Beyerdynamic DT770 Pro 80 ohms occasional distortion!

[Waynester]

Hi everyone

I’m a professional musician, keyboard player and vocalist in various bands in the UK

I’m after a new pair of headphones, currently have the Beyerdynamic DT770 Pro 80 ohms model, I’ve always been underwhelmed by their sound (dunno why) a bit of distortion sometimes, but extremely comfortable to wear and well built…

have I actually bought the wrong ohms model? maybe the 32 ohms would fix the distortion issue?

I do not do any recording or mixing and currently have these headphones plugged straight into my Soundcraft EFX12 Mixing Desk (non powered desk)

my keyboards and vocal mics are then plugged into the desk, I just practise songs along to original tracks I’m learning for my gigs… the tracks are playing from my High Spec Windows PC, straight into my Solid State Logic SSL 2+ Audio Interface, which also goes into my Mixer..

are there a set of headphones you’d recommend that will sound awesome for what I use them for?

I have just tried a pair of Sony MDR-7506 and these do not distort… Very odd

[ef37a]

Hi Wayne and welcome. Oh! I DO wish headphone manufacturers would get their specifications together!

No figure is given for the sensitivity of your Beyers except "Nominal level 96dB".
Is that at 1V input? One mW? They give the maximum input as 100mW.

Sony do give a "sensitivity" but a bare "106 dB" no reference voltage or power level. They do however give a maximum power input of 1 watt, ten time that of the Beyers.

On the basis of those (poorly stated) figures the Sony headphones are significantly more sensitive and can handle much higher levels. They would therefore likely produce less distortion from any given source.

All that said however, Beyer headphones are a well respected 'industry standard' and I would be surprised to find them wanting? Are you sure you are not monitoring at exessively loud. possibly damaging levels? Easy to get into the habit with cans!

Dave.

[Hugh Robjohns]

Much as Dave suggests, my guess is that its actually the headphone amp in the mixer that's running out of steam and distorting. The Sony phones are a lot more sensitive so will go louder with less oomph from the amp.

The EFX12 specs give the headphone output as 300mW with 150 Ohm headphones.

I think the Sony are 64 Ohms impedance compared to the Beyers 80 Ohms, so not chalk and cheese different and unlikely to affect the mixers headphone amp's performance too significantly.

So your three practical options are:

1. Ditch the Beyers and find some new, more sensitive headphones that play nicely with the mixer's headphone amp and deliver the volume you want.

2. Keep the Beyers and use a high quality headphone amp that drives them well to the volume you want, rather than the mixer to power them.

3. Learn to work with lower headphone levels — and although that might sound patronising, it is worth serious thought as it is very easy to listen at much higher levels under headphones than you might realise... with the attendant longterm risks to hearing.

The Beyers are good closed-back headphones and one of the most comfortable...

[Waynester]

Thanks guys!

I’m gonna send the 80ohms DT770 Pro’s back next week! I’ve ordered the 32 ohms and the 250 ohms models…I really do like the build quality of the Beyers and they are the most comfortable headphones over any others by far

I’ll try the 32 on my EFX 12 Mixer, but when I rang Soundcraft today, the technical guy told me the mixer I have is rated at 150ohms?? So they said I should get the 250ohms headphones
Will the mixer be able to drive the 250’s??

As I said the Sony doesn’t distort and they sound okay

I may even keep the 32 ohms Beyers for my iPhone 15 Pro Max and laptop… should be great for those devices ?

Did even think about getting some Audio Technica ATH-M50X’s, dunno what the impedance and ohms are on them?

[Hugh Robjohns]

As I mentioned above, the Soundcraft specs give a power rating for a specific load impedance — in this case, 150 Ohms and 300mW.

The maximum power will vary with load impedance, so manufacturers normally quote the value that gives maximum power.

As I also said, the Sony phones have a lower impedance than the Beyer's, so it is likely that the amp would deliver less power to them than the Beyers... but the Sony's higher sensitivity would compensate for that.

