Audient iD24 Headphone Output

[pawKer]

I'm looking to upgrade my Focusrite 2i2 2nd gen and I've narrowed down the search, for now, to mainly the Audient iD24 which seems like a great interface and also got a pretty good review from Julian Krause.

However, there's one thing that kept me from pulling the trigger and that was the higher headphone output impedance (22.30 Ohms vs 11.12 Ohms on the 4i4 4th gen vs 0.10 Ohms on something like the RME Babyface). I've got both low impedance and high impedance headphones but I'm worried about the sound of something like the Audio Technica M50Xs on the iD24.

Does anyone have an interface in the iD series (as they all seem to have similar headphone output stats) and these headphones or something of similar impedance (around 38 Ohms) and would be able to tell me how they sound?

Also, does anyone know what is the headphone output impedance of something like the Apollo Twin X? I couldn't find the stats online and I've not seen them in Julian's list either.

Thanks!

 

[AnalogSteph]

I've got both low impedance and high impedance headphones but I'm worried about the sound of something like the Audio Technica M50Xs on the iD24.

I wouldn't be. According to measurements, the M50X has an impedance response approaching ruler-flat. You could run it from a literal current source and FR deviation would still be a good bit under 1 dB compared to a 0 ohm output, i.e. uncritical. On 22 ohms, the worse of both channels would score 0.33 dB, at the very limit of being detectable at all, or a difference of 0.11 dB to 10 ohms (fuhgettaboutit).

If you're curious about other cans you might have, here's the calculator.

Also, does anyone know what is the headphone output impedance of something like the Apollo Twin X? I couldn't find the stats online and I've not seen them in Julian's list either.

Amir doesn't seem to have measured it at the time, unfortunately.

The level relative to Topping DX3Pro curves seems to have dropped by about 5 dB with a 33 ohm load compared to 300 ohms, which would suggest 31.9 ohms of difference. So I reckon it's 33ish ohms.

 

[DVDdoug]

the higher headphone output impedance (22.30 Ohms vs 11.12 Ohms on the 4i4 4th gen vs 0.10 Ohms

Just make sure that's the output impedance. (I don't know.) Usually the specs give the minimum headphone impedance (recommended minimum load). ...Like a power amplifier might be rated for 4 or 8-Ohms. Sometimes there is a damping factor but they usually don't give the output impedance for a power amp.

Usually the headphone output on an interface is just for monitoring while recording and it may not have a lot of output voltage/power. Almost an afterthought.

 

[pawKer]

I wouldn't be. According to measurements, the M50X has an impedance response approaching ruler-flat. You could run it from a literal current source and FR deviation would still be a good bit under 1 dB compared to a 0 ohm output, i.e. uncritical. On 22 ohms, the worse of both channels would score 0.33 dB, at the very limit of being detectable at all, or a difference of 0.11 dB to 10 ohms (fuhgettaboutit).

If you're curious about other cans you might have, here's the calculator.

I was looking for something like that calculator, this is great thank you! I might go ahead and buy it then

The level relative to Topping DX3Pro curves seems to have dropped by about 5 dB with a 33 ohm load compared to 300 ohms, which would suggest 31.9 ohms of difference. So I reckon it's 33ish ohms.

I had a feeling it might also be high but I guess since they don't publish it officially I've not seen people worry about it online.

Just make sure that's the output impedance. (I don't know.) Usually the specs give the minimum headphone impedance (recommended minimum load). ...Like a power amplifier might be rated for 4 or 8-Ohms. Sometimes there is a damping factor but they usually don't give the output impedance for a power amp.

I got the numbers from Julian Krause's measurements, I'll add the version from his latest video below for reference.

 

[Alchemist_]

What is the minimum headphone impedance for this audio interface?

 

[AnalogSteph]

What is the minimum headphone impedance for this audio interface?

That's not a question that makes much sense to ask like that.

I would have few qualms using it with a 16 ohm dynamic driver IEM with near-flat impedance response and typical sensitivity (say 120 dB / V), given that it seems to have no problems driving 32 ohms to rather decent levels. An impedance-critical multi-driver BA IEM sporting a rollercoaster impedance response on the other hand may make the 22 ohm output impedance rather obvious. AKG had dynamic driver IEMs with a nominal 8 ohms at one point, those are likely to be fine, while I'd rather not even try regular 8 ohm speakers with their drastically lower sensitivity (generally about 40 dB less at 1 m).

So the answer very much depends.

 

[Alchemist_]

That's not a question that makes much sense to ask like that.

I would have few qualms using it with a 16 ohm dynamic driver IEM with near-flat impedance response and typical sensitivity (say 120 dB / V), given that it seems to have no problems driving 32 ohms to rather decent levels. An impedance-critical multi-driver BA IEM sporting a rollercoaster impedance response on the other hand may make the 22 ohm output impedance rather obvious. AKG had dynamic driver IEMs with a nominal 8 ohms at one point, those are likely to be fine, while I'd rather not even try regular 8 ohm speakers with their drastically lower sensitivity (generally about 40 dB less at 1 m).

So the answer very much depends.

for example, this is shure 840A = 40 ohms with a sensitivity of 97 dB. As far as I understand, there shouldn’t be any problems?

 

[AnalogSteph]

According to our @solderdude,

SRH-840A

back to Shure back to measurements home Published: Feb-04-2024 NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wig…

diyaudioheaven.wordpress.com

these don't seem to be particularly impedance-critical, and they're of decent sensitivity. Should work fine.

 

[solderdude]

Virtually not output impedance dependent. (green = 120ohm out, red = 0ohm output)

With 116dB/V it is indeed highly sensitive (34ohm imp). Even an EU phone makes it play very loud so well suited for USB audio interfaces and studio/instrument gear.

I modified and filtered mine. Under these conditions it is still my fav. closed headphones. Very comfy as well. I shortened the cable quite a bit (never need 3m of rather stiff cable)