RAAL requisite audio SR1a Review: HOLY MOLY! Buy this now!

Discussion in 'Headphones' started by purr1n, Jul 12, 2019.

  1. purr1n

    purr1n Desire for betterer is endless.

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    Elex 4.8kHz
    upload_2019-8-3_22-19-7.png

    LCD3 4.8kHz
    upload_2019-8-3_22-21-48.png

    SR1a 4.8kHz
    upload_2019-8-3_22-20-27.png
     
  2. purr1n

    purr1n Desire for betterer is endless.

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    250Hz + 8kHz dual tone burst


    LCD3
    upload_2019-8-3_22-26-21.png


    SR1a
    upload_2019-8-3_22-27-6.png

    HD700
    upload_2019-8-3_22-32-33.png
     
  3. ChaChaRealSmooth

    ChaChaRealSmooth SBAF's Mr. Bean

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  4. Lyander

    Lyander Official SBAF Equitable Empathizer

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    +1, not quite sure how to interpret. Is it whether or not the two frequencies will mess with each other's forms, trying to simulate the actual mess of real music?
     
  5. themystical

    themystical New

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    So I received my Raal Requisite SR1A's earlier this week, delivered personally by Danny the CEO of Raal Requisite, no less! He came to Manchester after attending CANJAM in London and I spent a very interesting evening with him talking about all sorts of things audio. He is clearly a very talented partner to Aleks of Raal and it is obvious that it is the interplay and mingling of ideas that has given us this novel headphone.

    So I guess the question most people have (and the one I had before I got these) is " Is it all hype?". After all on Headfi, every new headphone seems to be portrayed as the second coming? Thank goodness for the more measured attitude on this forum.


    [​IMG]fullsizeoutput_329 by themystical2012, on Flickr

    I
    have only had a couple of hours with the headphone but it is immediately obvious that this is the best headphone I have ever heard and I have owned and heard many of TOTL's including electrostats, dynamic and planar. My headphone of choice over the last couple of decades has been the venerable AKG K1000 and properly amped, none of the modern competition such as the Utopias, HD800's, LCD's, Stax 007's, HE60's etc have the sheer palpability, resolution, speed and impact exceeding it - equal in some respects, yes, but none of these give real people and voices playing real instruments like the K1000's do. The SR1A is the real spiritual successor to the K1000's adding bass and even more palpability, tactility, resolution and impact. In fact I perceive the SR1A to exceed the performance of the K1000's in all respects using the same set up (source, DAC and Amp)

    The design of the headphones is completely non-compromising in a "form follows function" industrial way and I love it for not trying to be bling and artificially beautiful and audio jewellery like!

    [​IMG]fullsizeoutput_32c by themystical2012, on Flickr

    To get the level of performance that I am getting out of these phones, I believe that you have to get the source (DAC) and the amp right. I am an Electrical Engineer by profession and my personal experience has been that whilst measured performance of equipment becomes inaudible at a certain point, the improvement comes through not as purely what you hear but the placement and soundstage, the "concentration" of the sound so that all instruments and even voices have impact and you can "physically" feel the music. The DAC that I am using is a Sabre ES9038Pro DIY with around 132dB SNR. So as not to lose this hard earned SNR in the amp, I use again a DIY Ncore NC500 Class D design by Bruno Putzey (ex Hypex) which produces 500W into 4 Ohms and 350W into 8. The amp has a SNR of 124dB and the majority of the signal including spatial cues etc. is preserved. The low frequencies are all present with due impact - absolutely no need for EQ as some people seem to need.

    So is this the best headphone in the world? Probably! I have not heard the classic Orpheus or the Sony R10's but I cannot imagine these will exceed the palpability and sheer presence of the SR1A's.

