Focal Clear Review (headphone)

[Rottmannash]

And very beautiful song as well.

 

[nhatlam96]

Needs to be low (< 10 Ohm)

I have trouble understanding the Focal Arche, which is a DAC and AMP combo with an extra feature.
The DAC is an AKM 4490.
The amp has good measurements.
The extra feature is amp output impedance matching for the Focal headphones via modes... but you said it just needs to be lower than 10ohm. That would mean you could get the same sound quality with this setup:
DAC = Sanskrit 10th MK2 (AKM 4490)
AMP = SP200 (good measurements) + 1.3ohm output impedance.
Which makes me wonder why the Focal Arche is so expensive... is there more to it than just having lower than 10 ohm? Is there a difference in sound between 1ohm - 7ohm - 9,9 ohm - 10 ohm?
Is there any truth behind Focal Arche synergy between their components? They say the synergy between the DAC Amp and headphone is important

 

[Degru]

I have trouble understanding the Focal Arche, which is a DAC and AMP combo with an extra feature.
The DAC is an AKM 4490.
The amp has good measurements.
The extra feature is amp output impedance matching for the Focal headphones via modes... but you said it just needs to be lower than 10ohm. That would mean you could get the same sound quality with this setup:
DAC = Sanskrit 10th MK2 (AKM 4490)
AMP = SP200 (good measurements) + 1.3ohm output impedance.
Which makes me wonder why the Focal Arche is so expensive... is there more to it than just having lower than 10 ohm? Is there a difference in sound between 1ohm - 7ohm - 9,9 ohm - 10 ohm?

I thought the Arche had built in EQ profiles for the different models?

 

[nhatlam96]

I thought the Arche had built in EQ profiles for the different models?

The post says impedance matching.

 

[amirm]

But then what is the SPL max of the Clear without bottoming clipping clicking?
At 1kHz and 20 Hz

I could determine this but I really don't want to torture this expensive headphone anymore!

 

[richard12511]

Yes I know it's a

Yes I know it's a self preservation design at high volumes. If it's happening at volumes less than intended then there is an issue. I'm not being a fanboy. There's plenty of others here who can't get their Focals to clip. This "review" is trying to paint them as a bad headphone and that's simply not true and in fact they are top tier.

The review isn't painting them as a bad headphone, though. Just because they weren't recommended doesn't mean they're a bad headphone. Getting a "recommendation" from Amir is not like getting recommendation from other reviewers, who basically "recommend" anything that's not bad. Amir typically only recommends finds to be great, so the lack of recommendation here doesn't mean he thought they were bad. In fact, you can see that there were many positive remarks about the headphone, and he preferred the out of the box response over many other headphones he's reviewed.

 

[dfuller]

I'm fairly impressed by the 94dB SPL distortion (realistically, I don't listen to music anywhere near that loud especially with headphones), which is very low. Now, if they could solve the weird driver misbehavior...

 

[amirm]

The post says impedance matching.

If the headphone amp impedance is high, it will change the frequency response of the headphone. To the extent this corrects an error in the frequency response, then it can be beneficial. Alas, this is a very crude instrument and you are much better off using EQ. Most of the time I think high impedance is sold as a feature this way rather than a bug that it is. After all, even if the frequency response is corrected, you lose power due to high impedance in the amplifier.

 

[nhatlam96]

it will change the frequency response of the headphone

how do I know, what headphone is more sensitive to output impedance than others? Focal Clear has 55ohms, which is quite low, does this has any relation to amp output impedance? Solderdude said everything under 10ohm for the Clear is fine, but I do not know the math behind this

 

[Degru]

The post says impedance matching.

Interesting. Not unreasonable tho.

Mysphere 3.2 for example works best with 60 ohm OI. It too has a very substantial impedance spike at its resonant frequency. Not out of the question for focal drivers to be similar. However a few resistors and any other amplifier would do the same thing

 

[amirm]

how do I know, what headphone is more sensitive to output impedance than others? Focal Clear has 55ohms, which is quite low, does this has any relation to amp output impedance?

No. The key is whether the impedance is constant vs frequency or not. With Clear, it is very variable:

See how it peaks as much as 342 ohm?

In contrast, this is the HE400i:

The highs and lows are within just 1 or 2 ohms. So no issue with HE400i but big issue with Focal Clear.

 

[nhatlam96]

No. The key is whether the impedance is constant vs frequency or not. With Clear, it is very variable:

See how it peaks as much as 342 ohm?
The highs and lows are within just 1 or 2 ohms. So no issue with HE400i but big issue with Focal Clear.

I don't understand the graph
A 1khz tone is being played for a 60ohm headphone (focal clear).
In this graph, the 60hz frequency would be then perceived louder than other frequencies, so I hear more bass or thickness.
What is the cause for this 60hz resonance peak?
What is the relation between the 342 ohm and the 60hz?
What amp has been used here?

 

[JohnYang1997]

I don't understand the graph
A 1khz tone is being played for a 60ohm headphone (focal clear).
In this graph, the 60hz frequency would be then perceived louder than other frequencies, so I hear more bass or thickness.
What is the cause for this 60hz resonance peak?
What is the relation between the 342 ohm and the 60hz?
What amp has been used here?

