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:
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:
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:
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:
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:
Some or all of this may be due to ADC noise. Again hard to say.
IMD shows the penalty here:
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:
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:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
This is how the pair look:
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:
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:
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:
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:
Some or all of this may be due to ADC noise. Again hard to say.
IMD shows the penalty here:
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:
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:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).