[Aleksandar R.]

The point, which seems to escape you, is this: We as consumers are attempting to get the most out of a vendor's product. The vendor is making statements about certain potentially fruitful directions to get the product to perform well, which are patently false. A few of us are injecting some truth into the conversation.

Those truths are:
1. Properly implemented, Class-D amplifiers can produce TOTL sound quality.
2. Class-D amplifiers have ridiculously low output impedance, which MAY allow them to drive ribbon transducers directly.
3. Properly implemented, SMPS can outperform LMPS on the dimensions of noise, speed, high current capability, heat production, weight and cost.

1. Fine. But I'll be the judge of that when it comes to putting out MY product on the market. So, it may not be true to me, as it isn't for many people.
2. So what? I designed my headphone ribbons not to depend on damping factor. Actually, they are better to be driven with a current source (infinite output impedance), but that's not practical as you surely know that designing a CS power amp is fighting oscillation above 10k.
Besides, if you have 0 Ohms on one and 0.017 Ohms on the other end of a cable, the dominant resistance in that circuit will be the the cable resistance...which is between 0.2 and 0.5 ohms. Now go and see what is the usual inductance for a 3 meter cable and you tell me if will roll-off the highs when it's terminated with 0.2 Ohms. Even if you design a cable that has low enough inductance (that is possible, I did so), the cable will have 10-50 times more resistance than the ribbon, which throws out your damping factor out of the window.
3. I see that you have chosen your words very carefully. What about the output impedance that you conveniently forgot? What is it at 40 Hz with your petty 4700uF?

Anyhow, as I've already said, IF it's going to be Class D, it will be battery powered, so that ends our discussion here no matter who's right or wrong.
I just can not fathom what made you calling me a dumb liar here? if you are so sure in your knowledge and expertise, please make a product and put it out on the market and then we'll see how right you are, instead of anonymously hiding behind avatars delivering unquestionable truth on the internet.

 

[Aleksandar R.]

Received my new Raal Requisite SR1a headphones yesterday, Friday. Still listening to get a handle on these ribbon headphones - expect to post some initial impressions later - However, with my not -so -'golden ears', feel like would be going out on a limb to give initial impressions with sufficient confidence. Had them for only a day.

SR1A POWER REQUIREMENTS:
Driving them with Hypex Ncore 400 wpc 2-channel amp. I tend to listen at low-to-moderate volumes. I roughly measured the amplifier's power output to the 6 ohm load presented by the SR1a interface box with the headphones connected. I played a piano recording and set the volume level to where I felt that listening started to become uncomfortable. Remarkably, average loudness only required well under 1/4 watt per channel, and also, surprisingly, piano fortissimos demanded under 1 watt - the peaks didn't exceed two watts per channel -as far as I could tell.
Yes, my measurement was crude, because one might expect the highest loudness peaks to take far more power than only 2 watts -- just reporting what I saw.
Perhaps headphone power measurement was roughly verified by a 120 VAC power wattmeter. Wattmeter indicated that 2-ch amp's idle power consumption was 22 watts (with no input signal) -- but amp's AC power input evidently never exceed 23 watts during this piano music test -- according to the AC-power watt meter, anyway.

APPLYING EQ:
So far, I've found that the reported SR1a's excessive resolution for poor quality recordings can be remedied by adding EQ in the playback chain (see graph below).
For poor recordings I applied EQ using Redscape in the playback mix.

Here's a picture, .jpg, of a preliminary, very subject to change, EQ graph giving what I felt allowed euphonic "polite" = subjectively 'forgiving' playback for poor recordings, IMO, YMMV.

At the risk of being flamed, my preliminary impression is, stated hyperbolically, that this EQ in a way, kinda turns the SR1a into an Ether 2 on steroids. --- Why 'steroids'? -- because IMO, so far, the SR1a, even severely toned down by applying EQ, still offers exceptional resolution while sounding euphonic -again, of course YMMV.
Realize that I'm going out on a limb here - but hopefully, will stimulate some helpful conversion(s).

