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Review and Measurements of BSS BLU-BIB & BLU-BOB1 DAC/ADC

amirm

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#1
This is a review and detailed measurements of Harman/BSS BLU-BIB 8 channel analog to digital converter (ADC) and BLU-BOB1 8 channel digital to analog converter (DAC). They are on kind loan from a member. The BLU-BIB retails for I think US $930 and so does the BLU-BOB1 but I see the latter on Amazon for US $790 and free shipping.

This is how the pair look:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 Audio Review.jpg

I suspect most of you are not familiar with these two products. BSS is a company that Harman acquired a few years back. Their speciality is audio signal processing/DSPs that are easily programmed using their interactive software. The BOB1 and BIB are expansion output/input modules should you run out of ports on their DSB units. All products communicate using physical Ethernet link but not logical. That is, you can't talk to them from a computer but they communicate with each other over this link and can handle up to 255 channels of digital audio with sample rate up to 96 kHz. FYI, JBL Synthesis products use the same subsystems for room eq/crossover and digital link.

While you can normally configure BSS products using the PC software, the BiB and BOB are "dumb" devices in that you set their channel assignment using DIP switches and rudimentary front panel. It does work very reliably though as there is nothing to configure to have networked, digital audio with low latency and redundancy. After setting the switches the two immediately started to talk to each other.

This is the back panel:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 Back Panel Audio Review.jpg

Input and output on all BSS products use phoenix type connectors. For testing then I had to wire up an XLR cable using the male screw terminal. The use of these connectors allows much higher density of inputs and outputs than XLRs. They are not locking though as XLRs are.

Both units run quite warm.

Note: may company, madrona digital, is a dealer and has close relationship with Harman. We install a ton of BSS gear, usually for whole house audio distribution and such (we use the DSP to tailor the sound to in-wall/in-ceiling speakers). I also personally have the JBL Synthesis Room EQ/Processor in my theater which likewise uses BSS processor. So feel free to read as much bias as you like into my review.

Audio Measurements
The BIB and BOB can be wired to create an analog in/analog out chain with ADC and DAC conversion in between. As is, there is no way to feed either a digital stream without a Blu DSP controller. I have one but it is wired up good in my theater audio system and I am in no mood to rip it out for this or any other testing. :) So this testing by definition tests the combination of both the ADC in BIB and DAC in BOB1.

I only wired up one channel and so this is our dashboard view:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 Audio Measurements.png


Our SINAD is just 83 dB. The Audio Precision analyzer in similar loopback garners over 120 dB so we have degraded things quite a bit here. Whether it is the ADC or DAC that is the weak link is hard to say. We are beating the spec of 0.01% distortion for BOB1. I am not going to put this in our SINAD chart since it is not just a DAC score but if I were to to do that, it would fall in the fourth quadrant of all DACs tested.

SINAD is limited by the second harmonic at around 82 dB. Were it not, the noise around 200 Hz would have done the trick just as well. We have a lot of noise components which also show up in jitter test:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 Jitter Audio Measurements.png


Left side is pretty ugly. I suspect the digital side of either device or both is bleeding badly into the analog portion/DAC/ADC.

Signal to noise ratio falls short of specifications:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 Dynamic Range Audio Measurements.png


Some or all of this may be due to ADC noise. Again hard to say.

IMD shows the penalty here:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 IMD Audio Measurements.png


At low levels of input (left of the chart), noise dominates to a very high degree. We have some saturation above voltage levels of 1.2 but fortunately, it stays mangeable and there is no sharp peaking. BTW, I increased the gain one notch to get unity gain out of the full chain (lowest gain produced have as much voltage).

Frequency response was a surprise:
Harman BSS Soundweb BLU-BIB and BLU-BOB1 Frequency Response Audio Measurements.png


The digital link operates at either 48 kHz or 96 kHz. So worst case situation should have been 24 kHz of bandwidth for 48 kHz sampling. But we stop at just 22 kHz. Something is limiting the bandwidth more than it should.

Because of this limited bandwidth I could not run my multitone test.

Conclusions
The BSS BLU-BIB and BLU-BOB are specialized ADC/DACs used very frequently in wide range of audio/system integration. They are not exactly consumer, or hi-fi gear. They are designed to do a job and that is that. Before going into this test, I feared that the performance would not be good and that is what we got. What is there is fine for movies as I use it or general audio distribution. But not a good choice for high-fidelity experience.

-----
The weather is getting warmer so I am having craving for some nice ice cream. You know, the kind that is made with real cream as opposed to a bunch to chemicals. Please donate some funds so that I don't feel guilty using my own money for it using:

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restorer-john

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#2
Have you done an A/D- D/A test on any other standalone devices other than the AP loopback?

