Allo Boss DAC review

Thanks Johan!
I can safely get it then.

I have another question regarding the Allo Boss. The PCM5122 DAC from TI used in Boss, TI states the following:

“Members of the PCM512x family integrate preset audio processing functions with programmable coefficients, allowing developers to change the characteristics of the interpolation filter, speaker EQ, dynamic range controls, and average volume control in their products.”

The “speaker EQ” I’m interested in, as it can give major improvements correcting the speakers EQ to the room. Could the Boss be programmed using a room correction program to measure the room acoustics and then input the EQ settings into the PCM5122?

I guess it´s not set up for that right now, but what can be done now, if any?

Kind regards,
Jesper

Hi Henry,

I’ve replied to your post on our forums, please see below:
http://dietpi.com/phpbb/viewtopic.php?f=11&t=1480#p6163

Thank you Dan. I hope that a solution can be found at some time.

Frankly speaking…its very difficult to program the DSP functions from TI ic… you need to download some software (and its hard to get TI people to reply) and then learn how to use it.

Thanks for the answer Johan. Maybe not the answer I wished for though. TI ought to learn from companies like Apple to make “developers kit” so that their hardware products can get even more useful. Tis is the big reason for their success!

Room EQ abilities that can be done but are ignored seems like waste of resources to me, right?

I guess, if no one asks nothing happens, but if you show interest into it, it could make a difference. I understand that companies like TI of course, like many companies, look to help their big customers first.

You have very competitive products today, fairly new to the RPi sector. What I really like is the way you listen to your customers - you have too much to win on doing that! Just see the feedback you got from Janis to correct your product, going from good to excellent. Then think if your products suddenly had room correction abilities - that would for sure beat the competition!

@allo.com - I agree with he comment from Jesper about your willingness to listen. But to understand the problems with the questions I asked you and Dan from DietPi: With the driver for the Boss, 352 and 384 kHz is red, DSD 64 is yellow and the rest is red in Roon. Although the Boss hardware-wise is ready for 384, and possibly also DSD 128 and 256, it is not possible because of software problems with TI. Is that the case? Or is it a problem with Linux in the current version?

The main problem is that DSP cycles in DAC ic are very limited…and to do room correction you need lots of processing power. So its not possible.

Besides why would you do that in DPS? You can use a software like BruteFir and do it directly on the CPU of RPI.

No problems with the TI, but 384Khz is no part of Rasbian. There was a guy (brilliant) CliveM that wrote the code , it was never accepted in rpi mainline (never submitted)…so most audio distribution took his patch and used it. However , every new version of Raspbian , makes it more and more difficult to use that patch. I think that 384Khz will completely disappear from RPI soon enough if Clive is not coming back.

Thanks again Johan for enlightening into some of the valuable implications into doing both EQ and 384 kHz. Now I read up on some things in the mean time.

When it comes to sampling rates (384 kHz etc) there is the interesting fact of how small time differences we can hear. Like some displays are said to be “retina” display, meaning small enough pixels to not be able to see the pixels by the eye, there are the same fact of sample rates. When the sample rate is 192 kHz each time between the samples are 5,2 microseconds. Our hearing of time differences are very good, about 6-7 microseconds, which makes a sample rate of 192 kHz small enough to not distinguish any smaller difference. But of course it´s easier to make a good filter on a higher sampling frequency, so the DAC in Allo Boss (TI PCM5122) is working internally on 384 kHz. This means the signal is up sampled to 384 kHz. So internally the filter then can be more optimal having 384 kHz than “only” 192 kHz, but taking samples above 192 kHz is probably not going to make things much better.

What does matter is having a very good clock signal, like Allo Kali have. Actually, Allo Boss I didn’t see data on the clock jitter. Maybe you have data on how the Boss’s clock compare to All Kali’s?

The other factor is having a stable and clean voltage feed to the analog circuits and clock generator, as this becomes direct distortion added to the output signal. The Allo Boss is designed, as far as I understand, with this philosophy in mind. Correct me if I got it wrong.