    At USD3500 the headphones are quite expensive but I really baulk at having to pay and extra 20-25% in custom duties and VAT here in the UK/EU and fortunately with Danny carrying them into the country by hand, I didn't have to. That is the only way I have been able to afford them. Danny had a second pair of SR1A's with him when he came to deliver mine and I persuaded him not to take these back to the States and that I would ship these to somebody in the UK/EU, hence saving on customs/VAT for the lucky person! Danny is contactable by email
    [email protected] but I do know that he will not be back in the States until sometime next week and that he is currently having problems receiving emails. You can PM me too if you wish.

    [​IMG]fullsizeoutput_324 by themystical2012, on Flickr

    [​IMG]fullsizeoutput_327 by themystical2012, on Flickr
     
    Last edited by a moderator: Aug 4, 2019
  6. allegro

    allegro Friend

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  7. purr1n

    purr1n Desire for betterer is endless.

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    I made minor edits, mostly correcting the font color which was bright white to the SBAF standard off-white shade so our eyes would not be blinded.
     
  8. purr1n

    purr1n Desire for betterer is endless.

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    First of all, I would like to state my credentials: I am a random idiot. I would also like to opine that through my own personal experience, once we start chasing numbers past a certain point, the sound quality actually gets no better or even worse in many cases.

    Secondly: Why would we need 132db and 124db SNR when ambient sound levels in a typical home are going to be 30db SPL at best with typical listening volumes of maybe 75db SPL (maybe 85db peak) for most people? This keeping in mind that the SR1a, as ear monitors, do not seal off the environment, and run into excursion limits at high SPL.
     
    Last edited: Aug 4, 2019
  9. themystical

    themystical New

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    Thank you very much Marv. I have indeed followed and gained from both this site and also the thread on Headfi so I formulated a post that I could share on both threads and the copy/paste did not work as well a I anticipated it to.

    I agree with you up to a point. I have heard equipment with not so good numbers sound really good but have never had equipment with good numbers sound bad. What I was trying to convey is that it is not simply about the sound that one hears - that stops improving after a certain number - but things like positional cues and the focus and physical impact i.e vibrations that you feel etc. keep on improving. I do a lot of DIY and as I improve certain aspects of the design, I can analyse the "improvements" and this is what I see. I guess the subjective elements are very individual and personal and the truth is what each sees. The bottom line for me is that the Ncore NC500's sound excellent with these headphones provided the source is up to the job.
     
  10. drgumbybrain

    drgumbybrain Science Nut

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    Sorry about the stupid question, but have you tried to use Raal completely relaxed in a sofa or bed? Does the headband can hold the headphone weight? I was wondering if those are only usable in vertical position, sitting in a vertical chair.
     
  11. Zhanming057

    Zhanming057 Friend

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    For me, yes, chair only. The Mysphere I can keep using until I'm at a 45 degree incline. I can go maybe 15 degrees back on the SR1a. When I'm in bed, I have to listen the 1266 phi or IEMs.
     
  12. allegro

    allegro Friend

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    Only 15 degrees reclined ... good to know thanks. I often listen with my HD800S in a recliner relaxing at 45 degrees that would be a deal breaker for me unless RAAL addresses that issue.
     
  13. mscott58

    mscott58 Friend

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    Seems like you could DIY that problem - maybe duct tape and/or staple gun?

    [​IMG]
     
  14. Zhanming057

    Zhanming057 Friend

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    You can probably mod them, but the problem is that with a point of anchor behind the ears, you'll need a stabilizing strap that goes on the forehead to counterbalance the drivers. Not sure how you could do this for an open baffle headphone without clamping force on the head which comes with it's it' issues (e.g. some people physically can't fit the Mysphere on their head).

    The cans are very modular, though. I imagine that you can get them to stay on with thicker foam strips in front of the drivers. I no longer have a 3d printer but it would be nice to have one to play with this stuff
     
  15. Vtory

    Vtory Audiophile™

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    Raal claims SR1a's sensitivity as 91db/W (based on adapter in). But I've been feeling it didn't match to my subjective perception well. So, sensitivity quickly taken via Minidsp EARS, Topping DX3 pro, and Vidar.