Said enough in this post for now.

I like the EQ trick you did!

 

[Bill13]

That really means nothing.
People with even more impressive credentials have been proven wrong & I have never seen a Class D amp sound better to a equivalent Class A amp in terms of sound quality.

If those $500 NCore amps on eBay were so hot, there would be thousands of people praising them & dumping their Audio Note, Dartzeel, Pass Labs etc... but that hasn't happened.

Yes, it's a subjective subject alright, but in my experience my Hypex N-core sounds at least as good, or better than, anything I've ever heard - including many high-end amps: class A, A-B, and tubes - and that's with my speaker using Raal ribbon tweeters.

Regarding the power required by the Raal SR1A: if there's a belief that even a high-end SMPS runs out steam at low frequencies, one can always chose to overkill = like, get a 2X500wpc Hypex N-core which is capable of order(s) of magnitude times the power ever needed at sane loudness levels - see Hypex amp spec sheets for continuous power Vs freq..
At insane loudness your ears will distort way, way before the 2x500wpc amp will, assuming your hearing, and/or SR1A, isn't seriously damaged first. Anyway, the way I see it, 20 Hz area sub-bass power is not so much a concern with the SR1A.

If those $500 NCore amps on ebay were so hot, there would be thousands of people praising them & dumping their Audio Note, Dartzeel, Pass Labs etc... but that hasn't happened.

It's all a matter of perspective. Is there justification in a $1,200 smartphone or a $100,000 sports car?

The point, which seems to escape you, is this: We as consumers are attempting to get the most out of a vendor's product. The vendor is making statements about certain potentially fruitful directions to get the product to perform well, which are patently false. A few of us are injecting some truth into the conversation.

Those truths are:
1. Properly implemented, Class-D amplifiers can produce TOTL sound quality.
2. Class-D amplifiers have ridiculously low output impedance, which MAY allow them to drive ribbon transducers directly.
3. Properly implemented, SMPS can outperform LMPS on the dimensions of noise, speed, high current capability, heat production, weight and cost.

Class D and SMPS tech still get a bum rap.
As an engineer, I see no inherent reason why SMPS can't provide good continuous power at low frequencies. All a question of proper design/engineering.
Amazed at the amount of subjectivism, and extreme, strongly-held opinions in our audio hobby. $2000+ cables, astronomically-priced interconnects, LP's claimed to sound better than the very best digital recordings, $5000+ phono cartridges(!).
Yes, it's perspective: example: I can appreciate the appeal of a shinny new Ferrari or Lamborghini. Like cars, people want, and only tend to trust reputable brand-name products.

People like me often don't trust eBay - can't view or audition stuff. I tried to buy a Hypex Ncore NC502MP-based 2X500wpc amp currently offered on eBay for $825 (possibly a very good deal IMO) but received no reply to my inquiry. It's like the eBay seller couldn't care less about the customer. Besides, there's a lot of DIY stuff offered that scares most people away.

They are always overrated for the actual power they can supply.

Always? I doubt this all-inclusive statement, to say the least.

BTW, arguably, the Hypex Ncore tech is similar to, but is not actually, class D (according to Bruno Putzeys, Hypex designer).

 

[Zhanming057]

Yes, it's a subjective subject alright, but in my experience my Hypex N-core sounds at least as good, or better than, anything I've ever heard - including many high-end amps: class A, A-B, and tubes - and that's with my speaker using Raal ribbon tweeters.

Regarding the power required by the Raal SR1A: if there's a belief that even a high-end SMPS runs out steam at low frequencies, one can always chose to overkill = like, get a 2X500wpc Hypex N-core which is capable of order(s) of magnitude times the power ever needed at sane loudness levels - see Hypex amp spec sheets for continuous power Vs freq..
At insane loudness your ears will distort way, way before the 2x500wpc amp will, assuming your hearing, and/or SR1A, isn't seriously damaged first. Anyway, the way I see it, 20 Hz area sub-bass power is not so much a concern with the SR1A.