So the gain in audio quality is much bigger handling jitter and a stable voltage feed than 192 to 384 kHz to my reality.

Not much to correct seems that you read some whitepapers :slight_smile:. Good.

Analog design its an art…thats one of the first things I learned . Of course its not true…not entirely . First you need to take care of electrons , clean and plentiful power is the first key. Second even if one door is open , the maze is not solved. With clean power, on the sigma delta , jitter is the most important thing. Kali has about 3ps of jitter and Boss is under the measuring floor of our machine at about 0.63 ps. However you need to understand that at picoseconds level the difference between 3 and 0.6ps is just too small to imagine or for our brain to distinguish (3ps = light travels 1 millimeter) .

So yes analog design is a whole, everything matters in various degrees (like one of my friends from forums says). The power supply , decoupling , PCB routing , resistor (thin film), capacitors (film preferably ) , jitter and of course the DAC IC.

Its an art only in the sense that with hard work you must create something beautiful , bigger than the sum of its parts. And yeah , hope that it becomes commercially a success…

:blush:

Ok, so I’m pretty set up for the Allo Boss DAC, but before choosing I have one more idea to improve my setup. I wonder if the Allo Boss DAC can be used in a multi speaker (not multi room) setup?

Here is my idea:

  1. To put one set of RPi + Allo Boss + Volt + Allo Capacitance Multiplier + Power supply 5V + 24V in each two way speaker, having the RPi via LAN receiving one channel, for example left front channel splitting it up in bass and tweeter signal and sending it through I2S to the Allo Boss using the one channel for bass (20-1500 Hz) and the other for tweeter (1500-20.000 Hz), then powering it via the Allo Volt and output it straight to the speaker (no passive filters in between), mounting all at the back of the speaker. As an additional point I would like to be able to EQ the speaker using that RPi with working software as well.
  2. To put together several speakers with the above configuration in a 5.1 (or 4.1 system as I don’t have a center speaker) that are connected to my network.
  3. Then to have another RPi that has some software that can control the music streams to each speaker, sending it via the network to each speaker, timing it correctly. This would be pretty much like how Sonus is working.

I don´t know if this is possible software and hardware-wise, but I see a future market for your Allo products mentioned in point 1 to be used in such a setup.

What is your take on this?

Any known software which could handle this setup of multi speaker streams (not multi room)?

3 weeks have passed but i don’t see any closed cases on your website suitable for the RPi and Boss.

Hi

we are waiting for the final spacers…on Monday we will post the pics of the casing and hopefully by Friday we will take orders.

Hi,
I am new to the audio DAC thing. After reading this review I ordered Allo Boss DAC and installed on RPi 3 together with DietPi image. I install also Mate desktop and in setup I chose Allo Boss audio card. After reboot I tried to play music video from you tube in Firefox browser. When I started playing video clip I heard high pitched disturbed sound when add in that video was playing. After that add finished the rest of the video played normally.
My question is do I missed something in stetting, some extra codecs needs to be installed or some function in DietPi Config.txt needs to be enabled/disabled.
Thanks in advance for any help.

I think that the adds are not 44/48Khz sample rate. Master dacs will only play files that are 44/48Khz or exact multiple

Thanks.
I was thinking abut the same, that adds must be made with sample rates Boss don’t recognize.
I have another question.: Do Allo Boss driver is incorporated in Max2Play image?

Boss driver is already on RPI mainline (for the past week) but it depends on when the player software updates the kernel.
I will check with Max2play .

Thanks for trying to help.
I installed Max2play today and there is the option to install Allo Boss sound card.
now i understand what this review was about. I compared Allo Boss to regular pc Sound card,
not only I hear the music but also I filed the sound. The Boss is real little gem.
Btw what you mean by “RPi mainline”

Rasbian (RPI OS)

Thanks Johan