Problems with bass in SigmaStudio and ADAU1701

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Hey all!

I am currently working on tuning my DIY speaker, but I have some bass problems.

When I play at 80% volume, the bass plays very well and still is clean, but when I play it at 100% volume, the bass drops so much that it is less bass than what I had at 80% volume. As if I lower the volume for the bass, while in reality I actually increase the volume..

Has anyone experienced this too? Or does anyone know how to solve this?

Im using my fully custom FXtreme DB450 boards for this, which has the following specs:


-CSRA64215 BT

-TPA3116D2 x2 (4 channels, set to 26dB Gain)

-TPA6132A2 opamp (Between BT and DSP, Gain set to 0dB)

-AD8608 Precision opamp (Between DSP and Amp chips)


BTW: The high gain in SigmaStudio is for low-volume Bass Boost, as far as I know that is not the problem.

Note: Got it all fixed, there was a problem in my design..


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Just another Moderator
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I'd guess that the TPA3116D2's thermal protection circuit is probably kicking in. You may not have adequate heatsinking. Alternatively it could be that 100% volume drives the amp into clipping, and once again protection is kicking in.

That's really no problem, the heat sinks on the chips are at least twice as large as TI recommends, and the chips only run at 16v @25W 4R .. I have already checked the output of the amplifiers with an osciliscope, but everything is as clean as it could be. I have a different build with exactly the same amplifier, which runs higher wattages. but that is a 2.1 system, so somehow I have no problems with that ..
Never used those compressors or not sure whats in the compressor setting image, but looks like you've got very long release in that big window, 2 seconds? Ratio seems to be over 7, so loud kick hit comes and then it takes 2 seconds for the compressor to release that reduction. Your threshold is so that at 80% volume there is no compression and after that it is compressing almost all the time because of the long release.

Is there somewhere makeup gain? Normally, a compressor will Reduce volume and it is increased back with "makeup gain". Expander would increase volume.

Like I said, not sure how these compressors you have actually work, but check if your settings are doing what you think they should. A compressor should compress the loud hits (which would overload the amp or the driver) and boost the softer hits (with the makeup gain).

Have fun!:)
I've got ADAU1701 but never used its compressors so cannot recommend one. I think there is some kind of MaxxBass module as well to try out if you wanna boost bass? It will add harmonics and all sorts of magic trickery :) I'm not sure what your goals are since in general compression in playback is not desired and won't protect drivers (except perhaps from over excursion until voice coil is toast). I've only ever used audio compressors during recording and mixing music ;)

If you want especially to use compression you could try more sensible values first like ratio of 2:1, attack 20ms, release 200ms (or automatic setting), threshold to some value you hear the compression at some loud volume (-10db or something). Then add gain block after the compressor to make the reduced gain back up. If kick drum shows for example 2dB reduction on hits, you could make up 2dB. Point is not to make up more than you reduce with the compression (to avoid clipping).

In general, compressors are easier to tune to sound bad than good :D

Have fun!
Got it all fixed! Apparently it was the fault of not having a HighPass in the EQ2 in my design. I still did make a intirely new design which works even better, while still using the same exact Compressors. Quite an easy fix after all, maybe i should have started with something easier haha
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