    Numbers used:
    • Vidar's gain = +25.2 db as shown in Schiit's AP measurements (0.11 Vrms in, 2.005 Vrms out)
    • DX3's 0dbFS output = 2.05 Vrms
    • SR1a adapter box Z at 500hz = 6.5 ohm (from @purr1n 's results)
    Test signal = -34 dbFS 500 hz sine wave = 0.744 Vrms amp out = -10.69 dbW amp out
    (Lower level signal used than IEC-60268-7 as I worried potential damages to ribbons)

    On SR1a end = 78.2 dbZ (unweighted)

    So, SPL sensitivity at 1W was estimated around 88.9 dbZ, a little lower than claimed.

    I don't think Raal overstated. It's rather the nature of this sorta measurement. Results should be interpreted with the following considerations:
    • Very close distance between ribbon and measuring mic (it's quite different from 1m in typical speaker spl measurements). And the inverse-square law for wave radiation.
    • Wing angle (25-ish degree open in my case) also affects ribbon-mic distance.
    • SR1a doesn't sit well on EARS. Ribbon-mic distance possibly closer than I normally place on my (actual) head.
    • Human (cheek) skin acoustics vs EARS' silicon acoustics. Hmm.
    Taken together, 86-ish db per watt seems a more reasonable and practical estimate of sensitivity for real use. That's also more in line with the need of high power amplification.
     
  16. purr1n

    purr1n Desire for betterer is endless.

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    I'm so tempted to grab a used TOTL Crown DSi series Class D amp, just to try with these.
     
  17. Serious

    Serious Inquisitive Frequency Response Plot

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    LOL, so I guess the 85db/mW or 115db/W figure from the 6moons review was just the driver itself. Is the whole system really 45db less efficient than normal headphones? HD800 is 101db/mW or 131db/W (nominally, I haven't tried to see if it can handle 1W without a high pass) from my own measurements and IEMs are only around 10db (maybe 15db) more efficient than that.
    Given the power consumption I'm not too surprised by the distortion measurements. If the 6moons figure is accurate, just the driver needs 40 times as much power as a normal dynamic headphone driver does. The whole system is 31 000 times less power efficient?
     
    Last edited: Aug 14, 2019
  18. Zhanming057

    Zhanming057 Friend

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    At listening volume (90-ish db for me) and my preferred flap location, I do see spikes of up to 40w with around 5-10w output usually, so 85-90 db/w sounds like the right ballpark.

    85 db/mw is only a bit more efficient than the K1000 (83 db/mw). That sounds highly implausible for a driver-only figure. It would be pretty challenging to measure the driver spl on its own, most rigs might just see it as a short and go into protection.
     
  19. Vtory

    Vtory Audiophile™

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    Yeah, horribly inefficient.

    The whole system is like:

    Adapter circuit (Z=6-8 ohm) - transformer - 0.18 ohm cable - 0.02 ohm ribbon (as claimed 85db/mW)

    And this is why "direct-drive" is believed to do miracles by some, myself included. Haha.

    PS. Seeing the current Texas electricity danger, I feel a little guilty in driving this inefficient headphone via also quite inefficient (high bias class AB) power amp. Oh well.
     
  20. skem

    skem Friend

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    Some thoughts: burst responses show SR1A is underdamped at 50Hz. That’s strange given how light it is. I guess that’s the underlying technology. The others are over-damped at 120Hz. I read this as SR1A as less good at ultra low frequency transients you can’t hear anyway, and superior at high frequency transients that matter. ELEX is nonetheless impressive in a well rounded sort of way.

    In the vein of the Crown amps Marv is testing, I recently tried Behringer Europower EP2000. My advice is to stay away from the Behringer. I’d rather listen to a dying cat.
     
    Last edited: Aug 14, 2019

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