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Post by speedysteve on Mar 22, 2023 20:10:53 GMT
So,
Zen though Gustard U18 results are in - it muddied rather than cleaned up. Zen on its own definitely better!
I'm back on Ultrarendu / Gustard now.
I'm going to try the optical SPdif in a minute - just have to dig out the semi exotic connector I have squirreled away somewhere. Ah yes, in the rats nest box of cables etc, I keep for a rainy day🙂
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Post by speedysteve on Mar 25, 2023 14:12:37 GMT
This is long but might be of interest.
Having settled in to the greater resolution of the new streamers / reckockers and a quieter galvanic isolated lifestyle...
I got curious as if there was more to come from Najda. The DSP / flexible crossover configuration / time-aligner / gain control / 5 stereo channel manager, all in one box etc.
Way back, 10 years ago in fact, I started computer controlled DSP management of my then active amp'd 5 channel horn system. It has been a thoroughly rewarding and ever explorational, learning, brain power challenging, journey.
It kicks anything you could reasonably do passively totally into touch. The flexibility and configurability as well as respected sound quality was the attraction. Replacing layer upon layer of caps, inductors, L-pads, Zobels etc yielded new sound quality options to me.
Not only that, joining the community of like minded DIY'er experts who set the requirements, and implement it's use in many different ways.
Other options are still not appealing to me. Camilla-DSP a PC or Linux powered SW development could be a contender. miniDSP had been dissed by a few SQ wise. Perhaps it is better these days? Other options are megabucks / have fallen by the wayside.
Right, back to the subject matter of this post.
Could I get more from Najda?
Back 10 years ago Najda arrived with 3 passthrough setups. All they do is ADC to DAC. These covered the 3 sampling rates it's capable of. 48KHz, 96KHz and 192KHz.
After building my Najda I tested it for transparency in my existing analogue setup. I was using a Puresound valve pre, fed by Teac (tank) transport and DPA enlightenment Dac.
48KHz sounded low res. 96KHz sounded fine. 192KHz.. I was not tuned in to hear any benefit, with my then analogue system, the drivers I had etc, or perhaps there was none?
Once set up with my requirements on X/O points and slopes, time alignment, some room correction etc it was clear 96KHz was the one since 192KHz used a lot of processor horse power, adding in my requirements overloaded the processors! Can't be run like that. Everyone told me 192KHz would be a stretch on multi channel.. a 2way yes, even a small 3way yes, all way - no way!
FF to now. I wondered if 192KHz might yield anything - why worry about it now?
Well, I've got renewed enthusiasm for my system, I've enjoyed the streamer adventure, so new ideas are kindled.
My current room has no DSP room correction fiddling on anything other than the tapped horn channel (sub 90Hz). I only cut dB, never add.
I decided to try 192KHz sampling.
Knowing my way around Najda's setups SW helps. I've kept up with it, even building and configuring a few for others..
Started from scratch with a 192KHz fresh setup. Transposed all the settings from the current 96KHz setup. Double check everything..
Load it up...
Core processor 1 was way into the red. 115 - 120%! Processor 2 a bit so.
I started removing the room corrections that I thought I could live without😂 Not enough, then changed the slopes on the 2 bass channels from 48 and 24dB / octave to 24 and 12. That did the trick, I could at least listen, and there were no changes to the upper 3 channels...
Listened yesterday evening. Hence the hi-red, What are you playing now post.
Nothing short of a revelation..!
Everything sounded calmer, more complete, relaxed, on point - don't know how to explain it.
Well, other than the bass boom! The lack of a couple of key freq cuts meant that anything south of 90Hz, risked exciting the room modes of 78Hz, 55Hz and 29Hz. I'd got away with leaving the 29Hz cut on, and it is the mother load of boom on certain key tracks.
I was able to compare instantly 96KHz set up with 192KHz. The difference was to my 'now ears', not insignificant!
Avoiding bassy challenging stuff, I could compare and evaluate!
I simply had to have 192KHz sampling in my hifi life! From now on!
To be continued..
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Post by speedysteve on Mar 25, 2023 15:53:36 GMT
Having slept on it. 2 ideas came to light.
1. I've got two complete and working Najda. Perhaps could chain them (again, as I'd made a test doing this before). That way all the sub stuff could be on one and the other channels on the 1st main unit. Hmm, SQ due to analogue out and then into the other Naj etc..
2. Load share between the processors. I was sure I'd read about it somewhere.. Could not find it.
A quick post on the Najda thread on DiyAudio forum gave the answer in 30 minutes🙂 I had for reasons of simple output feeds to the amplifiers, been using core processor 1 to do the first 2 channels and core 2 the rest.
