bass from them. I gotta trust the owners of these cans, you can't all be wrong!.
So the efficiency numbers (SPL per milliWatt) for the 80 ohm and the 250 ohm versions are almost identical, 1.6 dB difference.
 But the sensitivity numbers (SPL per Volt) differ by 5.5 dB which is approx. what I would expect.
I wonder why don't just rename the 80 ohm can a 120 ohm can and the 250 ohm can a 300 ohm can?   Hmmmmmmmmmmm.
 

 

[Chris J]

Quote:

No offence taken. You were right; I must have been smoking some of the good stuff that day; not sure how I got my wires crossed that badly. I was sort of combining two aspects incorrectly in my head (though the fundamentals individually were correct), and even doing the math I had the axes wrong (as a math teacher I'm kinda embarrased I even goofed that). I plotted them as well and got the same results as you.
 
I've gone back and edited out my post with the graph so it doesn't confuse people. You quoted me afterwards, so I'd ask you please delete that too.
 
Just to note though, I'm not too sure where/how you're going about using efficiency and sensitivity separately. Per my understanding, sensitivity refers to the db produced at a given reference point (typically 1mw or sometimes 1V), and it all scales logarithmically from there. Efficiency shouldn't really come up in this context.
 

 

I was thinking it might be an output impedance thing too. There could also be a power interaction, as power transfer maximizes when the impedances match... although that shouldn't really have much bearing here.
 
It could also be simply due to a difference in frequency response of the various cans (which once again can also vary each with the output impedance of the amp). Particularly in the bass, stronger/weaker response can drastically affect the perception of volume. It's difficult to quantify sound purely by ear due to how perception changes over the range as well as volume. We'd need an SPL meter to measure.
 

Sir,
As per your request, I deleted some of the old stuff.
Smoking some of the good stuff?  Send me some.............for quality control purposes, of course. LOL

 
 
You are right, my use of the terms "sensitivity" and "efficiency" is somewhat confusing. Obviously they are very related and interdependent.
 
Efficiency is pretty straightforward as it is SPL per milliWatt.
Sensitivity gets confusing because it comes from loudspeaker measurement; for example:
90 dB SPL @ 1 Watt (2.83 Volts @ 8 ohms nominal) at 1 meter, whcih is OK because most loudspeakers are 8 ohms nominal.
 
for headphones?
definition of sensitivity is SPL per Volt, or SPL per mW 
for example, expressed as:   106.8 dB/Volt or 106.8 dB @ 1.0 Volt ref. 1 kHz..........problem is there is no "standard" or "nominal" impedance for headphones, the impedance can be anything from 25 ohms to 2000 ohms so hard to reference Voltage when referring to several headphones of differing impedances, so the dB/Volt number has gotta be different for diffferent impedances.
 
definition of efficiency is SPL per Watt (or milliWatt for us headphone guys)   
for example:   97.1 dB/mW    or 97.1 dB @ 1 mW ref. 1 kHz
and is approx. the same number for the various Beyer impedances.
 
The impedance matching thing:
When the impedance is "matched": i.e. output impedance of amp = impedance of headphones and you get "maximum power transfer".
However you really don't want "Maximum Power Transfer" because:
efficiency of the system is terrible: 50 % of output power is lost on the output impedance and only 50% of the output power reaches the headphone.
In addition, damping factor is terrible and equals 1.0 and the amplifier's control over the headphone is poor.
http://en.wikipedia.org/wiki/Damping_factor
 
This is why amplifier output impedance should be much, much lower lower (approaching zero) than the headphone impedance.
High efficiency, better control over the headphone diaphragm.
 
Thoughts?
 

 

[Armaegis]

Quote:

Sir,
As per your request, I deleted some of the old stuff.
Smoking some of the good stuff?  Send me some.............for quality control purposes, of course. LOL

 
 
You are right, my use of the terms "sensitivity" and "efficiency" is somewhat confusing. Obviously they are very related and interdependent.
 
Efficiency is pretty straightforward as it is SPL per milliWatt.
Sensitivity gets confusing because it comes from loudspeaker measurement; for example:
90 dB SPL @ 1 Watt (2.83 Volts @ 8 ohms nominal) at 1 meter, whcih is OK because most loudspeakers are 8 ohms nominal.
 
for headphones?
definition of sensitivity is SPL per Volt, or SPL per mW 
for example, expressed as:   106.8 dB/Volt or 106.8 dB @ 1.0 Volt ref. 1 kHz..........problem is there is no "standard" or "nominal" impedance for headphones, the impedance can be anything from 25 ohms to 2000 ohms so hard to reference Voltage when referring to several headphones of differing impedances, so the dB/Volt number has gotta be different for diffferent impedances.
 
definition of efficiency is SPL per Watt (or milliWatt for us headphone guys)   
for example:   97.1 dB/mW    or 97.1 dB @ 1 mW ref. 1 kHz
and is approx. the same number for the various Beyer impedances.
 
The impedance matching thing:
When the impedance is "matched": i.e. output impedance of amp = impedance of headphones and you get "maximum power transfer".
However you really don't want "Maximum Power Transfer" because:
efficiency of the system is terrible: 50 % of output power is lost on the output impedance and only 50% of the output power reaches the headphone.
In addition, damping factor is terrible and equals 1.0 and the amplifier's control over the headphone is poor.
http://en.wikipedia.org/wiki/Damping_factor
 
This is why amplifier output impedance should be much, much lower lower (approaching zero) than the headphone impedance.
High efficiency, better control over the headphone diaphragm.
 
Thoughts?
 

 

http://en.wikipedia.org/wiki/Loudspeaker#Efficiency_vs._sensitivity
 
Quote:

1. Typical home loudspeakers have sensitivities of about 85 to 95 dB for 1 W @ 1 m—an efficiency of 0.5–4%.
2. Sound reinforcement and public address loudspeakers have sensitivities of perhaps 95 to 102 dB for 1 W @ 1 m—an efficiency of 4–10%.
3. Rock concert, stadium PA, marine hailing, etc. speakers generally have higher sensitivities of 103 to 110 dB for 1 W @ 1 m—an efficiency of 10–20%.

 
When talking about impedance matching for power transfer, I don't think that considers the voltage divider. I believe it's referring purely to the electrical efficiency between amp and driver (or maybe it considers both). I'm sure the actual formulations are far more complex than either of us is aware of.
 
As for damping factor, while I generally agree that higher is better (though it is perhaps possible to overdamp), the Beyers are one of the cases where I find they sound better from a high output impedance amp (such as from my Bottlehead Crack which has an output impedance of 120 ohms).
 
 
 

 

[Rawrbington]

Quote:

These graphs are not that reliable, I would not put too much faith into them. When I have the opportunity to see graphs of the same headphone at multiple sites, they are often completely different.
 
Here are some graphs for the DT770 Pro (80 and 250 Ohms), but again, take them with a grain of salt:
http://doctorhead.ru/catalogue/?i=1243&p=1&pr=50&order=4&inum=2
http://doctorhead.ru/catalogue/?i=113&p=1&pr=50&order=4&inum=2
These probably underestimate the amount of bass quite a bit. However, the sound pressure levels measured are close to the specs, and seem to suggest that the 96 dB sensitivity is for 1 mW, rather than 1 Vrms.
For comparison, this page also has measurements of the 250 Ohms version:
http://www.geocities.jp/ryumatsuba/dt770pro.html
 

WOW.  thos graphs are crazy.  idk how accurate they are either, but perhaps they are just a bit averaged or something.  idk can't think of the right word.  but the 80 ohm version... i would think it would look more lopsided.  anyways its interesting to see the impedance measurments of both the pros.