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Thread: New toy for all M2/BSS/Crown and others with BLU link input devices

  1. #1
    Member sebackman's Avatar
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    New toy for all M2/BSS/Crown and others with BLU link input devices

    Dear all,

    One of the potential weak links with digital dsp is the ADC in the analog input. I have over the years tried to mitigate this by using BSS digital input cards and fed them digital AES signal.

    Now there is a new kid on the block launched by BSS. It's not out yet but will be in a few weeks. It's an USB to BLU-link device and for those of you using a compter to feed your system music it will avoid any digital-analog-digital conversion. This should have potential to improve sound quality. It also works for all Crown amps with BLU-link.

    http://bssaudio.com/en/products/blu-usb

    Kind regards
    //RoB
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  2. #2
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    Very good ! Thank you.

    Have a nice week end.

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  4. #4
    Senior Member baldrick's Avatar
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    Looks pretty cool, not too expensive either: https://www.bhphotovideo.com/c/produ...sb_audio_.html

  5. #5
    Administrator Mr. Widget's Avatar
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    I'm no expert in all things digital, but this may offer more convenience than ultimate audio upgrade. Apparently the USB audio path tends to be wrought with jitter which may not be dealt with when going this route. The best USB adapters/converters are quite costly and many consider them worth the cost.

    I'm not able to quantify or objectively prove it, but have been told by those I trust that jitter is one of the key components in digital audio reproduction that imparts that hard edged or bright sound many who dislike digital audio complain about.


    Widget

  6. #6
    Senior Member grumpy's Avatar
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    Even at that price, there are options that may be comparable (USB to spdif/aes bridges) and offer similar convenience, e.g., the unit from Halide that's been around for awhile. If one already had a Harman blu-link system, this would add a fun/easy input interface if you can stick to 48/96KHz. Cool that it has an 8x8 mode as well (thinking HTPC connection).

  7. #7
    Member sebackman's Avatar
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    Here is some input from my findings.

    I do apologize for the rather lengthy post.

    I thinkkeeping the signal in the digital domain “all the way” does often help. Howeverthere are many things in the digital chain that also need to be factored in andmy view is that many people are looking in the wrong place to find improvements.If not done right, an analogue input to the DSP may well be a better choise.

    Source material comes with different native sample rate. CD’s and someon line services like Tidal are 44,1kHz, DVD and much other on-line material is48kHz (like YouTube) and there are also some high resolution files that arenative 96kHz. Everything that is between or above is sample rate converted, “SRC”,one way or the other.

    All digitalequipment does run an internal clock for the digital circuits. Anomalies inthis clock or the inconsistent application of the clock pulses lead todisturbances referred to as jitter. Over the last 5 years the clocks haveimproved much and the new “femto clocks” are very precise and stable. Pricesfor good clock implementations have gone down so this is less of a problem todayas far as I can understand.

    In myview the jitter problem has migrated from internal jitter to the connection betweenunits but is still often referred to as jitter in the one or other unit. Eventhe smallest difference in clocking between two units will create audible jitter.

    SPDIFand AES does not contain a clock signal, it is just the pulse train (Blu Linkdoes). Different manufacturers implement standards and interfacesdifferent. Receiving units must be ableto receive all incoming pulse trains regardless of the sample rate and bitdepth.

    They wayto deal with this is to introduce a sample rate converter “SRC” to “re-clock”the incoming pulse train to match the internal clock in the receiving unit.This process is difficult and expensive to get right and I would argue that mostthe jitter people can hear comes from this process in a digital chain.

    I have agood quality asynchronous soundcard with a femto clock and when set to 24/96 outfeeding my BSS BLU160 with SPDIFF signal even that very small clock differencesleads to audible noise when the SRC in the BSS is turned off. I can only hearthe noise when music is off otherwise it is masked by the music. With SRC on itis completely silent. Sound is better with SRC turned off when listening tohigh resolution material.

    In astudio this is mitigated by all equipment running the same sample and bit depthsettings and using a central “word clock”, a physical unit in the studiorunning as master clock for all units. This opens for turning the SRC’s off,which is possible in pro gear but seldom in consumer devices.

    In theHiFi world we can get our digital SPDIF/AES signal from a CD/DVD/Media streameror a computer. I will only focus on computer source here as that is what thislittle device can be handy to improve.

    Thecomputer can output sound to an external sound card over FireWire or USB and weoften set whatever clock/bit we like in the OS. It is often perceived thathigher is better. Reality is not that simple. The best would be to set thecomputer to output whatever native sample rate the source material has andtrust that the sound card does a good job to D/A convert and/or send on to aseparated DAC.

    We couldstop here and all would be just great and peachy. This is not the case.Dependant on the sound card and the SW drivers it is not unlikely that some of theSRC process is run in the computer or in worst case in both places, computerand soundcard.

