I was just listening to an interview with Danny and Alex, of RAAL-requisite, where they talked very briefly about:
These might make an appearance at CanJam in September - fingers crossed. And if not, it’s good to know that the first is still in the works and that another amplifier is planned!
Listen from ~1:18:30 for the new stuff …
Hmmm…THIS might force my hand to go to CanJam in Sept.
On the Audiophile Style pod, the founders of RAALrequisite share that they’ll be showing off their new CircumAural headphone and a new Tube Amp at CanJam SoCal in September.
A few quick takeaways:
Part of what customers pay for when purchasing RAAL-requisite is Danny’s extensive music background, experienced ear, and tuning.
I like Alex’s philosophy for his builds to get out of the way where he believes the gear can’t make the recording/music better than it is. This is similar to some of the best chefs and winemakers adherence to picking the best ingredients and just trying not to mess it up when cooking/vinifying.
Danny is bass sensitive.
I auditioned the SR1a and HSA-1b for a few weeks thanks to @MokhaMark. I very much enjoyed its technical performance, but the current iteration isn’t for me at this juncture. I look forward to trying the circumaural release.
Thanks for linking.
Wanting to occasionally use my SR1a at my desk (instead of sitting by the rig), I needed a longer cable for them. The peculiar ultra-low impedance requirements for the SR1a cable mean there is no way to do this with a simple, single headphone cable. It would be too heavy and bulky to work. Just the diameter of wire needed to get sufficiently low resistance for one phase/channel is larger than the cable-entry on 3.5mm TRRS jacks.
So I built an extension cable that runs from the interface to the edge of my desk, where it is clipped on to support it, and then the “normal” SR1a cable (either the RAAL-requisite supplied ones, or my own - which is what I use) from there to the headphones:
This let me use a suitably thick conductor to get the overall resistance down to keep the whole assembly under 0.05 ohms (at 5 meters), and still allow for proper geometry and shielding etc. It is still cryo-treated. I skipped the electron-beam irradiation as that’s more about reducing microphonics and increasing flexibility, which are not big factors here.
Getting the conductors into the connectors and making the pin-connections required some ingenuity, as did preserving proper strain relief, which added several hours to the build-time.
All ready, now, for the next couple of RAAL releases now …
How long is your extension cable?
When I ordered my SR1a, I requested a 20 foot cable from Danny instead of the default 3m. (This is their standard cable, not the silver that they didn’t even offer yet at the time I ordered.) The 20ft seems to work just fine. (Amp is the HSA-1b, FWIW.)
It’s 5 meters (16.5 feet) long.
I made my own cables for the SR1a. Since the only option to drive them at the time was via the ribbon interface (the HSA-1a, never mind the HSA-1b, didn’t exist yet), I wanted a cable that had lower impedance than that offered by RAAL-requisite. That has the effect of lowering the treble level some.
Cable resistance is much more important when using the interface as it is entirely passive in its implementation of the step-baffle compensation, and the higher the overall cable resistance the higher the treble level (easily measured, and talked about by Alexander back when the SR1a was new).
When using a Jotunheim R, or an HSA-1a/b the cable resistance is much less critical.
There’s no way to make a cable of sufficiently low resistance at 7 meters long (the extension, plus my headphone cable), even using pure silver, using a single wire gauge/type that would a) still fit into the sockets needed on the SR1a end, and b) not be too thick/heavy to be usable, so I went down this path.
Let’s me use the extension to listen at my desk, and connect directly to the interface when I’m sitting at my rig.
I could, of course, just use the HSA-1b on my desk*, but I find the Chord Ultima 5/Interface approach sounds better, and it doesn’t take up any space on my desk.
*Which raises the question: “What to do with my HSA-1b?” For now, the answer there is that it’s in a second rig, driving the SR1a, conventional headphones, and electrostatics (via an iFi Pro iESL driven off the HSA-1b’s speaker taps.
To sub or not to sub; that is the question.
I’m going to put together a slightly longer review of my time with the SR1a in a couple of days, but right now, I was hoping to reach out and ask if anyone here has had success pairing a sub with the SR1a, and if so, how they did it.