I'm sure the Soundcraft will drive the 250 Ohm version of the Beyers, but whether they'll go loud enough for you without distortion only a physical trial will tell.

[ef37a]

Thanks guys!

I’m gonna send the 80ohms DT770 Pro’s back next week! I’ve ordered the 32 ohms and the 250 ohms models… I’ll try the 32 on my EFX 12 Mixer, but when I rang Soundcraft today, the technical guy told me the mixer I have is rated at 150ohms?? So they said I should get the 250ohms headphones
Will the mixer be able to drive the 250’s??

As I said the Sony doesn’t distort and they sound okay

I may even keep the 32 ohms Beyers for my iPhone 15 Pro Max and laptop… should be great for those devices ?

Did even think about getting some Audio Technica ATH-M50X’s, dunno what the impedance and ohms are on them?

Hmm, I would consider instead on getting a decent headphone amplifier? The cans outputs of many devices, interfaces especially, are often less than stellar in terms of maximum level and the gain needed to boost signals down at -20dBFS and below. An amplifiers solves all those issues and will drive virtually any headphone model on the market. Many have multiple outputs. You can also 'pinch' signals from other sources that otherwise couldn't drive headphones. Invaluable for fault tracing.

The amplifiers built into some mixers and AIs are fairly crude (though that has improved) being intended mainly for "que" purposes and the quality not of the best.

I am sure Hugh and others can suggest a couple of models.

Dave.

[Waynester]

Well… I’ll try the 250’s, if they don’t go loud enough I’ll send em straight back and ditch em

[James Perrett]

It is interesting to look at the output circuit of the EFX12. It looks like it may be a Doug Self design using a pair of NE5532 op amp sections in parallel with 75 ohm output resistors on each section. 300mW into 150 ohms implies an output current of 45mA which is very close to the recommended limit for 2 of these op-amps in parallel. If one of the op-amps happens to have a higher resistance output than normal then you could end up with more distortion than expected.

I would have thought that they would be happier driving higher impedance headphones at a lower current.

[sonics]

It does sound like an impedance mismatch to me. The desk output was designed for higher-impedance headphones. My guess is that that 250-ohm set will reduce the distortion significantly, but may not be loud enough for you. The DTs are not very sensitive headphones IME (250-ohm DT 770 Pro).

The solutions are to use a headphone amp, or choose a more suitable pair of headphones.

[Hugh Robjohns]

Here's the schematic James referred to above, in case anyone is interested. I agree that is is more of a voltage supplier than a current supplier, so may well perform better with higher impedance headphones — not least because there'll be much less signal voltage lost across those 75 Ohm output buffers.

[Dan LB]

How do your 80ohm DT770s sound when driven by the SSL 2+?
You could just run your mixer outputs into the SSLs line inputs and monitor from that.

[Waynester]

So…

I just have my windows PC plugged into the SSL 2+
Then the tracks i listen to go from the SSL to 2 chan els on my desk….
I plug my headphones into the headphone socket on the desk

All my keyboards are connected the desk..
I can then play along to the tracks with my keyboards and vocals

I don’t do any recording or mixing on my PC

[Dan LB]

So…

I just have my windows PC plugged into the SSL 2+
Then the tracks i listen to go from the SSL to 2 chan els on my desk….
I plug my headphones into the headphone socket on the desk

All my keyboards are connected the desk..
I can then play along to the tracks with my keyboards and vocals

I don’t do any recording or mixing on my PC

Perhaps I wasn’t clear….

Leave all of your keyboards and your vocal mic connected to the desk but disconnect the SSL’s outputs from it.

Plug the main outputs of the desk into the line inputs on your SSL 2+.

Plug your headphones into the SSL’s headphone output and use the ‘Monitor Mix’ knob on the SSL to set a balance between playback from your PC and the output of the desk.

Do your cans still distort if you set things up this way?

[mountain lion]

Hi

I thought new iphones didnt have headphone jack???

[Waynester]

They don’t… I have the adapter for it