The Official Beyerdynamic T1 Impressions and Discussion Thread
Jun 21, 2015 at 11:53 AM
Hi! Thanks for the info.
I have found impedance plots against freq for T1 but was curious how I can see the efficiency of T1. Is there an efficiency-frequency plot somewhere? Or is it because of the Ohm's Law justification?
Thanks!

Yes, the Ohm's law justification is fine. Add the frequency response plot (FR), and that's it.
http://www.innerfidelity.com/images/BeyerdynamicT1SN3964.pdf
As you can see, the headphone sounds similarly loud at 100Hz and 1000Hz.

"To perform this test (FR) we drive the headphones with a series of 200 tones at the same voltage and of ever increasing frequency. We then measure the output at each frequency through the ears of the highly-specialized (and pricey!) Head Acoustics microphone."

Mix the two plots (impedance and FR) + the Ohm's law justification and problem solved.

You can think the headphone as totally flat for the sake of simplicity. Then:

1 Vrms @ 100 Hz sounds just as loud as 1 Vrms @ 1000 Hz
But it's a 1300 Ohm load at 100 Hz and 600 Ohm load at 1000 Hz

Ohm's law -----> The headphone needs less power at 100 Hz
(ie, it's more efficient at 100 Hz)

Jun 21, 2015 at 1:04 PM

There's a common misconception here.

Beyerdynamic T1 impedance raises in the mid-bass and there's where the driver is more efficient, so you don't need more power when the impedance is 1300 Ohm.
In fact, it's the other way around, that's the part of the spectrum where you need less power.

1 Vrms into 600 ohm load, drains more current than 1 Vrms into 1300 ohm load, and that's why you need more power to hold 1 Vrms across a 600 Ohm load, and less power to achieve the same with a 1300 ohm load.

So, it's not true that you need a powerful amplifier to bring the bass on the T1.

What's true is that some powerful amplifiers aren't flat.

Not saying that Fiio E17 is the last word in ampification for the T1, don't get me wrong, just trying to clarify some concepts.

Yes, the Ohm's law justification is fine. Add the frequency response plot (FR), and that's it.
http://www.innerfidelity.com/images/BeyerdynamicT1SN3964.pdf
As you can see, the headphone sounds similarly loud at 100Hz and 1000Hz.

"To perform this test (FR) we drive the headphones with a series of 200 tones at the same voltage and of ever increasing frequency. We then measure the output at each frequency through the ears of the highly-specialized (and pricey!) Head Acoustics microphone."

Mix the two plots (impedance and FR) + the Ohm's law justification and problem solved.

You can think the headphone as totally flat for the sake of simplicity. Then:

1 Vrms @ 100 Hz sounds just as loud as 1 Vrms @ 1000 Hz
But it's a 1300 Ohm load at 100 Hz and 600 Ohm load at 1000 Hz

Ohm's law -----> The headphone needs less power at 100 Hz
(ie, it's more efficient at 100 Hz)

Help me here:
I'm one of those who concerns about driving my t1. I get your point, but the problem is that amps has a maximum output voltage. When the impedance of T1 goes up to 1300 ohms, it demands most of its needed power in the form of voltage. The main question is that can amp deliver that much voltage?
Currently, I'm using Vali with my T1 as a startup gear to get used to T1's sound signature. My amp can deliver 115mw at 600 ohms. If we assume that Vali can deliver 50mw at 1300ohms, Vali should deliver around 8 volts. My question from Schiit tech guy was that, can Vali deliver that much voltage? What is the maximum output voltage of Vali at 1300 ohms.

Why do I feel like I've see this picture before?

Maybe it's because all of them are T1

Hi! Thanks for the info.
I have found impedance plots against freq for T1 but was curious how I can see the efficiency of T1. Is there an efficiency-frequency plot somewhere? Or is it because of the Ohm's Law justification?
Thanks!