Class D and SMPS tech still get a bum rap.
As an engineer, I see no inherent reason why SMPS can't provide good continuous power at low frequencies. All a question of proper design/engineering.
Amazed at the amount of subjectivism, and extreme, strongly-held opinions in our audio hobby. $2000+ cables, astronomically-priced interconnects, LP's claimed to sound better than the very best digital recordings, $5000+ phono cartridges(!).
Yes, it's perspective: example: I can appreciate the appeal of a shinny new Ferrari or Lamborghini. Like cars, people want, and only tend to trust reputable brand-name products.

People like me often don't trust eBay - can't view or audition stuff. I tried to buy a Hypex Ncore NC502MP-based 2X500wpc amp currently offered on eBay for $825 (possibly a very good deal IMO) but received no reply to my inquiry. It's like the eBay seller couldn't care less about the customer. Besides, there's a lot of DIY stuff offered that scares most people away.



Always? I doubt this all-inclusive statement, to say the least.

BTW, arguably, the Hypex Ncore tech is similar to, but is not actually, class D (according to Bruno Putzeys, Hypex designer).

I agree with some things and disagree with others. I don't have as much EE background as you or Alex but the feedback from people that I trust such as Rob Watts, Masuda or Fang Bian, who actually build excellent speaker and headphone amps, are fairly in agreement about the advantages of LPS over SMPS. Benchmark is very upfront about the design trade-offs as well, we had this conversation at Canjam about the HPA4 just a few days ago.

If you've found what's good for you - great - but most people here have had at least some experience with class D systems, and we nonetheless choose to run class A or AB amps. Many modern hybrids use a small class A and a class D boost stage, which to me is an interesting idea with a lot of potential upsides. Extensive EQ'ing of class D systems is an option (e.g. Esoteric) but involves a lot of time and R&D costs.

Either way, could we leave this conversation behind and stick to the SR1A? I appreciate the EQ profile you built - I'll give it a spin once I get back to my home setup.

 

[Aleksandar R.]

Always? I doubt this all-inclusive statement, to say the least.

BTW, arguably, the Hypex Ncore tech is similar to, but is not actually, class D (according to Bruno Putzeys, Hypex designer).

True, it is very generalized statement, but I'll explain what I meant.
Hypex 2x500W Ncore is rated 1/5th continuous power. Supply is 1.2kW, but if it had to put out continuous 2x500W, the supply will be dissipating 100+ Watts. there is no way that you can wick away 100W of heat off that board from supply only, then another 100W from the amps
It probably holds it for 100ms or something like that, then it starts to throttle.
Noise will rise with power demand, but LPS wouldn't do that. You are free to design your crest factor freely, which might be very useful when wanting good bass slam.

I will try Ncore soon enough to see what's it all about!

 

[Aleksandar R.]

Everyone,
I'm sorry that I brought up the SMPS vs LPS subject up.
I didn't expect it to end up with a fight, but sometimes I can't contain myself.

Venture Guy, when reading again what I wrote, I think I crossed the line. I apologize if I offended you in any way with my last reply.
Throughout my career I have certainly learned to appreciate other people's expertise and I have to tell you, I appreciate your point of view as equally as my own. You must be right about most things, that's a fact. It can't be any other way after 40 years of dealing with something, so I'm not trying to diminish that.
If we could agree that sometimes us, more-listeners-than-engineers also have a valid experience and that some things didn't fully pass the listening tests, I would be the happiest guy at this forum!