Long story short, I’m absolutely blown away by the detail and staging of the SR1a, but the lack of bass and room information (at sane listening levels) is a bit of a deal breaker for me at the moment. Yes, if I turn things way up, it comes in, but then the macrodynamic punches are at unhealthy levels. I’m willing to do something a little crazy to offset that weakness, but wanted to ask if anyone here has tried. My current (possible) plan is to get a tube speaker amp (in discussions for a used PrimaLuna Evo 400 integrated), the RAAL transfer box (currently on Jot R), and a REL sub.
Am I nuts?
Edit: I also just discovered that the Jot-R’s passive preamp out can be active at the same time as the headphone out (I had somehow thought it was one or the other, but confirmed that’s not the case). As such, I think I could fairly easily pair this with a small sub like the KEF KC62 or SVS 3000 Micro. This would allow me to try the sub route without blowing up my current rig or requiring the transfer box, so is likely something I’ll try.
A large backpack or a chest harness…???
This use case brings to mind ancient forced-feedback video game interfaces. Joysticks would resist movement or rumble, steering wheels would change resistance as tire grip broke, and speakers were built into chairs. This partly lives on with vibration in game controllers today.
Bass = moving mass or using vibration to simulate the effects of bass. Yes you can buy a sub and deal with all the placement issues they involve. They have a mixed record even with speakers. You’ll be tied to a sweet spot, but that may be okay. If not a REL or similar, wear a de facto mobile sub such as the haptic device below.
There’s no replacement for displacement.
I have seen a few online posts about adding a sub in with the sr1a so you’re not nuts there. Unfortunately I dont know exactly how they integrated it into system.
One of the reasons I avoided the sr1a was for a situation like this, having to throw money at something to compensate for a “flaw”. Some are OK with the bass levels as is; however, Ive had enough sources, now including yourself, be unimpressed with the overall balance to an extent that making this kind of additional effort seems like a requirement. Personally not interested for a number of reasons. So maybe nuts there?? 
I dont see anything wrong with your planned chain but I haven’t pondered that question to any great degree.
Shahrose over @ Head-Fi has done it…and talks a bit about his setup here…
Yeah, my first instinct was to just move on from the SR1a, but the mid range and up is just so damn good, I can’t help but want to see if I can “fix” it. Like you said, it’s a little annoying to have to try to do that, but at the same time, plenty of us spend more money on tube rolling alone than the cost of a perfectly solid sub, so I figure it’s probably worth a try. 
Fair enough. It’s just an oddball of a can.
On one side it has S tier level qualities that by itself isn’t good enough to overcome its standalone shortcomings for many, but still good enough for people to go and seek out an external solution.
Just another means of “tuning”.
Move on and wait for the circumaural SR1a…
Adding a sub-woofer is one way to add bass to the SR1a. You can do it with other headphones too. And if I was going to do it for one, I would likely do it for all. And it is something I’ve tried, since I have the subwoofer anyway. But it’s not something I’d use routinely as I’m in the camp that says if I’m going to use a sub-woofer, I’m going to listen on speakers instead of headphones anyway.
That aside …
There are other ways to improve the bass response of the SR1a.
The first, and most obvious, is via EQ. The SR1a are basically flat to about 37 Hz, assuming the wings are closed (almost, or actually, touching your ears). They do 20 Hz at -6 dB in that position. There are a coupe of approaches to addressing this:
You can apply EQ to bring that level up. I did it using a couple of filters to keep the response flat. If you want to match the Harman curve (I don’t, but some do), it’s a bit more of a challenge since you’re going to need to raise the low end by so much that it will almost certainly cause excursion issues*.
It will sound counter-intuitive, but you can apply an EQ filter to essentially eliminate the bass output under, say, 40 Hz (some people liked it better chopped at 50Hz in the comparisons I’ve done). Yes, this does reduce low and sub-bass output to zero. It’s not an approach to use with EDM or other bass-heavy music, but it does tend to result in a cleaner delivery and more impact with music that are not so bass-focused. The counter-intuitive part is that it will make such music seem to have better bass presence, since the bass that IS there is cleaner and isn’t being “disturbed” by the ribbon trying to break the laws of physics.
Both approaches are free to try if you have Roon or use a player than can run EQ.