The coil in dynamic headphone driver causes the peak. This peak happens with majority of dynamic headphones but very prominent here with focals.

With higher output impedance (flat across the frequency assuming) more voltage share will be at the peak frequencies hence the peak frequencies get louder.

 

[JohnYang1997]

And keep in mind. If an amp has low enough output impedance there will be no issue. It's just a nature of some headphones that we can look out for.

 

[amirm]

I don't understand the graph
A 1khz tone is being played for a 60ohm headphone (focal clear).

It is not. A complete suite of frequencies are played and impedance computed for each and plotted.

In this graph, the 60hz frequency would be then perceived louder than other frequencies, so I hear more bass or thickness.

That is not what the graph is for, or is. It is not showing you the frequency response. It is showing you the electrical impedance. If your amp has very low impedance, then the fact that the impedance changes does not change the loudness.

What is the cause for this 60hz resonance peak?

Electrical/acoustic properties of the driver.

What is the relation between the 342 ohm and the 60hz?

The headphone presents a very high "resistance" at that frequency compared to others. The manufacturer single numbers such as 60 ohm is therefore quite wrong.

What amp has been used here?

Topping A90. Any other low impedance amp could have been used to generate similar results.

Bottom line: many headphones have impedances that change with frequency. This is the reason you want a very low output impedance in your amplifier. If you have such, then it won't care that the headphone impedance changes. If on the other hand you have a high impedance headphone amp, then you have to do some math and figure out how the frequency response gets modified beyond what I have shown.

 

[nhatlam96]

Headphones have impedances that change with frequency. The manufacturer single numbers such as 60 ohm is therefore quite wrong.

How do the manufactures determine the headphone impedance then? Is it like the avarage impedance across the frequencies?

If you have a high impedance headphone amp

How can we determine what impedance value would be too high for a specific headphone?

 

[amirm]

How do the manufactures determine the headphone impedance then? Is it like the avarage impedance across the frequencies?

Who knows. Some use averaging. Some just pick one frequency. There is an IEC standard but I don't think anyone is using it in their specs.

This and sensitivity are the most abused specs in headphones and speakers.

How can we determine what impedance value would be too high for a specific headphone?

The general rule is that the output impedance of an amplifier should not be more than 10% of the headphone you are going to drive. That way the impact is very small. Better yet, pick an amplifier with output impedance below 1.5 ohm or so in my measurements and you are golden regardless of what headphone you buy.

 

[Rja4000]

No. Problem has been reported broadly online and by other owners in this thread. Here is the company itself:



And machine translation:

"What you are describing is a known phenomenon but it is not a defect of the helmet.
Let me explain, we made a choice in the design of our high-end helmets. The latter were designed to respect as much as possible the dynamics of the audio signal rather than the compression dynamics which would offer a higher SPL but would respect less the audio signal. In short, we preferred to favor the acoustic quality at the SPL, which allows us to benefit from optimal performance until the heightening occurs (the click heard). So, on some songs, at very low frequencies or at very high volume, you can hear this click. This also exists on hi-fi speakers.
Therefore, swapping in your helmet will not change anything.
The only solution we offer is to listen at a lower volume.
Best regards,
Marine, Focal Community Manager "

Couldn't be more clear, pun intended.

Now, if you think otherwise, contact Focal and ask them if they provide warranty service and deny the statement above. Don't keep posting as a fanboi. We can do without such.

Hi @amirm
(EDITED after clarification from Amirm)

Their explanation doesn't look convincing to me, and I reported it as is, without translation, to avoid translation-induced bias.
That's at least an official acknowledgement of what you found. And a confirmation that such a problem was reported before, for different models, including the incredibly expensive Utopia.

About my question:
Accoustic Compression is a real think, not just a marketing invention.
It would read in measurements as distortion, for sure. And most probably as a change in measured FR with level.
But is there a way to measure it directly ?
To qualify that as a difference in user experience ?
I'm interested in your opinion on this.

 

[RayDunzl]

Depends on the track I'd think. Here's a snippet from one of my future bass songs. Sub-20hz bass hit.

Wow. 60db above the general level.

 

[nhatlam96]

pick an amplifier with output impedance below 1.5 ohm and you are golden. The general rule is that the output impedance of an amplifier should not be more than 10% of the headphone you are going to drive.

Otherwise with a high impedance headphone amp, you have to do some math and figure out how the frequency response gets modified.

How was that 10% rule made? Sorry for being annoying

This and sensitivity are the most abused specs in headphones and speakers.

A good example could be dt880, which has different impedance models, like 250ohm and 600ohm. With a closer look on these headphone models, we can then find out how they determine those headphone ohm values?

With higher output impedance (flat across the frequency assuming) more voltage share will be at the peak frequencies hence the peak frequencies get louder.

Is this related to Voltage = Current * Resistance?

For example: there is high resistance on a specific frequency, which will result in high output voltage for that frequency. Output voltage also determines the output volume level for that frequency.