Those figures above for the Soundweb are bettered by many old DAT recorders in A/D -D/A in 1991.

Interesting nonetheless. :)
 

rajapruk

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#4
Thank you very much for this test.
Greg Timbers (iconic JBL speaker designer) once hinted that BSS is no good (analog performance).
I think I will use my BSS BOB2 for rear channels down the road, in my combined music/cinema setup. And get a Okto Dac8 Pro for the front.
 

Blumlein 88

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#5
Oh another clear case of Amir's incredible bias. He uses this company's products so it gets a really good review. Oh wait...........................................

Okay, okay, I can still find bias. He uses the product and it gets a poor SINAD and he arbitrarily decides not to put it in the SINAD chart. Okay, best I can come up with. Oh and you use the excuse of looping to give an out.............well, except you said pro devices would loop much better. Dang!

Once again, thank you for illuminating another piece of gear and its real performance. And a big thank you to owners loaning you the gear. Thanks rajapruk.
 

rajapruk

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#7
I wonder how much the ADC is the problem here. Is ADC process usually adding distortion, and to what extent? Is ADC usually more degrading than DAC, or the other way around?
 
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#8
But not a good choice for high-fidelity experience.
What does this mean? The experiences of people detecting sub -80db harmonics/noise are pretty much non existent in reality. So it's extremely unlikely that this device would affect someone's music listening experience in some detrimental way.
It would be nice if What-hi-fi-isms/Steve Guttenbergisms were avoided in your conclusions...
 

anmpr1

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#9
What does this mean? The experiences of people detecting sub -80db harmonics/noise are pretty much non existent in reality. So it's extremely unlikely that this device would affect someone's music listening experience in some detrimental way.
It would be nice if What-hi-fi-isms/Steve Guttenbergisms were avoided in your conclusions...
When there is a product that is objectively better, for similar or less dollars, then there is really no compelling reason to select gear that measures worse, even if you can't hear any difference. Unless there are special circumstances (installation requirements, dealer support, etc) that would dictate otherwise. And, by the way, even Steve Guttenberg will tell you that if you want SOA engineering you should get the Benchmark.
 

amirm

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#10
I wonder how much the ADC is the problem here. Is ADC process usually adding distortion, and to what extent? Is ADC usually more degrading than DAC, or the other way around?
Hard to predict. If I were to guess I would say that they are both equal in performance in which case a single one would be 3 dB better in SINAD.
 

amirm

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#11
What does this mean?
It means that I won't give a free to pass to equipment that can't even do justice to CD's 16 bit format, nearly 40 years after its invention. I want transparency for such content and I am not going to get it with a distortion product at -80 dB.

The experiences of people detecting sub -80db harmonics/noise are pretty much non existent in reality.
I can't go by anecdotal assertions like this. It is not like such a test has been run in controlled manner and showed no outcome. You are relying on negative logic. From psychoacoustics point of view, we can show that even CD's full dynamic range is not quite adequate for transparency let alone something that is much worse.

The spectrum of THD+N is the governing point here by the way, not the single number you are using. So for a test to be broadly applicable, it would need to cover many combination of noise+distortion profiles -- something that is impossible to do in practice.

So it's extremely unlikely that this device would affect someone's music listening experience in some detrimental way.
It would be nice if What-hi-fi-isms/Steve Guttenbergisms were avoided in your conclusions...
Please don't give me advice like this. This is not my first rodeo. I have high standards for engineering and strive for transparency. If I said something is so, I need to be able to prove it for all people, all content and all situations including sensitive headphone listening. I can't wave my hand in the air as you are doing and declare systems that are 30 dB worse than the best as being transparent.

Yes, it is very likely that most audiophiles will flunk such a transparency test. If that is what you want to say, fine. But please don't couch it as me having to lower my standard to that of theirs. I can pass many double blind tests they cannot. And there are people with far fresher ears than I have.
 

amirm

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#12
It was not my unit that got tested, just to be clear.
Correct. The owner is offline so hopefully he will come back soon to see the results! Poor guy sent me all this gear back in January and just now I am getting to reviewing them. So he may have given up on me. :)
 
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#13
Yes, it is very likely that most audiophiles will flunk such a transparency test.
Well, then this directly contradicts your closing statement because most (and it's a hell of an understatement really) audiphiles's high-fidelity experience won't be affected at all using such equipment.
The issue is only wording really, I've no problem with you claiming that this equipment won't be enough under ideal conditions, with ideal recordings and using diamond, virgin ears, but claiming that in general high-fidelity experience won't be achieved with such product makes makes me wanna slap you with TOS #8 ;)
 

amirm

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#14
The issue is only wording really, I've no problem with you claiming that this equipment won't be enough under ideal conditions, with ideal recordings and using diamond, virgin ears, but claiming that in general high-fidelity experience won't be achieved with such product makes makes me wanna slap you with TOS #8 ;)
As much as I dislike subjectivist forums, I am just as much against extremist objectivist forum where you got that TOS from. :(

So, no, your argument does not stand. I am here to recommend gear that passes for transparency. That is, it has no chance of embarrassing you one day because someone can tell one from another. Such has been the case about these extremists challenging me on double blind tests, only to see me pass them.