Another approach is to use a convolution filter to adjust the response of the SR1a. This is, for the most part, a fancier, more precise, way of applying EQ. Doing this requires playback software that can handle convolution filters (e.g. Roon does it using a built-in function, some other players need a plug-in). And then you need to either build or buy a suitable filter.
Building/generating your own such filter is beyond the scope of this post, but there is a good option you can buy. That’s the trio of convolution filters Mitch at Accurate Sound developed. The only real issue with which is that there is not, as far as I am aware, a way to “try before you buy”. And you’ll need to email him to buy them.
I have not, personally, purchased them. However, I do have a friend who has, and I’ve recently spent some time listening with those filters enabled (via Roon). One has a bass-lift applied. It’s easy to hear the difference with/without them, I think they make a useful and worthwhile difference. And I’d say they’d an improvement overall for most listeners.
The reason I haven’t bought a copy for myself (and consequently do not have a copy), is due to the potential conflict if/when I release my tool to make building such filters (to apply both standard FR EQ, as well as other “effects”) both easy and mapped to your own hearing response and preferences, and the fact I have generated my own such filters in the process (and since I built them for me, and my tastes, I like them a bit better than Mitch’s … his target is likely different to mine).
…
It’s possible to modify the Ribbon Interface to alter is compensation profile. It’s also possible to attempt to “tune” the response via amplifier rolling, but once you get enough power this seems to have very minimal effect (absent gross errors in amplifier linearity).
The initial performance metrics I heard quoted for the circumaural SR1a suggested that its bass performance was flat to 30 Hz, and then starts to roll-off again. So it should have more presence there than the current SR1a, but it was not stated as to how much additional roll-off there was down to 20 Hz.
No idea if that will hold for a production version, if there was missing context, if it was misstated etc. The LCD-R clearly show it’s possible to do a ribbon-like driver (it’s really a 98% trace coverage, ultra-low-impedance, planar) that has proper bass … so here’s hoping!
*You can always lower the higher frequencies to get the same profile, but that’s more involved in this case and won’t change the level of bass excursion for a given listening level anyway.
That haptic tacsuit suit looks interesting, but adding that to a Raal won’t do anything for the bass below 33hz that’s audible will it? Wouldn’t you need that vest and a sub for the full spectrum?
Thanks so much for the thoughtful and detailed reply, @Torq !
Great call. This is the first thing I did upon receiving the headphone and feeling unsatisfied with the bass. As you mentioned elsewhere, the bass quality is fantastic, but with the bottom seemingly entirely dropped out, the overall picture didn’t seem right. I had never EQ’d headphones before, but I used Roon’s Parametric EQ to bring the bass up a few dB and the treble down a few dB, and that got me to the point where I started enjoying the Raals, at least for a certain selection of tracks.
This, I have not yet tried, but may have to give it a shot!
I totally should have mentioned this in my initial comment, but I did indeed spring for Mitch’s convolution filters fairly quickly, and I found that they greatly improved the presentation throughout the entire frequency range. I now exclusively listen with his filter (#3, for those who have it) when listening with the SR1a. While the filter does bump the bass a bit, and it helps, I’m still not quite satisfied with it.
A few hours ago, I came to terms on a used KEF KC62 subwoofer, which I plan on hooking up to the Jot-R’s passive preamp out, so this should be a fun little experiment, and I will report back!
Hi @andris
I sometimes use a sub-woofer with my SR1a, and found this device very useful for controlling the level from the desktop, rather than having to constantly crawl to the back of the subwoofer to make changes, and you can mute the whole thing if you want. You can use this straight out of your DAC in that case, or as you mentioned the passive outs of the Jot R. This way you can adjust independently of the Jot R volume and get the desired level for various genre. For example, I like a very high level of bass for reggae even at modest listening levels, and with the Behringer, I can adjust without leaving my seat.
Thanks for the suggestion, @MokhaMark! This does seem super useful. I might be missing something, but is this only balanced? I’m all single ended at the moment. Maybe I could run it w/ adapters? In any case, I’ll see how things go w/ the sub, and will absolutely keep this in mind if I find myself crawling under my desk a lot. 
Sorry, I thought you had the Jot R which has balanced out, but your sub-woofer may not have an XLR input.
But you can get the same function from a Schiit SYS in single ended.