Cheers,

Alex

 

[Hi-Fi-Apricity]

I have a question for the folks here that own one of these beats. How does its midrange compare to something like the 007? I saw someone mention that the texture of the midrange was slightly soft, is that in a STAX sorta way or in a different way? That's my biggest worry is that the midrange has an upward slant like the 009 where the lower mids are 5db over the lower mid-range causing the sound to lack body and sound "ethereal". I don't like overly thick mids like that of the HD6X0 series. I own an 007A and I'm looking for a headphone with a similar midrange but a bit more bite and "fun" factor to the sound. Thankyou!

 

[Zhanming057]

@HoloSpice @Hi-Fi-Apricity

The texture isn't soft - it's just revealing enough that even slightly subpar recordings are exposed. The 009 does have the problem you described re: body of the midrange.

The SR1A's midrange might sound lean, but this mostly comes from the fast response speed and not from any FR differences between the lower and upper mids. The midrange response is flat as a pancake - nothing gets emphasized if it's not emphasized in the recordings. Whether that's "fun" is largely dependent on your tastes - but there's definitely a crispness to vocals that I appreciate.

 

[Hi-Fi-Apricity]

@HoloSpice @Hi-Fi-Apricity

The texture isn't soft - it's just revealing enough that even slightly subpar recordings are exposed. The 009 does have the problem you described re: body of the midrange.

The SR1A's midrange might sound lean, but this mostly comes from the fast response speed and not from any FR differences between the lower and upper mids. The midrange response is flat as a pancake - nothing gets emphasized if it's not emphasized in the recordings. Whether that's "fun" is largely dependent on your tastes - but there's definitely a crispness to vocals that I appreciate.

Very insightful, thankyou! I can't wait to purchase a pair here just gotta figure out how I'm going to fit a nice speaker amp into my desk here heh

 

[Articnoise]

I agree with some things and disagree with others. I don't have as much EE background as you or Alex but the feedback from people that I trust such as Rob Watts, Masuda or Fang Bian, who actually build excellent speaker and headphone amps, are fairly in agreement about the advantages of LPS over SMPS. Benchmark is very upfront about the design trade-offs as well, we had this conversation at Canjam about the HPA4 just a few days ago.

If you've found what's good for you - great - but most people here have had at least some experience with class D systems, and we nonetheless choose to run class A or AB amps. Many modern hybrids use a small class A and a class D boost stage, which to me is an interesting idea with a lot of potential upsides. Extensive EQ'ing of class D systems is an option (e.g. Esoteric) but involves a lot of time and R&D costs.

Either way, could we leave this conversation behind and stick to the SR1A? I appreciate the EQ profile you built - I'll give it a spin once I get back to my home setup.

Class D and switching mode power supply (SMPS) are not the same thing. Many amps that are class D (or equivalent) also have a switching mode power supply, but not all. Rob Watts for example use switching mode power supplies but not class D in his gear.

 

[Bill13]

If you've found what's good for you - great - but most people here have had at least some experience with class D systems, and we nonetheless choose to run class A or AB amps.

For those that found most, if not all, class D amps to be lacking, it's interesting that Hypex Ncore tech is not actually class D -- according to Bruno Putzeys, Hypex designer.
Yes, audiophiles tend to have different tastes in amps. -- agree that I've found what works for me -- but still looking for the latest and greatest in audio - especially new TOTL headphone candidates - these days. For me, it's The quest - chase those windmills like Don Quixote in the Man of La Mancha.

 

[Thenewguy007]

Yes, it's a subjective subject alright, but in my experience my Hypex N-core sounds at least as good, or better than, anything I've ever heard - including many high-end amps: class A, A-B, and tubes - and that's with my speaker using Raal ribbon tweeters

I really wish this to be true, but looking at the tech, it's been out for nearly 10+ years & only has a few scattered reviews that don't really match that enthusiasm. If I could buy that $800 amp off eBay & it would match a $6,000 Pass Labs Class A amp, I would jump on it in an instant.
There was a thread on Hypex N-Core audiocircle that was very active, but stopped talking about it since 2012 & I never seen any of the bigger reviewers/sites to make a in-depth review of it.

