[manueljenkin]

Hello Heinz and everyone!

Heinz, it's a pleasure to read you here!

Here are my measurements of SR1a distortion, 2nd and 3rd harmonics at 100dB and 90dB.




You can see markers with frequency and distortion in % of 2nd and 3rd harmonic.
Measurements are done in steady-state, after the settlement of the diaphragm.

Sure, it measures quite high, but it's not a big deal audibly and I'll explain why.

This is not unlike what speakers would do at high SPL, but speaker's distortion doesn't rise so monotonically as SR1a's distortion and that is very important for distortion audibility. Speakers "clip" much harder, so to speak, but still way softer than amplifiers.
For example, imagine these numbers in an amplifier. It would be terrible to listen to, only because it would do that too abruptly to stay unnoticed.

The thing here is that I have used a progressive compliance to hang the ribbon. The more excursion the signal demands, the tighter the suspension will get, as there was no other way to control the excessive excursion and achieve high enough SPL. Basically, there is a change in resonant frequency as SPL is increased.

The key to understand what's happening here is to watch the resonant frequency change and remember that below that frequency, the output drops at 12dB/oct slope.
You can see the sharp dip in dist.measurements at about 28Hz at 90dB (the resonant frequency at 90dB) and at 100dB, you will see a less sharp dip (the Q-factor got reduced), showing that the resonant frequency has risen to 41-42Hz. That's what a progressive suspension does.

Above the resonant frequency, the distortion peaks at ~9% at 100dB and ~7.5% at 90dB and that is not bad at all for a completely open design.
Below the resonant frequency, the output drops at 12dB/oct., so it's normal to measure higher distortion % at 20Hz because the output has dropped (because the resonant frequency has risen), but audibly, it doesn't attract much attention to itself, as the total distortion output remains low.

The main objective here was to have the distortion to smoothly increase with SPL and smoothly decrease as we go higher in frequency, as in my experience with speakers, those are the things that make it inobtrusive, if not downright inaudible in bass.

In mid-high range, things are much more demanding and while the same rules about smooth distortion progression apply, the allowable numbers are much, much lower and the graphs reflect that this was the goal.

All in all, what counts here is the distortion above 40Hz, where we have a good output at high SPL, not what happens below the -3 point of the frequency response. The numbers there are very much speaker-like, so they are nothing out of the ordinary. The lack of artifacts that are unrelated to music is very important.

Also, a very important thing about distortion audibility in transducers is a very clean impulse response.
No generated harmonics or any other artifacts should last longer than the signal that caused them. There shouldn't be distortion harmonics that can "ride" on top of ridges in spectral decay, dying out much later than the signal...due to time domain issues, same distortion percentage is not comparable between different transducers, as in some, the harmonics last longer than the cause, but that sort of discussion is for another time...

Cheers,

Alex

Hi Alex,

Are you sure the third order distortion measured is due to the headphone and not due to the measurement chassis vibrating. I've seen a wierd pattern on all innerfidelity charts of some tactile feeling headphone like Skullcandy crushers. If a driver breaks the thd needs to keep rising. But in those charts thd stabilizes down. Which leads me to believe that the measured distortion is more into the measurement system rattling than the headphone distorting. In a normal human head, this tactile sensation will be felt on the cheek through earpads.

I care so less about "harmonic" distortion. Were you able to measure transient envelopes and intermodulation distortion?

Also, I had earlier sent you mails regarding a different drive schematic for these if you were to be interested. Not sure if it reached you. Currently going through knowledge bases for a while now.

 

[nishan99]

Hello everyone

I have a simple question about these headphones, do you see them when you put them on (are they in your field of view)?

 

[David Aldrich]

Hello everyone

I have a simple question about these headphones, do you see them when you put them on (are they in your field of view)?

No, can’t say I’ve ever noticed any part of them in my field of view. I do wear them as far back as reasonable because that sounds best to me.

 

[Aleksandar R.]

Hi Alex,

Are you sure the third order distortion measured is due to the headphone and not due to the measurement chassis vibrating. I've seen a wierd pattern on all innerfidelity charts of some tactile feeling headphone like Skullcandy crushers. If a driver breaks the thd needs to keep rising. But in those charts thd stabilizes down. Which leads me to believe that the measured distortion is more into the measurement system rattling than the headphone distorting. In a normal human head, this tactile sensation will be felt on the cheek through earpads.