Hey, I think someone has success with a butter knife earlier in the thread. Check it out! Cheers

Thanks,
Unfortunately, I couldn't find it. I've taken a look at here too

Jun 21, 2015 at 2:47 PM
Help me here:
I'm one of those who concerns about driving my t1. I get your point, but the problem is that amps has a maximum output voltage. When the impedance of T1 goes up to 1300 ohms, it demands most of its needed power in the form of voltage. The main question is that can amp deliver that much voltage?
Currently, I'm using Vali with my T1 as a startup gear to get used to T1's sound signature. My amp can deliver 115mw at 600 ohms. If we assume that Vali can deliver 50mw at 1300ohms, Vali should deliver around 8 volts. My question from Schiit tech guy was that, can Vali deliver that much voltage? What is the maximum output voltage of Vali at 1300 ohms.

Is important to understand that the T1 needs the same voltage at 100 Hz and 1000 Hz. It doesn't need more voltage at 100 Hz.

The Vali is capable of:
5.24 Vrms into 50 Ohm load
8.12 Vrms into 300 Ohm load
8.30 Vrms into 600 Ohm load

You can see how the amp can produce more voltage as the impedance of the load raises.
So it's pretty safe to say that the Vali is able to produce at least 8 Vrms into 1300 Ohm load.

That's enough to drive the T1 over 114 dB SPL

For normal (even quite loud) listening levels, you're done with 4 Vrms.

--------------------------------

Here's another example: (Fiio E10)

16 ohms  =  1.5 Vrms
32 ohms  =  2.1 Vrms
80 ohms  =  2.5 Vrms
300 ohms =  2.52 Vrms
600 ohms =  2.6 Vrms

Higher the impedance, higher the voltage the amp is able to provide.
Sort of asymptotic behaviour.

Jun 21, 2015 at 8:03 PM

Is important to understand that the T1 needs the same voltage at 100 Hz and 1000 Hz. It doesn't need more voltage at 100 Hz.

The Vali is capable of:
5.24 Vrms into 50 Ohm load
8.12 Vrms into 300 Ohm load
8.30 Vrms into 600 Ohm load

You can see how the amp can produce more voltage as the impedance of the load raises.
So it's pretty safe to say that the Vali is able to produce at least 8 Vrms into 1300 Ohm load.

That's enough to drive the T1 over 114 dB SPL

For normal (even quite loud) listening levels, you're done with 4 Vrms.

--------------------------------

Here's another example: (Fiio E10)

16 ohms  =  1.5 Vrms
32 ohms  =  2.1 Vrms
80 ohms  =  2.5 Vrms
300 ohms =  2.52 Vrms
600 ohms =  2.6 Vrms

Higher the impedance, higher the voltage the amp is able to provide.
Sort of asymptotic behaviour.

This is only true up to a point. Which is the voltage limit the amp can provide. If the amp reach it's max voltage, the power delivered to T1 is only half at it's peak impedance. T1's sweet spot is around 5 to 6Vrms. Anything more than that most probably goes untapped. Anything lower than 4 Vrms, T1 may sound underpowered.

Jun 21, 2015 at 11:30 PM

This is only true up to a point. Which is the voltage limit the amp can provide. If the amp reach it's max voltage, the power delivered to T1 is only half at it's peak impedance.

Me x3: You don't need same power across the spectrum to drive a headphone, you need voltage
(power is very little since T1 is a really high impedance headphone).
It doesn't matter that the power delivered at 1200 Ohm is half the power delivered at 600 Ohm, since the headphne is much more efficient (dB SPL / Power) in the mid-bass. What matters is that the amp must be able to provide the same voltage at 1200 Ohm and at 600 Ohm, which is a pretty simple task since there's little current involved.

T1's sweet spot is around 5 to 6Vrms. Anything more than that most probably goes untapped. Anything lower than 4 Vrms, T1 may sound underpowered.

Me x3: What do you mean by 'T1 may sound underpowered'?

Jun 22, 2015 at 12:21 AM
All this ^^^^^^^^^^^ is exactly why I prefer to just get an amp where there is zero doubt of it's ability to drive a headphone and have plenty of reserve...whether said reserve is ever called upon or not.

