Subwoofer level from Bluos app (NAD C658)

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46 comments

  • Eli Barbie

    I have the C658 and dual SB2000 pro. The sub output is very low. The only solution is to connect a device like the MiniDSP 2X4 HD between the C658 and the subs. The low sub volume problem seems to be limited to SVS subs only, because I've tried a different subwoofer (some crappy Jamo) and levels were about 10db higher at the default 12occlock position. 

    It seems that the output impedance on the C658 sub pre out is very high, and the input imp on the SVS is very low. Once you connect a device in between, the levels are increased by +6dB even when before applying any boost. With the Minidsp connected in between, subwoofer levels are fine. I set the C658 to a single sub only, connected one sub out to the 2X4HD, connected my two subs to the 2X4HD outputs, ran a REW based calibration until I got a flat response between 20Hz and 150Hz. And only then I ran Dirac Live tricking Dirac into assuming I have a single sub. 

    I'm very pleased with the results! This is just like having Dirac Bass Control. 

    I also have a Yamaha RX-A2080 AVR. Its main front pre outs are connected to the C658 line 1 at fixed vol. The Yanaha YPAO is set to YPAO:Front, so all other speakers are aligned to have similar EQ as the front, which are calibrated by Dirac Live. I have two NC400 power amps for the front channels. 

    In the manual speaker config of the A2080, I've disabled the subwoofers. This why, the AVR thinks that my front speakers are full range, directing the LFE effect to the main fronts.

    Such config allows me to get subwoofers working even in Pure Direct mode, otherwise not possible with the Yamaha. 

    Yes, there is a subwoofer bug in the C658 when combined with an SVS sub, but it can be easily fixed if you invest in the MiniDSP 2X4HD. 

    BTW, this is my second C658 unit. None were actually defective! The low sub is a hardware design flaw. 

     

     

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  • Josh Bauch

    The brand of sub doesn't matter since the issue is with the sub output level from the C658.  Both a Golden Ear SuberSub-X and JBL E112 failed to produce viable bass when hooked up to the sub out, only when hooked up to the RCA line out did they get adequate signal to properly function.

    Also the issue has been acknowledged, just probably won't ever be fixed, so don't buy a C658 if you plan on using the sub out.  Also note hooking up the sub via RCA rather than the sub outs means you can't segregate the sub from the mains for DIRAC calibration or curve setting.

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  • Eli Barbie

    Once again, using a MiniDSP 2X4 HD (100$) solves the low output level (it can add up to 24dB boost). it also can drastically improve bass response if you use dual subs and know how to use REW.

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  • Matt G

    Again, "just buy a signal processor " isn't an acceptable answer to me. I realize that's a workaround and I'm not doubting its effectiveness, but this isn't a $299 Sony I picked up at Best Buy. It'd be like buying a brand new BMW with no driver's seat in it and then settling on "well I just put a bucket on the floor and sat on that instead." It's absurd that after selling this product for like two years now that they won't acknowledge it and still haven't done something to remedy it, even in new units being sold. I suppose if you've had one for a while and you're outside of your return period the signal processor is a good way to go, but for anyone buying new or still within your return period, I'd say "run away." This was my first NAD purchase and for them to miss something so basic and critical in the production of a piece of equipment, to me it doesn't speak very highly of their quality control.

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  • Gianfranco Pezzino

    Matt G I agree that this is an unfortunate situation. I called Crutchfield (the US dealer where I bought the unit), they said that NAD acknowledged the issue, could replicate it and sent the information  to their developers. So perhaps there is hope for a fix.

    For me it is difficult to find an alternative that would fit all my requirements: Streamer, preamp, Roon ready, phono input (MM), sub out, room correction (DIRAC or other). Do you have any suggestions?

    Eli Barbie I purchased the mini DSP 2x4 HD (which incidentally is $200, not $100). I just tried really quick to hook it up last night but I could not detect any improvement, I will try again. What gain do you increase? Input or output?

     

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  • Gianfranco Pezzino

    So it looks like even with the Mini DSP 2x4 HD the sub out port does not work for me. I get a very faint gain increase but nothing that would make the sub usable. My only option is using the preamp out port on the C 654, which honestly works fine but does not allow to integrate the sub into the DIRAC room correction.

    Attaching screenshots from the Mini DSP with and without gain correction in case anyone has ideas why the gain is so small.

     

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  • Eli Barbie

    I've increased both input and output by +6dB and also applied PEQ. I have two subwoofers, both set to -10dB gain using the app. 

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  • Gianfranco Pezzino

    I am totally puzzled. As you can see from the top two photos, I increased input and output gain by +12, but the change in volume is barely detectable with the app (output stops at -73), and not at all by the ear. PEQ should not affect my volume, I suppose. Master volume is on zero. What else may I be missing?

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  • Eli Barbie

    You must update the DSP program after making changes.

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  • Gianfranco Pezzino

    I turned the DIRAC (DSP) off, that should give me full signal through the sub out, but no joy - still too weak...

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  • RickW

    Ok, after wading through all these posts I can't believe that Bluesound/NAD haven't posted a solution or stated when one will be forthcoming. Unless a solution was released elsewhere but not followed up with a post here? The product mgr Tony Williamson's last unhelpful comment was a year ago?! That's completely unacceptable especially for a high-end audio maker. I was ready to go visit my local NAD dealer to  purchase a C658--but there is NO WAY that's going to happen now! Does anyone at Bluesound or NAD care, Tony??

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  • Gordon Delgado

    In a word: No.

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  • Eli Barbie

    The subwoofer output level is the least of the problem. When a subwoofer is enabled, you'll get the clipping distortion on some hot tracks (the Rhye distortion bug). These problems are not limited to the C658, but also affects the M33 and the T778. It seems that NAD are unable to fix these bass management-related issues due to hardware limitationions. 

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  • RickW

    Thx Eli. Wow, unbelievable! How helpful was NAD support in coming to your conclusion? Based on this thread discussion, I can only assume it was mostly due to your diligence and help from other users/enthusiasts. Incredible. NAD/Bluesound should learn from their fellow Canadian hi-end audio equipment makers Bryston.com. The latter is well known for high quality products that are individually and extensively tested before shipping—and their customer support is superior and top-notch. Admittedly Bryston amps are more expensive than NAD’s, but the NAD C658 is not cheap by any stretch at $2000 CAD retail. Very disappointing. I’m going to get my local NAD dealer to comment on all this good stuff! Let ya know if you like. 

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  • andomar

    I bought a subwoofer (B+W DB4S) for my system last week and now I'm running into this problem too (the subwoofer is connected to the C658 via SUBW1).

    After many wrong attempts with cables etc. I now got it working with Dirac: In the app's volume calibration I had to lower the left and right speakers by about 6 dB to adjust the volume to the sub (0 dB). The Dirac measurement gave a good-sounding result!
    BUT: I now have to set the volume very high (C658 indicates -30 dB) to achieve room volume...
    I don't know if this is a good practice...

    In addition, I have an additional problem with the DB4S, which has an audible noise (when you put your ear to the speaker) that gets louder the higher you set the input level! So it would be good for it to be used with a reduced level, which is exactly counterproductive to the C658 problem...
    This noise problem is also well known to B+W, as I could see from some forums.

    As an end user you are once again the stupid one. Eat or die.
    Unfortunately, you experience this again and again: HiFi, cars... etc. :-(

     

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  • Tony W.
    Product Support Manager

    Hi Andomar

    Please contact support@nadelectronics.com - they will be happy to provide some hints.

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