    Most newsound cards use asynchronous USB and that should not introduce too much jitter.SRC’s does. Please see link.
    http://www.audiophilleo.com/definitions.aspx?Asynchronous%20USB

    AsynchronousUSB can send any native sample rate format to an external sound card with thecorrect SW player. Some USB devices (sound cards or DAC’s) can do all formatsfrom input. Some of them claim to, but in reality the sample rate conversion isdone within the OS in the computer.

    Theproblem appears if the sound card can do only “computer sample rates” beingmultiples of 8, ie 48kHz like I believe is the case for the Sound Blasterfamily. Then I think the computer re-clocks 44,1kHz to 48kHz and send to thecard where it can be kept or up-sampled again as set. I’m not sure about thisbut this seems to be the case.

    Thereshould be very little jitter from a connection between the computer and an asynchronoussound card. There can be jitter introduced by potential up-sampling in thesound card, from the DA conversion and if a separate DAC is used the same isapplicable there. If the connection is SPDIF/AES to and external DAC a newjitter source comes from the SRC in the DAC. -Unless using I2S which is thenative language of DAC chips, or use the same clock in both units.

    TheBlu-USB device offers to avoid the analogue to digital conversion in any Crownor BLU-Link equipped device. That must be a good thing. I assume that thedevice is asynchronous USB (not mentioned in doc’s) so little jitter should beintroduced in the connection between the computer and the device. BSS/Harmanknows the essence of good internal clock so that should be “good enough”, butif not the BLU-Link contains clock so by setting the BSS/Crown receiver (BLUunite or power amplifier) as master clock, jitter should be reduced and SRC’sis not needed. So far this seems to be a great device.

    Thedocumentation says that it can only do computer sample rates 48/96 input whichmeans that for all the 44.1 material the computer must SRC before sending 48 or96kHz to the device. This is a down side, however W10 has a pretty good soundstack and SRC is done pretty good. I will test when I get my hands on one. Ihave a BLU800 so I should be able to switch between BLU-Link in and 24/96 AES frommy sound card.

    Anotherobstacle may be that digital volume controls are sensitive to bit depth at lowlevels. Is the bit rate 24 bits or better the use of a digital volume controlmay be barely audible except at the absolute lowest listening levels. Manyunits use 32 or 41 bits internally and that should be acceptable even at lowlevels.

    If not,an analogue volume control will have to be inserted between the DAC and thepower amplifier. For 2-channel applications there are many alternatives. For 4-channelthere are also many alternatives, active (VCA) and passive (potentiometer). Ifwe go balanced 4-channel (active M2 setup) we need 8-channels which is lesscommon. Here is one alternative.
    https://spl.info/en/products/monitor-controller/volume-8/overview.html

    The factthat this device does 8 channels in and out should open for HT use as mentionedabove. That alone would be a game changer to keep all in the digital domain allthe way to the DAC’s.

    I haveone on order and will revert when I have tested it and compared it to mystandard set up with BSS digital input cards fed with balanced AES and aseparate balanced analogue volume control (Burr Brown PGA2310) after the BSSdsp.

    Mystandard setup uses the SRC in the BSS as my sound card does not have wordclock in or out. However, the German manufacturer Mutec does. Once I persuadedmyself to cough up the dollars I may try their MC-3+ USB that can clock my BSSand remove the need for the SRC. It also has a SPDIF in so I can use the signalfrom my existing CD/DVD player.
    http://www.mutec-net.com/product_mc-3-plus-usb.php



    Kindregards
    //RoB

    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  8. #8
    Member sebackman's Avatar
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    Sorry for the word clutter above. For some reason some words lose the space to the next word when text is cut and paste from MS Word.
    //RoB
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  9. #9
    Member sebackman's Avatar
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    In operation

    Dear all,

    I just wanted to give some feedback here.

    I got my unit a few weeks ago and it is now in operation and I must say that it does sound good compared to my other signal paths. I don't have access to a really esoteric DAC or sound card but pretty descent units. I cannot find that the stand alone unites do sound better.

    I think the fact that the unit is asynchronous and uses the clock in the DSP so there is no SRC involved may be part of it.

    I'm not turning back.

    Nest step is to test the "8 channel out" function and see if can be used to HT sound out direct to a BSS DSP.

    Kind regards
    /Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

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    Hi to all

    This is my first post in forum so hello everybody


    I`m in process of ordering necessary components for diy M2
    I purchased 2216Nd, horn lens, D2430K already arrived

    Can i go this way:
    From my main source PC to Blu-USB to BSS-BLU-50 to Crown amps?
    If I`m correct which Crown model is better for use with M2, CTs, Macro,Xti...
    I probable will by used from ebay.

    Thank`s
    Last edited by agronk; 12-13-2016 at 11:57 AM. Reason: repair

  11. #11
    Member sebackman's Avatar
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    Hi agronk,

    Welcome to the forum.

    You can certainly do that and with excellent results. BLU50 has BLU-LINK in and will act as clock master for the BLU-USB. The BLU-USB can handle 8 channels so for HT use yo may consider a BLU160 or BLU800. If it is just for two channel the BLU50 will be perfect. And it is fan less as far as I know so no extra noise from the unit.

