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RAAL requisite CA-1a Headphone Review

Rate this headphone:

  • 1. Poor (headless panther)

    Votes: 169 82.4%
  • 2. Not terrible (postman panther)

    Votes: 24 11.7%
  • 3. Fine (happy panther)

    Votes: 7 3.4%
  • 4. Great (golfing panther)

    Votes: 5 2.4%

  • Total voters
    205

anphex

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I you think of these headphones as an effect module that turns all kinds of music into Hard Trap, it's probably pretty good!​
 

GaryH

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Unlike linear frequency response errors, hearing non-linear distortion requires skill. Proper testing usually involves listening training and filtering out those who do not have critical listening skills.
The listeners were all employees of Harman International who were trained listeners with normal audiometric hearing. All listeners had successfully achieved level 7 or higher in the Harman How to Listen Training software.

And such distortion may very well be level dependent.
After equalization, all five headphones were measured at four different calibrated levels; 82, 88, 94, & 100 dB SPL.
The relative playback levels of the headphones were adjusted to the same level based on ITU-R 1770.2 level. All of the listening tests were conducted at an average playback level of approximately 80 dB (Bweighted, slow) for both listening test sessions.
An important feature of this test is that the playback level is lower than the level which was used in the recordings. The 90 dB recording level would have been uncomfortable and possibly unsafe for the listening subjects. Absolute ecological validity is thus not achievable in this case. If anything, this should result in an increase in the sensitivity of the subjects to audible distortion.
 

04gto

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When I was at CanJam SoCal 2022, I walked right passed these because the RAAL driver technology type produces a sound that I don't think is good in general. I am glad I did not waste my time stopping to listen to this mess. That is the highest distortion I have ever seen on a headphone at any price. Gross.
 
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amirm

amirm

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@GaryH, Harman listener training has nothing whatsoever with detecting non-linear distortions. It is completely about hearing frequency response errors. The term "trained listener" is poorly used in literature. Many papers use them to simply indicate a person works in pro audio world. This is why I use the term "critical listeners" when I talk about ability to hear small non-linear distortions. Training for this is completely different animal and far more difficult than Harman listener training.

As to listening levels, 100 dBSPL is too low for bass response. It is trivial for me to create audible distortion at some listening level in a headphone. "90" dBSPL *flat* response is indeed very loud. Not because of bass but higher frequencies. Real music has energy piled on at very low frequencies so it is not nearly that loud even at 114 dBSPL.

Reference level for recreating live venues calls for 120 dBSPL (actual measurements of multiple concerts at listening position).

These are the reasons I say don't follow that paper. This is my core area of professional expertise. Please listen when I say something and don't quote papers on me. :)
 

GaryH

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@GaryH, Harman listener training has nothing whatsoever with detecting non-linear distortions. It is completely about hearing frequency response errors.
WBF.png
The current Harman listener training software “How to Listen” includes training tasks on spectral distortion as well as spatial, dynamic and various types of nonlinear distortions
@Sean Olive 's blog. :)

As to listening levels, 100 dBSPL is too low for bass response. It is trivial for me to create audible distortion at some listening level in a headphone. "90" dBSPL *flat* response is indeed very loud. Not because of bass but higher frequencies. Real music has energy piled on at very low frequencies so it is not nearly that loud even at 114 dBSPL.

Reference level for recreating live venues calls for 120 dBSPL (actual measurements of multiple concerts at listening position).
 
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Sorry, but no one noticed that Amir tried the ca1a with the old interface created for the sr1a? the correct one is TI 1b
 

TomW

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As to listening levels, 100 dBSPL is too low for bass response. It is trivial for me to create audible distortion at some listening level in a headphone. "90" dBSPL *flat* response is indeed very loud. Not because of bass but higher frequencies. Real music has energy piled on at very low frequencies so it is not nearly that loud even at 114 dBSPL.

What does this mean for real world headphone listening?

I think you have a RME ADI 2 DAC FS and a HD650. I'd be glad if you could post your actual listening level for this combo.
All DSP deactivated, auto ref level "on". With a recent popular pop music album from a CD. Something that's easily available so I can replicate the listening test.