I care so less about "harmonic" distortion. Were you able to measure transient envelopes and intermodulation distortion?

Also, I had earlier sent you mails regarding a different drive schematic for these if you were to be interested. Not sure if it reached you. Currently going through knowledge bases for a while now.

Hi Manuel,

The way I measured is that I stick an electret capsule mic into my ear canal and put the headphones on.
There could be all sorts of problems with that setup, but it's the closest to what would be the usage scenario, so whatever is happening with parasitic vibrations, it would probably happen in use.

Sure, I measured bursts and IMD, just for fun. It follows the falloff towards 500Hz just like THD does, so it doesn't give more usable data.
In transducers, the IMD will show no surprises as with amplifiers, as there is no increasing non-linearity as you go towards small signal (crossover distortion and such), so it is very strongly correlated with THD and it is mostly governed by the same mechanisms as THD.
Anyhow, there are several standards for measuring IMD and I still don't know how IMD reflects in what is audible as a problem with transducers, so I don't publish such stuff.
It's great for RF, though, when you need to directly express the number for selectivity of a radio receiver, for example, but I don't see much use for it with transducers. For Amps that depend on lots of feedback, maybe, as you can see how the noise floor looks like, if it's random noise or not, but in transducers, the THD is large enough that noise floor is never just a random noise, so it won't tell nothing new as THD mechanisms will govern the behavior if IMD.
Anyhow, digging deep with measurements is good when you need to solve audible problems with the transducer you're making. Because to my ears, the SR1a has the cleanest midrange I've ever heard on speakers or headphones, I consider that part of the work done. Having midrange THD better that 0.25% at 100dB, along with the cleanest impulse response in headphones ever, attests to the non-problematic midrange.
Simply, there was no reason to try to explain anything with IMD, as it follows THD, or burst envelopes, as they follow the Impulse response.

Speaking of audibility of distortion, I did a lot of testing for distortion in low frequency.
What I've learned correlates very well with what Axiomaudio published:

The explanation is here: https://www.axiomaudio.com/blog/distortion

There we see that below 40 Hz, the noise can be louder than the tone and we'll have trouble detecting it.
Also, up to 280Hz, the noise can be just 12-13dB lower than the tone and we'll have trouble detecting it.
Now, this is done with noise that doesn't correlate with music, so it's not THD. THD should be harder to detect.

In any case, I've managed not to do go that high with distortion, but had to stop reducing it somewhere to make a feasible product.
The goal was to get inobtrusive (if not inaudible) levels with 100W/8Ohm amplifier.
As you go higher with power, things will become progressively more audible until you reach the point of demanding more excursion than the mechanical limit is.
For Classical, acoustical Jazz, I'd say 150W is safe and modern stuff is safe up to 100W.

For driving the headphones, the requirement is simple. You have 0.4 ohms with the cable and you need to use EQ that will flatten the open baffle cancellation.
I think all that has been discussed before page 80 or so, of this thread.

Cheers,

Alex

 

[Stuff Jones]

Any update on the the timing of the Schiit custom amp for these and whether they will be available as a package without the interface?

 

[Zan.Tiago]

There was a mini-meet at The Source AV Design last Saturday where Schiit demoed the prototype "Weldenheim" direct drive amp for the SR1a's in a Jotunheim chassis more details at the Raal thread at forum.headphones.com. The Weldenheim was well received and it looks like Schiit may be doing a collaboration with RAAL-requisite to sell it when ready. Price may be around $1400 if it makes it to market.

Great news, thank you for the information!

 

[Zan.Tiago]

That's probably intentional as using two Vidars in mono-block mode is one of the preferred budget amp choices for the SR1a.

In the context of a private listening session at headphoneauditions.nl (great experience btw, well worth the trip to Amsterdam and the cost of the service), I had the chance of trying the SR1a and doing some direct comparisons with my current Abyss Phi TC setup (see signature), which I was able to replicate at the shop.

The amplifiers I was able to pair to the SR1a were the Chord Etude (100W/8Ohm) and the Thrax Enyo, a dual mono class A tube integrated with 50W/8Ohm output rating.