    When it come to amps you can pretty much use whatever you like. Most people seem to like the 2216 with a big amp that can control the cone but I have friends that drive them with 250w with excellent results.

    There are many good amps out there in the form of Crown, Mark Levinson, Bryston and many others. Pic your favourite and you will be happy. The needed level adjustments can be done in the BLU50 so gain is not a problem.

    As you will put in some time and money in this project I would avoid the most basic amps regardless of what brand you go for. You kind of get what you pay for...

    The one thing I would suggest is to use one stereo amp (same model) for each side as different amps may have different character and it can be difficult to bring them together. Plus you can use a slightly smaller amp as you will have more power for the 2216 channel as the other channel driving the driver will use the voltage swing but not really the amperage.

    I personally, after trying many different brands and modells, got stuck on Crown CTS series. They are not the most fancy amps and they do make some fan noise when run hard (that can be cured se other thread here on the forum). However they are constructed by some one with good skills (rumour by someone at ML) and they sound real good both a low volumes and very loud. I only use the class AB amps (600, 1200, 4200 and 8200) but others here are using 2000's and 3000's (class I) and seem very happy with them ( I use British MC2 class AB amps for high power). I first used CTS some years ago and later decided that HiFi amps would probably be better so I bought and sold a large number of "brand" amps but at the end I got back to where I started (less few bucks ...) And I have not looked back since. I think I have 12 of them or so... :-). They drive pretty much all my speakers and they are all fed by BBS units.

    Kind regards
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  12. #12
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    Smile

    Quote Originally Posted by sebackman View Post
    Hi agronk,

    Welcome to the forum.

    You can certainly do that and with excellent results. BLU50 has BLU-LINK in and will act as clock master for the BLU-USB. The BLU-USB can handle 8 channels so for HT use yo may consider a BLU160 or BLU800. If it is just for two channel the BLU50 will be perfect. And it is fan less as far as I know so no extra noise from the unit.

    When it come to amps you can pretty much use whatever you like. Most people seem to like the 2216 with a big amp that can control the cone but I have friends that drive them with 250w with excellent results.

    There are many good amps out there in the form of Crown, Mark Levinson, Bryston and many others. Pic your favourite and you will be happy. The needed level adjustments can be done in the BLU50 so gain is not a problem.

    As you will put in some time and money in this project I would avoid the most basic amps regardless of what brand you go for. You kind of get what you pay for...

    The one thing I would suggest is to use one stereo amp (same model) for each side as different amps may have different character and it can be difficult to bring them together. Plus you can use a slightly smaller amp as you will have more power for the 2216 channel as the other channel driving the driver will use the voltage swing but not really the amperage.

    I personally, after trying many different brands and modells, got stuck on Crown CTS series. They are not the most fancy amps and they do make some fan noise when run hard (that can be cured se other thread here on the forum). However they are constructed by some one with good skills (rumour by someone at ML) and they sound real good both a low volumes and very loud. I only use the class AB amps (600, 1200, 4200 and 8200) but others here are using 2000's and 3000's (class I) and seem very happy with them ( I use British MC2 class AB amps for high power). I first used CTS some years ago and later decided that HiFi amps would probably be better so I bought and sold a large number of "brand" amps but at the end I got back to where I started (less few bucks ...) And I have not looked back since. I think I have 12 of them or so... :-). They drive pretty much all my speakers and they are all fed by BBS units.

    Kind regards
    Thank you, sebackman for your reply

    And clarifying the use of PC as source with BSS/USB and BSS/BLU-50 seems that is all needed as (DSP, crossover,EQ) for JBL M2?

    I will use M2 only for stereo, I mostly listen to music, for HT I have another system
    but i will upgrade if necessary later, it`s all the meter of cash I`m trying to complete M2 with minimal expenses
    i`ts very hard in my pour country to make money!!
    I don`t have any experience with Crown amps except what I`m reading on forums!
    So any recommendation are welcome? is it necessary for power amp to have BLU-LINK too?
    There are a plenty of CTs-3000,also XTI-2000 and Macro tech-2400 with good prices here locally, which series should I chase?
    I have a good chance to by Lab Gruppen FP1000q with reasonable price
    Does anyone tried this amp?

    Thank you
    Agron

  13. #13
    Senior Member srm51555's Avatar
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    I know it's an older thread but does anyone else have any experience with this unit. I'm using the Crown DCi 4300N on my DIY M2's and
    wanted to use the BLU-Link feature mainly because the CD player isn't feeding the amp the 1.4Vrms it wants.

    I'm not 100% sure but I think the DSP in my Crown only processes at 48Khz so that may be another bottleneck I have. For those who have them, the iTech 5000 processes at 96Khz.

    Thanks to member Negseg(Todd) for this networked audio idea



    Thanks,
    Scott

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