People come here to learn about excellence in audio. They want to know that what equipment will completely get out of the music recording. The forum you took that TOS is focused on far lower quality standard. That is not my mission, or that forum.

Read this article before hitting post again: https://www.audiosciencereview.com/...ts-did-show-amplifiers-to-sound-different.23/

I don't want that to happen to anything people buy based on my recommendations.
 
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#15
Well, then this directly contradicts your closing statement because most (and it's a hell of an understatement really) audiphiles's high-fidelity experience won't be affected at all using such equipment.
The issue is only wording really, I've no problem with you claiming that this equipment won't be enough under ideal conditions, with ideal recordings and using diamond, virgin ears, but claiming that in general high-fidelity experience won't be achieved with such product makes makes me wanna slap you with TOS #8 ;)
Then what are you doing posting / browsing here if you don't care about distortion -80db down? There are plenty of subjectivist audiophile forums that cater to this mentality. This happens to not be one of them. So yes, most of us here care about things like a $900 product being outperformed by a $99 one.
 
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#16
So, no, your argument does not stand.
My argument is only about your choice of words, not about the strife for total transparency, which is a good ideal. The quote "[this device is] not a good choice for high-fidelity experience." is simply a lie, and lying is not nice, I hope we agree. The review would be complete without that bit, the numbers alone tell that this device doesn't achieve ideal transparency, but without an appropriate sample of blind tests comparing this DAC with some kind of ideal DAC, no one can seriously make claims about actual audibility of its issues or personal hi-fi experiences, especially given the numbers your measurements show.
 
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bravomail

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#17
Thx for review, Amir! I'm trying to understand the use case for such devices. Is it to pass audio on longer distances within a house - ADC-Ethernet-DAC ?
 

amirm

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#18
Thx for review, Amir! I'm trying to understand the use case for such devices. Is it to pass audio on longer distances within a house - ADC-Ethernet-DAC ?
They are peripherals to an audio DSP which you program to do whatever you want. The software (London Architect) is what makes it powerful and useful. They can be used in everything from live sound, to audio distribution in a home and room EQ. You can route many channels of audio in/out and process them at will. And yes, due to use of simple cat-5 wiring, extensibility is exceptionally easy.

They are not used stand-alone as I am testing.
 
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#19
Thank you Amir for the review!

I just performed some measurements with my poor M-audio card, and the measured noise is really lower than what you obtained here. Equipment under test is BSS BLU-160 with analog input and output cards.

Having a look at the spec sheets of BIB, BOB and analog cards led me to the hypothesis that the BLU-BIB is the weaker link here, at least in terms of noise. EIN and CMRR are quite worst than those of the analog input card. Unfortunately, measured THD is as bad as what you obtained...
 
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#20
I just received my brand new MOTU 828es! Obviously I performed some measurements on my BSS BLU-160, and the results are a lot better than what I obtained with my poor M-Audio...

Test set up is MOTU 828es Analog Out -> BSS BLU-160 analog In -> BSS BLU-160 analog Out -> MOTU 828es Analog In

THD+N at 4Vrms @1kHz:
Capture d’écran 2019-06-14 à 18.10.36.png


Then, THD+N at 2.83Vrms @1kHz:
Capture d’écran 2019-06-14 à 18.11.10.png


And finally, THD+N at 1Vrms @1kHz:
Capture d’écran 2019-06-14 à 18.11.46.png


So it's not wonderful, but it's quite better than what has been obtained using the BOB & BIB. It would take place between the 2nd and the 3rd quadrant in the SINAD comparison graph.

Then I modified some components on channel one of the analog input card, and I obtained these results:

THD+N at 4Vrms @1kHz:
Capture d’écran 2019-06-14 à 15.09.47.png


Then, THD+N at 2.83Vrms @1kHz:
Capture d’écran 2019-06-14 à 15.09.34.png


And finally, THD+N at 1Vrms @1kHz:
Capture d’écran 2019-06-14 à 15.10.39.png


D2 has been largely reduced, D4, D5 and D7 also and total THD is improved by 2 to 5 dB. THD+N is not impacted due to the fact that limiting factor is noise, and the modifications didn't have any effect on noise.
 
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