Reconfiguring the setup so the 1st processor does all the left channel outputs and the 2nd processor the right channels, would balance them.
I did this for both 192KHz and 96KHz setups. I put back the minimum necessary room correction.
Checked everything several times.
Then I had to change the position of the outputs feeds on Najda to the amps. Not a nice logical line anymore.
1 and 5 are the tapped horn subs 2 and 6 the lower mid bass 3 and 7 the mid 4 and 8 the upper mids...
Looks quite logical when you see it like that.
But it's
7 5 3 1 8 6 4 2
In reality.
That done, I loaded in the 192KHz setup first. Wow, both processors at 83% and stable.
I then, starting with all off tested each channel pair, starting on really low volume, checking left and right.
Yep, I'd got both the setup and feeds to the amps right.
Store the setup as a preset. Load the 96Hz one. Ditto.
Now I can really evaluate apples vs apples.
Same X/O slopes, same room correction etc.
Very interesting to switch between the two.
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Post by MartinT on Mar 25, 2023 17:21:55 GMT
I find the Norah Jones track Come Away With Me in 24/192 a fantastic example of brushed cymbal work where no lesser resolution sounds as natural.
Give it a try.
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Post by speedysteve on Mar 25, 2023 17:46:40 GMT
After a good many tracks..
Listening is not pretty for the 96KHz setup. Edgy as F*** on some tracks, in comparison.
Some are less damning, but still less preferable in general.
I prefer 192KHz across the board. It's a different presentation of the same music!?
Edit: forgot to say, CD quality, 16/48, 24/96, 24/176, 24/192 music from Qobuz, they all sound different / better.
A nice free upgrade.
Even got Marie to do a little blind test.. A piece of card blocking my view of the setup on the Najda display, my leaving the room, no track playing. Marie selecting one of the 2 setups available at random, she noted the track, res and setup selected. My returning, listening, marking what I thought. Stop that track, I leave the room again. Something else is cued up in Bubble, the setup is changed or stays the same, I don't know.. I return, play, mark up what I though. Did that over and over. Sometimes revisiting the same track, same setup or not. I had no idea. Marie kept record of the order of what she played, what res the tracks were in Bubble UPnP, CD, 16/48, 24/96 and 24/192. Even one 24/176 and if course the setup used.
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Post by MartinT on Mar 25, 2023 18:43:23 GMT
Reminds me, I will try some hi-res tracks with the Gustard DAC in NOS mode tonight.
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Post by speedysteve on Mar 26, 2023 11:36:29 GMT
Reminds me, I will try some hi-res tracks with the Gustard DAC in NOS mode tonight. What was the result? I've only had one NOS dac, a long time ago. It was laid back! I've dialled in the bass some more. Can't get enough of Najda running at 192KHz. It definitely gets more out of the Ultrarendu / Gustard U18 duo, and vice versa.
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Post by MartinT on Mar 26, 2023 11:45:30 GMT
Indeterminate. I think the Gustard's oversampling mode is fine and I didn't hear much if anything when switching to NOS mode with 24/192 material.
I did, however, hear rolling off of the top frequencies when using NOS mode with 16/44 material, as you would imagine.
I suspect NOS is better for super-high upsampled feeds from the likes of HQPlayer. I shall be leaving it disabled.
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Post by speedysteve on Mar 26, 2023 14:51:17 GMT
Yes, that would explain what I experienced. Would have only been 16/44 CD back then. Zzzz
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Post by speedysteve on Mar 27, 2023 20:16:31 GMT
I've been trying to reconcile what I'm hearing with the upsampling rate change from 96KHz to 192KHz.
Searching around I found this short and sweet explanation.
"sample rate can be 96 and 192 kHz for improved DSP calculation precision"
That succinct sentence cleared out up.
This has nothing up do with the recording. It is seemingly often interchanged and confused.
It's all about the precision the DSP box can operate at. That's why 16/44, 24/44 etc, 24/96 and 24/192 all sound different / better with the DSP box set at 192.
It's not that we (I) can hear the difference between those recorded formats.. In all probabilty I don't think I can..
It's that I can hear the improved precision / resolution my DSP box operates at, on all of them, when it's doing it's thing.
Does that make sense?
Edit: Another longer take on it..