I would say the SR1a are an 'experience' of their own, and their trademark definition as Earfield Monitor is a really appropriate one.
Since the very first few seconds after wearing / listening to them you get this unique mix of headphone and near-field speaker feeling which I enjoyed very much, both in terms of comfort and fit and as a way to obtain a large and diffused headstage.

The most striking trait of the SR1a to me was their extreme micro-detail resolution capability, significantly exceeding any headphone I have ever heard, including the AB-1266 Phi TC. I would define this more as a 'technical feature' than a 'benefit', because (over)exposing microdetails is - to me - satisfying in the short term (the wow! effect) and as an analytical tool - like in a studio editing session, but not necessarily something that gets me closer to the reproduction of the live perception of the music.

I was impressed by the SR1a speed (especially with the Etude) and the sense of air between the notes and between the instruments.

In terms of timbre, I liked the midrange and treble most of all - while on the leaner side (better with the Thrax). The vocals, both male and female, were presented in a very realistic fashion and with no traces of sibilance and harshness which are sometimes a by-product of headphones with high detail retrieval and airiness. Abyss TC vocals sound, in direct comparison, a bit rougher and less 'real'.

As for the bass, the SR1a are not bass light in asbolute terms, and both the quality and quantity of their bass were above my expectations. However, I must admit that I missed a lot the sense of physical satisfaction - even euphoria at times - the Abyss are able to deliver through their deep, fat but fast and resolved lowest end.

By adjusting the earpieces I could manage to tune the balance between bass extension / impact and soundstage extension / imaging focus, but some tracks (organ, of course, but also some vocals with deep double-bass plucks) were simply not enjoyable to my ears with the SR1a after hearing them on the Phi TC.
Headstage, imaging, instrument separation were very good as well, but I preferred the Phi TC more cohesive and deeper staging. I had the feeling that the SR1a tend to present the music in an hyper-realistic, even mechanical fashion at times, which is somehow a different experience from what I get in a real concert venue, which the TC mimics closer IMO.

Among the two amps I tried, tonally I preferred the Enyo warmer / darker signature compared with the Etude, whereas the Etude won in terms of speed and bass impact. I was relatively surprised that the Enyo - rated 'only' 50W - was able to drive the SR1a well above my typical listening levels (80-85dB), with no feeling of being strained.

Overall, I really appreciated the SR1a and I am quite sure that with some more time with them (allowing better brain and mechanical adjustment) and perhaps with a further optimization of the amp pairing they could shine even brighter. That said, as I realize I am biased towards the Phi TC, I would not see the SR1a as a replacement to the Abyss, more likely as a complement to enjoy a different / unique way to experience listening to music through headphones (or Earfield Monitors ).

In the context of a private listening session at headphoneauditions.nl (great experience btw, well worth the trip to Amsterdam and the cost of the service), I had the chance of trying the SR1a and doing some direct comparisons with my current Abyss Phi TC setup (see signature), which I was able to replicate at the shop.

The amplifiers I was able to pair to the SR1a were the Chord Etude (100W/8Ohm) and the Thrax Enyo, a dual mono class A tube integrated with 50W/8Ohm output rating.



I would say the SR1a are an 'experience' of their own, and their trademark definition as Earfield Monitor is a really appropriate one.
Since the very first few seconds after wearing / listening to them you get this unique mix of headphone and near-field speaker feeling which I enjoyed very much, both in terms of comfort and fit and as a way to obtain a large and diffused headstage.

The most striking trait of the SR1a to me was their extreme micro-detail resolution capability, significantly exceeding any headphone I have ever heard, including the AB-1266 Phi TC. I would define this more as a 'technical feature' than a 'benefit', because (over)exposing microdetails is - to me - satisfying in the short term (the wow! effect) and as an analytical tool - like in a studio editing session, but not necessarily something that gets me closer to the reproduction of the live perception of the music.

I was impressed by the SR1a speed (especially with the Etude) and the sense of air between the notes and between the instruments.