This would help me a lot to better understand the measurements. :)
 

deafenears

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Sorry, but no one noticed that Amir tried the ca1a with the old interface created for the sr1a? the correct one is TI 1b
The TI-1a was created for the CA-1a, not SR-1a. It does include barrels for baffle compensation so can be used with the SR-1a. I have the same one. The TI-1b is the same internals but in a polycarbonate or plastic housing.
 

deafenears

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Yes:


TI is a successor to RI (the resistor interface) and we won't be making those any more.
TI-1a is in a metal box (available now), TI-1b is in a molded box (available in 4 weeks). There is just a limited run of metal box TI's and we won't be making those any more.
I think that for a short period of time, they will overlap until all TI-1a metal boxes are sold out.


The difference between the TI-1a and TI-1b is the housing. The TI-1a is housed in a metal box, very similar to our original resistor Ribbon/Amp Interface. The TI-1b is electrically identical to the TI-1a (same circuit and components) but housed in a moulded box that echos CA-1a shell material.
 

srkbear

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The Dan Clark Stealth and Expanse are well reviewed here.
They are. And in the majority of reviews of their competitors, in terms of price point anyway, they are often trounced for deviating so far from the Harman Curve, but get glowing reports on listening tests, once EQ is applied (like here).

Which leads me to some headphone performance qualifiers that I’m either misunderstanding or that aren’t captured with measurements. I’ve listened to a lot of headphones, and I’m also fully indoctrinated into cognitive bias issues. But clearly, given that the top two favorite cans recommended highly on here (the two you mentioned) have $4,000 price tags, it’s not just me who appreciates the performance differences between the Stealth and some sub $200 Grados that also hug the Harman Curve nicely.

I’m completely convinced of the value of measurements when it comes to DACs and amplifiers, cables and similar gear that lack moving parts, as it were. But I’m just not getting what we’re learning from headphone measurements (and reviews) other than their tonality compliance.

I’m guessing this is just a limitation of the degree to which headphones can be objectively assessed (something I believe Amir has oft warned us about), but how do we account for the non-tonal attributes such as detail retrieval, speed, accuracy, soundstage, build quality, comfort, design, and all other similar factors that we all know define a sublime listening experience from an extraordinarily fine set of cans?

Surely once tonal variations are corrected, there has to be some qualifiers that can be standardized to offer us more comprehensive assessments as we weigh our purchase decisions?
 

JJB70

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Given what you can get for a couple of hundred dollars the only debate about any headphones costing this much should be about how spectacularly good they are, the luxurious build and packaging, the premium materials, stellar support etc. Unfortunately that's not how audio works and I suspect to many these will be lauded because if they're that expensive they must be good.
 

solderdude

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well, the treble curve has a strange trend, as if the SR1's compensation filters were used

Those 'open baffle' correction filters are RCA/XLR cables/plugs that come separate and have to be used before any amp that is being used.
They aren't included in the transformer boxes.

This is what the baffle compensation does (needed for the SR1A)
Schermafdruk van 2022-10-17 08-04-25.png


This is not included with the CA-1A nor should it be used.
Pretty sure these weren't used in the measurements.

I suspect that the plots have been created separately and were referenced at 400Hz. The sensitivity is determined with the closed pads and that efficiency will be different with the open pads (about 5dB lower).

When you were to overlay the plots at say... 3kHz it would become obvious that the open pads 'leak' about 5dB in frequencies below 1.5kHz.
One would get similar results when measuring a closed headphone and lifting the pads a couple of mm a bit like this:
seal-cb1.png


So yes, you are kind of correct but it is not because a filter was used but because it was not used.
 
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Turcoda

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Measurements may be bad, and I've definitely never heard these so I can't comment much except to say that I have a similar chinese knockoff that I greatly love. I have the GL1200s because I was too poor to afford the SR1as at the time. I have heard the SR1a, but actually greatly prefer the GL1200 due to comfort and the fact that the driver sits parallel to the ear. I just absolutely love ribbon-type sound and almost wanted to buy these ca1a now. I've tried some electrostatic headphones and other high end ones and this GL1200 is the only one I ever truly enjoyed. It was this Zeos video that originally sold me on it:
Mind you Zeos did it all wrong and used the crappy interface box that came with it, which happens to be pure garbage. Not saying you should buy ribbon headphones, but they do offer something unique. I've never heard so much detail from any headphone before.
 
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