You got to remember a few years back, people on head-fi were saying the cheap ODAC & O2 combo measured perfectly & would be better than any $10,000 amplifier or DAC combo. That turned out to be complete B.S. So skepticism should be warranted.

 

[Bill13]

I understand that a few Head-Fi members have taken delivery of their new Raal SR1A headphones - but haven't seen initial impressions from them yet. If they are like me, there could be a hesitation to post; I guess it's because this headphone seems so very different compared to any other headphone?

Anyway, although only have a short time available to write this, here goes:

Overall, IMO, YMMV, feel that the SR1A has the most realistic sound I've ever heard; and perhaps even the best imaging. You may take this with a grain of salt, because I don't claim to have 'golden ears' and some comparative headphone impressions are from memory = tentative findings based on owning Stax, Utopia, HD-800, and brief auditions of new Stax 009s Abyss phi, VOCE, Ether 2, and other TOTL candidates.

I previously thought that my HD-800 presented the biggest/deepest soundstage, but SR1A beats it. More of that 'out-of-your-head experience.
After fiddling around awhile with headphone fit, I now believe wearing-comfort is good, & can wear for hours - YMMV.

As in other posts, the SR1A doesn't have the powerful sub-bass of the Abyss phi - but SR1A perhaps makes up for it with its superior bass definition - YMMV.

See below my new so-called 'gen purpose' Redscape EQ that I current use for vast majority of my music files -- for both good and bad audio recordings -- again IMO & YMMV.

When listening to some piano recordings my impression without EQ was that my SR1A was too bright in the trebles (I have a Steinway model B (BTW, only a 'very limited talent' amateur player) to compare in the upper register). I feel that EQ fixed my excessively-bright treble problem, but of course, I'm still doing trial & error experimentation (currently using EQ graph below)

With this EQ now in the playback mix, the Raal SR1A is my go to headphone for just about everything - except maybe home theater action 'boom-boom' movies with heavy sub--bass explosions and canon fire, etc (my EQ'd Audeze LCD-X gives a good head-shaking involvement for that kind of boom-boom stuff) .

Enough for now - gotta run.

 

[Aleksandar R.]

Bill 13,

And you're now encountering the problem I've had during development...
Actually, other people recordings are not a good reference. They may have recorded a piano with a couple of mikes, one for body and one above the strings and mixed it up in a way that you wouldn't.
I got around that by buying a Sony PCM-D100 recorder when it came out and made my own, unprocessed, raw recordings. D-100's mikes are not great, but the tone balance is flat.
If you can get a good recorder and record your piano from where you listen when you play, then you could work out the EQ that makes it true-to-life. Or not at all. I'm not saying that SR1a is ideal, though, but I worked-out the response to be like that for me.
Anyhow, for EQ-ing aside from what you did in bass below 60Hz, try sinking the octave between 5 and 10k for about 4-5 dB. Make it a fairly square-looking hole. Don't touch the midrange and listen for a while to see how that works for you, please.

 

[Hi-Fi-Apricity]

Bill 13,

And you're now encountering the problem I've had during development...
Actually, other people recordings are not a good reference. They may have recorded a piano with a couple of mikes, one for body and one above the strings and mixed it up in a way that you wouldn't.
I got around that by buying a Sony PCM-D100 recorder when it came out and made my own, unprocessed, raw recordings. D-100's mikes are not great, but the tone balance is flat.
If you can get a good recorder and record your piano from where you listen when you play, then you could work out the EQ that makes it true-to-life. Or not at all. I'm not saying that SR1a is ideal, though, but I worked-out the response to be like that for me.
Anyhow, for EQ-ing aside from what you did in bass below 60Hz, try sinking the octave between 5 and 10k for about 4-5 dB. Make it a fairly square-looking hole. Don't touch the midrange and listen for a while to see how that works for you, please.

Are there any measurements of the SR1A or are those under folds?