In terms of timbre, I liked the midrange and treble most of all - while on the leaner side (better with the Thrax). The vocals, both male and female, were presented in a very realistic fashion and with no traces of sibilance and harshness which are sometimes a by-product of headphones with high detail retrieval and airiness. Abyss TC vocals sound, in direct comparison, a bit rougher and less 'real'.

As for the bass, the SR1a are not bass light in asbolute terms, and both the quality and quantity of their bass were above my expectations. However, I must admit that I missed a lot the sense of physical satisfaction - even euphoria at times - the Abyss are able to deliver through their deep, fat but fast and resolved lowest end.

By adjusting the earpieces I could manage to tune the balance between bass extension / impact and soundstage extension / imaging focus, but some tracks (organ, of course, but also some vocals with deep double-bass plucks) were simply not enjoyable to my ears with the SR1a after hearing them on the Phi TC.
Headstage, imaging, instrument separation were very good as well, but I preferred the Phi TC more cohesive and deeper staging. I had the feeling that the SR1a tend to present the music in an hyper-realistic, even mechanical fashion at times, which is somehow a different experience from what I get in a real concert venue, which the TC mimics closer IMO.

Among the two amps I tried, tonally I preferred the Enyo warmer / darker signature compared with the Etude, whereas the Etude won in terms of speed and bass impact. I was relatively surprised that the Enyo - rated 'only' 50W - was able to drive the SR1a well above my typical listening levels (80-85dB), with no feeling of being strained.

Overall, I really appreciated the SR1a and I am quite sure that with some more time with them (allowing better brain and mechanical adjustment) and perhaps with a further optimization of the amp pairing they could shine even brighter. That said, as I realize I am biased towards the Phi TC, I would not see the SR1a as a replacement to the Abyss, more likely as a complement to enjoy a different / unique way to experience listening to music through headphones (or Earfield Monitors ).

Thank you so much for share your experience in such a great way!

 

[PeteSTRADAMUS]

Any update on the the timing of the Schiit custom amp for these and whether they will be available as a package without the interface?

Yup, what he/she said.

 

[Aleksandar R.]

I'm not sure about the timing for "weldenheim". I know what Danny tells me and we didn't pick up the subject the last time we talked.
All I know is that I want one and I'm eagerly awaiting to get it!

About the package sans interface, my position is that we always send the set with the interface. That way, if anything happens to "weldenheim", you can plug the headphones into any old amp and be operational. Without it, you're risking having "dead" headphones because of dead accompanying electronics, and that is not the case with any other headphones out there. Even with stats, you can plug them in another amp for stats and get on with listening.

Danny's position is still unsure.

In any case, as long as the customer is aware that dead amp means dead headphones until the amp is replaced/repaired, I'm OK with the idea of offering SR1a sans interface.
If that's OK with you guys, we can do that and write a warning that explains this when making a purchase.

 

[Jozurr]

I'm not sure about the timing for "weldenheim". I know what Danny tells me and we didn't pick up the subject the last time we talked.
All I know is that I want one and I'm eagerly awaiting to get it!

About the package sans interface, my position is that we always send the set with the interface. That way, if anything happens to "weldenheim", you can plug the headphones into any old amp and be operational. Without it, you're risking having "dead" headphones because of dead accompanying electronics, and that is not the case with any other headphones out there. Even with stats, you can plug them in another amp for stats and get on with listening.

Danny's position is still unsure.

In any case, as long as the customer is aware that dead amp means dead headphones until the amp is replaced/repaired, I'm OK with the idea of offering SR1a sans interface.
If that's OK with you guys, we can do that and write a warning that explains this when making a purchase.

If a situation like that was to happen, a customer can simply buy the interface from your website, which is a better option, than to mandate customers to pay for a box in advance that they are not going to use and is going to sit idle, until they decide they don't want to use the weldenheim or something happens to the weldenheim, both of which should not be assumptions to start off with.

 

[Stuff Jones]

I'm not sure about the timing for "weldenheim". I know what Danny tells me and we didn't pick up the subject the last time we talked.
All I know is that I want one and I'm eagerly awaiting to get it!

About the package sans interface, my position is that we always send the set with the interface. That way, if anything happens to "weldenheim", you can plug the headphones into any old amp and be operational. Without it, you're risking having "dead" headphones because of dead accompanying electronics, and that is not the case with any other headphones out there. Even with stats, you can plug them in another amp for stats and get on with listening.

