exaU2I - Multi-Channel Asynchronous USB to I2S Interface

[Bunpei]

Originally Posted by exa065

Do you have any suggestions about this case?

As I am neither supporting staff of exaDevices nor that of Twisted Pear Audio, please regard my consideration as just a private speculation.

I think the frequency of oscillator device on the Buffalo II board has no direct relation with this issue. However, TPA might have changed ES9018 register setting for DPLL bandwidth parameter at the same timing when they upgraded previous 80 MHz oscillator to new 100 MHz one.
In my case, two new Buffalo II boards with 100 MHz oscillators shipped this year suffered the similar problems. After replacing the new MCU with old one that came with an old Buffalo II board with 80 MHz oscillator, the problem disappeared.

If you want to confirm this, one possible way is detaching the MCU from the board. This means you run the ES9018 DAC chip with full default settings. If you find no unlock problem then, the cause must be the MCU.
However, please remember that a sound volume will decrease in this case because of input distribution setting of the default set.

There may be two possible measures to solve the problem when my speculation is correct. One way is to obtain a MCU of old version programming and another way is to prepare your own MCU that can set appropriate register values on the DAC chip.

Bunpei

[exa065]

Originally Posted by Bunpei

As I am neither supporting staff of exaDevices nor that of Twisted Pear Audio, please regard my consideration as just a private speculation.
Bunpei

Thank you, Bunpei. I appreciate your help

[AR2]

Originally Posted by rsdio

If you want to emulate a passive analog crossover made with capacitors and inductors, then Apple provides low-pass and high-pass AudioUnits for free - with the operating system. You just need an application that can host them.

Thank you Rsdio for the advice. I did almost the same, but through the Logic. I was planning to share it here, so here is the opportunity. Hopefully someone could use it, just like I learned from you and RayCtech

My situation, and believe anyone else's doing active on Mac is that although there is an exceptional application - Pure Music that hosts its own crossover, it doesn't cover everything. In another word, I could play my files from the hard disc, but I cannot simply slip CD into and play, or I cannot play streaming radio stations. Now, for the highest fidelity I could do no better than PM. Plays from memory, plays easily FLAC files, uses iPad to control, and uses iTunes for file management. Awesome, but sometimes I just want to stream my favorite Absolute radio station... or pop fast CD. So what than if my crossover is hosted by Pure Music?

I used Jack for rerouting to Logic that is hosting my plug ins. From Logic I go out to whatever my output is, for now RME card, soon replaced with I2S to USB card. I tried very popular SoundFlower, but that did not work for me. Instead when I tried Jack it work flawlessly, and it comes with good documentation.

Logic is an awesome app, and plug ins that comes with it are really good. As far as I am aware, there are no crossover plug ins for Mac, but as you suggested using low shelf, high shelf or bandass filters do a perfect job. As you could see, I was able to control the angle of the curve in dB just like with any crossover, and filters used are linear phase. The amount of additional filters that could be used if desired, such as room correction or similar is limited just by memory and processing power.

This way my crossover is independent of the music playing apps, and I could combine various players for various needs. In my listening tests I did not hear any difference comparing to regular crossover (the one implemented in Pure Music). I am happy camper so far.

[rsdio]

Originally Posted by AR2

I used Jack for rerouting to Logic that is hosting my plug ins. From Logic I go out to whatever my output is, for now RME card, soon replaced with I2S to USB card. I tried very popular SoundFlower, but that did not work for me. Instead when I tried Jack it work flawlessly, and it comes with good documentation.

Logic is an awesome app, and plug ins that comes with it are really good. As far as I am aware, there are no crossover plug ins for Mac, but as you suggested using low shelf, high shelf or bandass filters do a perfect job. As you could see, I was able to control the angle of the curve in dB just like with any crossover, and filters used are linear phase. The amount of additional filters that could be used if desired, such as room correction or similar is limited just by memory and processing power.

The shelving filters are not appropriate for crossover use, but I see that in Logic you are actually using the high-pass and low-pass that are appropriate.

For folks who have not purchased Logic, but who perhaps have installed the Apple developer tools, you might consider AULab. It is a free application from Apple that hosts AudioUnits and can work with multichannel hosting. You should be able to combine it with Jack, although I have never tried this combination. I bought a license for Logic Pro, but I often use AULab for real-time processing or analysis, so I thought I would share this option for folks who do not want to pay.

[Ludomaniac]

Just a little note of experience with my exaU2I and Buffalo II DAC.

I downloaded some music from High Resolution Music DOWNLOAD services .:. FLAC in free TEST BENCH, its in 24BIT/192kHz res. With my exaU2I connected to the Buffalo II DAC I tried to play this music using Foobar2000. The sound was glitching every other second and the glitches were like this during a couple of seconds: . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . .
if you understand what I mean, it went like in a loop before it sounded perfect in a couple of seconds before it started all over again...

I tried everything, playing files locally instead of from my network drive. I also tried to increase the buffer size, but nothing really worked...

Then I noted that someone talked about the firmware on the Buffalo II DAC, that it had changed somewhat during the shipments...

So this is what I did, note that my friend Oblivion tried this before me...:
I took out the firmware chip from the Buff II DAC, then powered it up all over again and started to play the music with 24BIT/192kHz resolution. Guess what happened!! I sounded perfect with no glithing at all!! I haven't got a clue why they release such a firmware on the DAC without properly testing, but this solved anything for me. Removing the firmware did the trick. And it still sounds fantastic!

Anyone else with trouble like this?

[Bunpei]

Originally Posted by Ludomaniac

I haven't got a clue why they release such a firmware on the DAC without properly testing, but this solved anything for me. Removing the firmware did the trick. And it still sounds fantastic!

Anyone else with trouble like this?

Just about two months ago. I posted the issue on their support forum.
DPLL Bandwidth setting on B II - Buffalo DAC - Twisted Pear Audio Support
However, I have received no answers from them so far.

Any DPLL Bandwidth parameter other than "default best" is very hard for any transports of I2S output to catch up because the DPLL frequency might be 64 times higher for I2S than that of S/PDIF.

[exa065]

Supra was unable to make any progress with his Buffalo II. Removing the MCU in his case produced only silence.

[qusp]

yeah well everything is set to defaults this way isnt it?

AR2, great to see you are having success with logic, you can also get convolver for logic for room correction, its a bit of a processor hog, but does the job very well. for logic you can also get hardware acceleration for the plugins if you wish to use higher resolution, or more channels. i would recommend waves also, which has a superb eq. you would only need the basic set, not diamond, or whatever the top level is these days.

you can get an ipad app for logic control also, which would make it easier to sit in the listening position when doing any adjustments

[qusp]

hang on AR2, which rme have you got? depending which, you can use totalmix to route an output back to the input without wires and access the audio that way without needing jack at all. just control click the channel strip of the output (see below) that has the data you want playing so that it turns red, then in logic you set the outputs of your crossover to the channels after that. you lose 2 channels, but you dont need to use another application. then as you are probably doing, you hit record and pause to process any audio playing through the plugins and assign your channels. make sense? the output from the bounce will be seen at the corresponding inputs, so to monitor a bounce from channels 1 and 2 as here, from memory they will be available on input channels 1 and 2. if thats wrong just play till you get them, or send me a pm and i'll double check, its been a while since i have used it in this way.

[Bunpei]

Originally Posted by exa065

Supra was unable to make any progress with his Buffalo II. Removing the MCU in his case produced only silence.

Does he configure analog output of his Buffalo II for Dual Mono?
Does he set input S/PDIF switch position at ON?
Which frequency does his master clock Crystek oscillator have, 80 MHz or 100 MHz?