Jun 22, 2015 at 12:43 AM
All this ^^^^^^^^^^^ is exactly why I prefer to just get an amp where there is zero doubt of it's ability to drive a headphone and have plenty of reserve...whether said reserve is ever called upon or not.

Haha yeah, it's not that expensive after all!
There are too many of these common myths and misconceptions, repeated again and again at a point they start to sound real !!

Pretty sure if we start saying that reserve power is a bad thing because it degrades sound due to the well known 'whocares' phenomena, there will be people soon trying to find out the best way to deal with the well known 'whocares' phenomena.

We can start now:

Jun 22, 2015 at 12:52 AM

Haha yeah, it's not that expensive after all!
There are too many of these common myths and misconceptions, repeated again and again at a point they start to sound real !!

Pretty sure if we start saying that reserve power is a bad thing because it degrades sound due to the well known 'whocares' phenomena, there will be people soon trying to find out the best way to deal with the well known 'whocares' phenomena.

We can start now:

LOL you person!!!

Jun 22, 2015 at 3:11 AM
id take these over the hd800 due to better build and greater sound impact.

Jun 23, 2015 at 5:04 AM
Jun 23, 2015 at 5:25 AM
Hello!

About a year ago I bought my T1 to play with Bottlehead Crack OTL amp. I wished to build Crack and was in search for a good pair of headphones to match with this OTL.
At that time I had a Schiit Modi/Magni combo and thought Modi would be enough for my system.
So currently I run my T1 with Modi/Crack and it seems that T1 are not used at their full potential.

I think Modi is the reason and want to find a good matchig DAC for my T1. Or maybe Crack is also a reason?

Could you help me to find a good DAC, or DAC/Amp combo for T1 ?

Jun 23, 2015 at 5:37 AM
All this ^^^^^^^^^^^ is exactly why I prefer to just get an amp where there is zero doubt of it's ability to drive a headphone and have plenty of reserve...whether said reserve is ever called upon or not.

Exactly right. That is why I bought a Lyr a long time ago and never looked back. I know I got plenty of power for most anything I need or want.

Jun 23, 2015 at 7:18 AM
Exactly right. That is why I bought a Lyr a long time ago and never looked back. I know I got plenty of power for most anything I need or want.

Heck yeah, that thing is a beast.

Jun 23, 2015 at 7:41 AM
Could you help me to find a good DAC, or DAC/Amp combo for T1 ?

Up front: I've never heard neither the Crack nor the Modi.

A very nice combo for the T1 is Meier Audio Daccord (DAC) + Classic (Amp). Neutral and quite potent, with the added benefit of an analog crossfeed that many see as one of the best implementations available (both the Daccord and the Classic offer that, so you could use that even when getting just the DAC).

My preferred DAC is the Benchmark DAC2, with a Beyerdynamic A2 on high output impedance setting for driving the T1 or the T90.

The ifi iDSD Micro offers a very good DAC plus amp with even a battery for mobile use and includes line-out RCA. At ~500,- its hard to beat.

A DAC that spiked my interest some time ago is the Henry Audio USB DAC. I did not come around to try it out, but it looks promising.

Jun 23, 2015 at 8:13 AM
Hello!

About a year ago I bought my T1 to play with Bottlehead Crack OTL amp. I wished to build Crack and was in search for a good pair of headphones to match with this OTL.
At that time I had a Schiit Modi/Magni combo and thought Modi would be enough for my system.
So currently I run my T1 with Modi/Crack and it seems that T1 are not used at their full potential.

I think Modi is the reason and want to find a good matchig DAC for my T1. Or maybe Crack is also a reason?

Could you help me to find a good DAC, or DAC/Amp combo for T1 ?

The BH Crack is a great amp for the T1, you may need to get some good tubes but even the stock ones were pretty good IMO.  As for the DAC, I'm using a UD-301 or Bifrost and the T1 sounds great with either one, more mellow with the Bifrost, more analytical and dynamic with the UD-301.  Just my impressions so far.