Danny's position is still unsure.

In any case, as long as the customer is aware that dead amp means dead headphones until the amp is replaced/repaired, I'm OK with the idea of offering SR1a sans interface.
If that's OK with you guys, we can do that and write a warning that explains this when making a purchase.

Not to speak out of place, but if you could offer an all-in-one end-game headphone experience at ~4k (sans interface) that would be super appealing. You could always offer the interface as a separate.

 

[Tugbars]

maybe it's a good idea to sell box & headphones for 3500$.(bundle deal). Headphones alone can be sold for 3000$ and the box for 700$.(the numbers are totally random) If something happens to the "weldenheim" customers can purchase the box.

 

[Aleksandar R.]

All good points, thank you!

I just talked with Danny and he's also for "everything optional", so there it is.

However, it's too early to say the exact numbers before some qty of Weldenheims is made to see the cost of the run.

Also, if we sell you the SR1a without interface but with the Weldenheim, we would have to use a larger case and a different foam cut to fit the larger Weldenheim and keep that in stock, but in general, the numbers you guys mentioned are in the ballpark.

 

[WilliamWykeham]

Taking a break from the land of Weldenheim, I've got an update on AHB2 impressions. @llamaluv and I combined forces this weekend for a deep dive comparison of bridged mono vs single amp. I had hoped to hear dual mono sounding just the same as a single AHB2. This hobby -- the endless upgrades, product comparisons, the bleed of cash into highly depreciating electronics - why can't I just find my TOTL setup, and let that be that? So with this hope for a null result we set them up in dual mono and gave it a listen. Result: my hopes were dashed.

Comparing dual mono to single amp, it's as if this mushiness and congestion gets cleared up and I'm hearing such fantastic separation of instruments - that was the main difference I noticed, much more distinct instrumentation, along with slightly improved soundstage. @llamaluv can potentially describe his own impressions but I think for him it was more a matter of a denser, rounder tonality.

We also tested out his Susvara in this setup and it was the first time the Susvara has ever spoken to me (I used to own an HE-1000 and liked that one a lot). It was like, OK I get it now.

In my opinion, if you're not going dual mono with the SR1a, you're missing out on heaps of performance.

 

[llamaluv]

Taking a break from the land of Weldenheim, I've got an update on AHB2 impressions. @llamaluv and I combined forces this weekend for a deep dive comparison of bridged mono vs single amp. I hoped to hear dual mono sounding just the same as a single AHB2. This hobby -- the endless upgrades, product comparisons, the bleed of cash into highly depreciating electronics - why can't I just find my TOTL setup, and let that be that? So with this hope for a null result we set them up in dual mono and gave it a listen. Comparing dual mono to single amp, it's as if this mushiness and congestion gets cleared up and I'm hearing such fantastic separation of instruments - that was the main difference I noticed, much more distinct instrumentation, along with slightly improved soundstage. @llamaluv can potentially describe his own impressions but I think for him it was more a matter of a denser, rounder tonality.

We also tested out his Susvara in this setup and it was the first time the Susvara has ever spoken to me (I used to own an HE-1000 and liked that one a lot). It was like, OK I get it now.

In my opinion, if you're not going dual mono with the SR1a, you're missing out on heaps of performance.

I am in agreement with these impressions. I also wish I could have cleaned things up a bit before you snapped this pic without saying anything (keke).

I wasn't particularly invested in the outcome of this test, but was pleasantly surprised at how apparent the improvements were to me. The best way I can describe it is that the bridged mono configuration sounds more "M-Scalar-like": More "rounded" transients, a more composed and relaxed presentation. While simultaneously more dynamic. I also sometimes noticed that certain music sounds "slower" than I was used to, if you see what I'm getting at. Another way of putting it is that the uplift in "transparency" (oh well, I try to avoid using that word) allows the qualities of the M-Scalar to become more apparent. I've been listening to this setup continuously for the last several hours (thanks @WW!) on the Susvara and Utopia and have been loving it.

In terms of "value", I think the improvements are line with what you could expect from a $6000 amp versus a $3000 one. And I'm therefore pretty sure I know where my next 3-grand of disposable income is going.