"DSP does profit by increasing the precision. Doing all calculations with 32 or better 64 bit keeps down the quantization error. As DACs only accept integers, as DSP uses a precision much higher that 16 or 24 integer, in the end any DSP action has to be dithered. Here a 24 bit recording has the advantage as with 16 bits the dither is at -96 dBFS but with a 24 at -144 dBFS You have to play FFF loud to make something at -144 audible if possible at all. To sum up, DSP is about doing calculations This has nothing to do with sample rate except that sample rate might be a limiting factor (time) This has all to do with precision, the more bits the better"
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Post by speedysteve on Mar 28, 2023 6:41:30 GMT
As part of that research I found out that miniDSP's 2x8 and their 2x10 (2 inputs, 10 outputs and 4 x 10) only did 24/96 max. Same for the much more expensive DEQX.
miniDSP does say the 2 x 4can do 192KHz these days. 2 x 8 quotes 96KHz still. Their multi channel solutions are drying up I'd read.
Najda was ahead of its time back in 2013!
I'm not sure if the V1.3 board I got in 2018 has a bit more horse power then the original V1.1 board, I had since 2013? It might explain why I can get it to work fine at 192KHz though.
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Post by MartinT on Mar 28, 2023 8:08:29 GMT
That makes a lot of sense, Steve. What processor and DAC does the Najda use?
Lot of calculations in order to do DSP across the frequency bands.
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Post by speedysteve on Mar 28, 2023 10:19:50 GMT
That makes a lot of sense, Steve. What processor and DAC does the Najda use? Lot of calculations in order to do DSP across the frequency bands. I can't remember the dacs. I did toy with swapping them out, some have even gone external, multiple Lampizators and other exotics - not low hanging fruit though. The general consensus was that the dacs were well implemented. There are 2 main families of DACs, I read somewhere. Najda's are the sort that works fine with ChromeCastAudio (24/96 bug) though 🙂 Mutec reclocker was not compatible with CCA! = Dropouts at anything above 16/44 music. I could find out what the processor is... I was reading that miniDSP multi channel, could run at 192KHz but with reduced PEQ / X/O etc capabilities, so the developers never opened it up to end users.. The 2 x 4 they did it seems. I remember Najda creator Nick, saying that upping the processor power to do propper FIR at tens if not hundreds of thousands of taps (needed for true performance), would have pushed it into a whole other price category. Esp at 192KHz! You halve the taps available with every Freq doubling.. There's just not a big enough market for it. Although the few who go to the rarified 4 channel, or 5 channel would probably spend what it takes (within reason).
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Post by speedysteve on Apr 14, 2023 16:21:36 GMT
This evening's messing about will be to set up a pair of Sonos One speakers, as a stereo pair and listen to them at the correct listening height / position, in my music room.
Using Qobuz at highest Res Sonos allows (upto 24/96).
Lets see how long I can't resist turning the main rig on.
Ladies & Gentlemen, place your bets...
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Post by mattspl on Apr 14, 2023 20:00:04 GMT
I have a feeling they will sound very good
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Post by speedysteve on Apr 16, 2023 16:18:28 GMT
I have a feeling they will sound very good You were right. I actually listened the whole evening! Summing up the Sonos One stereo pair; The mid bass, mid and upper registers are pretty good. Stereo image present✔️ Instruments that should be out wide, are. Ripping rock guitars do rip quite a bit. Plays down to 40Hz with a lot of presence. Even complex rock was reasonably composed. Caught a light sneeze - Tori Amos, was a half dogs dinner, but I've heard Hifi rigs murder it more! There's a rolled off presence to 35Hz and oddly on some material 30ish Hz very rolled off, but not on others? The music is surprisingly enjoyable. Obviously lacks the speed, clarity, dynamics, detail, sheer grunt across all frequencies, texture of the mid bass and deep bass, let alone room shaking (with quality) / slam of my big system. If I added one of their their subs it'd be more slamful🙂 Interesting experiment. Qobuz within Sonos is very easy to use (playlists already set up in the Sonos app), and who knows - might get Qobuz-connect fairly soon?!
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Post by speedysteve on Apr 16, 2023 20:09:48 GMT
+ it makes you really appreciate what you've got when you go back to big rig, and crank it up!
I did similar with my Nad 3020 and pair of Mission 700s (was my garage system), many years ago (10?), at the old place, vs the then horn system. I was much more disappointed by the Nad / Missions tbh.
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Post by mattspl on Apr 16, 2023 21:57:28 GMT
Sounds like a good result
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Post by speedysteve on Apr 20, 2023 12:44:39 GMT
I'm still enjoying Media Server Bubble UPnP, optical lan insert, into Ultrarendu, into Gustard reclocker. Definitely all keepers.
I'm going to be building some 1.6m long, exponential bass / mid bass horns with some nice 12" drivers. They will be vertically arranged.. 75Hz to 350Hz.
I will get to try them before they find their new home..
Never a dull moment
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Post by MartinT on Apr 20, 2023 13:12:04 GMT
Are your lathes getting bored, Steve?
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